Hinge total knee replacement revisited.
OBJECTIVE: To determine if aseptic loosening is a major problem in hinge total knee replacement. DESIGN: A cohort study. SETTING: A university-affiliated institute, specializing in elective orthopedic surgery. PATIENTS: Fifty-eight patients, mainly those requiring revision, in whom the conditions were such that it was felt only a totally constrained implant was appropriate. In 7 patients the implant was press-fitted; in the remainder it was cemented. Five patients required fusion or revision, and 8 died less than 2 years after implantation, leaving 45 for review. Follow-up was 2 to 13 years. INTERVENTION: Total knee replacement with a Guepar II prosthesis. MAIN OUTCOME MEASURES: Radiolucency determined by the Cameron system and clinical scoring using the Hospital for Special Surgery system. RESULTS: Of the cemented components, 91% of femoral stems were type IA (no lucency), 9% were type IB (partial lucency), with no type II or III lucency. Tibial lucency was 87% type IA and 13% type IB, with no type II or III lucency. Of the noncemented components, 58% of femoral components were type IA and 42% type IB. Tibial lucency was 71% type IA and 29% type IB. Lucency was mainly present in zones 1 and 2 adjacent to the knee. Clinical rating was 18% excellent, 20% good, 20% fair and 42% poor. Postoperative complications included infection (13%), aseptic loosening (7%), quadriceps lag (16%) and extensor mechanism problems (16%). CONCLUSIONS: Aseptic loosening is an uncommon problem in hinge total knee replacement. The complication rate in cases of sufficient severity as to require a hinge replacement remains high. Current indications for a hinge prosthesis are anteroposterior instability with a very large flexion gap, complete absence of the collateral ligaments and complete absence of a functioning extensor mechanism.