21: Orthopaedic Knee Conditions Flashcards
label the ligaments and menisci of the knee joint
what is the function of meniscii?
- specialised c-shaped cartilages which aid force transmission and increase stability of the knee joint
are medial or lateral meniscus tears more common?
medial
meniscal tear presentation and examination clues
use LOOK, FEEL, MOVE for exam clues
presentation:
- pain
- clicking
- locking
- intermittent swelling
examination:
- LOOK: effusion
- FEEL: tender joint line at point of tear (esp. medial tear)
- MOVE: mechanical block to movement, McMurrays test +, fail deep squat, Thassaly’s test +
meniscal tear investigations
- history and exam
- x-ray: arthritis, fracture
- MRI: most sensitive test, high false positive rate
meniscal tear treatment
Unlikely to heal as poor blood supply
Non-operative:
- rest
- NSAIDs
- physio: hamstring and quads strengthening
Operative:
- arthroscopy: repair or resection
what happens in osteoarthritis?
degenerative change of synovial joints:
- progressive loss of articular cartilage
- secondary bony changes
characterised by worsening pain and stiffness of the affected joint
what are the conservative management options for osteoarthritis?
- weight loss
- analgesia
- activity modification
- braces
- walking aids
- visco-supplementation
- steroid injections
what is the anterior cruciate ligament (ACL) blood supply?
middle geniculate artery
what is the innervation of the ACL?
posterior articular nerve, a branch of tibial nerve
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 typically causes an an ACL tear and what gender does it usually affect?
- non-contact pivot injury
- females:males = 4.5:1
ACL tear presentation
- hard a ‘pop’ or ‘crack’
- immediate swelling (70%) and haemarthrosis
- unable to continue playing but can walk in straight line
- deep pain
ACL tear examination clues
USE LOOK, FEEL AND MOVE
- LOOK: effusion (if recent injury)
- FEEL: may be tender
- MOVE: anterior draw, Lachmann’s test, Pivot shift > best done under anaesthetic
ACL tear imaging
- x-ray: segond fracture > avulsion of anterolateral ligament
- MRI: ACL, meniscii (lateral simultaneous with ACL tear (48%)) medial secondary to shear from chronic insatbility, MCL
ACL tear treatment
non-operative:
- focused quadricep programme
operative:
- ACL reconstruction: +/- partial menisectomy +/- ligament reoaur or augmentation, hamstring graft
what is the function of the superficial medial cruciate ligament (MCL)?
- primary restraint to valgus stress
what is the function of the deep medial cruciate ligament MCL?
- contributes in full knee extension
- attaches to medial meniscus
- continuous with joint capsule
what is the most common ligament injury of the knee?
MCL tear
what usually causes an MCL tear?
severe valgus stress
- usually contact-related
MCL tear presentation
- heard a ‘pop’ or ‘crack’
- pain ++ medial side
- unable to continue playing
- bruised medial knee
- localised swelling
MCL tear examination clues
LOOK, FEEL, MOVE
- LOOK: medial swelling and bruising
- FEEL: tender medial joint line, tender femoral insertion of MCL
- MOVE: painful in full extension, opening on valgus stress
MCL tear investigations
- history and exam
- x-ray: may be normal, calcification at femoral insertion
- MRI: modality of choice, assess location of injury and identify other pathologies
MCL tear treatment
non-operative:
- rest
- NSAIDs
- physio
- brace for comfort
operative (for severe tears, or failed non-operative management):
- repair: avulsions for midsubstance tear with good tissue
- reconstruction: for damaged tissue
describe osteochondritis dissecans
- pathological lesion affecting articular cartilage and subchondral bone
- 2 forms: juvenile (10-15 years while growth plates still open) and adult
- posterolateral aspect of medial femoral condyle (70%) of cases in knee
causes for osteochondritis dissecans
- hereditary
- traumatic
- vascular: adult form
osteochondritis dissecans presentation
- activity-related pain, poorly localised
- recurrent effusions
- mechanical symptoms: locking, block to full movement
osteochondritis dissecans examination clues
LOOK, FEEL, MOVE
- LOOK: effusion
- FEEL: localised tenderness
- MOVE: stiffness, block to movement, Wilson’s test
osteochondritis dissecans investigations
- history and exam
- x-ray: add on tunnel view (flexed 30-50 degrees)
- MRI: lesion size, status of cartilage and subchondral bone, signal intensity > oedema suggests instability of fragment
osteochondritis dissecans treatment
non-operative:
- restricted weight-bearing
- ROM brace
operative:
- arthroscopy: subchondral drilling, fixation of loose fragment
- open fixation
