[Etiology, diagnosis and therapy of aseptic hip prosthesis loosening--a status assessment]

Aseptic loosening of prostheses implants is the most common complication of hip replacement surgery and represents an increasing problem because of still rising numbers of primary arthroplasties. This study reviews the current scientific status of causes, diagnosis and therapeutical concepts on this theme in literature.

We analyzed 6,386 cases on aseptic hip revision arthroplasties published in the international literature and separated the results for cup and femoral components. On this basis we deduced some recommendations for the operative procedure in aseptic hip revision surgery.

The mean follow-up time of all studies was 6.8 years in the case of cemented and 4.0 years in the case of uncemented hip revision arthroplasty. As an average rate of rerevision, 15.1% was calculated for cemented cup revisions, 4.3% for uncemented cup revisions. Rates of aseptic loosening were 23.1% for cemented procedure, 8.8% for uncemented cup implants. Femoral revision implants showed an average aseptic loosening rate of 21.2% for cemented procedures and an average rate of rerevisions of 12.7%; uncemented procedures showed aseptic loosening in 4.4% of the cases and rerevision in 5.5%. For old, relatively immobile patients with reduced physical constitution, cemented reimplantation has still to be regarded as the method of choice. In young patients uncemented revision arthroplasty is to prefer both on the acetabular and the femoral side to achieve superior results with good long-term prognosis. Regarding the bony defects induced by loosening, bone grafting is recommended for cemented and uncemented reimplantation technique.

In the case of aseptic hip revision arthroplasty, the therapeutical procedure has to be adapted especially to the age and general constitution of the patient as well as to the bony defects induced by prosthetic loosening. For the future, controlled studies should respect the initial condition of primary as well as revision arthroplasty in reporting the results.