Prognostic factors for the efficacy of anteromedial tibial tubercle transfer in the treatment of patellar subluxation with patellofemoral osteoarthritis

Objective:To investigate the effect and prognostic factors of the operation of anteromedial tibial tubercle transfer on patellar subluxation with patellofemoral osteoarthritis.Method:Between Jun.1995 and Nov.2002,patients who had patellar subluxation with patellofemoral osteoarthritis were treated by anteromedial tibial tubercle transfer,lateral retinacular release,debridement and spongialization.Forty-three patients (57 knees) had been followed up.Pre-and postoperative evaluations included clinical symptoms,radiographic examinations and modified Lysholm patellofemoral scores.Result:The average followup were 35 months.All of the followed-up patients had 84% good to excellent subjective results.The modified Lysholm scores improved an average of 34 points,from an average of 49 preoperatively to 83 postoperatively.The good to excellent objective results was 81%.Sex,side,age,duration of follow-up,combination with patella alta were of no significant effect on outcome.Patients with Wiberg Ⅱ patella and those combining with patella tilt tended to have more excellent outcome,but the difference was not statistically significant.Patients with chondral lesions of the overall patella,degenerative changes of tibiofemoral joint or duration of symptoms more than ten years got poor outcome.Conclusion:Anteromedial tibial tubercle transfer produces a relatively favourable outcome in patients having patella subluxation with patellofemoral osteoarthritis.Chondral lesions of the overall patella,degenerative changes of tibiofemoral joint and duration of symptoms more than ten years are poor prognostic factors of this procedure.