Comparison of Dislocation and Outcome Between Piriformis-Sparing and Conventional Posterior Approach After Bipolar Hemiarthroplasty for Femoral Neck Fracture in Patients Over 60 Years

Abstract

Background: Hemiarthroplasty is a treatment option for femoral neck fractures in patients aged more than 60 years and postoperative dislocation after a posterior approach is not uncommon. The piriformis tendon is one of the structures providing posterior hip stability. However, evidence of piriformis-sparing approach in hemiarthroplasty is unclear regarding a reduced dislocation rate. Methods: Between January 2017 and December 2019, 321 patients underwent a posterior approach in consecutive cohorts for a hemiarthroplasty for femoral neck fractures with the minimum 24 months follow-up time (24-60 months). There were two cohorts: (1) 129 underwent the conventional posterior (CP) approach and (2) 192 underwent the piriformis-sparing (PS) approach. The differences in dislocation rate, postoperative Harris Hip Society at 1 and 2 years and other surgical complications were compared in both groups. Results: There were 6 dislocations of 129 (4.7%) underwent the CP approach and 0 dislocation from 192 underwent the PS approach that had posterior hip dislocations (P = .004). In addition, the CP group had a significantly higher mortality rate (14.7% versus 7.3%, P = .031) and lower functional outcomes as assessed by mean Harris Hip Scores at 1 year (73 versus 78, P = .005) and 2 years postoperatively (73 versus 80, P < .001) relative to the PS group. Conclusion: PS hemiarthroplasty was associated with a lower dislocation and mortality rate. Moreover, this approach gained a superior early to the mid-term functional outcome than the conventional posterior approach in elderly femoral neck fractures. Level of Evidence: II, prospective cohort study.