Garrett Breyer - Cooper Medical School of Rowan University, Camden, New Jersey, USA
Kudret Usmani - Cooper University Hospital, Camden, New Jersey, USA
Rock Hwang - Cooper University Hospital, Camden, New Jersey, USA
Brian Begley - Cooper Medical School of Rowan University, Camden, New Jersey, USA
Rakesh Mashru - Cooper University Hospital, Camden, New Jersey, USA
Christina Gutowski - Cooper University Hospital, Camden, New Jersey, USA

Objectives: To investigate the incidence and severity of knee pain following retrograde intramedullary nailing offemur fractures and to better understand functional outcomes using validated patient-reported outcome measures. Methods: Fifty-three patients with OTA ۳۲ or ۳۳ fractures treated by retrograde nail at a single academic Level ۱ trauma center between ۲۰۰۹ and ۲۰۲۰ were retrospectively reviewed. Patients verbally completed the Oxford Knee Score (OKS) and Patient-Reported Outcome Measurement Information System (PROMIS) Short Form ۶b, minimum one year postoperatively.Results: Thirty-four (۶۴%) patients reported the presence of pain. Of those reporting pain, ۱۶ (۴۷.۱%) reported their pain as mild. Compared to those without pain, patients with knee pain had lower OKS (۳۰.۳۸ +/- ۱۰.۶۵, versus ۴۱.۹۵ +/- ۶.۸۷; P <۰.۰۰۱) and higher PROMIS scores (۱۴.۶۵ +/- ۶.۷۶ versus ۱۰.۹۵ +/- ۷.۰۹; P=۰.۰۶۶). Conclusion: The increasing severity of pain was inversely correlated with functional status as measured by patientreported measures. At present, the reliability, high union rates, and otherwise low complication rates associated with retrograde femoral nailing justify its continued use. However, knee pain and functional outcomes should remain an integral part of the preoperative discussion with the patient. Level of evidence: III

Function, Femur, Intramedullary nail, knee, Pain, retrograde, Trauma