Migration analysis of a metaphyseal anchored short-stem hip prosthesis.
OBJECTIVE
Metaphyseal anchored short-stem hip implants were designed to improve load transmission and preserve femoral bone stock. Until now, only few outcome data have been available and migration studies are one of the few ways of obtaining data that are predictive of implant survival. We therefore evaluated a metaphyseal anchored short-stem hip implant by Ein Bild Roentgen Analyse femoral component analysis (EBRA-FCA).


METHODS
First, the EBRA-FCA method was validated for the short-stem hip implant. Then 80 of the first 100 consecutive implants were evaluated after at least 2 years. Clinical assessment was performed using the WOMAC and the UCLA score.


RESULTS
After 2.7 (2.0-4.2), years none of the implants had been revised and by that time the stems had subsided by a mean of 0.7 mm (SD 1.8) (95% CI: 0.3-1.1). Of the 80 implants, 78 were stable after 2 years, with 74 being primary stable and 4 showing secondary stabilization after initial subsidence. Continuous migration was seen in only 2 patients. The clinical outcome showed good results with a mean WOMAC of 11 (SD 13) and a mean UCLA score of 7.3 (SD 2.0).


CONCLUSIONS
The metaphyseal anchored short-stem hip implant showed good functional results and a high degree of stability after 2 years. The outcome is comparable to that of clinically proven conventional hip implants and if the results are confirmed by long-term studies, short-stem hip arthroplasty might be an alternative for young patients requiring hip replacement.
Departments of Orthopedic Surgery, University of Munich, Campus Grosshadern, Germany. florian.schmidutz@med.uni-muenchen.de
Florian
F
Schmidutz
Thomas
T
Graf
Farhad
F
Mazoochian
Andreas
A
Fottner
Andrea
A
Bauer-Melnyk
Volkmar
V
Jansson
D000328:Adult; D017677:Age Distribution; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006621:Hip Joint / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D015994:Incidence; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000453:epidemiology; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology / Q000503:physiopathology; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D018570:Risk Assessment; D017678:Sex Distribution; D013997:Time Factors; D016896:Treatment Outcome