Open Wedge High Research Articles

Open Wedge High Tibial Osteotomy with Pes Anserinus Preservation and Insertion of Bone Substitutes

Biplanar open wedge high tibial osteotomy (OWHTO) has become common since the introduction of OWHTO-specific plates. However, the management of soft tissues, including skin, the pes anserinus, and the superficial medial collateral ligament (sMCL) release vary among surgeons. We introduce an OWHTO methodology that avoids pes incision and repair, uses bone substitute insertion into the opening gap and includes management of soft tissues to minimize complications. We adopted a reversed curved oblique incision to reduce the risk of saphenous nerve injury. We avoided pes incision, taking advantage of its posterior component force to allow it to function as a compressor of the ascending osteotomy site. The proximal component force of the pes provides compression between the bone substitute insertions and the proximal/distal cortices. This allows postoperative weight bearing to be distributed to the substitute, which may reduce the risk of implant failure. The sMCL is detached from the distal tibial attachment without cutting, enabling its return to its original position underneath the pes and to be repaired. This sMCL release with complete pes preservation may reduce the risk of deep infection or medial laxity during total knee arthroplasty conversion, and further reduce the risks of OWHTO.

Effect Analysis of Open Wedge High Tibial Osteotomy for Medial Compartment Osteoarthritis of Knee Joint

Effect Analysis of Open Wedge High Tibial Osteotomy for Medial Compartment Osteoarthritis of Knee Joint

Comparison of the Functional and Radiological Outcomes of Single- and Two-Stage Bilateral Open Wedge High Tibial Osteotomy.

This study compared the functional and radiological outcomes and complications of single- (SS) and two-stage (TS) bilateral high tibial osteotomy (HTO). From 2014 to 2018, 48 patients underwent bilateral HTO surgery for osteoarthritis. The outcomes of SS in 28 knees and TS in 32 knees were compared using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Oxford Knee Score (OKS) as functional outcomes, and the medial proximal tibial (MPTA), hip-knee-ankle (HKA), tibial slope (TSA) angles, and mechanical axis deviation (MAD) as radiological outcomes. We also evaluated the estimated blood loss (EBL). No significant differences in the pre- and postoperative mean OKS and KOOS were found between the groups. There was a significant difference between the groups in the last postoperative HKA angle (- 0.9 ± 3.9 and 1.8 ± 4.3°, respectively). In SS and TS, the respective total mean surgical time was 108 ± 28 and 143 ± 36 min (p < 0.001). The mean calculated EBL was 612 ± 267 and 544 ± 357 mL, respectively, (p = 0.5), and the mean length of stay (LOS) was 2.2 ± 0.83 and 3.5 ± 1.0 days, respectively, (p = 0.01). SS bilateral HTO is a safe reasonable option for certain patients with bilateral knee osteoarthritis because it involves a single hospitalization, one-time exposure to anesthesia risks, accelerated rehabilitation, earlier return to expected life status, reduced total hospital stay, and a likely decrease in total cost.

RADIOLOGICAL AND CLINICAL ANALYSIS OF BIPLANE OPENING WEDGE HIGH TIBIAL OSTEOTOMY FOR MEDIALLY ARTHRITIC VARUS KNEES FIXED BY LOCKING PLATE

Background: High tibial osteotomy is an established and helpful treatment for unicompartmental osteoarthritis associated with varus deformity. However, asupratubercle high tibial osteotomy leads to a decrease in patellar height making the technique not suitable in the case of concomitant patella Baja. Moreover, this kind of osteotomy can change in situ forces at the patellofemoral joint and the lateral patellar tilt. To widen the indication of high tibial osteotomy was proposed a biplane opening wedge high tibial osteotomy with a distal tuberosity osteotomy (B-OWHTO). Objective: To assess the clinical and radiological outcome of biplane open wedge high tibial osteotomy in the treatment of medially arthritic varus knees. Patient and Methods: Twenty varus knees (20) patients, with MCOA, were operated upon from 2019 to 2020 at Al-Azhar University Hospital (Assiut). They all had Medially Opening Wedge High Tibial (MOWHTO) using the biplanar technique and fixed by locking plates. We compared the data fetched preoperatively (at day 0 = D0) with data one year or more after surgery with a mean of 14.5 months (at year 1=Y1). The mean age was 49.39 ± 8.15 years old, 13 were females, while others were males. Eleven were right knees, and 7 were left. Types of occupation were; 9 employed, 7 unemployed. Sixteen were no sportive, and 2 were recreational athletes. Seven patients were normal weight, while 11 were overweight. Two patients were diabetic, and 2 were perceived as treated HCV infection. According to the MCOA K-L scale; 5 were grade 3, 9 were grade 2 and 4 were grade 1. Results: The mean western Ontario and Macmaster universities osteoarthritis index (WOMAC), value was 51.44 ± 26.8 and then dropped to 24. 39 ± 17.41. The difference was statistically significant (p-value was <0.001). The mean Cincinnati score was 40.36 ± 19.28 at D0, then 81.88 ± 14.45 at Y1. The rising pattern from D0 to Y1 was significant statistically (p-value was <0.001). For radiological results, the mean amount of correction was 10.56o ± 2.97o. The mean TS for the18 patients was 10.78o ± 2.92o and changed to 10.49o ± 2.51o, and this was statistically insignificant. Regarding the patellar height (PH), there was a statistically significant decreasing tendency from a mean of 1.02 ± 0.16 to 0.97 ± 0.15. LPT showed a statistically significant decrease, although quite small, from 10.48 o ± 6.18 o to 9.43o ± 4.27o. MOWHTO using biplanar technique and fixed by the locking plate without BG filling was a very efficient modality of treatment for adult patients suffering from medially arthritic varus knees in terms of clinical and radiological aspects. Conclusion: Medial Open Wedge High Tibial Osteotomy (MOWHTO) using biplanar technique and fixed by the locked plate without bone graft filling was a very efficient modality of treatment for adult patients suffering from medially arthritic varus knees in terms of clinical and radiological aspects.

Postoperative Bone Marrow Lesions (BMLs) Are Associated with Pain Severity in Patients Undergoing Open Wedge High Tibial Osteotomy (OWHTO).

The purpose of the study was to investigate the relationship between postoperative bone marrow lesions (BMLs) and pain severity in patients undergoing open wedge high tibial osteotomy (OWHTO). We reviewed the patients undergoing OWHTO between April 2018 and April 2020. The demographic and clinical data of patients were collected. Clinically, VAS and Knee injury and Osteoarthritis Outcome Score (KOOS) were used to assess pain level and functional outcomes of patients. The MRI Osteoarthritis Knee Score (MOAKS) was used to assess the total BMLs size in medial tibiofemoral (MTF), lateral tibiofemoral (LTF), and patellofemoral (PF) joints. 98 patients were enrolled in the study, including 57 male and 41 female patients. The VAS scores improved significantly from 6.1 ± 0.8 to 1.5 ± 0.9 (p < 0.001), and all subscales of KOOS improved significantly after surgery (p < 0.001). There were no significant differences between the pre- and postoperative total BML size of PF and LTF joints (p > 0.05). We observed significant improvements in the total BML size of MTF joint (p < 0.001). The VAS scores and KOOS pain scores improved better in patients without postoperative MTF joint BMLs (p < 0.001). Postoperative MTF joint BMLs were correlated with postoperative VAS (p < 0.001) and KOOS pain (p < 0.001). Our study demonstrates that MTF joint BMLs improved significantly after OWTHO. We confirmed that the presence of postoperative MTF joint BMLs are strongly associated with pain severity. The greater the improvement in postoperative MTF joint BMLs, the less pain. Our findings provide valuable understandings of OWHTO in the treatment of knee osteoarthritis (KOA) and potential future directions for KOA treatment approaches.

The Effect of Bone Marrow Aspirate Concentrate on Clinical Results Used with Open Wedge High Tibial Osteotomy

Objectives:Medial open wedge high tibial osteotomy is a widely used treatment method for early stages of medial compartment osteoarthritis, particularly in the middle aged patients. Correction of the malalignment of the knee and even distribution of the body weight through knee joint is considered to facilitate the regeneration of the damaged cartilage. Addition of a regenerative procedure to tibial osteotomies may enhance its potential effects. In this study we analyzed the effect of, if any, simultaneous use of BMAC with high tibial osteotomy.Methods:We have evaluated the clinical results of 46 knees of 38 patients that underwent open wedge high tibial osteotomy for early stage medial compartment arthrosis between 2017-2020. Patients were recruited into two groups as HTO only group (Group 1) and HTO+BMAC group (Group 2). Mean follow up time was 12.6 months. Preoperative International Knee Documentation Committee (IKDC) subjective score and Knee Society Score (KSS) of the patients were compared with those at the 1st, 3rd, 6th and 12th post-operative months. Wilcoxon Ranked Signed test was used to detect the significant difference.Results:Group 1 consisted of 18 female and 4 male patients, Group 2 consisted of 14 female and 2 male patients. Two patients in Group 1 received bilateral HTO and 6 patients in Group 2 received bilateral HTO+BMAC. Twenty four knees in Group 1 and 22 knees in Group 2 were included for evaluation. There was no significant improvement in the KSS and IKDC scores of the patients in Group 1 at the first follow-up, however at the 3rd month follow-up, KSS scores showed significant improvement (p<0,001) whereas IKDC scores did not show any improvement (p>0,005). Both KSS and IKDC scores showed significant improvement at the 6th and 12th months. (p<0,001). In Group 2, only KSS scores showed improvement at the 1st month follow-up (p<0,001). Both KSS and IKDC scores showed significant improvement at the 3rd, 6th and 12th month follow-up compared to preoperative scores.Conclusion:We believe that simultaneous use of BMAC with open wedge high tibial osteotomy for early stage medial compartment arthrosis may relieve pain at the early period and improve patient compliance to rehabilitation. Increase in range of motion promote the recovery period and provide rapid return to daily activities, thereby positively affecting cartilage regeneration.

Risk Factor Analysis for Infection after Medial Open Wedge High Tibial Osteotomy.

Background: Medial open wedge high tibial osteotomy (MOWHTO) is a well-established treatment for osteoarthritis of the medial tibiofemoral compartment. Surgical site infection (SSI) after MOWHTO is a devastating complication that may require further surgery. In this study, we aimed to identify the risk factors for infection after MOWHTO over 1 to 4 years of follow-up. Methods: Fifty-nine patients who underwent MOWHTO combined with knee arthroscopic surgery were included in this prospective study. Artificial bone grafts were used in all cases. Possible risk factors, including sex, age, body mass index (BMI), underlying disease, hospitalization length, correction angle, and surgery time, were recorded. Both univariate and multivariate analysis were used. Results: A total of 59 patients who underwent 61 operations were included. Eleven patients (18.0%) were reported to have SSI. Univariate analysis showed that smoking and diabetes mellitus were positively associated with SSI. Multivariate analysis showed that smoking and age were positively associated with SSI. Three patients (4.9%) were reported to suffer from deep SSI, requiring surgical debridement, all of whom were male smokers. Conclusion: Smoking, diabetes mellitus, and old age were identified to be possible risk factors of SSI after MOWHTO. These findings are common risk factors of SSI after orthopedic surgery according to the literature. Patient selection should be performed cautiously, and postoperative prognosis for MOWHTO should be carefully explained to patients who smoke.

Total Knee Arthroplasty Is Superior to Open Wedge High Tibial Osteotomy in Terms of Pain Relief for Patients With Osteoarthritis.

BackgroundGlobally, total knee arthroplasty (TKA) is widely performed on patients with osteoarthritis. Meanwhile, open wedge high tibial osteotomy (OWHTO) has garnered attention in our country as a joint-preserving procedure. This study aimed to retrospectively compare the postoperative clinical outcomes of TKA and OWHTO for patients with osteoarthritis.MethodsWe selected 94 patients (106 knees) who underwent OWHTO or TKA between 2013 and 2018, had complete clinical data, and were followed up for >2 years. Patients were classified into 2 groups depending on the procedure (TKA: n = 49; OWHTO: n = 45). Patients in the A (= arthroplasty) group were significantly older, with a worse range of motion (ROM) than those in the O (osteotomy) group. There were no significant differences regarding sex and body mass index between groups. Operative time, perioperative blood loss, knee ROM, and Japanese Knee Injury and Osteoarthritis Outcome Score (J-KOOS) were compared between the groups.ResultsSignificant differences were found between the A and O groups regarding operative time (120 ± 27.2 vs 80.3 ± 23.3 minutes), perioperative blood loss (505.4 ± 271.8 vs 322.6 ± 196.1 mL), knee ROM (flexion; 123.4 ± 16.3° vs 133.7 ± 12.8°), and J-KOOS for pain (87.4 ± 12.5 vs 78.1 ± 15.2 points) and symptoms (86.6 ± 12.3 vs 79.1 ± 13.3 points). There were no significant differences regarding other J-KOOS subscales.ConclusionsOWHTO involved shorter operative times and less blood loss. However, the O group reported less pain relief. The A group represents an older, likely less active patient population. Therefore, OWHTO is a possible joint-preserving treatment options in younger active patients who may not be interested in arthroplasty.

Open Wedge High Tibial Osteotomy Distal to the Tibial Tuberosity, is it a Superior Alternative? Review of the Literature

Open Wedge High Tibial Osteotomy Distal to the Tibial Tuberosity, is it a Superior Alternative? Review of the Literature

Genu Varum Correction: A Comparison of Conventional Open Wedge High Tibial Osteotomy versus Open Wedge Osteotomy with Sagittal Plane Cutting

Background: Open wedge high tibial osteotomy (OWHTO) is commonly utilized to correct genu varum. To decrease various complications of OWHTO, some modifications are needed. Methods: In a parallel randomized controlled clinical trial, 42 patients were divided into two groups: conventional OWHTO (control group) and OWHTO with the cut in the sagittal plane or distal tubercle osteotomy (OWHTO/DTO) (intervention group). Evaluation of the following items was conducted pre- and post-operatively: Knee Society Score (KSS) questionnaire, incidence of postoperative complications, patellar height by Blackburne-Peel (BP) ratio and Insall-Salvati Index (ISI), posterior tibial slope (PTS), tibiofemoral angle (TFA), Q-angle, medial proximal tibial angle (MPTA), three joint alignment radiography, and union radiological parameters. Results: The differences between preoperative and postoperative variables including the KSS, PTS, TFA, BP Index (BPI), ISI, MPTA, and Q-angle within the intervention and control groups were not statistically significant. In four cases (3 in the control group and 1 in the intervention group), the delayed union was observed but the complete union was achieved after a mean of 23 weeks. No nonunion was observed. Conclusion: Our results showed equal effectiveness for OWHTO/DTO compared with the conventional OWHTO.

Are There Harmful Effects of Preoperative Mild Lateral or Patellofemoral Degeneration on the Outcomes of Open Wedge High Tibial Osteotomy for Medial Compartmental Osteoarthritis?

Background:Early osteoarthritis of the knee joint mostly affects the medial compartment, making osteotomy a rational approach to slow the progression of the disease. However, some patients show asymptomatic mild degeneration in the lateral or patellofemoral compartment.Purpose:To evaluate the effect of asymptomatic mild lateral or patellofemoral degeneration on the outcomes of medial open wedge high tibial osteotomy (OWHTO) by assessing the outcomes according to the preoperative status of the lateral or patellofemoral degenerative changes.Study Design:Cohort study; Level of evidence, 3.Methods:A total of 114 patients (121 knees) who underwent biplanar OWHTO with second-look arthroscopic surgery and postoperative magnetic resonance imaging (MRI) were retrospectively enrolled. Patients were categorized into 4 groups according to the Osteoarthritis Research Society International (OARSI) and MRI Osteoarthritis Knee Score (MOAKS) classification systems. The International Cartilage Repair Society (ICRS) grade was used to evaluate the preoperative and postoperative cartilage status. Clinical outcomes were assessed by the American Knee Society (AKS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-item Short Form Health Survey (SF-36).Results:No degenerative changes in the lateral and patellofemoral compartments of knees (group I) were identified in 51.2% of cases (62 knees). Asymptomatic degenerative changes only in the lateral compartment (group II: OARSI grades 1-3 and MOAKS grades 1-3) were identified in 15.7% of cases (19 knees), changes only in the patellofemoral compartment (group III: OARSI grades 1-3 and MOAKS grades 1-3) were identified in 10.7% of cases (13 knees), and changes in both the lateral and the patellofemoral compartments (group IV) were identified in 22.3% of cases (27 knees). In the medial compartment, there was no significant difference in the improvement of MOAKS and ICRS grades among all groups (P = .813 and .985, respectively). In the lateral and patellofemoral compartments, there was no significant difference in the decline of MOAKS (P = .649 and .421, respectively) and ICRS grades (P = .927 and .676, respectively) among all groups.Conclusion:The presence of mild lateral or patellofemoral degenerative changes did not affect the MRI, arthroscopic, and clinical outcomes of OWHTO. However, long-term observations are necessary to draw definitive conclusions as to whether OWHTO can be indicated in such patients without harmful effects.

Use of 4.5 Non-locking Plate As an Alternative Device in Open Wedge High Tibial Osteotomy for Treating Varus Deformity

Background: High Tibial Osteotomy (HTO) is an approved surgical technique for varus knee deformity. For open wedge HTO multiple fixation methods and devices have been used. Advantages and disadvantages of these methods and devices are reported in various studies. Few studies have been conducted on use and final outcome of correction of varus knee deformity by implementation of non locking plates and benefits of this method is not fully evaluated. Objectives: To assess clinical and radiographic features of non-locking 4.5 millimeter L-buttress plate and T-buttress plate, which is used in open wedge High Tibial Osteotomy (HTO), and to find out whether this device is efficient enough or not. Methods: This cross-sectional study was conducted on 39 patients with tibial deformity recruited from a referral orthopedic hospital in Iran. Patients’ information, including their baseline characteristics, Range of Motion (ROM) of the knee, comorbidities, time of weight-bearing, union time in x-ray, graft type, and time of follow-up were reported at two stages: before and after the operation. Radiographic images were taken from their legs in both stages. Although different surgeons operated on the cases, they all used the same method. After the surgery, they were checked up in 2, 6, 12, and 24 weeks and a second alignment view was taken from the patients. Results: Thirty-nine patients underwent surgery for the correction of genu varus deformity and the follow-up time was between 6-48 months. There was no case of non-union and the ROM was perfectly restored in all the patients. Conclusion: Although the rate of the success in the use of the locking plate in HTO is higher, the use of a 4.5-mm non-locking plate seems to have decent results, too; therefore, it could be used as an alternative yet functional fixation tool in HTO.

Varus Deformity and Medial Opening Wedge High Tibial Osteotomy: Assessment on Short-Time Outcomes

Varus Deformity and Medial Opening Wedge High Tibial Osteotomy: Assessment on Short-Time Outcomes

Survival and Risk Factor Analysis of Medial Open Wedge High Tibial Osteotomy for Unicompartment Knee Osteoarthritis

The purpose of this retrospective study was to evaluate the survival rates and analyze the factors that affect survival rate after primary treatment with medial open wedge high tibial osteotomy (MOWHTO) for medial unicompartmental knee osteoarthritis. Clinical evaluation using Knee Society Score (KSS) and Western Ontario and McMaster Universities Osteoarthritis Index score and radiographic evaluation, including mechanical axis, were done before and after surgery. The main failure criteria for survival included the conversion to total knee arthroplasty or KSS of <60 points. Furthermore, risk factors that affected the survival after MOWHTO were analyzed. Three hundred thirty-nine knees were included after a minimum of 5years' follow-up. Their mean age was 56years, and mean follow-up duration was 9.6years. The mean KSS and Western Ontario and McMaster Universities Osteoarthritis Index scores were significantly improved after surgery (87.3 and 18.5 points at 5years and 81.7 and 23.6 points at 10years). The mean hip-knee-ankle (HKA) angle was corrected from 7.2° varus to 3.4° valgus 1year after surgery, which was maintained until 10years after surgery (2.9° valgus at 5years and 2.3° valgus at 10years, P > .05). Using Kaplan-Meier survival estimates, the probability of survival for MOWHTO was 96.8% at 5years, 87.1% at 10years, and 85.3% at 13years. The multivariate regression analysis revealed that age ≥65years (hazard ratio [HR]= 2.34, P= .046), medial compartment cartilage damage International Cartilage Repair Society grade ≥4 (HR= 2.46, I= .045), lateral compartment cartilage damage International Cartilage Repair Society grade≥2 (HR= 3.38, P= .006), postoperative HKA angle <0° (HR= 4.69, P < .001) were associated with failure. MOWHTO seems to be a good treatment option for young and active patients with medial knee osteoarthrosis and varus alignment, with acceptable survival rates and satisfactory outcomes. Age ≥65years, grade 4 cartilage damage in medial compartment, grade ≥2 cartilage damage in lateral compartment, and undercorrection of HKA angle appear to be significant risk factors associated with failure. Level IV: retrospective case series.

Disparity between Preoperative Target Correction Amount and Postoperative Correction Amount in Open Wedge High Tibial Osteotomy.

PurposeThe purpose of this study was to evaluate the disparity between the preoperative target correction amount and the postoperative correction amount in open wedge high tibial osteotomy (OWHTO) in patients divided according to the planned osteotomy gap.Materials and MethodsSeventy-two patients were divided into two groups (group 1 with the planned opening gap lager than the mean opening gap length of total patients and group 2 with a smaller opening gap). The opening gap was determined according to the target weight bearing line (WBL) ratio on the preoperative whole leg radiograph. Absolute and relative values of the disparity between the target and postoperative WBL ratios were compared between groups in order to clarify whether the disparity was deviated toward over- or under-correction.ResultsThe absolute value of disparity between the target and postoperative WBL ratios in group 1 was significantly larger than that in group 2 (6.01%±5.68% vs. 3.32%±3.38%; p=0.02). However, there was no statistically significant difference in relative values between groups (p=0.54).ConclusionsThe postoperative WBL ratio after OWHTO was different from the preoperative target WBL ratio if the planned osteotomy gap was large. This mismatch was not deviated toward one side, either over- or under-correction.

Effect of Fibular Height and Lateral Tibial Condylar Geometry on Lateral Cortical Hinge Fracture in Open Wedge High Tibial Osteotomy

To evaluate whether the fibular position and lateral proximal tibial geometry affect the osteotomy configuration and lateral hinge fracture (LHF) during open wedge high tibial osteotomy (OWHTO). From March 2014 to January 2016, patients who underwent OWHTO for isolated medial compartment osteoarthritis of the knee were retrospectively reviewed. To identify whether the fibular position and lateral proximal tibial geometry affect the osteotomy configuration, the fibular height, fibular anteroposterior position, lateral tibial condylar width, and lateral tibial condylar slope were evaluated on plain radiograph or computed tomography (CT). Thereafter, the correlation of these parameters with the thickness of the proximal fragment around the osteotomy end and LHFs was determined. A total of 123 OWHTOs including 30 LHFs (24.3%) were evaluated. High fibular head and small tibial condylar width and slope were related to thin thickness of the proximal tibial fragment, particularly on the posterior side (fibular height, P= .005; condylar width, P= .002; condylar slope, P= .01). The fibular height was shorter in the LHF group than in the non-LHF group on both plain radiography and CT (fibular height [plain radiography], 18.3 ± 1.6 vs 20.2 ± 2.1mm; P < .001; fibular height [CT], 17.4 ± 1.1 vs 19.6 ± 2.0mm; P < .001). The lateral tibial condylar width and slope were also smaller in the LHF group compared with the non-LHF group (tibial condylar width, 21.2 ± 4.9 vs 23.4 ± 4.5mm; P= .023; tibial condylar slope, 37.7 ± 6.6 vs 41.3 ± 7.6mm; P= .027). The fibular position and lateral proximal tibial geometry affect the osteotomy configuration and LHFs. A highly positioned fibula was related to a small lateral tibial condyle, which induced a thin proximal fragment. This finding was related to a higher risk of LHFs. Therefore, understanding the fibular height and lateral proximal tibial geometry may be helpful for the prediction of the osteotomy configuration and development of LHFs. Level III, case-control study.

Distribution of the Force in the Knee Joint during Daily Activities after Open Wedge High Tibial Osteotomy: A Rationale for the Proper Postoperative Management.

The present study was conducted to evaluate the force distribution in knee joint during daily activities after open-wedge high tibial osteotomy (OWHTO). A three-dimensional proximal tibial finite element model (FEM) was created using Mimics software to evaluate computed tomography (CT) scans of the tibia after OWHTO. The anterior and posterior gaps were 7.0 and 12.1 mm, respectively, and the target opening angle was 12 degrees. The loading ratio of the medial and lateral tibial plateaus was 6:4. To evaluate force distribution in the knee joint during activities of daily living (ADLs) after OWHTO, peak von Mises stresses (PVMSs) were analyzed at the plate and posterolateral edge region of osteotomized tibia. ADLs associated with greater knee flexion (sitting 90 degrees, standing 90 degrees, bending 90 degrees, stepping up stairs 60 degrees, and stepping downstairs 30 and 60 degrees) yielded PVMSs ranging from 195.2 to 221.5 MPa at the posterolateral edge region. In particular, stepping downstairs with knee flexion to 60 degrees produced the highest PVMS (221.5 MPa), greater than the yield strength (100-200 MPa). The highest plate PVMS was greater than 300 MPa during ADLs associated with flexion angles of approximately 90 degrees. However, these values did not exceed the yield stress (760.0 MPa). Conclusively, higher force was generated during higher flexion associated with weight-bearing and stepping downstairs produced a high force (even at lower flexion) on the posterolateral area of the tibial plateau. Therefore, a caution should be exercised when engaging in knee flexion of approximately 90 degrees and stepping downstairs in the early postoperative period when patients follow a weight-bearing rehabilitation protocol. However, this study is based on modeling; further translational studies are needed prior to clinical application.

Acute Correction of Varus Knee by Biplanar Medial Opening-Wedge High Tibial Osteotomy and Fixation with TomoFix Plate

Background: Biplanar medial opening wedge high tibial osteotomy (MOWHTO) is a treatment method that allows adequate correction of symptomatic varus knee deformity. However, MOWHTO tends to decrease patellar height and increase the posterior tibial slope, which can affect the knee joint stability. Objective: The aim of this study was to describe the technique of biplanar MOWHTO and fixation by TomoFix plate, as well as to evaluate the accuracy of the planned correction and the postoperative tibial slope. Patients and Methods: This prospective cohort study was conducted on patients who presented with varus knee deformity and underwent biplanar MOWHTO and fixation by TomoFix plate during the period from March 2016 to March 2017. Assessment of patients included pre- and postoperative Knee and function scores, mechanical femorotibial angle (mFTA), posterior tibial slope angle (pTSA), range of motion (ROM) and radiological evaluation of the healing of the osteotomy site. Results: The recruited patients were 13 (8 men and 5 women), with average age 31.7 years old. The knee and functional scores improved from the preoperative mean of 45 and 41 to the postoperative mean of 85 and 72 points, respectively. The average knee flexion was 115 degrees, which at the final follow-up remained unchanged except for one case. The mean preoperative mFTA was 13.5° varus and decreased post-operatively to a mean of 3° valgus. The average postoperative follow-up period was 12 months (10 - 18 M). Conclusion: The biplanar MOWHTO allows preservation of posterior tibial slope while correcting the varus knee adequately.

Biplanar Open-Wedge High Tibial Osteotomy with Locking Plate for Treatment of Osteoarthritic Varus Knee

Aim: To introduce and characterize the modified biplanar opening high tibial osteotomy with rigid fixation to treat unicompartmental knee arthritis with varus deformity in active lifestyle patients. Patients and Method: 48 patients (19 females) with monocompartmental gonarthrosis of the knee combined with varus malalignment, 41 with bilateral affection and 7 cases with unilateral gonarthritis (total 89 knees). Mean age: 53 years (range from 42 to 61 years). They were treated and followed from June 2010 to May 2014 (35 months). Biplanar opening high tibial osteotomy technique was used and fixed by low profile locked T-plate (21 cases) and low profile anatomical proximal tibial plate (27cases). Pre-operative mean varus deformity was 16.5° (9° - 19°). We utilized Lysholm score and Knee Society Score for evaluation of preoperative and follow-up data. Results: The average correction angle was 11.50 ± 2.50° (7° - 19°). Preoperative posterior tibial slope was 8.04° ± 1.30° and at last follow-up 9.15° ± 1.60°, respectively (p = 0.437). The joint space distance increased from 4.05 ± 1.30 mm to 4.83 ± 1.33 mm (p < 0.001). The average time to complete bone union was 14.69 ± 1.5 weeks. There were no cases of delayed union or non-union. No major complications like broken plate, nerve injury, or blood vessel injury occurred. No progression of degenerations developed in the three compartments of the knee at final follow-up. The mean score on the Lysholm-Gillquist knee functional scoring scale was 45.5 ± 21.7 preoperatively, and it improved to 77.0 ± 23.9 (p < 0.001). There was no obvious difference in the range of motion before and after operation. The average knee score improved from 51.19 ± 11.82 to 93.49 ± 5.10. Conclusion: Biplanar opening high tibial osteotomy fixed with locking compression plate gives good results for symptomatic unicompartmental gonarthrosis with genu varum. Also this technique can be applied for medial compartment degeneration of the knee without deformity with good functional outcomes.

The Learning Curve for Biplane Medial Open Wedge High Tibial Osteotomy in 100 Consecutive Cases Assessed Using the Cumulative Summation Method.

PurposeThe purpose of this study was to investigate whether surgical experience could improve surgical competency in medial open wedge high tibial osteotomy (MOWHTO).Materials and MethodsOne hundred consecutive cases of MOWHTO were performed with preoperative planning using the Miniaci method. Surgical errors were defined as under- or overcorrection, excessive posterior slope change, or the presence of a lateral hinge fracture. Each of these treatment failures was separately evaluated using the cumulative summation test for learning curve (LC-CUSUM).ResultsThe LC-CUSUM showed competency in prevention of undercorrection, excessive posterior slope change, and lateral hinge fracture after 27, 47, and 42 procedures, respectively. However, the LC-CUSUM did not signal achievement of competency in prevention of overcorrection after 100 procedures. Furthermore, the failure rate for overcorrection showed an increasing tendency as surgical experience increased.ConclusionsSurgical experience may improve the surgeon’s competency in prevention of undercorrection, excessive posterior slope change, and lateral hinge fracture. However, it may not help reduce the incidence of overcorrection even after performance of 100 cases of MOWHTO over a period of 6 years.