pathology

Definition

Non-traumatic or traumatic condition of femoral head with bone death

Epidemiology

20 - 50 yo (average 38)

- M: F 4:1

NHx  

70-80% with AVN will progress within 1 year

Definition 

Disorder of immune system 

- antigen-antibody complexes

- stimulate release of proteolytic enzymes

- leading to vasculitis, synovitis and cartilage destruction

Characterised

Articular Effects

- synovitis

- ligamentous and capsular laxity

- cartilage destruction

- osseous erosion

Vasculitis

- rheumatoid nodules

Definition

Dorsal Intercalated Segmental Instability / CID

Anatomy

Scapholunate joint

- C shaped

- 2-3 mm thick dorsally with transverse fibres

- thin palmar

Dorsal extrinsic ligaments

- V shaped, onto trapezium

Epidemiology

Extremely uncommon

Stability provided by joint capsule /costoclavicular & interclavicular ligaments 

Recurrent instability uncommon

Many apparent dislocations in adolescents may be growth plate injuries 

-will remodel without treatment

If OA from chronic dislocation may resect SCJ

Anatomy

C5, 6 from Upper trunk

Posterior triangle

- arises upper trunk and passes backward through posterior triangle

- under belly of omohyoid

- deep to trapezius to the suprascapular notch

Runs through suprascapular notch

Epidemiology

50% rheumatoid patients have elbow pathology

- 80% also have shoulder pathology

- 90% hand and wrist

Always consider entire upper limb

Concept

THR in dysplastic hips has a higher failure rate

- due to anatomic abnormalities

- due to generally younger age

Aim

Restore normal biomechanics and preserve bone stock

Issues

Soft tissues

Definition

Deformity characterised by 

- dorsiflexion of calcaneus 

- plantarflexion of forefoot / plantaris / forefoot equinus

Both sides of foot have elevated arch

Aetiology

Weakness of triceps surae 

- polio - most common worldwide

- spina bifida

Definition

Progressive varus deformity of knees

- secondary to abnormality of medial upper tibial physis

- localised varus & internal rotation deformity

Infantile form 

- onset 1-3 years / bilateral

Adolescent form 

Epidemiology

4th most common STS

- 10-35% of STS

Peak age 3rd-4th decade

- rare in children

Pathology

Cellular characteristics suggest tumour arises from primitive synovial cells

- rarely actually occurs within joint

Characteristic

Occasionally metastasis to lymph nodes (5-7%) 

- like Epitheloid Sarcoma