gms | German Medical Science

Objectives: 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. Wether the development of patella baja is associated with worse subjective outcome is not known. Therefore, we hypothized that 1) there is a large number of patients with patella baja and 2) patella baja is associated with worse patient reported outcome.

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. Postoperative lateral knee x-rays were evaluated for Insall-Salvati Index, and nail tip position. All patients were asked to answer the self-assessment Kujala questionnaire and Lysholm questionnaire.

Results and Conclusion: We included 92 patients (age: 43±18 years). Mean follow up was 48±31 month. We included 61 male and 31 female patients. Patella baja detected by Insall-Salvati Index could be observed in 10 (10.8%) patients. Patients with patella baja showed significant worse function measured by the Kujala score 60±22 vs. 79±17 (p=0.022). Although the overall Lysholm score did not show significant differences between both groups (62±27 vs. 84±14; p=0.072), patients with patella baja showed significant more pain in the Lysholm score (12.14±10.74 vs. 21.2±5.77; p=0.044). Nail tip position was no individual factor for worse subjective function.

Patella baja in patients after tibial intramedullary nailing via an infrapatellar/transtendinous approach, is associated with worse subjective function and increased pain.