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Introduction: Animal studies suggest that advanced glycation end products (AGEs) and their interaction with receptor for AGEs (RAGE) are involved in sarcopenia, but their relationship in human skeletal muscles has yet to be elucidated. We aimed to determine whether RAGE expression in human skeletal muscle is associated with serum AGE levels and sarcopenia-related changes. Methods: We retrospectively reviewed 33 consecutive women (mean age, 65 years) with distal radius fracture who had consented to donate a sample of forearm muscle for research purposes, which was taken during surgical fracture repair. The muscle RAGE expression was measured with immunohistochemistry staining and serum AGE levels using ELISA method. We compared RAGE expression and AGE levels in patients with and without sarcopenia. We also correlated RAGE expression with such clinical parameters as demographic factors, as well as sarcopenia-related changes, including grip strength, appendicular skeletal muscle mass, and muscle cross-sectional area (CSA) ratios. Results: Twelve patients (36%) were diagnosed with sarcopenia. They had a significantly higher RAGE expression (p = 0.044) and AGE level (p < 0.001) than those without sarcopenia. The RAGE expression correlated significantly with a high AGE level (r = 0.510, p = 0.011) and correlated inversely with a muscle CSA ratio (r = −0.696, p < 0.001). Discussion: This study shows that RAGE expression increases in sarcopenic patient skeletal muscles. This expression also correlates positively with serum AGE levels and inversely with muscle CSA ratios. Further studies are necessary to determine whether targeting RAGEs can be a therapeutic option for sarcopenia. [ABSTRACT FROM AUTHOR]

Trapeziectomy is performed for trapeziometacarpal (TMC) arthritis but decreased lateral pinch strength is a major source of discomfort after the surgery. The magnitude of the decrease is unclear, however, and how the pressure changes in the TMC joint is unknown. To investigate this relationship, we designed a cadaveric study to measure TMC joint pressure using a lateral pinch model, and quantitatively evaluated the effect of trapeziectomy on the pressure measurements. For 10 cadaveric forearms, physiologic forces were applied across the thumb TMC joint by loading five tendons, thereby simulating lateral pinch. Using pressure sensors, we measured the lateral pinch pressure and TMC joint pressure, which averaged 10.1 (range, 4.2–16.2) kg/cm2 and 2.0 (range, 0.8–4.4) kg/cm2, respectively. A significant correlation between the measurements was found, with an average ratio of 19% (range, 10%–27%). After trapeziectomy and interposition of the tendon ball using flexor carpi radialis, the pressure measurements were repeated under the same conditions. Significant changes were found, which averaged 5.1 (range, 1.7–10.7) kg/cm2 for lateral pinch pressure and 15.0 (range, 5.6–25.6) kg/cm2 for TMC joint pressure. In conclusion, TMC joint pressure could be measured as the ratio relative to lateral pinch pressure using a cadaveric model. After trapeziectomy, the lateral pinch strength decreased, whereas the TMC joint pressure increased. [ABSTRACT FROM AUTHOR]

Background: The distribution of subchondral bone density in a joint represents stress that is applied to the joint. Knowing this information is important for understanding the pathophysiology of osteoarthritis (OA). In the elbow, however, this has not been studied before., Questions/purposes: (1) Is advanced-stage elbow OA associated with more radially distributed subchondral bone density than earlier stages? (2) What demographic (age and sex) and radiographic (osteophyte location and carrying angle) factors are associated with increased radial shift in subchondral bone density?, Methods: Between March 2001 and December 2021, we treated 301 patients for elbow OA. We considered patients with plain radiographs and conventional CT scans as potentially eligible. Thus, 68% (206 patients) were eligible; a further 27% (80 patients) were excluded because of a history of any injury or surgery or known inflammatory joint disease, leaving 42% (126 patients) for analysis here. Their mean ± standard deviation age was 60 ± 10 years. Early OA with minimal joint space narrowing and osteophyte formation was found in 33% (42 of 126) of patients, and advanced OA was found in the remaining 67% (84 of 126). Three-dimensional distal humerus subchondral bone models were derived from CT images, and in the central intra-articulating portion, we measured the subchondral bone density in two different sites: where it articulates with the radius (SBD rad ) and with the ulna (SBD ulna ). We further defined the SBD ratio as the percent ratio of SBD rad to SBD ulna . We also evaluated osteophyte severity based on its size at the radiocapitellar and ulnotrochlear joints, and alignment through measuring the carrying angle on radiographs. To assess interobserver reliability, two orthopaedic surgeons took measurements independently from each other. All measurements had excellent intraoberver and interobserver reliabilities. Then, we compared the subchondral bone parameters between early and advanced OA and performed a multivariable analysis of the factors associated with subchondral bone parameters, including age, sex, osteophyte location, and carrying angle., Results: Radial versus ulna subchondral bone density (SBD ratio ) was modestly higher in patients with advanced OA (118% ± 17%) than in patients with early OA (109% ± 17%, mean difference 9% [95% CI 2.3% to 15.3%]; p = 0.01). With increasing radial deviation in subchondral bone density, cubitus valgus had a modest association (β = 0.46 ± 0.23; p = 0.04) and severe osteophytes at the radiocapitellar joint had a large association (β = 9.51 ± 3.06; p = 0.002)., Conclusion: According to subchondral bone density distribution, stress concentration was more radially deviated in patients with the advanced stages of elbow OA than in those with the early stages. We also found that an increase in carrying angle is associated with radial deviation of stress. A future study that examines longitudinal changes in the subchondral bone density might be required to confirm changes in stress concentration with OA progression., Clinical Relevance: This study gives us insight into the potential pathophysiology of elbow OA in relation to elbow alignment. Although debridement of osteophytes in the ulnotrochlear joint is the most frequently performed procedure in patients with advanced elbow OA, our finding suggests that some patients with an increased carrying angle might benefit from management of the radiocapitellar joint as well, or from being informed of the future development of OA in the radiocapitellar joint, because stress at this site can be increased with the advancement of OA., Competing Interests: All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2023 by the Association of Bone and Joint Surgeons.)

Purpose: We attempted a technique for patients with congenital ring-little finger metacarpal synostosis involving simultaneous interpositional allograft bone after split osteotomy of the synostosis site and distraction lengthening of the fifth metacarpal along with correction of the metacarpal joint abduction contracture. The purpose of this study was to describe the surgical technique and its outcomes., Methods: We reviewed the medical records of children with congenital ring-little finger metacarpal synostosis treated surgically at our institute. Eight hands of six children with an average age of 5.0 (range, 1.7-9.3) years were treated by simultaneous interpositional allograft bone after split osteotomy, distraction lengthening, and tenotomy of abductor digiti minimi. We measured the metacarpal head-to-capitate area ratios from serial radiographs and analyzed them according to age. We also measured the change in the intermetacarpal angle (IMA) and metacarpal length ratio during an average of 8.1 (range, 1.4-16.8) years of follow-up. These changes were compared with changes in seven hands of five children with an average age of 8.1 (range, 1.5-15.6) years treated by the same method, but without a distraction lengthening of the fifth metacarpal and followed up for an of average 12.1 (range, 4.1-19.8) years, as a control group., Results: Abnormal metacarpal head-to-capitate area ratio before surgery was normalized in all patients within the first 2 years after surgery. The IMA change averaged 39.8°, and the metacarpal length ratio changed by 17%. The control group showed an average IMA change of 36.6° and metacarpal length ratio change of 6%., Conclusions: Simultaneous interpositional allograft bone after split osteotomy of the synostosis site and distraction lengthening of the fifth metacarpal with correction of metacarpal joint abduction contracture can restore the radiographic parameters in congenital ring-little finger metacarpal synostosis. The normalized ossification of the fifth metacarpal head indicates that the surgical procedure is probably safe., Type of Study/level of Evidence: Therapeutic V., (Copyright © 2023 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)