Patella alta and recurrent dislocation of the patella.

Fifteen knees were treated with a surgical technique designed for recurrent patellar dislocations when associated with patella alta. The average number of patellar dislocations preoperatively was 12, and the determination of patella alta was made using the technique described by Insall and Salvati, which is a ratio of the length of the patellar tendon to the longest diagonal length of the patella. The normal value for this ratio is 1.02 plus or minus 20%. The average preoperative ratio in this study was 1.58 (range, 1.2-2.1), which changed to 1.08 (range, 0.99-1.14) by the time of follow-up examination. The surgical technique used involves transposing the patellar tendon insertion distally without any medialization or recessing and allows for good bone contact for healing, secure fixation, and immediate postoperative motion. There were no recurrences of patellar dislocation postoperatively and few complications. Only one patient complained of anterior knee pain in the follow-up period. This technique is thought to give good results when it is used specifically for recurrent patellar dislocations associated with patella alta.