A 10-year-old boy with previously treated bilateral Perthes disease presents with complaints of pain and early fatigue while walking. Examination reveals limited abduction and leg length discrepancy. Radiograph shows a mushroom-shaped (coxa magna) femoral head with a short broad neck. What is this deformity called?

• A Coxa valga
• B Coxa vara
• C Coxa breva
• D Coxa magna ✓

Explanation

Coxa magna describes the enlarged, mushroom-shaped femoral head resulting from overgrowth of the femoral head following Perthes disease. The head loses its spherical shape due to collapse and asymmetric healing. Coxa magna is associated with femoroacetabular impingement and early osteoarthritis. Coxa vara/valga refer to neck-shaft angle abnormalities.

Reference: Tachdjian's Pediatric Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.