Orthopaedic knee conditions Flashcards
What are the different key ligaments of the knee?
Cruciate ligaments – ACL, PCL. Collateral ligaments: MCL, LCL.
Describe menisci and their function
Specialised C-shaped cartilages – triangular in cross-section, medial – attached to deep MCL, lateral. Function – aid force transmission, increase stability.
What are the causes of meniscal tear? (acute + degenerative)
Acute – twisting especially in deep flexion. Degenerative – OA.
Medial meniscal tears more common – more fixed structure.
Describe the symptoms of a meniscal tear
Pain, Clicking, Locking, Intermittent swelling.
Describe the examination of a meniscal tear
LOOK – effusion. FEEL – tender joint line at point of tear. MOVE – mechanical block to movement, fail deep squat, McMurrays test positive, Thessaly’s test positive.
What investigations would you carry out for a meniscal tear?
X-ray – arthritis, fracture. MRI – most sensitive test
How do you treat a meniscal tear?
Unlikely to heal if poor blood supply.
Non-operative: rest, NSAIDs, physiotherapy – hamstring and quadriceps strengthening.
Operative: Arthroscopy – repair, resection.
How do you treat knee OA?
Weight loss, analgesia, activity modification, braces, walking aids, visco-supplementation, steroid injection.
Total knee replacement – cruciate retaining or cruciate sacrificing.
What is the function of the ACL?
Primary restraint to anterior translation of the tibia relative to femur, secondary restraint to tibial rotation and Varus/valgus stress.
What kind of injury is an ACL tear?
Non-contact pivot injury. Sudden stop or changes in direction, jumping and landing e.g. football, rugby etc. Affects females more - difference in landing biomechanics neuromuscular activation patterns.
Describe the presentation of an ACL tear
Heard a ‘pop’ or ‘crack’.
Immediate swelling (70%): haemarthrosis (bleeding into joint).
Unable to continue playing – can walk in straight line.
Deep pain.
Describe the examination of an ACL tear
LOOK – effusion (if recent injury). FEEL. MOVE – anterior draw, Lachman’s test, Pivot shift – best done under anaesthetic.
Describe the investigation of an ACL tear
X-ray: Segond fracture – avulsion (pulling/tearing away) # of anterolateral ligament. MRI – ACL, Meniscii (lateral tear – simultaneous with ACL tear (48%); medial – secondary to shear from chronic instability), MCL.
How would you treat an ACL tear?
Non-operative: focussed quadriceps programme. Operative: ACL reconstruction – +/- partial meniscectomy +/- ligament repair or augmentation; hamstring graft.
What is the function of superficial and deep MCL?
Superficial – primary restraint to valgus stress.
Deep – contributes to full knee extension, attaches to medial meniscus, continuous with joint capsule.
What kind of injury is MCL tear?
Most common ligament injury of the knee. Severe valgus stress – usually contact-related, associated injuries – ACL tear, meniscal tear.
Describe the presentation of an MCL tear
Heard a ‘pop’ or ‘crack’. Pain++ (medial side) Unable to continue playing. Bruising medial knee. Localised swelling.
Describe the examination of an MCL tear
LOOK – medial swelling, bruising. FEEL – tender medial joint line, tender femoral insertion of MCL. MOVE – painful in full extension, opening on valgus stress.
How do you investigate an MCL tear?
X-ray – may be normal, calcification at femoral insertion (Pelligrini-Stieda) – chronic injury. MRI – modality of choice, assess location and severity of injury, identify other pathologies.
What are the treatments for an MCL tear?
Non-operative – majority, rest, NSAIDs, physiotherapy, brace for comfort.
Operative – severe tears, failed non-operative treatment. Repair or reconstruction. Repair: avulsions, midsubstance tear with good tissue; Reconstruction: damaged tissue.
What is Osteochondritis Dissecans?
Pathological lesion affecting articular cartilage and subchondral bone, 2 forms – juvenile (10-15 years while growth plates still open) + adult.
What are the causes of osteochondritis dissecans?
Cause – hereditary, traumatic, vascular (Adult form).
Where does osteochondritis dissecans usually affect?
Knee = most common location, posterolateral aspect of medial femoral condyle.
What are the symptoms of osteochondritis Dissecans?
Activity-related pain – poorly localised. Recurrent effusions. Locking, block to full movement.
What would you see on examination of osteochondritis Dissecans?
May be normal. LOOK – effusion. FEEL – localised tenderness. MOVE – stiffness, block to movement, Wilson’s test.
How would you investigate osteochondritis Dissecans?
X-ray – add in tunnel view (flexed 30-50 degrees)
MRI – lesion size, status of cartilage and subchondral bone, signal intensity – oedema suggest instability of fragment.
How would you treat osteochondritis Dissecans?
Non-operative – restricted weight bearing, ROM brace. Operative: arthroscopy – subchondral drilling + fixation of loose fragment, open fixation.
