# Gait Recovery After Total Hip Arthroplasty with Subtrochanteric Osteotomy in Highly Dislocated Hips: A Retrospective Single-Center Cohort Study

## TL;DR

This study examines gait recovery after hip replacement surgery in patients with highly dislocated hips, finding improvements in gait parameters up to one year post-surgery but no further progress after five years.

## Contribution

The study provides novel insights into gait recovery after total hip arthroplasty with subtrochanteric osteotomy in patients with severe hip dislocation.

## Key findings

- Improvements in terminal double support and vertical ground reaction forces were observed up to one year post-surgery.
- No further gait improvements were seen at five years post-surgery compared to one year.
- Leg length discrepancy significantly improved after surgery.

## Abstract

Background: We aimed to analyze various gait parameters before and after THA for patients with a highly dislocated hip to examine gait recovery and whether it is continued. Methods: This was a retrospective, single-center study. We enrolled 10 patients with a highly dislocated hip (10 hips) due to developmental dysplasia of the hip (DDH) or sequelae of septic arthritis of the hip (SSH). A spatio-temporal gait analysis was performed before THA with subtrochanteric osteotomy and one year after surgery for all patients, and 5 of them had a complete follow-up gait analysis at five years postoperatively. Demographics, clinical outcome, and radiological data were collected. Results: At one year postoperatively, the terminal double support (TDS) increased from 8.6% (4.3–12.6) to 11.3% (5.8–14.0) of the gait cycle (p = 0.02). The vertical ground reaction force (vGRF) increased from 0.96 N/BW (0.69–1.30) to 1.11 N/BW (0.95–1.31) for the first peak (p = 0.045) and from 0.87 N/BW (0.59–1.12) to 1.10 N/BW (1.00–1.30) for the second peak (p = 0.001). However, there was no improvement in any gait parameters at five years postoperatively compared to one year postoperatively. The mean HHS was 57.2 (43–67) before surgery and 79.6 (61–88) at the last follow-up (p = 0.001). The preoperative leg length discrepancy (LLD), which was 43.6 mm (18.2–71.6), and improved to 9.8 mm (2.1–22.1) after surgery. Conclusions: Improvements in stance-phase stability (TDS) and vertical ground reaction forces (vGRF) enhanced gait after THA in patients with highly dislocated hips; however, these gains were only observed until 1 year postoperatively, with no further improvement thereafter. Notably, the magnitude of improvement in TDS and vGRF may exceed that typically reported after THA for primary osteoarthritis.