9Movements of the knee Flexion Extension Accessory movements in certain positions can take place with external forces:ValgusVarusExternal rotationInternal rotation
10Patient 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 kneeWas 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?
11Patient 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?
13Causes of haemarthrosis ACL tearPCL tearPatella dislocationOsteochondral fracturePeripheral tear of the meniscus (more commonly medial)Hoffa’s syndrome (acute fat pad impingement)
14More clinical pearlsThere is little effusion with collateral ligament tearsAn effusion that develops after a few hours or the next day is a feature of meniscal and chondral injuriesAssume everything with a pop or a snap is an ACL tearAssume all clicking and locking is meniscal... Especially loss of extensionIf the knee locks in extension and flexion is difficult it is likely to be patellofemoral painGiving way can be indicative of ACL or meniscal injury, but if this is longstanding with no injury, it may be muscle weakness
15Ottawa Knee rules Age 55> or <18 Tenderness at head of fibula Isolated patella tendernessInability to flex to 90°Inability to bear weight both immediately and in the emergency department (4 steps)High suspicion are:High speed injuriesChildren or adolescentsClinical suspicion of loose bodies90% of knee X-rays are normal.
16AssessmentObserve active range: ability to squat if appropriate, control through the knee.Observe position of patella in standingPassive range of movement in supine: loss of particularly extension will cause long term problemsPalpate the patella for differences from side to side
17ACL assessment Anterior Drawer test: Lachman’s Test Knee at 90° flexion, foot kept stableTibia drawn anteriorlyAssess for degree of movement and end pointLachman’s TestKnee at 15° flexionDraw tibia forward
18ACL assessment Pivot Shift Test: Loss of ROM, especially extension Tibia internally rotatedKnee in full extensionApply a valgus forceIn 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 extensionLateral joint line tenderness due to lateral joint capsule stretching due to subluxationMedial joint line tenderness if associated meniscal injury
19ACL injury Relatively common in sport Over ACL reconstructions performed in the USA every yearGenerally sports that involve pivoting... Football, netball, rugby, gymnastics, downhill skiing etc.2-10 x higher risk in femalesCan occur in isolation or with meniscal, articular cartilage and MCL injury
20ACL injury 75% rupture chance if there was a twist, a pop and a click! Extremely painful, particularly at firstAthletes 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 instabilityExamination 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.
21PCL assessment Posterior sag: Reverse Lachman’s Test Both knees flexed to 90° and patient relaxedObserve tibia position relative to femurReverse Lachman’s TestLachman’s prone!Posterior drawer testKnee at 90°, push tibia posteriorlyAlso assess in internal and external rotationAssess range and quality of end pointX-ray to ensure no bony avulsionMRI is the gold standard for PCL tear assessment
22PCL injuryPCL 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.
23Collaterals MCL: Valgus force LCL: Varus force Test at full extension and also 30° flexionGrade 1: hurts on testing with no laxity visibleGrade 2: hurts and gaps with laxity but with end pointGrade 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 presentAlways local tenderness at insertion point
24Collateral ligament injury MCL is a result of a valgus forceLCL tear is less common and due to a high-energy direct varus stress on the knee and often associated with PCL tearTreatment is generally conservative, although bracing is required for more severe injuries.
25Menisci 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 rotatedPain and a ‘clunk’ make this test positiveJoint effusionPain on squatting (especially if posterior horn is involved)Restricted ROMMRI is investigation of choice
26Meniscal injury Generally a twisting injury Doesn’t have to be a quick injuryDegree of pain associated with an acute injury can vary dramatically.Sometimes a tearing sensation will be feltSometimes pain is of late onset... Up to 24 hours laterSmall tears may also occur with minimal trauma in the older athlete as a result of degenerative changesSurgical indications include:Inability to continue playingLocked knee or severe lack of ROM, particularly EOR flexionPalpable clunk on McMurray’s TestAssociated ACL tearNo change after 3 weeks post-injury
27Patella and tendonAssess the patella in 30° knee flexion, push the patella laterally, if the patient has apprehension, consider a dislocating patellaPain 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
28Articular cartilage damage Chondral damage can be a major cause of symptoms in the kneeCan be primary or secondary (ligamentous instability... ACL has high incidence of medial & lateral femoral condyle and tibial plateau chondral damage)
29Anterior knee pain 20-40% of all MSK consultations in general practice Generally AKP is due to:Patellofemoral painPatella tendinopathyOther causes can include:Synovial plicaPre-patella/ infrapatella bursitisFat pad impingementQuadriceps tendinopathyPatellofemoral instability
30Patellofemoral pain Generally insidious onset, vague pain Often secondary to an acute incidenceA diffuse ache exacerbated by loading eg stairs or running... Doesnt tend to have to be eccentric loading only.Prolonged sitting can be painfulWorsening pain while exercising tends to be PFPS, while pain at start of exercise, and ceasing of exercise tends to be Patella tendinopathyPrevious injury to the knee predisposes one to PFPSAny 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 PFPSAssess the patella position relative to the painfree side
31Patella tendinopathy Mostly involves jumping/ multidirectional sports Significantly more painful with eccentric loading rather than any other type of loadingPain is inferior pole of the patella, or the tendonPain is always bad in the morningChronic tendinopathy can take 3-6 months to settleSurgery is only indicated after a considered and lengthy conservative programme has failed
32Lateral knee painMostly due to Ilitobial band friction syndrome (ITBFS)Repeated flexion/ extension at the knee causes ITB to rub on the lateral epicondyleTraining errors and biomechanical problems are the major causes of ITBFSOccasionally biceps femoris tendon can become inflamed and tenderSuperior tib-fib joint can also give lateral knee painOA of the lateral compartmentNerve root irritation/ entrapment
33Medial knee pain PFPS Medial meniscal injury OA of the medial compartmentPes anserinus bursitisReferred pain
35Advice to you as GPs If it’s swollen, refer to orthopaedics If it’s anterior knee pain, always refer to physioIf it’s giving way, refer to orthopaedicsA 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 stableRest will NEVER fix an injury.Cycling (not standing on the pedals) is generally a knee friendly sport. Running is not.