Evaluating the efficacy of set screw utilization during cephalomedullary nail treatment of peritrochanteric femur fractures

Abstract

Introduction: Deployment of set screws with cephalomedullary nails (CMNs) may control rotation and/or dynamization of peritrochanteric femur fractures. We hypothesize equivalent radiographic and ambulatory outcomes for patients treated with CMNs for peritrochanteric femur fractures regardless of set screw use. Methods: CPT code 27245 was utilized to retrospectively identify patients treated with a CMN for peritrochanteric femur fractures at our institutions between January 2011 and December 2017. Of 581 patients identified, 217 met the inclusion criteria. CMN fixation of peritrochanteric femur fractures with and without set screw utilization were compared with respect to fracture collapse and ambulatory status. Results: The difference between mean intra-operative and post-union lateral screw protuberance (▲LSP) were 3.62mm and 2.26mm in the no set screw (NSS) and set screw (SS) groups, respectively. Thus, the NSS group on average had 1.36mm greater fracture collapse than the SS group (p = 0.007) with a LLD of 0.88mm. The relative risks of ambulatory status decline were 0.93 (95 % CI = 0.66–1.31) and 1.74 (95 % CI = 0.41–7.21) when comparing SS to NSS groups in pre-injury independent and cane/walker dependent patients respectively. Discussion/conclusion: Patients who were treated with CMNs without utilization of a set screw had greater fracture collapse compared to patients who underwent set screw deployment. The average difference in fracture collapse of 1.36mm had a resultant difference in leg length difference (LLD) of only 0.88mm. Clinical outcomes, however, as measured by gross ambulatory did not appear to be affected by this change in LLD but studies with larger patient populations are needed to accurately conclude this observation.

Keywords

• Set screw
• Cephalomedullary nail
• Hip fractures
• Peritrochanteric femur fractures
• Lateral screw protuberance