The effects of patellar tendon advancement on the immature proximal tibia

The aim of this study is to examine the short-term effects of patellar tendon advancement on the proximal tibial slope in the skeletally immature patient.

A retrospective, non-randomized, comparative cohort design was used. Koshino indices and tibial slopes were assessed pre-operatively and post-operatively and compared with age- and sex-matched controls.

Nine children with 17 patellar tendon advancements were analyzed for changes in Koshino indices. Of these 17 tibiae, radiographs on changes in tibial slope were available for 16 tibiae which were also compared with controls. Children aged <11 years had a greater initial posterior tibial slope (69.8° ± 3.5°) than age-matched controls (80.3° ± 2.7°). A decrease in posterior slope was seen in these younger patients (average change 10.3° ± 4.8°) at an average of 1.6 years of follow-up. Of the nine apophyses in children aged <11 years of age, seven had undergone premature closure.

Patellar tendon advancement appears to have an unreported effect on the proximal tibial growth in the young patient (<11 years old). These patients appear to be susceptible to apophyseal closure, resulting in subsequent loss of posterior tibial slope. Surgeons should be aware of this effect and monitor younger patients with radiographs if performing this procedure.