Rapidly destructive hip osteoarthritis
Rapidly destructive osteoarthritis of the hip, also known as rapidly progressive osteoarthritis of the hip, is a rare chondrolysis of unknown etiology which can progress to complete destruction of the femoral head. It is a diagnosis of exclusion.
Epidemiology
It is most common in middle age to elderly females in almost all reported case series.
Clinical presentation
Hip pain is the most frequently encountered symptom. In most cases, hip pain has been present for six months to three years (mean 1.4 years) .
Radiographic features
Plain film
Radiographic findings on plain film are a continuum that varies from rapidly progressive chondrolysis (> 2 mm/year or > 50% joint space narrowing/year) to complete osteolysis of the femoral head.
MRI
Described features include :
- joint effusion and synovitis
- present in 100% of patients in one report
- ill-defined bone marrow edema of the femoral head
- frequent extension to the intertrochanteric region
- present in 100% of patients in one report
- also common in the acetabulum (~ 83%)
- femoral head flattening (~ 92%)
- subchondral fracture
- subchondral cysts
Treatment and prognosis
The typical treatment is total hip arthroplasty.
Differential diagnosis
The differential diagnosis includes:
- avascular necrosis
- osteolytic metastases
- primary lytic bone lesion
- osteomyelitis
- in particular, tuberculosis or atypical mycobacteria
- CPPD arthropathy
- neuropathic arthropathy