Presentation on theme: "The Knee. Anatomy- 1 st layer The knee joint Made up of two joints: Tibiofemoral joint: Hinge joint Collateral ligaments Cruciate ligaments Menisci Patellofemoral."— Presentation transcript:
Anatomy- 1 st layer
The knee joint Made up of two joints: Tibiofemoral joint: Hinge joint Collateral ligaments Cruciate ligaments Menisci Patellofemoral joint: Medial retinaculum Patellar tendon
Movements of the knee Flexion Extension Accessory movements in certain positions can take place with external forces: Valgus Varus External rotation Internal rotation
Patient walks in c/o knee pain What is the mechanism of injury? A planted foot with a valgus force and/ or twisting movement is a serious position of danger for the knee Was there a noise? Did the knee swell up immediately? Is there any bruising? Was the patient able to play on? Is the patient able to weightbear? Is there any clicking/ giving way/ locking now?
Patient walks in c/o knee pain Acute, chronic or sub-acute? Does pain increase or decrease with activity? Patient’s job and leisure activities and any possible contributing factors? Gait? Limping or normal walking? Able to cope with stairs? Does the patient have any hip pain? Any back pain? Leg pain? Could this be an L3 Nerve root compression?
Where is the pain?
Causes of haemarthrosis ACL tear PCL tear Patella dislocation Osteochondral fracture Peripheral tear of the meniscus (more commonly medial) Hoffa’s syndrome (acute fat pad impingement)
More clinical pearls There is little effusion with collateral ligament tears An effusion that develops after a few hours or the next day is a feature of meniscal and chondral injuries Assume everything with a pop or a snap is an ACL tear Assume all clicking and locking is meniscal... Especially loss of extension If the knee locks in extension and flexion is difficult it is likely to be patellofemoral pain Giving way can be indicative of ACL or meniscal injury, but if this is longstanding with no injury, it may be muscle weakness
Ottawa Knee rules Age 55> or <18 Tenderness at head of fibula Isolated patella tenderness Inability to flex to 90° Inability to bear weight both immediately and in the emergency department (4 steps) High suspicion are: High speed injuries Children or adolescents Clinical suspicion of loose bodies 90% of knee X-rays are normal.
Assessment Observe active range: ability to squat if appropriate, control through the knee. Observe position of patella in standing Passive range of movement in supine: loss of particularly extension will cause long term problems Palpate the patella for differences from side to side
ACL assessment Anterior Drawer test: Knee at 90° flexion, foot kept stable Tibia drawn anteriorly Assess for degree of movement and end point Lachman’s Test Knee at 15° flexion Draw tibia forward Assess for degree of movement and end point
ACL assessment Pivot Shift Test: Tibia internally rotated Knee in full extension Apply a valgus force In a knee with ACL deficiency the condyles will sublux. The knee is then flexed, looking for the clunk of a reduction, a positive Pivot shift. Extending the knee again, if the knee clicks, this is a positive ‘jerk test’. Loss of ROM, especially extension Lateral joint line tenderness due to lateral joint capsule stretching due to subluxation Medial joint line tenderness if associated meniscal injury
ACL injury Relatively common in sport Over ACL reconstructions performed in the USA every year Generally sports that involve pivoting... Football, netball, rugby, gymnastics, downhill skiing etc x higher risk in females Can occur in isolation or with meniscal, articular cartilage and MCL injury
ACL injury 75% rupture chance if there was a twist, a pop and a click! Extremely painful, particularly at first Athletes are initially unable to continue their activity, and further activity is limited by significant haemarthrosis. Very occasionally this can be delayed. Some athletes ‘try’ to play again when knee has settled and report incidences of acute instability Examination of the knee when swollen is very difficult. Diagnosis should be based on subjective report, and appropriate referral made. MRI is the imaging of choice, but X-ray is needed to check for an avulsion fracture (‘Segond’). 80% of ACL tears have a bone bruise over the lateral femoral condyle.
PCL assessment Posterior sag: Both knees flexed to 90° and patient relaxed Observe tibia position relative to femur Reverse Lachman’s Test Lachman’s prone! Posterior drawer test Knee at 90°, push tibia posteriorly Also assess in internal and external rotation Assess range and quality of end point X-ray to ensure no bony avulsion MRI is the gold standard for PCL tear assessment
PCL injury PCL is a primary restraint to posterior drawer and secondary restraint to external rotation. Less common than ACL (thicker ligament), usually associated with meniscal and chondral injury as well as lateral meniscus injury. Usually results from a blow to the anterior tibia with the knee flexed. Hyperextension may also result in injury to the PCL and posterior capsule. Pain is poorly defined, posterior pain, sometimes in the calf.
Collaterals MCL: Valgus force LCL: Varus force Test at full extension and also 30° flexion Grade 1: hurts on testing with no laxity visible Grade 2: hurts and gaps with laxity but with end point Grade 3 isn’t that painful on testing, LARGE amount of movement. Feels ‘wobbly’. Frequently associated with ACL injuries, often capsular tearing with this grade, swelling therefore present Always local tenderness at insertion point
Collateral ligament injury MCL is a result of a valgus force LCL tear is less common and due to a high-energy direct varus stress on the knee and often associated with PCL tear Treatment is generally conservative, although bracing is required for more severe injuries.
Menisci Pain on palpation of the joint line Positive McMurray’s test: The knee is flexed and at various stages of flexion the tibia is internally and externally rotated Pain and a ‘clunk’ make this test positive Joint effusion Pain on squatting (especially if posterior horn is involved) Restricted ROM MRI is investigation of choice
Meniscal injury Generally a twisting injury Doesn’t have to be a quick injury Degree of pain associated with an acute injury can vary dramatically. Sometimes a tearing sensation will be felt Sometimes pain is of late onset... Up to 24 hours later Small tears may also occur with minimal trauma in the older athlete as a result of degenerative changes Surgical indications include: Inability to continue playing Locked knee or severe lack of ROM, particularly EOR flexion Palpable clunk on McMurray’s Test Associated ACL tear No change after 3 weeks post-injury
Patella and tendon Assess the patella in 30° knee flexion, push the patella laterally, if the patient has apprehension, consider a dislocating patella Pain infrapatella is usually the tendon (or can be bursal) Fractured patella can occur due to direct trauma or through quadriceps avulsion. In adolescents consider Osgood Schlatter’s Disease, particularly if a prominent tibial tubercle. This is a growth plate osteochondritis
Articular cartilage damage Chondral damage can be a major cause of symptoms in the knee Can be primary or secondary (ligamentous instability... ACL has high incidence of medial & lateral femoral condyle and tibial plateau chondral damage)
Anterior knee pain 20-40% of all MSK consultations in general practice Generally AKP is due to: Patellofemoral pain Patella tendinopathy Other causes can include: Synovial plica Pre-patella/ infrapatella bursitis Fat pad impingement Quadriceps tendinopathy Patellofemoral instability
Patellofemoral pain Generally insidious onset, vague pain Often secondary to an acute incidence A diffuse ache exacerbated by loading eg stairs or running... Doesnt tend to have to be eccentric loading only. Prolonged sitting can be painful Worsening pain while exercising tends to be PFPS, while pain at start of exercise, and ceasing of exercise tends to be Patella tendinopathy Previous injury to the knee predisposes one to PFPS Any effusion around the knee >15ml of fluid will switch off VMO (major stabiliser of the knee) increasing the risk of adverse knee mechanics and therefore PFPS Assess the patella position relative to the painfree side
Patella tendinopathy Mostly involves jumping/ multidirectional sports Significantly more painful with eccentric loading rather than any other type of loading Pain is inferior pole of the patella, or the tendon Pain is always bad in the morning Chronic tendinopathy can take 3-6 months to settle Surgery is only indicated after a considered and lengthy conservative programme has failed
Lateral knee pain Mostly due to Ilitobial band friction syndrome (ITBFS) Repeated flexion/ extension at the knee causes ITB to rub on the lateral epicondyle Training errors and biomechanical problems are the major causes of ITBFS Occasionally biceps femoris tendon can become inflamed and tender Superior tib-fib joint can also give lateral knee pain OA of the lateral compartment Nerve root irritation/ entrapment
Medial knee pain PFPS Medial meniscal injury OA of the medial compartment Pes anserinus bursitis Referred pain
Posterior knee pain Biceps femoris, gastrocnemius or popliteus tendinopathy Referred pain Baker’s cyst Posterolateral corner injury DVT Claudication
Advice to you as GPs If it’s swollen, refer to orthopaedics If it’s anterior knee pain, always refer to physio If it’s giving way, refer to orthopaedics A painless click is not a problem, as long as no locking or giving way is associated. Kids with Osgood’s should rest when sore, and try to get strong when condition is stable Rest will NEVER fix an injury. Cycling (not standing on the pedals) is generally a knee friendly sport. Running is not.