Legg-Calve-Perthes Disease

Populations and Risk Factors

Etiology: Exact cause of blood supply disruption to the femoral head epiphysis is unknown. Likely multifactorial
Proposed mechanisms: Thrombophilia (abnormal clotting), repeated microtrauma to the retinacular vessels, venous congestion within the femoral head, transient synovitis causing tamponade of epiphyseal vessels
Stage 1 — Ischemia/necrosis: Blood supply is interrupted. Bone cells in the epiphysis die. X-ray may show a smaller, denser femoral head
Stage 2 — Fragmentation: Dead bone is resorbed by osteoclasts. The femoral head appears fragmented and irregular on imaging. This is the stage of greatest structural vulnerability
Stage 3 — Reossification: New bone gradually replaces the necrotic and resorbed tissue. The femoral head rebuilds over months to years
Stage 4 — Remodeling: The femoral head assumes its final shape. Outcome depends on the degree of femoral head coverage by the acetabulum during healing
If the femoral head remodels as a sphere (coxa magna — enlarged but round), the prognosis is good
If it remodels as a flattened or irregular shape (coxa plana), incongruent articulation leads to early osteoarthritis
Younger children (under 6) have better remodeling potential than older children

Insidious onset of limping, often painless initially
Intermittent groin, thigh, or knee pain (referred pain to the knee is common and may be the only complaint)
Pain worsened by activity, improved by rest
Limited hip abduction and internal rotation (capsular pattern of the hip)
Antalgic gait with Trendelenburg sign (hip abductor weakness)
Thigh muscle atrophy on the affected side
Mild leg length discrepancy
Symptoms may wax and wane over weeks to months before diagnosis
Red flags: Any child with a limp and groin or knee pain should be referred for medical evaluation — do not assume a musculoskeletal cause without medical clearance

CMTO Appendix category A1 (MSK conditions)
Key concept: a limping child with knee or groin pain must be evaluated for hip pathology — knee pain can be referred from the hip
Understand the four-stage disease process (necrosis, fragmentation, reossification, remodeling)
Younger children (under 6) have better prognosis due to greater remodeling potential
Differentiate from slipped capital femoral epiphysis (SCFE), which presents in older, heavier adolescents with externally rotated limb

Pediatric population: Parental consent and presence required. Treatment must be age-appropriate
During active disease: Gentle massage to reduce muscle guarding and compensatory tension. Avoid deep pressure to the hip joint or aggressive ROM work
Goal: Pain management, reduction of hip adductor and flexor spasm, maintenance of gentle hip mobility within pain-free range
Avoid: Weight-bearing provocation, vigorous stretching, or manual traction of the affected hip
Compensatory patterns: Address contralateral hip and lumbar spine tension, gluteal weakness compensation, and altered gait mechanics
Post-surgical (osteotomy): Follow surgeon's protocol. Massage supports surrounding soft tissue recovery
Long-term: Adults with healed Legg-Calve-Perthes may develop early osteoarthritis. Treat as per OA guidelines

Legg-Calve-Perthes disease is childhood avascular necrosis of the femoral head, most common in boys aged 4-8
The disease is self-limiting over 2-5 years but may leave residual femoral head deformity causing early osteoarthritis
Knee pain in a limping child is a red flag for hip pathology — always evaluate the hip
Younger children have better remodeling potential and prognosis than older children
Massage supports pain management and compensatory tension relief but must not provoke the joint during active disease