Femoral nerve palsy after THA is well known, but delayed palsy is rare. We describe a 58-year-old man who had progressive thigh pain, weakness, and numbness develop 13 years after cementless arthroplasty of his left hip. Plain radiographs showed substantial liner wear. MRI of the lumbar spine was unrevealing and EMG showed a peripheral neurogenic process involving the left femoral nerve. The large intrapelvic cystic mass was confirmed by an abdominopelvic CT scan. Percutaneous aspiration of the cyst was performed. Cultures of the fluid were negative and cytopathologic examination showed necrotic debris without malignant cells. Biopsy revealed necrosis and abundant foreign body granulation tissue with polarizable debris. During surgical removal of the cyst, a defect of the inner acetabular wall was noted. After subsequent revision arthroplasty with allograft bone, the patient’s clinical symptoms improved and his EMG returned to normal.

From a total of 153 patients (251 feet), 64 (41.8%) patients, who had had 105 modified Mitchell procedures, were clinically and radiographically examined with follow-up periods ranging from 15 to 24 years (mean, 21 years). Mean age at operation was 41 years (range, 12–64 years). The classic double osteotomies, which diverged slightly toward the plantar surface and the distal fragment, shifted laterally, and angled plantarward, were fixed with a smooth Kirschner wire. In this way, it was possible to achieve a reduction in the first intermetatarsal angle from an average of 22.5° preoperatively to 7.7° postoperatively, and the hallux valgus angle changed from an average of 33° to 17°, with an average shortening of the first metatarsal of 5.4 mm and an average lateral displacement of the first metatarsal head of 4.5 mm. In 67 feet (64%), the results were graded good to excellent; in 23 feet (22%), satisfied; and in 15 feet (14%), poor. The results were worse than the results obtained on the same patient population with a follow-up ranging from 2 to 11 years, with 97% good-to-excellent results reported. Pain over bunion caused by recurrence of the hallux valgus deformity was the main reason for this late deterioration of the results.