High tibial osteotomy

Medial Opening Wedge Proximal Tibial Osteotomy: Lessons Learned from a Series of 175 Consecutive Cases

INTRODUCTION

High tibial osteotomy (HTO) is a surgical procedure aimed at inhibiting the progression of osteoarthritis of the knee joint. The aim of this study was to identify factors influencing the functional outcome after opening wedge valgus HTO.

METHODS

A total of 175 cases (155 patients) of varus-correcting high tibial open-wedge osteotomies using the Tomofix plate were reviewed retrospectively. Patients answered the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire and 4 survey follow-up questions.

RESULTS AND DISCUSSION

A total of 76 of the 155 patients studied (84 of the 175 knees) completed the KOOS questionnaire, on average 3.1 years (SD 1.8 years) after the surgery. The median scores (with median absolute deviations [MAD]) for the KOOS pain, symptoms, daily activities, sports, and quality of life sections were, respectively, 76.4 (MAD 12.5), 75.0 (MAD 14.3), 85.3 (MAD 11.8), 50.0 (MAD 25.0), and 59.4 (MAD 21.9). No cases of nonunion were observed throughout the length of the study. Identified predictors of worse outcomes were higher weight and body mass index, limited knee flexion, genu varum and tibial varus of small magnitude, active smoking status at the time of surgery, further surgery for plate removal, and some grades of chondropathy in the patellofemoral, medial tibial, and femoral compartments. Patient gender, joint obliquity and over- or undercorrection were not associated with any of the outcomes.

CONCLUSION

This study shows good results following valgus HTO that are comparable to outcomes following total knee arthroplasty, reinforcing the option of HTO as a valid alternative for total knee arthroplasty.

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.

No differences in clinical outcomes and cartilage repair between opening wedge and closed wedge high tibial osteotomies at short-term follow-up: A retrospective case series analysis

PURPOSE

The aim of this study was to assess differences in clinical outcomes and postoperative cartilage repair between opening wedge high tibial osteotomy (OWHTO) and closed wedge HTO (CWHTO) for medial osteoarthritis (OA) of the knee.

METHODS

A total of 90 knees of 76 patients who underwent OWHTO (45 knees of 40 patients) and CWHTO (45 knees of 36 patients) was followed-up for 2 years. Cartilage repair at the medial compartment was arthroscopically classified into the following stages: Stage 1 (no reparative change); Stage 2 (partial coverage with white cartilaginous tissue); and Stage 3 (full coverage with white cartilaginous tissue). Clinical outcomes were assessed using Knee Society scores, and radiographic assessment was carried out by anatomical femorotibial angle (aFTA).

RESULTS

Regarding preoperative OA grade, varus alignment, and function score, CWHTO patients showed more advanced OA status than OWHTO patients. Knee scores and function scores were significantly improved after surgery with both HTO procedures (P < 0.05), with no significant difference between the two procedures. Cartilage repair of stage 2 or 3 was found in more than 80% of the subjects in the medial femoral condyle and more than 60% in the medial tibial condyle. However, there were no significant differences between the two HTO procedures. Multivariate logistic regression analysis showed that preoperative International Cartilage Repair Society (ICRS) grade was the only factor affecting cartilage repair.

CONCLUSIONS

CWHTO improved clinical outcomes and cartilage status as much as OWHTO. Although the effects of cartilage repair on clinical outcomes are unknown, HTO is an effective treatment option even for severe medial OA of the knee.

Allogenic Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Are More Effective Than Bone Marrow Aspiration Concentrate for Cartilage Regeneration After High Tibial Osteotomy in Medial Unicompartmental Osteoarthritis of Knee

PURPOSE

The purpose of this study was to compare the outcome of cartilage regeneration between bone marrow aspirate concentrate (BMAC) augmentation and allogeneic human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSCs) transplantation in high tibial osteotomy (HTO) with microfracture (MFX) for medial unicompartmental osteoarthritis (OA) of the knee in the young and active patient.

METHODS

Between January 2015 and December 2019, the patients who underwent HTO and arthroscopy with MFX combined with BMAC or allogeneic hUCB-MSCs procedure for medial unicompartmental OA with kissing lesion, which was shown full-thickness cartilage defect (≥ International Cartilage Repair Society [ICRS] grade 3B) in medial femoral cartilage and medial tibial cartilage, were include in this study. Retrospectively we compared clinical outcomes, including Hospital for Special Surgery score, Knee Society Score (KSS) pain and function, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score between BMAC and hUCB-MSCs group at minimum of 1-year follow-up. Also, second-look arthroscopy was performed simultaneously with removal of the plate after complete bone union. Cartilage regeneration was graded by the ICRS grading system at second-look arthroscopy. Radiological measurement including hip-knee-ankle (HKA) angle, posterior tibial slope angle, and correction angle were assessed.

RESULTS

Of 150 cases that underwent HTO with MFX combined with BMAC or allogeneic hUCB-MSCs procedure for medial unicompartmental OA, 123 cases underwent plate removal and second-look arthroscopy after a minimum of 1 year after the HTO surgery. Seventy-four cases were kissing lesion in medial femoral cartilage and medial tibial cartilage during initial HTO surgery. Finally, the BMAC group composed of 42 cases and hUCB-MSCs group composed of 32 cases were retrospectively identified in patients who had kissing lesions and second-look arthroscopies with a minimum of 1 year of follow-up. At the final follow-up of mean 18.7 months (standard deviation = 4.6 months), clinical outcomes in both groups had improved. However, there were no significant differences between the IKDC, WOMAC, or KSS pain and function scores in the 2 groups (P > .05). At second-look arthroscopy, the ICRS grade was significantly better in the hUCB-MSC group than in the BMAC group in both medial femoral and medial tibial cartilage (P = .001 for both). The average ICRS grade of the BMAC group improved from 3.9 before surgery to 2.8 after surgery. The average ICRS grade of the hUBC-MSC group improved from 3.9 before surgery to 2.0 after surgery. Radiological findings comparing postoperative HKA angle, posterior tibial slope angle, and correction angle showed no significant differences between the groups (P > .05). Therefore it was found that the postoperative correction amount did not affect the postoperative cartilage regeneration results.

CONCLUSIONS

We found that the hUCB-MSC procedure was more effective than the BMAC procedure for cartilage regeneration in medial unicompartmental knee OA even though the clinical outcomes improved regardless of which treatment was administered.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Intravenous Tranexamic Acid Has Benefit for Reducing Blood Loss after Open-Wedge High Tibial Osteotomy: A Randomized Controlled Trial

(1) Background: the purpose of this study was to investigate the efficacy and safety of intravenous (IV) administration of tranexamic acid (TXA) in patients undergoing medial opening wedge high tibial osteotomy (MOWHTO). (2) Methods: a total of 73 patients were randomly allocated into two groups (TXA group and control group). The primary outcome was total perioperative calculated blood loss after MOWHTO. Secondary outcomes included self-reported pain severity using a 10-point visual analog scale (VAS) and the EuroQol-5 Dimension (EQ-5D) questionnaire. The postoperative allogeneic transfusion rate and wound complications were compared. Deep vein thrombosis (DVT) incidence was compared by conducting DVT computed tomography imaging. (3) Results: the total blood loss after surgery was 470.9 mL in the TXA group and 739.3 mL in the control group, showing a significant difference (p < 0.001). There were no differences in pain VAS scores between the two groups (all p > 0.05). No difference in preoperative EQ-5D scores for any items existed between the two groups. No transfusion was performed in either group. There was no difference in DVT incidence or the rate of wound complications between the two groups. (4) Conclusion: in patients undergoing MOWHTO, IV TXA reduces total blood loss and drainage amount. However, no additional benefits in clinical outcomes, transfusion rate, or wound complications were apparent, with similar DVT incidence rates.

Clinical Feasibility of Multi-Acquisition Variable-Resonance Image Combination-Based T2 Mapping near Hip Arthroplasty

Background: Hip arthroplasty is increasingly prevalent, and early detection of complications can improve outcomes. Quantitative magnetic resonance imaging (qMRI) methods using multi-acquisition variable-resonance image combination (MAVRIC) may allow for the assessment of soft tissues in close proximity to hip arthroplasty devices. Question/Purposes: We sought to determine the clinical feasibility of MAVRIC-based T2 mapping as a qMRI approach for assessing synovial reactions in patients with a hip arthroplasty device. We hypothesized that there would be differences in T2 metrics by synovial type, clinical impression, and clinical findings related to synovitis. Methods: We conducted a cross-sectional study of 141 subjects with 171 hip arthroplasties with greater than 1 year post-implantation. We enrolled subjects who had had a primary total hip arthroplasty or hip resurfacing arthroplasty between May 2019 and March 2020, excluding those with a revision hip arthroplasty and those with standard safety contraindications for receiving an MRI. Institutional standard 2D fast spin echo (FSE), short-tau inversion recovery (STIR), and susceptibility-reduced MAVRIC morphological MR images were acquired for each hip and followed by a dual-echo acquisition MAVRIC T2 mapping sequence. Results: While 131 subjects (81%) were classified as having a "normal" synovial reaction, significantly longer T2 values were found for fluid synovial reactions compared with mixed reactions. In addition, subjects with synovial dehiscence and decompression present had T2 prolongation. Larger synovial volumes were found in subjects with low-signal intensity deposits. Conclusions: MAVRIC-based T2 mapping is clinically feasible and there are significant quantitative differences based on type of synovial reaction. Patients undergoing hip arthroscopy revision surgery will warrant comparison of T2 values with direct histologic assessment of a tissue sample obtained intraoperatively. The approach used in this study may be used for a quantitative evaluation and monitoring of soft tissues around metal implants.

The Minimal Clinically Important Difference (MCID) for the WOMAC and Factors Related to Achievement of the MCID After Medial Opening Wedge High Tibial Osteotomy for Knee Osteoarthritis

BACKGROUND

Many approaches have been used to determine the minimal clinically important difference (MCID) in patients undergoing total knee arthroplasty, but the MCID for outcome measures after medial opening wedge high tibial osteotomy (MOWHTO) for the treatment of medial compartment knee osteoarthritis (OA) has not been reported.

PURPOSE

To define the MCID for the Western Ontario and McMaster Universities Arthritis Index (WOMAC) after MOWHTO and to identify risk factors for not achieving the MCID.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Among patients with medial compartment knee OA who underwent MOWHTO, 174 patients who were followed for 2 years were included in the study. The MCID and substantial clinical benefit (SCB) for the WOMAC were determined using the anchor-based method with a 15-item questionnaire. Preoperative OA severity was measured by the Kellgren-Lawrence (K-L) grading system, and the acceptable range of the postoperative weightbearing line ratio was 50% to 70%. Patients were divided into 2 groups based on whether the MCID and SCB were achieved, and then factors related to failure to achieve the MCID and SCB were analyzed using multivariate logistic regression analysis.

RESULTS

The MCID for the WOMAC was 4.2 points for the pain subscale, 1.9 points for the stiffness subscale, 10.1 points for the function subscale, and 16.1 points for the total. Additionally, the SCB for the WOMAC was 6.4 for pain, 2.6 for stiffness, 16.4 for function, and 25.3 for the total. Overall, 116 (66.7%), 99 (56.9%), 127 (73.0%), and 128 (73.6%) patients achieved the MCID for the WOMAC pain, stiffness, function, and total, respectively, after MOWHTO. The odds of not achieving the MCID for the WOMAC total were 1.09 times greater (95% CI, 1.05-1.13; P < .001) in patients with a low preoperative WOMAC total score (cutoff values: 10.5 for pain, 3.5 for stiffness, 34.5 for function, and 51.0 for the total), 11.77 times greater (95% CI, 3.68-37.70; P < .001) in patients with K-L grade 4 OA compared with K-L grades 2 or 3 OA, and 8.39 times greater (95% CI, 2.98-23.63; P < .001) in patients with undercorrection or overcorrection. A low preoperative WOMAC score, K-L grade 4 OA, and undercorrection or overcorrection were also associated with not achieving the SCB for the WOMAC total (all P < .05).

CONCLUSION

Patients treated with a MOWHTO require a 16.1-point improvement in the WOMAC total score to achieve a MCID from the procedure. Low preoperative WOMAC scores, severe OA, and undercorrection or overcorrection were related to failure to achieve the MCID.

Alignment adjustment using the Valgus stress technique can increase the surgical accuracy of novice surgeons during medial opening-wedge high Tibial osteotomy

Background

The purpose of this study was to compare the degree of accuracy of coronal alignment correction with use of the “alignment adjustment under valgus stress technique” between expert and novice surgeons during medial opening-wedge high tibial osteotomy (MOWHTO).

Methods

Forty-eight patients who underwent MOWHTO performed by an expert surgeon (expert group) and 29 by a novice surgeon (novice group) were enrolled in analysis. During surgery, lower-extremity alignment was corrected using the “alignment adjustment under valgus stress technique”. Normocorrection was defined as a weight-bearing line ratio between 55 and 70% and the correction accuracy was compared between expert and novice groups using the ratio of normocorrection to outliers. The clinical outcomes were also compared using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at 1 year after surgery.

Results

The undercorrection rate was 14.6% in the expert group and 13.8% in the novice group, while the overcorrection rate was 2.1% in the expert group and 3.4% in the novice group. In the ratio of normocorrection to outliers, no difference was found between the two groups at the one-year follow-up visit (83.3% in the expert group vs. 82.8% in the novice group; p > 0.05). Also, no significant differences were seen in WOMAC subscores immediately preoperatively and at 1 year after surgery (all p > 0.05).

Conclusion

Adhering to the “alignment adjustment under valgus stress technique” protocol enabled novice surgeons to achieve similar surgical accuracy as that of an expert surgeon in coronal alignment during MOWHTO.

Level of evidence

Level III.

The patellofemoral joint does not deteriorate clinically after open-wedge high tibial osteotomy

BACKGROUND

After high tibial osteotomy (HTO), the loading of the lateral compartment can be increased. Moreover, the change of patellar height may adversely affect the patellofemoral joint and functional outcomes.

HYPOTHESIS

We hypothesized that the cartilage of the lateral compartment and patellofemoral joint would worsen after open-wedge HTO and the overcorrection of HTO could worsen the cartilage state of the patellofemoral joint. We evaluated the cartilage status and clinical results after medial open-wedge HTO and the factors affecting the outcomes.

MATERIALS AND METHODS

From 2011 to 2018, 49 patients who had a mean age of 54.9 years and who underwent medial open-wedge HTO were selected. Plate removal was performed at a mean of 37.0 (range, 13-89) months after HTO, whereas diagnostic arthroscopy was performed during medial open-wedge HTO and plate removal. The cartilage status of each joint and the clinical results, including the Hospital for Special Surgery (HSS) score, Knee Society knee score (KS) and function score (FS), and patellar score, were compared. We evaluated the postoperative changes in the cartilage status and clinical scores. Additionally, we evaluated whether the postoperative correction degree could affect the clinical results.

RESULT

After medial open-wedge HTO, the patellar height decreased. There was no change in the cartilage at the patellar and femoral trochlear groove. The HSS score, KS, and FS improved, but the patellar score remained unchanged. In the overcorrection group, the cartilage status significantly deteriorated at the lateral tibia condyle as compared with that in the undercorrection group. Higher preoperative clinical scores were associated with less postoperative improvement.

DISCUSSION AND CONCLUSION

The outcomes in the patellofemoral joint, including the cartilage condition and clinical scores, did not change after open-wedge HTO, despite patellar infera. Additionally, they were not influenced by the correction degree. Higher preoperative clinical scores were associated with less postoperative improvement.

LEVEL OF EVIDENCE

IV; retrospective study.

Association of Gap Healing With Angle of Correction After Opening-Wedge High Tibial Osteotomy Without Bone Grafting

Background:

Studies have reported that opening wedge high tibial osteotomy (OWHTO) without bone grafting has outcomes that are similar to or even better than those of OWHTO with bone grafting, especially after use of a locking plate. However, a consensus on managing the gap after OWHTO has not been established.

Purpose:

To determine the degree of gap healing achieved without bone grafting, the factors associated with gap healing, and whether additional gap healing would be obtained after plate removal.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This retrospective study included 73 patients who underwent OWHTO without bone grafting between 2015 and 2018. Patients in the study were divided into 2 groups based on the correction angle: small correction group (<10°; SC group) and large correction group (≥10°; LC group). The locking plate used in OWHTO was removed at a mean of 13.5 months after surgery in 65 patients. Radiographic indexes were measured: gap filling height, gap vacancy ratio (GVR), and osteotomy filling index. The acceptable gap healing was defined as an osteotomy filling index ≥3. The factors related to gap healing around the osteotomy site were selected after multicollinearity analysis.

Results:

Although both groups achieved acceptable gap healing regardless of the correction angle, the SC group showed higher and earlier gap healing than did the LC group (gap healing rate 81.4% in the SC group vs 41.7% in the LC group at 3 months postoperatively). The GVR was 8.6% in the SC group and 15.3% in the LC group at 12 months after surgery (P = .005). Both the amount of time that elapsed after surgery and the correction angle were associated with gap healing (P < .05). Additional gap healing was observed after plate removal, as the GVR decreased 2.7% more in the patients with plate removal than in patients who did not have plate removal (P = .012).

Conclusion:

All patients achieved acceptable gap healing without bone graft. The degree of gap healing was higher in the SC group and increased over time. Gap healing was promoted after plate removal. Considering the results of this study, a bone graft is not necessary in routine OWHTO in terms of gap healing.

Using the Lower Limb Adduction Angle to Predict Postoperative Knee Joint-Line Obliquity After Open-Wedge High Tibial Osteotomy

Background:

Knee joint-line orientation is altered after open-wedge high tibial osteotomy (OWHTO), and excessive joint-line obliquity (JLO) can adversely affect outcomes. Little is known regarding preoperative prediction of postoperative knee JLO.

Purpose/Hypothesis:

The purpose of this study was to assess the correlation between the amount of lower limb adduction and changes in knee JLO after OWHTO. The hypothesis was that postoperative knee JLO could be predicted using the amount of lower limb adduction after OWHTO.

Study Design:

Case series; Level of evidence, 4.

Methods:

The records of 67 patients (77 knees) who underwent OWHTO for medial compartment osteoarthritis were retrospectively reviewed. The mechanical hip-knee-ankle (HKA) axis, lateral distal femoral angle, medial proximal tibial angle (MPTA), knee JLO, ankle JLO, and joint-line convergence angle were measured on standing whole-leg plain radiographs preoperatively and at 1 year postoperatively. The limb adduction angle was defined as the angle between the native weightbearing line (WBL) and the planned WBL on preoperative standing whole-leg plain radiographs. The predicted knee JLO was calculated as the sum of the preoperative knee JLO and the limb adduction angle. Multivariable linear regression analysis was used to identify the preoperative radiologic factors associated with the postoperative knee JLO. The agreement between postoperative and predicted values was determined using intraclass correlation coefficients (ICCs).

Results:

The estimated limb adduction angle was 4.2° ± 1.3°, and the predicted knee JLO was 4.9° ± 3.0°. The actual postoperative knee JLO was 4.5° ± 2.4°, which was a significant increase from 0.7° ± 2.4° preoperatively (P < .001). Excellent agreement was found between the predicted knee JLO and postoperative knee JLO (ICC = 0.928; P < .001). Limb adduction angle and changes in preoperative MPTA were significantly associated with changes in knee JLO (P < .001). On multivariable linear regression analysis, preoperative knee JLO and limb adduction angle were significantly associated with postoperative knee JLO (P < .001; R² = 0.83).

Conclusion:

Changes in knee JLO after OWHTO were associated with adduction of the lower limb after OWHTO. During preoperative planning, postoperative knee JLO can be predicted as the sum of the preoperative knee JLO and the limb adduction angle between the preoperative WBL and planned WBL.

The Fate of Bone Marrow Lesions After Open Wedge High Tibial Osteotomy: A Comparison Between Knees With Primary Osteoarthritis and Subchondral Insufficiency Fractures

BACKGROUND

Subchondral insufficiency fracture of the knee (SIFK) is characterized by a subchondral lesion that may lead to end-stage osteoarthritis (OA). In patients who have SIFK in a precollapse state with varus malalignment, a joint-preserving technique such as open wedge high tibial osteotomy (OWHTO) should be considered.

PURPOSE

To evaluate the efficacy of OWHTO in primary OA and SIFK-dominant OA by clinical and radiological evaluations including magnetic resonance imaging (MRI).

STUDY DESIGN

Cohort study; Level of evidence 3.

METHODS

A total of 33 SIFK-dominant OA knees and 66 with primary OA that underwent biplanar OWHTO between March 2014 and February 2016 were included after 1:2 propensity score matching. The MRI Osteoarthritis Knee Score was used to assess bone marrow lesions (BMLs) preoperatively and at follow-up. The weightbearing line ratio, the hip-knee-ankle angle, and the joint line convergence angle were measured. The clinical outcomes assessed were range of motion, the American Knee Society Score, and the Western Ontario and McMaster University (WOMAC) score.

RESULTS

The mean follow-up period was 41.2 ± 12.6 months. The distribution of preoperative BML grade in the SIFK-dominant OA group was significantly higher in both the femur and tibia (P < .001 and <.001, respectively) than that in the primary OA group. However, the difference was not significant postoperatively (femur, P = .425; tibia, P = .462). In both groups, postoperative BMLs showed significant improvement compared with preoperative BMLs (primary OA [femur, P < .001; tibia, P = .001] and SIFK-dominant OA [femur, P < .001; tibia, P < .001]). The WOMAC pain score was higher in the SIFK-dominant OA group preoperatively (primary OA, 7.0 ± 3.73; SIFK-dominant OA, 9.17 ± 2.6; P = .032) even though it was not different at the final follow-up (primary OA, 2.11 ± 1.7; SIFK-dominant OA, 1.79 ± 1.32; P = .179).

CONCLUSION

OWHTO is an effective procedure not only for primary OA but also for SIFK-dominant OA. OWHTO can improve BMLs, which represent the main pathological feature of SIFK. Therefore, in patients who have SIFK with varus malalignment, OWHTO can be an attractive treatment option for preserving the joint and enhancing subchondral bone healing.

The Effect of Cartilage Lesion in the Lateral Compartment of the Knee on the Surgical Outcome of Medial Open-Wedge High Tibial Osteotomy

The aim of this study was to identify the effect of cartilage lesion in the lateral compartment of the knee on the surgical outcome of medial open-wedge high tibial osteotomy (MOWHTO). A total of 172 consecutive patients who underwent MOWHTO were evaluated retrospectively. Among the patients who underwent second-look arthroscopic assessment, 30 patients with lateral compartment cartilage lesion (group 1: ≥ grade 2 cartilage lesion according to the International Cartilage Repair Society [ICRS] grading system) and 64 patients with normal or near-normal lateral compartment cartilage (group 2: grade 0 or 1 cartilage lesion according to the ICRS grading system) were included in the analysis. Each patient was evaluated for the following variables: clinical scores, radiographic osteoarthritis grade, and comparative measurement under arthroscopy. All clinical scores were similar between the two groups preoperatively and at the time of second-look operation. Group 1 showed a significantly higher osteoarthritis grade in the lateral compartment of the knee on the 30 degree flexed posteroanterior view according to the International Knee Documentation Committee grading system preoperatively (p = 0.005) and at the time of second-look operation (p = 0.002). In regard to the comparative measurement under arthroscopy, the size of cartilage lesion on the medial compartment decreased by time in both groups (p = 0.000), whereas the size of cartilage lesion on the lateral compartment increased by time in both groups (p = 0.004). However, the degree of change in the cartilage lesion size in each compartment of the knee over time did not significantly differ between the two groups. Regarding the cartilage lesion grade in the lateral compartment, there was no statistically significant difference in the frequency of deterioration between the two groups. As a result, the presence of cartilage lesion of ICRS grade 2 or 3 in the lateral compartment of the knee, either subtle or not detected during the preoperative evaluation, would not affect the surgical outcome of MOWHTO. This is a Level IV, therapeutic case series study.

Return to Physical Activity After High Tibial Osteotomy or Unicompartmental Knee Arthroplasty: A Systematic Review and Pooling Data Analysis

BACKGROUND

The 2 most common definitive surgical interventions currently performed for the treatment of medial osteoarthritis of the knee are medial opening wedge high tibial osteotomy (HTO) and medial unicompartmental knee arthroplasty (UKA). Research exists to suggest that physically active patients may be suitably indicated for either procedure despite HTO being historically indicated in active patients and UKA being more appropriate for sedentary individuals.

PURPOSE

To help consolidate the current indications for both procedures regarding physical activity and to ensure that they are based on the best information presently available.

STUDY DESIGN

Systematic review.

METHODS

A search of the literature via the MEDLINE, Embase, and PubMed databases was conducted independently by 2 reviewers in accordance with the PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines. Studies that reported patient physical activity levels with the Tegner activity score were eligible for inclusion. Patient demographics, operative variables, and patient-reported outcome scores were abstracted from the included studies.

RESULTS

Thirteen eligible studies were included, consisting of 401 knees that received HTO (399 patients) and 1622 that received UKA (1400 patients). The patients' mean age at surgery was 48.4 years for the HTO group and 60.6 years for the UKA group. Mean follow-up was 46.6 months (HTO) and 53.4 months (UKA). All outcome scores demonstrated an equal or improved score for activity and knee function regardless of the operation performed. Operative variables during HTO had a larger effect on outcome than during UKA.

CONCLUSION

Patients who underwent HTO were more physically active pre- and postoperatively, but patients undergoing UKA experienced an overall greater increase in their physical activity levels and knee function according to Tegner and Lysholm scores. Activity after HTO may be influenced by operative factors such as the implant used and the decision to include a graft material in the osteotomy gap, although this requires further research. Some studies found that patients were able to return to physical activity postoperatively despite having an age or body mass index that would traditionally be a relative contraindication for HTO or UKA.

Rotational Changes in the Distal Tibial Fragment Relative to the Proximal Tibial Fragment at the Osteotomy Site after Open-Wedge High-Tibial Osteotomy

The present study is aimed at assessing the changes in tibial rotation at the osteotomy site after an open-wedge, high-tibial osteotomy (OWHTO) and analysing the factors that affect rotational changes in the distal tibial fragment relative to the proximal tibial fragment at the same site. This study involved 53 patients (60 knees; 16 males and 37 females) with medial osteoarthritis (OA) who underwent OWHTO and preoperative and 3-month postoperative computed tomography (CT) scans. Rotational angles of the distal tibia were measured using Stryker OrthoMap 3D by comparing preoperative and postoperative CTs. The mean rotational angle yielded an external rotation of 2.9° ± 4.8°. There were 17 knees with internal rotations, 37 knees with external rotations, and one knee with no rotation. The rotational angle significantly correlated with the resultant change in the femorotibial angle (correction angle) and the angle between the ascending and transverse osteotomy lines on the anterior osteotomised surface on which a flange was formed with the distal tibial osteotomised surface (flange angle). The flange angle affected the rotation, but it may have been affected by our surgical technique. The rotational angle did not significantly correlate with the change in the angle of the posterior tibial slope or body mass index. There were significant correlations between the rotational angle and correction angle (r = 0.42, p < 0.05). Additionally, the rotational angle correlated with the flange angle (r = -0.41, p < 0.05).

An Increase in Medial Joint Space Width After Medial Open-Wedge High Tibial Osteotomy Is Associated With an Increase in the Postoperative Weight-Bearing Line Ratio Rather Than With Cartilage Regeneration: Comparative Analysis of Patients Who Underwent Second-Look Arthroscopic Assessment

PURPOSE

To investigate relevant factors influencing increases in medial joint space width (JSW) after medial open-wedge high tibial osteotomy (MOWHTO).

METHODS

Between January 2010 and December 2018, the electronic medical records of consecutive patients who underwent MOWHTO and subsequent second-look arthroscopic assessment at least 12 months after MOWHTO were retrospectively evaluated. The patients were classified into 2 groups according to changes in the medial JSW of the knee at the time of the second-look operation compared with that at baseline before the initial surgical procedure. Various radiographic parameters, arthroscopic findings, and clinical scores were compared between the groups, and regression analysis was performed to identify factors related to increases in medial JSW.

RESULTS

A total of 114 patients were analyzed. In a bivariate analysis, patients who experienced an increase in medial JSW showed a significantly higher postoperative weight-bearing line ratio (WBLR) (P = .008) and a greater proportion of severe preoperative cartilage lesions in the medial compartment of the knee compared with patients with a maintained or reduced medial JSW (P = .035). In terms of clinical scores, patients with an increased medial JSW showed relatively favorable clinical outcomes at the time of the second-look operation. Regression analysis indicated only postoperative WBLR as a relevant factor associated with an increase in medial JSW after MOWHTO (odds ratio, 1.057; P = .01). Additional analysis with patients reclassified according to the postoperative WBLR showed that as the postoperative WBLR increased, the medial JSW increased, without a significant change in the lateral JSW.

CONCLUSIONS

An increase in the medial JSW of the knee joint after MOWHTO appears to be associated with an increase in the postoperative WBLR, not with cartilage regeneration. Obtaining adequate correction so that the postoperative WBLR is within 60% to 70% would be desirable in terms of postoperative changes in the medial JSW, as well as clinical outcomes.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Clinicoradiologic Outcomes of Medial Open-Wedge High-Tibial Osteotomy Are Equivalent in Bone-on-Bone and Non-Bone-on-Bone Medial Osteoarthritis

PURPOSE

(1) To investigate whether patients with bone-on-bone (BOB) medial OA (Ahlback grade 2) had comparable clinical improvement to those with non-BOB arthritis with remaining joint space (Ahlback grades 0/1) after medial open-wedge high tibial osteotomy (MOWHTO); (2) to determine whether the radiological results differ between these 2 groups from 1 month postoperatively to last follow-up ≥2 years later.

METHODS

Data of 132 knees (40 males and 92 females) who underwent MOWHTO were retrospectively reviewed. Preoperative standing anteroposterior radiographs were evaluated according to the Ahlback classification. Patients with Ahlback grade ≤1 were classified as the non-BOB group (group I, n = 88; mean age, 50.5 ± 6.3 years) and those with grade 2 as the bone-on-bone group (group II, n = 44; age, 51.6 ± 5.3 years). Clinical outcomes were assessed using Hospital for Special Surgery (HSS) and Knee Society (KS) functional scores. Medial joint space width (JSW), medial proximal tibial angle (MPTA), and mechanical alignment were considered radiological parameters.

RESULTS

Preoperative clinical scores were significantly lower in patients with BOB arthritis (HSS score: group I, 73.5 ± 10.7 versus group II, 69.2 ± 9.1, P = .026; KS score: group I, 72.9 ± 10.3 versus group II, 63.2 ± 11.6 points, P < .001). However, HSS and KS functional scores improved in both groups without a significant difference at a mean follow-up of 3.4 ± 2.5 and 4.1 ± 3.1 years in groups I and II, respectively (HSS score: 89.2 ± 9.5 versus 89.4 ± 7.3 points, P = .258; KS functional score: 90.1 ± 7.1 versus 87.8 ± 8.9 points, P = .105). Preoperative and postoperative medial JSWs were narrower in group II, but the JSW opening was wider in group II at 1 month after surgery and was maintained until the last follow-up (preoperative, 3.0 ± 0.9 versus 0.0 ± 0.1 mm; 1 month, 3.1 ± 1.0 versus 1.4 ± 0.8; last follow-up, 3.0 ± 1.0 versus 1.4 ± 0.9 mm; P < .001).

CONCLUSION

Patients with BOB medial OA achieved clinical outcomes comparable to those with remaining joint space after MOWHTO. The medial JSW showed a significant increase without OA progression during midterm follow-up in these patients. Therefore, MOWHTO can be an effective treatment choice for symptomatic improvement in middle-aged patients with severe medial OA, if there is no subchondral bone attrition.

LEVEL OF EVIDENCE

III, retrospective comparative study.

Minimally Invasive High Tibial Osteotomy Using a Patient-Specific Cutting Guide

Medial opening wedge high tibial osteotomy (OW-HTO) is an excellent surgical option for patients with varus knee osteoarthritis. This article presents a technique of performing a minimally invasive OW-HTO using a patient-specific cutting guide (PSCG). Preoperative 3-dimensional planning with computed tomography imaging is essential. The correction parameters, the final plate position, as well as the 3-dimensional position of the hinge as well as wedge are verified preoperatively before the PSCG is produced. After exposure with an oblique incision over the posteromedial tibia, the hamstring tendons are released for later re-attachment and the medial collateral ligament is released slightly. The PSCG is then used to perform the OW-HTO with protection of the posterior neurovascular structures by a retractor placed posterior to the medial collateral ligament. The final fixation of the osteotomy is achieved with a low-profile locking plate and a femoral head allograft wedge.

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 of joint-line convergence angle should be considered for accurate alignment correction in high tibial osteotomy

Background

The alignment correction after high tibial osteotomy (HTO) is made both by bony correction and soft-tissue correction around the knee. Change of the joint-line convergence angle (JLCA) represents the soft-tissue correction after HTO, which is the angle made by a tangential line between the femoral condyles and the tibial plateau. We described the patterns of JLCA change and related factors after HTO and investigated the appropriate preoperative planning method.

Methods

Eighty patients who underwent HTO between 2013 and 2016 were included for this retrospective study. Standing, whole-limb radiograph, supine knee anteroposterior (AP) and lateral were measured on the preoperative and postoperative radiographs. The patterns of JLCA changes and related factors were analyzed.

Results

JLCA decreased by a mean of 0.9° ± 1.2° (P < 0.001) after HTO. Sixteen patients (20%, group II) showed a greater JLCA decrease ≥ 2°, while 64 (80%, group I) patients remained in a narrow range of JLCA change < 2°. Group II showed more varus deformity (varus 8.1° vs. varus 4.7° in the mechanical femorotibial angle, P < 0.001), greater JLCA on standing (4.9° vs. 2.1°, P < 0.001), and the difference of JLCA in the standing and supine positions (2.8° vs. 0.7°, P < 0.001) preoperatively compared to group I. The risk of a greater JLCA decrease ≥ 2° was associated with greater preoperative JLCA in the standing position and the difference between the JLCA in the standing and supine positions. Postoperative JLCA correlated better with preoperative JLCA in the supine position than those in the standing position. A preoperative JLCA ≥ 4° or the difference of preoperative JLCA in the standing and supine positions ≥ 1.7° was the cut-off value to predict a large JLCA decrease ≥ 2° after HTO in the receiver operating characteristic (ROC) curve analysis.

Conclusions

Surgeons should consider the effect of the JLCA change during the preoperative planning and intraoperative procedure to avoid unintended overcorrection.

Impact of medial open-wedge high tibial osteotomy for medial compartment osteoarthritis of the knee

BACKGROUND

Most populations worldwide, who are used to squatting and sitting cross-legged for their activities of daily living, largely comprise the lower socioeconomic strata, thus making them candidates for exclusion for total knee arthroplasty. Proximal/high tibial osteotomy (HTO) is a preferred strategy for clinically symptomatic osteoarthritis (OA) with genu varum due to painful medial compartment OA which is not amenable to conservative measures.

AIM

To evaluate the outcomes of medial open-wedge HTO along with autologous bone grafting and buttress plate for the treatment of genu varum due to OA of the knee in a rural population of central India.

METHODS

A total of 65 knees in 56 patients with a mean age of 58.22 ± 5.63 years with genu varum due to intractable painful knee OA were treated with medial open-wedge HTO along with autologous bone grafting and buttress plate osteosynthesis from June 2015 to May 2018. The mean preoperative radiological angle of genu varum was 13.4°. Clinical outcomes were assessed by the range of movement, knee scores, pain scores, and functional scores. Radiographic studies were performed preoperatively and at regular intervals during the follow-up period.

RESULTS

All patients reported pain relief immediately after the osteotomy and during the long-term analysis covering between one to three years. The genu varum angle was overcorrected to approximately four degrees in all patients. There was a loss of reduction by approximately three degrees in all patients at around six weeks postoperatively. Preoperative knee movements were restored in all patients. No major perioperative complications were noted during surgery and postoperative follow-up and the clinical scores were significantly improved during the final analysis which revealed good pain relief.

CONCLUSION

Medial open-wedge HTO is a reliable, safe, practical, physiological, and feasible treatment for populations who are used to increased activity in their occupation and lifestyle and is associated with excellent short-term and long-term results for OA in genu varum knees.

Medium-term survival and clinical and radiological results in high tibial osteotomy: Factors for failure and comparison with unicompartmental arthroplasty

INTRODUCTION

High tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) are two surgical solutions for isolated medial tibiofemoral osteoarthritis. Results depend on preoperative criteria and patient selection, but also on postoperative factors: implant positioning, limb alignment. Factors for HTO survival need identifying to reduce risk of failure requiring total knee arthroplasty (TKA).

HYPOTHESIS

Age, gender, weight, osteoarthritis grade, degree of correction, type of osteotomy, technique and intraoperative complications impact HTO survival.

MATERIAL AND METHOD

As part of a symposium of the French Society of Arthroscopy (SFA), a multicenter retrospective study compared 2 series. The HTO series comprised 488 patients: 153 female (31.4%); mean age, 55.1 years; mean weight, 83.1kg; mean body-mass index (BMI), 28.6. The UKA series comprised 284 patients: 172 female (60.6%); mean age, 64.1 years; mean weight, 75.3kg; mean BMI, 27.6. The main endpoint was comparative survival at 5, 8 and 10 years; secondary endpoints comprised pre- and post-operative hip-knee-ankle (HKA) angle, mechanical femoral angle (mFA) and mechanical tibial angle (mTA), surgical technique, satisfaction, time to and level of return to work, WOMAC and Tegner scores and complications rates. The significance threshold was set at p<0.05; 95% confidence intervals were calculated.

RESULTS

Age>54 years, male gender, BMI>25, medial tibiofemoral wear severity Ahlback ≥3, ≥0.9° varus joint component, HKA correction<8°, postoperative HKA<180° and hinge fracture were significantly associated with poorer survival. There was no impact of type of osteotomy, navigation assistance or postoperative HKA 183-186°. Ten-year survival was 74.3% for HTO and 71% for UKA (non-significant); however, survival curves crossed at 6 years.

CONCLUSION

HTO showed survival and functional results comparable to those of UKA in selected patients when target limb alignment correction was achieved. The present study determined selection criteria. A predictive score for results of either procedure would facilitate decision-making.

LEVEL OF EVIDENCE

IV, retrospective cohort study.

Research trends and hotspots of high tibial osteotomy in two decades (from 2001 to 2020): a bibliometric analysis

BACKGROUND

The purpose of this study is to comprehensively analyze the global application trend of high tibial osteotomy (HTO) and identify promising research hotspots of HTO based on bibliometrics and visual analysis.

METHODS

Publications (articles and reviews) related to HTO from 2001 to 2020 were retrieved from the Web of Science Core Collection database (WOSCC). The country, institution, year, author, journal, average citations per item, H index, title, abstract, keywords of publication, and the top 10 cited articles were extracted and analyzed in detail. The VOSviewer software was used to analyze theco-occurrence of keywords to predict the hotspots of HTO.

RESULTS

A total of 1883 articles were included. In the past 20 years, the number of HTO articles has shown an increasing trend in general. The top 3 countries (the USA, Germany, and South Korea) accounted for 49.547% of all articles published. The USA has the largest number of publications. The University of Western Ontario is the largest contributor. The Knee Surgery Sports Traumatology Arthroscopy is the most influential journal. Professors Saito T and Imhoff AB are the leading scholars who made great achievements in the HTO field. The research direction can be divided into the following 5 clusters: "prognosis and outcome", "HTO combined with cartilage restoration techniques", "animal experimental research", "study on bone union and plate fixation at osteotomy", and "surgical technique research".

CONCLUSION

In terms of the trend of previous years, an increasing number of literatures related to HTO will be published in the future. The USA is a world leader in the field of HTO. South Korea presented great potential in this area. HTO combined with cartilage restoration techniques, postoperative prognosis and outcome, and surgical technique research may be the future hotspots in the field of HTO research.

Relationship between the bony correction angle and mechanical axis change and their differences between closed and open wedge high tibial osteotomy

BACKGROUND

The purpose of this study was to investigate the relationship between the bony correction angle and mechanical axis change and their differences between closed wedge high tibial osteotomy (CWHTO) and open wedge high tibial osteotomy (OWHTO).

METHODS

A total of 100 knees of 89 patients who underwent OWHTO (50 knees) or CWHTO (50 knees) between 2011 and 2015 with a clinical follow-up for 1 year and a radiological follow-up for 1 month were investigated in a case control study. Anteroposterior radiographs of the knee and full-length leg were taken in the standing position using digital acquisition. The femorotibial angle (FTA), % mechanical axis deviation (MAD), % anatomical tibial axis deviation (ATAD), % mechanical tibial axis deviation (MTAD), mechanical medial proximal tibial angle (mMPTA), and joint line convergence angle (JLCA) were measured on preoperative and postoperative radiographs using a dedicated software.

RESULTS

CWHTO resulted in a greater variation between the tibial anatomical and mechanical axes than OWHTO (P <  0.05), and a greater soft tissue correction than OWHTO (P <  0.05). However, no significant difference was found between CWHTO and OWHTO in the ratio of MAD change to the correction angle. When the osteotomy was planned with the same bony correction angle, %MAD passed more laterally in OWHTO than in CWHTO (P <  0.05). These results suggested a lesser valgus bony correction ratio due to greater medial shift of the tibial axis and greater valgus compensation of the soft tissue in CWHTO compared to OWHTO.

CONCLUSIONS

The ratio of mechanical axis shift to the correction angle differed in preoperative planning, but postoperative alignment was comparable between opening wedge and closed wedge high tibial osteotomy.

Recombinant Human BMP6 Applied Within Autologous Blood Coagulum Accelerates Bone Healing: Randomized Controlled Trial in High Tibial Osteotomy Patients

Bone morphogenetic proteins (BMPs) are potent osteogenic proteins that induce new bone formation in vivo. However, their effect on bone healing in the trabecular bone surfaces remains challenging. We evaluated the safety and efficacy of recombinant human BMP6 (rhBMP6) applied within an autologous blood coagulum (ABC) in a surgically created wedge defect of the proximal tibia in patients undergoing high tibial osteotomy (HTO) for varus deformity and medial osteoarthritis of the knee. We enrolled 20 HTO patients in a randomized, placebo-controlled, double-blinded phase I/II clinical trial. RhBMP6/ABC (1.0 mg/10 mL ABC prepared from peripheral blood) or placebo (10 mL ABC containing excipients) was administered into the tibial wedge defects. Patients were followed for 0 to 24 months by clinical examination (safety) and computed tomography (CT) and serial radiographic analyses (efficacy). The results show that there were no detectable anti-rhBMP6 antibodies in the blood of any of the 20 patients at 14 weeks after implantation. During the 24 months of follow-up, there were no serious adverse reactions recorded. The CT scans from defects of patients treated with rhBMP6/ABC showed an accelerated bone healing compared with placebo at 9 weeks (47.8 ± 24.1 versus 22.2 ± 12.3 mg/cm³ ; p = 0.008) and at 14 weeks (89.7 ± 29.1 versus 53.6 ± 21.9 mg/cm³ ; p = 0.006) follow-up. Radiographic analyses at weeks 6 and 24 and months 12 and 24 suggested the advanced bone formation and remodeling in rhBMP6/ABC-treated patients. In conclusion, we show that rhBMP6/ABC at a dose of 100 μg/mL accelerated bone healing in patients undergoing HTO without serious adverse events and with a good tolerability compared with placebo alone. Overall, for the first time, a BMP-based osteogenic implant was examined against a placebo for bone healing efficacy in the trabecular bone surface, using an objective bone mineral density measurement system. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

Can medial stability be preserved after open wedge high tibial osteotomy?

Purpose

This study evaluated the medial joint stability after high tibial osteotomy (HTO) releasing the superficial medial collateral ligament (sMCL) without cutting and repairing.

Methods

Twenty-one patients who performed HTO were enrolled. After an L-shaped incision was made in the pes anserinus, the sMCL was released from the distal portion during surgery. After plate fixation, the sMCL was reattached and the pes anserinus was repaired underneath the plate. Plate removal was performed after 31.1 ± 14.2 months. Before HTO, a valgus force of 40 N was exerted at extension for reference values. Before and after plate removal, a valgus force of 40 N was exerted at extension and at a flexion position of 20°. Medial stability was evaluated by measuring the joint line convergence angle (JLCA).

Results

The JLCAs in the extension state before HTO and plate removal were 1.64° ± 1.15° and 1.83° ± 1.36°, respectively; there was no significant difference (p = 0.198). There was also no significant difference in JLCA before HTO and after plate removal (p = 0.835). There was also no significant difference in JLCA before and after plate removal both at a knee extension and flexion position of 20° (p = 0.348 and p = 0.456, respectively).

Conclusions

Releasing the sMCL without cutting and repairing the pes anserinus underneath the plate during medial open wedge HTO could facilitate the maintenance of medial joint stability.

Changes in lower limb alignment and their effect on the functional outcome after treatment of varus degenerative OA knee by hemicallotasis using modular dynamic HTO fixator

OBJECTIVE

High tibial osteotomy (HTO) is an established procedure to treat medial compartmental osteoarthritis (OA) knee associated with varus deformity. It is well documented that precise correction of deformity and maintenance of correction achieved is important to ensure long term good results. This study was undertaken to record changes in radiological parameters and its effect on the functional outcomes in first two years following HTO done for varus degenerative OA kneeby hemicallotasis technique using HTO fixator.

METHODS

31 patients meeting our inclusion-exclusion criteria who underwent HTO by hemicallotasis method using self-adjusting unilateral HTO fixator were included in the study. Their femoro tibial angle (FTA), mechanical axis %, Insall- Salvati ratio, proximal tibial antero-posterior slope and knee injury and osteoarthritis outcome Score (KOOS) were recorded preoperatively, postoperatively at the time of removal of fixator, at 1 year and at 2 years.

RESULTS

The FTA and mechanical axis significantly improved from a mean of 183.12⁰ and -3.26% respectively preoperatively to 173.38⁰ and 61.81% at the time of removal of fixator but subsequently showed significant deterioration to 176.06⁰ and 57.96% at 1 year and further insignificant deterioration to 176.16⁰ and 57.74 at 2 years. The KOOS improved from mean 56.61 preoperatively to 70.48 at the time of fixator removal and further improved significantly to 85.68 at 1 year but significantly deteriorated to 84.54 at 2 years. The Insall-Salvati ratio, tibial slope showed no significant change throughout the study. Conclusion: Though desired alignment can be achieved by using the fixator, we found a significant deterioration in achieved radiological parameters after removal of fixator adversely affecting the functional outcome which is a matter of concern.

Treatment for Symptomatic Genu Recurvatum: A Systematic Review

Background:

Symptomatic genu recurvatum is a challenging condition to treat. Both osseous and soft tissue treatment options have been reported to address symptomatic genu recurvatum.

Purpose/Hypothesis:

The purpose of this article was to review the current literature on surgical treatment options for symptomatic genu recurvatum and to describe the associated clinical outcomes. We hypothesized that anterior opening-wedge proximal tibial osteotomy (PTO) would be the most common surgical technique described in the literature and that this intervention would allow for successful long-term management of symptomatic genu recurvatum.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, with the inclusion criterion of surgical treatment options for symptomatic genu recurvatum. Recurvatum secondary to polio, cerebrovascular accident, or cerebral palsy was excluded from this review.

Results:

A total of 311 studies were identified, of which 6 studies with a total of 80 patients met the inclusion criteria. Causes of genu recurvatum included physeal arrest; soft tissue laxity; and complications related to fractures, such as prolonged immobilization and malalignment. Mean follow-up times ranged from 1 to 14.5 years postoperatively. There were 5 studies that described anterior opening-wedge PTO, 2 of which used the Ilizarov distraction technique. All 3 studies that used PTO without the Ilizarov technique reported correction of recurvatum and increased posterior tibial slope; 2 of these studies also included subjective outcomes scores, reporting good or excellent outcomes in 70% (21/30) of patients. Of the studies that used the Ilizarov technique, both reported correction of recurvatum and increased posterior slope from preoperative to postoperative assessments. Both of these studies reported good or excellent subjective outcomes postoperatively in 89.5% (17/19) of patients. Additionally, 1 study successfully corrected recurvatum by performing a retensioning of the posterior capsule to address knee hyperextension, although follow-up was limited to 1 year postoperatively.

Conclusion:

Anterior opening-wedge PTO, with or without postoperative external fixation with progressive distraction, was found to be a reliable surgical treatment for symptomatic genu recurvatum. After surgical management with PTO, patients can expect to achieve correction of knee hyperextension, restoration of a more posterior tibial slope, and increased subjective outcome scores.

Preoperative Medial Meniscal Extrusion Is Associated With Patient-Reported Outcomes After Medial Opening Wedge High Tibial Osteotomy

BACKGROUND

Although the medial compartment continues to sustain some loading after medial opening wedge high tibial osteotomy (MOWHTO) in varus-deformed knees, no studies have examined the relationship between medial meniscal extrusion (MME) and patient-reported outcome measures after MOWHTO.

PURPOSE

To examine whether compartmental baseline MME was associated with patient-reported outcome measures after MOWHTO.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This retrospective study was composed of 149 MOWHTOs in 147 patients with clinical and radiological assessments. Patients were grouped according to severity of MME in the medial compartment at the time of surgery. MME was categorized into 4 groups according to MOAKS (MRI [magnetic resonance imaging] Osteoarthritis Knee Score) criteria and relative value of MME. We compared preoperative characteristics, including Kellgren-Lawrence (KL) grading scale, meniscal tear pattern, and postoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscores. Associations between extent of MME and WOMAC subscores at postoperative 1 and 2 years were assessed with generalized linear models.

RESULTS

Pattern of meniscal tear (P < .05) and KL grade (P < .05) were associated with MME. Patients with KL grades 3 and 4 at the time of surgery had significantly greater MME than those with KL grade 2 (P < .05). When patients were divided into 4 groups according to MOAKS criteria at the time of surgery, there were significant differences in WOMAC pain scores among groups at 1 and 2 years after the operation (all P < .05). The WOMAC function score also differed among groups at postoperative 1 year (P < .05) but not postoperative 2 years (P > .05). When patients were divided into 4 groups according to relative MME at the time surgery, the WOMAC pain score differed significantly among groups at postoperative 1 and 2 years (all P < .05). Analysis of WOMAC pain score as the dependent variable in multivariate analyses revealed that severity of absolute and relative MME and KL grade were independent predictors of worse WOMAC pain score at postoperative 1 and 2 years (all P < .05).

CONCLUSION

Greater preoperative MME at the time of surgery was associated with inferior patient-reported outcomes, especially pain, in patients with MOWHTO at 1 and 2 years after surgery.

Ultrasonographic evaluation of the patellar tendon length and elasticity after open-wedge high tibial osteotomy: A comparison with radiological and clinical parameters

BACKGROUND

The aim of this study was to evaluate the length and elasticity of the patellar tendon after open-wedge high tibial osteotomy (OWHTO).

METHODS

This case-controlled, analytical study included patients who underwent unilateral OWHTO operation and a control group. The length, thickness, strain elastography, and strain ratio of the patellar tendon were measured. The outcome measures were the Insall-Salvati Index (ISI), Blackburne-Peel Index (BPI), Caton Index (CI), the International Knee Documentation Committee Score (IKDC), Oxford Knee Score (OKS) and Knee Injury and Osteoarthritis Outcome Score (KOOS), Ahlbäck classification, and mechanical axis. Elasticity of the patellar tendon obtained by strain elastography were graded as follows; hardest or hard tissue, intermediate tissue, and soft tissue.

RESULTS

The patellar tendon length was significantly shorter and patellar tendon thickness was significantly greater on the operated side compared with the values of the non-operated side and the control group (P<0.001 for all). Intermediate tissue was the most common elasticity grade (77%) for strain elastography on the operated side. Hardest tissue was the most common elasticity grade on the non-operated side of the patients (49.1%) and of the control group (70.0%). Patellar tendon length was correlated positively with IKDC, OKS, and KOOS values and patellar tendon thickness and strain ratio were correlated negatively with IKDC, OKS, and KOOS values.

CONCLUSION

The patellar tendon seems to be shortened and thickened, with reduced stiffness after OWHTO. The ultrasound parameters are also associated with functional outcomes.

Open Versus Closing Wedge Osteotomy and Application to Mandibular Reconstruction

PURPOSE

To review the specific techniques of closing wedge osteotomy and open osteotomy, compare their clinical and radiographic outcomes, and apply these findings to mandibular reconstruction.

METHODS

A thorough review of the otolaryngology, facial plastic and reconstructive surgery, oral and maxillofacial surgery, and orthopedic surgery literature was conducted in the Ovid MEDLINE, EMBASE, and Google Scholar databases using the terms 'osteotomy' and 'mandibular reconstruction.'

RESULTS

Traditionally, open osteotomies were thought to result in greater rates of malunion. However, multiple meta-analyses within the orthopedic literature have refuted this. Closing wedge osteotomies, on the other hand, may increase the chance of damaging a perforator. Again, no studies have evaluated the relationship between type of osteotomy and flap survival or wound healing. The particular type of osteotomy performed often depends on the type of osseous flap being utilized.

CONCLUSIONS

Open osteotomies are a viable and even preferred alternative, particularly in flaps without consistent perforators, such as scapular free flaps.

A novel device for greater precision and safety in open-wedge high tibial osteotomy: cadaveric study

INTRODUCTION

The complications of the open-wedge osteotomy technique (slope, hypo- and hypercorrection and fractures) are related to difficulties in the control of the open-wedge angle during surgery.

MATERIALS AND METHODS

In this cadaveric study, we evaluated the safety and precision of a novel system, the Realignment High Control System (RHC), in the correction of knee mechanical axis and slope. The RHC has a fixation plate coupled to a dynamic device that opens the osteotomy continuously, allowing plate fixation before osteotomy wedge opening.

RESULTS

All procedures were easily performed, with no fractures. The openings equaled the indicated by the navigation system for 7.5° and 10°, and for 5°, there was a statistically, although not clinically significant, difference of 0.6°. The slope shown by the RHC setting and in the navigation system was significantly different for the 10° setting only, with a mean difference of 0.563°.

CONCLUSIONS

RHC facilitates the surgical technique of high tibial osteotomy, with gradual wedge opening, precise correction of the mechanical axis, and appropriate control of the tibial slope, even with larger openings.

Early experience of lateral hinge fracture during medial opening-wedge high tibial osteotomy: incidence and clinical outcomes

PURPOSE

Lateral hinge fracture (LHF) during a medial opening-wedge high tibial osteotomy (MOWHTO) is considered to be the main cause of instability, further displacement, loss of correction, malunion, and nonunion. The purposes of this study were to evaluate whether the incidence of LHFs during MOWHTOs has decreased as the number of cases performed over time has increased, and whether the radiographic and clinical outcomes of patients with LHFs were worse than those of patients without LHFs.

MATERIALS AND METHODS

During the period of July 2013 to January 2017, 132 MOWHTOs were performed by a single surgeon using a locking plate (TomoFix^®, DePuySynthes, Solothurn, Switzerland) for the treatment of medial compartment osteoarthritis, with LHFs postoperatively detected in 32 knees (24.2%). To evaluate trends in the incidence of LHFs occurring during MOWHTOs over time, all 132 cases were divided chronologically into four groups of 33 cases and compared. The time for bony union and loss of correction were compared between the LHF group and the non-LHF group using an osteotomy filling index, hip-knee-ankle (HKA) angles, medial proximal tibial angles (MPTA), weight-bearing line (WBL) ratios, and posterior tibial slope (PTS) angles on radiographs. Clinical outcomes were also compared using the Knee Society Scores (KSS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores 1 year post-surgery.

RESULTS

The incidence of LHFs in each group of 33 cases did not decrease over time (21.2%, 27.3%, 24.2%, and 24.2%, respectively, p = 0.954). The time to union was significantly different between the non-LHF group (5.0 months) and the LHF group (7.3 months) (p < 0.001). However, there were no immediate or 1-year postoperative differences in the HKA angles, MPTAs, WBL ratios, or PTS angles between the non-LHF and LHF groups (all p > 0.05). The KSS and WOMAC scores were significantly improved in both groups (all p < 0.001) 1 year post-surgery, without any differences between the groups (p = 0.997 and p = 0.122, respectively).

CONCLUSIONS

LHFs during MOWHTO procedures occurred consistently, with a similar incidence over time. Although patients with LHFs required more time to bony union, they showed similarly favorable radiographic and clinical results as the patients without LHFs 1 year after surgery.

The Joint Angle Tool for Intraoperative Assessment of Coronal Alignment of the Lower Limb

Aim

Presentation of the joint angle tool (JAT), a low-cost goniometer for intraoperative assessment of the lower limb alignment.

Background

Intraoperative assessment of coronal alignment is important when performing corrective osteotomies around the knee and ankle, limb lengthening, and trauma surgery. JAT provides surgeons with information about the anatomic and mechanical axes intraoperatively based on true anteroposterior radiographs.

Technique

JAT consists of pre-printed joint orientation angles of the anatomic and mechanical axis including normal variations on a plastic sheet. It is placed on the screen of the image intensifier after obtaining a true anteroposterior image. The pre-printed joint orientation angles can assist the surgeons intraoperatively in achieving the pre-planned axis correction. Here, its feasibility is demonstrated in four cases.

Conclusion and clinical significance

JAT is a modified goniometer that allows intraoperative assessment of the mechanical and anatomic axis. JAT is applicable throughout the entire surgical procedure irrespective of the method of internal fixation and may provide additional reassurance of correct alignment. JAT consists of a plastic sheet with printed joint orientation angles and their normal variation. JAT is freely available from profeedback.dk/JAT/JAT.pdf for use and modification according to the Creative Commons license (CC BY-SA 4.0) if this paper is attributed.

How to cite this article

Abood AA-H, Petruskevicius J, Vogt B, et al. The Joint Angle Tool for Intraoperative Assessment of Coronal Alignment of the Lower Limb. Strategies Trauma Limb Reconstr 2020;15(3):169-173.

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.

Superficial Medial Collateral Ligament Reattachment During High Tibial Osteotomy: Regulate Tension, Preserve Stability!

High tibial osteotomy (HTO) is a commonly performed surgical procedure. Although it is well-known that the superficial medial collateral ligament (sMCL) should be released during HTO, there is still no agreement on performing its reattachment. Considering the function of the sMCL, after its release during HTO, increased medial joint instability may be expected. We present a technique for sMCL reattachment that prevents medial gapping development and maintains nearly native pressure on the medial compartment of the knee joint by matching the tension on the sMCL to the size of the osteotomy gap. This technique is suitable for any correction angle.

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.

Opposite hinge fractures in high tibial osteotomy: a displacement subtype is more critical than a fracture type

PURPOSE

Analysis of the structure of the fractures of opposite hinge (FOH) after angle-stable closed-wedge (CW) and open-wedge (OW) high tibial osteotomy (HTO), and their influence on the development of tibial pseudarthrosis.

METHODS

187 CW and 94 OWHTOs were analyzed retrospectively. The FOHs in the OWHTO were classified according to Takeuchi, and in the CWHTO-according to the own classification with two types (depending on the direction of FOH). FOHs in both techniques were also subdivided into three subtypes according to displacement (A-non-displaced, B-primarily displaced, C-secondarily displaced). The statistical analysis included correlation analysis and logistic regression.

RESULTS

FOHs were found in 81 (43.3%) CW and 39 (41.2%) OWHTOs. The stable type 1 fractures predominated in OWHTO (76.9 vs. 42%, p < 0.001), the unstable type 2 FOHs prevailed in CWHTO (58 vs. 17.9%, p < 0.001). The tibial pseudarthrosis rate was higher with type 1 (20 vs. 12.9%, n.s.) and subtype A (16.7 vs. 6.8%, p = 0.048) FOHs in OWHTO, and with type 2 (20 vs. 0%, p < 0.001) and subtypes B (25 vs. 0%, p < 0.001) and C (29.4 vs. 25%, n.s.) in CWHTO (without FOHs 0.9% in CW and 1.8% in OWHTO, n.s.). Relevant correlations were detected between the pseudarthrosis rate and fracture type only in CWHTO (ρ_s = 0.298, p < 0.001, OR 24.87 for type 2) and displacement subtype in both groups (for subtype C: ρ_s = 0.345, p < 0.001, OR 43.75 and ρ_s = 0.231, p = 0.02, OR 18.0, respectively).

CONCLUSIONS

The unstable FOH types were more common in CWHTO. The displacement subtype was more predictive for the development of tibial pseudarthrosis than the fracture type, especially in OWHTO. The secondarily displaced FOHs (subtype C) represented the highest risk for the occurrence of pseudarthrosis in both techniques.

Patients' expectations of osteotomies around the knee are high regarding activities of daily living

PURPOSE

This study was conducted to investigate patients' expectations on high tibial osteotomies, distal femur osteotomies, and double-level osteotomies in different health-related domains. It was hypothesized that expectations are high in terms of capacity to work, pain relief, and restoring knee function.

METHODS

A total of 264 patients (age 47 years ± 11 years) were enrolled in this study from March 2015 until May 2016 in seven specialized orthopaedic surgery departments. Data were collected via the Knee injury and Osteoarthritis Outcome Score, the Hospital for Special Surgery-Knee Surgery Expectations Survey, and a ten-item (non-validated) questionnaire to specifically ask about expectations of osteotomies around the knee 24-48 h prior to surgery. In addition, self-efficacy was assessed. Parametric tests were used to test the hypothesis.

RESULTS

Knee injury and Osteoarthritis Outcome Score test results showed that all patients suffered because of their knee impairments prior to surgery. All participants had high expectations in all aspects regarding the surgical outcome: on a four-point Likert scale ranging from 1 (very important) to 4 (not important), all mean values were between 1.2 and 1.7. For patients who had a demanding physical work, the ability to keep a stressful working posture was more important than for other patients (i.e. to kneel, to squat). Furthermore, preoperative lower quality of life was associated with higher expectations concerning improving the ability to walk, to achieve improvements in activities of daily living and social well-being.

CONCLUSIONS

Patients' expectations of osteotomies around the knee are high in terms of capacity to work, pain relief, and restoring functions. The natural course of osteoarthritis and the potential need for conversion to TKA were underestimated by a substantial proportion of the study population. However, the expectation regarding survival rate is in line with the reported literature. The results of this study should assist surgeons in discussing realistic expectations when considering and counselling patients regarding osteotomies around the knee. This may help to clarify realistic expectations preoperatively and ultimately improve patients' satisfaction.

LEVEL OF EVIDENCE

Therapeutic study, Level II.

Patient reported outcomes after high tibial osteotomy show comparable results at different ages in the mid-term to long-term follow-up

BACKGROUND

Few studies have evaluated the impact of age on patient-reported outcomes in the long-term follow-up after high tibial valgus osteotomy (HTO). The purpose of this study is to assess the association between age at surgery and patient-reported clinical outcomes in the mid-term to long-term follow-up of HTO.

MATERIALS AND METHODS

We mailed the 2011 Knee Society score (KSS) questionnaires to 234 consecutive patients (295 knees) who had undergone closing-wedge HTO, and 158 patients (202 knees, 68.5%) returned a completed questionnaire. The cohort was divided into two groups depending on the age at the time of surgery, and pairs matched the follow-up period and sex was created. The mean follow-up period was approximately 12 years. KSS scores at the final follow-up were compared between two groups using the Student t test and chi-square test, and the survival rates were calculated using Kaplan-Meier survival curves.

RESULTS

The symptom, satisfaction, and expectation scores were not significantly different between the ≤64-year-old patients and ≥65-year-old patients. The functional activities score was significantly lower in older patients than in younger patients. The overall survival rates of HTO were 99.1 ± 0.4% at 5 years, 94.4 ± 1.2% at 10 years, and 84.6 ± 2.7% at 15 years. There was no significant difference in the survival rate after HTO between the two groups divided by the age (p = 0.602).

CONCLUSIONS

Pain relief and satisfaction after HTO in older patients were comparable to those in younger patients in the mid-term to long-term follow-up, although the functional activity was affected by age.

Coronal tibiofemoral subluxation is a risk factor for postoperative overcorrection in high tibial osteotomy

BACKGROUND

Severe tibiofemoral (TF) subluxation > 10 mm is a contraindication for high tibial osteotomy (HTO). However, the relationship between the degree of preoperative TF subluxation at < 10 mm and postoperative radiographic/clinical outcomes remains unclear.

METHODS

Sixty-seven patients who underwent open wedge HTO with a planned postoperative mechanical femorotibial angle (mFTA) of three degrees valgus were retrospectively studied. The minimal subluxation (MIN) group included 39 patients with TF subluxation < 5 mm, while the moderate subluxation (MOD) group included 28 patients with TF subluxation of five to 10 mm. The preoperative and one-year postoperative mFTA, TF subluxation, medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), preoperative Kellgren-Lawrence (K-L) grade and varus-valgus laxity were evaluated. Clinical scores and pain visual analogue scale (VAS) were also analyzed.

RESULTS

The mean preoperative TF values in the MIN and MOD groups were 3.1±1.0 mm and 6.7±1.6 mm (mean±standard deviation, p < 0.001), respectively, with no significant difference in K-L grades. The MIN group demonstrated a significantly smaller varus preoperative mFTA (p < 0.001), larger MPTA (p = 0.011), smaller JLCA (p = 0.004), and less varus laxity (p = 0.023). Postoperative TF subluxation, MPTAs, and JLCAs did not differ significantly between the two groups, while the postoperative mFTA was significantly different (p = 0.001), with unintended overcorrection in the MOD group. No significant difference in clinical scores and VAS were observed.

CONCLUSIONS

After HTO, compared to patients with TF subluxation < 5 mm, patients with TF subluxation of five to 10 mm were more likely to demonstrate unintended valgus overcorrection on one-year postoperative radiography.

Patient Evaluation and Indications for Osteotomy Around the Knee

Osteotomy is recognized as a knee joint-preserving surgical procedure to treat frontal and/or sagittal plane malalignment with or without associated instability. This article outlines the preoperative clinical and imaging assessments of prospective patients undergoing osteotomy. In addition, indications and contraindications as well as surgical planning are presented.

High Tibial Osteotomy and Anterior Cruciate Ligament Reconstruction/Revision

High tibial osteotomy (HTO) may be performed in association with anterior cruciate ligament (ACL) reconstruction/revision in patients with medial osteoarthritis, varus malalignment, and anterior instability. Furthermore, it may be performed in patients with varus alignment and increased posterior tibial slope (exceeding 12°), because it is related to an increased risk for ACL failure. There are different techniques to perform HTO, and consequently, a concomitant HTO and ACL reconstruction/revision. This article describes the indication, surgical techniques, and outcomes of concomitant HTO and ACL reconstruction/revision.

Medium- and long-term results of high tibial osteotomy in patients with primary and secondary knee osteoarthritis with varus deformity

The most common operation for knee osteoarthritis (OA) is total knee arthroplasty (TKA); however, the latter is associated with the development of severe complications. This was the reason for the revival of the interest of orthopedic traumatologists in high tibial osteotomy (HTO), the essence of which is to transfer the load away from the affected medial part of the knee joint (KJ) to the intact lateral one.

Objective: to evaluate the medium- and long-term results of open-wedge (OW) HTO in primary and secondary I–III stage knee OA.

Patients and methods. The Laboratory of Orthopedic Rheumatology and Rehabilitation, V.A. Nasonova Research Institute of Rheumatology, performed 10 OW HTOs in 9 patients in 2005 to 2009 and 21 more OW HTOs in 19 patients in 2014 to 2018 (a total of 31 operations). The male/female ratio was 2.5:1. The mean age of the patients was 57.6±12.5 years; the body mass index (BMI) was 28.5±3.6 kg/m2 ; the correction angle was 11.7±2.5°. Preoperative planning was performed using the Miniaci method; the X-ray stage of knee OA was evaluated according to the Kellgren–Lawrence classification. OW HTO was carried out. For assessment of its results, the investigators determined the degree of pain using a visual analogue scale (VAS) and the KJ status by the Knee Society Score (KSS) scale. The results were assessed at one (n=31), 3.5±0.6 (n=28), and 8.5±1.3 (n=10) years.

Results and discussion. There was a tendency to worsen surgical results over time. The mean VAS values for pain at 1, 3.5, and 8.5 years were as follows: 9.8±10.3; 21.2±16.2 and 38±15.5 mm, respectively. In the same periods, the KSS functional scores were 83.6±14.8, 85.2±12.6, and 80.5±14.2; the objective scores were 80.7±8.5, 75.2±12.7, and 67.8±16.3. There was a strong correlation between the severity of pain and the functional and objective KSS scores (-0.78, -0.81 years, and -0.91 at 1, 3.5, and 8.5 years, respectively; p<0.05). At 3.5±0.6 years, the survival rate after OW HTO was 96.6%. None of the patients examined at 8.5±1.3 years after OW HTO needed TKA. The surgical result was studied in 2 patients at 14 years; one patient underwent TKA, the other refused surgical intervention, the result was satisfactory.

Conclusion. OW HTO has limited indications for use. However, in patients who are allowed to undergo this operation, pain syndrome can be relieved, by maintaining and/or improving KJ function; in most cases, TKA can be delayed for more than 10 years. 

Long-term survival is similar between closed-wedge high tibial osteotomy and unicompartmental knee arthroplasty in patients with similar demographics

PURPOSE

Long-term clinical and radiographic results and survival rates were compared between closed-wedge high tibial osteotomy (HTOs) and fixed-bearing unicompartmental knee arthroplasty (UKA) in patients with similar demographics.

METHODS

Sixty HTOs and 50 UKAs completed between 1992 and 1998 were retrospectively reviewed. There were no significant differences in pre-operative demographics. The mean follow-up period was 10.7 ± 5.7 years for HTO and 12.0 ± 7.1 years for UKA (n.s.). The Knee Society knee and function scores, WOMAC, and range of motion (ROM) were investigated. The mechanical axis and femorotibial angle were evaluated. Kaplan-Meier survival analysis was performed (failure: revision to TKA) and the failure modes were investigated.

RESULTS

Most of the clinical and radiographic results were not different at the last follow-up, except ROM; ROM was 135.3° ± 12.3° in HTO and 126.8° ± 13.3° in UKA (p = 0.005). The 5-, 10-, 15-, and 20-year survival rates were 100%, 91.0%, 63.4%, and 48.3% for closed-wedge HTO, respectively, and 90.5%, 87.1%, 70.8%, and 66.4% for UKA (n.s.). The survival rate was higher than that for UKA until 12 years post-operatively but was higher in UKAs thereafter, following a remarkable decrease in HTO. The most common failure mode was degenerative osteoarthritic progression of medial compartment in HTO and femoral component loosening in UKA.

CONCLUSIONS

Long-term survival did not differ significantly between closed-wedge HTO and fixed-bearing UKA in patients with similar pre-operative demographics and knee conditions. The difference in post-operative ROM and failure mode should be considered when selecting a procedure.

LEVEL OF EVIDENCE

III.

Preliminary study on a novel minimally invasive extra-articular implant for unicompartmental knee osteoarthritis

The purpose of this research was to study the efficacy of a novel implant for osteoarthritic knees. This implant is designed to eliminate excessive loads through the knee and to provide suitable conditions for possible tibiofemoral cartilage repair. The implant was designed for the medial side of the knee joint. Finite Element Analysis (FEA) was performed for an extended knee position of the knee joint. Von Mises stress and contact pressure distributions on the medial and lateral compartments were investigated as well as stress distributions throughout the implant's plates. Comparison of FEA results with and without the implant showed that the maximum von Mises stress and contact pressure experienced by the femoral cartilage were reduced by 40% and 35%, respectively, after introducing the implant. Furthermore, after attaching the implant, the femur was slightly abducted and more stress and pressure were perceived in the lateral compartment compared to the model without implant. The maximum von Mises stress in the implant (96 MPa) was far lower than the yield strength of Ti-6Al-4V (∼900 MPa), the selected material for manufacturing the implant. According to the above points, this initial study shows promise for the new prosthesis.

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).