Yoshihiro Kusayama

Five- to ten-year outcome following medial opening-wedge high tibial osteotomy with rigid plate fixation in combination with an artificial bone substitute

Between 2003 and 2007, 99 knees in 77 patients underwent opening wedge high tibial osteotomy. We evaluated the effect of initial stable fixation combined with an artificial bone substitute on the mid- to long-term outcome after medial opening-wedge high tibial osteotomy (HTO) for medial compartmental osteoarthritis or spontaneous osteonecrosis of the knee in 78 knees in 64 patients available for review at a minimum of five years (mean age 68 years; 49 to 82). The mean follow-up was 6.5 years (5 to 10). The mean Knee Society knee score and function score improved from 49.6 (SD 11.4, 26 to 72) and 56.6 (SD 15.6, 5 to 100) before surgery to 88.1 (SD 12.5, 14 to 100) and 89.4 (SD 15.6, 5 to 100) at final follow-up (p < 0.001) respectively. There were no significant differences between patients aged ≥ 70 and < 70 years. The mean standing femorotibial angle was corrected significantly from 181.7° (SD 2.7°, 175° to 185°) pre-operatively to 169.7° (SD 2.4°, 164° to 175°) at one years follow-up (p < 0.001) and 169.6° (SD 3.0°, 157° to 179°) at the final follow-up (p = 0.69 vs one year). Opening-wedge HTO using a stable plate fixation system combined with a bone substitute is a reliable procedure that provides excellent results. Although this treatment might seem challenging for older patients, our results strongly suggest that the results are equally good.

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 extent of degeneration of cruciate ligament is associated with chondrogenic differentiation in patients with osteoarthritis of the knee

OBJECTIVE Degeneration in cruciate ligaments results from abnormal biomechanical stress and the aging process. Such degeneration is a common outcome in patients with osteoarthritis (OA) of the knee and contributes to the progression of OA. However, to date, there are no specific markers that can predict the extent of ligament degeneration. We hypothesized that the extent of degeneration has correlations to increased chondrogenic potential. METHODS Twenty anterior cruciate ligaments (ACLs) and 30 posterior cruciate ligaments (PCLs) from 30 knees of 28 adult patients with OA at the time of total knee arthroplasty were used for the study. Degeneration was histologically assessed using a grading system. Expressions of Scleraxis (as a ligament cell marker) and Sry-type HMG box 9 (SOX9) (as a chondrogenic marker) were immunohistochemically assessed in each grade. RESULTS We found the opposite expression pattern between Scleraxis and SOX9 according to the grade. The percentage of Scleraxis-positive cells decreased significantly by grade (60.9±23.7 in grade 1, 39.7±30.5 in grade 2, and 13.9±27.1 in grade 3, P<0.0001). In contrast, the percentage of SOX9-positive cells increased significantly by grade (2.5±4.9 in grade 1, 17.5±13.4 in grade 2, and 50.9±27.1 in grade 3, P<0.0001). Furthermore, co-localized expression of both Scleraxis and SOX9 was demonstrated in chondrocyte-like cells. CONCLUSIONS This study indicates that chondrogenic differentiation is associated with the progression of degeneration in human ligaments. Our results suggest that the expression of SOX9 as a chondrogenic marker could be an indicator for the extent of degeneration in human ligaments. It remains to be elucidated whether suppression of chondrogenic differentiation can prevent progression of the degenerative process of cruciate ligaments in patients with OA.

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

Abstract 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.

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

BackgroundThe 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.MethodsA 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.ResultsThe 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.ConclusionsOur findings speculate that HA injections significantly modulate levels of intra articular biomarkers which may indicate beneficial effect for articular cartilage and synovium membrane.

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

AbstractPurpose 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.MethodsA 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.ResultsTreatment 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.ConclusionsEdoxaban 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 evidenceI.

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.

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

IntroductionRotational 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 methodsWe 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.ResultsThere 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).ConclusionsWe 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.

Edoxaban is effective in reducing the incidence of asymptomatic phlebographic events following closed-wedge high tibial osteotomy

INTRODUCTION The purpose of this study was twofold: to investigate whether edoxaban significantly decreases the rate of venous thromboembolism (VTE) following closed-wedge high tibial osteotomy (CWHTO), in terms of phlebographic event, and to determine whether edoxaban is safe or increases the rate of hemorrhagic complications. We hypothesized that edoxaban would decrease the incidence of VTE and would not increase the rate of hemorrhagic complications. MATERIALS AND METHODS We randomly enrolled 60 patients undergoing CWHTO. The patients were divided into two groups: one group receiving edoxaban (15mg in 5 patients, 30mg in 23 patients) and a non-edoxaban group. All patients underwent computed tomography venography on day 7to diagnose postoperative VTE. Blood samples were obtained on the day before CWHTO and on postoperative days 1, 3, 7 and 14. The incidence of VTE and hemorrhagic events in both groups was compared using unpaired Student t-test or chi-square test. RESULTS The incidence of VTE was significantly greater in the non-edoxaban group (31.3% versus 7.1%; P=0.02). The incidence of deep vein thrombosis (DVT) was also significantly greater in the non-edoxaban group (28.1% versus 3.6%; P=0.01). A single patient from the edoxaban group experienced major bleeding. On days 3 and 7, D-dimer levels were significantly lower in the edoxaban group (P=0.03 and 0.003, respectively). On days 3, 7 and 14, activated partial thromboplastin time was significantly greater in the edoxaban group (P=0.02, 0.01 and 0.006, respectively). CONCLUSION Patients undergoing CWHTO are at risk of postoperative VTE. Edoxaban helps prevent asymptomatic phlebographic VTE and DVT following CWHTO; however, the risk of major bleeding must be considered. LEVEL OF EVIDENCE II.

Influence of coronal bowing on the lower alignment and the positioning of component in navigation and conventional total knee arthroplasty

BACKGROUND Coronal alignment is an important factor for the function and longevity of total knee arthroplasty (TKA). Coronal bowing of the lower extremity is common among Asians and it may pose a risk for malalignment of the lower leg and malposition of component. HYPOTHESIS We hypothesized that coronal bowing itself has a risk for malalignment of the lower leg and malposition of femoral/tibial components and that navigation TKA is beneficial for patients with coronal bowing. We investigated the incidence of femoral/tibial bowing in patients treated with TKA and compared the radiographic parameters between the navigation group and the conventional group. Additionally, the influence of coronal bowing on these radiographic parameters was investigated. MATERIALS AND METHODS We enrolled 35 patients with knee osteoarthritis and 70 bilateral simultaneous TKAs. The patients underwent TKA with the use of a computer tomography-free navigation in one knee and conventional TKA in the contralateral knee. Preoperative coronal bowing were measured, and the subjects were divided into 2 subgroups, i.e. the bowing group and the non-bowing group. Lateral bowing was expressed as plus (+) and medial bowing was expressed as minus (-). Various radiographic parameters, including coronal bowing, lower leg alignment, component position, and outliers were compared between the navigation group and the conventional group. RESULTS Femoral bowing varied from -7.4° to 10.9° with an average of 3.0°. Tibial bowing varied from -4.1° to 4.6° with an average of 0.4°. The femoral component was placed more properly in the navigation group. Number of outlier regarding to the coronal femoral component angle to the femoral mechanical axis was 14 cases (37.8%) in the bowing group and 6 cases (18.2%) in the non-bowing group (P=0.04). DISCUSSION In conclusion, coronal femoral bowing has an important effect on femoral bone cut in TKA. The navigated TKA was more consistent than conventional TKA in aiding proper alignments of femoral component. LEVEL OF EVIDENCE Level II, comparative prospective study.