The use of navigation in medial opening wedge high tibial osteotomy can improve tibial slope maintenance and reduce radiation exposure

Influence of Increased Joint Line Obliquity on Survivorship After Lateral Closing-Wedge High Tibial Osteotomy

BACKGROUND

Although high tibial osteotomy (HTO) has emerged as a powerful intervention for treating symptomatic medial osteoarthritis and varus malalignment, it can result in an increase in knee joint line obliquity (KJLO) in the frontal plane. Limited current evidence hinders understanding of the effect of increased KJLO on HTO survivorship.

PURPOSE

To investigate the influence of KJLO and other potential risk factors on the survivorship of lateral closing-wedge HTO.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients with symptomatic medial knee osteoarthritis and varus malalignment treated with lateral closing-wedge HTO at a single hospital were screened with a minimum follow-up of 5 years. HTO survival rate was assessed using Kaplan-Meier survival analysis. The influence of postoperative increased KJLO (medial proximal tibial angle ≥95°), age (≥55 years), sex (female), preoperative malalignment (hip-knee-ankle angle ≥10° of varus), postoperative untargeted alignment (hip-knee-ankle angle <2° or >6° of valgus), and preoperative osteoarthritis severity (Kellgren-Lawrence grade ≥3) on survivorship of HTO was evaluated using Cox regression analysis. A failure of HTO was defined as a conversion to total knee arthroplasty (TKA).

RESULTS

A total of 410 patients (463 knees) were included, with a mean follow-up of 13.0 years (range, 5.0-18.1 years) and a mean survival time of 11.2 years (range, 1.2-18.1 years) for patients who reached the endpoint of TKA. HTO survival rates at 5, 10, and 15 years postoperatively were 91%, 78%, and 60%, respectively. Multivariate Cox regression analysis showed no significant difference in survivorship between patients with increased KJLO and those with acceptable KJLO (178 vs 285 knees; hazard ratio [HR], 0.8; 95% CI, 0.6-1.1; P = .148), with no significant between-group difference observed in the mean follow-up length (12.9 ± 3.0 years vs 13.1 ± 3.3 years; P = .105). Female sex (HR, 2.0; P < .001) and postoperative untargeted alignment (HR, 1.6; P = .003) were risk factors for a conversion to TKA.

CONCLUSION

Increased postoperative KJLO (medial proximal tibial angle ≥95°) had no significant influence on the survivorship of lateral closing-wedge HTO. Men demonstrated superior survival outcomes compared with women, and it was important to achieve a targeted postoperative alignment (HKA 2°-6° of valgus) to ensure favorable HTO survivorship.

Preoperative Hindfoot Alignment and Outcomes After High Tibial Osteotomy for Varus Knee Osteoarthritis: We Walk on Our Heel, Not Our Ankle

UPDATE

This article was updated on May 15, 2024 because of previous errors, which were discovered after the preliminary version of the article was posted online. On page 898, in the section entitled "Materials and Methods," the sentence that had read "The WBL ratio of the knee joint was defined as the point where the GA or MA passed through the width of the tibia and intersected a line from the center of the femoral head to the center of the calcaneus (for the GA) or talus (for the MA), with the medial edge defined as 0% and the lateral edge as 100%." now reads "The WBL ratio of the knee joint was defined as the point where the GA or MA passed through the width of the tibia and intersected a line from the center of the femoral head to the lowest point of the calcaneus (for the GA) or the center of the talus (for the MA), with the medial edge defined as 0% and the lateral edge as 100%." Likewise, in the legend for Figure 3 on page 899, the sentence that had read "Depiction of the ground mechanical axis (GA), defined as the line (represented by the solid red line) from the center of the femoral head to the ground reaction point at the center of the calcaneus, passing lateral to the traditional mechanical axis (MA; represented by the dashed red line)." now reads "Depiction of the ground mechanical axis (GA), defined as the line (represented by the solid red line) from the center of the femoral head to the ground reaction point at the lowest point of the calcaneus, passing lateral to the traditional mechanical axis (MA; represented by the dashed red line)." Finally, on page 903, "HKA" was changed to "HKA angle" in Table III.

BACKGROUND

The hip-to-calcaneus axis, previously known as the ground mechanical axis (GA), ideally passes through the center of the knee joint in the native knee. The aim of this study was to elucidate, with use of hip-to-calcaneus radiographs, changes in knee and hindfoot alignment and changes in outcomes following high tibial osteotomy (HTO).

METHODS

We reviewed the records for 128 patients who underwent HTO between 2018 and 2020. Patients were stratified into 2 groups, a hindfoot valgus group (n = 94) and a hindfoot varus group (n = 34), on the basis of their preoperative hindfoot alignment. The hindfoot alignment was evaluated with use of the hindfoot alignment angle (HAA). To evaluate lower-limb alignment, full-length standing posteroanterior hip-to-calcaneus radiographs were utilized to measure 4 radiographic parameters preoperatively and 2 years postoperatively: the hip-knee-ankle (HKA) angle, hip-knee-calcaneus (HKC) angle, and the weight-bearing line (WBL) ratios of the mechanical axis (MA) and GA.

RESULTS

The mean HAA improved significantly from 5.1° valgus preoperatively to 1.9° valgus postoperatively in the hindfoot valgus group (p < 0.001). In contrast, in the hindfoot varus group, the HAA showed no meaningful improvement in the coronal alignment of the hindfoot following HTO (p = 0.236). The postoperative mean HKC angle in the hindfoot varus group was 2° more varus than that in the hindfoot valgus group (1.0° versus 3.0°; p = 0.001), and the GA in the hindfoot varus group passed across the knee 8.0% more medially than that in the hindfoot valgus group (55% versus 63% from the most medial to the most lateral part of the tibial plateau). The hindfoot varus group had worse postoperative clinical outcomes than the hindfoot valgus group in terms of the mean Knee injury and Osteoarthritis Outcome Score for pain and American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Score.

CONCLUSIONS

Although our findings did not provide sufficient evidence to establish clinically relevant differences between the groups, they indicated that the group with a preoperative fixed hindfoot varus deformity had a higher rate of undercorrection and worse clinical outcomes, especially pain, following HTO. Therefore, modification of the procedure to shift the GA more laterally may be required for these patients.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Does Generalized Joint Laxity Affect Postoperative Alignment and Clinical Outcomes Following Medial Opening-Wedge High Tibial Osteotomy?

BACKGROUND

The purpose of this study was to investigate whether generalized joint laxity affects the postoperative alignment and clinical outcomes of medial opening-wedge high tibial osteotomy (MOWHTO).

METHODS

A total of 198 patients who underwent MOWHTO was divided into two groups according to absence or presence of generalized joint laxity. Generalized joint laxity was measured using the Beighton and Horan criteria, and a score of 4 or more out of 9 was defined as generalized joint laxity. A weight bearing line (WBL) ratio of 55% to 70% was considered an acceptable postoperative lower limb alignment range; WBL over 70% was defined as overcorrection and less than 55% as undercorrection. The WBL ratio was investigated before and 2 years after surgery, and the Western Ontario McMaster University Osteoarthritis Index scale score (WOMAC) was evaluated for patient-reported outcomes (PRO) of MOWHTO. There were 147 (73.7%) patients in the nongeneralized joint laxity group and 51 (26.3%) in the generalized joint laxity group. Preoperatively, there was no difference between the two groups in hip-knee-ankle (HKA) angle or WBL ratio (all P > .05).

RESULTS

At 2 years postoperatively, the generalized joint laxity group showed significantly higher HKA angle and WBL ratio than the nongeneralized joint laxity group (all P < .05). There was a significant difference in the distribution ratio of undercorrection, normocorrection, and overcorrection patients between the two groups (P < .05). There were no differences between the two groups in preoperative and postoperative WOMAC scores (all, P > .05).

CONCLUSION

The generalized joint laxity significantly affected postoperative over correction of alignment following MOWHTO. However, there was no significant difference in PRO between the patients who did and did not have generalized joint laxity after MOWHTO until 2 years.

Comparison of computer-assisted navigated technology and conventional technology in high tibial osteotomy (HTO): a meta-analysis

BACKGROUND

Though some studies have reported navigated high tibial osteotomy (HTO) is a useful procedure to correct knee deformity. There is still great controversy whether navigated HTO can achieve better accuracy of limb alignment and greater clinical outcomes. Current meta-analysis was conducted to investigate whether better radiographic outcomes and clinical outcomes could be acquired in navigated HTO compared with the conventional procedure.

METHOD

We conducted a literature search in the electronic databases, including Medline, Embase, the Cochrane Library, and Web of Science. We identified studies published before August 2020. We also checked the references of the related articles for any relevant studies. We strictly followed the Preferred Reporting Items for Systematics reviews and Meta-Analysis (PRISMA) guidelines in this review. This research was performed using Review Manager 5.4 software.

RESULTS

Fourteen articles were included, involving 1399 knees. Our meta-analysis indicated that patients undergoing navigated HTO had significantly better outcomes in outliers of aimed limb alignment (RD=-0.24, 95% CI: =-0.34 to -0.13, p < 0.01), outliers of aimed tibial posterior slope (TPS) (RD=-0.41, 95% CI: -0.51 to -0.30, p < 0.01), Range of Motion (ROM) (MD = 6.37, 95%CI: 0.83-11.91, p = 0.02), and American knee society knee score (AKS knee score) (MD = 3.88, 95%CI: 1.37-6.39, p = 0.002). No significant differences were found in Lysholm score (MD = 1.30, 95%CI: -0.31 to 2.90, p = 0.11), American knee society function score (AKS function score) (RD = 1.42, 95%CI: -0.15 to 2.99, p = 0.08), complications (RD=-0.01, 95% CI: = -0.05 to 0.04, p = 0.77), delayed union (RD=-0.01, 95% CI: = -0.02 to 0.03, p = 0.59), and reoperation (RD = 0, 95% CI: -0.09 to 0.10, p = 0.98) between the two groups. The operation time in the navigated group was 15.46 min longer than in the conventional group.

CONCLUSION

Navigated HTO provided more accurate and reproducible radiographic outcomes in the correction of the malalignment than conventional techniques, and there is no difference in the risk of complications compared with conventional HTO. However, it is unclear whether navigation HTO can achieve better clinical results. More randomized controlled trials (RCTs) with high quality, large sample size, and sufficient follow-up period are required.

Clinical efficacy and feasibility of laser correction technology with an ordinary laser pen and surgical instrument box in open-wedge high tibial osteotomy

Background

The clinical outcomes of open-wedge high tibial osteotomy (OWHTO) for medial knee osteoarthritis primarily depend on the corrective precision. The present study aimed to determine the efficacy and feasibility of laser correction technology with an ordinary laser pen and surgical instrument box.

Methods

This prospective and randomized trial included 71 patients randomly divided into laser (n = 36) and traditional groups (n = 35). In the laser group, the hip centre, knee (Fujisawa point), and ankle centre were located preoperatively using the surgical instrument box lid. The leg was aligned with an ordinary laser pen. In the traditional group, the lower limb alignment was corrected by a metal cable. Radiation exposure, operative time, and rate of outliers (lower limb force line does not pass through 62–66% of the lateral tibial plateau) were evaluated. The visual analogue scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were recorded. After 24 months, the femoral tibial angle (FTA), medial proximal tibial angle (MPTA), and posterior slope angle (PSA), were recorded. The Kaplan-Meier method was used to evaluate the survival time of affected knees, and postoperative complications were recorded.

Results

The radiation exposure, operative time and rate of outliers were lower in the laser correction group (P < 0.05). Six months postoperatively, the VAS and WOMAC scores were significantly improved in both groups (P < 0.001). At 24 months, the FTA, MPTA, and PSA were corrected in both groups (P < 0.001). There were no differences in the postoperative knee survival time from OWHTO to knee arthroplasty between the groups or postoperative complications (P = 0.53; P = 0.61).

Conclusions

Laser correction technology can effectively reduce radiation exposure, the operative time, and the rate of outliers (trial identification number (retrospectively registered): ChiCTR2200060480; date of register: 03/06/2022).

CAS and PSI increase coronal alignment accuracy and reduce outliers when compared to traditional technique of medial open wedge high tibial osteotomy: a meta-analysis

PURPOSE

Medial open-wedge high tibial osteotomy (MOWHTO) is an accepted option in the treatment of medial compartment osteoarthritis of the knee in young and active patients. Functional results are closely correlated to the correction of the mechanical axis of the lower limb. Although several angular and geometrical methods and values have been proposed in the past, the ideal target is still debated. In addition, it is important to have a deep correlation between the planned correction and the achieved correction after surgery. The aim of the present systematic review was to identify the ideal coronal correction after MOWHTO and the most accurate method to achieve it.

METHODS

A systematic review of the literature was completed on July 3rd 2020 in the Pubmed, Medline, Cochrane Reviews, and Google Scholar databases using the Medical Subject Headings (MeSH) terms: "high tibial osteotomy" AND "accuracy" OR "planning".

RESULTS

28 studies were included; 18 were focused on computer-assisted surgery (CAS) and 10 on patient-specific instrumentation (PSI). There were 598 patients in the CAS group and 501 in the control group; the rate of outliers was 16% and 38.2% respectively (P = 0.04), while there was no significant difference between the two groups (SMD = - 0.10; 95% CI 1.31 to 1.12; P = n.s.) in terms of coronal accuracy. Likewise, there were 318 patients in the PSI group and 40 in the control group; the rate of outliers was 15% and 40% respectively (P = 0.98), while there was no significant difference between the two groups (SMD = 0.01; 95% CI 0.58 to 0.59; P = 0.98).

CONCLUSIONS

A statistically significant reduced outlier rate and a non-significant increased accuracy emerged with the use of CAS when compared to the traditional surgical technique, whereas the results of PSI were still inconclusive. In addition, it emerged clearly that no consensus still exists on the ideal correction target to be achieved after surgery.

LEVEL OF EVIDENCE

III.

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.

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.

Is patient-specific instrumentation more precise than conventional techniques and navigation in achieving planned correction in high tibial osteotomy?

INTRODUCTION

Preoperative planning in high tibial osteotomy (HTO) is a critical step for achieving the desired correction and a clinically satisfactory outcome. Conventional radiography, navigation assistance and patient-specific instrumentation (PSI) are the 3 means of planning, but no prospective studies have compared precision between the 3. The aims of the present study were: (1) to analyze and compare correction precision between the 3 planning approaches at 1 year's follow-up; (2) to compare results to those reported in the literature; and (3) to analyze factors influencing the achievement of planned correction.

HYPOTHESIS

The study hypothesis was that PSI provides more precise and reproducible planned correction than conventional methods or navigation.

MATERIAL AND METHOD

Between June 2017 and June 2018, a multicenter non-randomized prospective observational study was conducted in 11 centers. One hundred and twenty-six patients with Ahlbäck grade I, II or III idiopathic medial tibiofemoral osteoarthritis with stable knee were included and allocated to 3 preoperative planning groups: conventional (group 1), navigation (group 2) and PSI (group 3). Mean age at surgery was 51.2 years (range, 19-69 years; median, 53.2 years); 100 male, 26 female. Complete weight-bearing radiographic work-up was performed preoperatively and at 1 year's follow-up. The PSI group also underwent CT as part of guide production. Target angular correction and mechanical Hip-Knee-Ankle (HKA) axis were set preoperatively. The main endpoint was the difference between planned HKA and HKA at a minimum 12 months.

RESULTS

Mean HKA difference was 1.1±3 in group 1, 2.1±2.6 in group 2 and 0.3±3.1 in group 3. Precision was better with PSI, but not significantly when comparing all 3 groups together. On pairwise intergroup comparison, there was a significant difference only between groups 2 and 3, in favor of PSI (P=0.011).

DISCUSSION

None of the 3 techniques demonstrated superiority in achieving target correction at 1 year. The study hypothesis was thus not confirmed. All 3 techniques proved reliable and precise in HTO planning.

LEVEL OF EVIDENCE

III, prospective non-randomized comparative study.

Clinical efficacy of preoperative 3D planning for reducing surgical errors during open-wedge high tibial osteotomy

Increases in posterior tibial slope (PTS) with open-wedge high tibial osteotomy (OWHTO) are often related to two surgical errors: Symmetric opening of the osteotomy gap and a tendency to open the gap from the anteromedial direction. The study objective was to define trends in these two errors using computer simulation and clinical effects of their countermeasures. First, 60 knees with varus deformity were assessed with three-dimensional (3D) planning using computed tomography to allow for the mechanical axis to pass through a point at 62.5% of the width of the tibial plateau, defined as the weight-bearing line percentage (WBL%). Anterior and posterior widths of the opening gap to maintain PTS were measured. The effect on PTS when osteotomy gaps were opened from the anteromedial direction up to 30° was evaluated. Mean anterior width (y) was 6.6 mm (range, 2.2-10.9) and mean posterior width (x) was 9.1 mm (range, 3.9-15.7), which can be expressed as y = 0.75x - 0.24. Opening gaps from the anteromedial direction at 10°, 20°, and 30° led to a mean PTS increase of 1.9°, 3.9°, and 5.6°, respectively. In most cases, WBL% with anteromedial opening at 30° passed through a point at less than 60%. In 47 knees that underwent OWHTO using 3D planning, postoperative coronal and sagittal bone corrections were mostly accurate. However, postoperative WBL% was negatively correlated with correction angle because of difficulties in predicting medial joint tightness. Preoperative 3D planning for OWHTO can reduce surgical errors, but postoperative WBL% remains variable. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Comparison of navigated and conventional high tibial osteotomy for the treatment of osteoarthritic knees with varus deformity: A meta-analysis

BACKGROUND

High tibial osteotomy (HTO) is a usefully surgical procedure to correct the malalignment and delay the progression of osteoarthritis. It is still controversy whether navigation system can offer more accuracy of targeted alignment and achieve better clinical outcomes than conventional method. The purpose of present meta-analysis was to investigate whether navigation system was superior to conventional method with regard to clinical and radiographic outcomes.

METHOD

The included studies compared the clinical and radiographic outcomes between navigated HTO group and conventional group. The clinical assessments were Lysholm Score, AKS Function Score and Arc of motion, and the radiographic outcomes were Mechanical axis (MA), Weight bearing line ratio (WBL), Outliers of alignment and Change in TPS used to evaluate alignment correction. The meta-analysis was performed using Review Manager 5.3 software. Downs and Black and the Newcastle-Ottawa Scale (NOS) were used to evaluate the study quality.

RESULT

Sixteen studies were eligible in present meta-analysis, including thirteen studies concerning opening wedge HTO and three studies involving closing wedge HTO. Clinical outcomes were only reported in studies which used opening wedge HTO. No significant differences were observed in all clinical outcomes between navigated and conventional HTO. Regarding radiographic outcomes, no significant difference in WBL ratio was observed between navigated and conventional HTO. Patients undergoing navigated HTO were associated with significantly greater in MA and lower in Outliers of alignment compared with those undergoing conventional HTO. Compared with conventional HTO, increase in TPS was significantly lower in navigated HTO group using opening wedge HTO, but decrease in TPS was significantly greater in navigated HTO group using closing wedge HTO.

CONCLUSION

Our meta-analysis demonstrated that navigated HTO offered more accuracy and precision of alignment correction, except WBL ratio. However, better clinical outcomes were not observed in navigation group.

Factors affecting articular cartilage repair after open-wedge high tibial osteotomy

BACKGROUND

To evaluate the factors that affect articular cartilage repair after open-wedge high tibial osteotomy (OWHTO) and the relationship between regeneration of articular cartilage repair and clinical outcomes.

METHODS

Among the cases of OWHTO that were performed from March 2005 to February 2012, the patients who followed up for >2years and received a second-look arthroscopy were retrospectively reviewed. For clinical evaluation, the Knee Society scores and Western Ontario and McMaster Universities Osteoarthritis Index score were measured. For radiologic evaluation, the Kellgren-Lawrence scale, mechanical femorotibial angle, and joint line obliquity were used. In the initial and second-look arthroscopy, the status of the articular cartilage of the medial compartment was evaluated.

RESULTS

A total of 62 knees (61 patients) were included in this study. Articular cartilage repair was observed in 18 knees (29.0%). In multiple logistic regression analysis, patients with Kellgren-Lawrence Grade 4 (OR 0.076; 95% CI 0.007-0.822; P=0.034), the existence of a bipolar lesion (OR 0.108; 95% CI 0.016-0.724; P=0.022), or joint line obliquity >5° (OR 0.109; 95% CI 0.013-0.936; P=0.043) had significantly lower odds of articular cartilage repair compared to the corresponding counter group. In a comparison of clinical outcomes between a group that had articular cartilage repair and a group without repair, no significant difference was observed (P>0.05).

CONCLUSIONS

Severe arthrosis, existence of a bipolar lesion, and marked postoperative joint line obliquity had a negative impact on articular cartilage repair after OWHTO. However, articular cartilage repair showed unknown clinical significance.

Intraoperative adjustment of alignment under valgus stress reduces outliers in patients undergoing medial opening-wedge high tibial osteotomy

INTRODUCTION

A considerable percentage of outliers with under- or over-correction continue to be reported despite precise preoperative planning and cautious intraoperative correction of lower limb alignment in medial opening-wedge high tibial osteotomy (MOWHTO). The purpose of this study was to determine whether our novel technique for the intraoperative adjustment of alignment under valgus stress reduces the number of outliers in patients undergoing MOWHTO compared to the conventional technique, which corrects alignment according to the cable method only.

MATERIALS AND METHODS

One hundred seventeen consecutive knees were enrolled in this case-control study. The first 52 knees (51 patients) were corrected in accordance with preoperative plans using the Dugdale method with modification with an intraoperative cable (group 1). In the other 65 knees (60 patients), the angle was corrected using the Dugdale method and limb alignment was adjusted using the intraoperative cable technique by applying valgus stress to the knee joint (group 2). The postoperative weight bearing line ratios and mechanical axis of the lower limb were compared at postoperative one year. Each knee was evaluated according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score preoperatively and at postoperative one year.

RESULTS

A significant reduction in the number of outliers was seen in group 2 compared to group 1 (group 1 = 48.1%, group 2 = 9.2%, p < 0.001). Nineteen of 52 knees (36.5%) were under-corrected in group 1, whereas 6 of 65 knees (9.2%) were under-corrected in group 2 (p < 0.001). Six of 52 knees (11.6%) were over-corrected in group 1, whereas 0 of 65 knees (0.0%) were over-corrected in group 2 (p = 0.005). At one -year after operation, group 2 showed significantly lower WOMAC score than group 1 (p = 0.014).

CONCLUSIONS

Intraoperative adjustment of alignment under valgus stress significantly reduced the number of outliers compared to a technique that corrected alignment using the cable method in patients undergoing MOWHTO.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Computer-Assisted Navigation in High Tibial Osteotomy

Computer-assisted navigation is used to improve the accuracy and precision of correction angles during high tibial osteotomy. Most studies have reported that this technique reduces the outliers of coronal alignment and unintended changes in the tibial posterior slope angle. However, more sophisticated studies are necessary to determine whether the technique will improve the clinical results and long-term survival rates. Knowledge of the navigation technology, surgical techniques and potential pitfalls, the clinical results of previous studies, and understanding of the advantages and limitations of the computer-assisted navigation are crucial to successful application of this new technique in high tibial osteotomy. Herein, we review the evidence concerning this technique from previous studies.

Outcome reporting following navigated high tibial osteotomy of the knee: a systematic review

PURPOSE

This systematic review evaluates radiographic and clinical outcome reporting following navigated high tibial osteotomy (HTO). Conventional HTO was used as a control to compare outcomes and furthermore investigate the quality of evidence in studies reporting outcomes for navigated HTO. It was hypothesized that navigated HTO will show superior clinical and radiographic outcomes compared to conventional HTO.

METHODS

Two independent reviewers searched PubMed, Ovid (MEDLINE), EMBASE, and Cochrane databases for studies reporting outcomes following navigated HTO. Titles, abstracts, and full-text were screened in duplicate using an a priori inclusion and exclusion criteria. Descriptive statistics were calculated using Minitab ^® statistical software. Methodological Index for Nonrandomized Studies (MINORS) and Cochrane Risk of Bias Scores were used to evaluate methodological quality.

RESULTS

Thirty-four studies which involved 2216 HTOs were analysed in this review, 1608 (72.6 %) navigated HTOs and 608 (27.4 %) conventional HTOs. The majority of studies were of level IV evidence (16). Clinical outcomes were reported in knee and function scores or range of motion comparisons. Postoperative clinical and functional scores were improved by navigated HTO although it is not demonstrated if there is significant improvement compared to conventional HTO. Most common clinical outcome score reported was Lysholm scores (6) which report postoperative scores of 87.8 (standard deviation 5.9) and 88.8 (standard deviation 5.9) for conventional and navigation-assisted HTO, respectively. Radiographic outcomes reported commonly were weight-bearing mechanical axis, coronal plane angle, and posterior tibial slope angle in the sagittal plane. Studies have shown HTO gives significant correction of mechanical alignment and navigated HTO produces significantly less change in posterior tibial slope postoperatively compared to conventional. The mean MINORS for the 17 non-comparative studies was 9/16, and 15/24 for the 14 non-randomized comparative studies.

CONCLUSION

Navigation HTO results in improved mechanical axis alignment and demonstrates significantly better control over the tibial slope angle change postoperatively compared to conventional methods; however, these improvements have not yet been reflected in clinical outcome scores. Overall the studies report HTO does create significantly improved knee scores and functions compared to patients' preoperative ratings regardless of technique. Future studies on HTO outcomes need to focus on consistency of outcome reporting.

LEVEL OF EVIDENCE

IV.