Additional Case 1

Additional Case 1Presentation to GPDavid, 21, apprentice plumberR leg injury during rugby game (last pm)Hit from R side during tackleImpact on upper outside 1/3 of leg (foot planted on ground)No previous Hx of knee injuriesNo PMH of noteReview the anatomy of the knee

CondyleCondyleCondyleEpicondyleArticulation Articulation Tubercle Tubercle

What is the functional role of the major ligaments of the knee?Patellar ligament: makes up the joint capsule on either side of the patella; maintains patella alignment Collateral ligaments: contribute to stability when standing (this is when they are taut) are also check ligaments for flexed rotation (permit but limit rotation)Oblique popliteal ligament: reinforces the joint capsule posteriorlyArcuate popliteal ligament: strengthens the joint capsule posterolaterallyAnterior cruciate ligament: limits posterior rolling of the femoral condyles on the tibial plateau during flexion; prevents posterior displacement of the femur on the tibia and hyperextension of the knee jointPosterior cruciate ligament: limits anterior rolling of the femur on the tibial plateau during extension; also prevents anterior displacement of the femur on the tibia and helps prevent hyperflexion of the knee joint.Based upon the mechanism described, which structure/s are likely to be injured?ACLMedial collateral ligament tearWhat are the typical mechanisms which lead to injury to the major ligaments and menisci?ACL:Non-contact change of direction; hyperextension on landing from a jump or; direct valgus forcePCL:Contact injury to the ground or; clash of kneesMCL:Contact valgus injuryMeniscal tears:Twisting on a planted footExaminationPositive swipe testTenderness along the subcutaneous border of the fibula (around the area he identifies as the impact site)Grade 3 laxity with valgus stressLachmans Test and anterior draw are inhibited by pain from DavidInitial managementTell David he has injured a major knee ligament and that the pain is from local bruisingKnee splint + crutchesRefer for physiotherapy rehab and advice on weight bearing/return to work+sportReview the knee examination and the pathology which each special test is aimed at demonstratingLook:Swelling, wasting, spasm, scars, erythema, deformitiesPosture (leg length, foot posture)Gait (walk 10 steps, in/out of chair, socks on/off)Feel:Skin: temperatureQuadriceps bulk (loss of tone/bulk, spasm, tenderness, loss of continuity in extension)patella (tenderness, thickened ligament, gaps, creptius, articular surface, suprapatellar bursa, prepatellar bursa)Medial/lateral femoral condyles and epicondylesMedial and lateral colateral ligamentsMedial and lateral joint linesPopliteal fossa (masses, pulse)Knee effusion: is the swelling within joint or extrinsic to joint?Patella tap: slide hand down thigh towards knee; push down gently on patellaSwipe/bulge test: stroke medial side upwards; empty suprapatellar pouch; stroke lateral side downwardsMove:Flexion: 135; extension: 0-10Observe patellar trackingSpecial testsPatella apprehension: patella dislocation (knee flexed 30; thumbs on medial border; lateral force)MCL/LCL stress test: MCL/LCL tear (knee flexed 15-30; varus/valgus force to distal tibia; repeat in full extension)Anterior draw test: ACL tear (knee flexed; sit on foot; gently pull upper tibia forwards)Lachmans test: ACL tear (knee slightly flexed; stabilise femur with hand; apply pressure to posterior proximal tibia to move it anteriorly)McMurrays test: medial/lateral meniscal tear (full flexion; externally rotate foot + varus force Vs internally rotate foot + valgus force; extend kneeWhat is the effect of muscle inhibition and spasm on ligament testing ?Source: Angus HannWith Ligament testing you assess symptom response ( pain), laxity and end feel. Acute spasm will guard the joint and give u a false negative on Ligament testing.Inhibition affects strength. May be unable to straight leg raise. Pain causes reflexive inhibition and may cause knee to give way. Need to encourage patient to relax when testing. Acute knee difficult. 3. What could be done to improve your confidence in the Lachman's and anterior draw test in this case? Tell the patient to relax and practice more UptoDate: The stability of the knee is assessed by varus and valgus stress testing, the Lachman's test, and the anterior and posterior drawer signs. The usefulness of these tests is limited if the patient's muscles are not relaxed, as quadriceps contraction masks signs of instabilityTo improve confidence be Angus or Pete

4. What happens to the quadriceps muscle group with knee injury and splinting, does it matter? - what proactive measures may limit or prevent this?

Rupture patella loses its anchor patella moves inferiorly (towards foot) unable to straighten knee A large sudden load may cause the entire insertion to be compromised, leading to complete rupture. Repetitive loading, particularly eccentric loads, causes microfailure, usually at the muscle tendon junction. This microfailure can result in partial tearsStrain due to repetitive functional overload, knees subjected to high levels of repeated loading of extensor mechanism Trigger 3

The following week you are surprised to see David represent with a letter from the physio agreeing with your diagnosis about the knee injury, but expressing concern about the cause of the ongoing leg pain. Repeat clinical examination shows a large effusion and there is laxity with Lachman's test. You refer David for an x-ray which is shown below. Describe the anatomy seen on the x-ray image.

FibulaHead Neck Body Femortibial joint space

Describe any visible pathology on the x-ray image. hyper-extension lateral view allows assessment of slope of intercondylar roof in relation to the tibial plateau;Plain radiographs cannot be used to diagnose ACL tears. In some cases, an avulsion fracture of the anterolateral tibial plateau (ie, Segond fracture) is identified at the site of attachment of the lateral capsular ligament.

3. Review the mechanism of injury and describe the sequence of events that occurred to his knee.The impact was on the upper outside one third of the leg while his foot was planted on the ground.runninglanding from a jump

1. What is the common mechanism for ACL rupture?A blow to the side of the knee, which can occur during a football tackle, may result in an ACL tear.Coming to a quick stop, combined with a direction change while running, pivoting, landing from a jump, or overextending the knee joint (called hyperextended knee), also can cause injury to the ACL.Basketball, football, soccer, and skiing are common causes of ACL tears

2. ACL ruptures in children are uncommon - why? - What injury might a child sustain instead?The ACL infrequently ruptures in children. Rather the bone on either end comes off.3. What are the indications for imaging knee injuries?

4. What are the potential long term sequelae to an ACL rupture which is not operated on in this age group?Depends on activity level of patientLong term sequelae include instability, particularly with pivoting type sports, but even walkingInstability causes damage to the menisci and the other ligaments