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Abstract Background This study aimed to examine whether the non-weight-bearing tunnel view X-ray is effective for short-term evaluation of medial meniscus posterior root tear (MMPRT) by assessing the X-ray characteristics at the initial and follow-up visits. Methods This was a retrospective longitudinal study of 26 enrolled knees diagnosed with MMPRT on magnetic resonance imaging. The distance between the medial tibial eminence and medial femoral condyle (MTE–MFC distance) and medial tibiofemoral joint (MTFJ) width were measured by obtaining non-weight-bearing tunnel view and frontal view X-ray radiographs. The initial and follow-up values at a median interval of 17 days were compared. Additionally, the correlations between the MTE–MFC distance increase rate and body mass index (BMI), age, femorotibial angle (FTA), and posterior tibial slope (PTS) were evaluated using linear regression analysis. Results The tunnel view images of the initial and follow-up X-rays showed a significant increase in the MTE–MFC distance and a significant decrease in the MTFJ width. Furthermore, a moderate correlation was observed between the change in the MTE–MFC distance and the time interval between X-rays. However, no substantial correlation was observed for the change in the MTFJ width over time. Moreover, no significant correlation was observed between the change in the MTE–MFC distance in the non-weight-bearing tunnel view and BMI, age, FTA, and PTS. Conclusions The non-weight-bearing tunnel view is highly beneficial for evaluating MMPRT progression in the short term.

The authors have been designing a post-installed anchor that fixes itself into concrete material by expanding the anchor tip in an upward direction, and conducted tensile loading tests to confirm its fundamental dynamic characteristics. The test results on three types of test specimens, with anchor morphology as a parameter, indicate that the final failure modes were all anchor bar fractures, and a stable yield strength was confirmed. Additionally, the yield strength characteristics of the proposed anchor in cases where cracks are present on the concrete surface, wherein the anchors are fixed, were experimentally confirmed.

There are a few reports on the treatment of nonunited tibial anterior cruciate ligament (ACL) avulsion fractures. To our knowledge, this is the first report of a case of nonunited tibial ACL avulsion fracture 30 years after injury. A 36-year-old woman injured her knee during a road traffic accident 30 years ago. Since then, she had persistent knee instability that was left untreated. She presented to our clinic because of knee pain she had been experiencing for a week. Radiography and computed tomography revealed tibial ACL avulsion fracture nonunions. Screw fixation with arthroscopy was performed, and bone fusion was obtained. The knee injury and osteoarthritis outcome score improved from 24 points preoperatively to 83 points postoperatively. The nonunion of intercondylar eminence fractures of the tibia, even up to 30 years after the initial injury, can be treated by osteosynthesis with arthroscopy.

Background and Objectives: Type V tibial tubercle avulsion fractures are extremely rare; therefore, information on them remains limited. Furthermore, although these fractures are intra-articular, to the best of our knowledge, there are no reports on their assessment via magnetic resonance imaging (MRI) or arthroscopy. Accordingly, this is the first report to describe the case of a patient undergoing detailed evaluation via MRI and arthroscopy. Case Presentation: A 13-year-old male adolescent athlete jumped while playing basketball, experienced discomfort and pain at the front of his knee, and fell down. He was transported to the emergency room by ambulance after he was unable to walk. The radiographic examination revealed a Type Ⅴ tibial tubercle avulsion fracture that was displaced. In addition, an MRI scan revealed a fracture line extending to the attachment of the anterior cruciate ligament (ACL); moreover, high MRI intensity and swelling due to ACL were observed, suggesting an ACL injury. On day 4 of the injury, open reduction and internal fixation were performed. Furthermore, 4 months after surgery, bone fusion was confirmed, and metal removal was performed. Simultaneously, an MRI scan obtained at the time of injury revealed findings suggestive of ACL injury; therefore, an arthroscopy was performed. Notably, no parenchymal ACL injury was observed, and the meniscus was intact. The patient returned to sports 6 months postoperatively. Conclusion: Type V tibial tubercle avulsion fractures are known to be extremely rare. Based on our report, we suggest that MRI should be performed without hesitation if intra-articular injury is suspected.

Abstract Purpose Early detection of medial meniscus posterior root tear (MMPRT) is important in preventing the rapid onset and progression of degenerative knee disease. Diagnosis is facilitated by the availability of non‐weight‐bearing X‐ray view, but information on the X‐ray characteristics of MMPRT is scarce. Here, we conducted a pilot study of the X‐ray characteristics of MMPRT on non‐weight‐bearing tunnel view. Methods We retrospectively reviewed 43 consecutive patients treated in the outpatient department for medial knee pain or popliteal pain. Patients were divided into MMPRT (21 knees) and non‐MMPRT groups (22 knees). We investigated X‐ray characteristics and magnetic resonance imaging findings. Femorotibial angle, posterior tibial slope, medial tibial eminence (MTE)–medial femoral condyle (MFC) distance (contralateral and affected sides, and difference between the two), medial tibiofemoral joint (MTFJ) width (contralateral and affected sides, and difference between the two), and meniscus radial dislocation between the groups were evaluated using the Mann–Whitney U test. The association between X‐ray characteristics and MMPRT was determined using univariate and multivariate logistic regression analyses. Results A highly significant difference between the affected and contralateral sides was seen in MTFJ width and MTE–MFC distance on non‐weight‐bearing tunnel view between the MMPRT and non‐MMPRT groups. Moreover, a difference in MTFJ width of 0.665 mm between the affected and contralateral sides was useful in predicting MMPRT. Conclusions The non‐weight‐bearing tunnel view is useful for the initial diagnosis of MMPRT. Prospective evaluation in a larger population is warranted.

The objective of this study was to propose a CPG network which can generate the swimming motion of the crawl stroke. First, the CPG network for legs performing a flutter kick was constructed by connecting the neural oscillators for the leg joints. The flutter kick motion was successfully generated by the proposed CPG network. The propulsion by the generated flutter kick motion was confirmed by the simulation of the swimming movement. Next, the CPG network for both the arms and legs were constructed, in which the neural oscillator for the arms initiated the trigger signal to start the prescribed stroke motion. By changing the intrinsic cycle of the neural oscillators for the legs, both six- and two-beat crawls could be realized. It was also found that a stable region with respect to the relationship between the intrinsic cycles of the neural oscillators for the arms and legs certainly existed for the six-beat crawl, although the intrinsic cycles of the arms were three times longer than those of the legs in this case. The propulsion by the generated swimming motion was confirmed by the simulation of the swimming movement both for the six- and two-beat crawls. Finally, the roll angle of the swimmer was fed back into the CPG network in order to restore the balance in the roll direction. Restoring the balance in the roll direction was successfully realized by the proposed feedback algorithm. The resultant motion showed a complicated behavior, such as skipping strokes.