Journal of orthopaedics最新文献

{"title":"Personalized alignment – the importance of inter-continental research for improving patient outcomes today and tomorrow","authors":"Heiko Graichen ,&nbsp;P. Gopinathan ,&nbsp;Michael T. Hirschmann","doi":"10.1016/j.jor.2025.08.046","DOIUrl":"10.1016/j.jor.2025.08.046","url":null,"abstract":"<div><div>Total knee arthroplasty (TKA) has become one of the most widely performed procedures for end-stage osteoarthritis, yet patient satisfaction continues to lag behind that of hip replacement. Advances in robotics and artificial intelligence have increased surgical precision, but improved accuracy alone does not guarantee better outcomes. The challenge lies in defining appropriate alignment and balancing strategies that respect each patient's unique anatomy and soft-tissue characteristics rather than relying on uniform targets. Personalized alignment has emerged as a promising concept, aiming to restore individual bony geometry and preserve native laxity patterns across all planes. However, questions remain about what constitutes “normal” versus “pathologic,” especially given anatomical and demographic differences between populations. Data derived largely from Caucasian cohorts may not be directly transferable to Asian patients, whose morphologies often differ substantially. This underscores the need for region-specific research, robust data collection, and harmonized workflows supported by advanced analytic systems. Only through global collaboration and objective evidence can reliable boundaries for personalized techniques be established. By integrating precision technology with truly individualized surgical planning, the next phase of TKA development seeks to raise functional outcomes and patient satisfaction worldwide.</div></div>","PeriodicalId":16633,"journal":{"name":"Journal of orthopaedics","volume":"71 ","pages":"Pages 29-31"},"PeriodicalIF":1.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differences between image-based and imageless robotics for total knee arthroplasty – an overview","authors":"Hannes Vermue ,&nbsp;Cécile Batailler ,&nbsp;Sébastien Lustig","doi":"10.1016/j.jor.2025.08.045","DOIUrl":"10.1016/j.jor.2025.08.045","url":null,"abstract":"<div><div>Robot-assisted total knee arthroplasty (TKA) has revolutionized implant positioning by enhancing surgical precision. However, significant differences exist between image-based and imageless robotic systems, influencing their accuracy, workflow, and potentially clinical outcomes. As such, this review aims to provide a structured comparison between image-based and imageless systems for TKA relevant to the surgeon. Image-based systems utilize preoperative imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI) to construct three-dimensional (3D) anatomical models for surgical planning and intraoperative guidance. In contrast, imageless systems rely on intraoperative anatomical landmark registration, reducing costs and radiation exposure but yielding a potential higher inaccuracy to define the joint-specific coordinate system.</div><div>This current concepts review examines key differences between these technologies, focusing on coordinate system accuracy, anatomical landmark identification, resection precision, and clinical implications. Image-based systems may demonstrate superior accuracy in defining coordinate systems, particularly for femoral and tibial rotational axes, yet involve higher costs and logistical complexity. Imageless systems offer real-time adaptability and avoid preoperative imaging but may be more susceptible to anatomical registration errors. Comparative clinical studies suggest similar coronal plane alignment error between the two approaches, though image-based systems may offer advantages in tibial slope precision. Radiation exposure is an important consideration, as it varies significantly based on imaging protocols and may warrant greater attention from surgeons, especially for patients who receive frequent CT follow-up. As well, while both system types allow for assessing patellofemoral tracking, in addition patient-specific 3D models allow to restore the native trochlea orientation. Although both systems improve implant positioning compared to conventional techniques, evidence on mid- and long-term improved clinical outcomes compared to the conventional technique is still lacking.</div></div>","PeriodicalId":16633,"journal":{"name":"Journal of orthopaedics","volume":"71 ","pages":"Pages 23-28"},"PeriodicalIF":1.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Standardised balancing goals are not able to reconstruct individual laxity-functional knee phenotypes in more than 50 % of knees","authors":"Heiko Graichen ,&nbsp;George Mihai Avram ,&nbsp;Randa Elsheikh ,&nbsp;Andreas Schuster ,&nbsp;Andrej M. Nowakowski ,&nbsp;Michael T. Hirschmann","doi":"10.1016/j.jor.2025.08.040","DOIUrl":"10.1016/j.jor.2025.08.040","url":null,"abstract":"<div><h3>Purpose</h3><div>Laxity Phenotype (LP) analysis has revealed a wide range of variability among knees, showing three phenotypes in extension and three in flexion. Based on this variability recently a Laxity-Functional Knee Phenotype (L-FKP) matrix was created. This study aimed (1) to assess how well-standardised balancing goals reproduce individual LPs, and (2) to develop a treatment algorithm to convert critical L-FKP groups into optimal ones.</div></div><div><h3>Methods</h3><div>Eighty-six knees were simulated using a validated alignment simulator to create and analyse the L-FKP matrix. Knees were classified as optimal (LP matched “all gaps equal” or lateral flexion laxity &lt;6 mm), intermediate, and critical (presence of medial laxity in extension and/or flexion). A three-step treatment algorithm was developed for optimizing L-FKP; first, by adjusting bony anatomy within defined boundaries, second by targeting soft tissue releases if correction remained &gt;1 mm, and third, by using additional constraint if option 1 and 2 were not sufficient.</div></div><div><h3>Results</h3><div>Only 37 % of knees showed optimal L-FKP patterns after restoring the patient-specific B-FKP. Another third of the knees was classified as suboptimal, which could be transferred to optimal L-FKP matrix groups with minor bone adaptions, finally reaching 70 % of optimal L-FKP patterns. Still, 30 % remained within the critical L-FKP matrix groups. The algorithm enabled the structured conversion of these cases into optimal groups.</div></div><div><h3>Conclusions</h3><div>Standardized balancing goals reconstruct optimal L-FKP groups in less than 40 % of knees, even if a personalized B-FKP workflow is applied. By minor bony modifications this amount can be increased to 70 %. A structured algorithm to restore optimal L-FKP is presented.</div></div>","PeriodicalId":16633,"journal":{"name":"Journal of orthopaedics","volume":"71 ","pages":"Pages 1-7"},"PeriodicalIF":1.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pros and cons of the coronal plane alignment of the knee (CPAK) classification in total knee arthroplasty – a narrative review","authors":"Elias Ammann ,&nbsp;Natalie Mengis ,&nbsp;George Mihai Avram ,&nbsp;Michael T. Hirschmann","doi":"10.1016/j.jor.2025.08.042","DOIUrl":"10.1016/j.jor.2025.08.042","url":null,"abstract":"<div><div>The increasing interest in modern alignment philosophies for total knee arthroplasty has highlighted the need for a more detailed coronal plane alignment classification system to assess preoperative phenotypes and investigate postoperative outcomes. Currently, the two most commonly used classification systems are the functional knee phenotypes (FKP) and the coronal plane alignment of the knee (CPAK) classification. Since its publication in 2021, the CPAK classification has been utilized globally in various knee-related investigations. This study examines the applications of the CPAK classification to date and summarizes its impact on the personalization of knee surgery. The study aims to identify the limitations of current classification systems and to stimulate future research in personalized knee surgery and knee phenotyping.</div></div>","PeriodicalId":16633,"journal":{"name":"Journal of orthopaedics","volume":"71 ","pages":"Pages 16-22"},"PeriodicalIF":1.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine Learning–Based prediction of complications and residual pain after total knee arthroplasty","authors":"Dirk Müller ,&nbsp;Amna Gillani ,&nbsp;Florian Hinterwimmer ,&nbsp;Anabel Arber ,&nbsp;Heiko Graichen ,&nbsp;Rüdiger von Eisenhart-Rothe ,&nbsp;Igor Lazic","doi":"10.1016/j.jor.2025.08.038","DOIUrl":"10.1016/j.jor.2025.08.038","url":null,"abstract":"<div><h3>Background</h3><div>Accurate risk adjustment is critical for outcome prediction and quality improvement in total knee arthroplasty (TKA). While machine learning (ML) offers promising capabilities, most models rely solely on patient demographics and comorbidities. The American Association of Hip and Knee Surgeons (AAHKS) has proposed a set of nine risk factors to enhance current models. This study aimed to evaluate these factors using a machine learning model based on eXtreme Gradient Boosting (XGBoost).</div></div><div><h3>Methods</h3><div>We retrospectively analyzed 783 patients who underwent primary TKA at a single academic center between January 2020 and December 2022. Preoperative clinical data and AAHKS-defined risk factors were used to train and evaluate an XGBoost model. The primary outcome measures were: (1) major complications requiring revision, (2) any complication (major or minor), and (3) residual pain at one year (Visual Analog Scale ≥4). Model performance was assessed using area under the curve (AUC), sensitivity, specificity, and accuracy. Feature importance was determined using SHapley Additive exPlanations (SHAP).</div></div><div><h3>Results</h3><div>The model achieved moderate predictive accuracy for major complications (AUC = 0.68) and any complication (AUC = 0.65), but performed poorly in predicting residual pain (AUC = 0.53). Among AAHKS-defined risk factors, only “smoking” and “previous open reduction and internal fixation (ORIF) of the knee” showed high predictive value. Other proposed variables, such as angular deformity &gt;15°, had limited impact.</div></div><div><h3>Conclusion</h3><div>An XGBoost-based ML model incorporating AAHKS-defined risk factors showed moderate effectiveness in predicting postoperative complications following TKA. However, the model was unable to reliably predict residual pain. These findings underscore the need for broader inclusion of joint-specific variables and imaging data in future risk adjustment frameworks to enhance personalized care in knee arthroplasty.</div></div>","PeriodicalId":16633,"journal":{"name":"Journal of orthopaedics","volume":"71 ","pages":"Pages 60-66"},"PeriodicalIF":1.5,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An acetabular component made from highly cross-linked polyethylene enriched with vitamin E: 10-year clinical results and wear rates","authors":"J.H.J. van Erp ,&nbsp;H. Erisen ,&nbsp;T.E. Snijders ,&nbsp;J.E.J. Bekkers ,&nbsp;A. de Gast","doi":"10.1016/j.jor.2025.08.021","DOIUrl":"10.1016/j.jor.2025.08.021","url":null,"abstract":"<div><h3>Background</h3><div>A common reason for total hip replacement revisions worldwide is aseptic loosening. To address this issue, a new acetabular component was developed with vitamin E incorporated into its irradiated highly cross-linker polyethylene (HXLPE). Vitamin E might be capable of reducing polyethylene wear by stabilizing free radicals in HLXPE, thus preventing oxidation and enhancing wear resistance. This study aimed to evaluate a vitamin E-enriched HXLPE acetabular component over a 10-year period to assess its impact on wear and osteolysis.</div></div><div><h3>Methods</h3><div>A total of 112 patients underwent total hip replacement with a vitamin E blended HXLPE acetabular component. Various assessments were conducted, such as pain scores, patient satisfaction, Harris Hip Score (HHS), amount of femoral head penetration, and radiological parameters.</div></div><div><h3>Results</h3><div>84 of 112 Patients (75 %) completed the 10-year follow-up. At the 10-year follow-up, patients reported high satisfaction (VAS score: 8.9) and high HHS (93.3). No revision procedure was performed due to instability, two patients underwent revision surgery due to a deep infection, and one patient required revision surgery due to a periprosthetic fracture. The survival rate for aseptic loosening was 100 %, with a 95.5 % rate to revision. The average rate of the femoral head penetration was 0.028 mm/year (SD: 0.011), including a 0.252 mm mean total head penetration (SD: 0.274). Several radiological parameter analyses had been conducted and revealed no abnormalities, equal to the 6-year follow-up.</div></div><div><h3>Conclusion</h3><div>This 10-year follow-up study demonstrated good clinical outcomes of the vitamin E enriched HXLPE acetabular cup with a low wear-rate. These findings suggest that incorporating vitamin E can potentially improve the effectiveness and durability of hip replacement procedures. However, further research comparing it to other polyethylene is required to determine potential clinical superiority.</div></div>","PeriodicalId":16633,"journal":{"name":"Journal of orthopaedics","volume":"71 ","pages":"Pages 48-53"},"PeriodicalIF":1.5,"publicationDate":"2025-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correlation between functional outcome and alterations of aHKA, PCOR, and Caton-Deschamps index following image-based robotic TKA in varus knees","authors":"Claudio Glowalla ,&nbsp;Laura Fischer ,&nbsp;Philipp Marius Stein ,&nbsp;Sophia Hasenknopf ,&nbsp;Heiko Graichen ,&nbsp;Rüdiger von Eisenhart-Rothe","doi":"10.1016/j.jor.2025.08.037","DOIUrl":"10.1016/j.jor.2025.08.037","url":null,"abstract":"<div><h3>Purpose</h3><div>This study evaluated the relationship between functional outcomes and radiographic parameter changes in coronal and sagittal planes after robotic-assisted TKA in varus knees.</div></div><div><h3>Methods</h3><div>Between May 2020 and December 2022, all patients who underwent robotic-assisted total knee arthroplasty (RaTKA) using Functional Alignment technique (Mako, Stryker) and met predefined inclusion and exclusion criteria were enrolled in this study. A total of 115 patients (mean age 69.7 years; BMI 27.9; ASA 2.1) with varus knee morphology (defined as an arithmetic hip-knee-ankle angle [aHKA] &lt; 0°) and complete datasets were included in the final analysis.</div><div>For analysis pre- and postoperative full-length weight-bearing radiographs and lateral knee views were obtained, and the Medial Proximal Tibial Angle (MPTA) and mechanical Lateral Distal Femoral Angle (mLDFA) in the coronal plane, as well as the Posterior Condylar Offset Ratio (PCOR) and Caton-Deschamps -Index in the sagittal plane were assessed. Based on the differences between pre- and postoperative values of the key parameters, patients were classified into two groups: Collective A, showing no deviation from preoperative alignment, and collective B, exhibiting a deviation in at least one parameter according to predefined thresholds.</div><div>Clinical outcome, and patient satisfaction 2 months postoperatively using validated patient-reported outcome measures (PROMs) were compared between the collectives.</div></div><div><h3>Results</h3><div>No significant differences were observed between the collectives regarding demographics and preoperative clinical parameters. 47 patients were assigned to Collective A, 68 to Collective B. Collective A showed significantly better OKS (26.2 vs. 29.9; p = 0.037∗), EQ-VAS (75.0 vs. 67.2; p = 0.014∗), EQ-5D (0.87 vs. 0.80; p = 0.005∗), and ROM (+4.7° vs. −9.2°; p = 0,007∗), whereas FJS was non-significantly higher in A (44.5 vs. 34.1; p = 0.062).</div></div><div><h3>Conclusion</h3><div>Anatomic bony restoration in the coronal and sagittal plane was associated with better early outcomes. Even single-parameter deviations may impair results, underscoring the importance of accurate reconstruction in robotic TKA.</div></div>","PeriodicalId":16633,"journal":{"name":"Journal of orthopaedics","volume":"71 ","pages":"Pages 8-15"},"PeriodicalIF":1.5,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-year experience with training courses using a TKA simulator – clinical impact and lessons learned","authors":"Heiko Graichen ,&nbsp;George Mihai Avram ,&nbsp;R. von Eisenhart-Rothe ,&nbsp;K. Giesinger ,&nbsp;Michael T. Hirschmann","doi":"10.1016/j.jor.2025.08.039","DOIUrl":"10.1016/j.jor.2025.08.039","url":null,"abstract":"<div><h3>Purpose</h3><div>Introduction of robotic systems and personalized alignment workflows have brought new challenges to Total Knee Arthroplasty (TKA) training. Simulator training is one promising option to reduce decision errors and increase efficiency. The aims of this study were (1) to analyse the effect of simulator training on quality and efficiency at different training courses using a TKA simulator, and (2) to measure the acceptance of simulator training.</div></div><div><h3>Methods</h3><div>Over the last 3 years 35 training courses were performed and 638 surgeons trained on the Knee-CAT simulator (SOS GmbH; Regensburg; Germany). Twenty basic courses and 15 advanced alignment courses were included. All exercises were analysed for decision quality of all bone cuts, soft tissue management and balancing steps as well as for alignment. Every decision within 1 mm/degree of an optimal reference bone cut was rated as green, every decision deviating more than 1 and less than 2mm/degree was rated as yellow and every decision deviating more than 2mm/degree was rated as red. A single red decision was rated as failed exercise. Efficiency was measured by measuring time for each surgical step as well as for the entire procedure. Effect of training was measured by comparing exercise outcome data at the beginning and at the end of the training. Compliance was measured as the number of exercises performed by delegates.</div></div><div><h3>Results</h3><div>Significant improvements for decision quality (51 %) and efficiency (62 %) were found. This positive effect was found in basic as well as in advanced TKA alignment courses. Only 36–51 % of delegates performed the training exercises at all, demonstrating a rather low compliance rate. However, delegates who completed at least one case, completed all cases in more than 85 %</div></div><div><h3>Conclusions</h3><div>Simulator training is a promising option for robotic and alignment training showing significant increase of decision quality and efficiency. However, a low compliance rate in the training courses has been observed. Future concepts may need to integrate additional training options such as video tutorials and virtual reality (VR) environment. However, proper trainee selection will remain crucial to achieve a higher compliance, as not every conventional TKA surgeon appears to be motivated in transitioning towards personalized robotic TKA surgery.</div></div>","PeriodicalId":16633,"journal":{"name":"Journal of orthopaedics","volume":"71 ","pages":"Pages 54-59"},"PeriodicalIF":1.5,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145269276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phenotyping the knee joint - a narrative review of current literature","authors":"Natalie Mengis ,&nbsp;Jules-Nikolaus Rippke ,&nbsp;Heiko Graichen ,&nbsp;George M. Avram ,&nbsp;Elias Ammann ,&nbsp;Randa Elsheikh ,&nbsp;Michael T. Hirschmann","doi":"10.1016/j.jor.2025.08.041","DOIUrl":"10.1016/j.jor.2025.08.041","url":null,"abstract":"<div><div>Phenotyping of the knee joint has been established as an important pre- and postoperative measure to better describe the individual knee joint in terms of alignment, laxity, morphology, and kinematics.</div><div>Therefore, this narrative review aims to provide a comprehensive analysis of the current literature on phenotyping to understand both the major benefits and the existing limitations.</div><div>This narrative review was conducted according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines.</div><div>A total of 38 studies were included. The included papers were categorized into two main groups, CPAK and functional knee phenotyping (FKP), of which the second group could be further subdivided into alignment, laxity, and morphology. The advantages and limitations were noted.</div><div>Understanding the underlying knee phenotype in OA knees is crucial for a more personalized approach in TKA. The standardized use of the current phenotype systems, whether CPAK or FKP is key. The advantage of CPAK is that it is easy to apply in daily practice, but it is of limited value because it may omit a lot of important information. FKP, on the other hand, contains many more parameters, which makes it difficult for the majority of surgeons to integrate into their routine planning. However, as the knee is defined by multiple parameters in three dimensions, it is of utmost importance to integrate as many factors as possible for an optimal alignment in TKA.</div></div>","PeriodicalId":16633,"journal":{"name":"Journal of orthopaedics","volume":"71 ","pages":"Pages 40-47"},"PeriodicalIF":1.5,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of the surgical workflow and technology change on early clinical outcomes in total knee arthroplasty","authors":"Prudhvi Tej Chinimilli ,&nbsp;Laurent D. Angibaud ,&nbsp;Amaury Jung ,&nbsp;Corey A. Jackson","doi":"10.1016/j.jor.2025.08.047","DOIUrl":"10.1016/j.jor.2025.08.047","url":null,"abstract":"<div><h3>Introduction</h3><div>Total knee arthroplasty (TKA) encompasses diverse surgical workflows that vary in bone cut sequencing and alignment strategies. This study evaluates the impact of transitioning from femur-first measured resection (MR) to tibia-first gap balancing (GB) using the same computer-assisted orthopaedic surgery system (CAOS). The clinical and technical impact of this transition was assessed across two phases of GB adoption to capture effects of surgical learning and workflow adaptation.</div></div><div><h3>Methods</h3><div>A retrospective review was conducted on 225 TKA cases performed by a single senior surgeon. Patients were grouped into three cohorts: (1) MR (75 cases), (2) GB early (first 75 GB cases), and (3) GB late (subsequent 75 GB cases). All cases used the same CAOS system and GB cases utilized a force-controlled distractor integrated into the CAOS system to acquire dynamic joint gap data for full-arc-of-motion. KOOS Jr. scores were collected preoperatively and at one-year follow-up. Intraoperative parameters including femoral and tibial alignment, tibia slope, tibial insert thickness, and planned and checked joint gaps were analyzed.</div></div><div><h3>Results</h3><div>Postoperative KOOS Jrimprovement was highest in the GB late cohort (34.1 ± 20.9), significantly greater than both MR (27.3 ± 15.8, p = 0.025) and GB early (27.7 ± 16.1, p = 0.036). MR and GB early were not significantly different (p = 0.89). Compared to MR, GB cohorts showed greater variability in femoral resection parameters, along with increased femoral flexion and tibial slope. From GB early to GB late, there was a clear refinement in technique, with GB late demonstrating significantly tighter and more consistent medial and lateral gaps.</div></div><div><h3>Conclusion</h3><div>Transitioning to a tibia-first GB workflow with a force-controlled distractor enabled more precise and individualized gap management, leading to improved clinical outcomes. While early GB clinical outcomes were comparable to MR, continued use of the GB technique was associated with refined surgical execution and superior clinical outcomes.</div></div>","PeriodicalId":16633,"journal":{"name":"Journal of orthopaedics","volume":"71 ","pages":"Pages 32-39"},"PeriodicalIF":1.5,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}