# Does Robotic Total Hip Arthroplasty Technology Have Any Benefit in Achieving Equal Limb Length via the Direct Anterior Approach?

## TL;DR

This study compares robotic-assisted and conventional hip replacement surgeries to see which is better at preventing leg length differences.

## Contribution

The study evaluates the effectiveness of robotic-assisted THA in reducing leg length discrepancy via the direct anterior approach.

## Key findings

- Robotic-assisted THA resulted in significantly lower mean leg length discrepancy compared to conventional THA.
- Adjusting for age and BMI confirmed the significant reduction in leg length discrepancy with robotic assistance.
- Severe leg length discrepancies were similarly minimized in both groups.

## Abstract

Background

Leg length discrepancy (LLD) is a common and clinically significant complication following total hip arthroplasty (THA), potentially affecting functional outcomes and patient satisfaction. Robotic-assisted THA has emerged as a promising alternative to conventional techniques, offering enhanced precision in implant positioning. This study aims to evaluate whether robotic-assisted THA via the direct anterior approach provides significant advantages in achieving equal limb length compared to conventional techniques.

Methodology

A retrospective analysis was conducted among 200 patients with primary hip osteoarthritis who underwent THA via the direct anterior approach from February 2018 to August 2024. Of these, 100 patients underwent robotic-assisted THA, and 100 underwent conventional THA. Postoperative leg length measurements were obtained using standardized radiographs, and LLD was classified into mild (<5 mm), moderate (5-10 mm), and severe (>10 mm). Statistical analyses, including independent t-tests, chi-square tests, and analysis of covariance, were performed to compare LLD between the two groups while adjusting for age and body mass index (BMI).

Results

The robotic-assisted group demonstrated a significantly lower mean LLD compared to the conventional group (4.05 mm vs. 6.0 mm; p = 0.001). After adjusting for age and BMI, the difference remained significant (adjusted mean difference = -1.84 mm, 95% confidence interval = 0.638-3.03; p = 0.003). The rates of moderate-to-severe LLD were 55% in the conventional group and 44% in the robotic-assisted group, though this difference was not statistically significant (p = 0.23).

Conclusions

Robotic-assisted THA via the direct anterior approach significantly reduces the magnitude of LLD compared to conventional techniques while achieving similar efficacy in minimizing severe discrepancies. These findings highlight the potential benefits of robotic assistance in optimizing surgical precision, though further research is needed to justify its cost-effectiveness and impact on long-term functional outcomes.