# Impact of Surgeon Hand Dominance on Clinical and Functional Outcomes in Total Knee Arthroplasty: A Comparative Evaluation of Right and Left Knees

## TL;DR

This study examines whether a right-handed surgeon's hand dominance affects the outcomes of right and left knee replacements, finding no overall superiority between the two.

## Contribution

The study is the first to compare right and left knee arthroplasty outcomes based on surgeon hand dominance under standardized protocols.

## Key findings

- Right knees showed better long-term range of motion, while left knees had better early functional scores.
- No significant differences were found in radiological alignment or overall clinical outcomes between the groups.
- Left knee surgeries had longer hospital stays compared to right knee surgeries.

## Abstract

Background: Total knee arthroplasty (TKA) is a commonly performed surgical intervention for end-stage gonarthrosis and aims to restore function, reduce pain, and improve quality of life. While the impact of surgical technique and implant selection on outcomes is well established, the potential role of surgeon ergonomics and hand dominance in influencing clinical outcomes has not yet been adequately investigated. This study compares the functional, clinical, and radiological outcomes of right and left TKA procedures performed under complete standard protocols by a right-handed surgeon who always operated from the right side of the surgical table.

Methods: This retrospective single-center study evaluated 100 patients (50 right, 50 left knees) who underwent primary TKA between 2020 and 2022 at the Department of Orthopedics and Traumatology, Kastamonu Taşköprü State Hospital, Kastamonu, Türkiye. Demographic, perioperative, functional, and radiological parameters were evaluated. Functional scores (Knee Injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), Kujala, Oxford), pain levels (Visual Analog Scale (VAS)), and range of motion (ROM) were recorded preoperatively, at one month and one year. Radiological results were evaluated using hip-knee-ankle angle (HKAA), medial distal femoral angle (MDFA), and medial proximal tibial angle (MPTA) measurements. Statistical comparisons were made using appropriate parametric and nonparametric tests.

Results: Both groups showed significant postoperative improvements in ROM, pain, and functional scores (p < 0.001). The right knee group had superior ROM at one year (p = 0.047), while the left knee group showed better KOOS and Oxford scores at early follow-up (p = 0.042 and p = 0.006, respectively). No significant difference was found in radiological alignment angles (p > 0.05), indicating consistent implant positioning. Hospital stay was longer in the left knee group (p = 0.011). These results show short- and long-term differences between right and left knee prostheses, but neither demonstrates overall clinical superiority.

Conclusion: Despite minor differences, the laterality of the operated knee did not significantly differ in overall outcomes. These findings emphasize that compliance with standard surgical technique, ergonomic consistency, and patient-specific planning are more effective in achieving TKA success than the surgeon's dominant hand.