Evaluation of a technique of patellar tendon shortening to correct patella alta associated with severe crouch gait in cerebral palsy.

Abstract

This study was undertaken to evaluate the results of patella tendon shortening to correct patella alta in the context of surgery for the management of severe crouch gait. Our aim was to ascertain whether the corrected position of the patella and improvement of the power of the quadriceps were maintained for 4 years or more. Twenty older children (mean age: 14.2 years) with long-standing crouch gait secondary to cerebral diplegia underwent surgery to correct crouch gait that included the patellar tendon shortening. The technique for plicating the tendon differed for skeletally mature and immature patients. The length of the patellar tendon was measured by the Koshino Index. The strength of the quadriceps muscle was assessed by manual muscle testing and with a dynamometer and extensor lag, if present, was measured with a goniometer. In all 40 knees, the patella was brought to a more distal position and the position was maintained for a mean duration of 84 months (Koshino Index: preoperative 1.3 ± 0.10; 3-month postoperative 0.95 ± 0.05; final follow-up 0.95 ± 0.04). The results were the same for the techniques used for skeletally mature and immature patients. The power of the quadriceps improved [Medical Research Council (MRC) grade 3 to MRC grade 4] and the improvement was maintained. The technique of patella tendon shortening was effective in correcting patella alta and improving quadriceps power. The shortened patellar tendon did not stretch over the period of follow-up. Level of evidence: III.