Medial Open-wedge High Tibial Osteotomy Research Articles

Evaluation of the efficacy of medial open wedge high tibial osteotomy combined with anterior cruciate ligament reconstruction in the treatment of varus knee osteoarthritis with anterior cruciate ligament injury

Objective: To evaluate the efficacy of medial open wedge high tibial osteotomy (MOWHTO) combined with anterior cruciate ligament (ACL) reconstruction in the treatment of varus knee osteoarthritis (OA) with ACL injury. Methods: A follow-up study. The study retrospectively analyzed the patients underwent MOWHTO combined with ACL reconstruction for treatment of varus knee OA with ACL injury in Tianjin Hospital between April 2018 and September 2022. The preoperative and postoperative posterior slope angle (PSA), hip-knee-ankle angle (HKA), visual analog scale (VAS) pain scores, Lysholm score, International Knee Documentation Committee (IKDC) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and Tegner score were compared. The follow-up indicators were recorded at 6 weeks, 3 months and 1 year after operation, and the complications were recorded. Results: The study included 32 patients (23 males, 9 females) with a mean age of (50.7±8.4) years. The mean follow-up time was (21.2±4.8) months. PSA increased from 9.2°±1.8° preoperatively to 11.1°±2.4° postoperatively, and HKA increased from 168.7°±2.2° to 181.5°±2.2° (both P<0.01). The indicators such as VAS score (6.8±1.1 vs 1.8±0.4), Lysholm score (52.6±7.1 vs 82.0±6.4), IKDC score (64.7±6.2 vs 80.3±10.0), WOMAC score (51.8±6.3 vs 81.8±6.5), and Tegner score (1.9±0.6 vs 5.0±1.0) were all improved after the operation (all P<0.01). Complications occurred in 5 patients (15.6%), including hematomas, sensory abnormalities, intermuscular vein thrombosis and correction angle loss. Conclusion: MOWHTO combined with ACL reconstruction is a safe and effective approach for the treatment of varus knee OA with ACL injury.

Factors to improve odds of success following medial opening-wedge high tibial osteotomy: a machine learning analysis

BackgroundAlthough high tibial osteotomy (HTO) is an established treatment option for medial compartment osteoarthritis, predictive factors for HTO treatment success remain unclear. This study aimed to identify informative variables associated with HTO treatment success and to develop and internally validate machine learning algorithms to predict which patients will achieve HTO treatment success for medial compartmental osteoarthritis.MethodsThis study retrospectively reviewed patients who underwent medial opening-wedge HTO (MOWHTO) at our center between March 2010 and December 2015. The primary outcomes were a lack of conversion to total knee arthroplasty (TKA) and achievement of a minimal clinically important difference of improvement in the Knee Injury and Osteoarthritis Outcome Score (KOOS) at a minimum of five years postoperatively. Recursive feature selection was used to identify the combination of variables from an initial pool of 25 features that optimized model performance. Five machine learning algorithms (XGBoost, multilayer perception, support vector machine, elastic-net penalized logistic regression, and random forest) were trained using five-fold cross-validation three times and applied to an independent test set of patients. The performance of the model was evaluated by the area under the receiver operating characteristic curve (AUC).ResultsA total of 231 patients were included, and 200 patients (86.6%) achieved treatment success at the mean of 9 years of follow-up. A combination of seven variables optimized algorithm performance, and the following specific cutoffs increased the likelihood of MOWHTO treatment success: body mass index (BMI) ≤ 26.8 kg/m2, preoperative KOOS for pain ≤ 46.0, preoperative KOOS for quality of life ≤ 33.0, preoperative International Knee Documentation Committee score ≤ 42.0, preoperative Short-Form 36 questionnaire (SF-36) score > 42.25, three-month postoperative hip-knee-ankle angle > 1.0°, and three-month postoperative medial proximal tibial angle (MPTA) > 91.5° and ≤ 94.7°. The random forest model demonstrated the best performance (F1 score: 0.93; AUC: 0.81) and was transformed into an online application as an educational tool to demonstrate the capabilities of machine learning.ConclusionsThe random forest machine learning algorithm best predicted MOWHTO treatment success. Patients with a lower BMI, poor clinical status, slight valgus overcorrection, and postoperative MPTA < 94.7 more frequently achieved a greater likelihood of treatment success.Level of evidenceLevel III, retrospective cohort study.

Effect of Meniscal Tear Patterns and Preoperative Cartilage Status on Joint Space Width After Medial Opening-Wedge High Tibial Osteotomy

Background: Medial opening-wedge high tibial osteotomy (MOWHTO) is performed to treat young adults with medial compartment knee osteoarthritis associated with varus deformity. However, factors influencing joint space width (JSW) vary according to the type of medial meniscal tear and have not yet been completely elucidated. Purpose: To examine changes in JSW according to the type of medial meniscal tear after MOWHTO and analyze the influencing factors. Study Design: Cohort study; Level of evidence, 3. Methods: This study was conducted on 134 patients who underwent MOWHTO for medial osteoarthritis and were followed up for >2 years. The patients were classified into 3 groups based on medial meniscal status: intact, nonroot tear, and root tear. The authors then measured the JSW preoperatively and at 3 months, 6 months, 1 year, and >2 years postoperatively; analyzed whether the change in JSW varied according to meniscal status; and determined the association of these changes with the preoperative cartilage grade of the medial femoral condyle (MFC) and medial tibial plateau (MTP). International Knee Documentation Committee (IKDC) scores were used to evaluate clinical function. Results: Of the 134 patients, the medial meniscus was intact in 29 patients, a nonroot tear was observed in 58 patients, and a root tear was observed in 47 patients. Postoperatively, JSW increased for all groups, but the timing of the increase varied between the groups (P < .001). JSW increased the most 6 months postoperatively in the intact group and 3 months postoperatively in the nonroot tear and root tear groups (P < .001). Additionally, the increase in JSW was the greatest in the root tear group. Preoperatively, MFC and MTP cartilage status differed among the groups; MTP status did not affect the JSW, but MFC status did (P < .001). The IKDC score increased from the preoperative to postoperative time point in all groups, but there was no significant difference between groups. Conclusion: The authors observed that the amount and timing of increase in JSW were dependent on the pattern of medial meniscal tear observed when MOWHTO was performed. In addition, the cartilage grade of MFC before surgery was associated with changes in JSW. The IKDC score was not significantly different between groups. However, a longer follow-up period is needed to analyze the correlation with the meniscal tear pattern and JSW.

Faster Bone Gap Union in Medial Opening Wedge High Tibial Osteotomy With 3D-Printed Synthetic Bioresorbable Polycaprolactone and Tricalcium Phosphate Osteotomy Gap Fillers Compared to Allogeneic Osteotomy Gap Fillers: A Retrospective Matched-Pair Cohort Study.

The use of synthetic bone substitute material (BSM) as osteotomy gap fillers have been reported to improve outcomes in medial opening wedge high tibial osteotomy (MOWHTO). This study aims to evaluate the early radiological outcomes (bone union) and complication rates of the novel patient-specific 3D-printed honeycomb-structured polycaprolactone and tricalcium phosphate (PCL-TCP) synthetic graft compared to allogeneic bone grafts as an osteotomy gap filler in MOWHTO. A retrospective matched-pair analysis of patients who underwent MOWHTO with either PCL-TCP synthetic graft or allogenic femoral head allograft as osteotomy gap filler was performed. The osteotomy gap was split into equal zones (Zone 1-5), and bone union was evaluated on anteroposterior radiographs based on the van Hemert classification at 1, 3, 6, and 12 months postoperatively. Postoperative complications including infection, lateral hinge fractures, and persistent pain was measured. The study and control group were matched for age, smoking status, diabetes mellitus, and osteotomy gap size. Significantly greater bone union progression was observed in the PCL-TCP group than in the allograft group at 1 month (Zones 1-3), 3 months (Zones 1-4), 6 months (Zones 1-2, 4), and 12 months (Zones 2-3, 5) postoperatively (P < 0.05). No significant difference in complications rates was noted between the two groups at 1 year. Bone union rates observed in patients who underwent MOWHTO with the PCL-TCP synthetic graft osteotomy gap filler were superior to those in the allograft group at 1 year postoperatively, with no significant difference in complication rates (postoperative infection, lateral hinge fractures, and persistent pain).

Factors Causing Unintended Sagittal and Axial Alignment Changes in High Tibial Osteotomy: Comparative 3-Dimensional Analysis of Simulation and Actual Surgery

Background: Unintended secondary changes in the posterior tibial slope (PTS) and tibial torsion angle (TTA) may occur after medial open-wedge high tibial osteotomy (MOWHTO). In surgical procedures using patient-specific instruments (PSIs), it is essential to reproduce the PTS and TTA that were planned in simulations. Purpose: To analyze the factors causing unintended sagittal and axial alignment changes after MOWHTO. Study Design: Case series; Level of evidence, 4. Methods: Overall, 63 patients (70 knees) who underwent MOWHTO using a PSI between June 2020 and June 2023 were retrospectively reviewed. Preoperative and postoperative computed tomography scans were 3-dimensionally reconstructed. Simulated osteotomy was performed so that the weightbearing line could pass through the target point. A PSI gapper was 3-dimensionally printed to fit the posteromedial corner of the osteotomy gap in the simulated HTO model. After MOWHTO using the PSI gapper, the actual postoperative model was compared with the preoperative or simulation model. This assessment included PTS, TTA, hinge axis, and osteotomy-related parameters. Cortical breakage around the lateral hinge was evaluated to assess stability. Results: The mean PTS and TTA did not change in the simulation. However, significant changes were observed in the actual postoperative PTS and TTA (change, –2.4°± 2.2° and −3.9°± 4.7°, respectively). The PTS was reduced, while the TTA decreased with internal rotation of the distal fragment. The difference in the axial hinge axis angle (AHA) between the simulation and actual surgery was the factor most correlated with the difference in the PTS (r = 0.625; P < .001). In regression analysis, the difference in the AHA was the only factor associated with the difference in the PTS (β = 0.558; P = .001), and there were no factors that showed any significant associations with the difference in the TTA. In subgroup analyses for the change in the TTA, the correction angle and anterior osteotomy angle were significantly higher in the more internal rotation group (P = .023 and P = .010, respectively). The TTA change was significantly higher in the unstable group with lateral cortical breakage (P = .018). The unstable group was more likely to show an internal rotation of ≥5° (odds ratio, 5.0; P = .007). Conclusion: The AHA was associated with a difference in the PTS between the simulation and actual surgery. The change in the TTA was caused by a combination of multiple factors, such as a large correction angle and anterior osteotomy angle, but mainly by instability of the lateral cortical hinge.

Changes in Patellar Height and Tibial Posterior Slope after Biplanar High Tibial Osteotomy with Computer-Designed Personalized Surgical Guides: A Retrospective Study.

Medial opening-wedge high tibial osteotomy (MOWHTO) is a surgical procedure to treat medial compartment osteoarthritis in the knee with varus deformity. However, factors such as patellar height (PH) and the sagittal plane's posterior tibial slope angle (PTSA) are potentially overlooked. This study investigated the impact of alignment correction angle guided by computer-designed personalized surgical guide plate (PSGP) in MOWHTO on PH and PTSA, offering insights for enhancing surgical techniques. This retrospective study included patients who underwent 3D-printed PSGP-assisted MOWHTO at our institution from March to September 2022. The paired t-tests assessed differences in all preoperative and postoperative measurement parameters. Multivariate linear regression analysis examined correlations between PTSA, CDI (Caton-Deschamps Index), and the alignment correction magnitude. Receiver operating characteristic (ROC) curve analysis determined the threshold of the correction angle, calculating sensitivity, specificity, and area under the curve. A total of 107 patients were included in our study. The CDI changed from a preoperative mean of 0.97 ± 0.13 (range 0.70-1.34) to a postoperative mean of 0.82 ± 0.13 (range 0.55-1.20). PTSA changed from a preoperative mean of 8.54 ± 2.67 (range 2.19-17.55) to a postoperative mean of 10.54 ± 3.05 (range 4.48-18.05). The t-test revealed statistically significant changes in both values (p < 0.05). A significant alteration in patellar height occurred when the correction angle exceeded 9.39°. Moreover, this paper illustrates a negative correlation between CDI change and the correction angle and preoperative PTSA. Holding other factors constant, each 1-degree increase in the correction angle led to a 0.017 decrease in postoperative CDI, and each 1-degree increase in preoperative PTSA resulted in a 0.008 decrease in postoperative CDI. PTSA change was positively correlated only with the correction angle; for each 1-degree increase in the opening angle, postoperative PTS increased by 0.188, with other factors constant. This study highlights the effectiveness and precision of PSGP-assisted MOWHTO, focusing on the impact of alignment correction on PH and PTSA. These findings support the optimization of PSGP technology, which offers simpler, faster, and safer surgeries with less radiation and bleeding than traditional methods. However, PSGP's one-time use design and the learning curve required for its application are limitations, suggesting areas for further research.

The influence of the weight-bearing state on three-dimensional (3D) planning in lower extremity realignment – analysis of novel vs. state-of-the-art planning approaches

BackgroundThe use of 3D planning to guide corrective osteotomies of the lower extremity is increasing in clinical practice. The use of computer-tomography (CT) data acquired in supine position neglects the weight-bearing (WB) state and the gold standard in 3D planning involves the manual adaption of the surgical plan after considering the WB state in long-leg radiographs (LLR). However, this process is subjective and dependent on the surgeons experience. A more standardized and automated method could reduce variability and decrease costs.PurposeThe aim of the study was (1) to compare three different three-dimensional (3D) planning modalities for medial open-wedge high tibial osteotomy (MOWHTO) and (2) to describe the current practice of adapting NWB CT data after considering the WB state in LLR. The purpose of this study is to validate a new, standardized approach to include the WB state into the 3D planning and to compare this method against the current gold standard of 3D planning. Our hypothesis is that the correction is comparable to the gold standard, but shows less variability due compared to the more subjective hybrid approach.MethodsThree surgical planning modalities were retrospectively analyzed in 43 legs scheduled for MOWHTO between 2015 and 2019. The planning modalities included: (1) 3D hybrid (3D non-weight-bearing (NWB) CT models after manual adaption of the opening angle considering the WB state in LLR, (2) 3D NWB (3D NWB CT models) and (3) 3D WB (2D/3D registration of 3D NWB CT models onto LLR to simulate the WB state). The pre- and postoperative hip-knee-ankle angle (HKA) and the planned opening angle (°) were assessed and differences among modalities reported. The relationship between the reported differences and BMI, preoperative HKA (LLR), medial meniscus extrusion, Outerbridge osteoarthritis grade and joint line convergence angle (JLCA) was analyzed.ResultsThe mean (std) planned opening angle of 3D hybrid did not differ between 3D hybrid and 3D WB (0.4 ± 2.1°) (n.s.) but was higher in 3D hybrid compared to 3D NWB (1.1° ± 1.1°) (p = 0.039). 3D WB demonstrated increased preoperative varus deformity compared to 3D NWB: 6.7 ± 3.8° vs. 5.6 ± 2.7° (p = 0.029). Patients with an increased varus deformity in 3D WB compared to 3D NWB (> 2 °) demonstrated more extensive varus alignment in LLR (p = 0.009) and a higher JLCA (p = 0.013).ConclusionSmall intermodal differences between the current practice of the reported 3D hybrid planning modality and a 3D WB approach using a 2D/3D registration algorithm were reported. In contrast, neglecting the WB state underestimates preoperative varus deformity and results in a smaller planned opening angle. This leads to potential under correction in MOWHTO, especially in patients with extensive varus deformities or JLCA.Clinical RelevanceIncorporating the WB state in 3D planning modalities has the potential to increase accuracy and lead to a more consistent and reliable planning in MOWHTO. The inclusion of the WB state in automatized surgical planning algorithms has the potential to reduce costs and time in the future.

Relationship between increased knee joint line obliquity after medial open-wedge high tibial osteotomy and patient-reported outcome measures.

This study evaluated the correlation between postoperative knee joint line obliquity after medial open-wedge high tibial osteotomy and patient-reported outcome measures excluding excessively overcorrected knees. This study further identified preoperative radiological factors related to the increased postoperative knee joint line obliquity. We retrospectively evaluated patients who underwent medial open-wedge high tibial osteotomy between March 2013 and March 2021. Postoperative excessively overcorrected knees with hip-knee-ankle angle > 7° were excluded. We investigated radiological parameters and patient-reported outcome measures preoperatively and at the last follow-up. The following radiologic parameters were measured: hip-knee-ankle angle, weight-bearing line ratio, mechanical medial proximal tibial angle, mechanical lateral distal femoral angle, lateral distal tibial angle, joint line convergent angle, knee joint line obliquity, ankle joint line obliquity, hip abduction angle, tibial posterior slope, Carton-Deschamps index, and patella tilting angle. Clinical outcomes were evaluated using Japanese knee outcome measures. This assessment criterion is based on the Western Ontario McMaster Universities Arthritis Index and MOS Short Form 36. Multiple regression analysis was performed to evaluate the association between postoperative knee joint line obliquity and patient-reported outcome measures or preoperative radiological factors (P < .05). A total of 52 knees were included. The mean age at the time of the surgery was 61.6 ± 9.0years and the mean follow-up period was 30.6 ± 10.1months. Increased postoperative knee joint line obliquity was associated with lower Japanese knee outcome measures. The preoperative hip-knee-ankle angle was significantly associated with postoperative knee joint line obliquity. Increased knee joint line obliquity after medial open-wedge high tibial osteotomy is associated with inferior clinical outcomes. Care should be given to the center of the rotational angulation in around-knee osteotomy to avoid postoperative increased knee joint line obliquity. Retrospective comparative study, Level III.

The tipping point in medial opening wedge high tibial osteotomy relates to the shape of the proximal tibia more than to lower limb alignment correction.

The tipping point (TP) of the knee joint isthe centre of rotation of the joint in the coronal plane. This study aimed to define the TP in medial opening wedge high tibial osteotomy (MOWHTO). Data from 154 consecutive patients with varus knee malalignment, who underwent MOWHTO between 2017 and 2021, was retrospectively reviewed. The degree of preoperative osteoarthritis (OA), using the Kellgren-Lawrence (KL) grading system,was recorded. Long-leg standing radiographs were used to record the alignment parameters, including the hip-knee-ankle angle (HKA), the mechanical lateral distal femoral angle (mLDFA), the medial proximal tibial angle (MPTA), the joint line convergence angle (JLCA) and the joint line obliquity (JLO) angle. Postoperative Tegner activity scores, Western Ontario and McMaster University Scoresand patients'satisfaction were recorded. To define the TP, the relationship of all variables to Δ JLCA (absolute difference between preoperative to postoperative JLCA values) was analysed. Linear regression was employed for Δ JLCA to preoperative JLCA and postoperative and Δ MPTA (absolute difference between preoperative and postoperative values). K-means clustering was used to partition observations into clusters, in which each observation belongs to the cluster with the nearest mean serving as a prototype of the cluster, and analysed if there was any specific threshold influencing Δ JLCA. After defining the TP, further subanalysis of the TP based on the preoperative KL OA grade and analysis of variance of this TP to the KL OA grade was performed. A total of 154 patients (77.9% males and 22.1% females) were included. The mean age was 48.2 ± 11 years, and the mean body mass index was 27.1 ± 4 kg/m2. Preoperatively, 26 (16.9%) patients had KL grade IV OA. The mean preoperative and postoperative JLCA and the significance of their relation to Δ JLCA were 2.6° ± 1.8° (p < 0.0001) and 1.9° ± 1.8° (p = 0.6), respectively. The mean Δ JLCA was 1.4° ± 1.5°. The mean pre- and postoperative MPTA and the significance of their relation to Δ JLCA were 84.6 ± 2.2 (p = 0.005) and 91.8 ± 2.5 (p < 0.0007), respectively. The mean Δ MPTA was 7.2 ± 2.3 (p = 0.3). The mean preoperative and postoperative HKA and the significance of their relation to Δ JLCA were 174.6 ± 2.5 (p = 0.2) and 181.9 ± 2.4 (p = 0.7), respectively. The overall linear regression for Δ JLCA was statistically significant for preoperative JLCA (R2 = 0.3, p < 0.0001) and postoperative MPTA (R2 = 0.09, p = 0.0001) and statistically insignificant for Δ MPTA (R2 = 0.01, p = 0.2)and postoperative HKA (R2 = 0.04, p = 0.7). MPTA > 91.5° was the optimal threshold dividing this series data set between substantial and nonsignificant Δ JLCA. In this study, the main predictive factors for intra-articular correction (Δ JLCA) after MOWHTO were the preoperative value of JLCA and the postoperative value of MPTA. A value of 92° for postoperative MPTA is potentially the optimal threshold to predict intra-articular correction. Level IV, retrospective cohort study.

Knee Joint Line Obliquity With Adaptational Hip and Ankle Joint Orientation After Medial Open Wedge High Tibial Osteotomy

Background: Time-dependent postoperative changes in knee joint line obliquity (KJLO) and subsequent adaptational changes in the hip and ankle joints have not been fully proven after medial open wedge high tibial osteotomy (MOWHTO). Purpose: To investigate the serial postoperative changes in KJLO and subsequent adaptational changes in the hip and ankle joints over time after MOWHTO. Study design: Case series, Level of evidence, 4. Methods: A total of 92 patients who underwent MOWHTO between April 2015 and December 2020 were evaluated. Radiographic parameters, including KJLO, ankle joint line obliquity (ALO), hip abduction angle (HAA), joint line convergence angle, weightbearing line ratio, and hip-knee-ankle angle, were analyzed in time sequence (preoperatively and 3, 6, 12, and 24 months postoperatively). Repeated-measures analysis of variance and post hoc analysis were used to demonstrate alterations and the statistical significance of KJLO and other related radiographic parameters over time. Results: The mean KJLO values were –1.9°, –2.1°, –2.7°, and –3.2° at 3, 6, 12, and 24 months postoperatively, respectively, indicating that there was consistent increase in valgus tilting of KJLO from 6 to 24 months (P < .001 for both 6-12 months and 12-24 months). ALO and HAA showed significant changes from 6 to 12 months (ALO, P < .001; HAA, P = .002), but not between 12 and 24 months (ALO: –3.0°, –2.7°, –1.9°, and −1.6°; HAA: –0.8°, –0.9°, –1.5°, and −1.8° at 3, 6, 12, and 24 months, respectively). The mean joint line convergence angle, weightbearing line ratio, and hip-knee-ankle angle did not change significantly from 3 months to 24 months postoperatively. Conclusion: There was a consistent increase in valgus tilting of the postoperative KJLO from 6 to 24 months after MOWHTO. The adaptive ALO and HAA significantly changed between 6 and 12 months and were maintained until 24 months after MOWHTO. It is necessary to consider the adaptive change when hip or ankle surgery is planned within this period.

Topical Use of Low-dose Tranexamic Acid Has no Effect on Drainage Volume after Medial Open Wedge High Tibial Osteotomy: A Case Control Study.

Many studies reported that tranexamic acid (TXA) was effective in reducing surgical blood loss in the perioperative period of medial open wedge high tibial osteotomy (MOWHTO). However, few studies focused on the simple topical use of TXA in MOWHTO, and the modality and dosage of topical use of TXA varied. The purpose of this study was to observe the effect of topical use of low-dose TXA on drainage volume after MOWHTO, and to analyze the related influencing factors. Data of patients who underwent MOWHTO combined with arthroscopic knee surgery in our department from January 2019 to September 2021 were retrospectively analyzed. A total of 105 patients (38 males and 67 females, aged 57.7 ± 7.5 years) were included in this study who received topical TXA or no TXA. The patients were divided into three groups: control group (39 cases), 0.5 g TXA group (40 cases), 1 g TXA group (26 cases). Postoperative drainage volume, wound healing, incidence of hematoma and deep venous thrombosis (DVT) were observed and analyzed in the three groups. The effects of gender, hypertension and diabetes on postoperative drainage volume were analyzed using a t-test. The correlation between age, body mass index (BMI), osteotomy gap and postoperative drainage volume were analyzed using the Pearson correlation coefficient. The average postoperative drainage volume of the control group was 259.54 ± 226.33 mL, that of the 0.5 g TXA group was 277.18 ± 177.68 mL, and that of the 1 g TXA group was 229.15 ± 219.93 mL. There was no statistically significant difference in postoperative drainage volume among the three groups (F = 0.423, p = 0.656). There was no local hematoma and wound infection in the three groups. The wound fat liquefaction was found in one patient of the control group. The incidence of DVT was 38.9% (7/18) and 57.1% (8/14) in the control group and 0.5 TXA group, respectively. There was no significant difference in the incidence of DVT between the above two groups (p = 0.476). The average postoperative drainage volume of male patients in the three groups was higher than that of female patients, and the differences were statistically significant (p < 0.05). There was no correlation between age, BMI, osteotomy gap and postoperative drainage volume in the three groups (p > 0.05). Topical use of low-dose TXA has no significant effect on drainage volume after MOWHTO. The drainage volume after MOWHTO in male patients was more than that in female patients. Topical administration of low-dose TXA does not increase postoperative complications, such as DVT and hematoma.

Use of Tibial Cortical Autograft for the Osteotomy Site in Medial Opening-Wedge High Tibial Osteotomy.

Medial opening-wedge high tibial osteotomy (OWHTO) is a useful treatment option in patients with medial compartment osteoarthritis. Typically, the osteotomy site is filled with material such as autologous bone graft, allograft, or synthetic bone substitute. However, all these options have disadvantages. The purpose of this study was to describe tibial cortical autograft as an alternative to conventional graft options. It was hypothesized that the tibial rectangular cortical bone that is removed from the proximal medial cortical surface of the distal tibial fragment longitudinally could be a reliable option for recovery of the gap in the osteotomy area. Cohort study; Level of evidence, 3. A total of 520 patients with medial compartment osteoarthritis who underwent OWHTO between June 2009 and March 2019 were retrospectively analyzed. Patients were divided into 3 groups according to the graft material used to fill the osteotomy site: allograft in group A, iliac crest autograft in group B, and tibial autograft in group C. Bone union, evaluated by radiographs performed at 2 weeks, 4 weeks, 2 months, 3 months, 6 months, and 1 year postoperatively, was defined as occurring when at least 50% of the gap site was bridged with callus. Clinical assessment was performed using the International Knee Documentation Committee (IKDC) and Lysholm scores. Included were 122 patients: 40 patients in group A, 42 patients in group B, and 40 patients in group C. The mean correction was 13.87°± 3.58° in group A, 12.33°± 3.92° in group B, and 14.10°± 2.99° in group C. The mean time for radiological bone union was 6.95 ± 1.40 months in group A, 4.48 ± 1.02 months in group B, and 5.07 ± 1.70 months in group C. Patients in all groups had similar IKDC and Lysholm scores at the final follow-up. This is the first report of this specific procedure in the literature. All clinical and radiological findings showed that use of tibial cortical autograft was an efficient method in patients undergoing OWHTO.

Clinical and radiological results of high tibial of osteotomy over the age of 65 are comparable to that of under 55 at minimum 2-year follow-up: a propensity score matched analysis

PurposeThe results of medial open-wedge high tibial osteotomy (MOWHTO) according to age is inconclusive. This study aimed to compare the clinical outcomes and failure of MOWHTO in patients < 55 years and > 65 years.MethodsConsecutive patients who underwent MOWHTO from July 2009 to August 2020 were retrospectively analyzed. 205 patients were considered for analysis. A 1-to-1 propensity score matched analysis to assess clinical outcomes scores including International Knee Documentation Committee (IKDC) subjective score and Lysholm score, radiologic outcomes, complication, and Total Knee Arthroplasty (TKA) conversion between patients > 65 years and patients < 55 years was performed. Radiologic outcomes included Hip-Knee-Ankle (HKA) angle, Weight Bearing Line ratio (WBLR), posterior tibial slope (PTS), and Insall-Salvati (IS) ratio before and after surgery.ResultsThe follow-up period was 50.4 months in patients > 65 years and 55.3 months in patients < 55 years. There was no significant difference in the preoperative and postoperative HKA angle, WBLR, PTS, IS ratio, IKDC score and Lysholm score between the two groups. The arthroscopic evaluation of cartilage did not show any statistically significant differences between the two groups. Regarding Minimal clinically important differences (MCID), in the 26% of the older group exceeded MCID of IKDC score; 45% of the older group exceeded MCID of Lysholm score. In the younger group, 24% exceeded MCID of IKDC score and 35% exceeded MCID of Lysholm score. In older group, there were 7 (11.3%) cases of TKA conversion while no TKA conversion was recorded in the younger group. (P = 0.007) The average time to TKA conversion was 67 months. (42 months to 90 months) Kaplan–Meier analysis revealed that the survival rate was 95.2% at 4 years in the older group.ConclusionSimilar clinical results were obtained in patients over 65 years of age that were eligible for MOWHTO at minimum 2-year follow-up as in patients under 55 years of age. MOWHTO may be a viable option in older patients if proper indications are met. However, the risk of TKA conversion must be considered preoperatively and discussed with patients.Study Design: Cohort study; Level of evidence, 3.

Higher conversion rate to knee arthroplasty in female patients following medial open-wedge high tibial osteotomy.

Most studies about medial open-wedge high tibial osteotomy (HTO) reported outcomes without focusing on gender differences. Therefore, the study compared the long-term survival rate and postoperative subjective knee function after HTO in female versus male patients with symptomatic medial compartment knee osteoarthritis. The data of three cohorts with long-term outcomes were analysed (n = 245; 32% females; age: 49 ± 7 years; Kellgren Lawrence Grade I 6.1%, II 32.7%, III 42.4%; IV 18.8%). The minimum follow-up was at least 6 years or an earlier conversion to total knee arthroplasty (TKA). The gender-specific survival rate after HTO was calculated after 5 and 10 years and compared using Kaplan-Meier analysis and the logrank test. Baseline characteristics and subjective knee function (International Knee Documentation Committee [IKDC]/Lysholm) were analysed between both genders. Forty of 78 (51.3%) women and 41 of 167 men (24.5%) underwent TKA. HTO survival in females was significantly lower (p = 0.0010). The 5- and 10-year survival rates were 85.9% and 62.6% for females and 93.4% and 77.7% for males. In females and males, from preoperative to the last follow-up, the IKDC (43 ± 15 to 58 ± 17; 47 ± 14 to 67 ± 18) and the Lysholm (42 ± 18 to 72 ± 18; 55 ± 22 to 77 ± 23) improved significantly (all p < 0.0001). Females had significantly lower preoperative and postoperative IKDC (p = 0.0438; p = 0.0035) and Lysholm scores (p = 0.0002; p = 0.0323). But the absolute improvements of the IKDC and Lysholm were not significantly different between genders. Females had higher conversion rates to TKA and lower knee function at the last follow-up. However, preoperative knee function was lower in females and the absolute improvement following HTO was similar for both genders. In general, females benefit from HTO to treat medial knee arthritis, and TKA could be postponed for half of female patients for more than 10 years. However, surgeons must be aware of the described inferior outcomes in females for realistic patient expectation management. Level II.

High survivorship and low complication rate in a single-centre series of 651 medial opening wedge high tibial osteotomy cases with a mean follow-up of 13 years.

This study aimed to report the early to midterm results of medial opening wedge high tibial osteotomy (MOWHTO) from the largest single-centre osteotomy database. The primary outcomes were reporting the radiological corrections and the functional outcomes represented by multiple patient-reported outcome measures (PROMs). The secondary outcomes were to report the complications, revisionsand survivorship up to 10 years postoperatively. A prospectively maintained single-centre database of 1138 knee osteotomies was retrospectively reviewed. Patients who underwent MOWHTO and met the inclusion criteria were included. Those inclusion criteria were moderate to severe knee pain that failed conservative management;varus knee malalignment; and isolated medial osteoarthritis of the knee. A total of 651 cases, with a mean age of 46.7 ± 9 years and a mean body mass indexof 29.6 ± 5.2 kg/m2 , were included. This comprised 71% males (n = 462) and 29% females (n = 189). The mean follow-up was 158.1 ± 45.4 months. Multiple PROMs were recorded preoperatively and serially postoperatively. This included the Knee injury andOsteoarthritisOutcome Scores, the Oxford Knee Score, the Oxford Knee Score-Activity and Participation Questionnaire, the Western Ontario and McMaster University Scores, the Visual Analogue Scale for health and pain, and the EQ-5D, which is a standardised measure of health-related quality of life. All lower limb alignment measurements were recorded pre- and postoperatively. The rates of osteotomy revision, conversion to arthroplasty, complications, and 5- and 10-year survivorship were recorded. A total of 651 cases were followed up to a mean of 158.1 ± 45.4 months. The mean planned correction angle was 7.6° ± 2.9°. The mean planned opening wedge distance was 8.1 ± 3.1 mm. The mean intraoperative anterior and posterior osteotomy gaps opening were 7.7 ± 3.4and 8.9 ± 3.8 mm, respectively. Postoperatively, the mean mechanical tibiofemoral angle improved from -5.7° ± 2.9° varus to 1.3° ± 2.5° valgus, the mean medial proximal tibial angle improved from preoperative 85.5° ± 2.3° to postoperative 91.6° ± 2.7°and the mean Mikulicz point improved from 21.7 ± 12.6% to 54.8 ± 11% (all p values < 0.001). All PROMs significantly improved at 24 months follow-up (all p values < 0.001). The rate of osteotomy revision was 1.1% at a mean of 2 ± 2.5 years postoperatively. The overall rate of arthroplasty conversion was 9.1%. This comprised 5.8% total knee arthroplasty conversion at a mean of 6.9 ± 3.5 years postoperatively and 3.2% unicompartmental knee arthroplasty conversion at a mean of 5.7 ± 2.5 years postoperatively. An overall 10.3% complication rate was recorded. The 5 and 10-year survivorship was 97.2%and 91.9%, respectively. MOWHTOis a radiologically and clinically rewarding procedure with a high survival rate at 5 and 10 years and a low complication rate in experienced hands. MOWHTO should be considered in patients presenting with medial unicompartmental knee pain with an evidence of overload and a varus mechanical coronal plane axis. Level IV, retrospective cohort study.

Cartilage regeneration is related to superior mid-term patient-reported outcomes after open-wedge high tibial osteotomy.

Medial open-wedge high tibial osteotomy (OWHTO) is related to cartilage improvement in the medial compartment. This study aimed to evaluate factors associated with cartilage improvement and patient-reported outcomes (PRO) after OWHTO. It was hypothesised that cartilage improvement is associated with favourable PRO. This retrospective study included 94 patients who underwent OWHTO. The mean follow-up period was 5 years. The weight-bearing line ratio (WBLR) was defined as the ratio of the distance from the medial tibial edge to the tibial insertion of the weight-bearing line and the tibial width. The International Cartilage Research Society grade evaluated the medial femoral condyle (MFC) and medial tibial plateau (MTP) at initial and second-look arthroscopy, and cartilage improvement after OWHTO was assessed. Postoperative knee injury and osteoarthritis outcome scores (KOOS) were compared between the groups with improved and non-improved cartilage. Additionally, factors related to cartilage improvement and postoperative KOOS scores were analysed. Regarding the MFC, KOOS pain, symptoms, activities of daily living (ADL)and quality of life (QOL) were significantly higher in the cartilage-improved group than in the non-improved group (p = 0.012, 0.003, 0.001, 0.006), and cartilage improvement was significantly related to KOOS pain, ADLand QOL (p = 0.021, 0.039, 0.013). In addition, the postoperative WBLR was associated with cartilage improvement, with a cutoff value of 54.0% (p = 0.046). Regarding the MTP, KOOS ADLand QOL (p = 0.026, 0.022) were significantly higher in the cartilage-improved group than in the nonimproved group. Body mass index (BMI) was significantly related to the postoperative QOL (p = 0.018) and associated with cartilage improvement, with a cutoff value of 25.9 kg/m2 (p = 0.002). A postoperative WBLR greater than 54.0% and a preoperative BMI below 25.9 kg/m2 were associated with cartilage improvement, positively impacting PRO after OWHTO. Level III, retrospective comparative study.

No clinical outcome difference between varus phenotypes after medial opening-wedge high tibial osteotomy at 2 years follow-up.

Clinical studies regarding medial open-wedge high tibial osteotomy (MOWHTO) often analyse a large group of mechanical varus knees rather than differentiating for its primary varus-inducing component. This study aims to compare the radiological and clinical outcomes of the most prevalent varus malalignment phenotypes using the coronal plane alignment of the knee (CPAK) classification. MOWHTO cases with minimal 2-year clinical follow-up were retrospectively selected from a knee osteotomy database (2016-2020). Based on the medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA), subjects were allocated to the correct CPAK phenotype pre- and postoperatively. Clinical outcomes were the numeric rating scale (NRS), the knee injury and osteoarthritis outcome score (KOOS) and the therapeutic response rate (TRR) at 2-year follow-up. Inter-observer correlation coefficient (ICC) and unpaired student t test were performed for cross-phenotype comparison. One hundred thirty-five (135) subjects were found eligible (53.0 years old ±9.6 [19-77], 72% male, 53% left-sided). The most prevalent preoperative phenotype was CPAK 1 (n = 70 (52%)) and the postoperative phenotype was CPAK 6 (n = 66 (49%)). All CPAK phenotypes improved significantly relative to baseline but cross-phenotype comparison yielded no significant differences in clinical outcome. The TRR at 2 years was 67% for CPAK 1, 69% for CPAK 2and 87% for CPAK 4. The TRR for CPAK 6 was 64% compared with 80% for CPAK 9, which was not significantly different. At 2-yearfollow-up, no clinically significant differences are observed between different CPAK phenotypes. Accurate MOWHTO corrections provide significant clinical improvement even in the femoral-driven varus knee and the constitutional varus knee dominated by intra-articular wear. The clinical indication for MOWHTO performance should not be reduced to the medial arthritic varus knee with underlying tibial varus alone. Level IV, retrospective comparative study.

Pre-operative Planning of High Tibial Osteotomy With ChatGPT: Are We There Yet?

ChatGPT (Chat Generative Pre-trained Transformer), developed by OpenAI (San Francisco, CA, USA), has gained attention in the medical field. It has the potential to enhance and simplify tasks, such as preoperative planning in orthopedic surgery. We aimed to test ChatGPT's accuracy in measuring the angle of correction for high tibial osteotomy for cases planned and performed at a tertiary teaching hospital in Singapore. Peri-operative angular parameters from 114 consecutive patients who underwent medial opening wedge high tibial osteotomy (MOWHTO) were used to query ChatGPT 3.0. First ChatGPT 3.0 was queried on what information it required to plan a MOWHTO. Based on its response, pre-operative medial proximal tibial angle (MPTA) and joint line congruence angle (JLCA) were provided. ChatGPT 3.0 then responded with its recommended angle of correction. This was compared against the manually planned surgical correction by our fellowship-trained surgeon. A root mean square analysis was then performed to compare ChatGPT 3.0 and manual planning. The root mean square error (RMSE) of ChatGPT 3.0 in predicting correction angle in MWHTO was 2.96, suggesting a very poor model fit. Although ChatGPT 3.0 represents a significant breakthrough in large language models with extensive capabilities, it is not currently optimized to effectively perform complex pre-operative planning in orthopedic surgery, specifically in the context of MOWHTO. Further refinement and consideration of specific factors are necessary to enhance its accuracy and suitability for such applications.

Validation of a Three-Dimensional Weight-Bearing Measurement Protocol for Medial Open-Wedge High Tibial Osteotomy.

Three-dimensional (3D) deformity assessment and leg realignment planning is emerging. The aim of this study was to (1) validate a novel 3D planning modality that incorporates the weight-bearing (WB) state (3D WB) by comparing it to existing modalities (3D non-weight-bearing (NWB), 2D WB) and (2) evaluate the influence of the modality (2D vs. 3D) and the WB condition on the measurements. Three different planning and deformity measurement protocols were analyzed in 19 legs that underwent medial open-wedge high tibial osteotomy (HTO): (1) a 3D WB protocol, after 2D/3D registration of 3D CT models onto the long-leg radiograph (LLR) (3D WB), (2) a 3D NWB protocol based on the 3D surface models obtained in the supine position (3D NWB), and (3) a 2D WB protocol based on the LLR (2D WB). The hip-knee-ankle angle (HKA), joint line convergence angle (JLCA), and the achieved surgical correction were measured for each modality and patient. All the measurement protocols demonstrated excellent intermodal agreement for the achieved surgical correction, with an ICC of 0.90 (95% CI: 0.76-0.96)) (p < 0.001). Surgical correction had a higher mean absolute difference compared to the 3D opening angle (OA) when measured with the WB protocols (3D WB: 2.7 ± 1.8°, 3D NWB: 1.9 ± 1.3°, 2D WB: 2.2 ± 1.3°), but it did not show statistical significance. The novel planning modality (3D WB) demonstrated excellent agreement when measuring the surgical correction after HTO compared to existing modalities.

Does preoperative bone marrow edema affect clinical outcomes after medial open-wedge high tibial osteotomy?

PurposeThe aim of this study is to evaluate the results of high tibial osteotomy (HTO) in patients with bone marrow edema (BME) and assess the effect of factors on the subsequent results.MethodsA total of 138 patients who underwent medial open-wedge HTO using locking plate were included in this study. BME was observed in 108 patients using preoperative magnetic resonance imaging. Clinical results were evaluated before HTO and postoperatively at 12 months. Moreover, we evaluated the factors affecting the clinical results.ResultsThe clinical scores were all significantly improved regardless of the presence of BME. There were no differences in improvement of clinical scores between patients with BME and without BME. Patients with BME showed higher postoperative Western Ontario and McMaster Universities Arthritis Index (WOMAC) stiffness scores than patients without BME. Furthermore, patients with BME on both the femur and tibia showed lower Knee Society function scores than patients with BME on either the femur or the tibia. Patients with large BME lesions exhibited a lower Hospital for Special Surgery score and WOMAC pain scores, postoperatively. In patients with BME, patients with undercorrection showed significantly lower improvement in WOMAC pain scores compared with patients with acceptable correction.ConclusionsThe clinical improvement after HTO in patients with varus and medial osteoarthritis was not different regardless of the presence or absence of BME. However, accurate alignment should be considered essential for achieving better clinical outcomes in patients with preoperative BME.