Common conditions of the knee Flashcards
Key ligaments within the knee?
Cruciate ligaments:
- ACL
- PCL
Collateral ligaments:
- MCL
- LCL
What are the menisci of the knee?
> Specialised C-shaped cartilage:
- Triangular in cross-section
- Medial = attached to deep MCL
- Lateral
> Function:
- AID force transmission
- Increase stability
What can cause a meniscal tear?
> Acute = Twisting especially in deep flexion
> Degenerative = Osteoarthritis
> Medical meniscal tears more common
What is the significant difference between an acute and a degenerative MCL tear?
Degenerative is not repairable where as acute is
How does someone present with a meniscal tear?
> Pain
Clicking
Locking
Intermittent swelling
Meniscal tear examination?
1) Look - effusion
2) Feel:
- Tender joint line at point of tear (esp medial tear)
3) Move:
- Mechanical block to movement
- McMurrays test positive
- Fail deep squat
- Thassaly’s test positive
Meniscal tear investigations?
X-ray
- Arthritis
- Fracture
MRI
- Most sensitive test
- High False positive rate
Meniscal tear management?
Unlikely to heal due to poor blood supply
Non-operative
- Rest
- Nsaids
- Physiotherapy
- Hamstring and Quadriceps strengthening
Operative
- Arthroscopy = Repair or
resection
What is osteoarthritis?
Degenerative change of synovial joints
Progressive loss of articular cartilage
Secondary bony changes
Characteristic presentation of osteoarthritis?
Characterised by worsening pain and stiffness of the affected joint that gets worse with activity and better with rest
Blood supply to the ACL?
Middle geniculate artery
innervation of the ACL?
Posterior articular nerve a branch of the 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
How is the ACL usually torn?
Non-contact pivot injury
Presentation of an ACL tear?
Heard a ‘pop’ or ‘crack’
Immediate swelling (70%)
haemarthrosis
Unable to continue playing
Can walk in straight line but hurts to turn
Deep pain
Examination ACL tear?
1) Look = Effusion (if recent injury)
2) Feel
3) Move
- Anterior draw
- Lachmann’s test
- Pivot shift = Best done under anaesthetic
Investigations for an ACL tear?
X-ray
- Segond fracture
- Avulsion # of anterolateral ligament
MRI
- ACL
- Meniscii
> Lateral – simultaneous with acl tear (48%)
> Medial – secondary to shear from chronic instability
- MCL
ACL treatment?
Non-operative = Focussed quadricep programme
Operative= ACL reconstruction:
> +/- partial menisectomy +/- ligament repair or augmentation
> Hamstring graft
What is the most common ligament injury of the knee?
The MCL (Medial collateral ligament?
How does MCL tear usually occur?
Sever valgus stress, usually from contact
Associated injuries with MCL tear?
- ACL tear
- Meniscal tear
Presentation of a MCL tear?
> Heard a ‘pop’ or ‘crack’ > Pain ++ on Medial side > Unable to continue playing > Bruising medial knee > Localised swelling
Examination of 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
Investigations for MCL tear?
X-ray
- May be normal
- Calcification at femoral insertion (Pellegrini-stieda), Chronic injury
MRI
- Modality of choice
- Assess location and severity of injury
- Identify other pathologies (ACL, menisci)
Management of MCL tear?
Non-operative
- Majority
- Rest and NSAIDs
- Physiotherapy
- Brace for comfort
Operative
- Severe tears
- Failed non-operative management
- 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:
1) Juvenile = 10-15 years while growth plates still open
2) Adult
Causes of osteochondritis dissecans?
Cause
- Hereditary
- Traumatic
- Vascular = Adult form
Most common location of osteochondritis dissecans?
Knee = most common
Posterolateral aspect of medial femoral condyle (70%)
Presentation of osteochondritis dissecans?
- Activity-related Pain., Poorly localised
- Recurrent effusions
- Mechanical symptoms
> Locking
> Block to full movement
Examination of osteochondritis dissecans?
- May be normal
Look
- effusion
Feel
- Localised tenderness
Move
- stiffness
- Block to movement
- Wilson’s test
Investigations for osteochondritis dissecans
X-ray
- Add in tunnel view (flexed 30-50 deg)
MRI
- Lesion size
- Status of cartilage and subchondral bone
- Signal intensity, Oedema suggests instability of fragment
Management of osteochondritis dissecans?
Non-operative
- Restricted weight-bearing
- Rom brace
Operative
- Arthroscopy
- Subchondral drilling
- Fixation of loose fragment
- Open fixation
