The effect of femoral neck-shaft angle and implant type on the accuracy of lag screw placement in extra-capsular proximal femoral fracture fixation was investigated. Radiographs of all extra-capsular proximal femoral fractures seen in one unit over 18 months were reviewed. Of 399 cases, 307 (237 female, 70 male) were included in the study as they had no contra-lateral proximal femoral metal work. Femoral neck-shaft angle (NSA) of the uninjured hip and magnification adjusted tip-apex distance (TAD) of femoral head lag screw were measured. Type of fixation implant was 135° classic hip screw (CHS) (n = 144) or 130° intra-medullary hip screw (IMHS) (n = 163). Mean contra-lateral NSA was 130.2° (112.9-148°) and 64 patients (58 female, 6 male) had a NSA <125°. Mean adjusted TAD was 18.7 mm (5.8-43.8 mm) and 88.9% of cases had a TAD of less than 25 mm. TAD values were significantly greater using an IMHS if NSA was <125° than if NSA was >125° (p = 0.028). This was not the case with the CHS. The use of the 130°-IMHS in patients with a NSA <125° leads to poorer lag screw placement than if NSA >125° and caution is advocated when using this device in such cases. © 2005 Elsevier Ltd. All rights reserved.
Walton, N. P., Wynn-Jones, H., Ward, M. S., & Wimhurst, J. A. (2005). Femoral neck-shaft angle in extra-capsular proximal femoral fracture fixation; does it make a TAD of difference? Injury, 36(11), 1361–1364. https://doi.org/10.1016/j.injury.2005.06.039