Trajectory of urinary incontinence symptoms following total hip arthroplasty for hip osteoarthritis.

INTRODUCTION: Urinary incontinence (UI), a prevalent quality-of-life-limiting condition, frequently coexists with hip osteoarthritis, potentially through pelvic floor dysfunction related to obturator internus muscle involvement. Several reports suggest improvement after total hip arthroplasty (THA), although postoperative time-course changes remain unclear. This study aimed to clarify the temporal trends in UI after THA and examine association of postoperative UI trajectories with functional recovery.

MATERIALS AND METHODS: This retrospective study included 118 female patients who underwent THA for hip osteoarthritis between October 2021 and March 2024. UI, assessed using the International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF), was defined as ICIQ-SF ≥ 1 preoperatively and at 3, 6, 9, and 12 months postoperatively, and classified as stress (SUI), urge (UUI), or mixed (MUI). Hip-related patient-reported outcomes were evaluated using the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ). Associations with BMI, age, surgical approach (direct lateral/Bauer vs. modified Watson-Jones/OCM), and UI type were tested using Mann-Whitney U, chi-squared, and repeated-measures ANOVA tests.

RESULTS: Of 118 patients (mean age at surgery, 67 years; mean BMI, 24.3 kg/m2) preoperatively, 73 (61.9%) reported UI (mean ICIQ-SF 7.88), including SUI (n = 20), UUI (n = 26), and MUI (n = 27), with a higher baseline severity in MUI than in UUI. The mean ICIQ-SF improved markedly by 3 months (3.88) with a significant time effect (p < 0.001, η2 = 0.39), but then plateaued through 12 months. Although most patients improved, 45/73 (61.6%) had persistent UI at 12 months. These patients had higher preoperative ICIQ-SF and significantly worse postoperative JHEQ (notably pain) across multiple time points, while BMI, approach, and UI type showed no significant group differences.

CONCLUSION: UI symptoms improved significantly within the first 3 months following THA; however, subsequent recovery was limited. Persistent UI was associated with poorer functional recovery and higher pain levels.