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.

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.

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.

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

BACKGROUND: The 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). METHODS: Eight 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. RESULTS: With 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. CONCLUSION: There 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.

Case of juxta-articular osteoid osteoma of calcaneus mimicking arthritis.

Juxta-articular osteoid osteoma is a rare disorder that is difficult to correctly diagnose at an early stage. We report a case of osteoid osteoma in the calcaneus that arose near to the talocalcaneal joint. An 18-year-old female presented with symptoms of joint swelling and effusion similar to those of monoarthritis. Conservative treatment proved ineffective in achieving pain relief, and she underwent surgery 6 months later. The lesion was diagnosed by histologic examination, and it resolved after resection of the tumor.

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

BACKGROUND: The 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. METHODS: Twenty-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. RESULTS: The 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. CONCLUSIONS: Treatment 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.

Opening wedge high tibial osteotomy affects both the lateral patellar tilt and patellar height.

In the current study, we evaluated changes in the patellofemoral joint indices in 49 knees from 39 patients (11 men and 28 women with a median age of 64 years; range 53-79) who had undergone an opening wedge high tibial osteotomy (OWHTO). Osteoarthritis had been diagnosed in 39 knees and osteonecrosis in the other 10 knees in this patient cohort. Radiographs showing anteroposterior and true lateral views of the knee joints while standing, and also skyline views while standing with a 30 degrees flexion, were taken both pre- and postoperatively. Radiographic assessments were then performed using the following five parameters: femorotibial angle (FTA), modified Blackburne-Peel ratio (mBP), tibial slope (TS), lateral patellar tilt (LPT), and lateral patellar shift (LPS). The average LPT decreased significantly from 7.4 degrees + or - 3.7 degrees to 5.2 degrees + or - 3.6 degrees (P < 0.01). Patients treated with a greater than 15 degrees correction showed a significantly bigger change in their LPT than those with corrections of 15 degrees or less. No statistical differences were found between the preoperative (10.2 + or - 4.5%) and postoperative (10.2 + or - 4.7%) LPS measurements. Changes in the radiographic parameters were also observed in the patellofemoral joint after OWHTO. It is unclear to what extent the postoperative patellar shift and tilt affects the long-term clinical outcomes but our current results suggest that OWHTO negatively affects the congruency of the patellofemoral joint and should not exceed a correction of 15 degrees .

A predictive factor for acquiring an ideal lower limb realignment after opening-wedge high tibial osteotomy.

Obtaining a correct postoperative limb alignment is an important factor in achieving a successful clinical outcome after an opening-wedge high tibial osteotomy (OWHTO). To better predict some of the aspects that impact upon the clinical outcomes following this procedure, including postoperative correction loss and over correction, we examined the changes in the frontal plane of the lower limb in a cohort of patients who had undergone OWHTO using radiography. Forty-two knees from 33 patients (23 cases of osteoarthritis and 10 of osteonecrosis) underwent a valgus realignment OWHTO procedure and were radiographically assessed for changes that occurred pre- and post-surgery. The mean femorotibial angle (FTA) was found to be 182.1 +/- 2.0 degrees (12 +/- 2.0 anatomical varus angulation) preoperatively and 169.6 +/- 2.4 degrees (10.4 +/- 2.4 anatomical valgus angulation) postoperatively. These measurements thus revealed significant changes in the weight bearing line ratio (WBL), femoral axis angle (FA), tibial axis angle (TA), tibia plateau angle (TP), tibia vara angle (TV) and talar tilt angle (TT) following OWHTO. In contrast, no significant change was found in the weight bearing line angle (WBLA) after these treatments. To assess the relationship between the correction angle and these indexes, 42 knees were divided into the following three groups according to the postoperative FTA; a normal correction group (168 degrees < or = FTA < or = 172 degrees ), an over-correction group (FTA < 168 degrees ), and an under-correction group (FTA > 172 degrees ). There were significant differences in the delta angle [DA; calculated as (pre FTA - post FTA) - (pre TV - post TV)] among each group of patients. Our results thus indicate a negative correlation between the DA and preoperative TA (R(2) = 0.148, p < 0.05). Hence, given that the correction errors in our patients appear to negatively correlate with the preoperative TA, postoperative malalignments are likely to be predictable prior to surgery.

Clinical results and radiographical evaluation of opening wedge high tibial osteotomy for spontaneous osteonecrosis of the knee.

We evaluated the clinical outcomes, in terms of early weight bearing, of using opening wedge high tibial osteotomy (OWHTO) to treat spontaneous osteonecrosis of the medial femoral condyle of the knee (SONK) using TomoFix and artificial bone substitute. Damaged cartilage tissue was removed and drilling of the necrotic area followed by OWHTO was performed in 30 knees from 30 patients with an average age of 71 years (range 58-82) at the time of operation. Patients were allowed to undertake partial weight-bearing exercises 1 week after the osteotomy procedure, with all patients performing full weight-bearing exercise at 2 weeks post-surgery. The mean follow-up period was 40 months (range 24-62). All of the SONK patients could walk with a full weight-bearing load, using only a T-cane, at 2 weeks after undergoing OWHTO. Clinical assays, including the mean American Knee Society Score and Function Score, showed significant improvements from 51 to 93 points, and 58 to 93 points, respectively. Prior to surgery, the average femoro-tibial angle (FTA) during standing was 181 (1 degree anatomical varus) and had significantly changed to 170 (10 degrees valgus) at the time of follow-up. There were no cases of non-union, or implant failure in any of our patients. In addition, none of the patients could sit in the Japanese style prior to surgery, but 21 of 30 patients (70%) could do so after treatment. Arthroscopic findings could be observed in 24 out of 30 cases at implant removal. Necrotic area in each case was covered with fibrous cartilage-like tissue completely. Drilling of the necrotic area followed by OWHTO with TomoFix and artificial bone substitute is an effective treatment for SONK as it results in pain alleviation and regeneration of the fibrous cartilage tissue over the necrotic legion. In addition, an early weight-bearing exercise program is possible after this procedure and full weight-bearing can be achieved at two weeks after surgery.

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.

Evaluation of lesion in a spontaneous osteonecrosis of the knee using 18F-fluoride positron emission tomography.

Positron-emission tomography (PET) imaging has several advantages over conventional scintigraphy, including a high spatial resolution and the ability to quantify disease progression. Recently, (18)F-fluoride PET has been applied to the evaluation of malignant tumors and musculoskeletal disorders. In our current study, spontaneous osteonecrosis of the knee (SONK) was visualized using this technique. We determined whether PET images can reveal SONK lesions, whether there were significant differences in the maximum standardized uptake value (SUVmax) among each of the SONK stages, and finally if there was any correlation between the maximum SUVmax value and size of the SONK lesion measured both by radiography and MRI. Fourteen knees from 13 patients diagnosed with SONK were imaged using a PET scanner. In all cases, PET showed an accumulation of 18F-fluoride in the medial condyle. The SUVmax ranged from 8.6 to 23.7 with an average of 15.1 +/- 3.7 and was measured at different disease stages with an average of 12.4 +/- 5.9 in Stage 2 (n = 5), 16.3 +/- 1.4 in Stage 3 (n = 4), and 16.8 +/- 4.3 (n = 5) in Stage 4 lesions. There were no significant differences in these measurements between the SONK stages. However, a significant positive correlation between the SUVmax and lesion size, including the surface area of the lesion (r2 = 0.692, P = 0.0002) and the condyle width ratio (r2 = 0.365, P = 0.022), was found. The approximate volumes of the lesions measured by MRI had an average of 4.8 +/- 3.1 cm3, and also showed a significant correlation with the SUVmax (r2 = 0.853, P < 0.0001). Hence, our present results indicate that a high SUV is indicative of a large SONK lesion.

Simultaneous bilateral opening-wedge high tibial osteotomy with early full weight-bearing exercise.

Simultaneous bilateral opening-wedge high tibial osteotomies (OWHTOs), using the TomoFix fixation device and artificial bone wedges (beta-TCP) were performed on 20 knees of 10 patients with an average age of 67 years (range 53-75) at the time of the operation. We established an early weight-bearing exercise program during which patients were permitted partial weight-bearing exercise 1 week after osteotomy, with all patients performing full weight-bearing exercise at 3 weeks. The follow-up period was an average of 15 months (range 6-39). The American Knee Society Score and the Function Score were improved significantly from 46 +/- 8.1 to 92 +/- 6.8 points and 67 +/- 7.9 to 95 +/- 7.9 points, respectively. Prior to surgery, the average lateral femoro-tibial angle (FTA) during standing was 182 +/- 2.3 degrees (2 degrees anatomical varus) and significantly changed to 170 +/- 2.5 degrees (10 degrees valgus) at the time of follow-up. There were no cases of infection, non-union, or implant failure. Overall, this procedure was highly successfully in correcting knee malalignment in patients with medial compartmental osteoarthritis. In our study also, there was no evidence of correction loss, implant failure, collapse of the artificial bone wedges, or screw loosening. Simultaneous treatment of bilateral OWHTOs under a single administration of anesthesia appears to be superior to separate procedures of unilateral surgical procedures in providing the potential benefits of minimizing hospitalization, reducing costs and maximizing clinical outcomes for patients and institutions.

Clinical evaluation of the effect of attenuation correction technique on 18F-fluoride PET images.

OBJECTIVE: The purpose of this study is to evaluate effect of attenuation correction technique on 18F-fluoride positron emission tomography (PET). METHODS: We performed PET scans after the injection of 185 MBq 18F-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, Paget's 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 of 18F-fluoride PET images. The bone-to-muscle ratio analysis without attenuation correction may be of use to differentiate malignant from benign disease processes.