Experience with a hydroxypatik-coated and macroporous-surfaced hip prosthesis

Introduction: Cementless hip arthroplasty is not completely satisfactory - even with macroporous structured surface. Medium term results are sometimes disappointing because of insufficient secondary stability. Thus our aim wa s to improve fixation by additional coating with hydroxyapatite. Methods: 200 consecutive patients who had hydroxyapatite-coated cementless hip replacement with a macroporous hip prosthesis (09/92-03/96) were studie d prospectively. All patients were included in a prospective follow up sche dule according to the criteria of Johnston et al. As measure of clinical ou tcome we calculated Harris Hip Score as well as Enghs Score to assess radio logic fixation and stability. Results: 91% could be followed up regularly. No revision because of aseptic loosening had to be done. Analysis of clinical results showed almost painl ess patients from early after the operation - especially no thigh pain. ave rage HHS after 2 years was 97. Radiological evaluation showed early and com plete osteointegration of all components. According to Engh-Score they are stable and well fixed. Conclusion: HA coated macroporous implants provide some striking advantages , which encouraged us to continue with this system. By early and secure bon y ingrowth a fibrous interface is avoided and thereby also long-lasting thi gh pain.