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Background and objectives: An accessory navicular (AN) bone is often classified into types 1–3 according to the Veitch classification, and symptomatic type 1 patients usually receive non-surgical treatment. However, there are cases in which AN cannot be classified into one of these three types using this classification system, and the small ossicle of type 1 AN may not be the cause of foot pain. This report aimed to present a case of symptomatic type 1 AN that required surgical treatment without the excision of the small ossicle after long-term conservative treatment had failed. Case presentation: A 15-year-old girl who was diagnosed with symptomatic type 1 AN was referred to our department. Medial-side foot pain had prevented her from playing soccer well. She had been treated conservatively for type 1 AN for more than 12 months at several orthopedic clinics. Tenderness of the prominent navicular tubercle was identified, and computed tomography and magnetic resonance imaging findings suggested that the cause of her foot pain was derived from the prominent navicular tubercle not the small ossicle itself. Osteotomy of the prominent navicular tubercle with the advancement of the tibialis posterior tendon, without excision of the ossicle, was performed. At the 12-month follow-up examination, she was completely free from foot pain, and the patient-reported outcome measures were excellent. She now plays soccer at the pre-injury level. Conclusions: We report the case of a patient with symptomatic type 1 AN who underwent osteotomy of the prominent navicular tubercle with advancement of the tibialis posterior tendon, without excision of the ossicle, and who showed favorable short-term clinical outcomes. The evaluation of symptomatic patients with AN based on the Veitch classification alone may lead to inappropriate management. The small ossicle of type 1 AN was not the cause of foot pain in the present case.

Standing up from a chair is a mechanically demanding daily motion, and its biomechanics represent motor performance. In older adults with locomotive syndrome (LS), sit-to-stand (STS) movement with adequate postural control is essential to prevent falls. This study evaluated the characteristics of dynamic balance during STS movement on older adults with LS. A total of 116 participants aged ≥65 years were divided into Non-LS, LS stage 1, and LS stage 2 groups using the LS risk test. The participants were instructed to stand on the Nintendo Wii Balance Board as quickly as possible, and the STS movement was quantified using the vertical ground reaction force (VGRF) and center of pressure (CoP). The STS score, which represented dynamic balance, was significantly different among the groups (p < 0.001). The rate of VGRF development was significantly lower in the LS stages 1 and 2 than in the Non-LS group (p < 0.001). On the other hand, the total distance of the CoP path did not differ among the groups (p = 0.211). These findings indicated a reduction of postural control in older adults with LS. The STS score emphasized the importance of balance training to prevent falls in older adults with LS.

Muscle herniation of the lower extremity, such as tibialis anterior muscle herniation (TAMH), is not a rare cause of leg pain in athletes. However, a few studies have reported surgical treatment for TAMH, and the optimal surgical procedure remains controversial. Fasciotomy was reported to be effective for patients with TAMH. However, this procedure would be associated with a risk of intraoperative injury to the superficial peroneal nerve (SPN), although no previous literature has reported this complication. This case report aimed to report a case of bilateral TAMHs in which a traumatic neuroma of the SPN developed after fasciotomy. A 16-year-old baseball player presented with painful swelling lesions of the bilateral lower extremities (1 lesion on the right, 3 lesions on the left) after sports activities. An ultrasonographic evaluation showed swelling lesions of the anterolateral parts of the bilateral lower extremities in the standing position after dashing, while these lesions were not detected in the supine position. A fasciotomy of the crural fascia was performed after conservative treatment failed. Several days after surgery, the patient presented with weakened touch sensation over the dorsal area of the left foot. At the three-month follow-up examination, a swelling lesion with hard elasticity was identified. The palpation of this lesion caused a radiating sensation in the area supplied by the SPN. He was able to return to playing baseball six months after surgery. The patient was asymptomatic without palpation of the traumatic neuroma of the SPN at the latest follow-up examination. In conclusion, the present case report suggests that orthopedic surgeons need to consider the risk of iatrogenic injury to the SPN during fasciotomy for the treatment of TAMHs. However, there may be a risk of injuring the SPN because of the many variants of the course of the SPN within the compartment of the lower extremities.

Osteochondral lesion (OCL) of the patellofemoral (PF) joint is not an uncommon cause of knee pain, and surgery is needed when conservative treatment fails. However, there is a lack of evidence regarding the optimal surgical treatment for OCL of the PF joint. Fixation of OCLs using autogenous osteochondral grafts has been reported to be effective for OCL of the knee. However, in this surgical technique, the biomechanical strength of osteochondral grafts may not be sufficient in patients with open physes due to the specific quality of the cartilage and subchondral bone given their age. There is a lack of studies reporting fixation of the OCL located in the PF joint using autogenous osteochondral grafts. We herein report a case of OCL of the femoral intercondylar groove where autogenous osteochondral grafts augmented with bioabsorbable pins were used to fix the lesion in a 14-year-old patient with open physes. Preoperative MRI revealed a completely detached OCL of the intercondylar groove (36 mm × 20 mm). Although a total of four osteochondral grafts were harvested from the non-weightbearing area of the lateral femoral condyle, cartilage detached from one of the grafts. The quality of the osteochondral grafts was considered to be insufficient for stabilization of the OCL; thus, two bioabsorbable pins were additionally inserted following fixation of the lesion using three osteochondral grafts. After two years of follow-up, postoperative functional scores were favorable without knee pain. The present case suggests that fixation of the OCL using autogenous osteochondral grafts may not be appropriate for young patients with open physes.

Smart technologies are necessary for ambient assisted living (AAL) to help family members, caregivers, and health-care professionals in providing care for elderly people independently. Among these technologies, the current work is proposed as a computer vision-based solution that can monitor the elderly by recognizing actions using a stereo depth camera. In this work, we introduce a system that fuses together feature extraction methods from previous works in a novel combination of action recognition. Using depth frame sequences provided by the depth camera, the system localizes people by extracting different regions of interest (ROI) from UV-disparity maps. As for feature vectors, the spatial-temporal features of two action representation maps (depth motion appearance (DMA) and depth motion history (DMH) with a histogram of oriented gradients (HOG) descriptor) are used in combination with the distance-based features, and fused together with the automatic rounding method for action recognition of continuous long frame sequences. The experimental results are tested using random frame sequences from a dataset that was collected at an elder care center, demonstrating that the proposed system can detect various actions in real-time with reasonable recognition rates, regardless of the length of the image sequences.

Swinging a baseball bat at a pitched ball takes less than half of a second. A hitter uses his lower extremities to generate power, and coordination of the swing motion gradually transfers power through the trunk to the upper extremities during bat–ball impact. The most important instant of the baseball swing is at the bat–ball impact, after which the direction, speed, height, and distance of the hit ball determines whether runs can be scored. Thus, analyzing the biomechanical parameters at the bat–ball impact is useful for evaluating player performance. Different motion-capture systems use different methods to identify bat–ball impact. However, the level of accuracy to detect bat–ball impact is not well documented. The study aim was to examine the required accuracy to detect bat–ball impact timing. The results revealed that ±2 ms accuracy is required to report trunk and hand kinematics, especially for higher-order time-derivatives. Here, we propose a new method using a hand-worn inertial measurement unit to accurately detect bat–ball impact timing. The results of this study will be beneficial for analyzing the kinematics of baseball hitting under real-game conditions.

Baseball hitting is a highly dynamic activity, and advanced methods are required to accurately obtain biomechanical data. Inertial measurement units (IMUs) can capture the motion of body segments at high sampling rates both indoor and outdoor. The bat rotates around the longitudinal axis of the body; thus, trunk motion plays a key role in baseball hitting. Segmental coordination is important in transferring power to a moving ball and, therefore, useful in evaluating swing kinematics. The current study aimed to investigate the validity and reliability of IMUs with a sampling rate of 1000 Hz attached on the pelvis, thorax, and hand in assessing trunk and hand motion during baseball hitting. Results obtained using the IMU and optical motion capture system (OMCS) were compared. Angular displacements of the trunk segments and spine joint had a root mean square error of 0.950) had excellent reliability for trunk kinematics along the longitudinal-axis. Hand velocities at peak and impact corresponded to the values determined using the OMCS. In conclusion, IMUs with high sampling rates are effective in evaluating trunk and hand movement coordination during hitting motion.