Trends in High Tibial Osteotomy and Knee Arthroplasty Utilizations and Demographics in Korea From 2009 to 2013

Annual Trends of High Tibial Osteotomy: Analysis of an Official Registry in Italy

Background and Objectives: Knee osteoarthritis is a serious burden for modern countries. Timing of surgery and treatment choice are still a matter of controversy in the orthopedic literature. The purpose of this study was to ascertain the incidence and hospitalization trends of high tibial osteotomy in Italy from 2001 to 2016. Materials and Methods: Data are sourced from the National Hospital Discharge Reports (SDO) of the Italian Ministry of Health between 2001 and 2016. Results: A total of 34,402 high tibial osteotomies were performed over the study period in Italy. The cumulative incidence was 3.6 cases per 100,000 residents. The age classes 50-54, 55-59 showed the higher number of procedures. In pediatric patients (0-19 years), high tibial osteotomies are also largely performed. The majority of patients having surgery were men with a M/F ratio of 1.5. The mean age of patients was 44.2 ± 19.2 years. Males were significantly younger than females (43.3 ± 20.7 vs. 45.6 ± 17.7). The average length of hospitalization was 6.1 ± 7.3 days. Over the course of the analysis, a declining trend in hospital stay length was seen. The main primary diagnosis codes were "Varus knee" (736.42 ICD-9-CM code, 33.9%), "Osteoarthrosis, localized, primary, leg region" (715.16 ICD-9-CM code, 9.5%). Conclusions: Over the study period, high tibial osteotomies in Italy almost halved. Varus deformity and knee osteoarthritis are the leading causes requiring high tibial osteotomy. Except for the pediatric setting, results showed that from the 20-24 age class to the 50-54 age class, there was an increasing request for knee osteotomy, whereas in those aged >60 years, the incidence progressively decreased. The evident decline in HTO performed over the years in Italy seems to reflect a minor role for knee osteotomy in the management of knee OA, as it seems to be primarily reserved for younger male patients.

Trends and outcomes in the surgical management of young adults with knee osteoarthritis using high tibial osteotomy and unicompartmental knee arthroplasty

INTRODUCTION

A significant portion of knee osteoarthritis is diagnosed in patients under the age of 55, where greater activity demands make total knee arthroplasty less desirable. High tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) are useful alternatives, but there is little understanding of which procedure is advantageous. Hence, this study examines the utilization, complication, and reoperation rates among the HTO vs. UKA in young patients with primary osteoarthritis.

METHODS

A retrospective review of the National Surgical Quality Improvement Program was performed to identify 2318 patients < 55 years of age who received either a HTO or UKA for primary osteoarthritis between 2011 and 2021. Bivariate analyses compared preoperative and intraoperative characteristics among each procedure. Then, multivariate analyses examined if either procedure was associated with worse 30-day postoperative complications or need for reoperation, independent of the statistically significant pre- and intraoperative disparities.

RESULTS

UKAs were performed 14.2 times more commonly than HTOs, and the patients selected for HTO were more likely to be younger, have a lower BMI, have the healthiest ASA Class score, and less likely to have hypertension requiring medication (p < 0.001). HTOs took 17.5% longer to perform and had a longer average length of stay (p < 0.001), while UKAs were more likely to be performed out-patient (p < 0.001). HTOs also had higher rates of serious complications (p = 0.02), overall complications (p = 0.004), and need for reoperation (p = 0.004). Multivariate modelling demonstrated that procedure type was not a predictor of serious complications, but the use of HTO was significantly associated with any complications (odds ratio = 3.63, p = 0.001) and need for reoperation (3.21, p = 0.029).

CONCLUSION

Although healthier patients were selected for HTOs, UKAs were found to have a lower risk of complications and immediate reoperation. Additionally, UKAs had the advantage of lower operative burden, shorter length of stay, and a higher efficacy in outpatient settings.

Factors to improve odds of success following medial opening-wedge high tibial osteotomy: a machine learning analysis

BACKGROUND

Although high tibial osteotomy (HTO) is an established treatment option for medial compartment osteoarthritis, predictive factors for HTO treatment success remain unclear. This study aimed to identify informative variables associated with HTO treatment success and to develop and internally validate machine learning algorithms to predict which patients will achieve HTO treatment success for medial compartmental osteoarthritis.

METHODS

This study retrospectively reviewed patients who underwent medial opening-wedge HTO (MOWHTO) at our center between March 2010 and December 2015. The primary outcomes were a lack of conversion to total knee arthroplasty (TKA) and achievement of a minimal clinically important difference of improvement in the Knee Injury and Osteoarthritis Outcome Score (KOOS) at a minimum of five years postoperatively. Recursive feature selection was used to identify the combination of variables from an initial pool of 25 features that optimized model performance. Five machine learning algorithms (XGBoost, multilayer perception, support vector machine, elastic-net penalized logistic regression, and random forest) were trained using five-fold cross-validation three times and applied to an independent test set of patients. The performance of the model was evaluated by the area under the receiver operating characteristic curve (AUC).

RESULTS

A total of 231 patients were included, and 200 patients (86.6%) achieved treatment success at the mean of 9 years of follow-up. A combination of seven variables optimized algorithm performance, and the following specific cutoffs increased the likelihood of MOWHTO treatment success: body mass index (BMI) ≤ 26.8 kg/m2, preoperative KOOS for pain ≤ 46.0, preoperative KOOS for quality of life ≤ 33.0, preoperative International Knee Documentation Committee score ≤ 42.0, preoperative Short-Form 36 questionnaire (SF-36) score > 42.25, three-month postoperative hip-knee-ankle angle > 1.0°, and three-month postoperative medial proximal tibial angle (MPTA) > 91.5° and ≤ 94.7°. The random forest model demonstrated the best performance (F1 score: 0.93; AUC: 0.81) and was transformed into an online application as an educational tool to demonstrate the capabilities of machine learning.

CONCLUSIONS

The random forest machine learning algorithm best predicted MOWHTO treatment success. Patients with a lower BMI, poor clinical status, slight valgus overcorrection, and postoperative MPTA < 94.7 more frequently achieved a greater likelihood of treatment success.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Particulated Costal Hyaline Cartilage Allograft With Subchondral Drilling Improves Joint Space Width and Second-Look Macroscopic Articular Cartilage Scores Compared With Subchondral Drilling Alone in Medial Open-Wedge High Tibial Osteotomy

PURPOSE

To compare the articular cartilage regeneration based on second-look arthroscopy in patients who underwent medial open-wedge high tibial osteotomy (MOWHTO) combined with particulated costal hyaline cartilage allograft (PCHCA) implantation with those who underwent MOWHTO and subchondral drilling (SD). Moreover, we compared the clinical and radiographic outcomes between the groups.

METHODS

From January 2014 to November 2020, patients with full-thickness cartilage defect on the medial femoral condyle who underwent MOWHTO combined with PCHCA (group A) or SD (group B) were reviewed. Fifty-one knees were matched after propensity score matching. The status of regenerated cartilage was classified according to the International Cartilage Repair Society-Cartilage Repair Assessment (ICRS-CRA) grading system and Koshino staging system, based on second-look arthroscopic findings. Clinically, the Knee Injury and Osteoarthritis Outcome Score, the Western Ontario and McMaster Universities Osteoarthritis Index, and range of motion were compared. Radiographically, we compared the differences in the minimum joint space width (JSW) and change in JSW.

RESULTS

The average age was 55.5 years (range, 42-64 years), and the average follow-up period was 27.1 months (range, 24-48 months). Group A showed a significantly better cartilage status than group B based on the ICRS-CRA grading system and Koshino staging system (P < .001 and <.001, respectively). There were no significant differences in clinical and radiographic outcomes between groups. In group A, the minimum JSW at the last follow-up was significantly increased than that before surgery (P = .013), and a significantly greater increase in JSW was observed in group A (P = .025).

CONCLUSIONS

When performed with MOWHTO, the combination of SD and PCHCA was associated with superior articular cartilage regeneration on the ICRS-CRA grading and Koshino staging on second-look arthroscopy performed at a minimum of 2 years follow-up than SD alone. However, there was no difference in clinical outcomes.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Iliac vein compression syndrome by lumbar degenerative changes is associated with deep vein thrombosis after total knee arthroplasty

INTRODUCTION

This study aimed to identify whether iliac vein compression syndrome(IVCS) is associated with deep vein thrombosis(DVT) after total knee arthroplasty(TKA) and whether lower lumbar degenerative changes were risk factors for IVCS.

MATERIALS AND METHODS

A total of 259 consecutive patients who underwent TKA from January 2019 to March 2022 was retrospectively reviewed. Preoperative plain radiographs of lumbar spines and CT venography (CTV) for DVT diagnosis at postoperative 7 days were performed in all patients. Imaging findings of lower lumbar degenerative changes were analyzed on plain radiograph including lateral osteophytes, scoliosis, lateralolisthesis, retrolisthesis, anterolisthesis, and lower lumbar lordosis angle (LLLA). Percent compression at the left common iliac vein (LCIV) and right common iliac vein (RCIV) as well as DVT were evaluated on CTV. Moreover, IVCS was defined as greater than 50% of compression of the iliac vein on CTV.

RESULTS

DVT occurred in 79 patients (30.5%) after TKA. The overall occurrence of DVT was significantly higher in patients with IVCS of LCIV (52.8%) than those without (18.8%, P < 0.001). When DVT was further subdivided, compared to non-IVCS, IVCS of LCIV was significantly associated with bilateral DVT (P < 0.001, both), especially distal DVT (P < 0.001, both), and IVCS of RCIV was significantly associated with right-side DVT (P = 0.031), especially popliteal (P = 0.008) and distal DVT(P = 0.011). Female patients (OR: 3.945, P = 0.039), presence of left osteophyte (OR: 2.348, P = 0.006), and higher LLLA (OR: 1.082, P < 0.001) were significantly associated with IVCS of LCIV, and presence of right osteophyte (OR: 3.494, P = 0.017) was significantly associated with IVCS of RCIV.

CONCLUSION

IVCS was significantly associated with DVT after TKA and lumbar degenerative changes with lateral osteophytes and hyperlordosis were significant risk factors for IVCS.

A Comprehensive Research on the Prevalence and Evolution Trend of Orthopedic Surgeries in Romania

Accurate knowledge of the prevalence and trends of orthopedic surgeries can facilitate the design of medical plans for effective treatments. The National Endoprosthetic Registry (NER) in Romania provides statistics on endoprosthetic activity (hip, knee), cases of fractures and bone tumors as a result of the legal obligations to report interventions performed by all orthopedic traumatology hospitals/wards in the country. The aim of this study is to describe the annual volumes of orthopedic surgeries between 2001 and 2022 in Romania and analyze the current and future evolution trends of the studied surgeries, gender differences and regional differences based on a complete survey carried out at a national level. For the period 2001-2022, we extracted from the NER the annual volumes of orthopedic interventions performed. With these data, we studied the prevalence and estimated, with the support of an original calculation methodology, the variation trends of orthopedic surgeries in two situations: over the entire 21-year period, respectively, and over the period 2001-2020, which does not include the pandemic period. For hip replacement surgery and knee replacement surgery, we showed the prevalence by subcategory of interventions, gender distribution, regional prevalence and regional density calculated by the annual averages of the total number of cases reported per 100,000 people in the 40 counties of the country and the capital, Bucharest. We also determined the variations in hip and knee arthroplasty revision burdens, calculated as a percentage between the number of revisions and the number of primary interventions in the same period. We determined the regional densities of revision burdens. The total number of orthopedic surgeries in the period 2001-2022 was 1,557,247, of which 189,881 were hip replacement surgeries; 51,035 were knee replacement surgeries; 11,085 were revision hip arthroplasty; 1497 were revision knee arthroplasty; 541,440 were operated fractures; and 16,418 were operated bone tumors. The growth rates of surgical interventions are hip replacement surgery, +8.19%; knee replacement surgery, +19.55%; revision hip arthroplasty, +9.43%; and revision knee arthroplasty, +28.57%. With these data, we have estimated a doubling of the volume of primary and revision interventions of the hip until 2034 and the knee until 2027, respectively. Operated bone tumors register an annual decrease of -4.52% thanks to modern treatments. There are clear gender differences; for primary hip interventions, the proportion of women is 58.82%, and for knee interventions, the proportion of women is 76.42%. This is the first research that, with the support of exhaustive data from the NER, analyzes for the period 2001-2022 the annual number of orthopedic surgeries in Romania. It allows knowledge of the large, anticipated increases in orthopedic surgery and provides a quantitative basis for future policy decisions related to the need for medical personnel and material resources.

Effect of Prior Knee Arthroscopy on Midterm Outcomes After Medial Opening-Wedge High Tibial Osteotomy: A Propensity Score-Matched Analysis

Background

Knee arthroscopy is frequently performed to improve joint function and relieve pain. However, there is no consensus regarding the effect of prior arthroscopy on outcomes following medial opening-wedge high tibial osteotomy (MOWHTO).

Purpose

To compare midterm clinical outcomes and survival rates after MOWHTO between patients with and without a history of knee arthroscopy.

Study Design

Cohort study; Level of evidence, 3.

Methods

We enrolled patients who underwent MOWHTO between March 2008 and February 2017 and had ≥4 years of follow-up. Patients who had undergone knee arthroscopy were included in an arthroscopy group, and those who had not were included as controls. After propensity score matching based on age, sex, body mass index, and lesion size, 80 patients in each group were included. Clinical outcomes were assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS), 36-Item Short Form Health Survey, and Tegner Activity Scale. Furthermore, survival rates and relevant risk factors that affected joint survivorship were analyzed, wherein conversion to total knee arthroplasty was considered the endpoint.

Results

Although the pre- to postoperative improvement in clinical outcomes did not differ significantly between the groups, there were significant between-group differences in final postoperative scores on the KOOS-Activities of Daily Living (arthroscopy vs control, 78.1 ± 10.6 vs 81.0 ± 9.8; P = .031), KOOS-Sport and Recreation (45.4 ± 12.8 vs 48.7 ± 13.5; P = .045), 36-Item Short Form Health Survey Physical Component Summary (65.1 ± 12.7 vs 69.3 ± 11.8; P = .017), and Tegner Activity Scale (4.1 ± 1.1 vs 4.5 ± 1.0; P = .007). The survival rate was 96.8% at a mean follow-up of 8 years, and survival was not associated with a history of arthroscopy (P = .697; log-rank test).

Conclusion

Although patients with prior arthroscopy had some inferior patient-reported outcome scores after MOWHTO, the overall clinical improvements were similar in the arthroscopy and control groups.

Incidence and Trends of High Tibial Osteotomy and Unicompartmental Knee Arthroplasty Over the Past Decade: A Lost Art

Background

After failed nonoperative treatment, unicompartmental osteoarthritis can be treated surgically by either unicompartmental knee arthroplasty (UKA) or high tibial osteotomy (HTO). The purpose of this retrospective study is to analyze utilization and demographic trends of UKA and HTO relative to total knee arthroplasty (TKA) over the past decade.

Methods

A retrospective review was conducted using the PearlDiver database. Patients that received a UKA or HTO were identified. Trend analyses of surgical procedure utilization were performed with the Mann-Kendall trend test. Demographic data and the rates of various comorbidities were also queried.

Results

A total of 103,465 UKAs, 2183 HTOs, and 1,413,425 TKAs, between 2010 and 2021 quarter 1, were analyzed. Trend analyses revealed that relative to TKA utilization, UKA utilization significantly increased (P < .001) while HTO utilization significantly decreased (P < .001). The compound annual growth rate of UKA utilization relative to TKA was +5.16% from 2010 to 2017 but was -10.61% from 2018 to 2021, while that of HTO relative to TKA was -9.69% from 2010 to 2021. Demographic analyses demonstrated the UKA cohort (63.1) was significantly older than the HTO cohort (46.5) (P < .001). Additionally, there were significantly more female patients who underwent UKA than HTO (P < .001).

Conclusions

The present study demonstrated that relative to TKA, UKA utilization increased from 2010 to 2017, with a subsequent decrease afterward, whereas HTO utilization decreased since 2010. Demographic differences exist between the 2 operations, with HTOs more commonly performed in younger male patients, and UKAs in older female patients.

Level of Evidence

Level III.

Comparing Unicompartmental Knee Arthroplasty and High Tibial Osteotomy for Isolated Medial Compartment Knee Osteoarthritis

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Both unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) allow for compartment-specific intervention on an arthritic knee joint that preserves bone stock and native soft tissue compared to a total knee arthroplasty (TKA). Both operations give a more natural feeling with native proprioception compared with a TKA.

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HTO is better suited in patients who are younger (<55 years-of-age), have a body mass index (BMI) <30 kg/m2, high activity requirements, mechanical malalignment, asymmetric varus, isolated anterior cruciate ligament insufficiency, need for multiplanar correction, and a preference for joint preserving interventions. Recent data suggest that age (>55 years-of-age) should not solely contraindicate a HTO.

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UKA may be chosen in patients who are older (>55 years-of-age), low activity requirements, have a BMI <40 kg/m2, severe osteoarthritis with significant joint space narrowing, acceptable coronal alignment, symmetric varus, and patient preference for arthroplasty.

Effect of total knee replacement on skeletal muscle mass measurements using dual energy X-ray absorptiometry

Sarcopenia is becoming prevalent in an increasing number of older adults undergoing total knee replacement (TKR) surgery. Metal implants may overestimate lean mass (LM) measured using dual-energy X-ray absorptiometry (DXA). This study aimed to examine the effects of TKR on LM measurements according to automatic metal detection (AMD) processing. The participants from Korean Frailty and Aging Cohort Study, who had underwent TKR were enrolled. A total of 24 older adults (mean age 76.4 ± 4.0 years, 92% female) were included in the analysis. The SMI with AMD processing was 6.1 ± 0.6 kg/m², which was lower than that without AMD processing of 6.5 ± 0.6 kg/m² (p < 0.001). The LM of the right leg with AMD processing was lower than that without AMD in 20 participants who had underwent TKR surgery on the right (5.5 ± 0.2 kg vs. 6.0 ± 0.2 kg, p < 0.001), and that of the left leg was also lower in with AMD processing than in without AMD processing in 18 participants who had underwent TKR surgery on the left (5.7 ± 0.2 kg vs. 5.2 ± 0.2 kg, p < 0.001). Only one participant was classified as having low muscle mass without AMD processing, but this came to four after AMD processing. LM assessment in individuals who had TKR could be significantly different according to the use of AMD.

Cartilage Regeneration Using Human Umbilical Cord Blood Derived Mesenchymal Stem Cells: A Systematic Review and Meta-Analysis

Background and Objectives: Human umbilical-cord-blood-derived mesenchymal stem cells (hUCB-MSCs) have recently been used in clinical cartilage regeneration procedures with the expectation of improved regeneration capacity. However, the number of studies using hUCB-MSCs is still insufficient, and long-term follow-up results after use are insufficient, indicating the need for additional data and research. We have attempted to prove the efficacy and safety of hUCB-MSC treatment in a comprehensive analysis by including all subjects with knee articular cartilage defect or osteoarthritis who have undergone cartilage repair surgery using hUCB-MSCs. We conducted a meta-analysis and demonstrated efficacy and safety based on a systematic review. Materials and Methods: This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. For this study, we searched the PubMed, Embase, Web of Science, Scopus, and Cochrane Library literature databases up to June 2022. A total of seven studies were included, and quality assessment was performed for each included study using the Newcastle−Ottawa Quality Assessment Scale. Statistical analysis was performed on the extracted pooled clinical outcome data, and subgroup analyses were completed. Results: A total of 570 patients were included in the analysis. In pooled analysis, the final follow-up International Knee Documentation Committee (IKDC) score showed a significant increase (mean difference (MD), −32.82; 95% confidence interval (CI), −38.32 to −27.32; p < 0.00001) with significant heterogeneity (I2 = 93%, p < 0.00001) compared to the preoperative score. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores at final follow-up were significantly decreased (MD, 30.73; 95% CI, 24.10−37.36; p < 0.00001) compared to the preoperative scores, with significant heterogeneity (I2 = 95%, p < 0.00001). The visual analog scale (VAS) score at final follow-up was significantly decreased (MD, 4.81; 95% CI, 3.17−6.46; p < 0.00001) compared to the preoperative score, with significant heterogeneity (I2 = 98%, p < 0.00001). Two studies evaluated the modified Magnetic Resonance Observation of Cartilage Repair Tissue (M-MOCART) score and confirmed sufficient improvement. In a study analyzing a group treated with bone marrow aspiration concentrate (BMAC), there was no significant difference in clinical outcome or M-MOCART score, and the post-treatment International Cartilage Repair Society (ICRS) grade increased. Conclusion: This analysis demonstrated the safety, efficacy, and quality of repaired cartilage following hUCB-MSC therapy. However, there was no clear difference in the comparison with BMAC. In the future, comparative studies with other stem cell therapies or cartilage repair procedures should be published to support the superior effect of hUCB-MSC therapy to improve treatment of cartilage defect or osteoarthritis.

Vancomycin-soaked femoral head allograft in opening wedge high tibia osteotomy enables earlier postoperative recovery and reduces infection rates compared to allogenic bone chips

PURPOSE

To investigate the benefits of vancomycin-soaked femoral head allograft versus allogenic bone chips as an osteotomy gap filler in reducing infection rates and perioperative pain control after medial opening wedge high tibial osteotomy (MOW-HTO).

METHODS

Retrospective analysis of 114 knees that underwent MOW-HTO between 2013 and 2020. Osteotomy gaps were filled with vancomycin-soaked femoral head allograft (Study Group) or allogenic bone chips (Control Group). Both groups received systemic antibiotics. Perioperative parameters studied included pain, blood loss, length of stay, postoperative day (POD1) pain scores at rest, with activity as well as ambulatory distance. Patients in the Study Group were also followed up prospectively and clinical outcome scores, namely Knee Society Score, Oxford knee score (OKS) and Physical and Mental Component of the Short-Form 36 Questionnaire (PCS and MCS, respectively). Statistical analyses using Student's T-test were performed between the groups.

RESULTS

Patients of the study group had significantly better POD1 visual analogue scale (VAS) at rest (0.9 ± 1.6 vs 2.9 ± 1.2, p < 0.001) as well as when active (3.0 ± 1.9 vs 5.8 ± 1.5, p < 0.001). A greater proportion of patients in the study group ambulated on POD 1, (90.6% vs 26.0%, p < 0.001). Of those who ambulated on POD1, study group patients managed to cover a greater ambulatory distance (13.9 ± 7.4 m vs 8.4 ± 9.3 m, p < 0.05). The proportion of study group patients requiring patient-controlled analgesia (PCA) was also significantly less compared to the control group (32.8% vs 58.0%, p < 0.05). Of those requiring PCA, the amount of morphine requirement was also significantly reduced in the group with vancomycin-soaked allograft (8.7 ± 8.1 mg vs 23.9 ± 33.0 mg, p < 0.05). The study group also had a reduced length of stay (3.5 ± 2.0 days vs 5.5 ± 2.6 days, p < 0.001). Patients in the study group demonstrated significant improvement in Knee Society Knee Score (KSKS), OKS, PCS and MCS at 12 months postoperatively. The study group had a significantly reduced incidence of superficial wound infections compared to the control group (3.1% vs 18.0%, p < 0.05).

CONCLUSION

Vancomycin-soaked femoral head allograft reduced superficial and deep wound infections in MOW-HTO. It was also effective in reducing postoperative pain, thereby enabling early ambulation and shorter hospital stays.

LEVEL OF EVIDENCE

Retrospective comparative study, III.

Does the degree of intraoperatively identified cartilage loss affect the outcomes of primary total knee arthroplasty without patella resurfacing? A prospective comparative cohort study

Purpose

The aim of this study was to investigate whether the degree of patellar cartilage loss confirmed during index surgery affects the clinical and radiologic outcomes of total knee arthroplasty (TKA) performed without patellar resurfacing.

Methods

We prospectively divided 2012 patients with a minimum follow-up of 12 months into two groups according to intraoperatively graded cartilage lesions graded using the International Cartilage Repair Society (ICRS) system: group 1, grades 0‒2 (n = 110); group 2, grades 3‒4 (n = 102). Relevant locations, such as medial, lateral, or both facets of the patella, were also assessed. Clinical outcomes were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index, Feller’s patella score, and Kujala anterior knee pain score. Radiographic outcomes included patellar tilt angle and lateral patellar shift on Merchant’s view.

Results

Clinical and radiographic outcomes were not significantly different between the two groups. No patient underwent secondary patellar resurfacing. Although the lateral facet was significantly more involved, there were no significant differences in outcomes.

Conclusions

The degree of intraoperatively identified patellar cartilage loss did not affect the short-term outcomes following primary TKA without patellar resurfacing.

Level of evidence II: Prospective comparative study.

Mid- to Long-Term Outcomes After Medial Open-Wedge High Tibial Osteotomy in Patients With Radiological Kissing Lesion

Background:

Although medial open-wedge high tibial osteotomy (MOWHTO) is the treatment of choice for patients with mild to moderate osteoarthritis with varus malalignment, concerns about inferior outcomes in patients with preoperative radiological kissing lesion (RKL) remain.

Purpose:

To compare the mid- to long-term clinical and radiological results and survivorship after MOWHTO in patients with versus without preoperative RKL.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Included were 122 knees in patients who underwent MOWHTO with a medial locked plate and had minimum 5-year follow-up data. The mean age at surgery was 55.9 years (range, 38-65 years), and the mean follow-up was 7.5 years (range, 5-12.8 years). All patients had undergone second-look arthroscopy around 2 years after MOWHTO. The knees were divided into an RKL group (n = 17) and no-RKL group (n = 105) based on preoperative standing radiographs. The authors compared postoperative American Knee Society (AKS) knee and function scores, range of motion, and improvements in AKS scores between groups, as well as hip-knee-ankle angle, medial proximal tibial angle, and joint-line convergence angle from preoperatively to postoperatively. Also compared were the degree of cartilage regeneration between first- and second-look arthroscopy and the survival rate after index surgery.

Results:

Preoperative AKS scores were significantly lower in the RKL group versus the no-RKL group (AKS knee, 79.6 ± 7.5 vs 83.8 ± 3.9, P = .037; AKS function, 68.8 ± 9.3 vs 76.0 ± 5.1, P = .006). Likewise, postoperative AKS scores were significantly lower in the RKL group versus the no-RKL group (AKS knee: 91.3 ± 4.2 vs 94.4 ± 1.6, respectively, P = .008; AKS function: 90.0 ± 10.0 vs 97.6 ± 4.5, respectively, P = .007). However, all patients had excellent postoperative AKS knee and function scores (>80). Moreover, there were no between-group differences in pre- to postoperative improvement in AKS scores, postoperative radiological changes, or grade of cartilage regeneration. The survival rates in the RKL and no-RKL groups were 100% and 97.1%, respectively (P ≥ .999).

Conclusion:

Although the latest clinical scores were lower in the RKL group than in the no-RKL group, comparable results in postoperative clinical improvement, cartilage regeneration, and survivorship were observed in patients with RKL at mid- to long-term follow-up.

Matched-Pair Analysis of Magnetic Resonance Images for Location of the Common Peroneal Nerve in Valgus Knees: Comparison with the Varus Knees

This study aimed to assess the distance and angular location of the common peroneal nerve (CPN) on axial magnetic resonance imaging (MRI) in the valgus knees and compare the measurements with those obtained from the control group. We compared the location of the CPN according to the type of alignment by performing a subgroup analysis. From January 2009 to December 2019, we identified 41 knees with preoperative MRI in patients who underwent total knee arthroplasty (TKA) for valgus deformity (valgus group). We performed one-to-two matched-pair analysis to a cohort of patients who underwent MRI but were not candidates for TKA (control group), according to sex and age. The valgus group was classified according to the grading system reported by Ranawat et al, and the control group was also subdivided according to the hip-knee-ankle (HKA) angle obtained from lower extremity scanography: neutral (-3 to +3 degrees from the neutral mechanical axis), valgus (> +3 degrees), and varus alignment (< -3 degrees). Distance between the CPN and posterolateral cortex of the tibia at the knee joint (distance J) and tibial cut level (distance C) were measured. Angle of the CPN from the central anteroposterior axis of the tibia (angle α) was measured. We compared the measurements between the groups. Distance J was significantly closer in the valgus group (p < 0.001), whereas angle α was significantly smaller in the valgus group (p < 0.001). However, no significant differences were found in the subgroup analysis. Moreover, a significant correlation was found between distance J and the HKA angle (p < 0.001). The location of the CPN in the valgus knees was closer to the posterolateral cortex of the tibia at the joint level and showed a smaller angle than that in the other aligned knees. We recommend that lateral soft tissue release for valgus knees should not be performed at the joint line. The results of this study suggest that this would be less safe than a release performed at the level of the proximal tibial bone resection.

New Classification for Periprosthetic Distal Femoral Fractures Based on Locked-Plate Fixation Following Total Knee Arthroplasty: A Multicenter Study

BACKGROUND

This study aimed to establish a new classification using locked-plate fixation for periprosthetic distal femoral fracture (PDFF) following total knee arthroplasty (TKA) and to determine when dual locked-plate fixation is necessary through defining this classification.

METHODS

One-hundred fifteen consecutive PDFFs that underwent operative treatment were reviewed from 2011 to 2019 with minimum 1-year follow-up. Most PDFFs were fixed with single or dual locked-plate fixations using the minimally invasive plate osteosynthesis technique. Based on preoperative radiographs, PDFFs were classified according to the level of main fracture line relative to the anterior flange of femoral component: type I and II, main fracture line located proximal and distal to the anterior flange; and type III, component instability regardless of fracture line requiring revisional TKA. Furthermore, type II fractures were subclassified based on the direction of fracture beak as follows: type II_L, lateral-beak; type II_M, medial-beak. The incidence, treatment methods, and complications were analyzed according to the classification.

RESULTS

Incidences of type I, II_L, II_M, and III were 64.4%, 8.7%, 24.3%, and 2.6%, respectively. Meanwhile, most PDFFs in type I and II were treated with lateral single locked-plate fixations, except for type II_M, which was treated with either single or dual locked-plate fixations. Overall complications were significantly higher in type II (28.9%) than in type I (10.8%, P = .019). In type II_M, bone union-related complications were significantly higher in single locked-plate fixation (50.0%) than in dual locked-plate fixation (5.6%; P = .013).

CONCLUSION

The new classification provides practical and obvious strategies for the treatment of PDFF following TKA using locked-plate fixation. For type II_M fracture, dual plate fixation is necessary to prevent fixation failure or nonunion.

The Design of the Patellar Component Does Not Affect the Patient-Reported Outcome Measures in Primary Posterior-Stabilized Total Knee Arthroplasty: A Randomized Prospective Study

This randomized comparative study was conducted to investigate the outcomes of patellar resurfacing with a medialized dome or an anatomical type in patients receiving primary unilateral posterior-stabilized TKA. Between March 2019 and January 2021, 98 knees were randomly assigned to receive patellar resurfacing by a medialized dome type (group D, 49 knees) or an anatomic type (group A, 49 knees). The primary outcome was the Knee Injury and Osteoarthritis Outcome Score. The secondary outcomes were the Western Ontario and McMaster Universities Osteoarthritis Index, Feller’s patella score, the Kujala anterior knee pain score, knee joint range of motion (ROM), and postoperative complications, including periprosthetic patellar fracture, patellar tilt angle, and lateral patellar shift. Patient-reported outcomes were not significantly different between the two groups. The ROM of the knee joint was significantly better in group A at six months after surgery (p = 0.021). No complications such as patellar fractures were observed. The anatomic type of patellar component showed a significant improvement of the patellar tilt angle after surgery compared with the medialized dome type of component. However, there were no significant differences in patient-reported clinical outcomes between the two groups during the follow-up period of 12 months.

Risk of Revision and Adverse Outcomes Following Partial Knee Replacement and High Tibial Osteotomy for Unicompartmental Knee Osteoarthritis: A Nationwide Cohort Study

PURPOSE

To investigate comparative study for potential associations of adverse outcomes as well as survival rates after high tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA).

METHODS

We reviewed the Korean National Health Insurance claims database from January 1, 2007 to May 31, 2019. A total of 90,705 patients aged 30-90 years who were newly treated for HTO or UKA were identified considering their eligibility. We performed four rounds of propensity score matching to reduce imbalance of baseline characteristics, especially disparities among different age groups. Multivariable logistic regression models were used to compare the risk of revision and various unwanted medical problems between HTO and UKA treatment groups after propensity score matching.

RESULTS

23,563 matched patients were assigned to each group on the basis of propensity score. HTO showed higher risk of revision than UKA at 5 years, 10 years and the whole observed period (hazard ratio: 1.21, 95% CI 1.10-1.34). Deep vein thromboembolism (0.27, 0.21-0.35), and surgical site infection (0.37, 0.30-0.44) were less likely for HTOs than UKAs. Postoperative admission to intensive care unit was significantly lower with HTO (odds ratio: 0.40, 0.29-0.54) while rehospitalization within 30 days (1.27, 1.16-1.38) and 90 days (1.24, 1.18-1.30) were higher than UKA.

CONCLUSION

When choosing the surgical method for unicompartmental knee OA, not only the survival rate, but also the risk of other adverse outcomes should be considered. In particular, attention should be paid to the risk of developing deep vein thromboembolism and surgical site infection.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s43465-021-00517-z.

Does postoperative quantitative bone scintigraphy reflect outcomes following medial open-wedge high tibial osteotomy?

Purpose

The present study evaluated changes in bone tracer uptake (BTU) after medial open-wedge high tibial osteotomy (MOWHTO) and determined whether postoperative BTU correlates with clinical symptoms, radiologic parameters, or cartilage regeneration following MOWHTO.

Methods

A total of 210 knees underwent MOWHTO for medial compartmental osteoarthritis (OA) were enrolled in this study. Mean follow-up period was 42.7 months. We assessed BTU for the medial compartment of the knee before MOWHTO and at the time of plate removal. Radiologic parameters included Kellgren-Lawrence (K-L) grade and Hip-Knee-Ankle angle (HKAA). Clinical evaluation included American Knee Society (AKS) score and cartilage status was graded at the time of MOWHTO and second-look arthroscopy according to the International Cartilage Repair Society (ICRS) grading system and articular cartilage regeneration stage. Statistical analysis performed to assess the relationships among postoperative BTU of the medial compartment, radiologic parameters, arthroscopic changes and clinical outcomes.

Results

BTU of medial femoral condyle and tibial plateau were significantly decreased at 2 years after MOWHTO (p<0.001). AKS scores and arthroscopic cartilage status were also significantly improved following MOWHTO. BMI and postoperative HKAA showed significant correlations with postoperative changes of BTU in uni- and multi-variable analysis. Meanwhile, postoperative changes of BTU did not show significant correlation with clinical outcomes or cartilage regeneration following MOWHTO.

Conclusion

Lower BMI and postoperative valgus alignment were significant predictor for postoperative BTU decrease of the medial compartment following MOWHTO. However, postoperative changes of BTU did not reflect cartilage regeneration or clinical outcomes until the midterm follow-up.

Contemporary Knee Osteotomy in the United States: High Tibial Osteotomy and Distal Femoral Osteotomy Have Comparable Complication Rates despite Differing Demographic Profiles

Knee osteotomies show efficacy in slowing knee osteoarthritis progression and delaying the need for total knee arthroplasty in younger patients. Despite evolutions in indications, techniques, and hardware that have improved outcomes, longitudinal trends demonstrate a decline in high tibial osteotomy (HTO) and distal femoral osteotomy (DFO) use. Unfortunately, knowledge of the current usage and complications associated with HTO and DFO is limited. The purpose of this study was to compare the preoperative demographics and early complication rates of HTO and DFO. We analyzed the HTOs and DFOs performed between 2006 and 2017 using the ACS-NSQIP (American College of Surgeons National Surgical Quality Improvement Program) database. We compared both groups for preoperative patient demographics (sex, age, race, body mass index [BMI]) and health status variables including functional scores, ASA (American Society of Anesthesiologists) scores, smoking status, and other comorbidities. Emergency and elective status of the patient case, length of hospital stay, operation time, and 30-day postoperative complications were also analyzed. After the exclusion criteria were applied, 321 HTO and 295 DFO patients were included in the final analysis. The HTO group had higher proportions of younger (p < 0.001) and male (p < 0.001) patients with higher BMI (p = 0.007). Racial profiles were similar between the two groups (p = 0.575). Preoperatively, those in the HTO group had more functional independence, better physical status scores, and fewer chronic conditions (p < 0.05). There were no statistically significant differences between HTO and DFO in operative time, postoperative complications, readmission, and reoperation. HTO patients, however, had shorter hospital stays (p < 0.001). Although there are differences in preoperative and operative characteristics of HTO and DFO, early postoperative complications are similar for both groups. Therefore, HTO and DFO can be considered safe and effective treatment options for younger patients with symptomatic unicompartmental knee osteoarthritis.

Do We Need Chemoprophylaxis to Prevent Venous Thromboembolism following Medial Open-Wedge High Tibial Osteotomy?

The aim of this study was to investigate the overall incidence of venous thromboembolism (VTE) and to assess the efficacy of chemoprophylaxis to prevent VTE following medial open-wedge high tibial osteotomy (MOWHTO) in Asian patients. A total of 133 patients who consecutively underwent MOWHTO for the treatment of knee osteoarthritis with varus deformity were enrolled. All patients underwent preoperative ultrasonography and computed tomography venography on postoperative day 5 to detect deep vein thrombosis (DVT). Patients were divided into two groups: chemoprophylaxis group included patients (n = 66) who received 2.5 mg fondaparinux for 5 days postoperatively, whereas control group comprised patients (n = 67) who received placebo (67 patients). We evaluated the efficacy and safety outcomes of the treatment. We also assessed the predisposing factors that may affect the occurrence of VTE. The incidence of overall DVT was 14.9% in the control group and 10.6% in the chemoprophylaxis group (p > 0.05). Proximal DVT occurred in one patient in the control group. There was no symptomatic DVT or pulmonary embolism in either group. The patients with DVT had significantly higher mean body mass index (BMI) than the patients without DVT. Multivariate logistic regression showed BMI > 30 kg/m² that was significantly correlated with the development of DVT (odds ratio = 0.8; p = 0.017). There were no cases of major bleeding; however, minor bleeding episodes occurred in four patients in the chemoprophylaxis group. The current study showed that the overall incidence of VTE following MOWHTO was low in Asian patients even without chemoprophylaxis. Therefore, routine chemoprophylaxis following MOWHTO seems to be not necessary in a population with low-VTE incidence. However, selective chemoprophylaxis should be considered in patients with BMI > 30 kg/m².

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.

Comparison of Long-Term Survival Analysis Between Open-Wedge High Tibial Osteotomy and Unicompartmental Knee Arthroplasty

BACKGROUND

To compare unicompartmental knee arthroplasty (UKA) and open-wedge high tibial osteotomy (OWHTO) in a long-term follow-up propensity score matching analysis.

METHODS

Patients who underwent UKA or OWHTO for unilateral medial unicompartmental osteoarthritis (OA) between 2004 and 2010 were included. The ROM, HSS score, KS score, WOMAC score, forgotten joint score, OA progression in patellofemoral and lateral compartments, and survivorship were compared within ten years of follow-up between 67 UKA and 67 OWHTO patients after propensity score matching for age, gender, body mass index, range of motion, and osteoarthritis (OA) grade.

RESULTS

At the last follow-up, there were no significant differences between the two groups in clinical outcomes, but the WOMAC score showed better results after UKA (13.1 in UKA vs 18.9 in OWHTO, P = .011). The OA progression also showed no significant difference between the two groups. After a 10-year follow-up, the survival rate was higher in UKA patients (96.2%) than in OWHTO patients (87.7%), with no statistical difference (P = .06).

CONCLUSION

UKA showed better clinical outcomes and OA progressions than OWHTO. The survival rate presented a superiority of 8.5% for the UKA group in the 10-year follow-up, without significant difference.

Patient-specific instrumentation (PSI) Referencing High Tibial Osteotomy Technological Transfer and Education: protocol for a double-blind, randomised controlled trial (PROTECTED HTO Trial)

INTRODUCTION

High tibial osteotomy (HTO) is a treatment of choice for active adult with knee osteoarthritis. With advancement in CT imaging with three-dimensional (3D) model reconstruction, virtual planning and 3D printing, patient-specific instrumentation (PSI) in form of cutting jigs is employed to improve surgical accuracy and outcome of HTO. The aim of this randomised controlled trial (RCT) is to explore the surgical outcomes of HTO for the treatment of medial compartment knee osteoarthritis with or without a 3D printed patient-specific jig.

METHODS AND ANALYSIS

A double-blind RCT will be conducted with patients and outcome assessors blinded to treatment allocation. This meant that neither the patients nor the outcome assessors would know the actual treatment allocated during the trial. Thirty-six patients with symptomatic medial compartment knee osteoarthritis fulfilling our inclusion criteria will be invited to participate the study. Participants will be randomly allocated to one of two groups (1:1 ratio): operation with 3D printed patient-specific jig or operation without jig. Measurements will be taken before surgery (baseline) and at postoperatively (6, 12 and 24 months). The primary outcome includes radiological accuracy of osteotomy. Secondary outcomes include a change in knee function from baseline to postoperatively as measured by three questionnaires: Knee Society Scores (Knee Scores and Functional Scores), Oxford Knee Scores and pain visual analogue scale (VAS) score.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Joint Chinese University of Hong Kong - New Territories East Cluster Clinical Research Ethics Committee (CREC no. 2019.050), in accordance with the Declaration of Helsinki. The results will be presented at international scientific meetings and through publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04000672; Pre-results.

Medial Meniscus Posterior Root Tear Does Not Affect the Outcome of Medial Open-Wedge High Tibial Osteotomy

BACKGROUND

This study aimed to verify whether the presence of medial meniscus posterior root tear (MMPRT) affects the clinical and radiographic outcomes of medial open-wedge high tibial osteotomy (MOWHTO) compared to the patients without MMPRT for over a midterm follow-up.

METHODS

One hundred fifty-six knees were retrospectively enrolled that underwent MOWHTO and second-look arthroscopy concomitantly with a minimum 5 years of follow-up. Seventy-four knees with MMPRT (MMPRT group) were identified. Eighty-two knees with intact MMPR were assigned to another group (MMPRI group). All knees with torn medial meniscus with or without MMPRT had an arthroscopic partial meniscectomy during the MOWHTO. Clinical evaluation included range of motion, American Knee Society scores, and Western Ontario and McMaster Universities Osteoarthritis Index scores. Radiologically, the Kellgren-Lawrence grade was assessed preoperatively and at the latest follow-up. Cartilage status was also compared through the 2-stage arthroscopy according to the International Cartilage Repair Society grading.

RESULTS

Average age at operation was 55.8 years (range 42-67), and the average follow-up period was 82.2 months (range 60-148). There were no significant differences in clinical outcomes between the groups. Postoperative changes in Kellgren-Lawrence grade and arthroscopic cartilage status showed no significant differences between the groups. Resected MMPR was remodeled in 41.9% (31/74) of the MMPRT group through the second-look arthroscopy.

CONCLUSION

MMPRT does not affect the clinical and radiologic outcomes of MOWHTO compared to those patients without MMPRT over a mid-term follow-up.

Current Trends and Projected Burden of Primary and Revision Total Knee Arthroplasty in Korea Between 2010 and 2030

BACKGROUND

This study aimed to (1) document the total knee arthroplasty (TKA) use in Korea from 2010 to 2018, (2) evaluate whether rapid increase in TKA use has been maintained, and (3) estimate the projected TKA burden to 2030 based on the current use.

METHODS

Using the Health Insurance Review and Assessment Korean database, procedural rate, growth rate, and revision burden of primary and revision TKAs in Korea between 2010 and 2018 were analyzed. TKA procedural numbers were also stratified by age and gender. Then, the projected TKA burden to 2030 including procedural number and medical costs were estimated using linear and quasi-Poisson regression models, respectively.

RESULTS

Between 2010 and 2018, procedural rate of primary and revision TKAs has increased by 35% and 68%, respectively. More than 85% of primary and revision TKAs were performed on female patients, and the subgroup of patients aged ≥80 years showed a marked increase in primary and revision TKA use. According to the projection model, the number of primary and revision TKAs is predicted to increase between 53% and 91%, and between 75% and 155%, respectively, by 2030.

CONCLUSION

Between 2010 and 2018, the procedural rates of primary and revision TKAs in Korea increased gradually by 35% and 68%, respectively, and previously observed striking growth rate has markedly slowed. Nevertheless, compared to 2018, the burdens of primary and revision TKAs are projected to increase up to 91% and 155%, respectively, by 2030.

LEVEL OF EVIDENCE

Therapeutic Level III.

Is Mobile-Bearing Medial Unicompartmental Knee Arthroplasty Appropriate for Asian Patients With the Risk of Bearing Dislocation?

BACKGROUND

Mobile-bearing unicompartmental knee arthroplasty (UKA) is an attractive operation for medial unicompartmental knee arthritis, but unexpected bearing dislocation is a drawback. Bearing dislocation occurs more frequently in Asians, whose lifestyle involves deeper knee flexion than Westerners. This study investigated whether mobile-bearing medial UKA is appropriate for Asians by analyzing (1) the rate of bearing dislocation and (2) the results of patients with bearing dislocation.

METHODS

We retrospectively reviewed 531 consecutive mobile-bearing medial UKA in the previous 15 years, including 22 patients with bearing dislocation who had at least 2 years of follow-up. The entire patient cohort was divided into 2 groups: the symmetrical bearing (187 knees) and the anatomic bearing (344 knees) groups. In the anatomic bearing group, patients who underwent surgery using the conventional phase III (283 knees) vs the Microplasty (61 knees) instrumentation systems were compared.

RESULTS

The overall incidence of bearing dislocation was 4.1% (22/531). Patients with the symmetrical bearing displayed a relatively high dislocation rate of 9.6% (18/187), which significantly decreased to 1.1% (4/344) after changing to the anatomic bearing (P < .001). In the anatomic bearing group, the dislocation rate with the conventional phase III system was 1.4% (4/283). There were no bearing dislocations in the Microplasty system group (0%, 0/61) after at least 2 years of follow-up.

CONCLUSION

Although mobile-bearing medial UKA was reported to have a high incidence of bearing dislocation in Asians, this frequency of dislocation is drastically decreased by bearing design and implantation system improvements. We consider mobile-bearing medial UKA appropriate for Asians.

What Factors Predict Patient Dissatisfaction After Contemporary Medial Opening-Wedge High Tibial Osteotomy?

BACKGROUND

Although current advances in surgical techniques have improved outcomes of the medial opening-wedge high tibial osteotomy (MOWHTO), the factors associated with patient dissatisfaction remain unclear. Thus, the purpose of this study is to identify risk factors for patient dissatisfaction following contemporary MOWHTO.

METHODS

We retrospectively reviewed prospectively collected data on 140 consecutive MOWHTO patients using an anatomical locking plate with a minimum follow-up of 2 years. Patient demographics, pain Visual Analogue Scale, Western Ontario and McMaster Universities Osteoarthritis Index, Kellgren-Lawrence (K-L) grade, activity level, articular cartilage and meniscal status, hip-knee-ankle angle, change in alignment, and postoperative weight-bearing line ratio were recorded. Patients were categorized using the New Knee Society Score into satisfied (satisfaction score ≥20) or dissatisfied (satisfaction score <20) groups. Patient and surgical factors were compared between the groups by the identified predictors. Multiple logistic regression analysis was used to analyze risk factors, including K-L grade IV medial osteoarthritis (OA), preoperative pain Visual Analogue Scale, total Western Ontario and McMaster Universities Osteoarthritis Index score, postoperative hip-knee-ankle angle, change in alignment, and partial meniscectomy.

RESULTS

Of the 140 patients, 24 (17.1%) were dissatisfied with their results. Multiple logistic regression analysis showed that only K-L grade IV medial OA was statistically associated with patient dissatisfaction following MOWHTO (odds ratio 4.911, 95% confidence interval 1.820-13.256, P < .01).

CONCLUSION

Severe medial OA was an independent risk factor for dissatisfaction following contemporary MOWHTO using a rigid locking plate. Surgeons should take this into consideration when counseling and choosing surgical options in MOWHTO candidates with severe medial OA.

LEVEL OF EVIDENCE

Level III.

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.

Lateral numbness in the lower leg: An underestimated complication following medial open-wedge high tibial osteotomy

BACKGROUND

This study aimed to investigate the incidence, degree, and natural course of lateral numbness following medial open-wedge high tibial osteotomy (MOWHTO). It also evaluated which predisposing factors would affect lateral numbness following MOWHTO.

METHODS

One-hundred and sixty-nine knees that underwent MOWHTO for treatment of varus osteoarthritis with a minimum follow-up of three years were enrolled. Lateral numbness in the lower leg was assessed with the light-touch method using a cotton wool ball and compared with the contralateral leg. Patients were classified into groups based on a scale according to grading of sensation to light touch. To assess the improvement of lateral numbness, lower leg sensation was investigated using a sensory score compared with the contralateral leg. The predisposing factors that would affect lateral numbness were assessed.

RESULTS

Lateral numbness was observed in 87 knees (51.5%) at six weeks postoperatively. Although 69 knees improved over time, 18 knees showed no improvement to the latest follow-up. The level of skin incision showed a significant association with lateral numbness on univariate and multivariate analyses: the higher the level of skin incision, the greater the degree of estimated numbness.

CONCLUSIONS

About half the patients reported postoperative lateral numbness in the lower leg following MOWHTO. Of the patients with lateral numbness, approximately one-fifth remained symptom until the last follow-up. The level of skin incision might be a risk factor for lateral numbness. Pre-operative patient education concerning the likelihood of lateral numbness is recommended.

LEVEL OF EVIDENCE

Level IV, case series.

Mid-term Clinical and Radiological Results of Oxford Phase 3 Medial Unicompartmental Knee Arthroplasty

Introduction The popularity of unicompartmental knee arthroplasty (UKA) for the treatment of isolated compartment osteoarthritis of the knee has risen over the past two decades. Currently, UKA covers a considerable amount of all knee arthroplasties worldwide. The aim of this study was to present the clinical and radiological outcomes of UKA in patients with medial compartment osteoarthritis. Methods Between January 2010 and January 2014, mobile-bearing UKA was applied to 44 knees of 37 (three men, 34 women) patients with isolated medial compartment osteoarthritis. The mean age, body mass index (BMI), and follow-up were 54 ± 6.1, 26.3± 2.2, and 48 ± 9.4, respectively. Oxford Knee Score (OKS), Knee Society Score (KSS), visual analog scale (VAS), and range of motion (ROM) were used for clinical assessment, and the Oxford Radiological Evaluation Criteria were used for radiological assessment. Results Compared to preoperative values, knee flexion increased from 116° to 123° (p<0.001). Statistically significant increases in OKS and KSS and decrease in VAS was obtained postoperatively (p<0.001). All of the components were aligned within the acceptable ranges radiologically. One bearing dislocation was revised and one conversion to TKA was performed during the 5.9-year follow-up. No major complications occurred, including infection, deep vein thrombosis, pulmonary emboli, and neurovascular injury. Conclusion The mid-term clinical and radiological outcomes of UKA were excellent in this study, and our results demonstrate that Oxford mobile-bearing UKA for the proper indication is effective, with considerable success in the treatment of medial compartmental knee osteoarthritis, regardless of age.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Total Knee Arthroplasty After High Tibial Osteotomy Results in Excellent Long-Term Survivorship and Clinical Outcomes

BACKGROUND

Some prior reports of total knee arthroplasty after high tibial osteotomy have shown high rates of aseptic loosening. As such, the goal of this study was to analyze the outcomes of contemporary total knee arthroplasty after high tibial osteotomy, with particular emphasis on survivorship free from aseptic loosening, any revision, and any reoperation; complications; radiographic results; and clinical outcomes.

METHODS

We retrospectively reviewed 207 patients who underwent 231 total knee arthroplasties using cemented prostheses after high tibial osteotomy from 2000 to 2012 through our total joint registry: 87% were after a closing-wedge osteotomy and 13% were after an opening-wedge osteotomy. The mean follow-up from total knee arthroplasty was 8 years. At the time of the total knee arthroplasty, the mean age was 64 years and the mean body mass index was 31 kg/m. The majority of total knee arthroplasties had a posterior-stabilized design (93%), and 4% had a varus-valgus constraint design. Tibial stems were utilized in 8% of cases. Bivariate and multivariate Cox regression analyses were utilized to analyze risk factors for poorer survival.

RESULTS

At 10 years, survivorship free from aseptic loosening was 97%, survivorship free from any revision was 90%, and survivorship free from any reoperation was 85%. Fifteen patients (15 total knee arthroplasties [6%]) underwent aseptic revision, most commonly for instability (3%), aseptic loosening (2%), and periprosthetic fracture (1%). On bivariate analysis, patient age of <60 years was a significant risk factor for poorer revision-free survival (hazard ratio, 2.9; p = 0.02); on multivariate analysis, younger age was the only significant risk factor for revision (p = 0.04). There were 14 complications (6%), the most common being a manipulation under anesthesia in 9 cases (4%). No unrevised total knee arthroplasties had definitive radiographic evidence of loosening. Knee Society scores improved from a mean preoperative score of 59 points to a mean postoperative score of 93 points (p < 0.001).

CONCLUSIONS

Contemporary total knee arthroplasty with a cemented prosthesis after high tibial osteotomy demonstrated excellent long-term durability, with 10-year survivorship free from aseptic loosening of 97%. There was reliable improvement in clinical outcomes, but perfect knee balance was sometimes challenging, as reflected by a 4% prevalence of manipulation under anesthesia and a 3% prevalence of revision for instability.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Pneumatic compression device does not show effective thromboprophylaxis following total knee arthroplasty in a low incidence population

INTRODUCTION

Purpose of this study was to assess whether the intermittent pneumatic compression (IPC) device would be an effective prophylaxis for deep vein thrombosis (DVT) following total knee arthroplasty (TKA) in a low incidence population.

HYPOTHESIS

The mechanical thromboprophylaxis could reduce the incidence of DVT compared to non-prophylaxis group and would have similar efficacy as the chemoprophylaxis following TKA in a low DVT incidence population.

MATERIALS AND METHODS

From January 2009 to June 2016, 1259 elective primary TKA with preoperative diagnosis of primary osteoarthritis in a single institute were enrolled. Patients were divided into three groups: those who were managed with chemoprophylaxis (CPX group, 414 cases), with mechanical prophylaxis (IPC group, 425 cases), or without pharmacological and mechanical prophylaxis (control group, 420 cases). All patients underwent preoperative ultrasonography and computed tomographic venography on postoperative day 6 to assess development of DVT. The incidence of overall, proximal, symptomatic DVT and symptomatic pulmonary embolism (PE) were compared among the groups. Major and minor bleeding complications were also evaluated.

RESULTS

The incidence of overall DVT was 14.8% in control group, 6.3% in CPX group and 11.3% in IPC group respectively and CPX group showed significantly lower incidence than other two groups (p<0.001). The incidence of proximal DVT was 1.9% in control group, 0.7% in CPX group and 0.9% in IPC group respectively (p>0.05). The incidence of symptomatic DVT was 0.7% in control group, 0% in CPX group and 0.7% in IPC group respectively (p>0.05). There was no case of symptomatic PE diagnosed during hospital stay in all patients.

DISCUSSION

Single use of IPC device could not reach significant level of DVT prophylaxis compared to control group and only chemoprophylaxis showed significantly reduce the incidence of overall DVT following TKA. Single use of IPC device does not show effective thromboprophylaxis in a low DVT incidence population.

LEVEL OF EVIDENCE

III, case control study.

Predictive factors for satisfaction after contemporary unicompartmental knee arthroplasty and high tibial osteotomy in isolated medial femorotibial osteoarthritis

INTRODUCTION

Both high tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) are viable treatment options for early osteoarthritis (OA). Although a substantial proportion of the patient selection criteria for HTO and UKA are now shared, the factors related to satisfaction following each procedure remain unclear.

HYPOTHESIS

We hypothesized that patient factors associated with satisfaction following contemporary HTO and UKA would be different.

MATERIAL AND METHODS

We retrospectively reviewed the records of consecutively enrolled medial opening-wedge HTOs (n=123) and Oxford mobile-bearing UKAs (n=118) with satisfactory postoperative alignment. Preoperative demographics, physical activity levels, varus deformity status, and degree of OA were recorded. Postoperative radiographs, frequency of combined procedures and patient-reported outcomes (PROs) including pain, Western Ontario and McMaster Universities Osteoarthritis Index score, and patient satisfaction were assessed.

RESULTS

Severe OA (p<0.01) was associated with an increased risk of dissatisfaction following HTO, whereas young age (p<0.01) and severe varus deformity (p=0.045) were related to dissatisfaction after UKA. In addition, patient satisfaction following UKA was higher than that following HTO in individuals with highly physically demanding activity. All UKA PROs were superior to those of the HTO group, except pain level.

CONCLUSION

Despite the shared patient selection criteria for contemporary HTO and UKA, severe OA was associated with dissatisfaction following HTO, whereas young age and varus deformity were associated with dissatisfaction following UKA. Age, varus deformity and OA severity should be considered when deciding whether to perform HTO or UKA.

TYPE OF STUDY AND LEVEL OF PROOF

Retrospective cohort study, Level III.

Late Mobile-Bearing Dislocation in Unicompartmental Knee Arthroplasty

The authors present 2 cases of late mobile-bearing dislocation after unicompartmental knee arthroplasty with long-term follow-up. Patients had anterior bearing dislocation more than 10 years after primary unicompartmental knee arthroplasty. Retrieved mobile bearings showed severe erosion on the posterior lip, suggesting frequent deep knee flexion as the cause of wear. Bearing dislocation is known to occur in the early postoperative phase. However, for Asians with a lifestyle that requires high knee flexion, dislocation might occur in the late postoperative phase. Such late bearing dislocation has a mechanism different from those reported in previous studies. Loss of bump in the posterior lip was found to be the cause. After late bearing dislocation, conversion to total knee arthroplasty is unnecessary because a simple bearing exchange will suffice. [Orthopedics. 2019; 42(1):e124-e127.].

Extra-articular Lateral Hinge Fracture Does Not Affect the Outcomes in Medial Open-Wedge High Tibial Osteotomy Using a Locked Plate System

PURPOSE

To compare the radiologic and clinical outcomes in patients with and without lateral hinge fractures (LHFs) during medial open-wedge high tibial osteotomy (MOWHTO) using a locked plate system, as well as to assess whether LHFs could affect the midterm outcomes.

METHODS

From May 2008 to November 2015, 164 knees underwent MOWHTO using a locked plate system for the treatment of knee osteoarthritis. LHFs were recognized by radiographs during or after the high tibial osteotomy and were not additionally treated. In all patients, we applied the same rehabilitation protocol that allowed full weight bearing at 6 weeks. Patients were divided into LHF (types I and II) and nonfracture groups. Radiologically, we compared any serial changes in the hip-knee-ankle angle, femorotibial angle, medial proximal tibial angle, and posterior tibial slope angle from the immediate postoperative radiographs to the final radiographs. The union process of the osteotomy site among the groups was also evaluated. Clinically, the postoperative American Knee Society Score and knee range of motion at latest follow-up were compared. Postoperative complications were also evaluated.

RESULTS

The average age at operation was 56.0 years (range, 42-67 years), and the average follow-up period was 62.2 months (range, 24-120 months). LHFs were observed in 37 knees (22.6%) and were divided into the type I (16 knees) and type II (21 knees) groups. All groups showed no significant changes in serial evaluations of the postoperative hip-knee-ankle angle, femorotibial angle, medial proximal tibial angle, and posterior tibial slope angle. The improvements in the American Knee Society Score and knee range of motion were not significantly different among the groups. No patients showed correction loss or union problems.

CONCLUSIONS

Type I and II LHFs in MOWHTO using a medial locked plate system and relatively conservative rehabilitation protocol with full weight-bearing walking commenced at 6 weeks postoperatively showed no radiologic changes or functional deterioration during midterm follow-up.

LEVEL OF EVIDENCE

Level IV, case series.

Does the pre-operative status of the anterior cruciate ligament affect the outcomes following medial open-wedge high tibial osteotomy?

BACKGROUND

This study aimed to assess the morphological degeneration of the anterior cruciate ligament (ACL) through magnetic resonance imaging (MRI) and arthroscopy. It analyzed whether the pre-operative ACL status would affect the radiologic and clinical outcomes following medial open-wedge high tibial osteotomy (MOWHTO).

METHODS

A total of 150 knees were enrolled that underwent MOWHTO concomitant arthroscopic debridement for the treatment of varus osteoarthritis. Mean age was 56.1 ± 5.0 years and mean follow-up was 61.2 ± 21.4 months. The ACLs were staged based on MRI and arthroscopy. To exclude the influence of demographic factors on outcomes, the between-group differences were assessed. Radiologic evaluation included hip-knee-ankle angle, femorotibial angle, medial proximal tibial angle, posterior tibial slope angle, and Kellgren-Lawrence grade. Clinical evaluation included American Knee Society Score (AKSS) and knee joint range of motion (ROM).

RESULTS

The ACLs were classified into intact (75 knees, 50.0%), mucoid degeneration (59, 39.3%), chronic partial tear (10, 6.7%), and complete tear (six, 4.0%) according to MRI. They were also classified into four stages: normal (95 knees, 63.3%), abnormal (36, 24.0%), partial tear (13, 8.7%), and complete tear (six, 4.0%) according to arthroscopic appearance. There were no significant between-group differences in each variable. Changes in Kellgren-Lawrence grade did not show significant between-group differences. No significant between-group differences were observed in AKSS and ROM.

CONCLUSIONS

The pre-operative status of ACL did not influence the outcomes following MOWHTO at midterm follow-up.

LEVEL OF EVIDENCE

Level IV, case series.

Cost-effectiveness of lumbar fenestration surgery in the Japanese universal health insurance system

BACKGROUND

Healthcare costs are a global concern, and cost-effectiveness analyses of interventions have become important. However, data regarding cost-effectiveness are limited to a few medical fields. The purpose of our study was to examine the Japanese universal health insurance system cost per quality-adjusted life year (QALY) for lumbar fenestration surgery.

METHODS

Forty-eight patients who underwent fenestration for lumbar degenerative spinal canal stenosis between July 2013 and September 2015 were included. Effectiveness was evaluated by measuring the EuroQOL 5-dimension (EQ-5D), Short-Form 8 physical component summary (PCS), and visual analog scale (VAS). Cost was analyzed from the perspective of the public healthcare payer. Effectiveness and cost were measured 1 year after surgery. QALYs were calculated by multiplying the utility value (EQ-5D) and life years. Only direct costs based on actual reimbursements were included. Cost per QALY with a 5-year time horizon with a 2% discount rate was estimated. Sensitivity analysis was performed by varying the time horizon (2 years or 10 years).

RESULTS

Mean total cost 1 year after fenestration surgery was 1,254,300 yen (standard deviation [SD], 430,000 yen; median, 1,172,300 yen). Operative cost was 406,800 yen (SD, 251,500 yen; median, 363,000 yen). Mean gained score was 0.21 for EQ-5D (SD, 0.18; median, 0.24), 11 for PCS (SD, 10; median, 12), and -43 for VAS (SD, 34; median, -38). Cost per QALY was 1,268,600 yen. Sensitivity analysis demonstrated that cost per QALY with a 10-year time horizon was 679,300 yen and that with a 2-year time horizon was 3,004,600 yen.

CONCLUSIONS

Cost per QALY of lumbar fenestration with a 5-year time horizon was 1,268,600 yen (11,532 US dollar), which was below the widely accepted benchmark (cost per QALY <5,000,000-6,500,000 yen (50,000 US dollars)). Fenestration is a cost-effective intervention.

Tranexamic acid is effective for blood management in open-wedge high tibial osteotomy

INTRODUCTION

There has been paucity in literature regarding the blood-sparing effect of TXA after high tibial osteotomy (HTO). The purpose of this study is to determine the efficacy of tranexamic acid (TXA) with regard to its blood-sparing effects in open-wedge HTO, and to assess thromboembolic complications in patients undergoing open-wedge HTO with or without the use of TXA.

HYPOTHESIS

The intravenous TXA would reduce postoperative blood loss and transfusion requirements without increasing thromboembolic complications in open-wedge HTO.

MATERIALS AND METHODS

From March 2011 to December 2016, medial open-wedge HTO was performed in 150 consecutive knees with varus gonarthrosis. The mean age at the time of surgery was 55.3±5.0 years. TXA was intravenously used in the latter 75 knees (TXA group), and the group was retrospectively compared with the former 75 knees without use of TXA (control group). Outcome measures were postoperative hemoglobin drop, drain amount, total estimated blood loss, transfusion requirements, and incidence of thromboembolic complications.

RESULTS

The use of TXA led to a significant decrease in hemoglobin drop (p<0.001) and drain amount (p=0.025). Total estimated blood loss was lower in the TXA group than in the control group (p<0.001). Two knees in the control group had postoperative blood transfusion, compared to none in the TXA group (p>0.05). There were no thromboembolic complications such as symptomatic deep vein thrombosis and pulmonary embolism in both groups.

CONCLUSION

The use of TXA reduced perioperative hemoglobin drop, drain amount, and total estimated blood loss without thromboembolic complications in patients undergoing open-wedge HTO. Therefore, the use of TXA is a safe and viable option for perioperative blood management in open-wedge HTO.

LEVEL OF EVIDENCE

III, Case control study.

High tibial osteotomy accelerates lateral compartment osteoarthritis in discoid meniscus patients

PURPOSE

The valgus high tibial osteotomy (HTO) in patients with medial osteoarthritis and discoid lateral meniscus can result in increased load on the lateral compartment and hence a higher chances of tear. This may accelerate the progression of osteoarthritis on lateral compartment. We, therefore, carried out the case control study with a hypothesis that an HTO would accelerate the progression of osteoarthritis (OA) on lateral compartment in patients with complete discoid meniscus.

METHODS

The records of all patients with open wedge HTO from 2008 to 2012 were evaluated for complete lateral discoid meniscus. The patient who had a valgus HTO with or without partial meniscectomy for medial compartmental OA was included for this study. Cases to control were chosen to match age, body mass index (BMI), pre-operative osteoarthritis grade, and deformity angles in ratio 1:2. Patient's records were studied for demographic data, clinical examination records, and pre-operative knee functional scores and radiological scores and were compared with post-operative data.

RESULTS

Thirty-six patients out of 674 patients, who underwent an HTO, consisted of discoid meniscus group. 72 patients were chosen as control group. Four patients showed progression of OA on the lateral compartment in discoid group compared to none in control group. Although control groups showed a little bit better functional outcomes, there were no statistical differences between two groups (n.s.).

CONCLUSION

The high tibial osteotomy could result in accelerated lateral compartment osteoarthritis in patients with complete discoid meniscus, and the procedure should be used with caution in such patients.

LEVEL OF EVIDENCE

IV.

Slow gait speed after bilateral total knee arthroplasty is associated with suboptimal improvement of knee biomechanics

PURPOSE

The aim of this study was to investigate gait speed changes 2 years after bilateral total knee arthroplasty (TKA) and identify kinetic and kinematic factors associated with such changes by comparing patients with age- and sex-matched controls.

METHODS

The study group included 34 female patients with end-stage knee osteoarthritis (OA) who underwent bilateral TKA and 42 age- and sex-matched controls without knee pain or OA. Standard TKA was performed on all arthritic patients with placement of posterior stabilized fixed-bearing implants. Kinetic and kinematic parameters were evaluated using a commercial optoelectric gait analysis system. Gait speed, kinetic and kinematic changes and determinants of speed were assessed via principal component analysis and multiple regression analysis.

RESULTS

The average gait speed of an arthritic patient was 90.2 ± 18.4 cm/s and improved to 96.0 ± 12.3 cm/s after TKA (p = 0.032). However, the speed remained slower than that of controls (111.2 ± 8.2 cm/s, p < 0.001). With regard to kinetics, the peak knee extension moment (KEM) generated by the quadriceps was unchanged after TKA and weaker than that of controls (p < 0.001). The proportions of KEM contributing to the total sagittal moment were also smaller in the pre-/post-operative groups than in the control group (13-14% vs. 19%). On the other hand, the ankle plantar flexion moment (APFM) was increased after TKA (p = 0.007) and its proportion of the total sagittal moment was greater than in controls (46% vs. 42%). With regard to kinematics, knee range of motion (ROM) improved after TKA (p = 0.025), but was smaller than that of controls (p < 0.001). In controls, gait speed was determined principally by hip and knee joint moments. However, in the TKA group, speed was determined by the knee ROM and APFM.

CONCLUSIONS

Despite showing improvement, the gait speed of TKA patients remained slower than that of controls. Slow gait speed after bilateral TKA was associated with suboptimal improvement of knee biomechanics. Quadriceps strengthening exercises and the achievement of greater ROM during gait are advised for the further improvement of gait speed.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

Baseline varus deformity is associated with increased joint loading and pain of non-operated knee two years after unilateral total knee arthroplasty

BACKGROUND

The goals of this study were (1) to document the gait pattern of patients with unilateral knee osteoarthritis (OA), (2) to determine the knee adduction moment (KAM) changes in the non-operated knee, and (3) to identify the predictors of change in KAM in the non-operated knee.

METHODS

The study recruited 23 patients with advanced unilateral knee OA. The preoperative Kellgren-Lawrence (KL) grade of the non-operated knee was one or two; non-operated knee pain, rated using a numeric rating scale (NRS), was less than three out of 10 points. We used a commercial gait analysis system to evaluate kinetics and kinematics. Radiological and gait measurements at the two-year follow-up were compared with baseline data.

RESULTS

The preoperative asymmetrical gait cycle characterized by elongation of the stance phase of the non-operated knee became symmetrical after TKA. The average KAM of the non-operated knee increased (P=0.010) and it was best predicted by the baseline mechanical axis of the non-operated knee. If the baseline mechanical axis was varus four degrees or above (varus group), the average KAM increased by 0.64 (% body weight×height, P=0.015), while for varus less than four degrees (non-varus group), KAM was unchanged. The KL grade was increased in the varus group (P=0.020) but it was unchanged in the non-varus group. Average pain NRS score was also higher (P=0.044) in the varus group.

CONCLUSIONS

Close follow-up is necessary for patients with a baseline varus deformity of the non-operated knee because of the higher possibility of developing pain, subsequent arthritis and increased joint loading of the non-operated knee.

LEVEL OF EVIDENCE

III, retrospective cohort study.

The Leukocyte Esterase Strip Test has Practical Value for Diagnosing Periprosthetic Joint Infection After Total Knee Arthroplasty: A Multicenter Study

BACKGROUND

Leukocyte esterase (LE) was recently reported to be an accurate marker for diagnosing periprosthetic joint infection (PJI) as defined by the Musculoskeletal Infection Society (MSIS) criteria. However, the diagnostic value of the LE test for PJI after total knee arthroplasty (TKA), the reliability of the subjective visual interpretation of the LE test, and the correlation between the LE test results and the current MSIS criteria remain unclear.

METHODS

This study prospectively enrolled 60 patients undergoing revision TKA for either PJI or aseptic failure. Serological marker, synovial fluid, and histological analyses were performed in all cases. The PJI group comprised 38 cases that met the MSIS criteria and the other 22 cases formed the aseptic group. All the LE tests were interpreted using both visual judgment and automated colorimetric reader.

RESULTS

When "++" results were considered to indicate a positive PJI, the sensitivity, specificity, positive and negative predictive value, and diagnostic accuracy were 84, 100, 100, 79, and 90%, respectively. The visual interpretation agreed with the automated colorimetric reader in 90% of cases (Cronbach α = 0.894). The grade of the LE test was strongly correlated with the synovial white blood cell count (ρ = 0.695) and polymorphonuclear leukocyte percentage (ρ = 0.638) and moderately correlated with the serum C-reactive protein and erythrocyte sedimentation rate.

CONCLUSION

The LE test has high diagnostic value for diagnosing PJI after TKA. Subjective visual interpretation of the LE test was reliable and valid for the current battery of PJI diagnostic tests according to the MSIS criteria.

Annual trends in knee arthroplasty and tibial osteotomy: Analysis of a national database in Japan

BACKGROUND

Various nationwide studies have reported differing annual trends in utilization of knee arthroplasty and tibial osteotomy. Using the Diagnosis Procedure Combination database in Japan, the present series examined annual trends and demographics in total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA) and tibial osteotomy.

METHODS

All patients were identified who underwent TKA, UKA or tibial osteotomy for osteoarthritis, osteonecrosis or rheumatoid arthritis of the knee between July 2007 and March 2015.

RESULTS

A total of 170,433 cases of TKA, 13,209 cases of UKA and 8760 cases of tibial osteotomy were identified. The proportion of patients undergoing UKA rose from 4.0% in 2007 to 8.1% in 2014 (P<0.001), and that of tibial osteotomy from 2.6% in 2007 to 5.5% in 2014 (P<0.001); the proportion undergoing TKA fell from 93.4% in 2007 to 86.3% in 2014 (P<0.001). Between 2007 and 2014 the proportions of patients with osteonecrosis who underwent UKA and tibial osteotomy increased from 34.7% and 11.6% to 38.6% and 16.2%, respectively (P=0.001 for UKA and P=0.004 for tibial osteotomy). The proportions of patients with osteonecrosis undergoing UKA or tibial osteotomy were significantly greater than those with other diagnoses (P<0.001 for both).

CONCLUSIONS

The popularity of UKA and tibial osteotomy in Japan increased during the period 2007-2014 at the expense of TKA. The proportions of UKA and tibial osteotomy in patients with osteonecrosis also increased, and were larger than those in patients with other causative diseases.

Collagen Augmentation Improves the Quality of Cartilage Repair After Microfracture in Patients Undergoing High Tibial Osteotomy: A Randomized Controlled Trial

BACKGROUND

The quality of cartilage repair after marrow stimulation is unpredictable. To overcome the shortcomings of the microfracture technique, various augmentation techniques have been developed. However, their efficacies remain unclear.

HYPOTHESIS

The quality of cartilage repair and clinical outcomes would be superior in patients undergoing high tibial osteotomy (HTO) with microfracture and collagen augmentation compared to those undergoing HTO with microfracture alone without collagen augmentation for the treatment of medial compartment osteoarthritis (OA) of the knee.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

Twenty-eight patients undergoing HTO were randomized into 2 groups: microfracture alone (group 1, n = 14) or microfracture with collagen augmentation (group 2, n = 14). At 1 year postoperatively, second-look arthroscopic surgery and biopsy of repaired cartilage were performed at the time of HTO plate removal. Biopsy specimens were graded using the International Cartilage Repair Society Visual Assessment Scale II (ICRS II). In addition, imaging outcomes in terms of the magnetic resonance observation of cartilage repair tissue (MOCART) score were assessed based on magnetic resonance imaging (MRI). Finally, clinical outcomes in terms of the visual analog scale (VAS) for pain score, Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) score, and Tegner activity scale score were evaluated.

RESULTS

The mean ICRS II score in group 2 was significantly higher than that in group 1 (1053.2 vs 885.4, respectively; P = .002). Group 2 showed greater improvement in tissue morphology, cell morphology, surface architecture, middle/deep zone assessment, and overall assessment compared with group 1 ( P < .050 for all comparisons). Imaging outcomes based on the MOCART score were superior in group 2 compared to those in group 1 on MRI at 1 year postoperatively (64.6 vs 45.4, respectively; P = .001). The degree of defect repair was better in group 2 than in group 1 ( P = .040). Clinical outcomes in terms of the VAS for pain score, KOOS, IKDC score, and Tegner activity scale score were improved in both groups without between-group differences ( P > .100 for all comparisons).

CONCLUSION

The quality of cartilage repair after microfracture with collagen augmentation was superior to that after microfracture alone in patients undergoing HTO. Clinical results after 1 year did not reflect this difference in tissue repair. Therefore, a longer follow-up of the cohort is needed to answer this question.

Mid-Term Results of Oxford Medial Unicompartmental Knee Arthroplasty in Young Asian Patients Less than 60 Years of Age: A Minimum 5-Year Follow-up

Purpose

The purpose of this study was to evaluate the efficacy of unicompartmental knee arthroplasty (UKA) in young active Asian patients by analyzing clinical outcomes, complications and survival rates.

Materials and Methods

Eighty-two knees were evaluated with a minimum follow-up of 5 years after Oxford phase 3 UKA in patients less than 60 years of age at the time of surgery. Their mean age was 54.7 years (range, 44 to 59 years). The mean follow-up period was 8.9 years (range, 5.3 to 12 years). Kaplan-Meier survivorship analysis was used to estimate implant survival.

Results

Including 3 bearing dislocations, 1 medial tibial collapse and 1 lateral osteoarthritis, the total complication rate was 6.1% (5/82). Of the 3 cases of bearing dislocation, 2 cases were resolved by replacing with a thicker bearing and 1 case was converted to total knee arthroplasty (TKA) due to repeated dislocation. The two knees with a medial tibial collapse and a lateral osteoarthritis were converted to TKA. The 10-year cumulative survival rate using Kaplan-Meier survival method was 94.7% (95% confidence interval: 88.7%-100%).

Conclusions

Oxford medial UKA was reliable and effective in young active Asian patients providing good clinical results and survival rate in the mid-term follow-up.

Does Patient Perception Differ Following Adductor Canal Block and Femoral Nerve Block in Total Knee Arthroplasty? A Simultaneous Bilateral Randomized Study

BACKGROUND

Femoral nerve block (FNB) has been used as part of the multimodal analgesia after total knee arthroplasty (TKA), but leads to weakness in the quadriceps muscles. Recently, adductor canal block (ACB) was reported to provide effective pain relief while sparing the strength of the quadriceps. This simultaneous bilateral randomized study investigated whether patients perceived differences between ACB and the FNB after same-day bilateral TKA.

METHODS

We performed a prospective simultaneous bilateral randomized study in 50 patients scheduled to undergo same-day bilateral TKA. One knee was randomly assigned to ACB and the other knee was assigned to FNB. All ACB and FNB were performed using ultrasound-guided single-shot procedures. These 2 groups were compared for pain visual analogue scale, straight leg raising ability and knee extension while sitting, and motor grade. At postoperative week 1, the peak torque for the quadriceps muscle was measured in both knees with an isokinetic dynamometer.

RESULTS

There were no differences in pain levels between ACB and FNB during the entire study period. During the first 48 h after TKA, more of the knees that received ACB could perform straight leg raising and knee extension with greater quadriceps strength compared with FNB. However, no group differences in quadriceps functional recovery were found after postoperative 48 h and isometric quadriceps strength at postoperative 1 week.

CONCLUSION

This simultaneous bilateral randomized study demonstrates that patients did not perceive differences in pain level, but experienced substantial differences in quadriceps strength recovery between knees during the first 48 h (Identifier: NCT02513082).

Medial Open-Wedge High Tibial Osteotomy May Adversely Affect the Patellofemoral Joint

PURPOSE

To evaluate 2-stage arthroscopic findings of the patellofemoral joint before and after medial open-wedge high tibial osteotomy (HTO) and verify whether the patellofemoral joint would be influenced by medial open-wedge HTO.

METHODS

We prospectively reviewed 114 cases of medial open-wedge HTO for the treatment of osteoarthritis with a varus knee. First-look arthroscopy was performed during HTO. The mean age at the time of HTO was 56.34 ± 5.4 years (range, 40-69 years). Second-look arthroscopy was performed concomitantly with plate removal at an average of 26.1 ± 6.0 months (range, 21.6-32.0 months) after HTO. We assessed the patellofemoral joint using the International Cartilage Repair Society (ICRS) grading system by first- and second-look arthroscopy and compared it before and after HTO. Postoperative anterior knee pain was also evaluated.

RESULTS

Compared with first-look findings, second-look arthroscopic ICRS grading was changed as follows: In terms of the patella, 89 cases (78.1%) were not progressed whereas 25 cases (21.9%) were progressed. In terms of the femoral trochlea, 67 cases (58.8%) were not progressed whereas 47 cases (41.2%) were progressed. There was significant progression of the ICRS grade of the patella (P = .001) and femoral trochlea (P < .001) compared with first-look arthroscopic findings. The incidence of postoperative anterior knee pain was 11.4% (13 cases), and it was related to the ICRS grade of the patellofemoral joint at the time of second-look arthroscopy (P < .001 for patella and P < .001 for trochlea).

CONCLUSIONS

This study showed that the patellofemoral joint might be adversely affected by medial open-wedge HTO. Although the incidence of postoperative anterior knee pain was low, it was clinically correlated with patellofemoral arthritis.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.