Canal fitting and treatment outcomes of patients treated with sign fin nail at a Tertiary Hospital in Tanzania

Abstract

Background: The Surgical Implant Generation Network (SIGN) Fin nail is a relatively newer design of intramedullary nails that eliminates the requirement for distal locking. While various factors influencing treatment outcomes with different nail designs have been extensively studied, limited research has focused on the specific implications of using the SIGN Fin nail. Objective: This study aimed to assess the relationship between Fin nail canal fitting and treatment outcomes in femur fractures treated with the SIGN Fin nail at Muhimbili Orthopaedics Institute. Methods: A cross-sectional study was conducted at a tertiary hospital in Tanzania. Patients who underwent femoral fracture fixation with SIGN Fin nails between January 2016 and December 2021 were recruited from the SIGN surgical database. Radiographic measurements were performed using radiant software, fracture union at one year was assessed using the mRUST score, and weight-bearing status at 6 weeks was obtained from patient records. Results: The mean canal diameter was 11.30±1.75 mm, and 82.2% had a canal fill of 80% or more. The reoperation rate was 5.9% (7/118). Although not statistically significant, patients with canal fill less than 80% had a higher rate of reoperation (p = 0.074). The union rate was 84.1% in this study, with a mean mRUST score of 9.4, and those patients with a canal fill of less than 80% were more likely to have nonunion at 1 year (p = 0.028). Pain on weight bearing at 6 weeks was reported by 42.9% (24/118) of participants, and this was significantly associated with canal fitting (p < 0.001). Conclusion: The study found the degree of canal fitting of the Fin nail to be an important factor affecting the outcomes of femoral fractures treated with SIGN Fin nails. A higher degree of canal fill was associated with better pain outcomes and lower nonunion rates.