Introduction: A superior approach (SA) for the hip joint differs from other approaches on not taking over the range leg position. We investigated the rate of preservation of the short rotator muscles, intraoperative fractures (IOFs), and postoperative dislocations among patients who underwent hip arthroplasty using the SA. Additionally, we investigated factors associated with muscle-preserving total hip arthroplasty (THA).
Methods: The study included patients who underwent hip hemi-arthroplasty and THA using the SA between January 2016 and December 2019. We analyzed patient records to confirm IOFs and preservation vs. resection of the short rotator muscles. We recorded the postoperative dislocation rates until February 2020. We evaluated preoperative plain radiographs to measure the distance between the lesser trochanter and the ischium. Logistic regression analysis was used to analyze the factors associated with short rotator muscle preservation.
Results: Hip hemi-arthroplasty for femoral neck fractures was performed in 138 patients. The mean operation time was 64min. The mean intraoperative blood loss was 143g. IOFs occurred in 2 (1.4%) patients, and no dislocation occurred during follow-up. Primary THA was performed in 70 patients. The mean operation time was 108min. The mean intraoperative blood loss was 406g. The rate of short rotator muscle preservation was 65.7%. No IOFs were observed, and 2 (2.9%) patients developed dislocation during follow-up. Both patients with dislocations reported a history of rheumatoid arthritis, and dislocations were attributed to falls. Female sex (odds ratio [OR] 5.73, 95% confidence interval [CI] 1.26-26.0, p<0.05) and greater distance between the lesser trochanter and the ischium (OR 1.14, 95%CI 1.04-1.25, p<0.01) were associated with short rotator muscle preservation.
Conclusion: In all of the HAs and forty-six (65.7%) THAs, the piriformis and conjoint tendons were preserved. SA-HA would lead to lower rate of IOFs and postoperative dislocations.
