Download PDFOpen PDF in browserMeasured Resection and Gap Balancing Techniques Result in Similar Femoral Component Rotations Regardless of Preoperative Coronal Deformity: A Database Analysis of 3922 Cases5 pages•Published: March 8, 2024AbstractA common goal in total knee arthroplasty (TKA) is to obtain collateral ligament balance in both flexion and extension while maintaining neutral overall coronal alignment. Femoral component rotation is a key variable in achieving this goal. There are two prominent techniques used in TKA to determine implant orientation, measured resection and gap balancing, but there is some controversy over which technique is superior. At our institution, we regularly use both techniques over a wide range of patients with varying degrees of preoperative coronal deformity. We therefore asked, using intraoperative measurements from a surgical navigation system, can we detect significant differences in external rotation of the femoral component between measured resection and gap balancing techniques, and do any such differences occur more frequently or at higher levels at particular values of preoperative coronal deformity?We analysed 3922 navigated TKA cases undertaken at our institution which had complete measurements of preoperative overall coronal alignment and external rotation of the femoral component relative to the dorsal condyles line. We then compared cases using measured resection to those using the gap balancing technique, stratifying patients by degree of preoperative coronal deformity and applying a two-sample t-test. A total of 1969 cases that used measured resection and 1953 cases that used the gap balancing techniques were identified. We found no significant differences between the two techniques across most of the preoperative coronal deformity groupings, though small differences were detected in two specific subgroups: the femoral component was slightly more externally rotated in the measured resection cohort when the preoperative coronal deformity was between neutral and 50 valgus (mean ± standard deviation - measured resection: 3.60 ± 1.10, gap balancing: 3.00 ± 1.10, p < 0.00625) and between 50 valgus and 100 valgus (measured resection: 4.30 ± 1.40, gap balancing: 3.70 ± 1.30, p < 0.00625). This study has shown that there were essentially no substantial differences between the external rotation of the femoral component between the gap balancing and measured resection techniques regardless of the degree of preoperative coronal deformity. Overall, we feel that surgical decisions regarding which technique to use should be based more on any correlations with other patient outcome measures that may be better elucidated in future studies. Keyphrases: database study, gap balancing, measured resection, surgical navigation, total knee arthroplasty In: Joshua W Giles (editor). Proceedings of The 22nd Annual Meeting of the International Society for Computer Assisted Orthopaedic Surgery, vol 6, pages 35-39.
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