Legg Calve Perthes Disease
Idiopathic ischemic necrosis of the femoral epiphysis
- Legg Calve Perthes disease is most common in children age 4-8 with a slight male predominance.
- The disease is typically unilateral, with bilateral involvement occurring in 10% of cases.
- Treatment involves monitoring and observation, weight bearing restriction, physical therapy, traction, bracing, and anti-inflammatory agents. For advanced disease surgical intervention may be indicated.
- Favorable prognosis has been linked to young age at diagnosis.
- Early referral to a pediatric orthopedic surgeon is recommended.
Signs and Symptoms:
The physical exam may demonstrate pain involving affected hip, antalgic gait, a positive anterior and lateral impingement sign owing to decreased abduction and internal rotation, respectively. There may be decreased abduction. Proximal thigh atrophy and limb shortening may be noted in advanced cases.
Radiographs may be negative during the earliest, synovitic, phase. Scintigraphy and Perfusion MRI may help identify extent of involvement and aid in early diagnosis. As the disease progresses radiographic findings are more predominant and include increased density and deformity if the femoral head epiphysis, which may appear flattened or fragmented and subluxed.
Serial radiographs every 3-4 months or more frequently during the active disease phase are integral to classification of the extent of disease as well as monitoring the disease progress. Research is ongoing regarding the prognostic value of perfusion MRI.
Progression and Prognosis:
The active disease process involves four phases: necrosis, fragmentation, reossification, and healed. During the necrotic phase subchondral fractures may appear and widening of the metaphysis may occur. During fragmentation, deformations begin to impact the epiphysis. As reossification and remodeling occur symptoms tend to subside. The long term prognosis will depend on the shape of the proximal femur at time of skeletal maturity.
Classification of disease is based on extent of femoral involvement as well as age since differing ages have differing remodeling capacities. Nonsurgical treatments include activity restriction, bracing, traction, and physical therapy. While activity restriction will not definitively inhibit femoral head collapse but can decrease effects of collapse and subluxation. This can be further minimized with braced abduction until subluxation resolves. There are surgical treatment for advanced disease include osteotomy and adductor tendon release. In all disease stages pain management and psychological well being are important considerations.
Legg Calve Perthes Disease has not been directly linked to acute trauma or infection. Due to the indolent nature of Perthes, the earliest stages may be indistinguishable from transient synovitis, however there is no evidence that transient synovitis leads to Legg Calve Perthes Disease itself. Multiple epiphyseal dysplasia, septic arthritis, sickle cell crisis, and in the case of bilateral disease process, Gaucher disease should be considered in the differential diagnosis.