884 THE JOURNAL OF BONE AND JOINT SURGERY H. Malchau, MD, PhD, Associate Professor P. Herberts, MD, PhD, Professor J. K¨ arrholm, MD, Associate Professor Department of Orthopaedics Y. X. Wang, MD Department of Diagnostic Radiology Sahlgrenska University Hospital, S-413 45, Gothenburg, Sweden. B. Romanus, MD, PhD, Associate Professor Department of Orthopaedics, East University Hospital, Gothenburg, Sweden. Correspondence should be sent to Dr H. Malchau. ©1996 British Editorial Society of Bone and Joint Surgery 0301-620X/96/61263 $2.00 LONG-TERM CLINICAL AND RADIOLOGICAL RESULTS OF THE LORD TOTAL HIP PROSTHESIS A PROSPECTIVE STUDY HENRIK MALCHAU, PETER HERBERTS, YU XING WANG, JOHAN K ¨ ARRHOLM, BERTIL ROMANUS From Sahlgrenska and East University Hospitals, Gothenburg, Sweden W e enrolled 98 patients (107 hips) with a mean age of 47 years (SD 8.6) into a prospective study of the Madreporic Lord THR; 34 hips had primary and 73 secondary osteoarthritis. After ten years, the survival rate using revision as the endpoint for failure was 70% (±9) for the cup and 98% (±0.3) for the stem. The combined clinical and radiological survival rates were 46% (±11) and 81% (±10), respectively. Osteoporosis due to stress-shielding was observed in the proximal femur. Hips with radiologically dense bone postoperatively showed the most pronounced bone loss. We recommend continued radiological follow-up of patients with this type of implant to allow revision to be performed before there is severe bony destruction of the pelvis. J Bone Joint Surg [Br] 1996;78-B:884-91. Received 4 April 1996; Accepted after revision 22 April 1996 In the 1970s Lord developed an uncemented cobalt-chro- mium implant with a fully porous (Madreporic) coated stem and a threaded cup. Initial stem fixation depended on a fit in the tight trochanteric and diaphyseal area. The preliminary results were promising (Lord 1978), but we are not aware of prospective reports of long-term series. Our aim was to assess the efficacy of this implant in a series of young and active patients over a ten-year period. PATIENTS AND METHODS Between September 1979 and November 1986 we enrolled 98 patients in the study, all of whom gave their informed consent. Nine had bilateral operations, giving a total of 107 arthroplasties. Patients were excluded if they had active inflammatory disease, severe osteoporosis, corticosteroid treatment for more than three months, a previous replace- ment of the same hip, or grossly deficient femoral or acetabular bone stock. Of the 107 hips, 34 showed primary osteoarthritis, and 33 had arthritis secondary to childhood diseases. Thirteen had old fractures of the acetabulum or femoral neck, 13 had idiopathic avascular necrosis, 7 showed inflammatory arthritis, and 7 miscellaneous disorders. Fifty-nine patients (60%) had unilateral hip disease only (Charnley group A), 28 had bilateral hip disease (group B) and 11 had multiple joint involvement (group C) (Charnley 1979). There were 40 men and 58 women with a mean age of 47 years (SD 8.6; 25 to 67) and a mean weight of 70 kg (SD 12). All the patients were operated on at the two University hospitals in Gothenburg, most of them by one of the two senior authors (PH, BR). After 1984, other uncemented implants were also used and therefore the series is not consecutive for the last two years. Clinical data and follow-up. For clinical evaluation we used a standard proforma recording age, gender, weight, diagnosis, social and working status, previous operation(s), Charnley class, subsets of the Harris hip score, implant size, peroperative assessment of bone quality and peroper- ative fracture. The Harris hip score and subsets of this score were used for outcome measurement (Harris 1969). We performed clinical and radiological examinations before and after the operation and at 1, 3, 5, 7, 10 and 13 years. For up-to-date information about revisions, espe- cially for patients who had only one component revised or had been revised after the latest follow-up, we used the National Register of THA in Sweden (Malchau, Herberts and Ahnfelt 1993). Patients were withdrawn from the study (Table I) when the cup (n = 39), the stem (n = 1) or both components (n = 1) were revised or extracted. Seven patients (7 hips) died 3 to 14 years after the operation and one patient emigrated and could not be contacted. The postoperative