Bilateral Moore hemiarthroplasty: 36 years of good tolerance without loosening or osteolysis

We report an illustrative case of bilateral Moore arthroplasty with the clinical and radiographic results at 36 years follow-up. The femoral prostheses were implanted for necrosis of the femoral head when the patient was 46 years old. At implantation the patient's physical activity level was high (Devane 4) and remained so until retirement at age 65 years. His activity level remained high (Devane 3) to the age of 82 years when the patient suffered a Vancouver B1 periprosthetic fracture on the left. At this date, both arthroplasties were free of loosening an osteolysis. Plate fixation with wiring led to fracture healing. The Postel Merle d'Aubigné score was 17 before the fracture and 16 at healing (with a pain score of 6 both before and after). Radiographically, acetabular cartilage tolerance was excellent. This case illustrates the excellent clinical outcome obtained with the Moore hemiarthroplasty at more than 35 years despite less than satisfactory initial fixation and the absence of resurfacing. The fact that this prosthesis does not have a polyethylene element prevented the development of osteolysis which could have been expected with such a long postoperative period in this a highly active patient. Favorable factors (good abductor lever arm, adapted head diameter, resistance of the acetabular cartilage in a young subject with femoral head necrosis) may have played a role in this particular case since the excellent and sustained outcome was observed on both sides. This exceptional longevity provides useful information for better determining precise indications for head cups for the treatment of necrosis of the femoral head.