Developing a Novel Prosthetic Hand with Wireless Wearable Sensor Technology Based on User Perspectives: A Pilot Study.

Myoelectric hands are beneficial tools in the daily activities of people with upper-limb deficiencies. Because traditional myoelectric hands rely on detecting muscle activity in residual limbs, they are not suitable for individuals with short stumps or paralyzed limbs. Therefore, we developed a novel electric prosthetic hand that functions without myoelectricity, utilizing wearable wireless sensor technology for control. As a preliminary evaluation, our prototype hand with wireless button sensors was compared with a conventional myoelectric hand (Ottobock). Ten healthy therapists were enrolled in this study. The hands were fixed to their forearms, myoelectric hand muscle activity sensors were attached to the wrist extensor and flexor muscles, and wireless button sensors for the prostheses were attached to each user's trunk. Clinical evaluations were performed using the Simple Test for Evaluating Hand Function and the Action Research Arm Test. The fatigue degree was evaluated using the modified Borg scale before and after the tests. While no statistically significant differences were observed between the two hands across the tests, the change in the Borg scale was notably smaller for our prosthetic hand (p = 0.045). Compared with the Ottobock hand, the proposed hand prosthesis has potential for widespread applications in people with upper-limb deficiencies.

Association between Obesity and Short-Term Patient-Reported Outcomes following Total Knee Arthroplasty: A Retrospective Cohort Study in Japan.

Background: This study investigated the association between obesity and short-term patient-reported outcomes after total knee arthroplasty (TKA). Methods: The primary outcomes were the Western Ontario and McMaster Universities Osteoarthritis Index's (WOMAC) pain and function scores. Data were collected preoperatively and 2 and 4 weeks after surgery. Patients were stratified into three groups based on body mass index (BMI): normal weight (BMI < 24.99 kg/m2), overweight (25 ≤ BMI < 29.99 kg/m2), and obese (BMI ≥ 30 kg/m2). The associations between BMI and the WOMAC pain and function scores were assessed using generalized linear mixed models. Results: Among the 102 patients (median age: 75.0, women [85.3%]), 29.4%, 48.0%, and 22.5% were normal weight, overweight, and obese, respectively. The mean pain and function scores at baseline were similar across the BMI-stratified groups (p = 0.727 and 0.277, respectively). The pain score significantly improved 2 weeks post-surgery (p = 0.001). The function score improved significantly 4 weeks post-surgery (p < 0.001). The group and group-by-time interaction effects lacked statistical significance. Conclusions: All patients statistically and clinically showed relevant pain reduction and functional improvement shortly after TKA, irrespective of their obesity status. These data may help healthcare professionals discuss the expectations of pain amelioration and functional improvement with TKA candidates.

Absolute reliability of Young's modulus of the soleus muscle and Achilles tendon measured using shear wave elastography in healthy young males.

Background: Stiffness of the soleus muscle (SOL) and Achilles tendon (AT) are associated with Achilles tendinitis and medial tibial stress syndrome. Therefore, reliable SOL and AT stiffness measurements are important for monitoring clinical progress. However, little is known about the absolute reliability of the stiffness measurements of SOL and AT in different ankle positions. This study aimed to determine the absolute reliability of the Young's modulus measurements of the SOL and AT in different ankle positions in healthy young males. Methods: This study included 33 healthy young males. SOL and AT stiffnesses were measured using Young's modulus and shear-wave elastography (SWE). Measurements were taken while the participants were kneeling, with their knees flexed to 90°, and the upper body supported by a table. Ultrasound images were recorded at ankle dorsiflexion angles of -10°, 0°, and 10°. The same measurements were repeated 15 min after the first measurement. Bland-Altman plots were used to verify the type or amount of error and 95 % confidence interval of the minimal detectable change (MDC95) values of the measurements. Results: Bland-Altman plots identified that there was no fixed or proportional bias and that there was good agreement between the first- and second-time measurements of the SOL and AT, respectively, among all angles. The MDC95 of the Young's modulus of SOL at -10°, 0°, and 10° of ankle dorsiflexion were 5.6 kPa, 7.0 kPa, and 10.1 kPa, respectively, and AT were 15.8 kPa, 16.4 kPa, and 17.8 kPa, respectively. Conclusion: Young's modulus measurements of the SOL and AT using SWE can be used to quantify elastic properties with high confidence. Clinically, assessing changes in the Young's moduli of the SOL and AT using SWE may help determine the effectiveness of interventions.

Femtosecond Laser Irradiation to Zirconia Prior to Calcium Phosphate Coating Enhances Osteointegration of Zirconia in Rabbits.

Calcium phosphate (CaP) coating of zirconia and zirconia-based implants is challenging, due to their chemical instability and susceptibility to thermal and mechanical impacts. A 3 mol% yttrium-stabilized tetragonal zirconia polycrystal was subjected to femtosecond laser (FsL) irradiation to form micro- and submicron surface architectures, prior to CaP coating using pulsed laser deposition (PLD) and low-temperature solution processing. Untreated zirconia, CaP-coated zirconia, and FsL-irradiated and CaP-coated zirconia were implanted in proximal tibial metaphyses of male Japanese white rabbits for four weeks. Radiographical analysis, push-out test, alizarin red staining, and histomorphometric analysis demonstrated a much improved bone-bonding ability of FsL-irradiated and CaP-coated zirconia over CaP-coated zirconia without FsL irradiation and untreated zirconia. The failure strength of the FsL-irradiated and CaP-coated zirconia in the push-out test was 6.2-13.1-times higher than that of the CaP-coated zirconia without FsL irradiation and untreated zirconia. Moreover, the adhesion strength between the bone and FsL-irradiated and CaP-coated zirconia was as high as that inducing host bone fracture in the push-out tests. The increased bone-bonding ability was attributed to the micro-/submicron surface architectures that enhanced osteoblastic differentiation and mechanical interlocking, leading to improved osteointegration. FsL irradiation followed by CaP coating could be useful for improving the osteointegration of cement-less zirconia-based joints and zirconia dental implants.

Feasibility and safety study of wearable cyborg Hybrid Assistive Limb for pediatric patients with cerebral palsy and spinal cord disorders.

Introduction: The wearable cyborg Hybrid Assistive Limb (HAL) is the world's first cyborg-type wearable robotic device, and it assists the user's voluntary movements and facilitates muscle activities. However, since the minimum height required for using the HAL is 150 cm, a smaller HAL (2S size) has been newly developed for pediatric use. This study aimed to (1) examine the feasibility and safety of a protocol for treatments with HAL (2S size) in pediatric patients and (2) explore the optimal method for assessing the efficacy of HAL. Methods: This clinical study included seven pediatric patients with postural and motor function disorders, who received 8-12 sessions of smaller HAL (2S size) treatment. The primary outcome was the Gross Motor Function Measure-88 (GMFM-88). The secondary outcomes were GMFM-66, 10-m walk test, 2- and 6-min walking distances, Canadian Occupational Performance Measure (COPM), a post-treatment questionnaire, adverse events, and device failures. Statistical analyses were performed using the paired samples t-test or Wilcoxon signed-rank test. Results: All participants completed the study protocol with no serious adverse events. GMFM-88 improved from 65.51 ± 21.97 to 66.72 ± 22.28 (p = 0.07). The improvements in the secondary outcomes were as follows: GMFM-66, 53.63 ± 11.94 to 54.96 ± 12.31, p = 0.04; step length, 0.32 ± 0.16 to 0.34 ± 0.16, p = 0.25; 2-MWD, 59.1 ± 57.0 to 62.8 ± 63.3, p = 0.54; COPM performance score, 3.7 ± 2.0 to 5.3 ± 1.9, p = 0.06; COPM satisfaction score, 3.3 ± 2.1 to 5.1 ± 2.1, p = 0.04. Discussion: In this exploratory study, we applied a new size of wearable cyborg HAL (2S size), to children with central nervous system disorders. We evaluated its safety, feasibility, and identified an optimal assessment method for multiple treatments. All participants completed the protocol with no serious adverse events. This study suggested that the GMFM would be an optimal assessment tool for validation trials of HAL (2S size) treatment in pediatric patients with posture and motor function disorders.

Gait training using a wearable robotic hip device for incomplete spinal cord injury: A preliminary study.

CONTEXT/OBJECTIVE: To explore changes in gait functions for patients with chronic spinal cord injury (SCI) before and after standard rehabilitation and rehabilitation with a wearable hip device, explore the utility of robot-assisted gait training (RAGT), and evaluate the safety and dose of RAGT. DESIGN: Single-arm, open-label, observational study. SETTING: A rehabilitation hospital. PARTICIPANTS: Twelve patients with SCI. INTERVENTIONS: Standard rehabilitation after admission in the first phase. RAGT for two weeks in the second phase. OUTCOME MEASURES: Self-selected walking speed (SWS), step length, cadence, and the 6-minute walking distance were the primary outcomes. Walking Index for SCI score, lower extremity motor score, and spasticity were measured. Walking abilities were compared between the two periods using a generalized linear mixed model (GLMM). Correlations between assessments and changes in walking abilities during each period were analyzed. RESULTS: After standard rehabilitation for 66.1 ± 36.9 days, a period of 17.6 ± 3.3 days of RAGT was safely performed. SWS increased during both periods. GLMM showed that the increase in cadence was influenced by standard rehabilitation, whereas the limited step length increase was influenced by RAGT. During RAGT, the increase in step length was related to an increase in hip flexor function. CONCLUSIONS: Gait speed in patients with SCI increased after rehabilitation, including RAGT, in the short-term. This increase was associated with improved muscle function in hip flexion at the start of RAGT.Trial Registration: This study was registered with the UMIN Clinical Trials Registry (UMIN-CTR; UMIN000042025).

Muscle Strength and Efficiency of Muscle Activities Recovery Using Single-Joint Type Hybrid Assistive Limb in Knee Rehabilitation after Anterior Cruciate Ligament Reconstruction.

Decreased muscle strength often occurs after anterior cruciate ligament (ACL) reconstruction; this can include muscle atrophy, neuromuscular dysfunction, and reduced force generation efficiency. Hybrid assistive limb (HAL) technology, which integrates an interactive biofeedback system connecting the musculoskeletal system to the brain and spinal motor nerves, offers a potential intervention. Our study, conducted from March 2018 to August 2023 using knee HAL single-joint technology, was a prospective non-randomized controlled trial involving 27 patients who had undergone arthroscopic ACL reconstruction. They were split into two groups: HAL (18 patients) and control (nine patients). Beginning 18 weeks after their surgery, the HAL group participated in three weekly sessions of knee HAL-assisted exercises. Both the HAL and control groups underwent isokinetic muscle strength tests at postoperative weeks 17 and 21. Testing utilized an isokinetic dynamometer at 60°/s, 180°/s, and 300°/s. The Limb Symmetry Index (LSI) was employed to measure side-to-side differences. The HAL group showed significant LSI improvements in peak extension torque across all testing velocities and for peak flexion torque at 60°/s and 300°/s. The rate of change in LSI for peak flexion torque at 300°/s was significantly higher post-measurements (p = 0.036; effect size = 1.089). The change rate for LSI in peak extension torque at 300°/s and all peak flexion torques showed medium to large effect sizes in Cohen's d. In conclusion, knee HAL single-joint training positively influenced muscle strength recovery and efficiency. The HAL training group exhibited superior muscle strength at various isokinetic testing velocities compared to the control group.

Anatomical Single-Bundle Anterior Cruciate Ligament Reconstruction Using a Calcium Phosphate-Hybridized Tendon Graft with More than an Average of 5 Years of Follow-Up: A Follow-Up Study of a Randomized Controlled Trial.

Calcium phosphate (CaP)-hybridized tendon grafting using an alternate soaking process improves tendon-to-bone healing in anterior cruciate ligament (ACL) reconstructions. This study aimed to compare bone tunnel enlargement, knee osteoarthritis, and clinical results between CaP-hybridized tendon grafting and conventional grafting in anatomical single-bundle ACL reconstruction. This study was a follow-up of a randomized controlled trial. Between July 2011 and December 2015, 90 patients underwent unilateral anatomical single-bundle ACL reconstructions and were randomly assigned to the CaP-hybridized tendon grafting (CaP group, n = 45; age, 27.1 [14-54] years; sex, 21 males and 24 females) or conventional grafting (control group, n = 45; age, 22.9 [13-58] years; sex, 26 males and 19 females). The randomization was performed according to the days of the week when the patients first visited the outpatient. The CaP-hybridized tendon grafting was created intraoperatively. The tendon grafts were soaked in a calcium solution for 30 s. After that, the tendon grafts were soaked in a NaHPO4 solution for 30 s. This soaking cycle between the calcium solution and the NaHPO4 solution was repeated 10 times. The bone tunnel enlargement, osteoarthritis grade, clinical score, and sports level were evaluated in patients who could be followed up for >3 years (CaP group, n = 20, average follow-up period 6.0 [5.1-6.9] years; control group, n = 15, average follow-up period 5.6 [4.3-6.9] years). Clinical scores, sports levels, and osteoarthritis grades were analyzed using a generalized linear mixed model (GLMM) based on repeated measurement data from preoperative and final observations, with time, group, sex, age, and BMI as fixed effects and the effect of individual differences as variable effects. In addition, bone-tunnel enlargements were analyzed using generalized linear models (GLM) with group, sex, age, and BMI as the main effects. Compared with the control group, the CaP group exhibited significantly reduced bone-tunnel enlargement on the femoral side (anteroposterior diameter; CaP group, 7.9% [-1.1-16.8] vs. control group, 29.2% [17.9-40.5], p = 0.004, MCID 16.05, proximal-distal diameter; CaP group, 7.9% [-1.9-17.8] vs. control group, 22.8% [10.9-34.7], p = 0.062, MCID 15.00). The osteoarthritis grades progressed in both groups (p < 0.001). The clinical scores and sports levels were not significantly different between the groups. This study suggests that the calcium phosphate-hybridized tendon graft reduces femoral bone-tunnel enlargement after anatomical single-bundle anterior cruciate ligament reconstruction in an average >5-year follow-up period. A longer follow-up period is necessary to reveal the clinical effects of the calcium phosphate-hybridized tendon grafts in anterior cruciate ligament reconstruction.

Relationship between the Young's Modulus of the Achilles Tendon and Ankle Dorsiflexion Angle at Maximum Squat Depth in Healthy Young Males.

Background and Objective: Achilles tendon (AT) stiffness can reduce ankle dorsiflexion. However, whether AT stiffness affects the ankle dorsiflexion angle at a maximum squat depth remains unclear. Therefore, we aimed to investigate the relationship between the Young's modulus of the AT and ankle dorsiflexion angle at the maximum squat depth in healthy young males using shear-wave elastography (SWE). Materials and Methods: This cross-sectional study included 31 healthy young males. AT stiffness was measured using the Young's modulus through SWE. The ankle dorsiflexion angle at the maximum squat depth was measured as the angle between the vertical line to the floor and the line connecting the fibula head and the lateral malleolus using a goniometer. Results: Multiple regression analysis identified the Young's modulus of the AT at 10° of ankle dorsiflexion (standardized partial regression coefficient [ß] = -0.461; p = 0.007) and the ankle dorsiflexion angle in the flexed knee (ß = 0.340; p = 0.041) as independent variables for the ankle dorsiflexion angle at maximum squat depth. Conclusions: The Young's modulus of the AT may affect the ankle dorsiflexion angle at the maximum squat depth in healthy young males. Therefore, improving the Young's modulus of the AT may help increase the ankle dorsiflexion angle at maximum squat depth.

Safety and Osteointegration of Titanium Screws Coated with a Fibroblast Growth Factor-2-Calcium Phosphate Composite Layer in Non-Human Primates: A Pilot Study.

Spinal instrumentation surgery for older patients with osteoporosis is increasing. Implant loosening may occur due to inappropriate fixation in osteoporotic bone. Developing implants that achieve stable surgical results, even in osteoporotic bone, can reduce re-operation, lower medical costs, and maintain the physical status of older patients. Fibroblast growth factor-2 (FGF-2) promotes bone formation; thus, coating pedicle screws with an FGF-2-calcium phosphate (FGF-CP) composite layer is hypothesized to enhance osteointegration in spinal implants. We designed a long-term implantation pilot study that estimated the safety and bone-forming efficacy of pedicle screws coated with an FGF-CP composite layer in cynomolgus monkeys. Titanium alloy screws, either uncoated (controls) or aseptically coated with an FGF-CP composite layer, were implanted in the vertebral bodies of six female adult cynomolgus monkeys (three monkeys per group) for 85 days. Physiological, histological, and radiographic investigations were performed. There were no serious adverse events, and no radiolucent areas were observed around the screws in either group. The bone apposition rate in the intraosseous region was significantly higher in the FGF-CP group than in the controls. Moreover, as analyzed by Weibull plots, the bone formation rate of the FGF-CP group exhibited a significantly higher regression line slope than the control group. These results demonstrated that there was significantly less risk of impaired osteointegration in the FGF-CP group. Our pilot study suggests that FGF-CP-coated implants could promote osteointegration, be safe, and reduce the probability of screw loosening.

Impact of Prolonged Cessation of Organized Team Training Due to the COVID-19 Pandemic on the Body Composition of Japanese Elite Female Wheelchair Basketball Athletes.

Studies on the effects of training confinement on athletes with physical impairments are limited. Hence, in this retrospective cohort study, we aimed to investigate the impact of prolonged cessation of organized team training due to the coronavirus disease 2019 pandemic on the body composition of elite female Japanese basketball athletes. Fourteen female wheelchair basketball athletes (aged ≥20 years) were enrolled. The primary outcomes were lean and adipose indices measured using whole-body dual-energy X-ray absorptiometry. The impact of prolonged organized team training cessation on body composition was investigated by comparing the body composition at baseline and post-training confinement. A reduced whole-body lean mass (p = 0.038) and percent lean mass (p = 0.022), as well as an increased percent body fat (p = 0.035), were observed after the confinement period. The regional analysis revealed reduced percent lean and increased percent fat masses in the trunk (p = 0.015 and p = 0.026, respectively) and upper limbs (p = 0.036 and p = 0.048, respectively). In conclusion, prolonged organized team training cessation reduced lean mass and increased body fat percentage, primarily in the trunk and upper limbs. Individualized training programs targeting these body regions should be implemented to improve body composition and physical conditions in athletes during and after prolonged cessation of organized team training.

Evaluation of hand functions and distal radioulnar joint instability in elite wheelchair basketball athletes: a cross-sectional pilot study.

BACKGROUND: Wrist injury affects wheelchair basketball players' performance; however, the relationship between distal radioulnar joint (DRUJ) instability and hand functions is unclear. This cross-sectional pilot study investigated DRUJ instability in elite female wheelchair basketball athletes using force-monitor ultrasonography. METHODS: Nine elite female wheelchair basketball athletes (18 wrists) were included in the study. A triangular fibrocartilage complex (TFCC) injury was confirmed using magnetic resonance imaging (MRI). Hand functions were evaluated based on the range of motion (ROM) of wrist palmar flexion, dorsiflexion, radial deviation, and ulnar deviation; grip strength; arm circumference; forearm circumference; and DRUJ instability or pain using the ballottement test. The Mann-Whitney U test was used to compare parameters between the TFCC-injured and intact wrists. Radioulnar displacement was measured using force-monitor ultrasonography and pressure data, and the displacement-to-force ratio was used as an indicator of DRUJ instability. The correlation between the DRUJ displacement-to-force ratio and each hand function assessment was evaluated using Pearson correlation coefficient for the TFCC-injured and intact wrists. A generalized linear mixed model (GLMM) was used to estimate the relationship between hand functions and DRUJ instability. RESULTS: TFCC injuries in seven wrists were confirmed using MRI findings (38.9%). The ulnar deviation ROM values of the TFCC-injured wrist (n = 7) and intact (n = 11) groups were 38.6 ± 8.0° and 48.6 ± 7.8°, respectively. The ulnar deviation ROM was significantly smaller in the TFCC-injured wrists (p = 0.02, r = - 0.54). In the TFCC-injured wrists, no correlation was observed between the displacement-to-force ratio and the hand function assessment. In contrast, the displacement-to-force ratio negatively correlated with grip strength, arm circumference, and forearm circumference in the intact wrists (Pearson correlation coefficient r = - 0.78, - 0.61, and - 0.74, respectively). The GLMM showed that the displacement-to-force ratio significantly affected grip strength, arm circumference, and forearm circumference in the intact group. CONCLUSIONS: In intact wrists, correlations were observed between hand functions such as upper arm/forearm strength and DRUJ stability evaluated using ultrasound. Maintaining and strengthening grip strength, forearm circumference, and arm circumference are associated with DRUJ stability and may be related to TFCC injury prevention in wheelchair basketball athletes. TRIAL REGISTRATION: The protocol was registered with the UMIN Clinical Trials Registry (UMIN000043343) [Date of first registration: 16/02/2021].

Use of Robot-Assisted Ankle Training in a Patient with an Incomplete Spinal Cord Injury: A Case Report.

Rehabilitation interventions are crucial in promoting neuroplasticity after spinal cord injury (SCI). We provided rehabilitation with a single-joint hybrid assistive limb (HAL-SJ) ankle joint unit (HAL-T) in a patient with incomplete SCI. The patient had incomplete paraplegia and SCI (neurological injury height: L1, ASIA Impairment Scale: C, ASIA motor score (R/L) L4:0/0, S1:1/0) following a rupture fracture of the first lumbar vertebra. The HAL-T consisted of a combination of ankle plantar dorsiflexion exercises in the sitting position, knee flexion, and extension exercises in the standing position, and stepping exercises in the standing position with HAL assistance. The plantar dorsiflexion angles of the left and right ankle joints and electromyograms of the tibialis anterior and gastrocnemius muscles were measured and compared using a three-dimensional motion analyzer and surface electromyography before and after HAL-T intervention. Phasic electromyographic activity was developed in the left tibialis anterior muscle during plantar dorsiflexion of the ankle joint after the intervention. No changes were observed in the left and right ankle joint angles. We experienced a case in which intervention using HAL-SJ induced muscle potentials in a patient with a spinal cord injury who was unable to perform voluntary ankle movements due to severe motor-sensory dysfunction.

Benefits of a Wearable Cyborg HAL (Hybrid Assistive Limb) in Patients with Childhood-Onset Motor Disabilities: A 1-Year Follow-Up Study.

Rehabilitation robots have shown promise in improving the gait of children with childhood-onset motor disabilities. This study aimed to investigate the long-term benefits of training using a wearable Hybrid Assistive Limb (HAL) in these patients. Training using a HAL was performed for 20 min a day, two to four times a week, over four weeks (12 sessions in total). The Gross Motor Function Measure (GMFM) was the primary outcome measure, and the secondary outcome measures were gait speed, step length, cadence, 6-min walking distance (6MD), Pediatric Evaluation of Disability Inventory, and Canadian Occupational Performance Measure (COPM). Patients underwent assessments before the intervention, immediately after the intervention, and at 1-, 2-, 3-month and 1-year follow-ups. Nine participants (five males, four females; mean age: 18.9 years) with cerebral palsy (n = 7), critical illness polyneuropathy (n = 1), and encephalitis (n = 1) were enrolled. After training using HAL, GMFM, gait speed, cadence, 6MD, and COPM significantly improved (all p < 0.05). Improvements in GMFM were maintained one year after the intervention (p < 0.001) and in self-selected gait speed and 6MD three months after the intervention (p < 0.05). Training using HAL may be safe and feasible for childhood-onset motor disabilities and may maintain long-term improvements in motor function and walking ability.

Clinical Trial for the Safety and Feasibility of Pedicle Screws Coated with a Fibroblast Growth Factor-2-Apatite Composite Layer for Posterior Cervical Fusion Surgery.

To solve the instrument loosening problem, we developed a fibroblast growth factor-2-calcium phosphate composite layer as a novel coating material to improve screw fixation strength. The primary aim of the present study was to demonstrate the safety and feasibility of screws coated with the FGF-2-calcium phosphate composite layer for posterior instrumented surgery of the cervical spine. The trial design was a single-arm, open-label, safety and feasibility study. Patients receiving fusion of the cervical spine from C2 (or C3) to C7 (or T1) were recruited. The primary endpoint to confirm safety was any screw-related adverse events. Seven patients who underwent posterior fusion surgery of the cervical spine were enrolled in the present study. The coated pedicle screws were inserted bilaterally into the lowest instrumented vertebrae. There was only one severe adverse event unrelated with the coated screw. Three out of the fourteen coated screws showed loosening. The present results prove the safety and feasibility of pedicle screws coated with the FGF-2-calcium phosphate composite layer for fusion surgery in the cervical spine. This is the first step to apply this novel surface coating in the field of spine surgery.

Simulating Knee-Stress Distribution Using a Computed Tomography-Based Finite Element Model: A Case Study.

This study aimed to evaluate the mechanism of progression involved in knee osteoarthritis (OA). We used the computed tomography-based finite element method (CT-FEM) of quantitative X-ray CT imaging to calculate and create a model of the load response phase, wherein the greatest burden is placed on the knee joint while walking. Weight gain was simulated by asking a male individual with a normal gait to carry sandbags on both shoulders. We developed a CT-FEM model that incorporated walking characteristics of individuals. Upon simulating changes owing to a weight gain of approximately 20%, the equivalent stress increased extensively in both medial and lower leg aspects of the femur and increased medio-posteriorly by approximately 230%. As the varus angle increased, stress on the surface of the femoral cartilage did not change significantly. However, the equivalent stress on the surface of the subchondral femur was distributed over a wider area, increasing by approximately 170% in the medio-posterior direction. The range of equivalent stress affecting the lower-leg end of the knee joint widened, and stress on the posterior medial side also increased significantly. It was reconfirmed that weight gain and varus enhancement increase knee-joint stress and cause the progression of OA.

Prevalence of Sarcopenic Obesity and Factors Influencing Body Composition in Persons with Spinal Cord Injury in Japan.

This study aims to investigate the prevalence of sarcopenic obesity and factors influencing body composition in persons with spinal cord injury (SCI) in Japan. Adults with SCI aged ≥ 20 years who underwent whole-body dual-energy X-ray absorptiometry between 2016 and 2022 were retrospectively analyzed. Data from 97 patients were examined. The primary outcome was appendicular skeletal muscle mass (ASM). Multiple linear regression analysis was conducted to assess factors influencing the lean and adipose indices in persons with SCI. Sarcopenia, obesity, and sarcopenic obesity were prevalent in 76%, 85%, and 64% of patients, respectively. Multivariate linear regression analysis revealed that sex (ß = 0.34, p < 0.001), lesion level (ß = 0.25, p = 0.007), severity (ß = 0.20, p = 0.043), and ability to walk (ß = 0.29, p = 0.006) were independently associated with ASM. Sex (ß = −0.63, p < 0.001) was independently associated with percent body fat. In conclusion, sarcopenia, obesity, and sarcopenic obesity were prevalent among patients with SCI in Japan. Female sex, tetraplegia, motor-complete injury, and inability to walk were risk factors for sarcopenia, whereas female sex was a risk factor for obesity in persons with SCI. A routine monitoring of body composition is necessary, especially among those with multiple risk factors, to identify individuals in need of preventive and therapeutic interventions.

Influence of periostin on the development of fibrocartilage layers of anterior cruciate ligament insertion.

BACKGROUND: Periostin (Postn) is thought to play a role in the formation of anterior cruciate ligament (ACL) insertion. However, the influence of Postn on the development of ACL insertion requires further understanding. This study aimed to clarify the influence of Postn on the development of fibrocartilage layers of ACL insertion. HYPOTHESIS: We hypothesized that Postn would influence the development of fibrocartilage layers of ACL insertion. MATERIALS AND METHODS: C57BL/6N wild-type (Postn+/+; n=54) and Postn knockout (Postn-/-; n=54) mice were used in this study. Six animals were euthanized at 1 d and 1, 2, 3, 4, 6, 8, 10, and 12 weeks of age in each group. The chondrocyte number, proliferation, apoptosis, safranin O-stained glycosaminoglycan (GAG) area, type II collagen staining area, tidemark length, and insertion width were evaluated. RESULTS: Chondrocyte proliferation was high up to 2 weeks in Postn+/+, while low at age 1 d; it was, especially lower in Postn-/- than in Postn+/+ at age 1 d and 1 week. Chondrocyte apoptosis was high up to age 8 weeks in Postn+/+ and at 6 weeks in Postn-/-; it was especially higher in Postn-/- than in Postn+/+ at age 1 week. The GAG stained area was thickest for age 1 d to 4 weeks in Postn+/+ and for age 2 to 6 weeks in Postn-/-. The type II collagen staining area in Postn+/+ was thicker than that in Postn-/- at age 6 and 8 weeks. The tidemark length in Postn+/+ was longer than that in Postn-/- from age 8 to 12 weeks. The insertion width in Postn+/+ was longer than that in Postn-/- from age 1 to 3 weeks. DISCUSSION: Postn decreased cell proliferation in the early postnatal phase and influenced the development of the fibrocartilage layer extracellular matrix of ACL insertion in mice. Postn may contribute to the development of methods for regeneration of the ACL insertion. LEVEL OF EVIDENCE: V; controlled laboratory study.

Safety of terminally gamma-ray-sterilized screws coated with fibroblast growth factor 2-calcium phosphate composite layers in non-human primates.

Screws coated with fibroblast growth factor 2 (FGF-2)-calcium phosphate (CP) composite layers exhibit enhanced soft tissue and bone formation and angiogenesis because of the biological activity of FGF-2. Furthermore, the mitogenic activity of the FGF-2 within the composite layers remains unchanged after gamma-ray sterilization, which may improve the storage stability prior to clinical use. However, the in vivo safeties of these screws as spinal implants remain unknown. Here, a randomized controlled trial, involving non-human primates, investigated the safety of using FGF-2-CP composite layer-coated screws after either gamma-ray sterilization or aseptic processing. Titanium alloy screws coated with FGF-2-CP composite layers and subjected to either gamma-ray sterilization at 25 kGy (GS group) or aseptic storage (AS group) were implanted into the vertebral bodies of two cynomolgus monkeys exceeding 12 weeks (day 99). Physiological, histological, and radiographic investigations were performed to evaluate the safeties of the screws. There were no serious adverse events, such as surgical site infection, significant loss of body weight, or abnormal blood test results. No radiolucent areas were observed around the screws from the GS or AS group throughout the study. In the intraosseous region, no significant differences were observed in bone and fibrous tissue apposition rates and rate of bone formation between the two groups (p = 0.49, 0.77, and 0.11, respectively). Neither tumor lesions nor accumulation of lymphocytes and neutrophils were observed in either group. Our data suggest that FGF-2-CP composite layer-coated screws subjected to terminal gamma-ray sterilization are as safe as those fabricated in aseptic processing.

Short-Term Outcome of Rehabilitation Program with Hybrid Assistive Limb after Tendon Lengthening in Patients with Cerebral Palsy.

In this study, we aimed to evaluate the short-term outcomes of a rehabilitation program with the Hybrid Assistive Limb® after soft tissue lengthening in young patients with cerebral palsy. We assessed six patients with cerebral palsy who underwent soft tissue surgery followed by gait training using the Hybrid Assistive Limb®. Clinical assessments were conducted preoperatively, before, immediately after, and at 1, 2, and 3 months after gait training. Gross Motor Function Measure was improved 5.93 ± 6.11% (mean ± standard deviation, p < 0.05), Canadian Occupational Performance Measure performance was improved 3.12 ± 1.53 points, and satisfaction was improved 3.80 ± 2.14 points (p < 0.05). The knee extension strength on the operated side was changed 7.75 ± 4.97 Nm after the intervention (p = 0.07). In ambulatory patients, gait speed was changed 8.37 ± 1.72 m/min, stride length was changed 10 ± 6.16 cm, and 6 min walking distance was changed 52 ± 16 m after the intervention. Training with the Hybrid Assistive Limb® may improve walking ability and clinical outcomes in young patients with cerebral palsy after soft tissue lengthening.