河野 友祐

OBJECTIVES: Symptomatic hand osteoarthritis (HOA) significantly affects daily activities and quality of life, but its associations with osteoarthritis (OA) in other joints and systemic factors remain unclear. This study aimed to comprehensively assess patients with symptomatic HOA by examining their laboratory findings and radiographic features across multiple joints. METHODS: This cross-sectional study enrolled 53 patients with symptomatic HOA who initially presented to the outpatient clinic with hand pain and were subsequently diagnosed. Radiographic assessments of the hands, knees, hips, and spine were performed using the grading system of Kellgren-Lawrence (KL). The sum of the KL scores for all joints in both hands was calculated as the hand KL score. RESULTS: In total, 79.2% of patients had coexistent knee OA. Elevated triglyceride levels and erythrocyte sedimentation rates were observed in >50% of the cohort. Hand KL scores displayed weak positive correlations with C-reactive protein levels (r=0.34) and knee KL scores (r=0.35). CONCLUSIONS: This study highlights the frequent coexistence of knee OA in patients with symptomatic HOA and suggests potential links between HOA, systemic inflammation, and lipid metabolism. These findings provide insights into the multifactorial nature of HOA and underscore the importance of comprehensive evaluation in clinical practice.

CASE: A 17-year-old adolescent boy sustained right lateral clavicle physeal separation with the epiphysis displaced superiorly in the acromioclavicular joint (ACJ). The ossified epiphysis formed a painful nonunion with the clavicular metaphysis. Resection of the epiphysis has achieved an excellent outcome. CONCLUSION: Children and adolescents with lateral clavicle injuries often develop pseudodislocation of the ACJ in which the metaphysis is displaced due to physeal separation. By contrast, displacement of the unossified epiphysis is extremely difficult to diagnose both radiographically and clinically at the time of injury.

An absorbable adhesion barrier is a medical device that prevents postoperative adhesion and matches its biodegradation time with the regeneration period of its target tissues, which is important for antiadhesion effects. Physical hydrogels of Bombyx mori silk fibroin (SF) proteins are degradable in vivo. However, their biodegradation time is too long to exert antiadhesion effects. To shorten the biodegradation time of the SF hydrogels, we decreased the molecular weight (MW) of the SF proteins by alkaline treatment and prepared low-MW (LMW) SF hydrogels. The hydrogels contained less β-sheet crystalline and more amorphous structures than conventional, high-MW (HMW) SF hydrogels. Because of the potential loosened SF molecular structures in the hydrogel networks, the LMW SF hydrogels showed enhanced biodegradation (i.e., shorter in vitro enzymatic biodegradation time and faster in vivo biodegradation rate) as well as a lower affinity for plasma proteins and fibroblasts, which are involved in postoperative adhesion formation. An antiadhesion test using a rat abdominal adhesion model demonstrated that the LMW SF hydrogel applied to the abraded cecum was almost completely degraded within two weeks postimplantation, with a significantly lower adhesion severity score than that in the untreated model rat group. Conversely, the HMW SF hydrogel remained between the cecum and abdominal wall, with the same adhesion severity as that of the untreated model rat group. Therefore, we concluded that the antiadhesion effects of SF hydrogels were induced by enhanced biodegradation. The results of this study indicate the potential of LMW SF hydrogels as absorbable adhesion barriers.

INTRODUCTION AND IMPORTANCE: Synovial osteochondromatosis of the shoulder joint is predominantly primary, characterized by multiple osteochondral fragments, with reports of secondary synovial osteochondromatosis being rare. CASE PRESENTATION: The patient, a 48-year-old male, presented to our hospital with right shoulder pain persisting for several months. While there was no significant restriction in the range of motion, pain was noted during horizontal adduction and external rotation in the dependent position. Radiographs and CT scans revealed an osteochondral loose body in the glenohumeral joint and an osteophyte on the anterior margin of the glenoid cavity. A lidocaine test in the glenohumeral joint was positive, suggesting impingement by the loose body, leading to its surgical removal. Arthroscopically, the loose body was grasped and removed from the anterior aspect of the glenohumeral joint. The osteochondral fragment measured approximately 15 mm, with the total length including soft tissue being about 40 mm. Pathological findings indicated a layered arrangement of synovial cells, consistent with secondary synovial osteochondromatosis. Postoperatively, the shoulder pain improved rapidly, and follow-up was concluded six months after surgery. CLINICAL DISCUSSION: In this case, arthroscopy revealed a Hill-Sachs-like lesion and labral deficiency on the glenoid, suggesting past trauma. However, no bone defect matching the size of the loose body was observed. In secondary synovial osteochondromatosis, small osteochondral fragments can grow with nourishment from the synovium, suggesting the loose body in this case might have similarly enlarged post-trauma. CONCLUSION: The shoulder pain caused by a giant secondary synovial osteochondromatosis improved by removing the loose body arthroscopically.

A case of a vascular complication after collagenase injection and manipulation for Dupuytren's contracture in a 57-year-old Japanese man is described. The patient presented with a 10-year history of worsening primary Dupuytren's contracture. The metacarpophalangeal joint of his left little finger had a flexion contracture of 40° and was treated by collagenase injection. When the patient returned to our hospital for manipulation 24 hours later, however, his left little finger was almost completely improved because he hit his finger on the car's gear lever. Then, 9 months after collagenase injection, in the first winter, he complained of a painful and pale left little finger occurring a few times a day, lasting for about 10 minutes. Now, two years after collagenase injection, the episodes of Raynaud's phenomenon remain. Although Raynaud's phenomenon after collagenase injection and manipulation for Dupuytren's contracture is considered rare, it is a complication to be noted.

Dynamics properties of shoulder joint and muscle are experimentally identified under different musculoskeletal conditions for a digital human model with accurate dynamics. Passive swing motions of scapula and upper limb bones in cadaveric specimen with and without muscles are measured by an optical motion capture system. External forces that are applied to the scapula bone are simultaneously measured by a force plate. The dynamics identification process consists of 3 steps: 1) identify the inertial parameters of the cadaveric specimen with and without muscles respectively, 2) identify the viscosity of the glenohumeral joint from the specimen without muscles, and 3) identify the viscosity of the shoulder muscles from the specimen with muscles and the identified joint viscosity. These parameters are identified in six cadaveric specimens. Their joint viscosities are 5.33E-02 ± 1.33E-02 Nms/rad (without muscles) and 1.07E-01 ± 2.28E-02 Nms/rad (with muscle), and their muscle viscosities are 6.69E+02 ± 8.11E+02 Ns/m (mean ± SD). The identified joint viscosity corresponds with the literature value. This measurement and identification algorithm would improve the dynamics of the digital human model and realize the accurate muscle activity estimation and the motion simulation.