A femoral component with proximal HA coating. An analysis of survival and fixation at up to ten years.
We describe the survival at ten years of 100 femoral components of the Freeman hip prosthesis. It is proximally hydroxyapatite (HA)-coated and was fixed without cement. Radiological assessment identified radiolucent lines (RLLs) and lytic lesions and was used to measure migration. The criterion of failure was revision or impending revision for aseptic femoral loosening. No femoral components were revised or are awaiting revision for aseptic loosening, giving 100% survival at ten years (95% confidence interval, 95.7 to 100), although 59 were at risk at ten years. Two components were revised for fracture of a ceramic head with damage to the trunnion. Although well fixed in each, for survival analysis we evaluated the hip as if the patient had died. Twelve acetabular components were revised and at each operation the femoral component was found to be well fixed, was not disturbed and remained in the survival analysis. Three patients were lost to follow-up, and 12 died with well-functioning prostheses. Radiologically, all except one of the components appeared to be well fixed with no RLLs and no lytic lesions at the latest follow-up. The mean vertical migration was 0.4 mm at one year, 0.8 mm at two years and 1.4 mm at ten years. One component had migrated 7.6 mm at ten years (2.1 mm in year 1) and developed RLLs in Gruen zones I and II. The symptoms, however, were only minor and revision was not indicated. Our study has shown that proximal HA coating gives effective fixation for a femoral component.
Royal National Orthopaedic Hospital and the Royal London Hospital NHS Trust, London, England, UK.
J A
JA
Skinner
P O
PO
Kroon
S
S
Todo
G
G
Scott
D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging / Q000601:surgery; D019644:Arthroplasty, Replacement, Hip; D001672:Biocompatible Materials; D017886:Durapatite; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000601:surgery; D005500:Follow-Up Studies; D025981:Hip Injuries / Q000000981:diagnostic imaging / Q000601:surgery; D006621:Hip Joint / Q000000981:diagnostic imaging; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000601:surgery; D011474:Prosthesis Design; D011475:Prosthesis Failure; D019919:Prosthesis Implantation / Q000379:methods; D011859:Radiography; D012307:Risk Factors; D016019:Survival Analysis; D016896:Treatment Outcome
D001672:Biocompatible Materials; D017886:Durapatite