Knee Flashcards
Ligaments of knee
Medial/ lateral collateral ligament
Anterior/ posterior collateral ligament
ACL injury
Landing or sudden deceleration - strong quadricep contraction with valgus collapse and femur internal rotation
Hyper-extension - femur posteriorly slides behind tibia with quadriceps contraction
Twisting injury - changing direction
Meniscal injury mechanism
Twisting injuries whilst felxed and weight bearing
Symptoms of meniscal injury
Locking and giving way
Unhappy triad
Trauma to lateral knee causes tear of:
- medial collateral ligament
- medial meniscus
- ACL
Special tests to assess ACL
Anterior drawer test
Lachman’s test
PCL injury mechanism
Dashboard injury
Fall on front of knee
Medial collateral ligament mechanism of injury
Valgus stress
Skiing
Baker’s cyst
Bulge and feeling of tightness behind knee
Cause - knee trauma, OA, inflammatory arthritis, gout
Foucher’s sign
Increase in tension of Baker’s cysts on extension of knee
Infrapatellar bursitis
When kneeling on knees like praying
- Clergyman’s bursitis
Prepatellar burstis
When kneeling on hands and feet
- housemaid’s bursitis
ACL surgery
Gold-standard is autograft repair
• Usually semitendinosus ± gracilis (can use patella
tendon)
Osteochondritis Dissecans
• Piece of bone and overlying cartilage dissects off into
joint space.
• Commonly knee (med. fem. condyle), also elbow, hip and ankle.
• Young adult / adolescent
• Symptoms: pain, swelling, locking, ↓ ROM
• X-ray: loose bodies, lucent crater
• Mx: arthroscopic removal
Knee OA presentation
Pain around knee - can radiate to thigh and hip
Crepitus
Pain exacerbated by exercise and relieved by rest
Joint stiffness - reduced ROM
Mx of knee OA
Lifestyle modification
Total knee replacement - gold standard
ACL injury presentation
Immediate swelling
Significant pain
Segond injury
Bony avulsion of the lateral proximal tibia - pathognomic of ACL injury
Ix for Meniscal tears MCL, PCL and ACL injury
Xray - rule out other causes
MRI scan - gold standard
ACL injury mx
RICE
Conservative - splint and rehab
Surgical - tendon or artifical graft
Presentation of medial collateral ligament injury
May pop Immediate medial joint line pain Swelling after hours Tender along joint line May be able to weight bear
MCL injury mx
RICE
Strength training for 6 weeks
Analgesia
Grade II - moderate injury, with an incomplete tear:
- knee brace, strength training for 10 weeks
Grade III - severe injury, with a complete tear :
- Knee brace, crutches, strength training for 12 weeks
Indication for surgery in medial collateral ligament injury
Distal avulsion on MRI
Medial meniscus
Less circular than lateral meniscus
Attached to MCL
Purpose of menisci
Shock absorber
Increase articulation surface area
Types of meniscal tear
Longitudinal - bucket handle - central tear separates from lateral fragment
Vertical
Transverse (Parrot-beak)
Degenerative
Clinical features of meniscal tears
Tearing sensation in the knee
Intense sudden onset pain
Swells slowly - 6 - 12 hours
Locked in flexion - unable to extend
Tenderness
Joint effusion
Test for meniscal tears
McMurray’s Test* and Apley’s Grind Test
Mx of meniscal tears
RICE
Larger tears - arthroscopy
If tear is in outer third - can be sutured
Inner third - trimmed
Complications of meniscal tears and tx
OA
Arthroscopy can cause - DVT, damage to local structures such as the saphenous nerve and vein, the peroneal nerve, and the popliteal vessels
Clinical features of patella fracture
Anterior knee pain
Worse with movement
Unable to straight leg raise
Swollen and bruised
Patella defect
Bipartite Patella
Congenital condition whereby there is failure of patella fusion, leaving two separate bone fragments of the patella joined only by fibrocartilaginous tissue
- asymptomatic
Ix for patella frcature
Xrays - AP, Lateral , skyline
CT
Mx of patella fractures
Non displaced, minimally displaced - conservative
- RICE
- brace or cylinder cast- early weight bearing in extension
Displaced or compromised extension - surgery
- ORIF with tension band wiring
- screw fixation if simple fracture
Complications of patella fractures
OA
Loss of ROM