Recovery trajectories of spatiotemporal gait after bipolar hemiarthroplasty versus closed reduction and internal fixation for unstable intertrochanteric fracture: a prospective wearable-sensor study

BACKGROUND: Geriatric hip fractures, particularly unstable intertrochanteric fractures, pose a significant global health challenge with high morbidity and mortality. The optimal surgical management remains debated, with both Closed Reduction and Internal Fixation (CRIF) and Bipolar Hemiarthroplasty (BHA) being widely accepted treatment options. However, there is a conspicuous paucity of objective, quantitative data comparing the longitudinal gait recovery trajectories following these two distinct surgical approaches. This study aimed to leverage validated wearable inertial sensors to systematically characterize and compare the spatiotemporal gait recovery patterns of elderly patients undergoing CRIF versus BHA for unstable intertrochanteric fractures. METHODS: This prospective cohort study enrolled 48 patients aged > 70 years with unstable intertrochanteric fractures (AO/OTA 31-A2/A3). Patients were allocated to Group A (CRIF with PFNA, n = 21) or Group B (BHA, n = 27) based on surgeon preference and patient factors. Baseline frailty was assessed using the modified Frailty Index (mFI) and it was comparable between 2 groups. A comprehensive battery of spatiotemporal gait parameters was objectively quantified using validated Gait Up Physilog® 5 wearable inertial sensors at 2 weeks, 1 month, 3 months, and 6 months postoperatively. RESULTS: At 3 months postoperatively, the BHA group demonstrated markedly superior gait parameters compared to the CRIF group, including significantly higher cadence (82.9 ± 27.3 vs. 51.7 ± 22.3 steps/min; p = 0.025) and shorter gait cycle time (1.6 ± 0.5 s vs. 2.7 ± 1.0 s; p = 0.028), reflecting a more confident and fluid gait pattern in the BHA cohort. However, this functional advantage attenuated by 6 months, as the CRIF group exhibited a compensatory "catch-up" phenomenon, achieving comparable gait parameters (p > 0.05) once fracture consolidation was established. No postoperative complications were observed in either group during the study period. CONCLUSIONS: While both BHA and CRIF are effective treatments for unstable intertrochanteric fractures, BHA offers a clinically meaningful advantage in early-to-mid-term gait recovery. The immediate intrinsic stability provided by arthroplasty facilitates earlier return to confident ambulation, which is of paramount importance for frail geriatric patients with limited physiological reserve. For select high-risk patients, BHA may be preferred to mitigate risks of prolonged immobility and optimize functional recovery. LEVEL OF EVIDENCE: Level III, Therapeutic Study.