Katsushi Takeshita

Degenerative cervical myelopathy (DCM) is the most common cause of adult spinal cord dysfunction and leads to progressive neurological deficits in gait and hand dexterity. Handgrip strength is a recognized marker of overall muscle strength and has been linked to various clinical outcomes, including frailty and prognosis. This study aimed to evaluate the relationship between handgrip strength, frailty, and functional status in DCM patients. This cross-sectional study included 94 patients (65 males, 29 females; mean age 66.9 years) undergoing surgery for DCM. Preoperatively, we measured handgrip strength, lower extremity extension power (LEP), pinch strength, gait speed (10-m walk test), hand dexterity (counter test), and neurological function (Japanese Orthopaedic Association [JOA] score). We also assessed frailty using the 5-item modified frailty index (mFI-5) and nutritional status using the Geriatric Nutritional Risk Index (GNRI). Handgrip strength showed strong positive correlations with LEP ( r = 0.675, P < .001), gait speed ( r = 0.617, P < .001), hand dexterity ( r = 0.659, P < .001), and pinch strength ( r = 0.723, P < .001). It was also positively correlated with the total JOA score ( r = 0.468, P = .001) and negatively correlated with age (r = −0.468, P < .001) and the mFI-5 score (r = −0.464, P < .001). Handgrip strength was significantly lower in frail patients (19.5 ± 9.7 kg) than in prefrail (25.2 ± 7.1 kg) and robust patients (30.0 ± 7.5 kg) ( P < .001). After adjustment for age and sex, the associations with LEP (partial r = 0.430, P < .001), hand dexterity (partial r = 0.446, P < .001), and pinch strength (partial r = 0.560, P < .001) remained significant after Bonferroni correction, whereas the association with gait speed did not (partial r = 0.257, P = .030). Handgrip strength was associated with gait performance, dexterity, neurological function, and frailty in unadjusted analyses. After adjustment for age and sex, the strongest adjusted associations were with LEP and hand function. Handgrip strength may complement comprehensive preoperative assessment, although prospective validation is required before it can guide clinical management.

Kirschner (K) wires are widely used for fracture fixation, where curved metal surfaces contact cortical bone under press-fit conditions. However, the tribological parameters at the curved bone–implant interface remain insufficiently characterized, despite their importance for initial construct stability and accurate boundary conditions in finite element analysis. In this study, we quantified the static and kinetic coefficients of friction between bone and two clinically used K-wire materials. A custom-designed curved-contact tribometer was developed to reproduce the geometric constraints imposed by cylindrical wire insertion. Semicircular grooves were machined into rabbit humeri, and either stainless steel or titanium alloy K-wires were placed within each groove. The bone specimen was then pulled at a constant speed under a controlled normal load to measure the frictional response. The static friction coefficient differed significantly between stainless steel (0.370 ± 0.115) and titanium alloy (0.456 ± 0.099), suggesting that surface-related properties may contribute more strongly to the observed material-dependent friction than contact geometry alone. Kinetic friction followed a similar trend. Inter-bone variability exceeded intra-bone variability across measurement grooves, indicating that biological heterogeneity may dominate local surface effects. These quantitative friction coefficients provide experimentally grounded parameters for bone–implant contact modeling and may help improve the predictive accuracy of computational simulations of fracture fixation. Future work should investigate the effects of lubrication and surface topography during actual K-wire insertion.

Medial open-wedge high tibial osteotomy (OWHTO) is widely performed to correct varus malalignment associated with medial compartment osteoarthritis of the

Purpose This study aimed to elucidate the association between comorbid hypertension (HT) and diabetes mellitus (DM) (HT in DM) and clinical outcomes after cervical laminoplasty. Methods This retrospective multi-institutional study enrolled patients who underwent laminoplasty between 2008 and 2017. The primary outcome was the recovery rate of JOA score. The secondary outcome was in-hospital all-cause postoperative complications. Results This study included 1002 patients (mean age, 66 years; 30% women) who were divided into 4 groups based on the presence of medically-treated HT and/or DM. The overall incidence of DM was 17%, and the prevalence of HT was 47% in diabetic patients. Patients with HT in DM showed similar preoperative JOA scores compared to those without both HT and DM. However, patients with HT in DM showed poorer postoperative JOA scores and worse JOA-RR (non-HT/DM, 48%; DM, 43%; HT, 37%; HT in DM, 28%; p < 0.05). Patients with HT in DM tended to have a higher risk of postoperative complications (2.5%, 5.4%, 3.0%, and 7.4%; p = 0.09), especially C5 palsy (0.8%, 3.0%, 1.7%, and 4.9%; p = 0.04). After adjusting confounders, the presence of HT in DM was an independent risk factor for failure to achieve the JOA-RR MCID (JOA-RR < 42%) (OR = 3.6). Conclusions Approximately half of patients with DM had HT. HT in DM was closely associated with unfavorable surgical outcomes, including an increased incidence of in-hospital postoperative complications and an elevated risk of C5 palsy. In contrast, patients with DM alone demonstrated relatively favorable outcomes.

Purpose: Medial meniscus posterior root tears (MMPRT) are a risk factor for knee osteoarthritis. The predominant treatment for MMPRT is transtibial pullout repair, and loop suture remains the gold standard procedure. This study aimed to investigate the structural properties of the meniscus‐suture‐tibia (MST) complex after loop stitch using ultra‐high molecular weight polyethylene (UHMWPE) suture tape of different thicknesses.Methods: This study used 20 fresh porcine MMPRT model knees. All specimens were randomised into two treatment groups: (1) pullout repair using 1.3 mm suture tape (thin group, n = 10; 1.3 mm PERMATAPE, Mitek Sports Medicine) fixation and (2) pullout repair using 2.5 mm suture tape (thick group, n = 10; 2.5 mm PERMATAPE, Mitek Sports Medicine) fixation. The single‐loop stitch MS technique was utilised. The MST complex specimens were placed on a tensile tester. The structural properties of the MST complex (yield load, maximum load, liner stiffness, and elongation at failure) were identified.Results: No significant differences were found between the thin and thick groups in terms of maximum load (108.8 ± 49.6 vs. 90.1 ± 33.6 N; p = 0.34), yield load (43.8 ± 15.2 vs. 39.4 ± 15.5 N; p = 0.53), liner stiffness (12.6 ± 8.4 vs. 11.2 ± 5.5 N/mm; p = 0.45), and elongation at failure (27.1 ± 19.4 vs. 19.9 ± 10.0 mm; p = 0.32).Conclusion: The structural properties of the thickness of the different UHMWPE were comparable in MMPRT repair. Additionally, 1.3 mm PERMATAPE may demonstrate similar repair potential as 2.5 mm PERMATAPE.Level of Evidence: Level Ⅳ.

Introduction: Patient-specific instrumentation (PSI) systems are used to conduct total knee arthroplasty. PSI reduces operative time, is less invasive and easier to use, and minimizes the risk of errors by providing precise measurements and reducing operating room turnover time. However, a study on the accuracy of Prophecy Evolution PSI (Microport Inc., Arlington, TN, USA) reported that 94% were below the error margin of 1.5 mm and 90% had error margins of 1 mm. This study aimed to evaluate the accuracy of the Prophecy Evolution PSI system in terms of the thickness of “total” bony resection required to achieve adequate extension/flexion gaps and the component match ratio between preoperative planning and actual component size inserted. Methods: Comparisons were made between the sizes of femoral and tibial components planned with PSI and those inserted. The primary outcome was the average preoperative range of motion with and without matched femoral/tibial components. The study further analyzed the proportions of cases in which both the femoral and tibial components matched, neither matched, and only one of the femoral or tibial components matched. Results: The ratio of the same sizes between the PSI planning and those inserted was 50.8% (33 patients) for both the femoral and tibial components. For the femoral component alone, the ratio was 84.6% (55 patients), and for the tibial component, it was 58.4% (38 patients). A receiver-operating characteristic curve analysis indicated that flexion contracture greater than 20° was a significant prognostic factor for the PSI component match group versus the mismatch group. Discussion: Flexion contracture may cause PSI mismatch. Notably, flexion contracture greater than 20° was a significant risk factor for the PSI component match group versus the mismatch group. During preoperative planning for a patient with flexion contracture, surgeons should prepare for the possibility of inserting an undersized tibial component.