A 13-year-old boy with an unstable slipped capital femoral epiphysis undergoes urgent in situ pinning. Which complication is he at the greatest risk of compared with a boy with a stable slip?

• A Chondrolysis
• B Premature physeal closure of the greater trochanter
• C Avascular necrosis of the femoral head ✓
• D Heterotopic ossification around the pin tract

Explanation

Stability is defined by the ability to walk with or without crutches. An unstable slip means the patient cannot bear weight, implying acute displacement with tearing of the retinacular vessels supplying the epiphysis. Avascular necrosis rates in unstable slips reach approximately 20 to 50%, far exceeding stable slips, where it is rare. Chondrolysis occurs in both groups and is linked more to joint penetration by hardware than to stability status.

Reference: Campbell's Operative Orthopaedics, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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