natural history

Definition

Osteochondritis Dissecans

- separation of avascular fragment of bone & cartilage

Epidemiology

M : F = 2:1

Mean age 18 years

- can present as young as 9

4:1000

NHx

Natural History of ACL deficient knee is variable

- functional instability 15% - 90%

- progression to OA is variable

Depends on level of patient demands / activity

1.  Late meniscal injury in ACL deficient knee

15-25%

2.  Function

Daniels Am J Sports Med 1994

- 292 ACL defecients knees

Incidence

Most common lower limb neuropathy

Aetiology

Valgus TKR - 3%

HTO - 10%

Direct Trauma / Compression

Knee Dislocation

Tibial fracture

Cast / Dressing

Lateral Meniscus Repair

SONK              vs                          Atraumatic AVN

>55                                              Often mid 30's

Definition

Idiopathic condition of the immature femoral capital epiphysis involving varying degrees of osteonecrosis

AKA

- Legg-Calve-Perthes disease

- coxa plana

Described in separate publications in 1912 by

- Legg (Boston)

- Calve (France)

- Perthes (Germany)

Epidemiology

M: F    4:1

1 in 740 males

Epidemiology

70% male

70% positive FHx

20% learning difficulties

DDx toe walking

Early / late onset

Unilateral  / bilateral

1.  Habitual

Toddlers - child can heel walk

2.  Structural

Fixed equinus - CTEV / arthrogryposis

Short / tight T Achilles

Space occupying lesion in calf

Definition

Metatarsus varus

- adduction of the forefoot at the TMTJ

Intrauterine positional deformity / packaging defect

Epidemiology

1:1000

- M = F 

- bilateral in 50%

- 10% have CDH

Aetiology

Unclear

Theories

- intrauterine positioning defect

- prone nursing

Definition

Malignant Fibrous Histiocytoma

Characterised by heterogenous population of pleomorphic spindle cells

- organised in a characteristic storiform or "starry night" pattern

Cell of origin unknown 

- primitive mesenchymal cell

- allowing both features of a macrophage (hence histiocyte)

- and collagen producing cell (hence fibroblast)

Epidemiology

Epidemiology

Uncommon

- 4% OS

Females more common 

- similar to GCT

NHx

Less aggressive locally

- less metastasis

- size / location & duration of symptoms don't correlate with outcome

Arise from cortex of bone / periosteum

- parosteal 

- periosteal

- high grade juxtacortical

AKA

Non Ossifying Fibroma

Definition

A hamartomatous defect in the metaphyseal cortex of skeletally-immature adolescents

Fibrous cortical defect 

- < 2cm in diameter

Non ossifying fibromas 

- > 2cm

Aetiology