BackgroundSimulations show that paradoxical anterior femoral slide in conventional dual radius total knee arthroplasty (TKA) is initiated by sudden reduction of the femoral radius from distal to posterior. Therefore, we hypothesized that a new TKA prosthesis design with a gradually reducing femoral radius may minimize the anterior slide in navigation-based in vivo knee kinematics. The purpose of this study was to compare the kinematics of TKA in vivo using a prosthesis with a gradually reducing radius, in comparison with the conventional dual radius design.MethodsA retrospective case series report was performed for 12 knees with osteoarthritis using a CT-free navigation system. Six knees received TKA using a prosthesis with a gradually reducing femoral radius (Attune CR) and the other 6 knees underwent TKA using a conventional dual radius design (PFCΣ CR). Anterior-posterior (AP) displacement of the medial and lateral femoral condyles relative to the tibia, and kinematic patterns of the femur throughout the range of motion were compared between the groups.ResultsThe average AP displacement in the Attune CR group indicated no paradoxical anterior movement of both condyles, and kinematic data showed a medial pivot pattern. In contrast, AP displacement in the PFCΣ CR group indicated that both condyles showed paradoxical anterior movement, and kinematically both condyles moved in the same manner, showing a parallel motion pattern.ConclusionTKA using a prosthesis with a gradually reducing radius minimized paradoxical anterior slide in navigation-based in vivo knee kinematics.
Background: Considering the anti-inflammatory properties of the Japanese traditional Kampo medicine Boiogito (BO), we aimed to investigate the therapeutic effect of BO to prevent the development of knee osteoarthritis (KOA) in rats with surgically induced KOA. Methods: Destabilization of the medial meniscus (DMM) was performed to induce osteoarthritis in the right knees of 12-week-old Wistar rats under general anesthesia. The rats were orally administered 3% BO in standard powder chow for 4 weeks after surgery (controls: n = 6; sham group: n = 6; DMM group: n = 5; DMM + BO group: n = 5). During this period, the rotarod test was performed to monitor locomotive function. After 4 weeks, histological assessment was performed on the right knee. Results: Oral administration of BO improved locomotive function in the rotarod test. Walking time on postoperative days 1, 14, or later was significantly longer in the DMM + BO group than in the DMM group. Histologically, the DMM group showed significant progression of KOA, which, in the DMM + BO group, was strongly suppressed, as assessed by the Osteoarthritis Research Society International score. Conclusions: Our results showed that oral administration of BO had a clinically preventive effect on early stage posttraumatic KOA.
This is a rare case of a patient with a double-layered lateral meniscus, undergoing surgical treatment. A 17-year-old woman who was a member of a volleyball club had a two-year history of right knee pain with episodes of locking, although she had no history of trauma. She was referred to our hospital because her condition did not improve after conservative treatment. On presentation to the hospital, she had full range of motion in the right knee. McMurray’s test revealed no clicks; however, it produced pain in the lateral part. Plain radiography revealed no abnormal findings, whereas magnetic resonance imaging showed high signal in the posterior segment of the lateral meniscus and an increase in its volume. Arthroscopic findings showed an accessory meniscus with a flat surface overlying a normal-sized lateral meniscus. It was firmly connected to the posterior root and middle segment of the lower normal meniscus. The accessory meniscus was markedly mobile as revealed by probing. The patient was diagnosed with double-layered lateral meniscus and underwent resection of the accessory meniscus. Postoperatively, she initiated strengthening of muscles and range of motion training without weight-bearing restrictions. Two months postoperatively, she had completely recovered and participated in volleyball practices. In the last follow-up at 18 months, she had no restrictions in daily or sports activities.
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