# Leg length and offset in short-stem total hip arthroplasty: is a single offset-implant sufficient to restore the hip rotation centre within a range of 5 mm?

## TL;DR

This study shows that using two different implant offsets in short-stem hip surgery improves accuracy in restoring leg length and hip position compared to a single offset.

## Contribution

The study demonstrates that dual-offset implants significantly improve anatomical reconstruction accuracy in short-stem total hip arthroplasty.

## Key findings

- A single 130° offset implant achieved satisfactory restoration in 55.7% of cases.
- A dual-offset system improved accuracy to 79.1%, showing a statistically significant advantage.

## Abstract

Short-stem total hip arthroplasty (THA) has gained popularity due to its bone-preserving properties and improved physiological load transmission to the proximal femur. Despite these advantages, the ability of short-stem implants to reliably restore leg length and offset remains debated. This study evaluates whether a single offset implant is sufficient for accurate anatomical reconstruction or if multiple offset options are necessary.

A total of 148 anteroposterior pelvic radiographs of patients scheduled for short-stem THA were analysed using MediCAD® software. Femoral offset and leg length were measured, and the accuracy of anatomical reconstruction was assessed within a 5-mm target range. Comparisons were made between a single offset (130°) implant and a dual-offset system (130° and 119°) using the McNemar-Bowker test.

With a single 130° CCD (Caput-collum-diaphyseal) offset implant, 55.7% (82/148) of cases achieved satisfactory leg length and offset restoration. The use of a dual-offset system improved accuracy to 79.1% (117/148), demonstrating a statistically significant advantage (p < 0.001).

The study highlights the need for at least two CCD-angle-offset combinations in short-stem THA to address anatomical variability. A dual-offset system enhances accuracy, reduces biomechanical imbalances, and therefore we expect improvements in clinical outcomes, particularly in teaching hospitals where standardization is essential.