Knee Pain

Anatomie du genou

The knee is a joint often concerned with rheumatological diseases extremely numerous. The diagnosis is facilitated by the synovial puncture, to be systematic when a effusion is detected.



He specifies :

– The installation mode of pain: sudden or gradual, possibly after trauma;

– The topography of pain: anterior, posterior, internal or external side, global;

– The schedule of pain: mechanical or inflammatory;

– Possible triggers: walking on rough ground, up or down stairs;

– The intensity of pain, progressive profile and sensitivity to treatment;

– The functional impact: reduction in the walking, limping, using a cane, although parameters evaluated by Lequesne algofunctional index for gonopathies;

– Symptoms of potential support: crunches, blocking phenomena of dérobement, swelling;

– History, general signs, symptoms remotely, etc.

Physical examination:

The clinical examination is always bilateral and comparison.

The patient standing there looking a static disorder of one or both lower limbs varus or valgus (deviation leg in or out), genu flexion or hyperextension.

At the walk, we will search for any lameness.

Lying on the patient, a search:

– Synovial effusion (patellar shock), with a possible popliteal cyst;

– Suffering from patellofemoral compartment: pain on percussion patellar pain on palpation of internal and external facets of the patella (dislocation after inside and outside), a sign of the plane;

– Suffering a meniscal (internal or external):

– Pain to the pressure of the line spacing,

– Pain triggered by the pressure of the leg bent at 90 ° on a patient in the prone position, with rotation maneuvers foot(grinding test Appley)

– Pain m anoeuvre Mac Murray: triggering a sharp pain to the progressive extension layout knee with simultaneous pressure on the line spacing and forced rotation of the knee,

– Pain in the knee hyperextension;

– A reduction of the passive mobility of the amplitudes, the normal values are: 5 to 10 ° in extension, 150 ° flexion;

– Suffering knee ligament stabilizers elements:

– Abnormal lateral movements valgus and varus forced, reflecting achievement of lateral ligaments and condylar shells

– M ouvements of anterior drawer or later, to search the knee flexed to 60 °, indicating a lesion of the anterior cruciate ligament or posterior

– Lachman test,

– Looking for a jump in the jerk test and Lemaire test;

– A quadriceps wasting;

– Do not forget the systematic examination of the hip in case of isolated knee pain (referred pain).

Imaging tests:

Standard radiology:

It must involve at least six following impacts:

– Two supports opposite knee;

– Profile two knee flexion 30 °;

– Axial impacts (or patellofemoral) at 30 ° and 90 ° of flexion.

We often associate their impact “schuss” (both knees face up at 30 ° flexion), more sensitive than the standard incidence of side search for a tibiofemoral joint space.

Finally, goniometry, for the study of the axes can be justified before any surgery.

Other imaging tests:

They especially warranted in etiologic a gonopathie no radiological translation. Various tests can be interesting: bone scan, opaque arthrography, possibly supplemented with a scanner (arthrography), especially MRI.

Other tests:

The usual biology is particularly interesting for looking for inflammation.

The suspicion of effusion imposes a synovial puncture. This is an easy gesture, the needle being inserted under the upper outer corner of the ball, the other hand pressing the inner part of the ball to make the “yawn”. This gesture implies particularly strict aseptic conditions. Should be evaluated:

– The macroscopic appearance of synovial fluid: color, transparency, viscosity;

– Its rich elements (count) and type (neutrophils, lymphocytes, etc.);

– The possible presence of microcrystals (polarized light);

– The possible presence of germs (direct examination and culture).

The synovial biopsy (needle, surgical or per-arthroscopic) has an interest almost exclusively diagnosed in cases of suspected tuberculosis (histology and culture).

Arthroscopy is interesting not so much now for diagnostic, due to improved imaging techniques, especially as therapeutic (meniscal pathology).

Differential diagnosis :

It should eliminate various pathologies that can be the cause of knee pain, although not related to a breach of the joint itself:

– Cruralgia (abolition of the patellar reflex, sign Leri, etc.);

– Hip disease: systematic review of the ipsilateral hip and pelvis radiograph in doubt;

– A juxtaarticular bone disease, femoral or tibial: primary tumors, benign or malignant, osteomyelitis, stress fracture;

– Especially a pathology abarticular tendinoligamentaire:

– Tendinobursite of crow’s feet to the surface of the tibia,

– Tendinitis quadriceps above the patella,

– Sub-patellar tendinitis,

– Hygroma prérotulien, especially post-traumatic, sometimes septic or microcrystalline

– Popliteal cyst, always satellite arthropathy of the knee.


In practice, the etiological based on the following discussion points:

– Is the post-traumatic arthropathy?

– If it is not, is it mechanical or inflammatory arthropathy?

– In all cases the standard radiology it is normal or not?

Post-traumatic knee pain:

Different etiologies should be mentioned, depending on the speed of onset of pain after the injury and any accompanying signs.

In all cases, the standard radiology is not contributory except by its normality.

Knee sprain:

The knee sprain can be mild (pain on a ligament trip, usually the internal lateral ligament without instability) or severe, with effusion (or haemarthrosis), with derobements instability and abnormal lateral movements (lateral ligaments) and / or drawer (cruciate ligaments). The precise lesion diagnosis is then based on arthrography or MRI, radiology standard being normal.

Post-traumatic meniscus rupture:

It almost always concerns the medial meniscus, especially the posterior horn, and affects young athletes. It should be considered in the occurrence of recurrent blockages phenomena followed by effusion. Diagnosis, talked about the positivity of meniscal maneuvers, is confirmed by arthrography or MRI. Arthroscopy has in this context a particular therapeutic interest.


She succeeds trauma, inconstant, variable in a matter of days to weeks. The clinical picture may be inflammatory pace, but VS is normal and effusion, frequent, mechanical formula. The standard radiology is long normal or may reveal epiphyseal demineralization, typically speckled or mottled. The diagnosis is made by bone scintigraphy (intense regional uptake but not specific) and especially MRI.

Hemarthrosis posttraumatic:

Reveals topography of lesions and severity vary, it is diagnosed by the puncture. The lack of recent trauma calls before a hemarthrosis, seek another cause: villonodular synovitis, synovial tumor, benign (hemangioma synovial synovialome) or malignant (synovial sarcoma), bleeding disorder (hemophilia, anticoagulation), chondrocalcinosis, advanced knee OA.

Gonalgia non traumatic:

Arthropathy mechanical speed:


It is by far the main cause. As with any location osteoarthritis, we must remember the absence of radiological parallelism, with the possibility of very disabling inaugural flare-ups (synovial fluid mechanics), in contrast with standard strictly normal clichés. Here we must stress the importance of the impact “schuss” and especially of arthrography and MRI, which may highlight localized cartilage lesions. The chondroscopie is more accurate but rarely used in clinical practice as too invasive.

* Treatment of knee osteoarthritis:

Medical treatment:

The medical management of knee OA differs with the changing profile of the disease, but is in all cases to avoid or delay surgery, the details and the results are less obvious than for the hip. Again, the absence of radio-clinical parallelism is obvious, therapeutic indications depending on the clinical symptoms and not the iconography:

– The lifestyle and dietary recommendations are identical to those recommended for osteoarthritis, with particular emphasis on the importance of losing weight (one kg of body weight is multiplied by three on each knee!).

The up and down stairs should be reduced, as well as carrying heavy loads and walk on rough ground.

– Drug treatments are always recommended: analgesics, NSAIDs and Aasal. In general, NSAIDs should not be prescribed continuously but in short courses of a few days (in association with gastric protection beyond 65 years and / or in case of ulcer history).

– Intra-articular injections of cortisone derivatives found a place in the advanced osteoarthritis congestive after evacuation of synovial effusion.

– Intra-articular injections of hyaluronic acid (usually three injections one week apart) are available in case of knee osteoarthritis with little or no effusion, inadequately relieved by other treatment, with crippling daily pain, in active patients. It will be shown all (and effective) as radiological involvement is moderate.

Symptomatic improvement is often delayed by several weeks and lasts several months (18 months on average).

– Rehabilitation aims to maintain range of motion and muscle trophicity.

Business in the absence of effusion, it must be gentle, always progressive and infra-painful.

It must be completed, if possible, a self-rehabilitation at home. Using tailored orthotics may be recommended (fight against a varus morphotype or valgisant).

– The crenotherapy has its followers …

Surgical treatment:

It comprises two approaches: the realignment surgery and prosthetic surgery:

The realignment surgery is for internal or external femorotibial gonarthroses complicating a static disorder of the knee (respectively varus and valgus knee), although specified by pangonométrique balance sheet. If internal tibiofemoral osteoarthritis genu

varum, may be offered a tibial valgus osteotomy. The femoral varus osteotomy is rarely indicated (external tibiofemoral osteoarthritis of valgus).

– The prosthetic surgery offers uni or bi-compartimentaires prostheses (which are total knee), unconstrained or semi-constrained by the state of the capsular ligament apparatus.

Condylar osteonecrosis:

Mostly internal, it results in a lateralized pain, sometimes brutal and debilitating occurrence. It complicates more likely a medial knee osteoarthritis, or at least an excessive pressure on the internal compartment Genu Varum. The standard radiology can be normal or belatedly reveal a flattening and a condensation of the condyle or a receiver. Early, bone scintigraphy (uptake intense and localized) and MRI examinations of choice.


It concerns mainly the young boy and preferentially affects the femoral condyle inside, resulting in blockages sometimes supplemented recurrent knee pain. Radiographic findings and MRI are identical to those of osteonecrosis.

Patellofemoral pathologies:

The recurrent dislocation of the patella concerns electively the girl with sudden knee pain and feelings of “dislocation” in the march, causing falls. The shots in axial impacts reveal a fémororotulienne dysplasia appearance with lateral subluxation of the patella.

The patellar chondromalacia corresponds to a focused cartilage defect of a facet patellar sometimes traumatic or complicating patellofemoral dysplasia. It is the cause of mechanical knee pain in young patients and its diagnosis based on MRI and especially arthroscopy (cartilage focal ulcerations).

The patellofemoral osteoarthritis, long tolerated, may complicate the course of the previous pathologies.

Tear of meniscus:

It corresponds to a meniscal degenerative disease, usually on the medial meniscus and willingly associated with internal tibiofemoral osteoarthritis. Diagnosis is made by arthrography, MRI, or arthroscopy.

More rare causes of mechanical gonopathies:

Primitive chondromatose manifested by complicated locking episodes of effusion.

The diagnosis in the absence of calcifications foreign bodies (osteochondroma), based on arthrography (± scanner) and arthroscopy, also made therapeutic (synovectomy).

Synovitis villonodular is manifested by recurrent effusions hemarthrosic happy guy.

The standard radiology being normal, the diagnosis is mainly based on arthroscopy, which allows histological confirmation (benign synovial tumor pigmented).

The other synovial tumors, benign or malignant, are exceptional. Their diagnosis is histological.

Plica synovium synovial withdrawal from occasionally come between the kneecap and the trochlea, causing pseudoméniscal blocking phenomena. Diagnosis is made on arthrography and especially arthroscopy, which also processes (section).

Tabes arthropathy characterized by classically painless joint destruction, has become exceptional.

Inflammatory arthropathy of pace:

It is then of arthritis, which can be limited to the knee or incorporated into an oligo- or polyarticular pathology. In practice, it essentially meets three clinical situations.

Acute monoarthritis of the knee:

* Septic arthritis pyogenic:

Monoarthritis is so shrill, integrating in a septicemic context, with evidence of the causative agent (primarily Staphylococcus aureus) in synovial fluid, readily puriform but also in blood cultures or at the door when it is found.Regarding gonococcal monoarthritis, we must emphasize the fragility of the germ, requiring sampling precautions and highly specific isolation.

* Microcrystalline Arthritis:

Gout can start with an inaugural monarthritis a knee. The diagnosis is then based on the context (man fifties) and the detection of uric acid crystals in the synovial fluid. For the record, uric acid may be normal during or immediately after an acute gouty access and rise secondarily.

The location of knee chondrocalcinosis is commonplace, causing acute monoarthritis “pseudogoutteuse”. Again, diagnosis based on the detection of calcium pyrophosphate microcrystals in synovial fluid, but also the discovery of calcifications: meniscus and cartilage in the knee, but also symphysis pubis and triangular fibrocartilage.

* Acute Monoarthritis other origin:

Chronic inflammatory rheumatism exceptionally start with an inaugural acute monoarthritis.

Subacute or chronic monoarthritis:

Subacute or chronic monoarthritis of the knee can rarely inaugurate a chronic rheumatic disease (rheumatoid arthritis, spondyloarthritis, psoriatic arthritis), a reactive arthritis, or systemic disease (CTD, sarcoidosis, periodic disease, etc.).However, these conditions may include, in their evolution, a violation of the knees.

In chronic monoarthritis with no obvious etiology knee synovial biopsy is imperative to formally rule out TB (culture, histology).

Background oligo or polyarthritis:

All diagnoses are possible.

* Infectious Etiology:

The oligoarthritis banal germs are exceptional and must rather discuss other bacterial agents: brucellosis, Lyme disease or syphilis. Viral oligoarthritis are frequent, rubella virus, parvovirus B19, hepatitis B virus, HIV, HTLV-1 (Human T-lymphotropic virus), etc.

Reactive arthritis, which must reconcile rheumatic fever and post-streptococcal rheumatism, usually begin with an asymmetric oligoarthritis of the lower limbs.

* Etiologies microcrystalline:

Gout can sometimes be expressed in a oligoarticular form, rarely inaugural.

* Inflammatory etiologies:

All chronic rheumatic diseases and systemic diseases with articular tropism (lupus, scleroderma, vasculitis, Behcet’s disease, Sjogren’s syndrome, sarcoidosis, periodic disease, etc.).