Medial Opening Wedge Research Articles

Effects of different hinge positions on tibial rotation in uniplanar medial opening wedge high tibial osteotomy with three-dimensional tibial models.

To investigate the effects of different hinge positions in the sagittal and axial planes on distal tibial rotation (DTR) during medial opening wedge high tibial osteotomy (MOWHTO) with three-dimensional tibial models. Preoperative CT data from 30 knee joints in 30 patients who underwent surgery for varus malalignment of knee were included. 1 standard hinge position (0°), 6 axial planes (±5°, ±10°, ±15°), and 6 sagittal planes (±5°, ±10°, ±15°) hinge positions were defined and virtual uniplanar osteotomy was performed. The correction angle of each model was generated using Fujisawa's point. Participants' baseline characteristics, radiologic parameters and DTR were measured. One-Way Repeated Measures ANOVA and single factor linear regression analysis were used to analyze the association between tibial rotation and hinge position in the sagittal and axial planes. We found a clear linear correlation between changes in hinge position in the sagittal plane and DTR. The changes in DTR were the smallest when the hinge position was at 5°, where internal or external rotation of the DTR may occur. When the front aspect of hinge axis rotated distally, DTR tended towards internal. Meanwhile, when the front aspect of hinge axis rotated proximally, DTR tended towards external. There were no correlations with every hinge axis position in the axial plane. It is sagittal but not axial hinge axis affects DTR in uniplanar MOWHTO with three-dimensional tibial models. In the sagittal plane, every change in hinge position was significantly linearly correlated with DTR. However, no linear correlations were observed between every hinge position change in the axial plane.

Changes and associations between synovial fluid and magnetic resonance imaging markers of osteoarthritis after high tibial osteotomy

BackgroundMechanobiological mechanisms of osteoarthritis (OA) are unclear. Our objectives were to explore: 1) changes in knee joint physiology using a large panel of synovial fluid biomarkers from before to one year after high tibial osteotomy (HTO) surgery, and 2) the association of changes in the synovial fluid biomarkers with the changes in MRI measures of knee effusion-synovitis and articular cartilage composition.MethodsTwenty-six patients with symptomatic knee OA and varus alignment underwent synovial fluid aspirations and 3 T MRI before and one year after medial opening wedge HTO. Cytokine and growth factor levels in synovial fluid were measured with multiplex assays. Ontology and pathway enrichment was assessed using data protein sets with gene set enrichment analysis (GSEA), and analyzed using linear mixed effects models. MRIs were analyzed for effusion-synovitis and T2 cartilage relaxation time using manual segmentations. Changes in biomarker concentrations were correlated to changes in MRI effusion-synovitis volume and articular cartilage T2 relaxation times.ResultsDecreased enrichment in Toll-like receptor and TNF-α signalling was detected one year after HTO. The leading contributors to this reduction included IL-6, TNF-α and IL-1β, whereas the highest contributors to positive enrichment were EGF, PDGF-BB and FGF-2. Effusion-synovitis volume decreased (mean [95%CI]) one year after HTO (-2811.58 [-5094.40, -528.76mm3]). Effusion-synovitis volume was moderately correlated (r [95% CI]) with decreased MMP-1 (0.44 [0.05; 0.71]), IL-7 (0.41 [0.00; 0.69]) and IL-1β (0.59 [0.25; 0.80]) and increased MIP-1β (0.47 [0.10; 0.73]). Medial tibiofemoral articular cartilage T2 relaxation time decreased (mean [95% CI]) one year after HTO (-0.33 [-2.69; 2.05]ms). Decreased T2 relaxation time was moderately correlated to decreased Flt-3L (0.61 [0.28; 0.81]), IL-10 (0.47 [0.09; 0.73]), IP-10 (0.42; 0.03–0.70) and increased MMP-9 (-0.41 [-0.7; -0.03]) and IL-18 (-0.48 [-0.73; -0.10]).ConclusionsDecreased aberrant knee mechanical loading in patients with OA is associated with decreased biological and imaging measures of inflammation (measured in synovial fluid and on MRI) and increased anabolic processes. These exploratory findings suggest that improvement in knee loading can produce long-term (one year) improvement in joint physiology.

"Accelerated postoperative rehabilitation protocol for Medial Open Wedge High Tibial Osteotomy enhances early return to routine activities"

ObjectiveThe primary objective of this research was to investigate the timeframe required for the resumption of daily activities following medial open wedge high tibial osteotomy (HTO) with accelerated rehabilitation protocol. Methodology: This study encompassed a cohort of 26 patients, consisting of 11 males and 15 females, all diagnosed with medial compartment osteoarthritis (grades 2 and 3). Each patient underwent medial open wedge HTO and was subsequently monitored for a minimum period of 8 weeks. Patients were advised to engage in early weight-bearing walking, with or without assistance, based on their comfort levels. The assessment of functionality involved the utilization of the Visual Analog Scale (VAS) score, Katz Index of Independence in Activities of Daily Living (ADL), and Lawton index, performed at intervals of postoperative day 1, 2 weeks, 4 weeks, 6 weeks, and 8 weeks. ResultsThe average age of the patients at the time of surgery was 51.5 ± 7.2 years. The mean preoperative VAS score registered at 8.6, which exhibited a substantial reduction to 1.3 at the 8-week postoperative follow-up (p < 0.001). On average, patients were capable of walking with full weight-bearing without any external support at 6.9 weeks post-surgery. The initial preoperative Katz index was tabulated at 6, and within 6 weeks, all patients had successfully regained their pre-surgery functional levels, restoring the Katz index to its original value of 6. In addition, the mean Lawton index both before surgery and at the 8-week postoperative mark remained stable, with no significant variation (n.s.). ConclusionsThe immediate outcomes observed in knee preservation surgery are indeed promising. Within the 8-week timeframe, a majority of patients successfully reinstated their preoperative levels of independence, accompanied by a notable alleviation of pain.

Alignment rod and gap measurement methods achieve comparable alignment correction in opening wedge high tibial osteotomy for varus osteoarthritic knees.

To compare clinical and radiological outcomes of medial opening wedge high tibial osteotomy (MOWHTO) using two different alignment methods: the alignment rod (AR) versus the gap measurement (GM) method. The primary outcome was to report the surgical accuracy of coronal plane corrections in each method. Patients who underwent MOWHTO with either AR or GM method between 2014 and 2022 at a single institution, with a minimum of 2 years of follow-up, were included. The opening gap was gradually spread with an AR under fluoroscopic control in the AR group, whereas the osteotomy site was opened to the value of the measured gap distance in addition to the thickness of the bone saw in the GM group. Radiological assessment of geometric characteristics included hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), mechanical lateral distal femoral angle and joint line convergence angle. Surgical accuracy, which is the deviation (Δ) between the intended and achieved correction, was compared between both methods. Clinical outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Scores. A total of 110 patients (n = 110 knees) with a mean age of 54.1 ± 8.4 years were included in the study. Radiological parameters were significantly improved as reflected by HKA correction from 171.6° ± 2.0° to 181.1° ± 2.6° in the AR group and from 171.0° ± 2.3° to 181.1° ± 2.8° in the GM group at 2 years (Intergroup n.s). There was no significant intergroup difference for all radiological parameters and clinical outcomes. There was no intergroup difference in the surgical accuracy as evaluated by Δvalues and absolute Δvalues of both HKA and MPTA (n.s). Comparable correction accuracy was achieved in MOWHTO using either the AR or GM method. The GM method is simple and reliable in achieving the intended correction in MOWHTO. Ⅲ retrospective comparative study.

Evaluating the Effectiveness of a Structural Allograft in Medial Open Wedge High Tibial Osteotomy in Patients With and Without a Lateral Hinge Fracture.

A lateral hinge fracture is a common complication in medial open wedge high tibial osteotomy (MOWHTO) and is associated with delayed union or nonunion. A comparison of outcomes between patients with or without a lateral hinge fracture after MOWHTO with a structural allograft has not been investigated. To validate the outcomes of MOWHTO with a structural allograft, especially in the presence of a lateral hinge fracture. Case series; Level of evidence, 4. We conducted a single-surgeon cohort study at a tertiary referral hospital between April 2017 and August 2022 and included patients who had undergone MOWHTO with a structural allograft for isolated medial compartment osteoarthritis with genu varum. We compared the incidence of delayed union or nonunion events and functional scores between patients with a lateral hinge fracture and those without using the Fisher exact test and independent t test. A total of 88 MOWHTO procedures (77 patients) were analyzed. The overall incidence of lateral hinge fractures was 29.5% (n = 26), including type I (n = 20 [22.7%]) and type II (n = 6 [6.8%]). Notably, 42.3% (n = 11) of these fractures had not been detected intraoperatively but during the follow-up visits. The overall Knee Society Score (KSS), Knee Society Score-Function (KSS-F), and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were 90.0 ± 10.0, 93.4 ± 10.8, and 93.8 ± 7.1 points, respectively. None of the patients had delayed union or nonunion, and none underwent a reoperation because of bony union problems. The functional scores (KSS, KSS-F, and WOMAC) were not different between patients who had a lateral hinge fracture and those who did not (P > .05). The routine use of a structural allograft was associated with satisfactory outcomes after MOWHTO, regardless of whether there was a lateral hinge fracture.

Maintaining Posterior Tibial Slope and Patellar Height During Medial Opening Wedge High Tibial Osteotomy: Response

Maintaining Posterior Tibial Slope and Patellar Height During Medial Opening Wedge High Tibial Osteotomy: Response

Finite element analysis confirms the optimal apex position in medial opening wedge high tibial osteotomy to avoid lateral hinge fracture.

Lateral hinge fracture is a significant complication of medial opening wedge high tibial osteotomy. While fracture risk is closely associated with the osteotomy apex position, the optimum position remains variable within the literature. Our hypothesis is that stresses at the osteotomy apex predicted by finite element analysis can be used to identify an apex position which minimises intra and postoperative fracture risks. A finite element model was studied to investigate the effect of varying the hinge position on fracture risk and severity for a given bone geometry; variables analysed included stress, strain and micromotion levels. Nine further knee models were studied to assess the variability between patients' bone properties and examine the effect of apex location on strains. Lateral hinge width and height significantly influence intra-operative stress, strain, and fracture risk, while hinge width predominately determines postoperative stability. Wider hinges improve postoperative stability, but increase the likelihood of intra-articular fractures. Aiming the apex at the fibular head height minimises strain. The osteotomy apex should be located such that the hinge width is equal to 13% of the medial-lateral width to minimise apex stress and fracture risk while preserving sufficient bone at the hinge for stability. The height of the apex from the tibial plateau should maintain a minimum value of 16% of the medial-lateral width to avoid intra-articular fracture, with the apex below the fibula head if necessary. The size of the tibia does not alter the optimal location, making our findings applicable across all tibia sizes. Our study has investigated and verified a proposed optimal apex position, based upon fracture risk prediction and micromotion at the osteotomy apex. This is clinically useful due to the potential use of the apex point on preoperative 2D radiographs when planning surgery. Not applicable.

Superficial Medial Collateral Ligament Transection Sufficiently Increases Joint Space Width for Medial Meniscal Procedures During Medial Open-Wedge High Tibial Osteotomy

Superficial Medial Collateral Ligament Transection Sufficiently Increases Joint Space Width for Medial Meniscal Procedures During Medial Open-Wedge High Tibial Osteotomy

Is microfracture sufficient for high-tibial osteotomy, or should intra-articular hyaluronic acid and oral glucosamine-chondroitin be used as additional treatments?

BackgroundThis study aimed to compare the effects of microfracture (MF) versus intra-articular hyaluronic acid (HA) + oral glucosamine and chondroitin sulfate (GC) in addition to MF in patients with osteoarthritic knees who underwent medial open wedge high tibial osteotomy (MOWHTO) after an average follow-up of five years.MethodsThe study was designed retrospectively and included patients who underwent MOWHTO due to gonarthrosis, the MF method performed on these patients, and HA + GC treatments applied in addition to MF. Three groups consisting of 79 patients were formed: only HTO (Group 1), HTO + MF (Group 2), and HTO + MF + HA + GC (Group 3). The groups were compared using knee injury and osteoarthritis outcome score (KOOS), visual analog scale (VAS) for pain, and range of motion (ROM). The associations between the degree of correction and function and pain were evaluated. Additionally, the KOOS subparameters were compared between the groups.ResultsThere were significant improvements in the postoperative KOOS and VAS scores in all three groups (p < 0.05). However, the ROM did not improve in Group 1. There was no significant difference in the postoperative KOOS, VAS, or ROM values ​​between Groups 2 and 3, but these values ​​were significantly better in Groups 2 and 3 than in Group 1 (p < 0.05). When the degree of correction increased, there were no significant positive changes in the postoperative KOOS or VAS score in Group 1, unlike in the other two groups (p < 0.05). In corrections of ≥ 10°, while there was no significant difference in the postoperative KOOS or VAS score ​​between Groups 2 and 3, these parameters significantly improved in these two groups compared to Group 1 (p < 0.05). Among the KOOS subparameters, pain and activities of daily living scores ​​were greater in Groups 2 and 3 than in Group 1 (p < 0.05).ConclusionsIn MOWHTO, MF is a sufficient treatment method that improves the patient’s clinical condition without requiring additional treatments such as HA and GC.Level of evidenceIII, retrospective cohort study.

Association of Undercorrection With Residual Proinflammatory Gene Expressions and Clinical Outcomes After Medial Open Wedge Proximal Tibial Osteotomy

Background: Accumulating evidence suggests that synovial inflammation plays a pivotal role in knee osteoarthritis. Although biomechanical findings have shown that medial open-wedge proximal tibial osteotomy (OWPTO) decreases medial compartment loading by correcting knee alignment, the relationship between knee alignment and synovial inflammation in the biological microenvironment has not yet been elucidated. Purposes: To investigate the relationship between preoperative and postoperative knee alignment and synovial gene expression and to determine the cutoff point of postoperative knee alignment at which gene expression of synovial inflammation improves. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 36 patients with osteoarthritis who underwent OWPTO between June 2018 and May 2020 were enrolled. Synovial tissue was collected from affected knees during initial OWPTO and plate removal surgeries, and gene expression associated with the pathogenesis of osteoarthritis in the synovial tissue was investigated using real-time polymerase chain reaction. The correlation between weightbearing line ratio (WBLR) and synovial gene expression was determined. Receiver operating characteristic curve analysis was used to determine the cutoff values of WBLR for improving gene expression. The participants were divided into 2 groups, according to the cutoff values of their WBLR, and compared according to Knee injury and Osteoarthritis Outcome Score (KOOS) and synovial gene expression. Results: Postoperative WBLR was correlated with gene expression of interleukin 1β (IL1B) (ρ = −0.43; P = .008) and of interleukin 6 (IL6) (ρ = −0.41; P = .01). The cutoff value to predict improvement of IL6 was postoperative WBLR of 52%, with an area under the curve of 0.74 (P = .03). Patients with WBLR of <52% showed higher postoperative inflammatory gene (IL1B [P = .04] and IL6 [P = .03]) and inferior postoperative KOOS values compared with those with WBLR of >52%. Conclusion: The novel cutoff alignment for biological improvement after OWPTO in patients with medial compartment osteoarthritis was determined to be WBLR of 52%, and WBLR of <52% was associated with higher residual intra-articular inflammation and poor clinical outcomes. After accounting for surgical errors, the surgeon should set the target surgical alignment so that the postoperative WBLR does not fall below 52%.

Medial open wedge osteotomy yields comparable stability to lateral open wedge procedure on the distal femur.

Supracondylar osteotomies are a frequently and successfully used technique in the treatment of coronal plane deformities and unicompartmental osteoarthritis of the knee. While lateral open wedge techniques are common for valgus deformities, the data about medial open wedge techniques for varus deformities is sparse. The aim of this study was to compare the biomechanical properties of medial and lateral open wedge osteotomies using a locking Tomofix® plate (DePuy Synthes, Oberdorf, Switzerland). Our hypothesis was that there would be no difference regarding biomechanical outcome parameters between these two groups. Medial and lateral open wedge osteotomies were performed in composite bone model as routine. Each experimental group contained 6 constructs. Standardized osteotomy gaps of ten millimeters were performed and Tomofix® plates were fixed to third generation composite bones. The constructs were subsequently mounted into a servohydraulic testing machine. Axial and torsional loadings were applied as described in previous experimental studies. All specimens were subject to a load to failure mode with the mechanism of failure being noted. Both experimental groups showed comparable biomechanical properties under axial and torsional loadings. Mean high force axial stiffness was 3772 N/mm for lateral and 4185 N/mm for the medial construct. Significant differences were noted for torsional stiffness under low- (0 N) and mid-force (150 N) loadings (P = 0.002; P = 0.009), favoring the medial open wedge constructs. Medial open wedge osteotomy yields comparable biomechanical stability to the lateral open wedge procedure on the distal femur in a composite bone model.

Medial open wedge high tibial osteotomy is a viable option in young patients with advanced arthritis in a long-term follow-up.

This study aimed to evaluate the long-term outcomes of medial open wedge high tibial osteotomy (MOWHTO) as a treatment option for advanced medial compartment knee osteoarthritis (OA) Kellgren-Lawrence (K-L) III and IV. Patients with severe medial compartment arthritis, who underwent MOWHTO with locking plate between 2003 and 2015, were retrospectively reviewed. A locking plate for the osteotomy was utilized. Preoperative and postoperative patients' evaluation was performed using the International Knee Documentation Committee Score (IKDC), the Oxford Knee Score (OKS), the Knee Injury Osteoarthritis Outcome Score (KOOS) and the Short Form-12 Score (SF-12). Standardized standing whole-limb X-rays were taken to evaluate the mechanical tibiofemoral angle (mTFA) and proximal medial tibial angle (PMTA), and the severity of OA. A total of 32 patients, 35 knees (27 males, five females) of which 21 were classified as K-L Grade III and 14 as K-L Grade IV, and mean age 47.1 ± 9.17 years old, who were followed for 13.6 years (range 7-20 years), were included in the study. During the follow-up period, three knees required conversion to total knee replacement (91.5% survival rate). All clinical outcome scores (KOOS, OKS, IKDC and SF-12) showed a significant improvement compared to preoperative status (p < 0.05). Preoperative mTFA and PMTA were significantly corrected immediately after surgery and retained this improvement at the last follow-up. MOWHTO with a locking plate is an effective method to treat severe medial compartments. Clinical and radiological results are satisfactory and the survival rate is 91.5%, at a mean follow-up of 13.6 years after the procedure. Level IV.

Medial opening wedge high tibial osteotomy performs similarly irrespective of body mass index.

This study investigates the effect of the body mass index (BMI) on the early (2 years) to midterm (5 years) results of medial opening wedge high tibial osteotomy (MOWHTO). A prospectively maintained single-centre database of 1138 knee osteotomies, between 2002 and2022, was retrospectively reviewed. Adult patients who underwent MOWHTO for symptomatic unicompartmental medial knee osteoarthritis (OA), with varus knee malalignment, having failed conservative management, were included. Patients were categorized into threegroups according to their BMI as per the classification from the National Institute for Health and Care Excellence (NICE): the healthy weight (HW) group (BMI of 18.5-24.9 kg/m2), the overweight (OW) (BMI of 25-29.9 kg/m2), and the obesity (OB) group (BMI ≥ 30 kg/m2). Multiple patient-reported outcome measures (n = 6) were recorded preoperatively and at 2 and 5 years postoperatively. Deformity analysis was undertaken preoperatively and postoperatively. The relative risk (RR) of the complications between the HW, OWand OB groups was calculated. The rate of conversion to arthroplasty, and 5and 10 years survivorship were recorded, as well as the hazard ratio (HR) of BMI on survivorship. A total of 574 cases were included in the study: the HW group (n = 96), the OW group (n = 233)and the OB group (n = 245), with a mean BMI of 23 ± 1.5 kg/m2, 27.4 ± 1.4 kg/m2 and 34.4 ± 3.8 kg/m2, respectively. The mean follow-up was 13.3 years (4.8-20.3). The mean mechanical tibiofemoral angle corrections were in the HW group: 7.1 ± 3°, OW group: 6.6 ± 3.5°and OB group: 7.1 ± 3.8°, with no intergroup significant difference (p = n.s.). Clinically, despite lower preoperative scores in the OW and OB groups, no difference was observed postoperatively amongst the three groups. The overall complication rate was 12.5% in the HW group, 6.8% in the OW group, and 9.8% in the OB group. There was no significant difference in the RR of complications between the HW and OW groups (RR = 0.6, 95% confidence interval [CI] = 0.3-1.3)(p = 0.2), and the HW and OB groups (RR = 0.8; 95% CI = 0.3-2.2)(p = 0.7). There was no overall significant difference in survival outcomes based on the BMI between the threegroups (p = 0.4). The HR of conversion to arthroplasty between the HW and OW groups was 1.4 [95% CI = 0.6-3.5](p = 0.5)and between the HW and OB groups was 1.8 [95% CI = 0.8-4.4] (p = 0.2). BMI has no significant effect on either the radiological corrections, clinical outcomes, complicationsor survivorship of MOWHTO at short- to medium-term follow-up. No specific cutoff point for BMI can be recommended as a contraindication to MOWHTO. Level IV, Retrospective cohort study.

Intraoperative Complications in Medial Opening Wedge High Tibial Osteotomy.

Medial opening wedge high tibial osteotomy has been established for treatment of medial symptomatic knee arthrosis with varus malalignment in young and elderly but active patients. To obtain satisfactory results, it is essential for surgeons performing osteotomy to identify, prevent, and treat potential intraoperative adverse events. Lateral hinge fracture (LHF) is the most common intraoperative complication while popliteus artery injury is rare but limb-threatening. Computed tomography is the benchmark to detect LHF, the risk of which increased markedly with the opening gap larger than 11 mm. Setting the lateral hinge in a safe zone is the most important preventive measure. Medial long locking plate fixation may allow patients even with unstable hinge fractures to start early full weight bearing. Additional fixation of LHF is optional, and bone void filling is not routinely used. For protection of popliteus artery injury, flexing the knee joint is unreliable. It is paramount to place a protective retractor just behind the posterior tibial cortex toward the proximal tibiofibular joint before osteotomy, particularly in case of aberrant artery. A repertoire of surgical pearls is described in detail in this review to identify, prevent, and manage those intraoperative complications.

Patellar height changes sequentially after medial open wedge high tibial osteotomy: Evaluation using shear wave elastography

BackgroundThis study was performed to evaluate changes in patellar tendon tissue after medial open wedge high tibial osteotomy (MOWHTO) using shear wave elastography (SWE) and to clarify the factors contributing to patellar height changes after MOWHTO. MethodsThe study cohort comprised 24 knees of 24 patients. Patellar tendon length, thickness, and elasticity were evaluated using SWE preoperatively, 2 weeks postoperatively, and 3, 6, and 12 months postoperatively. The Caton–Deschamps index (CDI) was also measured at these time points. Lower limb alignment and factors related to sequential changes in patellar height were evaluated. ResultsThe CDI was significantly different between preoperatively and 2 weeks postoperatively and between 2 week postoperatively and 3, 6, and 12 months postoperatively (p < 0.05 for all) The patellar tendon length at 12 months postoperatively was significantly shorter than that at 2 weeks postoperatively. The postoperative patellar tendon thickness was thicker than preoperative patellar tendon at all sites. The postoperative patellar tendon thickness significantly increased from preoperatively at middle and distal sites. The only factor associated with Δpre-post2WCDI (preCDI − post2WCDI) was ΔMPTA(medial proximal tibial angle) (postoperative MPTA – preoperative MPTA) (p = 0.042). The significant predictor of Δpost2W-post12MCDI was Δpost2W-post12 M distal elasticity (p = 0.022). ConclusionPatellar height changed sequentially after MOWHTO. The factors that caused patellar height change were related to the change in patellar tendon quality after OWHTO.

The Osteotomy Gap Filling Rate of Multiple Time Points After Medial Opening Wedge High Tibial Osteotomy Without Bone Graft

BackgroundThe purpose of the present study was to analyze osteotomy gap filling of multiple time points until 2 years post-medial opening wedge high tibial osteotomy (MOWHTO). The absolute value of gap filling and postoperative changes relative to the preoperative void osteotomy gap were evaluated using computed tomography (CT) at each time point. MethodsData of 30 patients who underwent MOWHTO between September 2019 and July 2021 were retrospectively analyzed. Surgical procedures without bone grafts were performed; a standardized rehabilitation protocol was implemented. The osteotomy gap filling rate was measured using computed tomography scans at the immediate postoperative period and at 6, 12, and 24 months after surgery. Statistical analyses were performed to assess changes over time. ResultsThe osteotomy gap filling rate showed a significant continuous increase after MOWHTO, reaching 45.2% at 6 months and 66.7 and 84.4% at 1 and 2 years, postoperatively, respectively. The most substantial increase occurred within the initial 6 months, thus indicating a critical period for bone healing. ConclusionsThe osteotomy gap filling rate showed a significant and gradual increase from immediately after surgery to 2 years after MOWHTO without bone grafting, the greatest of which was achieved in the initial 6-month period. Therefore, this study may be helpful for planning postoperative rehabilitation, including the extent of weight-bearing load and the period of crutch use. Study designCase series; Level of Evidence IV.

Maintaining Posterior Tibial Slope and Patellar Height During Medial Opening Wedge High Tibial Osteotomy: Letter to the Editor

Maintaining Posterior Tibial Slope and Patellar Height During Medial Opening Wedge High Tibial Osteotomy: Letter to the Editor

Learning curves for high tibial osteotomy using patient-specific instrumentation: a case control study.

Three-dimensional (3D) planning and Patient Specific Instrumentation (PSI) can help the surgeon to obtain more predictable results in Medial Opening Wedge High Tibial Osteotomy (mOW-HTO) than the conventional techniques. We compared the accuracy of the PSI and standard techniques and measured the learning curve for surgery time and number of fluoroscopic shots. We included the first 12 consecutive cases of mOW-HTO performed with 3D planning and PSI cutting guides and the first 12 non-supervised mOW-HTO performed with the standard technique. We recorded surgery time and fluoroscopic time. We calculated the variation (Δ delta) between the planned target and the postoperative result for Hip Knee Ankle Angle (HKA), mechanical medial Proximal Tibia Angle (MPTA), Joint Line Convergence Angle (JLCA) and tibial slope (TS) and compared it both groups. We also recorded the complication rate. We then calculated the learning curves for surgery time, number of fluoroscopic shots, Δ from target in both groups. CUSUM analysis charts for learning curves were applied between the two groups. Mean surgical time and mean number of fluoroscopic shots were lower in PSI group (48.58±7.87 vs. 58.75±6.86 min; p=0.034 and 10.75±3.93 vs. 18.16±4.93 shots; p<0.001). The postoperative ΔHKA was 0.42±0.51° in PSI vs. 1.25±0.87° in conventional, p=0.005. ΔMPTA was 0.50±0.67° in PSI vs. 3.75±1.48° in conventional, p<0.001; ΔTS was 1.00±0.82° in PSI vs. 3.50±1.57° in conventional, p<0.001. ΔJLCA was 1.83±1.11° in PSI vs. 4±1.41° in conventional, p<0.001. The CUSUM analysis favoured PSI group regarding surgery time (p=0.034) and number of shots (p<0.001) with no learning curve effect for ΔHKA, ΔMPTA, ΔJLCA and ΔTS. PSI cutting guides and 3D planning for HTO are effective in reducing the learning curves for operation time and number of fluoroscopic shots. Accuracy of the procedure has been elevated since the first cases.

Application of Autologous Bone Graft versus Non Grafting in Medial Opening Wedge High Tibial Osteotomy Less than 14 mm: A Systematic Review and Meta-Analysis

Abstract Background Unicompartmental Knee osteoarthritis KOA due to varus malalignment is increased in young active patients which occurs predominantly in the medial compartment. Aim of the Work The objective of this study to compare MOWHTOs with autologous bone graft and without bone graft (wedge space mean less than 14 mm) in treatment of unicompartmental KOA and varus malalignment of the knee to determine which is better in decision-making according to outcomes. Patients and Methods Studies that matched the inclusion criteria were included in this meta-analysis. participants with medial compartmental knee osteoarthritis and varus malalignment were shown in the investigation. The age of the participants was unrestricted. Plate as a fixation method was the only option regardless of plate type. During 2000 and 2021, a research study of internet databases (Egyptian Universities Research, Medline, PubMed, Cochran library, medical journals) was conducted. Following that, the references from the user research were examined, and specialists were approached for assistance in locating other papers. Two independent reviewers extracted data separately and cross-checked it. Results The Knee Society Knee score (KSKS) and Knee Society Function score (KSFS) are most commonly used for the assessment of the knee joint reveled that there is no statically significant difference between bone graft vs non graft. Regarding this systematic review the radiological outcomes, the clinical bone union and the full weight bearing movement, are rendering any statistical analysis meaningless. Regarding complications presented, there was a similar tendency for complication rate when compared according to grafting or non- grafting. The use of autograft accelerates radiographic healing of the osteotomy gap after OWHTO while shorten the union time but confers no advantages in terms of functional or patient elated out comes at 3 or 12 months postoperatively. Conclusion MOWHTO can be performed without a graft with less operative time and avoiding graft harvest comorbidity with similar clinical and radiological results regarding bone union and posterior tibial slope alteration and knee scores.

Equal rates of bone healing and reduced surgical time with iliac crest allograft compared to autograft in medial opening wedge high tibial osteotomy: a randomized controlled clinical trial.

Iliac crest autograft is frequently used to fill in bone defects after osteotomies. Nonetheless, surgery for bone autograft procurement is associated with morbidity and pain at the donor site. Alternatives to it have been explored, but there is no consensus to guide their application as a routine practice in several orthopedic procedures. Thus, this study was designed to compare the efficacy and safety between iliac crest autograft and allograft in medial opening wedge high tibial osteotomy. Forty-seven patients with a symptomatic unilateral genu varum and an indication for high tibial osteotomy were randomly assigned to receive either autograft or allograft to fill the osteotomy site. Operative time, bone healing, and complication rates (delayed union, nonunion, superficial and deep infection, loss of correction, and hardware failure) were recorded after a one-year follow-up. Data were expressed as Mean ± Standard Deviation and considered statistically significant when p < 0.05. The time to radiologic union was similar between both groups (Allograft: 2.38 ± 0.97 months vs. Autograft: 2.45 ± 0.91 months; p = 0.79). Complication rates were also similar in both groups, with one infection in the allograft group and two in the autograft group, two delayed unions in the allograft group, and three in the autograft group. The operative time differed by 11min between the groups, being lower in the allograft group (Allograft: 65.4 ± 15.1min vs. Autograft: 76.3 ± 15.2min; p = 0.02). Iliac crest allografts can be safely and effectively used in medial opening wedge high tibial osteotomy as it promotes the same rates of bone union as those achieved by autologous grafts, with the benefits of a shorter operative time. U1111-1280-0637 1 December 2022, retrospectively registered.