Relapsed hip stiffness after recovery of range of motion in a hip treated for developmental dysplasia of the hip? Think again: A case report

INTRODUCTION: Several complications have been reported following treatment of developmental dysplasia of the hip (DDH). Local muscular spasm is an extremely rare complication. This case serves to enlighten orthopedists about various and unique presentations of idiopathic local muscular spasm, natural history of such condition, and appropriate treatment. PRESENTATION OF CASE: A two-year-old child presented with bilateral acetabular dysplasia for orthopedic evaluation and treated with bilateral simultaneous Dega osteotomy and postoperative cast for 12 weeks. Full range of motion (ROM) of both hips was regained three months after removal of the postoperative cast. Five months later, the child presented with apparent leg length discrepancy, and severe and painless global limitation of the right hip ROM, which initially was thought to be relapsed hip stiffness. Laboratory and radiological investigations were normal apart from pelvic obliquity on radiographs. Symptoms persisted for one month. Examination under anesthesia (EUA) was then performed and revealed full ROM of the involved hip. Physical therapy was started, and hip ROM fully recovered within 3 months without further intervention. DISCUSSION: Stiffness, which is one of the most reported complications following surgical treatment of DDH, is usually related to lengthy periods of immobilization and/or surgical treatment. Clinically, local muscular spasm of the hip can mimic stiffness. EUA is invaluable to differentiate the common postoperative stiffness from the rare local muscular spasm. CONCLUSION: Idiopathic local muscular spasm of hip might present clinically as stiffness that pose a diagnostic dilemma to the treating physician. Close observation coupled with physical therapy is sufficient.