Opening Wedge High Tibial Osteotomy Research Articles

Comparison of clinical outcomes among patients treated with high tibial osteotomy and meniscal repair of degenerative medial meniscal tear with mild varus deformity.

The clinical benefits of high tibial osteotomy (HTO) in patients with mild varus deformity with degenerative medial meniscal tear (DMMT) remain unclear. This study aimed to compare clinical outcomes among middle-aged patients with mild varus deformity who underwent arthroscopic meniscal repair and HTO for DMMT. In this retrospective study, patients who underwent isolated arthroscopic meniscal repair via the inside-out technique and those who underwent medial opening-wedge HTO were assigned to group M and H, respectively. The inclusion criteria were: an age of 40-65 years; percentage of mechanical axis of 30-50% measured using full-length weight-bearing anteroposterior radiographs; Kellgren-Lawrence grade ≤ 2; minimum postoperative two-year follow-up; and HTO correction angle < 10°. Clinical outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and minimal clinically important difference achievement rate for the KOOS subscales preoperatively and at the final follow-up. Group M and H included 21 and 41 patients, respectively. The median ages were 53 and 58 years in groups M and H, respectively. In group H, 24 cases underwent meniscal repair. No significant differences in all KOOS subscales were found preoperatively. However, the median KOOS symptoms subscale in group H (89.3) was significantly better than that in group M (80.4) at the final follow-up (p = 0.04). The main finding of the study indicated that KOOS symptoms after HTO were superior to those after isolated arthroscopic meniscal repair for DMMT. HTO might be a potentially useful treatment for DMMT in middle-aged patients with mild varus deformity, even with a small correction angle. Retrospective comparative study, Level III.

Association Between Joint Line Convergence Angle and Patient-Reported Outcomes of Opening-Wedge High Tibial Osteotomy.

A larger joint line convergence angle (JLCA) increases the stress load on the medial compartment. Few reports, however, have discussed the effect of the JLCA on the cartilage status and clinical outcomes after opening-wedge high tibial osteotomy (OWHTO). To reveal the effect of the JLCA on clinical results after OWHTO. We hypothesized that a smaller JLCA improves cartilage status and clinical outcomes by reducing mechanical stress in the medial compartment. Cohort study: Level of evidence, 3. This retrospective study included 106 knees that underwent OWHTO and second-look arthroscopy during implant removal 1 year after OWHTO. The mean follow-up period was 5.5 (SD, 2.9) years. The pre- and postoperative JLCAs were measured radiographically. The International Cartilage Repair Society (ICRS) grades of the medial femoral condyle (MFC) and the medial tibial plateau (MTP) were evaluated during the initial and second-look arthroscopy. The relationship between the JLCA and cartilage status, and the Knee injury and Osteoarthritis Outcome Score (KOOS) at the final follow-up were evaluated. Preoperative JLCA was related to improvements in the ICRS grade of the MFC and the MTP, with cutoff values of 2.6° (sensitivity, 0.700; specificity, 0.561; P = .016) and 2.4° (sensitivity, 0.704; specificity, 0.595; P = .028), respectively. In addition, the preoperative JLCA was related to KOOS Pain (P = .037), Symptoms (P < .001), Activities of Daily Living (P = .005), Sports Activities (P = .005), and Quality of Life (P = .006) subscales using multivariable linear regression analysis. The postoperative JLCA was not related to the improvement in the ICRS grade of the MFC but was related to the improvement in the ICRS grade of the MTP, with a cutoff value of 1.6° (sensitivity, 0.704; specificity, 0.603; P = .015). Furthermore, postoperative JLCA was related to the KOOS Pain (P = .004), Symptoms (P = .002), Activities of Daily Living (P = .031), Sports Activities (P < .001), and Quality of Life (P = .015) subscales. A smaller pre- and postoperative JLCA was related to improvements in the ICRS grade and favorable clinical outcomes, with a mean 5.5-year follow-up after OWHTO.

Digging into the Cause of Abnormal Patellar Kinematics After Open-Wedge High Tibial Osteotomy via a Quantitative Study on In Vivo Soft Tissue Functional Changes

The biomechanical mechanism of postoperative patellofemoral joint (PFJ) complications after open-wedge high tibial osteotomy (OWHTO) has not been investigated. This study was to determine the length changes in the patellar tendon (PT), medial patellotibial ligament (MPTL), medial patellofemoral ligament (MPFL), and quadriceps moment arm (QMA) during staircase motion before and after OWHTO. Computed tomography (CT) scans of 15 patients’ lower extremities were used to reconstruct three-dimensional models, and magnetic resonance imaging (MRI) of the knee and hip joints was used to mark the soft tissue footprints. Then, such soft tissue lengths were quantified by a dual fluoroscopic imaging system (DFIS). Additionally, function scores were used to assess patient outcome changes. The results showed that there was a contraction of the PT after OWHTO due to its adhesion to the osteotomy site, causing PT length to be negatively correlated to the open-wedge angle. In addition, the shortening of the MPTL and QMA caused patellar instability and an imbalance in the strength of the lower extremities. Additionally, most knee function scores improved after OWHTO, except the Feller scores. Multiple methods should be considered to optimize surgical procedures, postoperative rehabilitation, and physical therapy.

Spacer-type tibial osteotomy versus open wedge high tibial osteotomy and unicompartmental knee arthroplasty for Kellgren-Lawrence grade 3–4 medial unicompartmental knee osteoarthritis in patients younger than 65 years

BackgroundSpacer-type tibial osteotomy have been proven a novel and effective osteotomy to treat osteoarthritis, while lack of comparison with other surgical methods in younger patients. This study aims to evaluate the short-term clinical outcomes of spacer-type tibial osteotomy versus open wedge high tibial osteotomy (OWHTO) and unicompartmental knee arthroplasty (UKA) for Kellgren-Lawrence (K-L) grade 3–4 osteoarthritis (OA) in patients younger than 65 years.MethodsThis retrospective study analyzed a total of 224 patients with K-L grade 3–4 knee OA treated from March 2018 to November 2020. Three groups were created according to the operation type. The clinical outcomes recorded preoperatively and at 6, 12 and 24 months postoperatively were the range of motion (ROM), visual analogue scale (VAS), American Knee Society Score (KSS), Western Ontario and McMaster Universities Global (WOMAC) score, operation time, length of incision, relevant complications and failures. Radiographic parameters were measured to evaluate the correction of varus deformity.ResultsThe cohort comprised 224 patients; 70 underwent spacer-type tibial osteotomy, 73 underwent OWHTO, and 81 underwent UKA. The spacer group had the shortest incision (P = 0.000), least amount of bleeding (P = 0.000), and shortest operation time (P = 0.000). UKA achieved the most significant pain relief based on VAS (P = 0.014), KSS pain score (0.030), and WOMAC score (P = 0.000) at 6 months postoperatively, but there were no differences between three groups at 12 and 24 months postoperatively. The spacer and OWHTO groups achieved significantly greater ROM changes compared with the UKA group (all P = 0.000). The complication rate did not significantly differ between the three groups. No surgical failures were identified in HTO but two spacer dislocations in spacer group and three polyethylene dislocations in UKA.ConclusionFor younger patients with K-L grade 3–4 OA, OWHTO seems to be the most appropriate method through clinical comparisons. Although spacer-type tibial osteotomy offers shorter operation time and comparable clinical outcomes, it also has extended recovery phase, additional fibular incision and the risk of spacer dislocation, which did not appear to be superior to OWHTO and UKA under the indications outlined in this study.Trial registrationRetrospectively registered, QYFY WZLL 27,021.

Prediction of the Serial Alignment Change after Opening-Wedge High Tibial Osteotomy Based on Coronal Plane Alignment of the Knee Using Machine Learning Algorithm.

Categorization of alignment into phenotypes can be useful for predicting and analyzing postoperative alignment changes after opening-wedge high tibial osteotomy (OWHTO). The purposes of this study were (1) to develop a machine learning model for the predicting the Coronal Plane Alignment of the Knee (CPAK) phenotypes of final alignment after OWHTO, and (2) to analyze predictive factors for final alignment phenotypes. Data were retrospectively collected from 163 knees that underwent OWHTO between March 2014 and December 2019. Each data was assessed at three time points: preoperatively, at 3 months postoperatively, and the final follow-up. Constitutional alignment was also evaluated. Machine learning models were developed using two independent feature sets consisting of serial radiologic parameters and CPAK phenotypes. The area under the curve (AUC) was used as a primary metric to determine the best model. To evaluate the feature importance, Shapley additive explanation (SHAP) analysis was also performed on the best model. Multi-layer perceptron (MLP) was the best prediction model, with the highest AUC of 0.867 based on radiologic parameters and 0.783 based on CPAK phenotypes. Joint line obliquity (JLO) at 3 months postoperatively was the most important factor among the radiologic parameters for predicting the final CPAK phenotypes. The features of constitutional and preoperative alignments also contributed, although the features of alignments at 3 months postoperatively were the highest contributing predictors. In conclusion, the developed machine learning models of the MLP showed excellent performance in predicting the final CPAK phenotypes after OWHTO. Postoperative JLO was the most important radiologic parameter for predicting the final alignment. The combination of features of the constitutional, preoperative, and postoperative periods enabled high accuracy and performance in predicting the final alignment. Level of evidence: Retrospective cohort study; Level III Key words: Knee, High tibial osteotomy, CPAK classification, Machine learning, Prediction.

Posteromedial opening wedge high tibial osteotomy has favourable outcomes in simultaneous medial meniscus posterior root repair and varus medial knee osteoarthritis patients without concomitant root tear

PurposeTo evaluate the radiological and clinical outcomes in two patient groups: first, varus aligned medial meniscus posterior root tear (MMPRT) patients who underwent posteromedial open wedge high tibial osteotomy (PMOWHTO) and simultaneous root repair; second, patients with varus medial knee osteoarthritis without MMPRT who underwent PMOWHTO.MethodsPatients had MMPRT repair concomitant with PMOWHTO and varus medial knee osteoarthritis without concomitant root tear patients who underwent PMOWHTO and were reviewed. Radiographic parameters, medial meniscus extrusion (MME) and Knee Society Scores [KSSs, including the following subscores: knee score (KS) and knee function score (KFS)] were evaluated. Continious variables are expressed as the median and interquartile range (IQR) [IQR: (Q1;Q3); Q1: median of lower half, Q3: median of upper half]. The minimum follow-up period was 24 months [29 (28;35) months].ResultsA total of 36 knees of 34 patients underwent PMOWHTO were included. Patients were divided into two groups according to the presence or absence of a MMPRT. Nineteen of the 36 knees had MMPRTs, and all of them had concomitant root repair (Group 1). Seventeen of the 36 patients did not have MMPRTs (Group 2). The posterior tibial slope (PTS) decreased postoperatively in a total of 36 knees (p < 0.001). There were no significant changes in MME postoperatively in any intragroup comparison. The preoperative and follow-up MMEs of Group 1 were greater than those of Group 2 (p < 0.001). The KSs and KFSs in both Group 1 and Group 2 increased during follow-up [KS; Group 1: 43 (36;53) vs. 86 (84;95), p < 0.001. Group 2: 49 (45;57) vs. 89 (80;93), p < 0.001. KFS; Group 1: 60 (50;60) vs. 90 (80;100), p < 0.001. Group 2: 60 (50;60) vs. 80 (80;90), p < 0.001]. All knees achieved minimal clinically important difference (MCID) in terms of KSs. Eighteen (95%) knees achieved MCID in Group 1, and 17 (100%) achieved MCID in Group 2 in terms of KFSs. There were no differences between Groups 1 and 2 in terms of preoperative and follow-up KSs or preoperative KFSs. The follow-up KFSs in Group 1 was significantly greater than that in Group 2 (p = 0.032).ConclusionsPMOWHTO has favourable clinical and radiological outcomes and prevents PTS increase in simultaneous MMPRT repair and varus medial knee osteoarthritis patients without concomitant root tear.Level of evidenceLevel IV, case series.

Serial Quantitative Evaluation of Load Redistribution and Osteotomy Gap After Medial Open-Wedge High Tibial Osteotomy.

The goal of medial open-wedge high tibial osteotomy (MOW-HTO) is to redistribute load by realigning the lower limb. This surgery is indicated for mild to moderate medial compartment osteoarthritis with varus deformity in cases unresponsive to conservative treatment. Procedures for accompanying cartilage lesions, such as multiple drilling on the medial femoral condyle (MFC), are often performed simultaneously, potentially affecting bone metabolism along with load redistribution and union progression. This study assessed changes in bone metabolism following MOW-HTO. Two-year follow-up data were collected from 51 knees undergoing MOW-HTO between March 2019 and December 2020. Single-photon emission computed tomography and conventional CT (SPECT/CT) were performed on postoperative Day 1, 3 months, 1 year, and 2 years. Maximum standardized uptake value (SUVmax) was measured in each compartment and the osteotomy gap. At 1 year postoperatively, SUVmax decreased in the medial femur and tibia zones (p < 0.001). SUVmax decreased in the lateral osteotomy gap zones at 1 year (p = 0.001 anterior; p = 0.002 posterior), while medial zones showed a sustained increase. At the posteromedial zone, SUVmax decreased at 2 years (p = 0.012). Subjects were divided into two groups: those with MFC drilling (group one) and those without (group two). SUVmax was higher in group one throughout the 2 years (p < 0.001). Unloading effects were notable in the medial compartment. MFC drilling increased SUVmax, creating different patterns between groups. SUVmax decrease in the osteotomy gap occurred earlier in the lateral zone.

Arthroscopic Microdrilling for Full-thickness Trochlear Cartilage Defects in Patients Undergoing High Tibial Osteotomy Confers Improved Cartilage Status at 1 year and Rate of Minimal Clinically Important Difference at Short-term Follow-up.

To compare the patient-reported outcome improvements and cartilage status of trochlear cartilage defects (TCDs) after additional arthroscopic microdrilling versus no treatment for TCDs during medial open-wedge high tibial osteotomy(MOWHTO) METHODS: Patients who underwent MOWHTO with either microdrilling (Group M) or no treatment (Group N) for near full-thickness TCDs (International Cartilage Repair Society[ICRS] grade≥3B) from March 2010 to September 2022 were retrospectively reviewed, with a minimum 2-year follow-up. 1:1 Propensity score matched-Group N was created. Comparative analyses were conducted using patient-reported outcomes(PROs) and minimal clinically important difference (MCID). Trochlear cartilage status was visually assessed via second-look arthroscopy 1 year postoperatively and categorized as deteriorated, maintained, or improved. Overall, 30 for group M and 84 patients for group N were included. The mean follow-up period of the matched groups was 32.8 and 32.0 months for groups M and N. The preoperative and postoperative radiographic parameters did not differ between the groups (Kellgren-Lawrence grade, pre- and postoperative alignment, medial proximal tibia angle). Both groups achieved significant clinical improvement in patients with medial compartment osteoarthritis and combined full-thickness TCD (p<0.001). PROs and improved PROs at final follow-up were not significantly different between groups, except for the Final Kujala anterior knee pain scale (70.4 [95% CI: 66.0-74.8] vs. 59.8 [95% CI: 53.0-67.6], p=0.018). MCID achievement rates in pain visual analogue scale (VAS), Knee injury and Osteoarthritis Outcome Scores (KOOS)-Pain, and KOOS-activity of daily living (ADL) were significantly higher in group M compared to group N (VAS, 93.3% vs. 63.3%, p=0.005; KOOS-Pain, 96.7% vs. 80.0%, p=0.044; KOOS-ADL, 86.7% vs. 63.3%, p=0.037). A significantly larger proportion of patients in group M demonstrated improvement in their TCD status compared to those in group N (93.1% vs. 44.8%, p<0.001). Arthroscopic microdrilling for near full-thickness TCD during MOWHTO improved trochlear cartilage status at 1 year but did not enhance final PROs at short-term follow-up, though it increased MCID achievement rates in some PROs (VAS, KOOS pain, KOOS ADL) compared to untreated patients. Level III, therapeutic retrospective cohort study.

Hinge Position Dominance Over Osteotomy Inclination in Medial Open-Wedge High Tibial Osteotomy: A Key Factor in Posterior Tibial Slope Changes.

A medial open-wedge high tibial osteotomy (MOWHTO) may increase the posterior tibial slope (PTS). The purpose of this study was to determine the effect of the osteotomy inclination angle (in the sagittal plane) in combination with different hinge positions (in the transverse plane) on the change in PTS due to a MOWHTO. We developed a mathematical approach to determine the effect of the osteotomy inclination angle combined with different hinge positions. The change in PTS was determined for different osteotomy inclination angles, hinge positions, and intended wedge angles. Anterior-inclined, parallel, and posterior-inclined osteotomy inclination angles were simulated. Hinge positions varied between 5° anterolateral and -45° posterolateral. The wedge angles were 5°, 10°, and 15°. Moreover, 2 in silico osteotomies were performed to verify the results of the mathematical model. The PTS was maintained when the osteotomy cut was performed parallel to the tibial plateau with a lateral hinge position. The PTS changed when the osteotomy was not aligned in the sagittal plane, ranging between 0.0° and 0.6°. Different hinge positions, however, had a large effect on postoperative PTS change, ranging between 0.1° and 10.7°. Our mathematical approach showed that the hinge position has a strong effect on the PTS. The sagittal osteotomy inclination angle had little effect on the PTS. An inclination angle parallel to the medial tibial plateau combined with a lateral hinge position does not change the PTS.

Effect of Open-Wedge High Tibial Osteotomy and Lateral Retinacular Release on the Articular Cartilage of the Patellofemoral Joint: Analysis Using Magnetic Resonance Imaging T2 Mapping.

Background/Objectives: After open-wedge high tibial osteotomy (OWHTO), the patella is displaced distally, causing patellofemoral joint degeneration. The objective of this study was to ascertain whether the combination of OWHTO and lateral retinacular release (LRR) can prevent articular cartilage degeneration of the patellofemoral joint using magnetic resonance imaging T2 mapping. Methods: This study included 37 patients (37 knees) who underwent OWHTO alone (OWHTO group) and 37 patients (37 knees) who underwent OWHTO with LRR (OWHTO + LRR group) with a correction angle of <10° for varus knee osteoarthritis. MRI was performed on all knees prior to and 6 months after surgery to assess the patellar cartilage in sagittal images for T2 mapping. Three regions of interest, (the medial facet, patellar ridge, and lateral facet), were established for the articular cartilage on the patellar side. The T2 values were subsequently quantified. Lower limb alignment, patellar height, patellar tilt angle, and lateral shift ratio were evaluated pre-and post-surgery. Results: Mean T2 values at 6 months post-surgery of the medial facet and patellar ridge of the OWHTO group showed a significant increase after surgery; no significant changes were observed in either region in the OWHTO + LRR group. In both groups, a significant decrease in patellar tilt angle was observed postoperatively; no change was noted in the lateral shift ratio or congruence angle. The change in patellar tilt angle was significantly lower in the OWHTO + LRR group than in the OWHTO group. Conclusions: LRR combined with OWHTO prevented patellofemoral joint cartilage degeneration after surgery in cases of varus knee osteoarthritis.

Medial Open-Wedge High Tibial Osteotomy with Partial Meniscectomy and Without Cyst Excision for Popliteal Cysts: A Case Series.

Introduction: Popliteal cysts (PCs) are occasionally accompanied by knee osteoarthritis (OA) and varus malalignment. However, whether concomitant arthroscopic excision of PCs with medial open-wedge high tibial osteotomy (MOWHTO) improves the osteoarthritic environment remains unclear. Therefore, this study assessed serial changes in C-size, medial meniscus extrusion (MME), and cartilage status for up to 2 years following an MOWHTO. Methods: This study retrospectively used serial magnetic resonance imaging (MRI) evaluations to assess 26 consecutive patients who underwent MOWHTO. Of the 26 patients, six with preoperative PCs were included. Based on the arthroscopic findings at the time of the MOWHTO, concomitant meniscal and chondral lesions, and whether or not partial meniscectomy was performed, were evaluated. All patients underwent second-look arthroscopy with plate removal 2 years postoperatively. The PC size, MME, and cartilage sub-scores in the medial compartment of the whole-organ MRI score (WORMS) were assessed by serial MRI preoperatively and at 3, 6, 18, and 24 months postoperatively. The recurrence of PCs and clinical outcomes, including the Rauschning-Lindgren grade, were also evaluated when serial MRI was performed. Moreover, changes in cartilage status were assessed using two-stage arthroscopy. Results: All patients underwent concomitant partial meniscectomy for medial meniscal tears in the posterior horn. A significant decrease in the mean size of preoperative PCs (27.4 ± 22.3 mm) was noted from 3 months postoperatively (8.7 ± 7.6 mm, p = 0.018), and thereafter. The mean size of PCs further decreased with time until 2 years (1.5 ± 4.0 mm, p = 0.018) following an MOWHTO with partial meniscectomy. Moreover, significant improvements in the MME and WORMS values were noted from 3 to 24 months postoperatively. Meanwhile, no PC recurrence occurred during the follow-up period and the preoperative Rauschning-Lindgren grade improved significantly with time after MOWHTO (p = 0.026). Furthermore, the two-stage arthroscopic assessments showed significant improvements in ICRS grade in the medial femoral condyle (p = 0.038). Conclusions: After an MOWHTO with partial meniscectomy, PCs decreased with time up to 2 years postoperatively; no recurrence occurred during the follow-up period, although cyst excision was not concomitantly performed. Furthermore, the reduction in PCs corresponded with improvements in MME and chondral lesions in the knee joint following the MOWHTO.

HKA angle exceeding 5 degrees is strongly associated with lateral patellar translation beyond 2 mm: surgical recommendations for avoiding adverse effects on the patellofemoral joint after OWHTO

PurposePrevious studies reported that anterior knee pain (AKP) occurs with an incidence of 32% after opening-wedge high tibial osteotomy (OWHTO). However, the biomechanical effects of this procedure on patellofemoral joints (PFJs) remain unclear. We aimed to quantify the changes in the kinematics and cartilage conditions of the PFJ during stair climbing before and after OWHTO.MethodsWe recruited 15 patients who underwent unilateral OWHTO. All patients performed continuous stair climbing under the surveillance of a dual fluoroscopic imaging system to determine accurate 6-degree-of-freedom (6-DOF) PFJs and 3D hip-knee-ankle (HKA) angles before and 6 months after OWHTO. The volume penetration centres between the patellar and femoral cartilage models were defined as contact centres. Eleven of these patients underwent quantitative T2 relaxation MRI to determine whether and how PFJ cartilage degeneration progressed.ResultsAfter OWHTO, patella valgus (mean − 3.73°, P = 0.02) and internal rotation (mean 3.14°, P = 0.03) increased compared with the preoperative conditions during the stair climbing motion. In addition, the patellae of OWTHO knees were located more laterally after surgery (1.56 ± 2.24 mm, P = 0.02) at knee flexion. Moreover, lateral shifts in the contact patterns of both the medial and lateral patellar facets together with increased T2 values (207.10 ± 21.84 ms, P = 0.04) of the lateral patella cartilage were found after surgery. Finally, the lateral patellar shift increased with decreasing varus 3D-HKA after surgery (R= -0.79, P < 0.001). Therefore, controlling 3D-HKA may be helpful in limiting lateral patellar shift.ConclusionOWHTO changed the patellofemoral kinematics and contact patterns during stair climbing, especially the lateral patellar shift, which may lead to degeneration of the PFJ cartilage. Avoiding overcorrection of the HKA angle beyond 5 degrees of valgus reduces lateral patellar translation, which may help prevent AKP. Additional clinical studies are necessary to validate these biomechanical findings and clarify their impacts on patient outcomes.

Differential effects of tibia varus deformity on clinical outcomes following high tibial osteotomy and unicompartmental knee arthroplasty for moderate medial compartment osteoarthritis with moderate varus alignment.

There is a lack of clinical evidence supporting the decision-making process between high tibial osteotomy (HTO) and unicomparmental knee arthroplasty (UKA) in gray zone indication, such as moderate medial osteoarthritis with moderate varus alignment. This study compared the outcomes between HTO and UKA in such cases and assessed the risk factor for not maintaining clinical improvements. We retrospectively reviewed 65 opening-wedge HTOs and 55 UKAs with moderate medial osteoarthritis (Kellgren-Lawrence grade ≥ 3 and Ahlback grade < 3) and moderate varus alignment (5°< Hip-Knee-Ankle angle < 10°) over 3 years follow-up. Confounding factors including patient demographics, postoperative lower limb alignment was assessed. Dummy variable was used to categorize the HTO and UKA according to presence of tibia varus deformity (medial proximal tibial angle of 85°). Clinical outcomes were measured using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score preoperatively, 1 year postoperatively, and at the last follow-up. Cox regression analysis identified risk factors for not achieving minimal clinically important differences (MCID) in WOMAC scores. The WOMAC score at 1-postoperative year significantly improved beyond MCID in all UKA and HTO. However, over a mean follow-up of 68.7 months (HTO) and 64.3 months (UKA), 16 patients (13.3%) experienced clinical deterioration. Notably, patients with suboptimal postoperative alignment, those undergoing HTO without tibial vara, and UKA with tibial vara had higher risks of clinical deterioration during the mid-term period. Tibial varus deformity differentially affects clinical outcomes after HTO and UKA in moderate medial compartment osteoarthritis with moderate varus alignment. Clinicians should consider the deformity's origin when selecting treatment for this patient, as certain combinations (HTO without tibia vara and UKA with tibia vara) are associated with increased risk of not maintaining mid-term clinical improvements.

Revisiting two thousand hinge fractures in open wedge high tibial osteotomy with a fifty years review: the oscillating saw cannot replace the traditional "ear-hand" dialogue between osteotome and hammer to estimate the elastic modulus of bone.

Hinge fracture on the lateral part of the tibia (LHF) is a common complication of medial Open Wedge High Tibial Osteotomy (OWHTO). Many factors have been described as risks for these fractures, but no study has compared an osteotome or an oscillating saw to prevent LHF following OWHTO. This "propensity-score-matched" (PSM) study was conducted from data obtained in the literature from 1974 to November 2024. A total of 10,368 knees with OWHTO were identified. After 1:1 matching based on correction amount, posterior slope change, surgeon's experience, the osteotome and oscillating groups comprised 2760 knees each. Among the 5520 knees of the PSM population, the prevalence of LHF was 6.1% in the osteotome alone group (168 cases), and 22% in the oscillating saw group (607 cases). The osteotome group had a significant lower prevalence of hinge fracture than the oscillating saw group (OR, 0.23; 95% CI, 0.19 to 0.27; p<0.0001) and a lower rate of clinically relevant hinge fractures with revision (OR, 0.34; 95% CI, 0.25 to 0.45; p<0.001. The osteotome may be an appropriate method for preventing hinge fractures following OWHTO.

Assessing the Impact of Patient-Specific Instrumentation and Fixation on Accuracy and Radiation Exposure in a Cadaveric Model of Medial Opening-Wedge High Tibial Osteotomy.

Traditional freehand techniques in high tibial osteotomy (HTO) have been shown to lack precision and accuracy. Patient-specific instrumentation (PSI) and fixation created from cross-sectional imaging have recently been introduced to address this problem. The purpose of the study was to compare traditional freehand techniques versus PSI in a human cadaveric model of HTO. It was hypothesized that the osteotomies performed using PSI would require less radiation exposure for operating room staff and would reduce deviation from the planned correction in the coronal, sagittal, and axial planes. Controlled laboratory study. Sixteen matched cadaveric knees underwent medial opening-wedge HTO via the freehand method (n = 8) or PSI technique (n = 8) with a predetermined planned opening-wedge size. Computed tomography was used to measure the achieved wedge size as well as alignment parameters in the coronal, sagittal, and axial planes. Radiation dose, number of fluoroscopic images taken, and total operative time were recorded. The mean deviation from the planned wedge size was smaller in the PSI group compared with the freehand group (0.505 vs 3.016 mm, respectively; P < .01). Total radiation dose to medical staff (0.85 vs 2.04 mGy; P < .01) and number of fluoroscopic images (15.5 vs 41; P < .01) were also smaller in the PSI versus the freehand group, respectively. No difference was seen in total operative time between the 2 groups (P = .62). In cadaveric specimens, the PSI technique demonstrated superior accuracy and decreased radiation exposure for medical staff compared with the traditional freehand technique without compromising operative efficiency. The use of PSI when HTO is performed can lead to more accurate operations and potentially improve outcomes.

Clinical outcome and complications after simultaneous bilateral medial opening-wedge high tibial osteotomy

BackgroundThe literature provides limited evidence regarding postoperative outcomes and complications following simultaneous bilateral medial opening-wedge high tibial osteotomy (MOWHTO). This study aimed to investigate the clinical outcomes and complications associated with simultaneous bilateral MOWHTO. MethodsWe retrospectively evaluated 72 knees from 36 patients (mean age, 58.6 ± 8.2 years) who underwent simultaneous bilateral MOWHTOs between December 2011 and January 2021. Locking compression plates were used for simultaneous bilateral MOWHTOs. The Oxford Knee Score (OKS) was used to assess clinical outcomes at the last follow up. Complications (lateral hinge fracture (LHF), nonunion, and loss of correction) were evaluated using postoperative serial plain radiography and computed tomography (CT). ResultsAt the last follow up (range, 2.0–11.1 years), the mean OKS for the 72 knees was 36.8 ± 10.4. According to the OKS, 42 knees (58.3%) scored ’excellent’, 16 (22.2%) scored ‘good’, eight (11.1%) scored ‘moderate’, and six (8.3%) scored ‘poor’. LHFs occurred in 11 of the 72 knees (15.3%). Among these, five LHFs were identified on postoperative plain radiographs and CT scans (acute LHFs), whereas six fractures were identified only on follow up plain radiographs (delayed LHFs). Loss of correction occurred in one patient with delayed LHFs. The patient required an additional surgical treatment to achieve bone healing at the osteotomy site. ConclusionSimultaneous bilateral MOWHTO is a viable treatment option for patients with bilateral medial osteoarthritis of the knee joint. Serial plain radiographs at short-term intervals are recommended to detect delayed LHFs and prevent complications such as fixation failure and loss of correction.

The effect of frontal plane osteotomy angle on lateral cortex fracture in medial open wedge high tibial osteotomy procedure

BackgroundPrecise high tibial osteotomy is crucial, especially for middle-aged individuals with medial compartment arthritis, aiming to prevent complications like lateral cortex fractures. This study explores how frontal plane osteotomy inclination impacts lateral cortex fractures during medial open-wedge high tibial osteotomy. MethodsUsing finite element analysis, tibia models underwent osteotomies at angles of 10°, 13°, 16°, 19°, and 22°, forming five models. Forces from 5 N to 75 N were applied incrementally, recording bone stresses (MPa) at the lateral hinge, angle changes (°) along the osteotomy line, and gap distances (mm). ResultsModels with higher frontal inclination showed increased gap distances under identical forces. For instance, at 5 N force, the 10° inclination model displayed a correction angle of 0.28° and a 1.43 mm gap, while the 22° model had a correction angle of 0.35° and a 1.37 mm gap. Under 75 N force, the 10° model had a correction angle of 10.81° and a 14.02 mm gap, while the 22° model had a correction angle of 16.86° and a 19.31 mm gap. ConclusionThe osteotomy starting point’s distance from the joint doesn’t significantly impact final stress on the lateral cortex when the same gap distance is achieved. However, in cases requiring a higher degree of correction, we can say that the surgeon can achieve the result with less resistance by keeping the osteotomy starting point more distal to the joint line.

Is severe medial knee osteoarthritis a risk factor for dissatisfaction following medial open-wedge high tibial osteotomy in patients 55 years of age or younger?

Although previous studies have shown that severe medial knee osteoarthritis (OA) (Kellgren-Lawrence grade IV) is a risk factor for patient dissatisfaction following medial open-wedge high tibial osteotomy (MOWHTO), it is uncommon to perform arthroplasty as a primary surgical option in patients 55 years of age or younger. Thus, the purpose of our study was to evaluate whether severe medial knee OA is a risk factor for dissatisfaction following MOWHTO depending on patient age based on a cutoff of 55 years. We retrospectively reviewed the data of 270 consecutive patients who underwent MOWHTO with a minimum of 2 years of follow up. Patients were divided into 2 groups based on satisfaction following surgery, a Satisfied group (new Knee Society Score satisfaction subscore >20) and a Dissatisfied group (≤20). In order to assess risk factors for patient dissatisfaction depending on the age range, a subgroup analysis was conducted based on a cutoff age of 55 years. Preoperative demographics, OA grade, articular cartilage and meniscus status, severity of varus deformity, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and surgical factors were compared. At 2 years after surgery, binomial logistic regression analysis showed that severe medial knee OA was associated with patient dissatisfaction following HTO in the entire cohort (odds ratio [OR] 4.557, 95% confidence interval [CI] 2.300-9.030, p < 0.001). In subgroup analysis depending on age range, severe medial OA was not a risk factor for dissatisfaction in the age ≤55 years group. However, severe medial knee OA in the age >55 years group was a significant risk factor for dissatisfaction after MOWHTO (OR 6.78, 95% CI 2.979-15.431, p < 0.001). Severe medial OA was not a risk factor for dissatisfaction in patients age 55 years or younger who underwent MOWHTO. Therefore, surgeons can take this result into account when counseling younger patients considering MOWHTO. III.

Analysis of the distribution of mechanical load on the plate and lateral hinge of a valgus-producing open wedge high tibial osteotomy during weight-bearing by simulating consolidation. Finite element study.

High tibial osteotomy (HTO) is indicated for managing isolated medial knee osteoarthritis in a young patient with a metaphyseal deformity of the proximal tibia. In a medial open-wedge HTO, maintaining the integrity of the hinge is crucial for consolidation and preservation of the correction. Based on a validated model and preliminary results, the objective of this work was to measure and monitor the distribution of mechanical load on a locking fixation plate and the lateral hinge of an HTO using a finite element (FE) model during different phases of consolidation evolution, simulating single leg weightbearing. The working hypothesis was that with increasing consolidation, the stresses significantly decrease on both the plate and the lateral hinge, but with greater magnitudes on the plate and approaching zero on the hinge. A validated numerical model of a high tibial osteotomy (HTO) fixed with a locking plate on a real proximal tibial geometry (using Autodesk Fusion 360 and Altair HyperWorks software) was used. An axial load equivalent to one body weight was applied. Five scenarios were considered, resulting in five different models by varying, in the FE model, the Young's modulus of the trabecular and cortical bone, which allows for simulating the evolution of consolidation. Consolidation scenarios were tested by varying the mechanical properties of the HTO gap filling: 25% of normal bone properties, then 50%, 75%, and finally 100%, which is hypothetically considered as remodeled bone. The primary outcome measure was the maximum stress value in the areas of interest (Von Mises stresses, in MPa), specifically at the plate and lateral hinge. The decrease (in %) is major as early as the simulation of 25% consolidation in both areas of interest: a reduction of 91% on the plate and 93% on the hinge. The reduction in absorbed stresses continues in both areas, but with a more pronounced decrease on the plate. It is noteworthy that from 50% consolidation, under these experimental conditions, stresses remain comparable on the hinge, especially between 75% and 100% consolidation. The hypothesis is confirmed with a more marked decrease on the plate and approaching zero on the hinge, which seems logical in a consolidation process. Comparison with the literature is challenging, as only one finite element study has analyzed the influence of consolidation on the stresses absorbed by an HTO plate, but with different consolidation thresholds and without studying the hinge. This study has limitations: the model construction conditions, it is a finite element computer study, and the weight-bearing simulation for this study was static, which does not address the distribution of stresses during walking, this model is defined for a given valgus HTO plate and a specific opening and does not allow for extrapolation to distal femur opening osteotomies nor in clinical practice. The hypothesis is confirmed; however, further studies are needed to validate these numerical results: an experimental part on instrumented cadaveric bone and comparative studies of fixation plates are necessary. V; expert opinion, controlled laboratory study.

Simoultaneous bilateral medial opening wedge high tibial osteotomy can be performed safely and effectively without bone grafting: analysis of a monocentric retrospective series

BackgroundSimultaneous bilateral high tibial osteotomy (SBHTO) is a potential solution to treat bilateral medial osteoarthritis (OA) associated with tibial varus deformity. Concerns on the potential problems related to bone healing exists, and most of the surgeon performing SBHTO use bone void filler as associated procedure.This paper aim to evaluate safety and efficacy of SBHTO using locking plate, autologous cancellous bone mobilization and no bone void filler with immediate weight bearing at tolerance protocol.MethodsConsecutive patients performing primary SBHTO between January 2019 and December 2022 were retrospectively evaluated. Functional and pain score, subjective satisfaction and complications were noted at 2, 3, 6 months and final follow up, with a minimum of 12 months.ResultsA total of 40 patients (80 knees) were included. Mean correction for each limb was 8.67° ± 2.24°. No patients presented with major complications. Pain was reduced but activity level worsened 2 months after surgery. All pain and functional scores improved significantly from months 3 up to final follow up. 95% of patients reported to be subjectively satisfied with surgery.ConclusionsThis paper showed that SBHTO can be performed safely and with good results without bone grafting the osteotomy gap, even for correction up to 12°. Pain improved already 2 months after surgery, while activity level and function start to improve at 3 months after surgery.Level of evidenceIV.