Yasushi Akamatsu

Fractures Around the Lateral Cortical Hinge After a Medial Opening-Wedge High Tibial Osteotomy: A New Classification of Lateral Hinge Fracture

PURPOSE The purpose of this study was to determine the frequency of lateral hinge fractures after opening-wedge high tibial osteotomy and investigate the patterns of fracture and their clinical outcome. METHODS We analyzed 104 knees in 93 patients with a mean age of 68 ± 7 years. Of the knees, 74 were diagnosed as having primary osteoarthritis and 30 with osteonecrosis. The mean follow-up period was 41 months. Lateral hinge fractures were classified as follows: type I, the fracture reaches just proximal to or within the tibiofibular joint; type II, the fracture reaches the distal portion of the proximal tibiofibular joint; and type III, a lateral plateau fracture. A standard postoperative rehabilitation protocol was used for type I fractures, 3 of 5 patients with type II fractures were treated with non-weight bearing, and type III fractures were treated with non-weight bearing until visible callus formation. RESULTS The Knee Society scores for the knee and for function showed improvement from 49 ± 11 to 91 ± 7.7 points and from 62 ± 13 to 95 ± 8.2 points, respectively. Lateral cortex fractures were observed in 26 knees (25%): 19 type I, 5 type II, and 2 type III. In the type II fracture group, 2 of 5 patients were judged to have a delayed bone union. There were 2 cases of infection (2%) and 1 case of traumatic neuroma (1%) but no instances of implant failure, nonunion, or deep vein thrombosis among our patient cohort. CONCLUSIONS High tibial osteotomy patients treated with a combination of TomoFix (Synthes, Bettlach, Switzerland) and bone substitute were able to walk with full weight bearing 2 weeks after surgery. No complications were seen in 19 patients with type I fractures. Of 5 patients with type II fractures, 2 had delayed unions with a correction loss of 3° and 7°, respectively. LEVEL OF EVIDENCE Level IV, therapeutic case series.

Changes in osteosclerosis of the osteoarthritic knee after high tibial osteotomy.

Radiographically demonstrated osteosclerosis was quantitatively evaluated in knees with medial compartmental osteoarthritis by dual xray absorptiometry. Bone density was measured in various areas of 144 knees with medial compartmental osteoarthritis, 23 knees of which were treated with high tibial osteotomy. The bone mineral density of the medial femoral and tibial condyles was greater than that of the lateral femoral and tibial condyles in all knees with medial compartmental osteoarthritis. The ratios of bone mineral density of the medial condyles to that of the lateral condyles were found to increase significantly with the progression of osteoarthritis. There was a significant positive regression line correlation between those ratios and the increase of varus deformity as expressed by the standing femorotibial angle. The former were calculated to be 1.0 when the latter was nearly 170 degrees (10 degrees anatomic valgus angulation). The ratio of bone mineral density of the medial femoral condyles to the lateral femoral condyles decreased sharply in all 23 knees within 1 year after high tibial osteotomy.

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.

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.

In vitro stability of open wedge high tibial osteotomy with synthetic bone graft.

It has been predicted that significant stress will be applied to the plate and lateral cortical hinge of an osteotomy site when early full weight bearing is commenced after an open wedge high tibial osteotomy. We hypothesized that the stress concentration on the plate or at the lateral cortical hinge would be reduced by inserting bone substitutes into the osteotomy gap. Two different types of tibia model were investigated: Group A, fixation with TomoFix with the osteotomy site left as an open space; and Group B, two beta-TCP wedges are inserted into osteotomy site and fixed with TomoFix. Stress at five points was measured using strain gauges. Specimens were mounted onto a testing machine with an FTA (femoro-tibial angle) of 170 degrees . Cyclic load tests and an ultimate load test were then performed. The mean stress on the plate was measured at 15.5+/-1.8Mpa in Group A. On the other hand, this value in Group B was only 9.52+/-2.1Mpa and this was a significant difference (P<0.01). The mean stress on the lateral hinge in Groups A and B was 3.31+/-0.5 and 2.49+/-0.2, respectively which was also a significant difference (P<0.05). The mean maximum breaking load in Group A was 2500+/-280N and in Group B 4270+/-420N which was a significant difference (P<0.01). Hence, for OWHTO procedures, the use of beta-TCP wedges and TomoFix is thus likely to improve the initial axial and possibly rotational stability at the osteotomy site in comparison with methods that leave the osteotomy gap open.

Medial versus lateral condyle bone mineral density ratios in a cross-sectional study: a potential marker for medial knee osteoarthritis severity.

To assess the association of bone mineral density (BMD) of the femoral and tibial condyles with knee pain and disease severity in women with symptomatic medial knee osteoarthritis (OA).

Relationship Between Low Bone Mineral Density and Varus Deformity in Postmenopausal Women with Knee Osteoarthritis

Objective. To assess the relationship between bone mineral density (BMD) and varus deformity arising from bone structural changes caused by knee osteoarthritis (OA) in postmenopausal women. Methods. This cross-sectional study involved 135 consecutive postmenopausal female patients who had varus knee OA and a Kellgren-Lawrence grade ≥ 2. Knee radiographs were obtained with the patient standing on one leg, and subjects were classified into 3 tertile groups according to femorotibial angle, which was taken as a measure of varus knee OA severity. We also measured the 3 subangles that make up the femorotibial angle, and focused on the varus inclination of the tibial plateau. BMD was measured in the lumbar spine, femoral neck, and medial and lateral tibial condyles using dual-energy X-ray absorptiometry. Differences between femorotibial angle tertile groups were assessed, and associations between femorotibial sub-angles and BMD values at various points were evaluated. Results. After adjustment for age and body mass index, there was no significant association between the varus inclination of the tibial plateau and lumbar spine BMD. A weak but statistically significant negative correlation existed between varus inclination of the tibial plateau and BMD at the ipsilateral proximal femur and lateral tibial condyle. Conclusion. Varus inclination of the tibial plateau was significantly more severe in the femorotibial angle tertile 3 group, and in patients with lower BMD in the ipsilateral lower limb. Varus knee OA may result not only from cartilage loss but also from structural changes of the bone.

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

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.