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

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 

Definition

STS composed of malignant lipoblasts

Epidemiology

Common 

- 10% of STS

- second only to MFH

Occurs almost exclusively in adults

Males age 40-60

Can be multiple origin -> examine patient

Rarely arise from lipoma

Definition

Schwannoma

- benign tumour of nerve sheath

Epidemiology

Less common than neurofibroma

- occurs in adults

- can occur along any peripheral nerve

- also can occur along a nerve root

Usually a large nerve

More common in forearm

Seen in NF 2 

- acoustic Schwannoma