Risk factors for delayed gait recovery after primary total hip arthroplasty in patients with crowe type I/II developmental dysplasia of the hip.

backgroundThe gait recovery process after total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH) is complex. However, systematic evidence regarding risk factors for delayed early postoperative gait recovery in patients with Crowe type I/II DDH remains limited.

methodsThis retrospective study included 283 patients with Crowe type I/II DDH who underwent primary THA at our institution between January 2020 and December 2024. The primary outcome was delayed clinical gait recovery at 3 months after surgery, defined as persistent limping or Trendelenburg gait after full weight-bearing was permitted and/or a Harris Hip Score (HHS) limp subscore < 11; this threshold indicates failure to reach the "no limp" score of 11 in the HHS limp subscore. Outcomes were independently adjudicated by two uniformly trained investigators, and inter-rater agreement was assessed using Cohen's kappa (κ). Model 1 included age, bilateral DDH status, American Society of Anesthesiologists (ASA) physical status class II/III, symptom duration, preoperative HHS, preoperative need for a walking aid, preoperative Trendelenburg sign, Crowe classification, preoperative leg length discrepancy (LLD), operative time, and intraoperative blood loss. Model 2 further included postoperative residual LLD, height of the acetabular center of rotation, cup abduction angle, and femoral offset change. The primary analysis was based on multiple imputation by chained equations (MICE; 20 imputations), with sensitivity analyses using the unilateral DDH subgroup, complete cases, alternative outcome definitions, a parsimonious model, an all-prespecified-covariate model, collinearity testing between preoperative and postoperative LLD, and LLD threshold analyses.

resultsDelayed gait recovery at 3 months occurred in 92 patients (32.5%). Multivariable analysis (Model 1) showed that a positive preoperative Trendelenburg sign (odds ratio [OR] = 2.87, 95% confidence interval [95% CI]: 1.55-5.31), Crowe type II (OR = 2.15, 95% CI: 1.18-3.91), preoperative LLD (per 1-mm increase: OR = 1.14, 95% CI: 1.03-1.26), age (per 1-year increase: OR = 1.03, 95% CI: 1.01-1.05), and symptom duration (per 1-year increase: OR = 1.03, 95% CI: 1.01-1.06) were independent risk factors for delayed gait recovery. The extended model (Model 2) showed that postoperative residual LLD was also independently associated with delayed gait recovery (per 1-mm increase: OR = 1.20, 95% CI: 1.02-1.41), whereas height of the acetabular center of rotation, cup abduction angle, and femoral offset change showed no independent associations. Sensitivity analyses restricted to unilateral DDH and complete-case analyses were consistent with the primary analysis.

conclusionsIn this predominantly female Chinese single-center cohort of patients with Crowe type I/II DDH undergoing primary THA, delayed clinical gait recovery at 3 months was not uncommon. Positive preoperative Trendelenburg sign, Crowe type II, greater preoperative LLD, older age, and longer symptom duration were independently associated with delayed early clinical gait recovery; postoperative residual LLD provided additional explanatory value in the extended model. These factors may help identify patients at higher risk of delayed early clinical gait recovery before surgery, but instrumented gait analysis was not performed in this study, and long-term three-dimensional gait-kinematic prognosis requires further validation. CLINICAL TRIAL NUMBER: Not applicable.