Opening Wedge High Tibial Osteotomy Research Articles

Single-Joint Type Hybrid Assistive Limb for Knee Training in the Acute Postoperative Phase After Opening Wedge High Tibial Osteotomy: A Feasibility and Safety Trial

Single-Joint Type Hybrid Assistive Limb for Knee Training in the Acute Postoperative Phase After Opening Wedge High Tibial Osteotomy: A Feasibility and Safety Trial

[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.

Open-wedge high tibial osteotomy with and without bone void filler: Allograft leads to faster bone union and weight bearing with comparable return to work and sports rates.

To compare the clinical and radiological outcome of open-wedge high tibial osteotomy (OWHTO) with allogenous bone chips to a control group without bone void filler. The focus was on the rates and timelines of return to work (RTW) and return to sports (RTS), given the significance of these factors for the satisfaction of young and active patients. One hundred and ninety-five cases of OWHTO (112 cases with allograft vs. 83 cases without graft) with a follow-up of 17 ± 4.8 months were included in this retrospective analysis. Various metrics were investigated, including time to return to full weight bearing, RTW and RTS rates and timelines, International Knee Documentation Committee (IKDC) Score, Cincinnati-Sportsmedicine and Orthopaedic Centre Scoreand Tegner Score. The time to bone union was determined on radiographs taken at 6, 16, 28 and 53 weeks. Patients returned to full weight bearing after 8.8 ± 4.8 weeks. RTW was possible for 92.8% after 13.7 ± 12.3 weeks. 96.2% returned to sports after 22.7 ± 8.3 weeks, but the number of disciplines and workouts per week diminished (p < 0.001, p = 0.006). A shift to low-impact and recreational sports was observed. Patients with allograft filling had earlier bone union (21 ± 12.3 vs. 31.9 ± 14.2 weeks, p < 0.001) and returned faster to full weight bearing (8.2 ± 4.5 vs. 9.8 ± 5 weeks, p = 0.013). There was no difference between groups in the IKDC Score (69 ± 17.2 vs. 69.9 ± 15.2, p = 0.834), Cincinnati-Sportsmedicine and Orthopaedic Centre Score (68 ± 18.3 vs. 69.4 ± 18.2, p = 0.698) and Tegner Score (3.8 ± 1.5 vs. 4 ± 1.5, p = 0.246). Allograft filling leads to faster bone union and return to full weight bearing but showed no significant advantage in terms of RTW/RTS, overall patient satisfaction and functional scores. The decision for or against filling the osteotomy gap, therefore, remainsa case-by-case decision. Level III, Retrospective cohort study.

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.

Better clinical outcomes and return to sport rates with additional medial meniscus root tear repair in high tibial osteotomy for medial compartmental knee osteoarthritis.

This retrospective study aimed to investigate whether the repair of medial meniscus posterior root tears (MMPRTs) is effective for improving clinical outcomes and return to sports rates in young patients (50 years old or younger) with medial compartment knee osteoarthritis (KOA) and MMPRTs. Between 2016 and 2019, 153 patients with KOA and MMPRTs who underwent open-wedge high tibial osteotomy (OWHTO) were retrospectively included. The patients were divided into OWHTO combined with MMPRT repair (n = 73) and isolated OWHTO (n = 80) groups. Lysholm scores, Hospital for Special Surgery (HHS) scores, Tegner scores, flexion contracture, range of knee flexion, return to sports rates and postoperative complications were compared. Radiological outcomes, including hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), joint line convergence angle (JLCA) and Kellgren-Lawrence (K-L) grade, were compared between the two groups. After a mean follow-up of 30.1 ± 3.0 months, the OWHTO + Repair group observed better clinical outcomes compared with the OWHTO group (Lysholm score: 86.7 ± 7.4 vs. 81.6 ± 6.9, p = 0.023. HHS score: 85.4 ± 8.20 vs. 80.5 ± 7.1, p = 0.039). The OWHTO + Repair group had higher Tegner scores and return to sports rates than the OWHTO group (Tegner score: 6 vs. 5, p = 0.020; return to sports rates: 38% vs. 15%, p = 0.001). No fracture or major complications occurred. Radiological outcomes showed no significant differences between the two groups (HKA: 181.1 ± 2.7 vs. 180.1 ± 1.5 n.s; MPTA: 90.1 ± 1.8 vs. 89.2 ± 1.4, n.s; JLCA:1.9 ± 0.7 vs. 2.1 ± 0.7, n.s). Additional MMPRT repair during OWHTO was associated with better clinical outcomes and higher rates of return to sports in young patients with medial compartment KOA and MMPRTs. Level III.

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).

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.

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.

Hybrid Closed Wedge High Tibial Osteotomy Maintains the Leg Length After Surgery Compared With Open Wedge High Tibial Osteotomy.

This study aimed to assess the changes in leg length following open wedge high tibial osteotomy (OWHTO) and hybrid closed wedge high tibial osteotomy (h-CWHTO) and whether the change in leg length was associated with preoperative radiographic factors and the change in planned opening or closing width. We retrospectively evaluated the data of patients who underwent OWHTO (n=57) and h-CWHTO (n=31) between 2016 and 2019. Standing full-length anteroposterior radiographs were obtained preoperatively and one year postoperatively. Changes in the lower leg and tibial length were measured using radiography, and the planned opening or closing width was decided via operative planning. Flexion contracture was examined preoperatively and one year postoperatively using a goniometer, and the correlation factors and changes in leg length were analyzed using Spearman's rank correlation. In the OWHTO group, the lower leg was significantly longer by a mean of 6.0±8.7 mm compared to that preoperatively (p<0.01); however, no significant difference was observed in the h-CWHTO group (mean, -0.56±11.6 mm) (p=0.788). In the OWHTO group, flexion contracture did not improve after surgery, however, in the h-CWHTO group, flexion contracture significantly improved from -7.1±7.0 degrees to -4.7±6.2 degrees postoperatively (p<0.01). No radiographic factors or bone opening or closing width were associated with changes in leg length in both groups. OWHTO led to a significant elongation of the lower leg while leg length was maintained post-h-CWHTO. However, the changes in leg length following both OWHTO and h-CWHTO were not predictable from preoperative radiographic factors or changes in bone width.

Femoral trochlear groove cartilage damage after open-wedge high tibial osteotomy is associated with the change in patellar height relative to the femoral condyle

BackgroundMedial open-wedge high tibial osteotomy (OWHTO) is performed for isolated medial compartment osteoarthritis or osteonecrosis of the knee and correction of varus deformity of the full lower extremity. OWHTO may induce sagittal parameter changes, including these in the tibial posterior slope (TPS), patellar height (PH), and patellofemoral joint problems. This study aimed to identify radiographic parameters associated with patellofemoral cartilage damage after OWHTO. HypothesisThe patellofemoral joint cartilage worsens after OWHTO and is adversely affected by PH changes. Patients and methodsTwenty patients (25 knees) who underwent primary OWHTO and subsequent implant removal surgery, including second-look arthroscopy for evaluation of the patellofemoral cartilage condition were enrolled. The patients were received 12 to 35 months of postoperative follow-up, and categorized into two groups according to whether patellofemoral cartilage damage worsened. TPS and PH parameters, including the Insall–Salvati, Blackburne–Peel, Caton–Deschamps, and modified Blumensaat (MBI) indices, were measured on lateral knee radiographs. The hip-knee-ankle and medial proximal tibial angles were measured using an anteroposterior radiograph of the full lower extremity. The extent of change from preoperative to postoperative (Δ) was calculated for all indices. ResultsEleven knees (44%) had worsening cartilage conditions in the femoral trochlear groove, with>1-degree of deterioration in the International Cartilage Repair Society grade. The radiographic measure for predicting patellofemoral cartilage deterioration was ΔMBI (95% confidence interval [CI]: 3.53×10–14–0.812, p=0.047). PF cartilage damage tended to progress in ΔMBI<–0.145. The postoperative TPS and HKAA in patients with deterioration in patellofemoral cartilage damage was greater than that in patients without deterioration in patellofemoral cartilage damage (p=0.037 and 0.038, respectively). DiscussionThe patellofemoral cartilage damage tends to progress after OWHTO. ΔMBI is a factor for predicting worsening patellofemoral cartilage condition. However, attention should be paid to the excessive posterior slope as high TPS and valgus alignment as valgus HKAA because intraoperative control of MBI is impossible. Level of evidenceIV, retrospective study.

Three-Dimensional Hinge Axis Orientation Contributes to Simultaneous Alignment Correction in All Three Anatomical Planes in Opening-Wedge High Tibial Osteotomy

To investigate the simultaneous effect of 3-dimensional (3D) hinge axis (HA) orientation on alignment parameters in all 3 anatomical planes in high tibial osteotomy. A computed tomography-based 3D model of a human tibia/fibula was used to establish a 3D tibial coordinate system based on the tibial mechanical axis. In here, an HA was positioned and an opening-wedge high tibial osteotomy with a rotation angle of 10° over the HA was simulated. HA rotation in the axial plane ranged from 0° to 90° and HA tilt relative to the axial plane ranged from -20° to+20°. The study quantified the simultaneous effect of HA orientation on change of alignment parameters in all anatomical reference planes. HA rotation within the tibial axial plane between orientations perpendicular to the coronal and sagittal planes primarily affected both coronal and sagittal plane alignment, with an inverse relationship between these planes (range: 0°-9.7°); the effect of HA rotation on the change in axial plane alignment was maximally 0.9°. In contrast, HA tilt relative to the tibial axial plane primarily affected axial alignment (maximum change: 6.9°); the effect on change in both coronal and sagittal plane alignment was maximally 0.6°. HA rotation in the tibial axial plane primarily affects sagittal and coronal plane alignment, and HA tilt relative to the tibial axial plane primarily affects axial plane alignment. Integrating 3D HA orientation in malalignment planning and correction offers the potential to minimize unintended corrections in nontargeted planes in uniplanar correction osteotomies and to facilitate intentional multiplanar correction with a single osteotomy.

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.

The 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. The 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. Three 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. The 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). Small 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. Incorporating 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.

Medial Meniscus Posterior Root Reconstruction and Open-Wedge High-Tibial Osteotomy for Medial Meniscus Posterior Root Tear With Varus Knee Alignment: A Retrospective Study on Short-Term Outcomes.

We describe13 cases of medial meniscus posterior root tear (MMPRT) with varus knee alignment treated with medial meniscus posterior root reconstruction (MMPR-R) and open-wedge high-tibial osteotomy (OWHTO) to identify an optimal MMPRT treatment. We retrospectively reviewed 13 patients (mean age: 66.3 ± 8.0 years) who underwent MMPR-R and OWHTO. The Knee Injury and Osteoarthritis Outcome Score (KOOS), femorotibial angle (FTA), percentage mechanical axis(%MA) on radiography, and medial meniscus extrusion (MME) on magnetic resonance imaging (MRI) between the preoperative period and last follow-up were compared. Moreover, meniscus healing status and the International Cartilage Repair Society (ICRS) classification of the medial femoral condyle and medial tibial plateau on arthroscopy between the initial surgery and second-look arthroscopy were compared. The mean follow-up duration was 12.8 ± 2.2 months. At the last follow-up, the KOOS significantly improved (P < 0.01). Based on the FTA and %MA, the varus alignment was predominantly corrected at the last follow-up (P < 0.01). The MME was increased in nine (62.9%) patients, and the mean MME significantly increased at the last follow-up (P = 0.04). Second-look arthroscopy revealed improvements in the ICRS grade for the medial femoral condyle and medial tibial plateau in six (46.2%) patients. However, the results did not significantly differ. Regarding meniscus healing, four (30.8%) patients presented with complete healing, eight (57.1%) with partial healing, and one (7.7%) with failed healing. The MMPRT with varus knee alignment significantly improved with MMPR-R and OWHTO. However, the MME and meniscus healing were unsatisfactory.

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.

A new technique of autologous bone grafting for open-wedge high tibial osteotomy.

This study aimed to demonstrate the application of orthotopic bone flap transplantation with a fibula transplantation (OBFT-FT) in open-wedge high tibial osteotomy (OW-HTO) and to assess the effect of OBFT-FT on gap healing. From January to July 2020, 18 patients who underwent OW-HTO with OBFT-FT were reviewed for this study. Demographics, postoperative complications, and radiological and clinical outcomes of patients were collected. Finally, the clinical outcomes of patients were analyzed. A total of 14 patients were included in this study. The average age and body mass index were 59.6 ± 9.2 years and 28.1 ± 4.5 kg/m2, respectively. The average correction angle and gap width were 9.5 ± 1.8° and 10.2 ± 2.7 mm, respectively. The rates of radiological gap healing at sixth week, third month, and sixth month were 42.9%, 85.7%, and 100%, respectively. The mean Lysholm score, International Knee Documentation Committee score, and visual analog scale scores at sixth-month follow-up were significantly better than the preoperative scores (p < 0.001, p < 0.001, p = 0.001, respectively). And, no delayed union or non-union, collapse, loss of correction, or surgical site infection were found. As a new technique for autologous bone graft, the OBFT-FT could be successfully applied in the treatment of gap healing after OW-HTO, and excellent radiological and clinical outcomes could be seen on patients' short-term follow-up.

The use of medial joint opening rather than mechanical axis deviation to determine the clinical outcomes after high tibial osteotomy.

The aim of this study was to evaluate whether achieving medial joint opening, as measured by the change in the joint line convergence angle (∆JLCA), is a better predictor of clinical outcomes after high tibial osteotomy (HTO) compared with the mechanical axis deviation, and to find individualized targets for the redistribution of load that reflect bony alignment, joint laxity, and surgical technique. This retrospective study analyzed 121 knees in 101 patients. Patient-reported outcome measures (PROMs) were collected preoperatively and one year postoperatively, and were analyzed according to the surgical technique (opening or closing wedge), postoperative mechanical axis deviation (deviations above and below 10% from the target), and achievement of medial joint opening (∆JLCA > 1°). Radiological parameters, including JLCA, mechanical axis deviation, and the difference in JLCA between preoperative standing and supine radiographs (JLCAPD), an indicator of medial soft-tissue laxity, were measured. Cut-off points for parameters related to achieving medial joint opening were calculated from receiver operating characteristic (ROC) curves. Patients in whom the medial joint opening was achieved had significantly better postoperative PROMs compared with those without medial opening (all p < 0.05). Patients who were outliers with deviation of > 10% from the target mechanical axis deviation had significantly similar PROMs compared with patients with an acceptable axis deviation (all p > 0.05). Medial joint opening was affected by postoperative mechanical axis deviation and JLCAPD. The influence of JLCAPD on postoperative axis deviation was more pronounced in a closing wedge than in an opening wedge HTO. Medial joint opening rather than the mechanical axis deviation determined the clinical outcome in patients who underwent HTO. The JLCAPD identified the optimal postoperative axis deviation necessary to achieve medial joint opening. For patients with increased laxity, lowering the target axis deviation is recommended to achieve medial joint opening. The target axis deviation should also differ according to the technique of undergoing HTO.