Small Improvements in Postoperative Outcome with Gap Balancing Technique Compared with Measured Resection in Total Knee Arthroplasty

Hagen Hommel1, 2, *, Daniel Kunze1, Peggy Hommel1, Peter Fennema3
1 KH-MOL GmBH Sonnenburger Weg 3, 16269 Wriezen, Germany
2 Medizinische Hochschule Brandenburg (MHB), Theodor Fontane, Fehrbelliner Straße 38, 16816 Neuruppin, Germany
3 AMR Advanced Medical Research GmbH, Hofenstrasse 89b, 8708 Männedorf, Switzerland

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© 2017 Hommel et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the KH-MOL GmBH, Sonnenburger Weg 3, 16269 Wriezen, Germany; Tel: +49 3345640401; Fax: +49 3345640402; E-mail:



There is ongoing debate about how to obtain correct rotational alignment in total knee arthroplasty (TKA). Two commonly used techniques are the measured resection (MR) and the gap balancing (GB) technique.


The objective of the present study was to analyze which of these two techniques confers a clinical advantage up to 10 years postoperatively.


Two hundred patients were randomized to either MR or GB. The primary outcome was the Knee Society Knee Score (KS) 10 years postoperatively. Secondary outcomes were passive range of motion, the Knee Society Function Score (FS), and the Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC), along with implant survival. We employed a two one-sided test (TOST) and linear mixed models to assess clinical outcomes.


Mean KS was 82 (95% confidence interval (CI), 80 – 83) and 77 (95% CI, 76 – 79) in the GB and MR group, respectively. The TOST test and linear mixed model both revealed statistical significance (p < 0.001). In addition, GB yielded better postoperative FS and WOMAC. However, between-group differences were consistently small. Implant survival rates at 10 years, with survival for any reason as the endpoint of interest, were 93.7% (95% CI, 86.4% and 97.1%) and 89.8% (95% CI, 81.9% - 94.4%) for the GB group and the MR group, respectively (p = 0.302).


Gap-balancing is a safe and reliable technique. KS for the two study groups at 10 years can be considered equivalent, and the small postoperative advantages may not extend beyond clinical relevance.

Keywords: Osteoarthritis, Knee, Total knee arthroplasty, Ligament balancing, Gap balancing, Measured resection, Randomized clinical trial.