Duk Hee Lee

Chawon Yun, Jun Hong Won, So Young Lee, Tae Hwan Kim, Ga Hee Kim and Jung Il Lee. Biomolecules & Therapeutics 2026;34:1087-102. https://doi.org/10.4062/biomolther.2026.047

Quantitative histomorphometric analysis of peripheral nerves is essential for assessing axonal regeneration and remyelination, but manual analysis is labor-intensive and impractical for large-scale studies. This study compared three automated morphometric approaches with conventional manual analysis to identify an efficient and reliable alternative. Six rat sciatic nerves, including three naïve nerves and three regenerating nerves following crush injury, were analyzed using semithin transverse sections stained with toluidine blue. Manual analysis by three independent observers served as the reference standard. Automated analyses were performed using Trainable Weka Segmentation, AxonDeepSeg, and AxonDeepSeg with manual refinement. Axon count, axon diameter, axon area, g-ratio, myelin thickness, and analysis time were compared. Manual analysis required the longest processing time (53.1 ± 16.5 min for naïve nerves and 63.4 ± 3.9 min for regenerating nerves), whereas automated approaches reduced analysis time by more than half, with AxonDeepSeg being the fastest (10.2 ± 0.5 min and 6.7 ± 0.2 min, respectively). Agreement between automated and manual measurements was primarily evaluated using Bland–Altman analysis (mean bias and 95% limits of agreement). Fully automated methods demonstrated variable levels of agreement, with wider limits of agreement, particularly in regenerating nerves. A hybrid workflow combining deep learning-based segmentation with selective manual refinement showed reduced bias and relatively narrower limits of agreement compared with other automated approaches, while maintaining improved time efficiency.

Aims: The aim of this nationwide population-based cohort study was to identify the risk factors associated with the development of idiopathic cubital tunnel syndrome (CuTS), and the factors which influence the requirement for surgery in these patients. Methods: We analyzed data from 43,189 patients newly diagnosed with idiopathic CuTS between January 2009 and December 2021, using the Korean National Health Insurance Service database. They were identified using diagnostic codes, procedural codes for surgery, and/or electrodiagnostic study codes. Patients with cervical radiculopathy, brachial plexopathy, polyneuropathy, previous CuTS and recent fracture, dislocation, or arthroplasty of the elbow were excluded. Age- and sex-matched controls were selected at a 1:5 ratio. Logistic regression identified risk factors for the development of CuTS, and Cox proportional hazards regression determined factors associated with surgical treatment. A false discovery rate-adjusted p-value < 0.05 was considered significant. Results: Risk factors for the development of CuTS included carpal tunnel syndrome (CTS), arthritis of the elbow, rheumatoid arthritis (RA), gout, depression, dyslipidaemia, hypertension, obesity, metabolic syndrome, diabetes, current smoking, anaemia, and hazardous alcohol drinking, in decreasing order of odds ratios. A total of 7,810 patients (18%) underwent surgery. Factors associated with surgery included CTS, arthritis of the elbow, RA, hypertension, obesity, metabolic syndrome, diabetes, current smoking, and hazardous alcohol drinking, in decreasing order of hazard ratios. Regular exercise significantly reduced the risk of both the development of CuTS and the requirement for surgery. Conclusion: In this large cohort study, we identified risk factors for the development of idiopathic CuTS and its surgical treatment, many of which parallel those for CTS. These findings may guide clinicians in risk stratification, prevention, and management of patients with idiopathic CuTS, and provide insights into the shared aetiology. Cite this article: Bone Joint J 2026;108-B(5):657–662.

Chawon Yun, So Young Lee, Jun Hong Won, Ga Hee Kim, Tae Hyun Kim and Jung Il Lee. Biomolecules & Therapeutics 2026;34:345-55. https://doi.org/10.4062/biomolther.2025.188

The relationship between distal radioulnar joint (DRUJ) involvement and subsequent arthritis or functional outcomes remains unclear. This study evaluated associations between DRUJ articular disruption, arthritis severity, and wrist function following volar locking plate fixation. We retrospectively reviewed patients with unstable distal radius fractures who underwent volar locking plate fixation and had a minimum follow-up of 1 year. Preoperative computerized tomography scans were analyzed for DRUJ articular involvement, articular step-off, and volar or dorsal subluxation. Patients were categorized by presence or absence of DRUJ involvement; presence or absence of sigmoid notch articular step-off; and degree of DRUJ subluxation (P < .05), though functional outcomes were similar. Arthritis grades and function were comparable between patients with subluxation ≥ 10% (n = 18) and < 10% (n = 39). Sigmoid notch involvement was not associated with higher DRUJ arthritis severity or impaired function, whereas articular step-off correlated with increased arthritis grades without functional deficits. These findings suggest that while sigmoid notch involvement alone may not be a major determinant of functional outcome, careful attention to reducing articular step-off may help minimize the risk of radiographic arthritis progression.

Peripheral nerve repair is considered the gold standard treatment for complete nerve transection injuries, yet achieving satisfactory functional recovery remains challenging due to muscle atrophy during the time required for axonal regeneration. This study investigated the beneficial effects of 4-aminopyridine (4-AP), a potassium channel blocker, on neural and muscular recovery. Following complete transection of the right sciatic nerve, 40 mice underwent end-to-end nerve repair using microscopic epineural sutures and were randomly assigned to either the control or 4-AP groups immediately after surgery (n = 20 per group). The experimental animals were administered intraperitoneal injections of 200 μL normal saline or soluble 4-AP at a dose of 10 μg daily. The sciatic functional index (SFI) and nerve conduction studies were measured until 12 weeks postoperatively. Morphological analyses of nerve and muscle, and Western blotting for proteins associated with muscle atrophy were performed at 3 and 12 weeks after surgery. There were no significant differences in the SFI between the two groups. Nerve conduction study showed that 4-AP treatment increased the compound muscle action potential and decreased latency. A histomorphometric study showed that 4-AP treatment increased myelin thickness, G-ratio (axonal diameter/axoglial diameter on cross-sectioned nerve), cross-sectional area of myofibrils, and minimal Feret diameter of myofibrils. Additionally, expression levels of FoxO3 and mTORC1 were lower in the 4-AP treated mice, while myogenin expression levels showed no significant difference between the groups. 4-AP treatment promotes myelination and prevents denervation-induced muscle atrophy after neurorrhaphy. These findings suggest that 4-AP may be a promising candidate for clinical consideration as an adjuvant therapy following nerve repair for transection injuries.