Masato Aratake

Medial Opening Wedge High Tibial Osteotomy With Early Full Weight Bearing

PURPOSE We performed clinical and radiographic evaluation of patients with medial compartment osteoarthritis of the knee who had undergone treatment with opening wedge high tibial osteotomy (OWHTO) followed by early full weight bearing. OWHTO procedures were performed by use of TomoFix (Synthes, Bettlach, Switzerland) and bone substitute materials. METHODS OWHTO was performed in 57 knees in 52 patients with a mean age of 69 years (range, 54 to 82 years) at the time of operation. The diagnosis was primary osteoarthritis in 34 knees in 29 patients and osteonecrosis in a further 23 knees in 23 patients. We established an early weight-bearing exercise program during which these patients were permitted partial weight-bearing exercise 1 week after their osteotomy procedure. All patients performed full weight-bearing exercises at 2 weeks after surgery. The mean follow-up period was 40 months (range, 24 to 62 months). RESULTS The American Knee Society Score and Function Score showed significant improvement from 50.9 +/- 12.3 to 91.7 +/- 6.9 points and 59.3 +/- 13.1 to 94.1 +/- 8.8 points, respectively. Before surgery, the mean femorotibial angle during standing was 181.3 degrees +/- 2.4 degrees (1.3 degrees anatomic varus), but it measured 169.6 degrees +/- 2.3 degrees (10.4 degrees valgus) at the time of follow-up. There were no instances of nonunion or implant failure in any of our patients. CONCLUSIONS We have shown that an early weight-bearing exercise program enables full weight bearing at 2 weeks after OWHTO with TomoFix and artificial bone wedges. Overall, this combination was a highly successful course of treatment for correcting knee malalignment in patients with medial compartment osteoarthritis. LEVEL OF EVIDENCE Level IV, therapeutic case series.

A mid term comparison of open wedge high tibial osteotomy vs unicompartmental knee arthroplasty for medial compartment osteoarthritis of the knee.

BackgroundThe choice of surgical treatments for unicompartmental osteoarthritis (OA) of the knee is still somewhat controversial. Midterm results from cases treated using unicompartmental knee arthroplasty (UKA) or open wedge high tibial osteotomy (OWHTO) were evaluated retrospectively.MethodsTwenty-seven knees of 24 patients with varus deformities underwent OWHTO and 30 knees of 18 patients underwent UKA surgeries for the treatment of medial compartmental osteoarthritis (OA). The KSS score, FTA, range of motion and complications were evaluated before and after surgery.ResultsThe preoperative mean KSS scores were 49 points in the OWHTO group and 62 in the UKA group which improved postoperatively to 89 (excellent; 19 knees, good; 8 knees), and 88 (excellent; 25, good; 4, fair; 1), respectively. There was no significant difference between the OWHTO and UKA scores. Seventeen patients in the OWHTO group could sit comfortably in the formal Japanese style after surgery. The preoperative mean FTA values for the OWHTO and UKA groups were 182 degrees and 184, and at follow-up measured 169 and 170, respectively. In the UKA group, the femoral component and the polyethylene insertion in one patient was exchanged at 5 years post-surgery and revision TKAs were performed in 2 cases. In the OWHTO group, one tibial plateau fracture and one subcutaneous tissue infection were noted.ConclusionsTreatment options should be carefully considered for each OA patient in accordance with their activity levels, grade of advanced OA, age, and range of motion of the knee. OWHTO shows an improved indication for active patients with a good range of motion of the knee.

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.

Clinical evaluation of the effect of attenuation correction technique on18F-fluoride PET images

Objective: The purpose of this study is to evaluate effect of attenuation correction technique on18F-fluoride positron emission tomography (PET).Methods: We performed PET scans after the injection of 185 MBq18F-fluoride on 32 patients from October 20th, 2004 to April 13th, 2005. We calculated bone-to-muscle ratios for the images with and without attenuation correction. We placed regions of interest (ROIs) on normal bone accumulation in 22 patients. The exclusion criteria were bone metastasis, Pagets disease, and rheumatoid arthritis. Several regions were chosen for ROI placement: skull, cervical vertebra, mandible, scapula, thoracic vertebra, rib, humerus, lumbar vertebra, radius, ulna, pelvis, femoral head, femoral shaft, tibia, and fibula. The count ratios of normal bones to gluteus muscle were calculated as bone-to-muscle ratios. The count ratios of abnormal skeletal lesions to gluteus muscles were calculated as bone-to-muscle ratios, while the count ratios of abnormal skeletal lesions to normal bones were calculated as bone-to-bone ratios.Results: PET images without attenuation correction showed significantly higher mean bone-to-muscle ratios than those with attenuation correction (p<0.05) for all normal bones except the femoral head and lumbar vertebrae. For abnormal bones, bone-to-muscle ratios without attenuation correction were significantly higher than those with attenuation correction (p<0.005). The same statistical significance was found for bone-to-bone ratios (p<0.005).Conclusions: The attenuation correction technique is not necessary to conduct the visual interpretation of18F-fluoride PET images. The bone-to-muscle ratio analysis without attenuation correction may be of use to differentiate malignant from benign disease processes.

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.

Mid- term results of stryker® scorpio plus mobile bearing total knee arthroplasty

BackgroundThe mobile bearing knee system was introduced to lessen contact stress on the articular bearing surface and reduce polyethylene wear. The purpose of the current study was to investigate the mid-term results of patients undergoing total knee arthroplasties (TKAs) using Scorpio Plus Mobile Bearing Knee System (Stryker, Mahwah, NJ), and compare the outcomes between patients with osteoarthritis and osteonecrosis (OA·ON group) and patients with rheumatoid arthritis (RA group).MethodsEight males and 58 females were followed up for a period of 4.4- 7.6 years from June 1, 2003 to December 31, 2005. There were 53 knees with osteoarthritis, 17 knees with rheumatoid arthritis, and 6 knees with osteonecrosis. Clinical and radiographic follow- up was done using The Japanese Orthopedic Association knee rating score (JOA score) and Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System.ResultsWith regard to the JOA score, there was significant improvement in both groups. The postoperative range of motion was between 0.8°and 116.8° in OA·ON group, and between 0.0° and 113.7° in RA group. There were no significant differences with the radiographic evaluation between two groups. Spontaneous dislocation of a polyethylene insert occurred in one patient, and deep infection was occurred in one patient.ConclusionThere was significant improvement with regard to the clinical and radiographic results of patients undergoing TKAs using the model. The risk of polyethylene insert dislocation related to the mobile bearing TKA is a cause for concern.

Reproducibility of condylar twist angle measurement using computed tomography and axial radiography of the distal femur

INTRODUCTION It is essential to understand rotational alignment of the distal femur when performing total knee arthroplasty (TKA). Several rotational landmarks including condylar twist angle (CTA) are used for preoperative planning and during TKA. Axial radiography of the distal femur is used for measuring the CTA, and assessing rotational alignment in TKA. The aim of this study was to investigate the reliability and the reproducibility of the CTA using two different methods and evaluate if CTA differed between varus and valgus knees and between normal and osteoarthritic knees. MATERIALS AND METHODS CTA were obtained from 144 knees (77 patients) having total knee or hip arthroplasty using computed tomography (CT) and axial radiography. Subjects were divided into five groups based on femorotibial angle (FTA) and into four groups based on the severity of knee osteoarthritis. The intra-observer and inter-observer reliabilities of these methods and inter-method differences were evaluated. RESULTS The mean CTA was 7.02° with axial radiography, and 6.87° with CT images. There were no significant differences among the five FTA groups and among the four osteoarthritis groups. In total, intra-/inter-observer, and inter-method intraclass correlation coefficients were substantial or almost perfect in the scoring system of Landis et al. However, discrepancies ≥ 2° between the two methods were observed in more than 20% of knees. CONCLUSION The CTA should be reassessed by more than two observers or two methods for precise preoperative TKA planning in cases where it is difficult to identify the bony landmarks for CTA measurements. LEVEL OF EVIDENCE Level III.

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.