Effect of surgical approach to hip arthroplasty on postoperative pain and mobilization and on efficacy of intrathecal oxytocin for pain

ObjectiveCompare the effect of posterior surgical approach (PA) vs direct anterior approach (DAA) on speed of recovery from pain and dysfunction and on intrathecal oxytocin analgesia after total hip arthroplasty (THA). Study designNested cohort within a randomized, controlled, double-blind trial SettingHospital SubjectsIndividuals aged 31 to 80 years undergoing total hip arthroplasty (THA) MethodsIn this secondary analysis of a randomized controlled trial, the association between surgical approach and number of daily steps was assessed, and whether this was modified by receipt of intrathecal oxytocin. Data were collected from accelerometers and daily patient diaries in the first eight weeks postoperatively. Outcomes were analyzed using generalized linear regression models. ResultsNinety patients underwent THA, of which 35 (38.9%) received a PA. Patients were predominantly female (57.8%) with a mean age of 60.6 (standard deviation [SD] 9.3) years. On postoperative day one patients who received a PA with placebo took more steps (mean difference [MD] 53.72, 95% CI: -1717.86, 1825.31) than patients who underwent a DAA. Trajectories were significantly modified by whether they received oxytocin, in which patients who underwent PA with oxytocin took more steps than patients who underwent DAA (p<0.001). DiscussionFurther studies are needed to understand mechanisms underlying oxytocins interaction with surgical approach and guide considerations for recovery after THA.