Knee Pain Approach: Diagnosis & Evaluation in Adults

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Approach to the adult with unspecified knee pain
Authors: Carlton J Covey, MD, Robert H Shmerling, MD
Section Editor: Karl B Fields, MD
Deputy Editor: Jonathan Grayzel, MD, FAAEM
All topics are updated as new evidence becomes available and our peer review process is complete.
Literature review current through: Nov 2021. | This topic last updated: Oct 27, 2020.
INTRODUCTION
The knee has the largest articulating surface of any joint. Depending on the activity, this weightbearing joint can support two to five times a person's body weight. Chronic knee pain affects 25
percent of adults and has a deleterious effect on daily function and quality of life [1,2].
The general evaluation of the adult presenting with undifferentiated knee pain is discussed
here, including details about differentiating among the causes of knee pain based upon the
history and examination findings. For cases where knee pain develops following acute, lowenergy trauma or chronic overuse, often in athletes or active adults, and is most likely
musculoskeletal in origin, a separate in-depth discussion of how to approach such patients is
provided. (See "Approach to the adult with knee pain likely of musculoskeletal origin".)
BASIC KNEE ANATOMY AND BIOMECHANICS
The anatomy and basic biomechanics of the knee are reviewed separately. (See "Physical
examination of the knee", section on 'Anatomy'.)
HISTORY OVERVIEW AND DIAGNOSTIC CATEGORIES
History-taking for the active adult presenting with knee pain is discussed in detail separately,
but several aspects of the history warrant emphasis. (See "Approach to the adult with knee pain
likely of musculoskeletal origin", section on 'History'.)
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First, the differential diagnosis for knee pain is complex and obtaining a clear history remains
essential for diagnosis. The following flow chart provides an overview of how to approach the
diagnosis of knee pain in the adult (
algorithm 1). Information from the history helps the
clinician to distinguish among five diagnostic categories:
●
Acute knee pain following recent trauma or overuse
●
Atraumatic knee pain associated with joint effusion
●
Atraumatic knee pain NOT associated with joint effusion
●
Referred knee pain
●
Uncommon causes of knee pain
Several questions in particular are important for narrowing the differential diagnosis and
should be asked of every adult patient presenting with knee pain:
●
Did pain begin following an acute traumatic event? Pain immediately following an injury is
concerning for possible structural damage to the knee. Delayed pain suggests tendon
strains, cartilage contusions, or minor soft tissue tears. The closer the pain onset is to the
specific event, the higher the likelihood of significant structural damage.
●
Is the pain associated with activity (eg, new exercise regimen, change in previous training
habits, day-to-day activity over the preceding few months)? Pain associated with activity
should lead to further inquiry about training equipment (eg, shoes, braces), training
volume (eg, training days per week, duration of training sessions), intensity, and any
recent changes in such parameters. Information about specific activities that trigger pain
can be helpful. As an example, anterior knee pain associated with sprinting or jumping is a
classic part of the history of patellar tendinopathy.
●
In which anatomic quadrant is the pain located (anterior, posterior, lateral, or medial), or is
the pain diffuse or vague? Localizing knee pain to an anatomic quadrant or more specific
location helps circumscribe the differential diagnosis. Pinpoint localization is generally
possible following trauma to a specific ligament, tendon, or other palpable anatomic
structure. Pain described as diffuse or vague may be secondary to injury of an intraarticular structure, a rheumatologic or infectious process, or from referred pain.
●
Has the painful knee been swollen (ie, joint effusion) or erythematous? Rapid swelling
after trauma occurs with bleeding into the knee joint and suggests a significant injury (eg,
anterior cruciate ligament tear). Swelling or erythema occurring without trauma may
indicate an infectious, rheumatologic, or crystal-induced condition and diagnostic
arthrocentesis is often indicated.
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●
Approach to the adult with unspecified knee pain - UpToDate
Are constitutional symptoms, such as fevers, chills, night sweats, fatigue, or rash, present?
The presence of such symptoms and signs suggests a systemic illness and further
investigation of infectious, autoimmune, or neoplastic causes is necessary.
●
Is there a history of prior knee injury or surgery? A past history of knee injury is the most
accurate predictive risk factor for future knee injury. The clinician should inquire about the
type of injury, duration of disability, and the rehabilitation program. Often, a new knee
injury is a complication of an old or concurrent injury. As an example, patellofemoral pain
can develop in patients who alter their running gait due to discomfort from chronic
Achilles tendinopathy. Likewise, prior surgical repairs can "wear out" or fail, leading to
recurrence of the initial condition. All patients with prior injury or surgery experience
some degree of deconditioning while injured and recovering. This deconditioning,
combined with poor or incomplete rehabilitation, predisposes to new injuries.
●
Are there symptoms affecting any other joints? Subjective symptoms and/or examination
findings that reveal multiple affected joints raise suspicion for a systemic or rheumatologic
process.
●
Is there a history of systemic or rheumatologic disease? A known history of a systemic or
rheumatologic disease can help to guide clinical inquiry, physical examination, and
possible laboratory testing.
PHYSICAL EXAMINATION OF THE KNEE
An in-depth discussion of the physical examination of the knee is provided separately (see
"Physical examination of the knee"). A few points about the knee examination are worth
highlighting:
●
When examining the knee, look closely for discrepancies in strength and range of motion
between the painful and asymptomatic joints.
●
Try to reproduce the patient's presenting pain complaint. Many examination maneuvers
cause some discomfort, even when performed on asymptomatic limbs. Therefore, it is
important to use only the most appropriate maneuvers (based on the most likely potential
diagnoses as determined by the history) to reproduce the patient’s symptoms as precisely
as possible. This approach is most likely to pinpoint the cause of the discomfort. Pain
elicited by the examination that is different than the presenting complaint may be worth
noting, but it is often unrelated to the diagnosis.
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●
Approach to the adult with unspecified knee pain - UpToDate
Perform the knee examination systematically. By performing the examination in the same
manner every time, the risk of overlooking an important finding is reduced. Traditionally
the musculoskeletal examination is performed in the following order: inspection,
palpation, range of motion, strength, neurovascular, and "special tests" (maneuvers to
assess a specific diagnosis).
INITIAL STEPS TO CATEGORIZING KNEE PAIN
Step one: Distinguish acute versus chronic pain — For most musculoskeletal conditions, pain
of less than six weeks duration is classified as acute or subacute, while pain lasting longer than
six weeks is classified as chronic. This is by convention, as there is no high-quality evidence
supporting this threshold. However, most minor musculoskeletal ailments resolve within six
weeks of onset with appropriate activity modification. The following flow chart provides an
overview of how to approach the diagnosis of knee pain in the adult (
algorithm 1).
Acute knee pain may stem directly from trauma (easily identified by the history in most cases)
or from regular activity (eg, overuse injury), or it may be unrelated to trauma or activity. It is
important to determine whether the onset of pain was abrupt or insidious. As an example, it is
helpful to know that a patient's pain started abruptly eight weeks ago while running and has
not fully abated. While technically a chronic pain presentation (greater than six weeks duration),
this presentation is consistent with a specific event that caused the acute onset of pain. In cases
involving an abrupt onset or sudden change in knee pain, the clinician should focus on
clarifying the events leading up to the onset.
Some patients complain of a sudden worsening or change in a long-standing pain (ie, acute on
chronic pain pattern). This suggests an overuse injury that has been exacerbated by activity.
Step two: Distinguish traumatic versus non-traumatic pain — The next step is to determine
whether an acute injury has occurred. Generally, this is obvious from the history. Common
examples include a fall, a direct blow to the knee, or a motor vehicle crash. However, direct
contact is not necessary for a person to sustain an acute traumatic knee injury. Adults may
experience acute pain after non-contact trauma, such as running, jumping, squatting, slipping
on ice without falling, or abruptly twisting their knee. Thus, clinicians should inquire about both
contact and non-contact trauma.
Step three: Determine whether an effusion is present — Determining the presence or
absence of a joint effusion is an important part of assessing the patient with knee pain. The
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method for detecting an effusion is described separately. (See "Physical examination of the
knee", section on 'Detection of an effusion'.)
An important adjunct to the physical examination for detecting an effusion is the use of
musculoskeletal ultrasound (MSK US). Moderate to large volume effusions (20 mL or more) are
readily detected by manual examination; however, small effusions can be missed. MSK US is
nearly 100 percent sensitive and specific for detecting knee effusions. This becomes important
with small effusions (5 to 10 mL), which are clinically significant but can be difficult to detect by
physical examination alone (especially in obese or muscular patients) [3]. (See "Musculoskeletal
ultrasound of the knee".)
The presence of a knee joint effusion following acute trauma suggests the presence of
structural damage to bone, cartilage, or a ligament. Non-traumatic knee effusions unrelated to
activity, warrant a more thorough workup, as the differential diagnosis includes an infected (ie,
septic) joint. (See 'Conditions NOT related to activity' below.)
Step four: Determine pain location — Determining the primary location of knee pain is useful
in all cases, but it is particularly important when evaluating patients with non-traumatic knee
pain and no joint effusion. The location of the knee pain (anterior, medial, lateral, or posterior)
helps to inform the differential diagnosis. Ask the patient to point with one finger to the precise
location of the pain.
ACUTE KNEE PAIN ASSOCIATED WITH TRAUMA
The diagnostic approach to the patient with knee pain following acute trauma is reviewed in
detail separately. Clinicians evaluating patients with such a presentation, regardless of the
patient’s baseline activities or whether the trauma involved physical exertion, are referred to
that discussion. (See "Approach to the adult with knee pain likely of musculoskeletal origin",
section on 'Acute knee pain associated with trauma'.)
The differential diagnosis for acute knee pain following trauma associated with an effusion
includes the injuries listed below (
table 1). Note that trauma for the purposes of this
discussion refers primarily to low-energy trauma (as opposed to high-energy trauma, such as a
motor vehicle crash). Patients with knee pain following high-energy trauma may have
significant internal injuries and should be evaluated in the emergency department. (See "Initial
management of trauma in adults".)
Common causes of knee pain following acute, low-energy trauma:
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●
Medial or lateral collateral ligament tear
●
Anterior cruciate ligament tear
●
Meniscus tear
●
Patella dislocation or significant subluxation
●
Patella tendon tear
●
Intra-articular fracture
●
Osteochondral defect
Less common causes of knee pain following acute, low-energy trauma:
●
Bone contusion
●
Posterolateral corner injury
●
Posterior cruciate ligament tear
●
Quadriceps tendon tear
●
Fibular head or neck fracture
●
Patella fracture
●
Knee (tibiofemoral) dislocation
CONDITIONS NOT INVOLVING ACUTE TRAUMA
Identifying the cause of non-traumatic knee pain can be challenging. Determining whether the
knee pain is associated with activity, and whether an effusion is present, are important early
steps in narrowing the differential diagnosis. A table summarizing the major diagnoses to
consider and their distinguishing features is provided (
table 2). The following flow chart
provides an overview of how to approach the diagnosis of knee pain in the adult (
algorithm 1
).
Non-traumatic conditions associated WITH a joint effusion
Conditions made worse by activity — The differential diagnosis of non-traumatic knee pain
associated with an effusion can be narrowed based on the association with activity. Important,
common causes of non-traumatic knee pain that increase acutely with activity include
osteochondral defects and osteoarthritis.
●
Articular cartilage (osteochondral) injury or defect – Osteochondral defects are usually
caused by significant knee trauma but may be secondary to milder trauma or chronic
overuse (eg, osteochondritis dissecans). Patients with such defects often describe diffuse
knee pain that is worse during and after activity. A knee effusion brought on by activity is
an important historical clue, as spontaneous effusions unrelated to activity generally do
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not occur with osteochondral defects. Imaging studies (often magnetic resonance
imaging [MRI]) or arthroscopy are required to diagnose osteochondritis dissecans and
other osteochondral defects.
●
Osteoarthritis – Osteoarthritis (OA) involves degradation and thinning of the articular
cartilage, and OA of the knee is a leading cause of pain and disability worldwide [4]. OA
can present as diffuse or localized knee pain, with or without an effusion. Intermittent
effusions occur in persons with OA when they increase their activity. Patients with an OA
flare often describe a delayed onset to their effusion, which develops 12 to 24 hours
following the acute event. Vague or diffuse joint line tenderness, intact ligaments, and
non-focal meniscus tests comprise the typical constellation of examination findings
associated with OA flares. In addition, many patients are unable to fully flex or extend the
affected knee.
Strongly associated risk factors can help to identify patients in whom knee OA is the most
likely diagnosis, these include: age over 50 years, female gender, higher body mass index,
previous knee injury or knee surgery, malalignment, joint laxity, occupational or
recreational activities that place stress on the knee, family history, and the presence of
Heberden's nodes (
picture 1) [5]. (See "Clinical manifestations and diagnosis of
osteoarthritis".)
There is often poor correlation between radiographic changes and a person's symptoms
[4]. Therefore, the diagnosis of knee OA remains a clinical one and radiographs should not
be used as the sole basis for diagnosing OA. The diagnosis of knee OA can be made
without the use of radiographs or in patients with normal radiographic findings, if each
the following are present [5]:
• Age at least 40 years old
• Activity-related joint pain
• Minimal or no morning stiffness
• Functional limitations, such a declining ability to walk distances or to climb stairs
• One or more typical examination findings (eg, crepitus, restricted joint movement,
bony enlargement)
If a palpable effusion is present, joint aspiration and synovial fluid testing may be needed
to exclude inflammatory disease. The indications for synovial fluid testing are discussed in
greater detail separately. (See "Synovial fluid analysis".)
Conditions NOT related to activity — Knee pain associated with a joint effusion, despite the
absence of any trauma or activity that exacerbates symptoms, is a concerning finding, and
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indicates the need for a more extensive workup. In addition to a careful history and
examination, plain radiographs and knee joint aspiration are often necessary. Important causes
of non-traumatic knee pain that is not associated with activity include:
●
Crystal arthropathy
●
Infectious (septic) arthritis (medical emergency)
●
Disseminated gonococcal infection
●
Systemic rheumatic disease
●
Crystal arthropathy – Crystal arthropathy can present as unilateral arthritis, which may
include acute knee pain and effusion not related to trauma or activity. Local erythema,
warmth, joint pain, and an effusion are common examination findings. Calcium
pyrophosphate crystal deposition (CPPD) disease (ie, pseudogout) most often affects the
knee, while gouty arthritis most often involves in the first metatarsophalangeal joint or
midfoot, although knee involvement is common. A serum uric acid level should not be
used to diagnose an acute gouty flare, as up to a third of such patients have a normal
serum uric acid concentration. While a serum white blood cell (WBC), erythrocyte
sedimentation rate (ESR), and C-reactive protein may be useful for the management of
these patients, they should never substitute for joint aspiration and synovial fluid analysis.
Increasingly, imaging techniques including ultrasound and dual-energy CT scanning are
proving useful in the diagnosis of crystal arthropathy. (See "Clinical manifestations and
diagnosis of gout" and "Clinical manifestations and diagnosis of calcium pyrophosphate
crystal deposition (CPPD) disease".)
●
Infectious (septic) arthritis – Similar to crystal arthropathy, infectious arthritis of the
knee typically presents with local erythema, warmth, joint pain, and an effusion. However,
distinguishing between the two is crucial. Even among patients with risk factors and
clinical findings consistent with crystal arthropathy or other non-infectious causes of knee
pain, infectious arthritis must be ruled out if it is among the diagnoses entertained.
Bacterial joint infection (ie, septic arthritis) is a medical emergency, as extensive cartilage
damage can occur within hours of infection onset.
Definitive diagnosis is made by joint aspiration and fluid analysis. Joint fluid is evaluated
for color and consistency, and sent to the lab for cell counts with differential, gram stain,
culture, and crystal analysis. Synovial fluid analysis for glucose, protein, and lactate
dehydrogenase (LDH) has limited utility. However, in patients being treated with
antibiotics, such analysis may be useful. In these patients, the resultant Gram stain and
culture may be negative, but a markedly reduced synovial fluid glucose increases the
suspicion for infectious arthritis.
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Elevations of synovial WBC counts above 100,000 per high-powered field (HPF), with
polymorphonuclear cells (neutrophils) comprising more than 90 percent (ie, left shift), is
most predictive of bacterial joint infection, though infection may be present with lower
WBC counts. Additional testing may be warranted based on clinical suspicion and patient
risk factors. Synovial fluid analysis and the septic joint are discussed in greater detail
separately. (See "Septic arthritis in adults" and "Synovial fluid analysis".)
●
Disseminated gonococcal infection (DGI) – DGI can develop in up to 3 percent of
patients infected with Neisseria gonorrhoeae. Most such patients are younger than 40
years, but the condition occurs in both men and women. Presenting features of DGI
include either a triad of abrupt onset of polyarthralgia (non-symmetric), tenosynovitis
(particularly the wrist, fingers, ankles and toes), and painless dermatitis, or an asymmetric
polyarticular or monoarticular purulent arthritis without skin manifestations, in which case
the knee is the most common site. Neisseria gonorrhoeae is one of many organisms that
can cause knee pain due to infection and inflammation. (See "Disseminated gonococcal
infection".)
●
Systemic rheumatic disease – Systemic rheumatic disease is a group of systemic
autoimmune diseases that include: rheumatoid arthritis (RA), systemic lupus
erythematosus (SLE), Sjögren's syndrome, systemic sclerosis, polymyositis, and
dermatomyositis. RA is the most prevalent disease in this group. The presence of systemic
symptoms, such as fevers, chills, night sweats, fatigue, or unintentional weight loss
suggests infection, systemic disease, or cancer. Therefore, in these patients a more
general history and a thorough physical examination should be performed looking for
causes other than primarily musculoskeletal ones. Additional lab testing and diagnostic
imaging may be necessary. (See 'Bone tumors' below and "Clinical manifestations of
rheumatoid arthritis" and "Clinical manifestations of Sjögren's syndrome: Extraglandular
disease" and "Clinical manifestations of Sjögren's syndrome: Exocrine gland disease" and
"Clinical manifestations of dermatomyositis and polymyositis in adults" and "Clinical
manifestations and diagnosis of systemic sclerosis (scleroderma) in adults" and "Clinical
manifestations and diagnosis of systemic lupus erythematosus in adults", section on
'Clinical manifestations'.)
RA and SLE typically cause symmetric polyarthralgia or polyarthritis that may include
bilateral knee pain and swelling. Over 65 to 90 percent of patients with SLE have arthritis,
arthralgias or both. Any patient presenting with polyarticular, symmetric, or migrating
pain, joint swelling, systemic symptoms (fever), or a positive family history may need a
workup for a systemic rheumatic disease.
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Non-traumatic conditions NOT associated with joint effusion — For many patients with
knee pain there is no association with acute trauma and no history or clinical findings of a knee
effusion. In these patients, the first step is to determine if the pain is exacerbated by activity.
Some of the conditions listed below may cause some localized swelling, or an intermittent
effusion, but nearly always this occurs with activity. It is important to ask patients that do not
participate in regular physical exercise or labor if something in their day-to-day activity has
changed (new job, recent vacation, recent work around the house, etc). The second and more
important step is to pinpoint the location of the pain, if possible.
The differential diagnosis for knee pain unrelated to acute trauma or joint effusion is extensive,
and therefore, the history and physical examination should be used to categorize the pain
anatomically and narrow the list of potential diagnoses. A table summarizing the major
diagnoses and their distinguishing features, and organized by pain location, is provided (
table 3).
In summary, the key questions when evaluating these patients include:
●
Is this an acute or chronic problem (six weeks is the standard threshold for chronic knee
pain)?
●
Has your activity level changed significantly in the three months leading up to the onset of
pain?
●
Using a single finger, can you point to the area where the pain is focused?
For the conditions listed below, joint aspiration and serum laboratory studies are rarely
indicated, and radiographs are often unnecessary for making the diagnosis.
Anterior knee pain — Pain at the anterior knee is the most common complaint among
patients presenting with atraumatic knee pain without an effusion. Such pain often stems from
a specific structure and therefore the patient can either "point with one finger" to the painful
site, or the clinician can recreate the pain with focused palpation. The conditions causing such
pain include Osgood-Schlatter disease, Hoffa's fat pad syndrome, patellar and quadriceps
tendinopathy (tendinosis), bursitis, and plica syndrome. Important structures to palpate in
patients with anterior pain include the patella, patellofemoral joint, patellar tendon, tibial
tubercle, and quadriceps tendon (
●
picture 2).
Osgood-Schlatter disease – Pain from Osgood-Schlatter disease is caused by tibial
tubercle apophysitis at the insertion of the patellar tendon. The condition is most common
in active older children and adolescents, but some adults may experience ongoing pain
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after the apophysis has fused. Pain and tenderness are localized to the tibial tubercle (
figure 1 and
figure 2 and
picture 3). Pain increases with activity, particularly
jumping and running. Poor flexibility of the quadriceps, and possibly the hip flexors, may
be noted. (See "Osgood-Schlatter disease (tibial tuberosity avulsion)".)
●
Hoffa's fat pad syndrome – The infrapatellar (ie, Hoffa's) fat pad (IFP) is a highly
innervated and vascularized extra-articular structure located distal to the patella and
directly beneath the patellar tendon. Edema within the fat pad can be painful and has
been implicated in patellofemoral maltracking; patients with a diagnosis of patellofemoral
pain (PFP) should be evaluated for possible IFP involvement [6]. IFP-related pain generally
presents as anterior knee pain distal to the patella. It is often made worse by sprinting
activities or squatting, and shares historical characteristics with patellar tendinopathy and
PFP.
While no special tests are available to diagnose IFP, the physical examination may help to
distinguish it from alternative diagnoses. Knee inspection is usually unremarkable, but
inflammation of the IFP may be noted as asymmetric swelling of the patellar tendon. IFP
syndrome should not cause visible maltracking of the patella during knee flexion or
extension. Maneuvers that impinge the IFP, such as squatting or direct downward
pressure on the patellar tendon, reproduce the patient’s anterior knee pain. Tenderness
with palpation deep to the patellar tendon on either side, but not at its insertion, suggests
inflammation and edema of the IFP [7]. Musculoskeletal ultrasound can be used to
demonstrate that the patellar tendon, bursa, and other adjacent structures appear
normal, and may reveal signs suggestive of IFP pathology. (See "Musculoskeletal
ultrasound of the knee".)
●
Quadriceps and patellar tendinopathy – The distal quadriceps tendon is a conjoined
tendon of the vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris
muscles. As it proceeds distally, the quadriceps tendon envelops the patella and becomes
the patellar tendon distally, inserting on the anterior tibial tubercle. Both the quadriceps
and patellar tendon are susceptible to many of the same conditions and injuries. Explosive
movements involving knee extension, such as jumping, running, or squatting (eccentric
stress) reproduce the pain associated with both quadriceps and patellar tendinopathy.
Quadriceps tendinopathy, the more common condition, characteristically causes pain
proximal to the superior patellar pole. Physical examination findings include focal pain
with resisted knee extension and often some atrophy of the quadriceps muscle (typically
the vastus medialis) on the involved side in comparison with the unaffected leg. Focal
tenderness with direct palpation at, or just proximal to, the superior patellar pole is
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characteristic. In contrast, patellar tendinopathy causes pain distal to the patella. Focal
tenderness at or just distal to the inferior patellar pole is common. (See "Quadriceps
muscle and tendon injuries", section on 'Quadriceps and patellar tendinopathy'.)
The quadriceps and patellar tendons are visualized readily with ultrasound, which can be
used as an adjunct to the physical examination for diagnosing tendinopathy.
Tendinopathic changes visualized on ultrasound may include loss of the normal fibrillar
structure of the tendon with reduced echogenicity, tendon thickening, and possibly calcific
tendinopathy. (See "Musculoskeletal ultrasound of the knee".)
●
Bursitis – Acute prepatellar or superficial infrapatellar bursitis presents with localized
redness, swelling, and marked tenderness anterior to the patella or patellar tendon. The
condition is usually associated with a history of direct trauma or repetitive pressure
(prolonged kneeling) at the patellar region but may also be crystal-induced or due to a
bacterial infection. Examination reveals pre-patellar swelling and edema between the skin
and the patella. Ultrasound examination can be used to assess the anatomic relations of
the above structures, and the exact location of bursitis. Care should be taken to not
compress the superficial structures when performing the examination. The motion and
stability of the knee joint itself remain unaffected by bursitis. (See "Knee bursitis" and
"Musculoskeletal ultrasound of the knee".)
●
Plica syndrome – Individuals who have sustained trauma to the medial peripatellar area
or dislocations or subluxations of the patella may develop thickening of the medial
patellar plica [8]. This condition can also develop chronically from overuse, particularly in
runners with some degree of genu valgus ("knock knees"). A thickened medial plica may
catch at the medial edge of the patella or the medial femoral condyle causing localized
anteromedial knee pain that increases with movement, and possibly chondral injury.
Examination reveals thickening of the plica (palpable in most patients) with focal
tenderness at the medial underside of the patella. Ultrasound can be used to visualize
thickened plica tissue. A useful examination maneuver is the medial patellar plica test (
figure 3). (See "Plica syndrome".)
The causes of anterior knee pain listed above are often readily diagnosed by history and
examination. The causes listed below—patella subluxation, PFP, chondromalacia patella, and
patellar stress fracture—present without acute trauma or joint effusion, and do not lend
themselves to pinpoint localization.
●
Chronic patella dislocation or subluxation – Patients with a history of patellar
dislocation have damaged the medial patellofemoral ligament and thus are at increased
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risk for recurrent or chronic subluxation and dislocation (
figure 4). These patients
typically describe anteromedial patellar discomfort and a sensation of the knee snapping
or giving way during activity. Examination often reveals atrophy of the vastus medialis and
a positive apprehension test (
figure 5). Individuals with hypermobility disorders, such
as Ehlers-Danlos Syndrome, are at risk for chronic patella subluxation. (See "Recognition
and initial management of patellar dislocations".)
●
Patellofemoral pain (PFP) – PFP is a frequently encountered overuse disorder that
involves the patellofemoral region and often presents as anterior knee pain. PFP is
diagnosed primarily from the history and is characterized by pain around or behind the
patella that cannot be attributed to another discrete intra-articular (eg, meniscus tear) or
peripatellar (eg, patellar tendinopathy) pathology. PFP is aggravated by one or more
activities that involve loading the patellofemoral joint during weight bearing on a flexed
knee. Common historical features include vague, poorly localized anterior knee pain
(usually "under" or around the patella) that is made worse with squatting, running,
prolonged sitting (theater sign), or going up or down stairs. Mechanical symptoms (eg,
locking, catching) and the presence of an effusion are NOT associated with PFP. Many
people with PFP report instability or their knee "giving out", which stems from pain
causing reflex inhibition of the quadriceps. It bears emphasis that patellar instability and
ligamentous injury of the knee should be ruled out by examination before ascribing the
patients symptoms to PFP. Ultrasound can be used to assess peripatellar structures of the
knee and to help rule out other diagnoses. However, there are no ultrasound-specific
changes or criteria for diagnosing PFP. (See "Patellofemoral pain" and "Musculoskeletal
ultrasound of the knee".)
●
Chondromalacia patella – Chondromalacia patella is a cause of peripatellar pain and the
term is commonly used interchangeably with PFP. However, chondromalacia patella is a
distinct radiologic diagnosis defined by the presence of pathologic changes in the articular
cartilage on the underside of the patella, such as softening, erosion, and fragmentation
[9]. The clinical history and examination findings are similar to PFP, but an effusion may
also be present if articular cartilage damage is sufficiently severe. The articular damage is
usually secondary to a prior injury or chronic maltracking of the patella in the trochlear
groove. MRI is needed to make the diagnosis but is usually unnecessary as treatment is
similar to that for PFP.
●
Patella stress fracture – Patella stress fractures develop after repeated application of
submaximal stress leading to cortical disruption and pain. These fractures are seen in
highly active individuals participating in explosive jumping or plyometric activities, and
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does not occur in sedentary individuals or "weekend warriors." Often, there is an abrupt
increase in the volume or intensity of exercise or athletic training several weeks prior to
the onset of pain. Although rare, patella stress fractures are considered to be at high risk
for nonunion and should be referred to a provider with expertise in musculoskeletal
medicine [10]. The history and examination findings are often nonspecific in the early
stages, but pain becomes more localized to the patella as the injury progresses.
Ultrasound can be used to evaluate for acute patellar fracture or bipartite patella;
however, it is not sensitive or specific for stress fracture. MRI is typically needed to make a
definitive diagnosis. (See "Overview of stress fractures" and "Approach to chronic knee
pain or injury in children or skeletally immature adolescents", section on 'Patellar stress
fracture'.)
Medial knee pain — Medial knee pain unrelated to trauma or a joint effusion may be due to a
degenerative tear of the medial meniscus or to other conditions. Important structures to
palpate include the medial joint line, medial (tibial) collateral ligament, and pes anserine bursa.
●
Degenerative medial meniscal tear – Degenerative medial meniscal tears are common
in older patients, as the medial compartment of the knee absorbs the most force during
walking, running, and squatting (
figure 6 and
figure 7). Although a common finding
on MRI, degenerative meniscal tears (both medial and lateral), are often asymptomatic.
Findings that suggest a meniscal tear is the source of pain include medial or diffuse knee
pain, mechanical symptoms (catching, locking, inability to extend the knee completely),
swelling (especially after activity), and increased pain with squatting. Examination findings
consistent with a meniscal tear include medial joint line tenderness (especially posterior to
the medial collateral ligament), positive McMurray test, and a positive Thessaly test. It is
important to ask whether the pain elicited during a provocative maneuver of the knee (eg,
McMurray test) is the same as the pain that the patient has been experiencing and caused
them to seek medical attention. A thorough history and examination are typically
sufficient to make the diagnosis, and advanced imaging is generally unnecessary. (See
"Meniscal injury of the knee".)
●
Saphenous nerve entrapment – The saphenous nerve is the largest cutaneous branch of
the femoral nerve (
figure 8). It traverses the adductor canal and its infrapatellar branch
innervates the skin over the medial and anterior portion of the knee. Entrapment at the
adductor canal, or anywhere along the nerve’s path thereafter, can cause medial knee pain
[11]. Such pain is characterized by allodynia (pain provoked by a typically benign stimulus)
and radiation along the course of the saphenous nerve, and is worsened by palpation or
tapping at the site of entrapment (Tinel's maneuver). Pain is generally NOT related to
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activity and the person may complain of positional pain. Consider this diagnosis in
patients with chronic medial knee pain that is not consistently associated with activity,
refractory to treatment, and associated with unremarkable imaging studies. A skilled
sonographer can perform an ultrasound examination of the saphenous nerve. The
pathologic nerve may be thickened and/or surrounded by fluid. A saphenous nerve block
can relieve symptoms and confirm the diagnosis.
●
Pes anserine bursitis – The pes anserine tendons and underlying bursa are readily
identified, and should be palpated in patients presenting with anterior or medial knee
pain. The pes anserine is located on the proximal anteromedial aspect of the tibia and is
the common tendinous insertion of the sartorius, gracilis, and semi-tendinosis muscles (
picture 4). Pain from pes anserine bursitis is usually of insidious onset and located on
the medial side of the knee. It is worse with exercise (especially running) or ascending
stairs. Pes anserine bursitis is common in older patients with osteoarthritis and less
common among younger individuals. Examination may reveal tenderness over the medial
joint line, similar to a medial meniscal injury, for which it is commonly mistaken. However,
the point of maximum tenderness in patients with pes anserine bursitis is at or near the
insertion of the pes anserine tendon on the tibia, which is anterior and distal to the medial
joint line. While there may be focal swelling of the bursa at the tendon insertion point,
knee swelling or effusion is NOT caused by pes anserine bursitis. Although the pes
anserine bursa is readily seen on ultrasound, such evaluation is generally not needed for
diagnosis or treatment. (See "Knee bursitis".)
Lateral knee pain — Lateral knee pain unrelated to trauma or a joint effusion may be due to
iliotibial band syndrome, a degenerative tear of the lateral meniscus, or to other conditions.
Important structures to palpate include the lateral joint line, lateral femoral condyle, and the
lateral collateral ligament (LCL).
●
Iliotibial band syndrome (ITBS) – Chronic atraumatic lateral knee pain is often caused by
ITBS. The ITB is a fibrous band that runs longitudinally along the lateral aspect of the thigh
from its origin at the iliac crest to its insertion on the proximal tibia (at Gerdy’s tubercle) (
figure 9). An aching or burning pain and focal tenderness at the site where the band
courses over the lateral femoral condyle (pain is not at the insertion on the tibia or at the
lateral joint line) characterizes ITBS, which occurs predominately in runners, but may
develop in cyclists due to overuse or improper seat height. The history may include
downhill running or walking, or running the same direction on cambered roads (most
roads have a slight slant to them eliciting a functional leg length discrepancy if one runs
the same direction on the same road consistently), all of which aggravate the ITB. A
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suggestive history, focal tenderness at the lateral femoral condyle, and a positive Noble
compression test suggest the diagnosis. (See "Iliotibial band syndrome".)
Ultrasound examination can be helpful for diagnosing ITBS. Tendinopathic changes,
including loss of the normal fibrillar structure of the tendon, along with reduced
echogenicity and tendon thickening, can be seen. Furthermore, dynamic assessment of
the ITB during knee flexion and extension may reveal "snapping or friction" of the tendon
over the lateral femoral condyle. (See "Musculoskeletal ultrasound of the knee".)
●
Degenerative lateral meniscal tear – Degenerative lateral meniscal tears are less
common than medial meniscal tears, but the clinical presentation and examination
findings are similar. Examination should include palpation of the ITB over the lateral
femoral condyle and Noble’s compression test to rule out ITBS. (See 'Medial knee pain'
above and "Meniscal injury of the knee".)
Posterior knee pain — Posterior knee pain unrelated to trauma or a joint effusion may be due
to popliteal artery aneurysm or entrapment, popliteal (Baker's) cyst, or tendinopathy
(tendinosis). The important area to palpate is the popliteal fossa (both for a mass and a pulse).
●
Popliteal artery aneurysm – Generally seen in older individuals with risk factors for
cardiovascular disease (eg, hypertension, smoking), popliteal artery aneurysms may
present with chronic or acute posterior knee pain (
picture 5 and
figure 10). Small
aneurysms may be asymptomatic, but symptomatic aneurysms can present with signs of
claudication or acute limb-threatening ischemia from arterial thrombosis. A large pulsatile
mass noted in the popliteal fossa is consistent with this diagnosis. Ultrasound can be used
to look for an aneurysm in the popliteal fossa. Comparison to the contralateral side is
easily done. If this diagnosis is possible, patients should be referred for appropriate
advanced diagnostic imaging. A substantial percentage of patients with a popliteal artery
aneurysm have an abdominal aortic aneurysm and screening is warranted. (See "Popliteal
artery aneurysm".)
●
Popliteal artery entrapment – Unlike popliteal artery aneurysm, popliteal artery
entrapment is a rare cause of posterior knee pain typically seen in athletic individuals
(men more often than women) that is NOT suggestive of underlying cardiovascular
disease (
picture 5). Patients typically complain of a deep pain in the calf or popliteal
fossa, and claudication type symptoms during vigorous activities involving repeated ankle
dorsiflexion and plantarflexion [12]. Patients are typically asymptomatic at rest with a
normal resting physical examination. Awareness of this entity and a high index of
suspicion are important because tailored imaging studies are required to make the
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diagnosis. (See "Calf injuries not involving the Achilles tendon", section on 'Popliteal artery
entrapment'.)
●
Popliteal "Baker's" cyst – A popliteal (or Baker's) cyst often presents as posterior knee
pain and swelling, which can be abrupt or insidious in onset (
picture 6). The swelling is
localized to the posterior capsule and is not a true joint effusion; however, it is typically
joint fluid that is contained in the cyst. Swelling usually worsens after exercise, especially
activities involving repetitive knee flexion or squatting. Some patients have cyst formation
without knee pain. Examination commonly reveals a palpable, non-pulsatile cystic
structure in the popliteal fossa during knee extension that disappears with knee flexion.
Ultrasound examination reveals a fluid-filled mass at the intersection of the medial
gastrocnemius and semimembranosus tendons. (See "Popliteal (Baker's) cyst".)
●
Popliteus tendinopathy – The popliteal tendon can be injured, along with other
structures in the posterolateral corner, during acute trauma. However, popliteal
tendinopathy (or tendinosis) can develop chronically, most often in people who do a lot of
downhill running or walking. Pain is described as a deep ache or sharp pain exacerbated
by performing downhill activities. Typically, pain can be elicited by palpating the popliteal
tendon origin just anterior to the lateral femoral condyle and LCL. This is done more easily
if the patient crosses their legs in a "figure-of-four" position. The primary function of the
popliteus is tibial internal rotation; therefore, symptomatic patients experience pain with
resisted internal rotation (Garrick's test) or passive external rotation of the tibia. (See "Calf
injuries not involving the Achilles tendon", section on 'Popliteus tendinopathy'.)
BONE TUMORS
Primary bone tumors such as osteosarcoma, chondrosarcoma, and Ewing's sarcoma, as well as
metastatic tumors to bone, are rare, but important causes of knee pain. Patients complain of
localized low-level pain, with possible swelling, in the area of the tumor. A joint effusion may be
present if the tumor is intra-articular. Systemic symptoms, such as fevers, chills, night sweats,
and unintentional weight loss, may be present but are not universal findings. Pain that is worse
at night is a concerning finding that should prompt an in-depth workup. Plain radiographs are
helpful to look for bony tumors. (See "Bone tumors: Diagnosis and biopsy techniques", section
on 'Clinical presentation'.)
REFERRED PAIN
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Patients with pain that originates from disorders of the back, sacroiliac joint, or hip may present
with knee pain referred from the actual source. The fifth lumbar (L5) nerve root and sacroiliac
joint can refer pain to the popliteal space. The first sacral (S1) nerve root, hip joint, trochanteric
bursa, and femur can refer pain along the lateral thigh to the lateral aspect of the knee [13].
Patients with referred pain typically struggle to localize or describe their symptoms. The knee
examination lacks focal tenderness or inflammatory changes, and flexion and extension of the
knee are normal, or symmetric with the asymptomatic joint.
OTHER INFREQUENT CAUSES OF KNEE PAIN
These rare causes of knee pain should be considered on the differential of persistent
unexplained knee pain, especially when objective findings of the knee are vague.
Systemic conditions — A number of systemic conditions may present with musculoskeletal
manifestations, including arthralgias and knee pain, early in the disease course. These include
thyroid disease, primary hyperparathyroidism, hemochromatosis, viral infection, syphilis, and
sarcoidosis. However, these are rare causes of knee pain.
Medication side effects — Systemic glucocorticoids have been linked to osteonecrosis
(avascular necrosis of bone), which is discussed separately. Two high-risk groups for
osteonecrosis include renal transplant patients and persons with systemic lupus
erythematosus. The presenting symptom is insidious unilateral or bilateral knee pain,
exacerbated with weight bearing activity [14].
Statin induced myalgias are well known, however, cases of knee pain associated with the use of
statins in combination with phosphodiesterase-5 inhibitor have been reported [15].
Fluoroquinolones [16] and retinoids [17] and have been reported to cause knee pain in children
and adolescents.
Vaccinations — There are several case reports of new onset rheumatoid arthritis with knee
involvement in adults after receiving an anthrax vaccine [18]. In addition, there is a case report
of right knee reactive arthritis two days following tetanus vaccination [19].
IMAGING
Diagnostic imaging is used as an adjunct to the history and physical examination when
evaluating the adult with knee pain. The suspected clinical diagnoses determine the need for
imaging and appropriate study selection. Following acute trauma, imaging typically begins with
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plain radiographs (
Approach to the adult with unspecified knee pain - UpToDate
image 1). In patients with non-traumatic knee pain associated with an
effusion, poor response to a treatment plan, or when the diagnosis is unclear, advanced
diagnostic imaging may be useful. (See "Approach to the adult with knee pain likely of
musculoskeletal origin", section on 'Imaging in the evaluation of acute knee pain'.)
Magnetic resonance imaging (MRI) is the best imaging technique for diagnosis of soft tissue
knee injuries (eg, ligament, meniscus). However, for most causes of knee pain, an MRI is
unnecessary to make the correct diagnosis. Radiologic assessment of patients with acute knee
pain is reviewed in detail separately. (See "Radiologic evaluation of the acutely painful knee in
adults".)
Ultrasound has gained popularity for evaluating musculoskeletal conditions, and it offers many
advantages in diagnosing certain knee conditions. Ultrasound permits detailed, real-time,
evaluation of the soft tissues, collateral ligaments, and tendons surrounding the knee, and is
more sensitive and specific for detecting a knee effusion compared with manual techniques. In
addition, ultrasound enables the clinician to perform dynamic evaluation of the knee (ie,
visualizing knee structures while the knee joint is manipulated), and to compare findings with
the contralateral knee. (See "Musculoskeletal ultrasound of the knee".)
Dual-energy computed tomography (DECT) examination is an emerging imaging modality that
can identify urate deposits in articular and periarticular locations and can distinguish urate
from calcium deposition. (See "Clinical manifestations and diagnosis of gout", section on
'Imaging'.)
Additional ultrasound resources — Instructional videos demonstrating proper performance
of the ultrasound examination of the knee and related pathology can be found at the website of
the American Medical Society for Sports Medicine: sports US knee pathology. Registration must
be completed to access these videos, but no fee is required.
SOCIETY GUIDELINE LINKS
Links to society and government-sponsored guidelines from selected countries and regions
around the world are provided separately. (See "Society guideline links: Knee pain".)
SUMMARY AND RECOMMENDATIONS
●
The differential diagnosis for knee pain is complex and obtaining a clear history remains
essential for diagnosis. The following flow chart provides an overview of how to approach
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the diagnosis of knee pain in the adult (
algorithm 1). Important elements of the history
include whether trauma contributed to the development of knee pain and whether pain
increases with activity, and if so what sort of activity. Information from the history helps
the clinician to distinguish among five diagnostic categories:
• Acute knee pain following recent trauma or overuse
• Atraumatic knee pain associated with joint effusion
• Atraumatic knee pain NOT associated with joint effusion
• Referred knee pain
• Uncommon causes of knee pain
Key questions to ask the adult presenting with undifferentiated knee pain are reviewed in
the text. (See 'History overview and diagnostic categories' above.)
●
The physical examination of any joint is classically divided into inspection, palpation, range
of motion testing, strength and neurovascular testing, and special maneuvers to assess
for specific diagnoses. Special tests are selected based upon the most likely diagnostic
category, which is based in turn upon the history. Detection of a knee joint effusion is an
important part of the examination. The knee examination is described in detail separately.
(See "Physical examination of the knee" and 'Physical examination of the knee' above.)
●
Key steps for determining the underlying cause of knee pain in the adult include the
following:
• Distinguish between acute and chronic pain.
• Distinguish between traumatic and non-traumatic pain.
• Determine whether a joint effusion is present.
• Determine the location of the pain.
Each step is discussed in the text. Once a history and examination are performed, and the
steps outlined here are completed, the clinician will have narrowed the differential
diagnosis to a small number of potential conditions. (See 'Initial steps to categorizing knee
pain' above.)
●
Common causes of knee pain following acute, low-energy trauma include the following:
• Medial or lateral collateral ligament tear
• Anterior cruciate ligament tear
• Meniscus tear
• Patella dislocation or significant subluxation
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• Patella tendon tear
• Intra-articular fracture
• Osteochondral defect
Important distinguishing features of these diagnoses are reviewed separately. (See 'Acute
knee pain associated with trauma' above.)
●
The differential diagnosis of non-traumatic knee pain associated with an effusion can be
narrowed based on the association with activity. Important, common causes of nontraumatic knee pain that increase acutely with activity include articular cartilage injury and
osteoarthritis. (See 'Non-traumatic conditions associated WITH a joint effusion' above.)
●
Knee pain associated with a joint effusion, despite the absence of any trauma or activity
that exacerbates symptoms, is a concerning finding, and indicates the need for a more
extensive workup. In addition to a careful history and examination, plain radiographs and
knee joint aspiration are often necessary. Important causes of non-traumatic knee pain
that is not associated with activity include crystal arthropathy (eg, gout), infectious (septic)
arthritis, disseminated gonococcal infection, and systemic rheumatic disease. (See
'Conditions NOT related to activity' above.)
●
For the many patients with knee pain not associated with acute trauma and without a
knee effusion, the first step is to determine if the pain is exacerbated by activity. Some of
these conditions may cause localized swelling, or an intermittent effusion, but nearly
always this occurs with activity. It is important to ask patients that do not participate in
regular physical exercise or labor if something in their day-to-day activity has changed
(new job, recent vacation, recent work around the house, etc). The second, crucial step is
to pinpoint the location of the pain. (See 'Non-traumatic conditions NOT associated with
joint effusion' above.)
• Causes of anterior knee pain unrelated to acute trauma or a joint effusion include
Osgood-Schlatter disease, Hoffa’s fat pad syndrome, quadriceps and patellar
tendinopathy, bursitis, plica syndrome, patellofemoral pain, and several conditions
affecting the patella (eg, chronic subluxation, stress fracture).
• Causes of medial knee pain unrelated to acute trauma or a joint effusion include
degenerative medial meniscal tear, saphenous nerve entrapment, and pes anserine
bursitis.
• Causes of lateral knee pain unrelated to acute trauma or a joint effusion include
iliotibial band syndrome and degenerative lateral meniscal tear.
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• Causes of posterior knee pain unrelated to acute trauma or a joint effusion include
popliteal artery aneurysm or entrapment, popliteal (Baker's) cyst, and popliteus
tendinopathy.
●
Other, less common causes of knee pain, including bone tumors and referred pain, are
discussed briefly in the text. (See 'Bone tumors' above and 'Referred pain' above and
'Other infrequent causes of knee pain' above.)
ACKNOWLEDGMENT
The author and editors acknowledge Ron Anderson, MD, and Bruce Anderson, MD, both of
whom contributed to earlier versions of this topic review.
Use of UpToDate is subject to the Subscription and License Agreement.
REFERENCES
1. Jinks C, Jordan K, Croft P. Measuring the population impact of knee pain and disability with
the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Pain 2002;
100:55.
2. Nguyen US, Zhang Y, Zhu Y, et al. Increasing prevalence of knee pain and symptomatic
knee osteoarthritis: survey and cohort data. Ann Intern Med 2011; 155:725.
3. Razek AA, Fouda NS, Elmetwaley N, Elbogdady E. Sonography of the knee joint(). J
Ultrasound 2009; 12:53.
4. National Clinical Guideline Center. Osteoarthritis: care and management in adults. National
Institute for Health and Clinical Excellence: Guidance, London 2014. http://www.ncbi.nlm.ni
h.gov.ezproxy.umng.edu.co/pubmed/25340227 (Accessed on September 24, 2016).
5. Zhang W, Doherty M, Peat G, et al. EULAR evidence-based recommendations for the
diagnosis of knee osteoarthritis. Ann Rheum Dis 2010; 69:483.
6. Subhawong TK, Eng J, Carrino JA, Chhabra A. Superolateral Hoffa's fat pad edema:
association with patellofemoral maltracking and impingement. AJR Am J Roentgenol 2010;
195:1367.
7. Dragoo JL, Johnson C, McConnell J. Evaluation and treatment of disorders of the
infrapatellar fat pad. Sports Med 2012; 42:51.
8. Schindler OS. 'The Sneaky Plica' revisited: morphology, pathophysiology and treatment of
synovial plicae of the knee. Knee Surg Sports Traumatol Arthrosc 2014; 22:247.
https://www-uptodate-com.ezproxy.umng.edu.co/contents/approach-to-the-adult-with-unspecified-knee-pain/print?search=dolor de rodilla&source=s…
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9. Pihlajamäki HK, Kuikka PI, Leppänen VV, et al. Reliability of clinical findings and magnetic
resonance imaging for the diagnosis of chondromalacia patellae. J Bone Joint Surg Am
2010; 92:927.
10. Behrens SB, Deren ME, Matson A, et al. Stress fractures of the pelvis and legs in athletes: a
review. Sports Health 2013; 5:165.
11. Morganti CM, McFarland EG, Cosgarea AJ. Saphenous neuritis: a poorly understood cause
of medial knee pain. J Am Acad Orthop Surg 2002; 10:130.
12. Rajasekaran S, Finnoff JT. Exertional Leg Pain. Phys Med Rehabil Clin N Am 2016; 27:91.
13. Georgoulis AD, Papageorgiou CD, Moebius UG, et al. The diagnostic dilemma created by
osteoid osteoma that presents as knee pain. Arthroscopy 2002; 18:32.
14. Chan KL, Mok CC. Glucocorticoid-induced avascular bone necrosis: diagnosis and
management. Open Orthop J 2012; 6:449.
15. Pujalte GG, Acosta L. Bilateral knee and intermittent elbow pain in a competitive
archer/hunter: phosphodiesterase-5-inhibitor-statin interaction? Clin J Sport Med 2014;
24:e52.
16. Gough AW, Kasali OB, Sigler RE, Baragi V. Quinolone arthropathy--acute toxicity to
immature articular cartilage. Toxicol Pathol 1992; 20:436.
17. Luthi F, Eggel Y, Theumann N. Premature epiphyseal closure in an adolescent treated by
retinoids for acne: an unusual cause of anterior knee pain. Joint Bone Spine 2012; 79:314.
18. Vasudev M, Zacharisen MC. New-onset rheumatoid arthritis after anthrax vaccination. Ann
Allergy Asthma Immunol 2006; 97:110.
19. Sahin N, Salli A, Enginar AU, Ugurlu H. Reactive arthritis following tetanus vaccination: a
case report. Mod Rheumatol 2009; 19:209.
Topic 253 Version 39.0
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GRAPHICS
Approach to knee pain in the adult
ED: emergency department; ACL: anterior cruciate ligament; PCL: posterior cruciate ligament; MCL: medial col
rheumatoid arthritis.
* Joint aspiration and fluid analysis are important for diagnosing these conditions.
¶ Includes local joint infection or disseminated infection (eg, gonococcal).
Δ Osteoarthritis can cause diffuse or focal pain in any of several locations.
◊ Symptomatic degenerative meniscal tears may or may not be associated with a small effusion.
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Graphic 111806 Version 1.0
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Acute traumatic knee pain in active adults: Causes and distinguishing features
Condition
Mechanism &
historical
features
Common
symptoms
Key
examination
findings
Additional
comments
Significant knee swelling
Anterior cruciate
ligament (ACL) tear
Sudden change in
direction or
landing from a
jump (noncontact injury
most common)
Knee feels
unstable
Substantial
effusion
Pain variable
Positive Lachman,
anterior drawer, &
pivot shift tests
Knee pain and
swelling
Substantial
effusion
Knee is popping,
locking, catching,
not moving
properly, or feels
unstable
Joint line
tenderness
Female athletes at
higher risk
Audible "pop" at
time of injury
Rapid swelling
Large meniscus
tear
Sudden, forceful
twisting of the
knee with foot
planted
Tearing or
popping
sensation at time
of injury
Knee may not
fully extend &
may give way with
rotation
Pain increases
with squatting or
pivoting
Loss of smooth
passive flexion &
extension
Severity of
symptoms & signs
varies with extent
and location of
tear
May not be able
to achieve full
active flexion or
extension
Positive McMurray
test
Positive bounce
home test
Pain with
compression and
twisting of knee
(eg, positive
Thessaly test)
Intra-articular
fracture
Large valgus
stress on knee,
possibly during
landing from
jump or fall
Knee pain and
swelling
Joint line
tenderness
(usually lateral)
Lateral tibial
plateau most
often affected
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Trauma may be
minor in
osteoporotic
women or elder
men
Ligamentous
instability absent
Aspiration fluid
may be bloody
and contain fat
globules
Rapid swelling
Osteochondral
defect
Vigorous activity
involving sudden
change in
direction and/or
jumping
Knee pain and
swelling (effusion
varies with size of
defect)
Ligamentous
instability absent
(distinguishes
from ACL injury)
Medial femoral
condyle at
greatest risk
Knee "out of
place" (typically
lateral)
Effusion
Patients with
hypermobility
may have
recurrent
dislocation with
milder symptoms
and physical
findings
Immediate pain
and rapid
swelling
Patellar dislocation
Pivoting or
sudden change in
direction
Many reduce
spontaneously
prior to
presentation
Posterior lateral
corner tear
Patients may not
recall trauma
Posterior cruciate
ligament (PCL) tear
Patellar tendon
tear
Patella may be
dislocated or
subluxed
Tenderness often
present along
medial patellar
border
Posterior knee
pain and
instability
Focal tenderness
at posterior lateral
corner of knee
Pain at posterior
knee with
pivoting
Positive dial test
Direct blow to
proximal anterior
tibia
Posterior knee
pain
Positive sag sign
Sudden forceful
flexion of a knee
Knee pain and
swelling
If recalled,
trauma may
involve blow to
proximal anterior
tibia
Imaging studies
(eg, CT) needed
for diagnosis
Instability (may
not be present):
knee feels like it
may hyperextend
Positive posterior
drawer test
Infrapatellar
swelling &
ecchymosis
Can occur from
direct trauma or
overuse
More common
among young
females
May occur with
ACL or LCL injury
History may be
unclear: Patient
may not associate
current
symptoms with
past trauma
Anabolic steroid
use and
quinolone
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already flexed 60
degrees or more
Cannot extend
knee
Tenderness (and
possible tendon
defect) at inferior
patellar border
antibiotics
increase risk
Painful knee
extension with
partial tear
Unable to extend
knee with
complete tear
Quadriceps
tendon tear
Sudden fall
backward while
foot is fixed and
knee flexed;
athlete tackled
while in this
position
(American
football; rugby)
Anterior knee
pain and swelling
Cannot extend
knee
Difficulty bearing
weight
Suprapatellar
swelling &
ecchymosis
Tenderness (and
possible tendon
defect) at superior
patellar border
Uncommon but
can occur
spontaneously in
athletes over 40
Painful knee
extension with
partial tear
Unable to extend
knee with
complete tear
Knee
(tibiofemoral)
dislocation
Typically high
energy trauma
involving direct
blow to anterior
knee causing
hyperextension
Can occur in
obese individuals
who fall
Knee pain,
swelling, and
instability
May reduce
spontaneously
prior to
presentation
Substantial
effusion
Ligamentous
instability in
multiple planes
Dangerous injury
that can
compromise
blood flow to leg
Limited knee swelling
Small or moderate
meniscus tear
Sudden forceful
twisting of the
knee with foot
planted
Tearing or
popping
sensation at time
of injury
Knee is popping,
locking, catching,
not moving
properly, or feels
unstable
Pain increases
with squatting or
pivoting
Joint line
tenderness
Positive McMurray
test
Pain with
compression and
twisting of knee
Severity of
symptoms & signs
varies with extent
and location of
tear
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(eg, positive
Thessaly test)
Medial collateral
ligament (MCL)
strain
Twisting of leg or
direct blow to
lateral knee
creating valgus
force
Medial knee pain
Lateral collateral
ligament (LCL)
strain
Twisting of leg or
direct blow to
medial knee
creating varus
force
Lateral knee pain
Patellar
subluxation
History as above
for patellar
dislocation
Anterior knee
pain
Effusion mild or
absent
Crepitation along
superior lateral
corner of patella
Hypermobile
patella
Medial knee feels
unstable with
"cutting" or lateral
movements
Lateral knee feels
unstable with
"cutting" or lateral
movements
Focal tenderness
over MCL
Positive valgus
stress test
Focal tenderness
over LCL
Positive varus
stress test
Apprehension test
may be positive
Partial ACL tear
History as above
for ACL tear
Symptoms as
above but
generally milder
Ligamentous
instability may be
mild or absent
Partial PCL tear
History as above
for PCL tear
Symptoms as
above but
Ligamentous
instability may be
generally milder
mild or absent
Anterior knee
pain, ecchymosis,
Focal patella
tenderness
Patella fracture
Direct trauma to
anterior knee
and swelling
Medial meniscal
tear often
accompanies MCL
tear
LCL tear requires
greater force than
MCL so injuries to
cruciate ligaments
(ACL, PCL) can
occur
Increased risk
with
hypermobility
syndromes
More common
with shallow
patellar groove
Perform plain
radiographs
including sunrise
view
Must assess
integrity of knee
extensor
mechanism and
PCL
Fibular neck or
head fracture
Direct trauma to
lateral knee, or
associated with
severe ankle
Lateral knee pain
Focal tenderness
over proximal
fibula
sprain or fracture
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History of forceful collision, landing, or abrupt change in movement. Abrupt onset of pain, swelling, and
possibly instability.
Graphic 90950 Version 5.0
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Non-traumatic knee pain associated with joint effusion in adults: Common
causes and features
Condition
Mechanism &
historical features
Common
symptoms
Key
examination
findings
Additional
comments
Activity related
Chronic
Mild repetitive
Diffuse knee
Activity
Radiographs
osteochondral
defect
trauma
(running/jumping)
pain worse
with and after
related
effusion
or advanced
imaging
activity
Knee
osteoarthritis
(MRI) needed
for diagnosis
Usually adults 50
years or older
Diffuse knee
pain
Effusion
present
Weight
bearing
Activity-related pain;
Delayed
Ligaments
brief stiffness after
inactivity
swelling (12
to 24 hours
stable;
meniscus
radiographs
show
post activity)
testing
equivocal
Inability to
fully flex or
sclerosis,
osteophytes,
and joint
space
narrowing
extend knee
common
Not activity related
Crystal
Acute knee pain and
Diffuse knee
Erythema,
Joint
arthropathy
effusion
pain and
swelling
warmth,
tenderness,
aspiration
required for
Weight
and swelling
of knee
diagnosis
No trauma or recent
activity
bearing can
be difficult
Knee flexion
Serum uric
acid level
limited by
effusion and
should not
be used for
pain
diagnosis
Infectious
Acute knee pain and
Diffuse knee
Erythema,
Medical
arthritis
effusion
pain and
swelling
warmth,
tenderness,
emergency
Weight
and swelling
of knee
No trauma or recent
activity
bearing can
be difficult
Knee flexion
Joint
aspiration
critical for
diagnosis
limited by
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effusion and
pain
Systemic
rheumatic
Include RA, SLE,
Sjögren's syndrome,
Systemic
symptoms
Examination
findings
Consider in
oligoarticular
disease
systemic sclerosis,
spondyloarthropathy,
(fever, night
sweats,
highly
variable
or
polyarticular
polymyositis, and
dermatomyositis
fatigue,
weight loss)
joint disease,
pain with
RA is most prevalent
and
polyarthralgia
swelling,
systemic
common
symptoms,
or a positive
family history
MRI: magnetic resonance imaging; RA: rheumatoid arthritis; SLE: systemic lupus erythematosus.
Graphic 111548 Version 1.0
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Heberden's nodes
Heberden's nodes, appearing as discrete postero-lateral swellings (index finger) or as a dorsal bar (middle
finger) over the DIP joints.
DIP: distal interphalangeal.
Reproduced with permission from: OARSI Online Primer. Edited by Henrotin Y, Hunter D, Kawaguchi H. 2012. Osteoarthritis Research
Society International. (http://primer.oarsi.org).
Graphic 105816 Version 1.0
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Knee pain NOT associated with acute trauma or joint effusion in adults: Causes
and distinguishing features
Condition
Mechanism &
historical features
Common
symptoms
Key
examination
findings
Additional
comments
Anterior knee pain
Conditions with focal pain
Tibial tubercle
Common in athletes in
Pain around
Tenderness at
Apophysitis at
apophysitis
(Osgood
early to mid teens
whose sports involve
tibial tubercle
or inferior
tibial tubercle
or inferior pole
tibial tubercle
(Osgood
Schlatter)
cutting and jumping.
pole of
patella.
of patella.
Schlatter) is far
more common
Often occurs during
growth spurt while
athlete is very active.
Focal swelling
& warmth
directly over
apophysis.
Pain increases with
activity and decreases
Knee stable
with rest.
and motion
normal.
than
apophysitis at
inferior pole of
patella (Sinding
Larsen
Johansson).
Plain
radiographs
show open
apophysis,
often with
fragmentation.
US shows open
apophysis &
fluid over
tuberosity.
Hoffa's fat pad
syndrome
Caused by painful
edema within fat pad.
Anterior knee
pain.
Pain increases
with kneeling,
walking,
squatting, or
running.
Tenderness
along either
May contribute
to
side of patella
tendon (not
patellofemoral
maltracking.
tendon proper).
Asymmetric
swelling
adjacent to
patellar
tendon.
Quadriceps and
patellar
History of overuse,
typically involving
Pain at tendon
or inferior
Tendon tender
at inferior pole
US shows
characteristic
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tendinopathy
sports with jumping or
sprinting and sudden
pole of patella
(patellar
of patella (most
common),
direction change.
tendinopathy)
or superior
along tendon,
at tibial
pole of patella
(quadriceps
tendinopathy)
tuberosity, or
at superior
pole of patella.
Gradual onset of pain
that steadily increases
over time if ballistic
activity continues.
with ballistic
movements
(eg, jumping,
sprinting,
cutting).
Tendon may
feel thick
compared to
normal
(contralateral)
changes of
tendinopathy.
Patellar
tendinopathy
more common
than
quadriceps.
In skeletally
immature,
consider
apophysitis.
one.
Often
associated with
tight
quadriceps
and/or hip
flexors.
Knee motion
normal.
Squat or hop
reproduces
pain.
Prepatellar or
infrapatellar
Swelling develops over
days just anterior or
Pain and
swelling just
Swollen boggy
bursa: Early
US shows fluid
collection; fluid
bursitis
inferior to patella.
anterior to or
swelling
extends into
below patella.
anterior to or
soft tissues as
below patella;
gradually
swelling
increases.
History of continual
pressure on affected
area (eg, laborer
swelling
working while
increases.
kneeling); not typically
associated with acute
trauma, but prior
Overlying skin
erythematous.
puncture wound may
be needed to
rule out septic
bursitis.
Knee motion
be reported.
Plica syndrome
Aspiration may
normal.
History of trauma to
Pain around
Thickened plica
US shows
medial peripatellar
area or
medial patella
that increases
palpable under
medial patella.
thickened plica.
dislocation/subluxation
with
of patella.
movement
Runners with genu
valgus ("knock knees")
(knee flexion
Patella tracks
abnormally
during knee
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g
(
Approach to the adult with unspecified knee pain - UpToDate
)
at risk.
and
extension).
flexionextension.
Audible pop
from medial
patella area
during flexionextension.
Conditions without focal pain
Chronic patella
Pivoting or sudden
Knee "out of
Tenderness
Patients with
dislocation or
change in direction
place"
often present
hypermobility
subluxation
produces acute
(typically
along medial
may have
episodes, which recur.
lateral).
patellar border.
Many
Effusion may
recurrent
dislocation with
episodes
be present
reduce
after acute
spontaneously
prior to
dislocation.
presentation.
milder
symptoms and
physical
findings.
More common
among young
females.
Patellofemoral
pain
History of overuse,
often involving
Diffuse,
anterior peri-
Patellar
undersurface
Patellofemoral
pain accounts
running.
patellar pain.
may be tender
for 70% of
(medial or
outpatient visits
lateral).
for knee pain.
Weak terminal
Structural intra-
knee extension
articular injury
and VMO
must be ruled
atrophy
common.
out if recurrent
effusions or
Knee may feel
"unstable".
Pain increases
with
squatting,
prolonged
sitting,
running
Weak hip
(especially
flexion,
downhill),
climbing or
abduction, &
external
descending
rotation
stairs.
common.
Hamstring
tightness
common.
Patellofemoral
compression
test may be
positive
unusual
findings (eg,
abnormal knee
motion or laxity
detected)
present.
Patient may
describe knee
weakness (or
"giving out"),
likely due to
reflex inhibition
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positive.
Normal knee
of quadriceps
motion.
from pain.
Effusion rare.
Chondromalacia
patella presents
with similar
history and
examination,
but advanced
imaging reveals
pathologic
changes.
Chondromalacia
As with patellofemoral
As with
As with
MRI typically
patella
pain above.
patellofemoral
pain above.
patellofemoral
pain above.
not necessary,
but reveals
pathologic
changes in
articular
cartilage on
underside of
patella.
Patella stress
History may be
Anterior knee
Patella
Fracture may
fracture
unclear; pain likely
pain made
tenderness
not be apparent
insidious in onset.
worse by
activity,
(depends on
severity of
in plain
radiographs;
particularly
fracture).
MRI or CT may
Most common in active
people training in
ballistic sports.
Athletes who have
increased training
ballistic
movements
(jumping).
Normal knee
motion.
be required for
diagnosis.
volume and/or
intensity over past
weeks to months.
Medial knee pain
Degenerative
medial meniscal
tear
Develops over years
Symptoms
Medial joint
US may show
and presents in older
adults, usually without
often mild but
may complain
line
tenderness.
calcifications,
fraying of
inciting trauma.
of baseline
discomfort.
Knee motion
may not be
Pain with
pivoting or
smooth and
range may be
knee twisting.
limited.
Knee may
Provocative
catch or lock.
tests (eg,
peripheral
meniscus, and
cysts in regions
of swelling.
MRI generally
accurate and
diagnostic.
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Thesaly,
McMurray)
usually
positive.
Pain increases
with deep
squat.
Saphenous nerve
Pain may be
Pain increases
US may show
entrapment
caused by
typically
with palpation
or tapping
thickened nerve
or surrounding
benign stimuli
(Tinel sign) at
fluid.
or movement.
site of
Pain radiates
along course
entrapment.
Nerve block
relieves
symptoms.
of saphenous
nerve.
Pes anserine
Associated with
Anteromedial
Swelling at
US may reveal
bursitis
repeated valgus knee
strain (genu valgus).
knee pain in
area of pes
proximal
anteromedial
characteristic
changes of
anserine
tibia.
bursitis (eg,
tendon
insertion.
Area of bursa
tender.
Resisted knee
flexion or hip
fluid collection),
or pes anserine
tendinopathy.
adduction
elicits pain at
area of bursa.
Lateral knee pain
Iliotibial band
syndrome
Insidious onset of
Pain where
Tender ITB
Generally two
lateral knee pain
related to overuse.
ITB crosses
lateral femoral
where it
crosses lateral
patient types:
condyle.
femoral
Occurs primarily in
condyle.
runners, but also in
Pain increases
cyclists.
with
prolonged
Weak hip
abduction is
exercise but
common.
In runners, pain can
vary with pace &
increases on sloped
surfaces.
Novice or
female
runner with
weak hip
abduction
and internal
knee
may persist
rotation
afterwards.
(genu
valgum).
Pain increases over
time if activity
continues.
OR
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Advanced
runner with
reduced hip
adduction
and external
knee
rotation
(genu
varum).
Degenerative
Develops over years
Symptoms
Lateral joint
US may show
lateral meniscal
and presents in older
often mild but
line
calcifications,
tear
adults, typically
may complain
tenderness.
fraying of
without inciting
trauma.
of baseline
discomfort.
Knee motion
may not be
Pain with
smooth and
pivoting or
range may be
knee twisting.
limited.
Knee may
Provocative
catch or lock.
tests (eg,
peripheral
meniscus, and
cysts in regions
of swelling.
MRI generally
accurate and
diagnostic.
Thesaly,
McMurray)
usually
positive.
Pain increases
with deep
squat.
Posterior knee pain
Popliteal artery
Typically occurs in
Small
Pulsatile mass
US can identify
aneurysm
older individuals with
aneurysms
may be
aneurysm; can
cardiovascular risk
factors.
may be
asymptomatic.
palpable in
popliteal fossa.
compare with
contralateral
knee.
Claudication
symptoms
Associated with
with activity.
abdominal
aortic
aneurysm.
Popliteal artery
entrapment
Not associated with
Pain deep in
Resting
Rare cause of
risk factors for
cardiovascular disease.
calf or
popliteal
physical
examination
knee pain.
fossa.
unremarkable.
Claudication
More common
in young male
athletes.
symptoms
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y p
with vigorous
activities
involving
repeated
ankle dorsiand plantar
flexion.
Asymptomatic
at rest.
Popliteal (Baker's)
Damaged protruding
Posterior knee
Palpable
Often
cyst
posterior knee capsule
with many potential
pain and
tightness.
swollen cystic
structure in
associated with
intra-articular
popliteal fossa.
pathology or
causes.
knee
osteoarthritis.
If cyst ruptures,
knee pain &
tightness
typically resolve;
fluid may track
into calf causing
swelling.
US shows
compressible
fluid-filled mass,
typically medial
to vascular
bundle.
Popliteus
tendinopathy
Gradual onset of
Posterior knee
Tenderness at
US reveals
posterolateral knee
pain.
posterior
characteristic
aspect of
changes of
lateral femoral
condyle
tendinopathy.
pain.
Pain increases
Often caused by
excessive running
when runner
is "braking" or
(especially downhill) or
trying to
sprinting, also by
prevent
hiking downhill.
acceleration
while running
downhill.
(palpate
popliteal
tendon with
patient in
figure-of-4
position).
Resisted tibial
external
rotation may
elicit pain.
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US: ultrasound; VMO: vastus medialis oblique; MRI: magnetic resonance imaging; CT: computed
tomography.
Graphic 111562 Version 3.0
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Anterior knee joint line palpation and anatomy
The anterior joint line is readily palpated by placing your thumbs in
the recesses just inferolateral and inferomedial to the patella, as
demonstrated in the photograph.
Courtesy of Anthony Beutler, MD.
Graphic 89739 Version 2.0
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Key structures involved in patellar function
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Anatomy of the knee
Sagittal view of the knee anatomy demonstrating the relationship
between the bones, tendons, and bursae.
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Surface anatomy of anterior knee
Reproduced with permission from: Charlie Goldberg, MD. Image available at
meded.ucsd.edu/clinicalmed/.
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Medial patellar plica test
With the patient supine, the examiner first applies pressure with the thumb over
the inferior and medial apsect of the patellofemoral joint to interpose the medial
plica between the medial patellar facet and the medial condyle. While maintaining
this pressure, the knee is passively flexed from 0 to 90 degrees. Pain in extension
that is relieved at 90 degrees of flexion constitutes a positive test.
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Medial patella anatomy and stabilization
During extension of the knee, the femoral muscles (quadriceps femoris,
vastus medialis, and vastus lateralis) apply an oblique, laterally displacing
force to the patella (black arrow, top figure). The medial patellofemoral
ligament and the vastus medialis obliquus (lower figure) provide medial
stabilization of the patella against potential patellar subluxation or
dislocation.
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Patellar apprehension test
Patients with patellar dislocation and/or subluxation have pain in
the medial patellar retinacular area and are apprehensive when the
examiner tries to push the patella laterally.
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Knee menisci and related anatomy
(A) Superior view.
(B) Posterior view.
Reproduced with permission from: Lower limb. In: Clinically Oriented Anatomy, 7th ed, Moore KL, Dalley
AF, Agur AM (Eds), Lippincott Williams & Wilkins, Philadelphia 2013. Copyright © 2013 Lippincott
Williams & Wilkins. www.lww.com.
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Anterior anatomy of the knee joint
This drawing represents an anterior view of the knee with the patella removed
and demonstrates the relationship between the bones, menisci, and major
ligaments.
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Saphenous nerve
The saphenous nerve is the largest cutaneous branch of the femoral
nerve. It exits the adductor canal traveling deep to the sartorius muscle
emerging medially between the tendons of the sartorius and gracilis
muscles at the knee to become superficial. It travels distally adjacent the
great saphenous vein. The saphenous nerve provides sensory innervation
to the medial aspect of the leg.
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Location of pes anserine
The pes anserine is the insertion of the medial hamstring muscle tendons
and is located approximately 6 cm distal to the knee joint line along the
anteromedial tibial shaft.
Courtesy of Anthony Beutler, MD.
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Iliotibial tract anatomy
This lateral view of the thigh reveals the iliotibial band (or tract). The
gluteus medius lies deep to the gluteus maximus on the external
surface of the ilium.
Reproduced with permission from: Moore KL, Dalley AR. Clinically Oriented Anatomy,
5th ed, Lippincott Williams & Wilkins, Philadelphia 2006. Copyright © 2006
Lippincott Williams & Wilkins. www.lww.com.
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Neurovascular anatomy of the popliteal fossa
Distal femoral fractures and dislocations of the knee joint can cause injury to
nerves and blood vessels that travel through the popliteal fossa including the
popliteal artery and vein, tibial nerve, and common peroneal nerve.
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Popliteal artery aneurysm
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Asymptomatic popliteal (Baker's) cyst in a child
This photograph shows a posterior view of the knees of a healthy four-year-old boy with an asymptomatic
left popliteal cyst and no arthritis.
Copyright (©) 2020 American College of Rheumatology. Used with permission.
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Normal knee plain radiographs: AP, lateral, oblique,
and sunrise views
(A) Normal adult knee in the frontal AP projection.
(B) Normal adult knee seen in lateral projection. Lateral radiograph
of a normal adult knee. The positioning is nearly perfect, as judged
by the superimposition of the femoral condyles. The slight concavity
(small arrow) is the lateral (condylar) sulcus. The normal lucency of
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the suprapatellar recess (asterisk) identifies the deep surface of the
quadriceps tendon (arrow). The infrapatellar space (thick arrows) is
also normally lucent.
(C) Normal adult knee seen in externally oblique projection.
(D) Normal adult knee seen in internally rotated oblique projection.
(E) Axial ("sunrise") view of the normal patella. The lateral femoral
condyle (arrowheads) and the long lateral facet (dashed arrows) of
the patella are less steep than their medial counterparts.
AP: anteroposterior.
Reproduced with permission from: Chew NS, Robinson P, Harris JH Jr. Knee. In: Harris
& Harris' The Radiology of Emergency Medicine, 5th ed, Pope TL Jr, Harris JH Jr (Eds),
Lippincott Williams & Wilkins, Philadelphia 2013. Copyright © 2013 Lippincott
Williams & Wilkins.
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Contributor Disclosures
Carlton J Covey, MD No relevant financial relationship(s) with ineligible companies to disclose. Robert H
Shmerling, MD Consultant/Advisory Boards: Knowyourmeds [Advise on matters relating to the
Company’s business, technology and products]. All of the relevant financial relationships listed have been
mitigated. Karl B Fields, MD Consultant/Advisory Boards: Allard USA [Sports medicine]. All of the relevant
financial relationships listed have been mitigated. Jonathan Grayzel, MD, FAAEM No relevant financial
relationship(s) with ineligible companies to disclose.
Contributor disclosures are reviewed for conflicts of interest by the editorial group. When found, these are
addressed by vetting through a multi-level review process, and through requirements for references to be
provided to support the content. Appropriately referenced content is required of all authors and must
conform to UpToDate standards of evidence.
Conflict of interest policy
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