Yasuaki Tamaki, Keizo Wada, Shota Shigekiyo, Yuto Sugimine, Ken Tomonari and Koichi Sairyo : Accuracy of intraoperative leg length and stem version measurements in robotic-assisted total hip arthroplasty using the Mako system with enhanced mode., International Orthopaedics, 50, 1, 121-126, 2026.
(Summary)
This study evaluated the accuracy of intraoperative leg length and femoral anteversion measurements obtained during total hip arthroplasty (THA) using the Mako robotic system with enhanced mode.A total of 55 hips in four men and 51 women who underwent primary THA with the Mako system via an anterolateral approach were retrospectively evaluated. Intraoperative measurements of leg length and femoral anteversion displayed by the Mako enhanced mode were compared with postoperative CT-based measurements. Absolute errors and their distributions were calculated to assess the accuracy of intraoperative assessments.The mean absolute error was 2.3 ± 1.8 mm for postoperative leg length discrepancy and 2.9 ± 2.2° for stem anteversion. Of the 55 hips, 46 (83.6%) showed leg length errors within 3 mm and 51 (92.7%) within 5 mm. For stem anteversion, 48 hips (87.3%) were within 3° and all 55 hips (100%) were within 5°. Mako enhanced mode could not be completed in 10.7% of cases because of femoral array loosening or screw penetration into the medullary canal.Mako enhanced mode demonstrated clinically acceptable accuracy for intraoperative measurement of leg length and femoral anteversion, contributing to precise femoral stem implantation in robotic-assisted THA.
(Keyword)
Humans / Arthroplasty, Replacement, Hip / Female / Male / Middle Aged / Robotic Surgical Procedures / Retrospective Studies / Aged / Leg Length Inequality / Femur / Hip Prosthesis / Adult / Tomography, X-Ray Computed / Hip Joint / Intraoperative Period
Yasuaki Tamaki, Daisuke Hamada, Keizo Wada, Shota Shigekiyo, Yuto Sugimine, Yutaka Kinoshita, Koichi Tomita and Koichi Sairyo : Comparison of methods for evaluating soft tissue balance in robotic-assisted total knee arthroplasty: A cadaveric study., The Knee, 58, 2026.
(Summary)
Robotic-assisted total knee arthroplasty (TKA) can simulate postoperative soft tissue balance based on three-dimensional positional information for the prosthesis and preoperative soft tissue balance data. However, the accuracy of soft tissue balance data obtained during robotic-assisted TKA is unclear. This study aimed to compare the reproducibility of three different assessment methods for soft tissue balance in robotic-assisted TKA and to examine the influence of examiner experience.Seven fresh-frozen cadavers were used. Three examiners assessed the medial and lateral gaps by applying a continuous varus/valgus load to the knee throughout the full range of motion using an image-free system (Navio). Soft tissue balance was evaluated by applying mild manual stress (mild group), maximum manual stress (max group), and a Z-retractor (Z group). Each examiner performed the procedure twice, and intra-rater and inter-rater reliability was evaluated using the intraclass correlation coefficient (ICC).In medial gap assessment, the ICCs for intra-rater reliability ranged from 0.88 to 0.95 in the mild group, 0.89 to 0.94 in the max group, and 0.89 to 0.95 in the Z group, with respective ICCs of 0.88, 0.88, and 0.92 for inter-rater reliability. In lateral gap assessment, the ICCs for intra-rater reliability ranged from 0.37 to 0.66 in the mild group, 0.33 to 0.86 in the max group, and 0.62 to 0.96 in the Z group, with respective ICCs of 0.41, 0.24, and 0.57 for inter-rater reliability.Intra-rater and inter-rater reliability was high for the medial gap assessment but lower for the lateral gap assessment.
(Keyword)
Humans / Arthroplasty, Replacement, Knee / Robotic Surgical Procedures / Cadaver / Reproducibility of Results / Range of Motion, Articular / Knee Joint / Aged / Male / Female