We have followed up for a period of seven to nine years 100 consecutive arthroplasties of the hip in which an entirely HA-coated implant had been used. The clinical results were excellent and bony incorporation was extensive in all components. No stem became loose or subsided but five cups were revised because of loosening after 3.8 to 5.5 years, having functioned painlessly and shown radiological ingrowth. Revision procedures because of excessive polyethylene wear have been performed on 18 hips and are planned for six more. Two eroded metal backings with worn-through polyethylene were exchanged; six hips showed metallosis without polyethylene wear-through. There were two cases of granulomatous cysts in the groin and 66 hips had osteolysis located periarticularly, in the greater trochanter or in the acetabulum.

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We compared radiographically the femurs for 5 years after cemented (Landos Titane) and uncemented (Zweymüller/Endler) hip arthroplasty (THA) for coxarthrosis in 120 patients. The bone changes followed a characteristic time-course with rapid initial remodeling and almost no further changes after 3-4 years. No association between bone changes and clinical results was found. The groups did not differ in bone atrophy and ectopic bone formation, whereas the incidence of distal cortical hypertrophy and proximal radio-opaque double line was higher around uncemented stems. The age and body weight of the patients and the stem size did not affect the bone changes, but women with uncemented stems developed more bone atrophy than did men.

A prospective comparative study was made of patients in the age-group 60-79 years with osteoarthritis of the hip treated with the Müller total hip prosthesis (n = 155) and the ICLH double-cup prosthesis (n = 149). The patients were comparable with regard to sex, mean age, and body weight, and the preoperative radiographic appearance of the hips was th same in the two groups. The mean operating time was significantly shorter in the Müller group, whereas the operative blood loss and the operative complications were statistically equal. No deep infections occurred in either group. The incidence of systemic complications was low and no difference between the two groups was seen. The patients are followed up for an average of 48.5 months (range: 27-75 months). Dramatic improvement in hip function was seen postoperatively in both prosthetic groups. The Müller group had more favorable ratings than the ICLH group for pain, walking ability, hip motion, and total hip score at all follow-ups, from 3 weeks to 5 years after the operation. However, the differences were rather small and did not reach a significant level at any registration. The acetabular radiolucent zones and heterotopic bone formation were statistically equal in the two groups. No revision operations have been done in the Müller group. Two Müller prostheses have shown radiographic signs of mechanical loosening. Thirteen ICLH prostheses (8.7%)--all in female patients--have been reoperated (P less than 0.001), 12 owing to mechanical loosening and one because of pain and stiffness.(ABSTRACT TRUNCATED AT 250 WORDS)