Bone mineral density around the knee after open wedge high tibial osteotomy measured up to 24 months in 51 patients.

PURPOSE: To evaluate bone mineral density (BMD) and radiographic and clinical outcomes of patients with varus knee osteoarthritis treated with open wedge high tibial osteotomy (OWHTO). We hypothesised that medial condyle BMD would decrease and lateral condyle BMD would increase after OWHTO. METHODS: Overall, 51 patients (mean age: 65.3 years; female: 40, male: 11) treated with OWHTO were prospectively enrolled. Several angles using whole single-leg radiographs were measured preoperatively and up to 24 months postoperatively. Five square tibial regions of interest (ROI) located below the proximal tibia as T1-T5 from medial to lateral regions and two square femoral ROI as F1 and F2 from medial and lateral regions, respectively, were defined. M/L BMD ratio was used to define the medial-to-lateral condyle BMD ratio. Femoral condyle BMD (F1 and F2) around the knee, as well as lumbar spine, and ipsilateral and contralateral femoral neck BMD, were measured before OWHTO and 3, 6, 12 and 24 months after OWHTO using dual-energy X-ray absorptiometry. Furthermore, tibial condyle BMD (T1-T5) around the knee was measured before and 24 months after OWHTO. Clinical outcomes were evaluated using the Knee Society knee and function scores, the Knee Injury and Osteoarthritis Outcome Score, and the Lysholm score preoperatively and 24 months postoperatively. A power analysis was performed. RESULTS: F1 BMD decreased by 19.2% from before to 3 months postoperatively. F2 BMD did not change up to 24 months after OWHTO. Femoral M/L BMD ratio decreased by 22.2% 3 months after OWHTO. T1 BMD and tibial M/L BMD ratio decreased, whilst T3, T4 and T5 BMD increased 24 months after OWHTO. Mean hip-knee-ankle angle (HKA) and weight-bearing line ratio were corrected from - 6.8° to 4.5° and 14.7 to 60.7%, respectively, postoperatively. Lumbar spine BMD did not change up to 12 months postoperatively. Ipsilateral femoral neck BMD decreased up to 6 months after OWHTO. CONCLUSION: Medial femoral condyle BMD decreased rapidly within 3 months and continued to decrease up to 12 months, but lateral femoral condyle BMD did not change after OWHTO. BMD measurements around the knee condyle enabled the evaluation of the changes in stress distribution before and after OWHTO with accelerated rehabilitation. LEVEL OF EVIDENCE: II.

Status of fracture risk assessment and osteoporosis treatment in Japanese patients with rheumatoid arthritis.

OBJECTIVES: This study aimed to investigate the prevalence of patients with rheumatoid arthritis (RA) at a high risk of major osteoporosis (OP)-related fractures and the status of OP-related medical treatment for these patients. METHODS: We enrolled 120 patients aged ≥40 years (average, 69.1 years) with RA. The Fracture Risk Assessment Tool (FRAX®) was used to evaluate the fracture risk. Of the 120 patients, the femoral neck bone mineral density (BMD) was evaluated in 102 patients, and their FRAX® scores were calculated alongside the BMD values. Patients observed to be at a high risk of a major OP-related fracture (10-year probability >20% or hip fracture risk >3%), according to FRAX®, were identified as those requiring OP treatment; medication ratio for OP (percentage of patients actually receiving medication among patients requiring OP treatment) was assessed. RESULTS: OP treatment was indicated in 75 (63%) patients; the medication ratio for OP was 49%. The use of biological disease-modifying anti-rheumatic drugs and corticosteroids showed a positive effect; however, the use of methotrexate showed a negative effect on the medication ratio. CONCLUSION: The number of potential patients requiring OP treatment is underestimated. All patients with RA should be assessed to determine their eligibility for OP treatment.

Mosaic Osteochondral Autograft Transplantation Versus Bone Marrow Stimulation Technique as a Concomitant Procedure With Opening-Wedge High Tibial Osteotomy for Spontaneous Osteonecrosis of the Medial Femoral Condyle.

PURPOSE: To evaluate the effects of osteochondral autograft transplantation (OAT) mosaicplasty as a concomitant procedure with opening-wedge valgus high tibial osteotomy (HTO) for spontaneous osteonecrosis of the medial femoral condyle (MFC) on clinical outcomes and cartilage status in comparison with bone marrow stimulation (BMS) by drilling, and to assess the relation between lesion size and postoperative cartilage status. METHODS: Fifty-eight patients with spontaneous osteonecrosis of the MFC were treated with opening-wedge HTO and a concomitant procedure of BMS (28 patients) or OAT (30 patients). Clinical evaluation was carried out using the Knee Society Score at postoperative 2 years. Postoperative status of articular cartilage was assessed by arthroscopy according to the International Cartilage Repair Society (ICRS) grade at the time of plate removal. RESULTS: The Knee Society Score objective score and function score were improved at postoperative 2 years compared with preoperative value in both groups, but no significant difference was found between the 2 groups. According to the ICRS overall repair grade, cartilage status was rated as normal or nearly normal (ICRS overall score ≥8) in 41% of the BMS group and 90% of the OAT group. The results suggested that cartilage repair in OAT was significantly better than that in BMS (P = .0015). Furthermore, the BMS group revealed that repair with normal or nearly normal was observed in all less than 4 cm2 of lesion size, whereas the OAT group exhibited that repair with normal or nearly normal was independent of lesion size. CONCLUSIONS: This study suggested that OAT is superior to BMS as a concomitant procedure with opening-wedge valgus HTO for spontaneous osteonecrosis of the MFC in the success of cartilage repair. However, clinical outcomes were not significantly different between these 2 procedures. When treating the lesion larger than 4 cm2 by joint-preserving surgery, OAT mosaicplasty is recommended as a concomitant procedure with HTO. LEVEL OF EVIDENCE: Level III, therapeutic case-control study.

Combined CT-based and image-free navigation systems in TKA reduces postoperative outliers of rotational alignment of the tibial component.

INTRODUCTION: Rotational malpositioning of the tibial component can lead to poor functional outcome in TKA. Although various surgical techniques have been proposed, precise rotational placement of the tibial component was difficult to accomplish even with the use of a navigation system. The purpose of this study is to assess whether combined CT-based and image-free navigation systems replicate accurately the rotational alignment of tibial component that was preoperatively planned on CT, compared with the conventional method. MATERIALS AND METHODS: We compared the number of outliers for rotational alignment of the tibial component using combined CT-based and image-free navigation systems (navigated group) with those of conventional method (conventional group). Seventy-two TKAs were performed between May 2012 and December 2014. In the navigated group, the anteroposterior axis was prepared using CT-based navigation system and the tibial component was positioned under control of the navigation. In the conventional group, the tibial component was placed with reference to the Akagi line that was determined visually. Fisher's exact probability test was performed to evaluate the results. RESULTS: There was a significant difference between the two groups with regard to the number of outliers: 3 outliers in the navigated group compared with 12 outliers in the conventional group (P < 0.01). CONCLUSIONS: We concluded that combined CT-based and image-free navigation systems decreased the number of rotational outliers of tibial component, and was helpful for the replication of the accurate rotational alignment of the tibial component that was preoperatively planned.

Factors affecting cartilage repair after medial opening-wedge high tibial osteotomy.

PURPOSE: This study documented the healing potential of degenerated articular cartilage after opening-wedge valgus high tibial osteotomy (HTO) in patients with osteoarthritis of the knee. It was hypothesized that regeneration of articular cartilage is affected by several factors, including preoperative cartilage degeneration grade, difference between the medial femoral condyle (MFC) and the medial tibial condyle (MTC), and postoperative knee alignment. METHODS: Medial opening-wedge valgus HTO was performed in 131 knees of 100 patients (mean age 66 ± 7.7 years). Initial arthroscopy was performed at the time of HTO, and a second-look arthroscopy was performed at the time of plate removal (20.8 ± 6.5 months after HTO). Status of articular cartilage was assessed according to the ICRS grade. Cartilage regeneration was also evaluated by the presence of newly formed cartilaginous tissue. All subjects were followed up postoperatively at 2 years for assessment of clinical and radiographic outcomes. RESULTS: The number of subjects in ICRS grade 1/2/3/4 was significantly altered from 0/11/53/67 preoperatively to 14/21/56/40 postoperatively in the MFC (P < 0.05) and 0/12/62/57 preoperatively to 9/24/64/34 postoperatively in the MTC (P < 0.05). Newly formed cartilaginous tissue was found in 71 % of MFCs and 51 % of MTCs. Incidence of cartilage regeneration was significantly higher in lower BMI cases, MFC, preoperatively advanced ICRS grade and overcorrected knees. Age, gender and clinical outcomes did not affect cartilage regeneration. CONCLUSION: Cartilage regeneration in degenerated articular cartilage is induced after opening-wedge valgus HTO, which is affected by BMI, the difference between the MFC and MTC, preoperative cartilage degeneration grade, and postoperative limb alignment. Therefore, patient selection by BMI rather than age, and surgical techniques maintaining valgus knee alignment should be considered for cartilage regeneration. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

The use of factor Xa inhibitors following opening-wedge high tibial osteotomy for venous thromboembolism prophylaxis.

PURPOSE: This study aimed to investigate the incidence of venous thromboembolism (VTE) after medial opening-wedge high tibial osteotomy (OWHTO) and evaluate the efficacy and safety of edoxaban for the prevention of VTE in patients undergoing OWHTO. METHODS: A total of 139 patients with osteoarthritis or osteonecrosis undergoing OWHTO were enrolled in this prospective, randomized study. Four patients were excluded because of preoperatively diagnosed VTE, and 135 patients were divided into two groups-an edoxaban group and a non-edoxaban group-and underwent computed tomography venography on day 7 to check for postoperative VTE. Blood samples were taken on the day before OWHTO and on postoperative days 1, 3, 7, and 14. RESULTS: Treatment with edoxaban reduced the incidence of VTE after OWHTO; however, there was no statistically significant difference between the two groups. No major bleeding was noted in the edoxaban group. There were significant differences in the D-dimer level, prothrombin time, fibrinogen level, and thrombin antithrombin complex levels between the groups. CONCLUSIONS: Edoxaban is an oral, once-daily, selective, direct factor Xa inhibitor that is safe and easy to handle. It may offer a new option for preventing VTE after OWHTO. LEVEL OF EVIDENCE: I.

Total knee arthroplasty improves both knee function and disease activity in patients with rheumatoid arthritis.

OBJECTIVE: This study evaluated the effect of TKA with capsulosynovectomy on disease activity and knee function in patients with RA. METHODS: Seventy-six RA patients who underwent primary TKA with more than two years of follow-up were retrospectively reviewed to assess postoperative knee function and disease activity. RESULTS: Postoperative knee function was significantly improved in all clinical scores, and maintained up to 24 months after surgery. RA disease activity was significantly decreased in DAS28-CRP, CDAI, and serum CRP level, and maintained up to 24 months after surgery. Postoperative knee function was negatively correlated with RA disease activity. CONCLUSIONS: TKA improves both knee function and disease activity in patients with rheumatoid arthritis.

Comparative Study of Opening-Wedge High Tibial Osteotomy With and Without a Combined Computed Tomography-Based and Image-Free Navigation System.

PURPOSE: To assess whether a combined computed tomography (CT)-based and image-free navigation system results in better coronal and sagittal alignment than the conventional method for performing opening-wedge high tibial osteotomy (OWHTO) and whether CT-based navigation results in acquisition of an accurate osteotomy plane. METHODS: Sixty-two consecutive knees were randomly divided into navigated and conventional groups. The intraoperative correction angle was determined by the change in hip-knee-ankle angle in the navigated group and by the predicted medial opening width in the conventional group. Outliers of femorotibial angle (FTA) and tibial posterior slope (TPS) were defined as angles of >175° or <165° and angles of >2.5° or <-2.5°, respectively. Radiographic and clinical data were compared between the 2 groups at 2 years postoperatively. RESULTS: Mean postoperative FTAs were 168.5° in the navigated group and 168.1° in the conventional group. Mean change in TPS of -0.2° in the navigated group was significantly lower than that of 1.6° in the conventional group (P = .005). On postoperative CT, mean angle between the tibial plateau and osteotomy planes in the sagittal plane showed a significantly higher anterior opening of 12° in the conventional than in the navigated group (P < .001). There was a significantly greater proportion of TPS outliers in the conventional (51.6%) than in the navigated group (12.9%) (P = .001), and a significantly greater proportion within the normal range in both planes in the navigated (74.2%) than in the conventional group (48.4%) (P = .037). CONCLUSIONS: Combined CT-based and image-free navigation in OWHTO better preserves the original TPS and more frequently restores normal coronal and sagittal plane knee joint alignment. CT-based navigation also enabled acquisition of our target osteotomy plane in the sagittal plan. The navigation system in OWHTO was helpful for simultaneous control of the alignment in 2 planes. LEVEL OF EVIDENCE: Level II, lesser-quality prospective randomized trial.

Femoral shaft bowing in the coronal and sagittal planes on reconstructed computed tomography in women with medial compartment knee osteoarthritis: a comparison with radiograph and its predictive factors.

PURPOSE: To show the differences in lateral and anterior femoral shaft bowing (FSB) between radiographic and computed tomography (CT) images and to assess whether FSB is associated with various predictive factors in women with knee osteoarthritis (OA) using CT images. METHODS: We enrolled 135 Japanese women with medial compartment knee OA. Lateral and anterior FSB were measured by radiography and reconstructed CT. Age, body mass index (BMI), femorotibial angle (FTA), femoral length, and lumbar spine and femoral neck bone mineral density (BMD) were set as predictive factors for progression of knee OA. We compared predictive factors in the lateral FSB group having lateral angulations of >5° with those in the nonbowing group and compared predictive factors in the anterior FSB group having anterior angulations of >11° with those in the nonbowing group. Binomial logistic regression modeling was applied to determine independent predictors of both FSB. RESULTS: There were significant differences in both FSB between the radiographic and reconstructed CT images (P = 0.005 and P = 0.047, respectively). In binomial logistic regression analyses for lateral FSB on CT, age, BMI, and lumbar spine BMD were significant predictors, with odds ratios of 1.16, 1.22, and 0.03, respectively; for anterior FSB on CT, age was a significant predictor, with an odds ratio of 1.06. CONCLUSIONS: It is preferable to measure both FSB on reconstructed CT when planning reconstructive knee surgeries. Age, BMI, and lumbar spine BMD were predictors of lateral FSB progression, and age was a predictor of anterior FSB progression. Level of evidence Level III.

Is the surgical epicondylar axis the center of rotation in the osteoarthritic knee?

The relationship between the surgical epicondylar axis (SEA) and the rotational axis of the distal femur remains unclear. We investigated the relationship between the SEA and the distal femur and whether the SEA can be used as the rotational axis of the knee. Angular and linear measurements of 70 femora at 0°, 30°, 60°, 90°, and 120° of flexion were recorded. Results showed that the SEA was a logical and appropriate parameter as a principal axis for knee flexion at least between 0° and 60° of flexion. The study has important implications for the design and positioning of femoral components in total knee arthroplasty.

The surgical epicondylar axis is a consistent reference of the distal femur in the coronal and axial planes.

PURPOSE: Various rotational landmarks including the surgical epicondylar axis (SEA) are used for preoperative planning and intra-operative reference of total knee arthroplasty (TKA) in the axial plane. The aim of the study was to elucidate the relationships between the SEA and other femoral anatomical landmarks, including the mechanical axis, distal and posterior knee joints, the trochlear groove, and the anterior femoral condyle, in both the coronal and axial planes. METHODS: Angular and linear measurements were taken of sixty femora using Orthomap3D, which has a tool to analyse computed tomography image data that makes it possible to measure three-dimensional distances and angles precisely. The inter- and intra-observer reliabilities of these measurements were evaluated. Comparisons were made according to height, weight, body mass index, and gender. RESULTS: The angle between the mechanical axis and the SEA was 90.2° (95% CI 90.0°-90.4°). There was a significant correlation for each linear measurement between the SEA and the distal/posterior knee joint line and for each linear measurement between the SEA and the anterior medial/lateral femoral condyle. A significant difference was observed between genders in the linear measurements. Significant correlations were found between height and weight and linear parameters. CONCLUSION: Knowledge of the relationships between the SEA and other femoral anatomical landmarks is useful in preoperative planning, intra-operative landmark, and postoperative assessment of TKA. The SEA is a consistent parameter of femoral alignment in the coronal plane and a stable reference for femoral rotation in the axial plane. LEVEL OF EVIDENCE: III.

Opening Wedge High Tibial Osteotomy Using Combined Computed Tomography-Based and Image-Free Navigation System.

For opening wedge high tibial osteotomy (OWHTO), it is recommended that the osteotomy line is parallel to the medial tibial posterior slope (TPS) in the sagittal view and that the alignments are simultaneously controlled in the coronal and sagittal views. Here combined computed tomography (CT)-based and image-free navigation systems were used for intraoperative reference during OWHTO. Using the CT-based navigation, 2 entry points for insertion of Kirschner wires were preoperatively set up and an accurate osteotomy plane was intraoperatively duplicated. Preoperative planning anticipated a femorotibial angle of 170°, representing a weight-bearing ratio of 62.5%, on the whole-leg radiograph. The original TPS in the sagittal view was aimed to be preserved postoperatively. The hip-knee-ankle (HKA) correction angle was preoperatively measured on the whole-leg radiograph, and the HKA angle and flexion angle were intraoperatively monitored in real time using the image-free navigation. We have introduced an operative technique for OWHTO using CT-based and image-free navigation systems. We expect that this method, with the osteotomy plane parallel to the tibial plateau plane in the sagittal view and simultaneous control of coronal and sagittal alignments, will enable actuation of accurate alignment in the 2 planes and lead to improvements in patient activity in future.

Coronal subluxation of the proximal tibia relative to the distal femur after opening wedge high tibial osteotomy.

BACKGROUND: The coronal subluxation of the proximal tibia relative to the distal femur is a common radiological finding in patients with knee osteoarthritis. The purpose was to evaluate whether the coronal subluxation was corrected after opening wedge high tibial osteotomy (OWHTO), and whether this subluxation was one cause of inconsistency between the actual and predicted alignments (correction loss). METHODS: Fifty-one patients (55 knees) were treated with OWHTO. The change of location between the intersection points of the femoral and tibial axes on the tibial plateau (subluxation-C), the change of location between the lines through the most lateral points of the lateral femoral and tibial condyles (subluxation-L), and joint space angle (JSA) were compared in standing knee radiographs before and one year after OWHTO. The subluxation-C and subluxation-L were converted to a percentage of the tibial plateau width. RESULTS: The mean subluxation-C of 6.5% before OWHTO significantly increased to a mean subluxation-C of 7.3% one year after OWHTO. The mean subluxation-L of 6.3% and JSA of 4.5° before OWHTO significantly decreased to a subluxation-L of 1.8% and JSA of 3.3° one year after OWHTO. The change in subluxation-L correlated with the change in femorotibial angle and correction loss (r=0.634, P<0.001 and r=0.463, P<0.001, respectively). CONCLUSION: The proximal tibia shifted medially relative to the distal femur after OWHTO. This medial shift correlated with the correction loss. The coronal subluxation might be one cause of correction loss.

Radiographic and computed tomographic evaluation of bone union after medial opening wedge high tibial osteotomy with filling gap.

BACKGROUND: We evaluated bone union and remodelling in patients undergoing opening-wedge high tibial osteotomy (OWHTO) with bone gaps filled with beta-tricalcium phosphate. We examined the effectiveness of radiography and computed tomography (CT) for the evaluation of bone union and remodelling, and investigated whether lateral hinge fractures affected bone union. METHODS: Sixty-six cases underwent OWHTO with a combination of a TomoFix plate and a bone substitute. Bone union and remodelling were assessed using the rating system for OWHTO at three and six months, postoperatively. RESULTS: Radiographic evaluation showed that bone union of the lateral hinge was 85% and 100% at three and six months, respectively. Based on CT evaluation, bone union of the lateral hinge and the flange was achieved in all cases at six months, and the bone union of the posterior cortex reached Zone 3 in 83% at six months. Based on radiographic evaluation, bone remodelling phases of bone substitute had progressed in each zone in six months compared with three months. Radiographic and CT analyses identified a Takeuchi type I hinge fracture in fourteen (21.2%) and five (7.6%) knees at two weeks postoperatively, respectively. There were no differences in bone union with and without the lateral hinge fracture. CONCLUSIONS: The use of CT enabled us to evaluate the bone union of the flange and the extent of the bone union of the posterior cortex. Plain radiographs are useful to evaluate bone union of the lateral hinge similar to CT analysis. The presence of a Takeuchi type I hinge fracture did not affect bone union.

Changes in synovial fluid biomarkers and clinical efficacy of intra-articular injections of hyaluronic acid for patients with knee osteoarthritis.

BACKGROUND: The changes in synovial fluid biomarkers after intra-articular injection of hyarulonic acid (IA HA) remain controversial. We investigate the changes in the properties of synovial fluid (SF) and clinical symptoms before the first and fifth IA HA. METHODS: A total of 73 patients (73 knees) with symptomatic knee osteoarthritis were treated with five weekly intra-articular injections of HA and 55 patients (55 knees) were analyzed. The SF total volume, viscosity, and levels of HA, chondroitin 4-sulfate (C4S), chondroitin 6-sulfate (C6S), keratin sulfate, and interleukin (IL)-6 were measured before the first and fifth injections. Clinical evaluations were performed using the American Knee Society score for physician-based outcome measurements and Knee injury and Osteoarthritis Outcome Score for patient-based outcome measurements before the first and fifth injections. RESULTS: The SF viscosity and levels of HA were significantly increased, and the total SF volume and levels of chondroitin 4-sulfate, chondroitin 6-sulfate, and interleukin-6 were significantly decreased. The physician-based and patient-based outcome scores were improved. CONCLUSIONS: Our findings speculate that HA injections significantly modulate levels of intra articular biomarkers which may indicate beneficial effect for articular cartilage and synovium membrane.