Patella baja after intramedullary nailing of tibial fractures, using an infrapatellar/transtendinous approach, predicts worse patient reported outcome

Purpose After intramedullary nailing of tibial shaft fractures using an infrapatellar/transtendinous approach, several patients suffer anterior knee pain. We suspect that the approach is associated with soft tissue scars and the development of a postoperative patella baja. The goal of the study is to investigate whether the development of patella baja is associated with worse subjective outcomes. Methods We retrospectively analyzed all patients in our orthopedic trauma department between 2011 and 2020 who underwent tibial fracture fixation via intramedullary nailing via an infrapatellar/transtendinous approach. Pre- and postoperative lateral knee x-rays were evaluated by measurement of the Insall-Salvati Index, and nail tip position. All patients were asked to answer the self-assessment Kujala questionnaire and Lysholm questionnaire. Results We included 78 patients (age: 44 +/- 18 years) with a minimum follow-up of 12 months. Mean follow up was 59 +/- 25 months. We included 50 male and 28 female patients. Patella baja detected by Insall-Salvati Index could be observed in 8 (10.3%) patients. Patients with patella baja showed significant worse function measured by the Kujala score 54 +/- 18 vs. 80 +/- 14 (p < 0.01). Likewise, Lysholm score did show significant differences between both groups (60 +/- 24 vs. 86 +/- 11; p < 0.01). Nail tip position was not associated with worse subjective function. Conclusions Patella baja in patients after tibial intramedullary nailing via an infrapatellar/transtendinous approach, is associated with worse subjective function and increased pain.