Traumatic initial cause in 95%
M:F 2:1
Age of initial dislocation inversely related to recurrence rate
- patients younger than 20 have a redislocation rate of 90%
- between 20 - 40 years, redislocation rate of 60%
- patients > 40 years have a 10% rate of dislocation but a higher rate of cuff tears (up to 40% in patients > 60yrs)
Post-traumatic (type III clavicle fractures)
Idiopathic
1. OA with osteophytes
- contribute to impingement
2. Osteolysis with resorption & gross osteoporosis
Injury to ulnar collateral ligament of thumb MCPJ
Initial description
- chronic laxity of British gamekeeper's thumb's
- no specific trauma
- secondary to breaking pheasant's neck
Acute trauma
- snow ski
- ball games
Valgus / forced abduction
UCL
Adolescents & young adults
Usually between 12 - 21 years
Throwing athletes / gymnasts
Little Leaguer's Elbow
- combination of capitellar OCD and MCL injury
- a repetitive throwing injury / seen in pitchers
1. Trauma & Overuse
Common throwing sports / gymnastics
Lateral : Medial 9:1
4th & 5th decades
- M = F
- 75% dominant arm
50% of regular tennis players
- especially > 2 hrs / week
Insertion pathology / Enthesopathy
Over-extension of the elbow with supination / pronation
Lateral epicondyle
- anconeus from posterior face
- ECRB and EDC from anterior face (CEO)
Dominant arm of middle aged men
- between 40 and 60
Sudden dramatic event
- sporting / weightlifting injury
- resisting heavy extension load
Degenerative changes seen on histology
Complete
- retracted / rupture of lacertus fibrosis
- minimally retracted
Usually occurs in young people
- often previous history of tendonitis ± steroid injections
Usually at level of inferior pole of patella
- less common at tibial tubercle
- mid-substance ruptures rare
Severe pain
Palpable defect
Extensor deficit / unable to SLR
Patella alta / high riding patella
Osteochondritis Dissecans
- separation of avascular fragment of bone & cartilage
M : F = 2:1
Mean age 18 years
- can present as young as 9
4:1000
Most common in lateral meniscus 9:1
Peak incidence 20-40
Probably 2° to infiltration of joint fluid into extra-articular tissues
- almost always associated with horizontal cleavage tear
- creates a flap valve in lateral 1/3 of LM
Usually present with pain
- activity related
May notice lump
Rotational force incurred while joint partially flexed & extending
- caught between femoral & tibial condyles
- usually valgus & ER / varus & IR