Medial opening wedge high tibial osteotomy: A prospective cohort study of gait, radiographic, and patient-reported outcomes

Compensatory mechanisms for proximal & distal joint alignment & gait in varus knee osteoarthritis treated with high tibial osteotomy: A systematic review

Background

Varus deformity is common in medial compartment knee osteoarthritis (OA). This coronal plane malalignment is compensated for by static and dynamic adjustments in the position of the adjacent joints, principally in the hindfoot & ankle. Varus knee OA can be treated in selected patients with high tibial osteotomy (HTO) and stabilised with a fixed angle plate or circular frame, which may reverse these compensatory adjustments. The aim of this systematic review is to determine the evidence available for static and dynamic compensations with the main objectives being to improve deformity planning and optimise patient outcomes.

Method

A systematic review with meta-analysis was designed using the PRISMA template to meet the research aims & objectives.

Results

A total of 1006 patients (1020 knees) with acombined mean age of 54.5 years, female:male ratio of 0.9:1 were extracted from 19 included studies. The methodologies of the majority of studies were at high risk of bias according to the Newcastle-Ottawa Scale demonstrating significant heterogeneity. The combined mean change in the HKA axis was 7.7°; MPTA 7.4°; TT, 0.21°; TI 4.56° & AJLO 4° valgus. Preoperative hindfoot valgus compensation reverts towards neutral post-HTO. There is limited evidence available for a direct relationship between static alignment and dynamic gait parameters.

Conclusions

An inverse relationship between ankle and hindfoot alignment in varus deformity of the knee forms the basis of this compensation theory. In cases with a stiff hindfoot which may not revert postoperatively, the reconstructive orthopaedic surgeon may consider angulation with translation HTO, in order to optimise joint alignment and minimise transference of symptoms to the foot and ankle.

Is single-stage bilateral medial opening wedge high tibial osteotomy advisable?

PURPOSE

To validate the safety and clinical results of single-stage bilateral versus unilateral medial opening wedge high tibial osteotomy (HTO).

METHODS

A propensity-matched cohort study was performed from March 2020 to March 2021 in our medical center. Data were prospectively collected. Including 34 patients who underwent single-stage bilateral medial opening HTO(SSBHTO), and 68 cases in the unilateral group. Propensity-matched ration was 2:1 based on age, sex, and body mass index using R software. Comparisons of the length of hospital stay, operative time, blood loss, postoperative adverse events, 90-day readmission rate, conversion to TKA rate, self-reported VAS and WOMAC scores were made to investigate the safety and clinical results of bilateral HTO.

RESULTS

The mean length of hospital stay was 7.36 ± 2.23 days for SSBHTO and 7 days (IQR, 3 days; range, 4 to 23 days) for the unilateral group (P = 0.219). The mean operative time was 144 ± 47 min for bilateral HTO and 105(37.5) mins for a unilateral OWHTO (P < 0.001). The mean blood loss was 150(100) ml for SSBHTO and 100(50) ml for unilateral OWHTO (P < 0.001). There were no significant difference of the adverse events and 90-day readmission rate between two groups. No failed HTO or conversion to knee arthroplasty were observed at the end of follow-up. VAS, pain, stiffness, and functional scores of the WOMAC scale were essentially comparable of two groups one year after surgery (P > 0.05).

CONCLUSIONS

A single-stage bilateral medial opening wedge high tibial osteotomy is advisable for patients with knee osteoarthritis. Patients benefit from avoiding secondary anesthesia, postoperative complications, and substantial cost savings.

LEVEL OF EVIDENCE

Therapeutic Level III.

Development of an automatic surgical planning system for high tibial osteotomy using artificial intelligence

BACKGROUND

This study proposed an automatic surgical planning system for high tibial osteotomy (HTO) using deep learning-based artificial intelligence and validated its accuracy. The system simulates osteotomy and measures lower-limb alignment parameters in pre- and post-osteotomy simulations.

METHODS

A total of 107 whole-leg standing radiographs were obtained from 107 patients who underwent HTO. First, the system detected anatomical landmarks on radiographs. Then, it simulated osteotomy and automatically measured five parameters in pre- and post-osteotomy simulation (hip knee angle [HKA], weight-bearing line ratio [WBL ratio], mechanical lateral distal femoral angle [mLDFA], mechanical medial proximal tibial angle [mMPTA], and mechanical lateral distal tibial angle [mLDTA]). The accuracy of the measured parameters was validated by comparing them with the ground truth (GT) values given by two orthopaedic surgeons.

RESULTS

All absolute errors of the system were within 1.5° or 1.5%. All inter-rater correlation confidence (ICC) values between the system and GT showed good reliability (>0.80). Excellent reliability was observed in the HKA (0.99) and WBL ratios (>0.99) for the pre-osteotomy simulation. The intra-rater difference of the system exhibited excellent reliability with an ICC value of 1.00 for all lower-limb alignment parameters in pre- and post-osteotomy simulations. In addition, the measurement time per radiograph (0.24 s) was considerably shorter than that of an orthopaedic surgeon (118 s).

CONCLUSION

The proposed system is practically applicable because it can measure lower-limb alignment parameters accurately and quickly in pre- and post-osteotomy simulations. The system has potential applications in surgical planning systems.

Infection in osteotomy around the knee: Incidence, management and outcomes in a high-volume case series

PURPOSE

Current evidence around the management of osteotomy-related infection is insufficient to robustly underpin the expert statements formulated by a recent European consensus statement. We present a review of a large case series in a high-volume osteotomy practice to contribute to the understanding of the incidence, management and outcome of infection in this subspecialty area.

METHODS

Analyses of two prospectively collected databases for all osteotomy around the knee and infections related to osteotomy were performed, along with a review of hospital readmission data to capture all osteotomy-related infections. Clinical notes were reviewed to assess patient demographics, incidence of infection, how infection was managed and clinical outcome.

RESULTS

In a series of 822 osteotomies in 755 patients, there were 21 (2.8%) cases of suspected infection. Twelve (1.6%) were contemporaneously deemed 'superficial' and nine confirmed 'deep' infections (1.2%). Deep infections were all successfully managed with wound debridement, with or without plate removal, depending on union and time from initial surgery. One of these infections was noted during a revision procedure, but no revision was carried out as a direct result of infection, no external fixation was required and no infected nonunions were experienced.

CONCLUSION

All of the cases in this series were managed successfully with debridement ± removal of the plate, without the need for revision or external fixation. Any potential signs of infection around an osteotomy, especially in the case of medial high tibial osteotomy, should raise awareness for deep infection and the need for further surgery due to the limited overlying soft tissue cover. This evidence supports the recent European Society of Sports Traumatology, Knee Surgery and Arthroscopy algorithm.

LEVEL OF EVIDENCE

Level IV, case series.

Medial opening wedge high tibial osteotomy for the treatment of medial unicompartmental knee osteoarthritis: A state-of-the-art review

Medial unicompartmental knee osteoarthritis is a common condition that is frequently associated with significant pain and dysfunction. Medial opening wedge high tibial osteotomy (MOWHTO) offers a unique opportunity to preserve the knee joint and potentially alter the course of the degenerative process. Recent advances in this field of surgery have enabled surgeons to perform a MOWHTO in a safe, reliable and reproducible manner. This state-of-the-art review highlights the most important advances in the field of MOWHTO. Key concepts related to patient selection, pre-operative planning, surgical accuracy and patient outcome are considered. The importance of an individualized approach is emphasized and its influence on the future direction of the procedure is discussed.

Visualization of lateral meniscus extrusion during gait using dynamic ultrasonographic evaluation

PURPOSE

Medial meniscus extrusion is one of the risk factors for knee osteoarthritis (OA). However, lateral meniscus extrusion has not been discussed, and detailed information remains unknown. In particular, the lateral meniscus has high mobility and is expected to be difficult to evaluate in terms of its behavior under static conditions. Dynamic ultrasonographic evaluation was introduced to detect the dynamic behavior of the meniscus during walking. In this study, we aimed to investigate the behavior of the lateral meniscus during walking using dynamic ultrasonographic evaluation.

METHODS

Sixteen participants with knee OA were recruited in this study. The change of lateral meniscus extrusion during walking was recorded using ultrasonography. Medial and lateral meniscal extrusion during the stance phase was measured, and meniscal mobility was defined as the difference in meniscal extrusion between minimum and maximum values (mm), medial meniscal extrusion (∆MME), and lateral meniscal extrusion (∆LME), respectively. The walking cycle and gait forms of lateral thrust were also evaluated using three-dimensional motion analysis systems and analyzed in terms of the correlation with ∆MME and ∆LME.

RESULTS

The lateral meniscus was depicted in the articular plane, and extrusion decreased during the stance phase of the gait cycle. The ∆LME was significantly higher than the ∆MME (p < 0.01). There was a significant positive correlation between ∆LME and lateral thrust (r = 0.62, p < 0.05).

CONCLUSIONS

We found that dynamic ultrasonographic evaluation can be used to visualize lateral meniscus extrusion during walking, and that its behavior is correlated to the degree of lateral thrust.

Association of Medial Meniscal Volume With Decreased Joint Space Width After Medial Opening-Wedge High Tibial Osteotomy

Background

Medial opening-wedge high tibial osteotomy (MOWHTO) reduces contact stress by altering the weightbearing axis from the medial to the lateral compartment, relieves knee pain, and slows the progression of osteoarthritis.

Purpose/Hypothesis

To evaluate whether the volume of the medial meniscus affects outcomes after MOWHTO. It was hypothesized that reduced medial meniscal volume would be associated with worse midterm clinical and radiographic outcomes.

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 59 patients who underwent MOWHTO and had ≥4 years of follow-up data. The mean follow-up period was 66.5 ± 15.1 months (range, 48-110 months). The cohort was classified into 3 groups according to the status of the medial meniscus on arthroscopic examination before osteotomy: no meniscal tear, degenerative tear leading to partial meniscectomy, and degenerative tear leading to subtotal meniscectomy. The Hospital for Special Surgery score and Knee Society objective and functional scores were compared among the groups at 2 time points (preoperative and latest follow-up), and the medial joint space width (JSW) was compared among the groups at 3 time points (preoperative, 1 year postoperative, and latest follow-up).

Results

Overall, 9 patients had no meniscal tear, 20 patients underwent partial meniscectomy, and 30 patients underwent subtotal meniscectomy. The clinical scores improved significantly from preoperatively to the latest follow-up (P ≤ .001 for all), with no significant difference among the groups. Post hoc analysis indicated that at the latest follow-up, JSW was significantly lower in the subtotal meniscectomy group compared with the no-tear group on both 45° of flexion posterior-anterior (2.5 ± 1.3 vs 3.9 ± 1.8 mm; P = .004) and anterior-posterior (3.4 ± 1.1 vs 4.5 ± 0.9 mm; P = .011) radiographs.

Conclusion

Subtotal meniscectomy of the medial meniscus performed during arthroscopic examination with MOWHTO was associated with decreased JSW at midterm follow-up. Efforts should be made to preserve the medial meniscus as much as possible during MOWHTO.

Hip abduction angle after open-wedge high tibial osteotomy is associated with the timed up & go test and recurrence of varus alignment

The aim of this study is to investigate the association between the hip abduction angle (HAA) and lower limb alignment as well as the clinical assessments in open-wedge high tibial osteotomy (OWHTO) patients. A total of 90 patients who underwent OWHTO were included. The demographic characteristics and clinical assessments (the Visual Analogue Scale for activities of daily living, the Japanese knee osteoarthritis measure, the Knee injury and Osteoarthritis Outcome Score, the Knee Society score, the Timed Up & Go (TUG) test, the single standing (SLS) test and muscle strength) were recorded. The patients were divided into two groups according to the HAA at 1 month after operation: the HAA (-) group (HAA < 0°) and the HAA (+) group (HAA ≥ 0°). Clinical scores except for the SLS test and radiographic parameters except for the posterior tibia slope (PTS), lateral distal femoral angle (LDFA) and lateral distal tibial angle (LDTA) were significantly improved at 2 years postoperatively. Regarding the two groups, scores on the TUG test in the HAA (-) group were significantly lower than those in the HAA (+) group (p = 0.011). The hip-knee-ankle angle (HKA), weight bearing line (WBLR) and knee joint line obliquity (KJLO) in the HAA (-) group were significantly higher than those in the HAA (+) group (p < 0.001, 0.001 and p = 0.025). In contrast, the LDFA in the HAA (-) group were significantly lower than those in the HAA (+) group (p < 0.001). The TUG test and the LDFA were weakly positively correlated with the HAA (r = 0.34, 0.42, p < 0.001 and 0.001). In contrast, the HKA, WBLR and KJLO had a weak negative correlation with the HAA (r = - 0.43, - 0.38 and - 0.37, p < 0.001, 0.001 and 0.001). This study showed the postoperative HAA was significantly associated with the TUG test and the HKA, WBLR, LDFA, and KJLO. A higher postoperative HAA might induce varus recurrence and poor outcomes of the gait parameter.

Using multivariate nonlinear mixed-effects model to investigate factors influencing symptom improvement after high tibial osteotomy in combination with bone marrow concentrate injection for medial compartment knee osteoarthritis: a prospective, open-label study

PURPOSE

To investigate the effects of various demographic, structural, radiographic, and clinical factors on the prognosis of patients with medial compartmental knee osteoarthritis with varus deformity undergoing medial opening wedge high tibial osteotomy (HTO) in combination with bone marrow concentrate (BMC) injection.

METHODS

In this prospective study, 20 patients underwent medial opening wedge HTO in combination with BMC injection with 12 months of follow-up. The structural and radiographic outcomes were evaluated by femorotibial angle and posterior tibial slope angle. The clinical outcomes were evaluated by visual analogue scale (VAS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and The Knee injury and Osteoarthritis Outcome Score (KOOS). Multivariate nonlinear mixed-effects models with asymptotic regressions were used to model the trajectory of symptom improvement.

RESULTS

Medial opening wedge HTO in combination with BMC corrected the malalignment of the knee and led to significant symptom relief. The improvement of clinical symptoms reached a plateau 6 months after the surgery. Greater symptom severity at baseline and lower Kellgren-Lawrance (KL) grades were correlated with better post-operative clinical outcomes. Body-Mass-Index (BMI), femorotibial angle, age, and sex may also play a role in influencing the extent of symptom relief.

CONCLUSION

Symptom severity at baseline is important for prognosis prediction. In clinical practice, we suggest that the evaluation of clinical features and functional status of the patients be more emphasised.

Clinical Outcome after Medial Open-Wedge High Tibial Osteotomy: Comparison of Two Angular Stable Locking Plates—TomoFix™ versus LOQTEQ® HTO Plate

This study evaluated bony healing and clinical results after medial open-wedge HTO to compare the outcome of the LOQTEQ® HTO plate and the TomoFix™ internal plate fixator. A prospective, non-randomised, comparative study was undertaken. The same surgical technique for the medial open-wedge HTO was used in two treatment groups. In Group 1, the TomoFix™ implant was used for osteosynthesis, and, in Group 2, the LOQTEQ® HTO plate was used. All patients were examined before surgery (T0) and then at 12 months (T1) and at 24 months (T2) postoperatively. The primary outcome measure was the KOOS pain subscore. The secondary outcome criteria were other KOOS subscales, the Tegner score, radiological healing (RUST), and incision length. The KOOS pain subscale and the other KOOS subscores increased significantly in both groups from T0 to T1 and T2 without a significant group difference at each timepoint. The activity measured with the Tegner scale increased significantly from T0 to T2 without a significant group difference. No radiological signs of implant failure were observed in any case at the one-year X-ray, and no patient fulfilled the criteria for non-union. There was no significant difference in the frequency of adverse effects between the two treatment groups. The length of the incision was significantly shorter in the LOQTEQ® HTO group than in the TomoFix™ group. The results of this study show that patient-related outcome scores (KOOS, Tegner) increased after medial open-wedge HTO. There was no difference in clinical outcome or radiological healing between the treatment groups. Both plates are suitable for the osteosynthesis of open-wedge HTO.

Higher Association of Pelvis-Knee-Ankle Angle Compared With Hip-Knee-Ankle Angle With Knee Adduction Moment and Patient-Reported Outcomes After High Tibial Osteotomy

BACKGROUND

High tibial osteotomy (HTO) reduces the load distribution of the medial compartment by modifying leg alignment. Knee adduction moment (KAM), a surrogate measure of dynamic loading in the knee joint, decreases after HTO. However, leg alignment does not fully account for KAM.

PURPOSE

To assess the association between the pelvis-knee-ankle angle (PKA), a novel radiographic parameter reflecting leg alignment and pelvic width, and KAM and patient-reported outcomes after HTO.

STUDY DESIGN

Cross sectional study; Level of evidence, 3.

METHODS

PKA is the angle between the line from the midpoint of the anterior superior iliac spine to the center of the knee joint and the mechanical axis of the tibia. In this study, 54 patients with medial compartment knee osteoarthritis and varus alignment who underwent 3-dimensional gait analysis preoperatively and 2 years after medial open-wedge HTO were evaluated. The primary outcomes were hip-knee-ankle angle (HKA), PKA, KAM peaks, and Knee Society Score (KSS). Single and multivariate regression analysis including PKA and KAM peaks as well as other demographic and radiologic factors was performed.

RESULTS

HKA was weakly correlated with the first peak KAM (r = -0.33; P < .01) and second peak KAM (r = -0.27; P = .01) before HTO, but not significantly correlated after HTO. PKA was moderately correlated with the first peak KAM (r = 0.45; P < .01) and second peak KAM (r = 0.45; P < .01) before HTO and with the first peak KAM (r = 0.51; P < .01) and second peak KAM (r = 0.56; P < .01) after HTO. Multivariate linear regression revealed that postoperative PKA was still associated with the KAM peaks after HTO. Only postoperative PKA was correlated with the KSS satisfaction subscale (r = -0.30; P = .03).

CONCLUSION

Although HKA was not correlated with KAM peaks after HTO, PKA was significantly correlated with KAM peaks in patients with varus knee osteoarthritis after HTO.

High tibial osteotomy effectively redistributes compressive knee loads during walking

The objectives of this study were to estimate pre- and postoperative lower limb kinematics and kinetics and knee intra-articular forces during gait using musculoskeletal modeling in a cohort of patients with knee osteoarthritis (OA) undergoing high tibial osteotomy (HTO), compare these to controls, and determine correlations between changes in these parameters and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscores after HTO. Sixteen patients with isolated, symptomatic medial compartment knee OA completed pre- and postoperative gait analysis (mean follow-up time: 8.6 months). Sixteen age- and sex-matched asymptomatic volunteers participated as controls. Musculoskeletal modeling was used to evaluate lower limb joint moments and knee contact forces during gait. While HTO had limited influence on sagittal plane kinematics and moments, significant changes in the load distribution at the knee after HTO were observed with a lower postoperative compressive load on the medial compartment during midstance and a higher compressive load on the lateral compartment during early and late stance. Moreover, the lateral shear force in midstance was significantly lower after HTO. Changes in the external knee adduction moment (KAM) did not always coincide with reductions in the knee compressive force in the medial compartment. Biomechanical changes did not correlate with improvements in KOOS subscores. Hence, HTO effectively unloaded the medial compartment by redistributing part of the overall compressive force to the lateral compartment during gait with limited influence on gait function. The KAM may not adequately describe compartmental load magnitude or changes induced by interventions at the compartment level. Clinical trial registration: ClinicalTrials. gov Identifier-NCT02622204. Clinical significance: This study provides important evidence for changes in joint level loads after corrective osteotomy as joint preserving surgery and emphasizes the need for additional biomechanical outcomes of such interventions.

Preoperative overweight and obesity do not cause inferior outcomes following open-wedge high tibial osteotomy: A retrospective cohort study of 123 patients

Open-wedge high tibial osteotomy (OWHTO) is effective in treating medial compartment osteoarthritis. The association between body mass index (BMI) and outcomes following OWHTO is being debated. This study compared radiographic and clinical outcomes between patients with preoperative overweight, obesity, and normal BMI following OWHTO for medial compartment osteoarthritis. In total, 123 patients (123 knees) who underwent OWHTO for medial compartment osteoarthritis were enrolled and were divided into normal-BMI (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), and obese (>30 kg/m2) groups based on body mass index. The numeric rating scale for pain, mechanical tibiofemoral angle (mTFA), tibia tilting angle (TTA), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) for function were evaluated preoperatively and at postoperative follow-ups. The improvements of clinical and radiological outcomes in normal-BMI, overweight, and obese groups were not significantly different. The incidence of soft tissue irritation, wound infection, nonunion, and conversion to total knee arthroplasty were not significantly different between groups.The clinical and radiological outcomes in patients with preoperative overweight, obesity, and normal-BMI were not significantly different. Preoperative overweight and obesity thus has no effect on outcomes following OWHTO during the two years follow-up period. These findings cannot be generalized to patients with morbid obesity.

Gait analysis and knee kinematics before, and 6 and 18 months after corrective valgus osteotomy

BACKGROUND

The study objective was to assess clinical outcomes and gait biomechanics in patients after 6 and 18 months after varus deformity (VD) surgical correction at knee joint (KJ).

METHOD

The study included 20 patients with medial osteoarthritis (OA) of the knee of grade 2-3 and a VD of >4°. A total of 21 surgeries were performed on the patients. Full length weight bearing (FLWB) X-ray and KJ assessments were done using the KSS, KOOS and VAS scoring systems were obtained from all the patients. Biomechanical gait parameters were captured using an inertial sensor system at timepoints before, and 6 and 18 months after surgery. Temporal and kinematic parameters of walking were analyzed.

RESULTS

The radiological parameters showed a stable VD correction. According to the KOOS, KS and VAS scores, there was a moderate dynamic improvement in the operated knee function during the study. The biomechanical parameters remained virtually unchanged throughout the entire follow-up period. In the following year, there were some subjective improvements but without any significant changes in gait biomechanics or knee kinematics.

CONCLUSIONS

Thus, the main changes in the joint clinical condition and function occur in the first 6 months after surgery. According to the study data-assessments by VAS, KOOS, and KSS-there was a moderate clinical improvement during the long-term follow-up period, however, the biomechanical changes were minor.

Effect of the Inverted V-Shaped Osteotomy on Patellofemoral Joint and Tibial Morphometry as Compared With the Medial Opening Wedge High Tibial Osteotomy

BACKGROUND

Recent studies have reported that medial opening wedge (OW) high tibial osteotomy (HTO) induces patella baja, resulting in degenerative changes in the patellofemoral joint. We have developed an inverted V-shaped (iV) HTO, which is classified as a neutral wedge osteotomy.

HYPOTHESES

The study hypotheses were as follows: (1) patellar height, posterior tibial slope, and tibial length will not change between pre- and postoperative evaluations after iV-HTO; (2) the lateral shift ratio of the patella and the distance between the tibial tubercle and the trochlear groove may be significantly decreased after iV-HTO.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 191 patients (220 knees) who underwent HTO for medial osteoarthritis were enrolled retrospectively in this study: 107 knees underwent OW-HTO and 113 knees underwent iV-HTO. Clinical and radiological evaluations were performed before and at least 3 years after surgery.

RESULTS

Postoperatively, the mean Caton-Deschamps ratio was significantly decreased (P < .0001) from 0.95 to 0.79 in the OW group, while there were no significant changes in the iV group. The mean posterior tibial slope was significantly increased (P < .0001) from 8.5° to 10.5° in the OW group, while there were no significant differences in the iV group. Although the entire leg length was significantly increased (P < .0003) in both groups after HTO, there were no significant differences in tibial length between the pre- and postoperative periods in the iV group. Regarding the congruity of the patellofemoral joint, the mean lateral shift ratio did not significantly change in the OW group, whereas it was significantly decreased (P = .0012) from 11.5% to 8.8% in the iV group. The mean tibial tubercle-trochlear groove distance was significantly decreased (P < .0001) from 12.8 to 9.7 mm in the iV group, while it was significantly increased in the OW group (P < .0001). Concerning the clinical outcome, the Japanese Orthopaedic Association (JOA) and Lysholm knee scores at final follow-up (OW vs iV: JOA, 91.2 vs 90.1; Lysholm, 92.5 vs 89.0) were significantly increased (P < .0001) as compared with the preoperative values (OW vs iV: JOA, 68.3 vs 66.8; Lysholm, 67.9 vs 61.0).

CONCLUSION

Patellar height, posterior tibial slope, and tibial length did not change after the iV-HTO, while they were significantly changed after the OW-HTO. Although the preoperative degrees of varus knee and patellofemoral osteoarthritis were more severe in the iV group than the OW group, the iV-HTO led to altered patellofemoral joint congruity.

Tibio-Femoral Contact Force Distribution of Knee Before and After Total Knee Arthroplasty: Combined Finite Element and Gait Analysis

Objective

To assess the tibio‐femoral contact forces before and after total knee arthroplasty (TKA) in patients with knee osteoarthritis (KOA) by three‐dimensional (3D) finite element analysis (FEA) models and gait analysis.

Methods

Two hospitalized patients with Kellgren–Lawrence grade IV varus KOA and two healthy subjects were enrolled in this study. Both patients underwent unilateral TKA. FEA models were established based on CT and MR images of the knees of the patients with KOA and healthy subjects. Gait analysis was performed using a three‐dimensional motion capture system with a force plate. Three direction forces at the ankle joints were calculated by inverse dynamic analysis, which provided the load for the FEA models. The total contact forces of the knee joints were also calculated by inverse dynamic analysis to enable comparisons with the results from the FEA models. The total knee contact forces, maximum von Mises stress, and stress distribution of the medial plateau were compared between the patients and healthy subjects. The distributions of the medial plateau force at 2 and 6 months postoperatively were compared with the distributions of the forces preoperatively and those in the healthy subjects.

Results

During static standing, the medial plateau bore the most of the total contact forces in the knees with varus KOA (90.78% for patient 1 and 93.53% for patient 2) compared with 64.75 ± 3.34% of the total force in the healthy knees. At the first and second peaks of the ground reaction force during the stance phase of a gait cycle, the medial plateau bore a much higher percentage of contact forces in patients with KOA (74.78% and 86.48%, respectively, for patient 1; 70.68% and 83.56%, respectively, for patient 2) than healthy subjects (61.06% ± 3.43% at the first peak and 72.09% ± 1.83% at the second peak). Two months after TKA, the percentages of contact forces on the medial tibial plateau were 79.65%–85.19% at the first and second peaks of ground reaction forces during the stance phase of a gait cycle, and the percentages decreased to 53.99% – 68.13% 6 months after TKA.

Conclusion

FEA showed that TKA effectively restored the distribution of tibio‐femoral contact forces during static standing and walking, especially 6 months after the surgery. The changes in the gait were consistent with the changes in the contact force distribution calculated by the FEA model.

Prognostic factors for medial open-wedge high tibial osteotomy with spacer implantation in patients with medial compartmental knee osteoarthritis

Background

To identify medial open-wedge high tibial osteotomy (MOWHTO) prognostic factors with wedge-shaped spacer implantation (spacer-type MOWHTO) for varus medial compartment knee osteoarthritis.

Methods

Patients who underwent spacer-type MOWHTO between August 2018 and September 2019 were prospectively enrolled in this study. Patients were divided into effective group and invalid group based on the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) score one year postoperatively. The variables assessed at baseline and one year postoperatively including age, sex, body mass index (BMI), Kellgren–Lawrence (K–L) grade, hip–knee–ankle angle (HKAA), medial proximal tibial angle (MPTA), posterior tibial slope angle (PTSA), Blackburn–Peel index (BPI), duration of symptoms, and WOMAC score were compared. Prognostic factors were analyzed using logistic regression, and the corresponding odds ratios were also calculated.

Results

A total of 104 patients were enrolled in the study protocol at one year postoperatively. The WOMAC score decreased from 72.39 ± 12.95 at baseline to 20.06 ± 12.96 at one year postoperatively. Univariate analysis revealed that the significant predictors of the WOMAC score were age > 70 years, BMI > 30 kg/m², K–L grade IV, and pre-HKAA > 10° (P < 0.1 for all). Multivariable logistic regression analysis revealed that age > 70 (OR = 4.861) and K–L grade IV (OR = 6.590) were significantly associated with the higher WOMAC score at one year postoperatively.

Conclusions

Spacer-type MOWHTO is an effective treatment for osteoarthritis with varus deformity. The prognostic factors for spacer-type MOWHTO are age and K–L grade.

The Relationships between Coronal Plane Alignments and Patient-Reported Outcomes Following High Tibial Osteotomy: A Systematic Review

OBJECTIVE

This systematic review aimed to determine whether coronal angular corrections correlate with patient reported outcomes following valgus-producing high tibial osteotomy (HTO).

DESIGN

Ovid MEDLINE, Embase, and Web of Science were systematically searched. Studies that reported hip-knee-ankle angles (HKA) or femorotibial angles (FTA), and the Oxford Knee Score (OKS), visual analogue scale (VAS) score, Knee Injury and Osteoarthritis Outcome Score (KOOS), or EQ-5D before and after valgus-producing HTO were eligible. Correlation analyses were performed where appropriate to investigate the relationships between variables. PROSPERO ID: CRD42019135467.

RESULTS

This study included 39 articles including 50 cohorts. VAS was reported in 22 studies, OKS in 9, KOOS in 12 and EQ-5D in 2. The HKA angle was corrected from 7.1° ± 1.7° varus to 2.3° ± 1.7° valgus at final follow-up. The FTA changed from 3.0° ± 2.0° varus to 7.7° ± 1.3° valgus. Outcome scores improved with clinical and statistical significance postoperatively. Spearman correlations for nonparametric data revealed greater changes in knee alignment were moderately associated with larger improvements in VAS scores (r = 0.50). Furthermore, those who experienced greater changes in alignment showed larger improvements in the KOOS Activity and Quality of Life domains (r = 0.72 and r = 0.51, respectively).

CONCLUSION

On average, patients did not achieve the "ideal correction" of 3° to 6° valgus postoperatively. Nevertheless, statistical and clinical improvements in patient-reported outcome measure scores were consistently reported. This suggests that the "ideal correction" may be more flexible than 3° to 6°.

High Tibial Osteotomy: An Update for Radiologists

High tibial osteotomy (HTO) is a surgical procedure to treat symptomatic unicompartmental osteoarthritis (OA) associated with knee malalignment. There has been a recent resurgence of interest in HTO in patients who prefer joint-preserving surgery, as HTO shifts the knee's mechanical axis from the arthritic compartment to a neutral position, thereby reducing knee pain, slowing progression of OA, and delaying the need for a total knee arthroplasty. The ideal candidates for HTO are young, active, nonobese patients with isolated varus deformity of the knee due to medial compartment OA. Radiography is critical in the preoperative evaluation for HTO and can help expand surgical indications to include a wider variety of patients. Radiography is also routinely obtained in postoperative assessment and is typically the first test to suspect complications. This review describes the radiologic aspects of HTO, including preoperative imaging assessment, as well as normal and abnormal postoperative imaging appearances. Surgical techniques and osteotomy fixation devices are described, with a focus on the medial opening wedge approach. Given the growing interest in HTO, radiologists should become familiar with the basics of the procedure and the role of imaging in preoperative and postoperative evaluation.

A Systematic Review on Selected Complications of Open-Wedge High Tibial Osteotomy from Clinical and Biomechanical Perspectives

BACKGROUND

The wedge opened during high tibial osteotomy defines the alignment correction in different body planes and alters soft tissue insertions. Although multiple complications of the surgery can be correlated to this, there is still a lack of consensus on the occurrence of those complications and their cause. The current study is aimed at clarifying this problem using a combined medical and biomechanical perspective.

METHODS

We conducted a systematic review of the literature on selective complications of the surgery correlated with the angles of the opened wedge. Search topics covered tibial slope alteration, patellar height alteration, medial collateral ligament release, and model-based biomechanical simulations related to surgical planning or complications. Findings. The selection process with the defined inclusion/exclusion criteria led to the collection of qualitative and quantitative data from 38 articles. Medial collateral ligament tightness can be a valid complication of this surgery; however, further information about its preoperative condition seems required for better interpreting the results. The posterior tibial slope significantly increases, and the patellar height (using the Blackburne-Peel ratio) significantly decreases in the majority of the selected studies. Model-based biomechanical studies targeting surgical planning are mostly focused on the lower-limb alignment principles and tibiofemoral contact balancing rather than surgical complications. Interpretation. Increased posterior tibial slope, patellar height decrease, and medial collateral ligament tightness can occur due to alterations in different body planes and in soft tissue insertions after wedge opening. This study clarified that information about preoperative alignment in all body planes and soft-tissue conditions should be considered in order to avoid and anticipate these complications and to improve per surgery wedge adaptation. The findings and perspective of this review can contribute to improving the design of future clinical and biomechanical studies.

Knee Joint Line Obliquity Causes Tibiofemoral Subluxation That Alters Contact Areas and Meniscal Loading

BACKGROUND

Little scientific evidence is available regarding the effect of knee joint line obliquity (JLO) before and after coronal realignment osteotomy.

HYPOTHESES

Higher JLO would lead to abnormal relative position of the femur on the tibia, a shift of the joint contact areas, and elevated joint contact pressures.

STUDY DESIGN

Descriptive laboratory study.

METHODS

10 fresh-frozen human cadaveric knees (age, 59 ± 5 years) were axially loaded to 1500 N in a materials testing machine with the joint line tilted 0°, 4°, 8°, and 12° varus ("downhill" medially) and valgus, at 0° and 20° of knee flexion. The mechanical compression axis was aligned to the center of the tibial plateau. Contact pressure and contact area were recorded by pressure sensors inserted between the tibia and femur below the menisci. Changes in relative femoral and tibial position in the coronal plane were obtained by an optical tracking system.

RESULTS

Both medial and lateral JLO caused significant tibiofemoral subluxation and pressure distribution changes. Medial (varus) JLO caused the femur to subluxate medially down the coronal slope of the tibial plateau, and vice versa for lateral (valgus) downslopes (P < .01), giving a 6-mm range of subluxation. The areas of peak pressure moved 12 mm and 8 mm across the medial and lateral condyles, onto the downhill meniscus and the "uphill" tibial spine. Changes in JLO had only small effects on maximum contact pressures.

CONCLUSION

A 4° change of JLO during load bearing caused significant mediolateral tibiofemoral subluxation. The femur slid down the slope of the tibial plateau to abut the tibial eminence and also to rest on the downhill meniscus. This caused large movements of the tibiofemoral contact pressures across each compartment.

CLINICAL RELEVANCE

These results provide important information for understanding the consequences of creating coronal JLO and for clinical practice in terms of osteotomy planning regarding the effect on JLO. This information provides guidance regarding the choice of single- or double-level osteotomy. Excessive JLO alteration may cause abnormal tibiofemoral joint articulation and chondral or meniscal loading.

Comparison of Clinical and Radiological Outcomes Between Upper Fibular Curvature and Non-Curvature with Medial Knee Osteoarthritis Following Proximal Fibular Osteotomy: A Retrospective Cohort Study with Minimum 2-Year Follow-up

Objective

To evaluate and compare the clinical and radiographic outcomes of proximal fibular osteotomy (PFO) in treating medial knee osteoarthritis (KOA) patients with upper fibular curvature and non‐curvature.

Methods

A retrospective cohort study was performed. From January 2016 to January 2017, a total of 51 patients (nine males and 42 females) at a mean age of 63.7 years (range 48–79 years) with medial KOA who underwent PFO procedure at the Third Hospital of Hebei Medical University were included in the study. The patients were divided into the two groups, namely curvature group (28 patients, six males and 22 females, aged 62.6 ± 7.7 years) and non‐curvature group (23 patients, three males and 20 females, aged 64.5 ± 7.6 years). Perioperative parameters and Kellgren‐Lawrence classification were recorded and analyzed in the two groups, respectively. All patients were followed up at 1, 3, 6, and 12 months at the first year of post‐operation, and then every 6 months from the second year of post‐operation. A telephone survey with standard questionnaire survey, including Visual Analog Scale (VAS) score and Hospital for Special Surgery (HSS) scoring system, was used to evaluate postoperative clinical outcomes. Radiological results were assessed using the femorotibial angle (FTA), hip‐knee‐ankle angle (HKA), and settlement value of medial tibial platform (MTP) in the two groups.

Results

The average follow‐up periods of the curvature group and the non‐curvature group were 34.8 ± 6.1 and 33.9 ± 5.4 months, respectively. There were no significant differences between the two groups of demographic data in terms of number of patients, age, body mass index (BMI), gender, KOA side, and Kellgren‐Lawrence classification (P > 0.05). The VAS scores of the curvature group and non‐curvature group were (3.53 ± 1.62 vs 3.68 ± 1.43 at 1 month, 3.46 ± 0.79 vs 3.57 ± 0.66 at 3 months, and 2.43 ± 0.88 vs 2.83 ± 0.94 at 6 months, both P > 0.05), while significant differences were found from 12 months post‐operation (1.54 ± 0.72 vs 2.03 ± 0.85 at 12 months, and 1.04 ± 0.69 vs 1.74 ± 0.75 at 24 months, both P < 0.05). The HSS scores of the curvature group and non‐curvature group were (79.67 ± 5.14 vs 78.25 ± 6.37 at 1 month, 84.65 ± 3.76 vs 83.18 ± 3.64 at 3 months, and 86.27 ± 3.13 vs 85.49 ± 3.25 at 6 months, both P > 0.05), while significant differences were found from 12 months post‐operation (90.64 ± 4.32 vs 87.71 ± 5.63 at 12 months, and 92.93 ± 2.07 vs 90.06 ± 2.08 at 24 months, both P < 0.05). In addition, the FTA and settlement value of the curvature group were lower than the non‐curvature group (177.18 ± 1.52 vs 178.35 ± 1.86, and 5.29 ± 1.74 vs 6.49 ± 2.09, both P < 0.05) while the HKA were higher than the non‐curvature group (175.32 ± 2.34 vs 173.83 ± 2.64, P < 0.05) at the final follow‐up.

Conclusions

Medial KOA patients with upper fibular curvature is an optimal surgical indication for PFO surgery, with the advantages of pain relief, better functional recovery, and alignment correction.

Changes in the Contact Stress Distribution Pattern of the Patellofemoral Joint After Medial Open-Wedge High Tibial Osteotomy: An Evaluation Using Computed Tomography Osteoabsorptiometry

BACKGROUND

Medial open-wedge high tibial osteotomy (OWHTO) theoretically causes distalization and lateralization of the tibial tuberosity and the patella.

PURPOSE/HYPOTHESIS

The purpose of the study was to identify any changes in the stress distribution of subchondral bone density across the patellofemoral (PF) joint before and after OWHTO through the use of computed tomography (CT) osteoabsorptiometry. We hypothesized that OWHTO would alter the distribution of contact stress in the PF joint.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 17 patients (17 knees) who underwent OWHTO were enrolled in this study between September 2013 and September 2015. All patients underwent radiologic examination preoperatively and at 1 year postoperatively, and the distribution patterns of subchondral bone density through the articular surface of the femoral trochlea and patella were assessed preoperatively and >1 year postoperatively using CT osteoabsorptiometry. The quantitative analysis of the obtained mapping data focused on location of the high-density area (HDA) through the articular surface of the PF joint. The percentage of HDA at each divided region of the articular surface of the femoral trochlea and the patella was calculated.

RESULTS

In the radiologic evaluation, the Blackburne-Peel ratio was significantly reduced (P < .001) after surgery, and the tilting angle of the patella was significantly decreased (P < .001). On CT evaluation, the percentage of HDA in the lateral notch and lateral trochlea of the femur and in the medial portion of the lateral facet of the patella increased significantly after OWHTO surgery (P ≤ .038).

CONCLUSION

OWHTO significantly increased the stress distribution pattern of the lateral trochlea of the femur and the medial portion of the lateral facet of the patella. The procedure significantly lowered the patellar height and significantly decreased the patellar tilting angle after surgery.

Total knee replacement after high tibial osteotomy: time-to-event analysis and predictors

BACKGROUND

An important aim of high tibial osteotomy (HTO) is to prevent or delay the need for total knee replacement (TKR). We sought to estimate the frequency and timing of conversion from HTO to TKR and the factors associated with it.

METHODS

We prospectively evaluated patients with osteoarthritis (OA) of the knee who underwent medial opening wedge HTO from 2002 to 2014 and analyzed the cumulative incidence of TKR in July 2019. The presence or absence of TKR on the HTO limb was identified from the orthopedic surgery reports and knee radiographs contained in the electronic medical records for each patient at London Health Sciences Centre. We used cumulative incidence curves to evaluate the primary outcome of time to TKR. We used multivariable Cox proportional hazards analysis to assess potential preoperative predictors including radiographic disease severity, malalignment, correction size, pain, sex, age, body mass index (BMI) and year of surgery.

RESULTS

Among 556 patients who underwent 643 HTO procedures, the cumulative incidence of TKR was 5% (95% confidence interval [CI] 3%-7%) at 5 years and 21% (95% CI 17%-26%) at 10 years. With the Cox proportional hazards multivariable model, the following preoperative factors were significantly associated with an increased rate of conversion: radiographic OA severity (adjusted hazard ratio [HR] 1.96, 95% CI 1.12-3.45), pain (adjusted HR 0.85, 95% CI 0.75-0.96)], female sex (adjusted HR 1.67, 95% CI 1.08-2.58), age (adjusted HR 1.50 per 10 yr, 95% CI 1.17-1.93) and BMI (adjusted HR 1.31 per 5 kng/m2, 95% CI 1.12-1.53).

INTERPRETATION

We found that 79% of knees did not undergo TKR within 10 years after undergoing medial opening wedge HTO. The strongest predictor of conversion to TKR is greater radiographic disease at the time of HTO.

Combination of Cylindrical Autologous Bone Grafting Technique With a Metallic Block Insertion in Open-Wedge High Tibial Osteotomy

Open-wedge high tibial osteotomy (OW-HTO) is an effective surgical intervention for medial-compartment knee osteoarthritis. However, the osteotomized gap might be a disadvantage in OW-HTO because it can cause problems such as delayed bone union or loss of correction. These issues can be minimized by using autologous bone graft in the osteotomized gap, which is known to be the fastest and most clinically satisfactory gap filler. The primary mechanical stability of the osteotomy site in OW-HTO is essential for early weight bearing after surgery. Therefore, we introduce the combination of a cylindrical autologous bone grafting technique and a metallic block insertion for faster bone union and better primary stability of the site in OW-HTO. We expect that the described procedure will enable early postoperative weight bearing and, thereby, allow an early return to normal function.

Change in intersegmental foot and ankle motion after a high tibial osteotomy in genu varum patients

High tibial osteotomy (HTO) is a well-established treatment for medial compartment knee osteoarthritis (OA), which shifts the weight-bearing axis from the medial to the lateral side of the knee. As the adjacent ankle joint may be directly affected by the change in biomechanics, this study aimed to evaluate the change in the intersegmental foot and ankle motion after HTO in patients with genu varum. The study included 24 patients who underwent HTO, and 48 older healthy participants as a control group. Segmental foot kinematics were evaluated using a 3D multisegment foot model, and gait data of temporal and spatial parameters were obtained. After HTO, normalized stride length significantly increased with a tendency for increases in gait speed. In hallux kinematics relative to the forefoot, the sagittal motions of both the patients and the control group were similar throughout the majority of the gait cycle. In forefoot kinematics relative to the hindfoot, the pre-HTO state revealed significant pronation throughout the gait cycle, while the post-HTO state showed a similar position and motion to the control group. In hindfoot kinematics relative to the tibia, coronal motions of the pre-HTO state showed supination throughout the gait cycle, while supination during the stance phase decreased after HTO. Genu varum patients with medial compartment knee OA showed different gait parameters and intersegmental motion during gait when compared with age- and gender-matched controls. The effect of HTO was demonstrated by the normalization of midfoot compensation in patients with genu varum.

Outcome after treatment of osteoarthritis with open-wedge high-tibial osteotomy with a plate: 2-year results of a Japanese cohort study

PURPOSE

This prospective multicenter study evaluated patient reported outcomes (PROs) in individuals undergoing medial open-wedge high-tibial osteotomy (OWHTO) with plate stabilization compared to conservative care or no treatment.

METHODS

One hundred eighteen of 148 patients older than 40 years were elected for OWHTO with plate treatment. Thirty patients declined surgery and were followed as a conservative group. The primary outcome measure was the Knee Injury and Osteoarthritis Outcome Score (KOOS) at 2 years. Secondary measures included Oxford knee score, Western Ontario and McMaster Universities osteoarthritis index, range of motion (ROM), joint space width (JSW), femorotibial angle (FTA), and weight-bearing line ratio (WBLR).

RESULTS

Patient enrollment and baseline characteristics were heterogeneously distributed and led to group characteristics that were not comparable. Therefore, the comparison of the KOOS between the groups showing no differences must be treated with caution. In the OWHTO plate group, all PROs and the ROM significantly improved between baseline and 2-year follow-up. JSW remained stable in the OWHTO group. The FTA and WBLR significantly changed from a mean of 179.3 (95% confidence interval (CI): 178.7, 179.9) to 169.8 (95% CI: 169.2, 170.5) and from 23.1 (95% CI: 20.7, 25.5) to 62.4 (95% CI 59.0, 65.8), respectively. Treatment failure with conversion to total knee arthroplasty occurred in 1% of the OWHTO group; and in the conservative group, 10% converted to HTO or knee arthroplasty.

CONCLUSIONS

OWHTO with plate leads to significant improvement of PROs and function 2 years after intervention and demonstrates reliable mechanical axis correction with subsequent shift of weight-bearing.

Varus alignment of the proximal tibia is associated with structural progression in early to moderate varus osteoarthritis of the knee

PURPOSE

Lower limb malalignment is a strong predictor of progression in knee osteoarthritis. The purpose of this study is to identify the individual alignment variables that predict progression in early to moderate osteoarthritis of the knee.

METHOD

A longitudinal cohort study using data from the Osteoarthritis Initiative. In total, 955 individuals (1329 knees) with early to moderate osteoarthritis (Kellgren-Lawrence grade 1, 2 or 3) were identified. All subjects had full-limb radiographs analysed using the Osteotomy module within Medicad^® Classic (Hectec GMBH) to give a series of individual alignment variables relevant to the coronal alignment of the lower limb. Logistic regression models, with generalised estimating equations were used to identify which of these individual alignment variables predict symptom worsening (WOMAC score > 9 points) and or structural progression (joint space narrowing progression in the medial compartment > 0.7mm) over 24 months.

RESULTS

Individual alignment variable were associated with both valgus and varus alignment (mechanical Lateral Distal Femoral Angle, Medial Proximal Tibial Angle and mechanical Lateral Distal Tibial Angle). Only the Medial Proximal Tibial Angle was significantly associated with structural progression and none of the variables was associated with symptom progression. The odds of joint space narrowing progression in the medial compartment occurring at 24 months increased by 21% for every one degree decrease (more varus) in Medial Proximal Tibial Angle (p < 0.001) CONCLUSIONS: Our results suggest that the risk of structural progression in the medial compartment is associated with greater varus alignment of the proximal tibia.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Risk factors for pain and functional impairment in people with knee and hip osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

To identify risk factors for pain and functional deterioration in people with knee and hip osteoarthritis (OA) to form the basis of a future 'stratification tool' for OA development or progression.

DESIGN

Systematic review and meta-analysis.

METHODS

An electronic search of the literature databases, Medline, Embase, CINAHL, and Web of Science (1990-February 2020), was conducted. Studies that identified risk factors for pain and functional deterioration to knee and hip OA were included. Where data and study heterogeneity permitted, meta-analyses presenting mean difference (MD) and ORs with corresponding 95% CIs were undertaken. Where this was not possible, a narrative analysis was undertaken. The Downs & Black tool assessed methodological quality of selected studies before data extraction. Pooled analysis outcomes were assessed and reported using the Grading of Reccomendation, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

82 studies (41 810 participants) were included. On meta-analysis: there was moderate quality evidence that knee OA pain was associated with factors including: Kellgren and Lawrence≥2 (MD: 2.04, 95% CI 1.48 to 2.81; p<0.01), increasing age (MD: 1.46, 95% CI 0.26 to 2.66; p=0.02) and whole-organ MRI scoring method (WORMS) knee effusion score ≥1 (OR: 1.35, 95% CI 0.99 to 1.83; p=0.05). On narrative analysis: knee OA pain was associated with factors including WORMS meniscal damage ≥1 (OR: 1.83). Predictors of joint pain in hip OA were large acetabular bone marrow lesions (BML; OR: 5.23), chronic widespread pain (OR: 5.02) and large hip BMLs (OR: 4.43).

CONCLUSIONS

Our study identified risk factors for clinical pain in OA by imaging measures that can assist in predicting and stratifying people with knee/hip OA. A 'stratification tool' combining verified risk factors that we have identified would allow selective stratification based on pain and structural outcomes in OA.

PROSPERO REGISTRATION NUMBER

CRD42018117643.

Distal Tibial Tuberosity Focal Dome Osteotomy Combined With Intra-Articular Condylar Osteotomy (Focal Dome Condylar Osteotomy) for Medial Osteoarthritis of the Knee Joint

High tibial osteotomy for medial-compartment knee osteoarthritis (OA) is an established biological knee reconstruction surgical procedure. In open- and closed-wedge high tibial osteotomy, the angulation correction axes are away from the center of rotation and angulation. This results in translation deformity, which alters the orientation of the adjacent joint and the length of the limb. In the present study, we combined the distal tibial tuberosity focal dome osteotomy centered on the center of rotation and angulation with the longitudinal condylar osteotomy (focal dome condylar osteotomy) for knee OA. The advantages of this procedure are as follows: physiological orientation of adjacent joint is achieved; limb length is maintained; joint stabilization in the coronal plane is achieved; patella infra is prevented; sufficient bone contact between the medial and posterior cortex is achieved; early weight-bearing walking is possible; and fibular osteotomy is not required. This study describes the details of the surgical procedure, including our compass cutter for accurate dome osteotomy and the postoperative rehabilitation program for patients with knee OA and moderate-to-severe varus deformity.

Reliability and validity of knee angles and moments in patients with osteoarthritis using a treadmill-based gait analysis system

BACKGROUND

Although commonly used to study knee osteoarthritis (OA), relatively little is known about the reliability and validity of three-dimensional (3D) gait biomechanics derived from treadmill-based systems.

RESEARCH QUESTION

Using a treadmill-based gait analysis system, our objectives were to: 1) estimate the test-retest reliability of frontal and sagittal plane knee angles and moments in knee OA patients; 2) examine concurrent validity by estimating the associations between treadmill-based and overground (gold standard) measures; and 3) examine known-groups validity by comparing measures between knee OA patients and matched healthy controls.

METHODS

34 patients and 16 controls completed 3D gait analyses using treadmill-based and overground systems. Treadmill walking speed was matched to self-selected overground speed. Marker set, knee angle and moment calculations were consistent for both systems. Patients completed a second test session using the treadmill-based system <24 h later but within 1 week of the first test session. Variables calculated from knee angle and moment gait waveforms during stance were evaluated using Bland and Altman plots, Intraclass Correlation Coefficients (ICC), Pearson correlations (r) and t-tests.

RESULTS

Visual inspection of the Bland and Altman plots did not reveal any systematic differences between test and retest sessions; however, limits of agreement (LoA) were larger for the sagittal plane than the frontal plane. Mean differences between sessions for knee angles were <0.25 degrees and <0.18 %BW*ht for knee moments. ICCs ranged from 0.57-to-0.93 for test-retest reliability. Pearson correlations between treadmill and overground systems ranged from 0.56-to-0.97. Although highly associated, there were substantial differences in the moments, emphasizing they cannot be used interchangeably. Patients had greater first peak knee adduction moments (KAM) than controls [mean difference (95 %CI): 0.55 (-1.07, -0.04), p = 0.03].

SIGNIFICANCE

Results suggest frontal and sagittal plane knee angles and moments in patients with knee OA evaluated using a treadmill-based system are reliable and valid.

Determination of the postoperative limb alignment following a high tibial osteotomy in patients with uni-compartmental knee osteoarthritis, review article

Objectives

High tibial osteotomy is an established surgical procedure for treatment of mal-aligned Varus knees due to medial compartment knee osteoarthritis. Aims are to evaluate whether post-operative axial alignment achieves good long-term results.

Methods and results

Literature search done and studies with a follow up period of 2 or more years were included. The mean postoperative mechanical axis varied widely from 3 to 16° with significant differences between the studies.

Conclusion

The results suggested that medial knee osteoarthritis can be treated successfully with HTO. The post-operative valgus angle should be between 3 and 13° of valgus to achieve good long-term results.

Osteoarthritis year in review 2019: mechanics

Mechanics play a critical - but not sole - role in the pathogenesis of osteoarthritis, and recent research has highlighted how mechanical constructs are relevant at the cellular, joint, and whole-body level related to osteoarthritis outcomes. This review examined papers from April 2018 to April 2019 that reported on the role of mechanics in osteoarthritis etiology, with a particular emphasis on studies that focused on the interaction between movement and tissue biomechanics with other clinical outcomes relevant to the pathophysiology of osteoarthritis. Studies were grouped by themes that were particularly prevalent from the past year. Results of the search highlighted the large exposure of knee-related research relative to other body areas, as well as studies utilizing laboratory-based motion capture technology. New research from this past year highlighted the important role that rate of exerted loads and rate of muscle force development - rather than simply force capacity (strength) - have in OA etiology and treatment. Further, the role of muscle activation patterns in functional and structural aspects of joint health has received much interest, though findings remain equivocal. Finally, new research has identified potential mechanical outcome measures that may be related to osteoarthritis disease progression. Future research should continue to combine knowledge of mechanics with other relevant research techniques, and to identify mechanical markers of joint health and structural and functional disease progression that are needed to best inform disease prevention, monitoring, and treatment.

High tibial osteotomy results in improved frontal plane knee moments, gait patterns and patient-reported outcomes

PURPOSE

The purpose of this study was to quantify changes in knee loading in the three clinical planes, compensatory gait adaptations and patient-reported outcome measures (PROMS) resulting from opening wedge high tibial osteotomy (HTO).

METHODS

Gait analysis was performed on 18 participants (19 knees) with medial osteoarthritis (OA) and varus alignment pre- and post-HTO, along with 18 controls, to calculate temporal, kinematic and kinetic measures. Oxford Knee Score, Knee Outcome Survey and visual analogue pain scores were collected. Paired and independent sample tests identified changes following surgery and deviations from controls.

RESULTS

HTO restored frontal and transverse plane knee joint loading to that of the control group, while reductions remained in the sagittal plane. Elevated frontal plane trunk sway (p = 0.031) and reduced gait speed (p = 0.042), adopted as compensatory gait changes pre-HTO, were corrected by the surgery. PROMs significantly improved (p ≤ 0.002). Centre of pressure (COP) was lateralised relative to the knee post-HTO (p < 0.001). Energy absorbed in the sagittal plane significantly increased post-HTO (p = 0.007), whilst work done in the transverse plane reduced (p ≤ 0.008). Pre-operative gait deviations from the control group that were retained post-HTO included smaller sagittal (p = 0.003) knee range of motion during gait, greater stance duration (p = 0.008) and altered COP location (anterior to the knee) in early stance (p = 0.025).

CONCLUSIONS

HTO surgery restored frontal and transverse plane knee loading to normal levels and improved PROMs. Gait adaptations known to reduce knee loading employed pre-HTO were not retained post-HTO. Some gait features were found to differ between post-HTO subjects and controls.

LEVEL OF EVIDENCE

II.

Predicting the knee adduction moment after high tibial osteotomy in patients with medial knee osteoarthritis using dynamic simulations

BACKGROUND

High tibial osteotomy (HTO) is a surgical treatment for knee osteoarthritis, which alters the load distribution in the tibiofemoral joint. To date, all surgical planning methods are based on radiographs, which do not consider the loading characteristics during ambulation. This study aimed to develop and validate a simulation tool for predicting the knee adduction moment (KAM) expected after a HTO using the patient pre-operative gait analysis data and dynamic simulations.

METHODS

Ten patients selected for a HTO underwent a gait analysis before surgery. Pre-operative gait data along with the planned correction angle were used for simulation of the KAM expected after leg realignment. After surgery, the same procedures of gait analysis were performed and post-operative KAM was compared to the simulation results.

RESULTS

Significant reductions of the KAM were observed after surgery. During gait at 1.2 m/s, means of the 1st peak KAM were 3.19 ± 1.03 (standard deviation), 1.21 ± 0.80 and 1.21 ± 0.71% BW × Ht for the conditions pre-operative, post-operative and simulation, respectively. Mean root-mean-square error for the KAM was 0.45% BW × Ht (range: 0.23-0.78% BW × Ht) and Lin's concordance coefficient for the 1st peak KAM was 0.813. An individual analysis showed high agreement for several patients and lower agreement for others. Possible changes in gait pattern after surgery may explain this variability.

CONCLUSION

A novel approach for surgical planning based on dynamic loading of the knee during ambulation is presented. The simulation tool is based on patient-specific gait characteristics and may improve the surgical planning procedures used to date.

Comparison of Clinical and Biomechanical Outcomes between Partial Fibulectomy and Drug Conservative Treatment for Medial Knee Osteoarthritis

Background

Upper partial fibulectomy has been preliminarily proved to have the efficacy for pain alleviation and improvement of function in patients with mild to moderate medial compartment knee osteoarthritis (KOA). However, the previous studies lack the control group with other treatments. The aim of this prospective, randomized controlled study is to compare the clinical and biomechanical effects between upper partial fibulectomy and drug conservative treatment on improvement of clinical pain, function, and gait for patients with mild to moderate medial knee osteoarthritis (KOA) and further discuss its biomechanical mechanism.

Methods

From August 2016 to February 2017, 49 and 48 patients with mild to moderate medial KOA were allocated to fibulectomy and drug groups. We assessed the patients' visual analog scale (VAS) pain score, Hospital for Special Surgery (HSS) knee score, limb alignment, passive flexion/extension range of motion (ROM) of the knee, and 3D gait kinematics and kinetics parameters before and after intervention. Repeated-measures ANOVA with Dunnett's post hoc assessment and multivariate analysis of variance were applied for intragroup and intergroup comparisons, respectively.

Results

The improvement in the fibulectomy group on the VAS pain score, HSS knee score, walking speed, and walking knee range of motion (ROM) was statistically better than that in the drug group. The decreased overall peak knee adduction moment (KAM) (decreased by 16.1%) and hip-knee-ankle (HKA) angle (decreased by 0.99° from a more varus alignment to a more neutral alignment) of the affected and operated side 1 year after surgery were observed in the fibulectomy group.

Conclusion

This research demonstrated that as a biomechanical intervention, upper partial fibulectomy can be a better choice in pain relief and function and gait improvement than drug conservative treatment for patients with early-stage knee OA. The long-term clinical outcomes, indication, and rationale for the improvement in clinical symptoms should be investigated further.

Development and validation of a prediction model for knee joint line orientation after high tibial osteotomy

Background

Maintenance of optimal knee joint line orientation (KJLO) is important after high tibial osteotomy (HTO). No tools, however, are currently available that could predict the value of postoperative KJLO before surgery. First, this study sought to determine the effects of various preoperative anatomical alignment parameters to postoperative KJLO. Based upon these analyses, we aimed to devise an equation that predicts the value of postoperative KJLO.

Methods

A total of 14 radiographic parameters were measured in preoperative and postoperative full-limb standing anteroposterior radiographs on 50 patients who underwent open-wedge HTO. The parameters were analysed using multivariable linear regression to predict KJLO after HTO. External validation of the equation was done with 20 patients who underwent HTO at another institution.

Results

After HTO, KJLO increased from − 0.8° to 2.9° (P < 0.001). Based on the multivariable linear regression analysis, an equation was derived that can estimate postoperative KJLO after HTO; postoperative KJLO(°) = 1.029 + 0.560 × preoperative KJLO(°) + 0.310 × preoperative tibia plateau inclination(°) + 0.463 × aimed correction angle(°). The adjusted coefficients of determination value for this equation was 0.721. The equation also showed good calibration and predictability in external validation with predicted squared correlation coefficient of 0.867.

Conclusions

This study analysed the effects of preoperative anatomical alignment parameters on the postoperative KJLO. An equation which predicts postoperative KJLO with preoperative anatomical alignment factors was devised and validated. This equation would help in selecting optimal patients for HTO and in selecting the optimal target correction angle in HTO.

Increased Posterior Tibial Slope After Medial Open-Wedge High Tibial Osteotomy May Result in Degenerative Changes in Anterior Cruciate Ligament

BACKGROUND

This study aimed at evaluating changes in posterior tibial slope angle (PTSA) and the anterior cruciate ligament (ACL) before and after medial open-wedge high tibial osteotomy (MOWHTO) through 2-staged arthroscopic findings and verified whether the ACLs would be affected by the changed PTSA. We also evaluated which predisposing factors could influence ACL changes after MOWHTO.

METHODS

From July 2010 to March 2016, 164 knees that could follow the second-look arthroscopy at the time of plate removal were enrolled. Radiologically, preoperative and postoperative hip-knee-ankle angle, femorotibial angle, medial proximal tibial angle, and PTSA were evaluated. Based on our previous study, we assessed the ACL using the macroscopic grading system (normal, abnormal degenerative, and partially ruptured ACL) by first- and second-look arthroscopy and compared it before and after HTO. The correlation between changes in PTSA (△PTSA) and ACL was evaluated. We also assessed predisposing factors that might affect ACL changes.

RESULTS

Mean age at the time of osteotomy was 57.2 ± 5.1 years and time interval between the 2-stage arthroscopies was 26.3 ± 4.0 months. PTSA significantly increased after MOWHTO (P < .001). ACL stage at second-look arthroscopy was significantly progressed compared to first-look findings (P < .001). △PTSA was larger in the progressed group (2.1°; P < .001). Multivariate logistic regression indicated that greater body mass index (odds ratio, 1.2; P = .029) and larger △PTSA (odds ratio, 1.3; P = .008) were predisposing factors.

CONCLUSION

Increased posterior tibial slope following MOWHTO may result in degenerative ACL changes. Greater body mass index and larger △PTSA were predisposing factors for ACL degeneration after MOWHTO.

Degenerative Meniscal Tears and High Tibial Osteotomy: Do Current Treatment Algorithms Need to Be Realigned?

Degenerative medial meniscal tears (DMMTs) are a common feature of early knee osteoarthritis (OA). Varus alignment is a strong risk factor for medial compartment knee OA and its progression. We propose that high tibial osteotomy (HTO) should be considered much earlier in the treatment algorithm for patients presenting with recurring medial knee pain, varus alignment, and DMMT, absent of radiographic OA. We provide rationale for investigating HTO as a disease-modifying intervention for secondary prevention in knee OA, and present case examples as low-level proof of principle. Finally, caveats and challenges are discussed along with proposed future research.

Distal Tibial Tuberosity Arc Osteotomy in Open-Wedge Proximal Tibial Osteotomy to Prevent Patella Infra

Open-wedge high tibial osteotomy is considered to be an effective surgical intervention for medial compartmental knee osteoarthritis. However, patella infra, which has been reported to be a result of tuberosity distalization after open-wedge high tibial osteotomy, changes the native patellofemoral biomechanics. This could raise abnormal patellofemoral contact stresses, which might be the trigger of patellofemoral arthrosis. To minimize the reduction in patellar height, we have developed a technique called open-wedge distal tuberosity tibial osteotomy. The benefits of this technique include increased bone-to-bone contact of the distal tuberosity cut surface after correction by cutting an arc osteotomy around the hinge position, which is the center of rotation. This technique also provides cortical support at the anterior osteotomy site without additional bone defect and, therefore, may be advantageous against weight-bearing stress on the osteotomy site. In all, open-wedge distal tuberosity tibial osteotomy could potentially be a unique open-wedge osteotomy that eliminates the risk for postoperative patellofemoral osteoarthritis and also could theoretically encourage rapid healing of the osteotomy, which could lead to early return to full physical activity.

Improved Methods to Measure Outcomes After High Tibial Osteotomy

Observational studies suggest high tibial osteotomy produces substantial improvements in knee loading and stability that can limit the progression of joint damage; decrease pain; improve function and quality of life; and delay the need for knee replacement surgery. It can be cost-effective in knee osteoarthritis. However, systematic reviews and clinical practice guidelines are unable to provide strong recommendations, because limited high-level evidence supports its therapeutic value versus other treatments. We describe findings suggesting it can improve outcomes important to knee joint structure and function, patient quality of life, and health care systems. Future clinical trials are warranted and required.

High Tibial Osteotomy: Review of Techniques and Biomechanics

High tibial osteotomy becomes increasingly important in the treatment of cartilage damage or osteoarthritis of the medial compartment with concurrent varus deformity. HTO produces a postoperative valgus limb alignment with shifting the load-bearing axis of the lower limb laterally. However, maximizing procedural success and postoperative knee function still possess many difficulties. The key to improve the postoperative satisfaction and long-term survival is the understanding of the vital biomechanics of HTO in essence. This review article discussed the alignment principles, surgical technique, and fixation plate of HTO as well as the postoperative gait, musculoskeletal dynamics, and contact mechanics of the knee joint. We aimed to highlight the recent findings and progresses on the biomechanics of HTO. The biomechanical studies on HTO are still insufficient in the areas of gait analysis, joint kinematics, and joint contact mechanics. Combining musculoskeletal dynamics modelling and finite element analysis will help comprehensively understand in vivo patient-specific biomechanics after HTO.

Change in adduction moment following medial open wedge high tibial osteotomy: a meta-analysis

Background

This meta-analysis was designed to quantify adduction moment loss, to evaluate the relationship between changes in mechanical axis alignment and adduction moment, and to assess whether sagittal plane moment is altered after medial open wedge high tibial osteotomy (HTO).

Methods

Following preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, all studies reporting preoperative and postoperative peak knee adduction moment or change in peak knee adduction moment from before to after surgery in patients who underwent medial open wedge HTO were included.

Results

Nine studies were included in the meta-analysis. The pooled mean difference in adduction moment from before to after medial open wedge HTO was 1.44% Nm/body weight (BW)xheight (HT) (95% confidence interval [CI]: 1.33 to 1.55% Nm/BWxHT; P < 0.001; I² = 4%). However, flexion (0.18% Nm/BWxHT, 95% CI: -0.50 to 0.86% Nm/BWxHT; P = 0.61; I² = 79%) and extension (0.15% Nm/BWxHT, 95% CI, − 0.37 to 0.68% Nm/BWxHT; P = 0.56; I² = 46%) moments did not differ significantly from before to after surgery. Alignment correction amount and postoperative final valgus alignment were not significantly associated with difference in adduction moment from before to after surgery.

Conclusion

Knee adduction moment after medial open wedge HTO decreased to 60% of the preoperative level. However, this adduction moment decrement was not affected by the magnitude of alignment correction. In addition, there was no change in sagittal plane knee moment, including flexion and extension moments, from before to after medial open wedge HTO.

Level of Evidence: Meta-analysis (Level II).

Dynamic analysis of varus knee using a subject-specific multibody model of the knee before and after osteotomy

Varus misalignment of the hip-knee-ankle angle causes greater loads on the medial compartment of the knee and increases the risk of developing knee osteoarthritis. High tibial osteotomy is a surgical method where the load-bearing axis is shifted laterally. The purpose of this study is to define a subject-specific three-dimensional multibody model of the knee to investigate the effect of osteotomy on cartilages and menisci during the stance phase of gait. It is assumed that osteotomy transfers load-bearing to the lateral parts of the knee. Magnetic resonance images of a patient with varus alignment were used to generate the geometries of the bones, cartilages, and menisci. Then, an experimental approach was used to determine the parameters for the stiffness matrices and compliant contact models of the tibio-menisco-femoral articulations with the use of finite element solutions. As indicated by the research findings, the contact force at the medial cartilage decreased as the load-bearing axis was transferred to the lateral parts. This subject-specific noninvasive analysis of contact force can be considered as a preoperative assessment tool for the surgeon. to predict the effects of high tibial osteotomy and the shifting of the load-bearing axis to the soft tissues of the knee.

Effect of Lower Limb Alignment in Medial Meniscus-Deficient Knees on Tibiofemoral Contact Pressure

Background:

Degenerative medial meniscal tears and subsequent partial meniscal resection compromise meniscal function and lead to an overload of the medial compartment. In addition, lower limb alignment plays a key role in load distribution between the medial and lateral knee compartments, and varus alignment is a potential risk factor for medial osteoarthritis.

Purpose/Hypothesis:

The purpose of this biomechanical study was to investigate the effect of valgus and varus alignment on peak pressure and contact area in knees with concomitant horizontal medial meniscal tears and subsequent leaflet resection. It was hypothesized that varus alignment in combination with meniscal loss leads to the highest peak pressure within the medial compartment.

Study Design:

Controlled laboratory study.

Methods:

Six fresh-frozen human cadaveric knees were axially loaded using a 1000-N compressive load in full extension with the mechanical axis rotated to intersect the tibial plateau at 40%, 45%, 50%, 55%, and 60% of its width (TPW) to simulate varus and valgus alignment. Tibiofemoral peak contact pressure and contact area of the medial and lateral compartments were determined using pressure-sensitive foils in each of 4 different meniscal conditions: intact, 15-mm horizontal tear of the posterior horn, inferior leaflet resection, and resection of both leaflets.

Results:

The effect of alignment on peak pressure (normalized to the neutral axis) within the medial compartment in cases of an intact meniscus was measured as follows: varus shift resulted in a mean increase in peak pressure of 18.5% at 45% of the TPW and 37.4% at 40% of the TPW, whereas valgus shift led to a mean decrease in peak pressure of 8.7% at 55% of the TPW and 23.1% at 60% of the TPW. Peak pressure changes between the intact meniscus and resection within the medial compartment was less in valgus-aligned knees (0.21 MPa at 60% TPW, 0.59 MPa at 50% TPW, and 0.76 MPa at 40% TPW). Contact area was significantly reduced after partial meniscal resection in the neutral axis (intact, 553.5 ± 87.6 mm²; resection of both leaflets, 323.3 ± 84.2 mm²; P < .001). This finding was consistent in any alignment.

Conclusion:

Both partial medial meniscal resection and varus alignment led to an increase in medial compartment peak pressure. Valgus alignment prevented medial overloading by decreasing contact pressure even after partial meniscal resection. A horizontal meniscal tear did not influence peak pressure and contact area even in varus alignment.

Clinical Relevance:

As a clinical consequence, partial meniscal resection should be avoided to maintain the original biomechanical behavior, and the mechanical axis should be taken into account if partial meniscectomy is necessary.

Gait biomechanics after combined HTO-ACL reconstruction versus HTO alone: A matched cohort study

The purpose of the present study was to compare bilateral external knee moments during gait in patients with concomitant medial compartment knee OA, varus alignment and chronic anterior cruciate ligament (ACL) deficiency who underwent either medial opening-wedge high tibial osteotomy alone (HTO) or simultaneous HTO and ACL reconstruction (HTO-ACLR). Fifty-two patients (26 matched pairs) completed 3D gait analysis preoperatively and at a minimum 5 years postoperatively. Patients were matched for preoperative age, sex, body mass index and magnitude of correction. Primary outcomes selected a priori were the peak knee adduction moment (KAM) and knee flexion (KFM) moment during stance. Moments were compared using mixed model repeated measures analysis of variance (ANOVA). For the peak KAM, there was a significant time by limb interaction. For both groups, there were similar reductions in the peak KAM 5 years postoperatively in the surgical limb only [-1.34 %BW × Ht (-1.71, -0.96) and -1.72 %BW × Ht (-1.99, -1.44) for HTO and HTO-ACLR, respectively]. For the peak KFM, there was a significant time by group by limb interaction. There was a decrease in the peak KFM 5 years postoperatively in the HTO group [-0.88 %BW × Ht (-1.45, -0.31)] but not in the HTO-ACLR group [0.03 %BW × Ht (-0.43, 0.48)]. These results suggest that individuals with medial knee OA, varus alignment and chronic ACL deficiency who undergo simultaneous medial opening-wedge HTO and ACL reconstruction may not experience the same long-term (5 year) changes in sagittal plane knee biomechanics observed in patients undergoing HTO alone. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Gait retraining using real-time feedback in patients with medial knee osteoarthritis: Feasibility and effects of a six-week gait training program

BACKGROUND

The knee adduction moment (KAM) is often elevated in medial knee osteoarthritis (KOA). The aim of this study was to evaluate effects on KAM and patient-reported outcomes of a six-week gait training program.

METHODS

Twenty-one patients (61 ± 6 years) with KOA participated in a six-week biofeedback training program to encourage increased toe-in (all patients) and increased step-width (five patients). Patients received real-time visual feedback while walking on an instrumented treadmill. We analysed the effect of the gait modification(s) on peak KAM in week six and three and six months post-training. We also evaluated the effect on pain and functional ability.

RESULTS

Of 21 patients starting the program, 16 completed it with high attendance (15 and 16 respectively) at the three and six month follow-ups. First peak KAM was significantly reduced by up to 14.0% in week six with non-significant reductions of 8.2% and 5.5% at the follow-ups. Functional ability (assessed using the WOMAC questionnaire) improved significantly after the training (eight point reduction, p = 0.04 in week six and nine point reduction, p = 0.04 at six-month follow-up). There was also a trend towards reduction in WOMAC pain (p = 0.06) at follow-up.

CONCLUSIONS

Biofeedback training to encourage gait modifications is feasible and leads to short-term benefits. However, at follow-up, reductions in KAM were less pronounced in some participants suggesting that to influence progression of KOA in the longer term, a permanent regime to reinforce the effects of the training program is needed. Trial number: ISRCTN14687588.

Inverted V-Shaped High Tibial Osteotomy for Medial Osteoarthritic Knees With Severe Varus Deformity

A hemi-closing-wedge and hemi-opening-wedge, inverted V-shaped high tibial osteotomy with local bone graft has been reported to be an effective surgical procedure for medial osteoarthritis of the knee. In this procedure, an inverted V-shaped osteotomy is made and a thin wedged bone block is resected from the lateral side and implanted in the medial opening space created after valgus correction. This procedure can provide sufficient valgus correction of the knee with severe varus deformity more easily than can closing-wedge high tibial osteotomy. The inverted V-shaped osteotomy does not change the posterior tibial slope, the patellar height, or the length of the lower limb at all because the center of tibial alignment correction by the inverted V-shaped osteotomy is located near the center of rotation of angulation of the lower-limb deformity. We recently modified this procedure by performing biplanar osteotomy, developing useful cutting guides, and fixing the tibia with a lateral locking compression plate. The surgical technique is described to enable the reproducible creation of the hemi-closing-wedge and hemi-opening-wedge, inverted V-shaped osteotomy with the locking plate for medial osteoarthritic knees with moderate or severe varus deformity.