Peripheral nerve injury causes severe loss of motor and sensory functions, consequently increasing morbidity in affected patients. An autogenous nerve graft is considered the current gold standard for reconstructing nerve defects and recovering lost neurological functions; however, there are certain limitations to this method, such as limited donor nerve supply. With advances in regenerative medicine, recent research has focused on the fabrication of tissue-engineered nerve grafts as promising alternatives to the autogenous nerve grafts. In this study, we designed a nerve guidance conduit using an electrospun poly(lactide-co-ε-caprolactone) (PLCL) membrane with a visible light-crosslinked gelatin hydrogel. The PLCL nanoporous membrane with permeability served as a flexible and non-collapsible epineurium for the nerve conduit; the inner-aligned gelatin hydrogel paths were fabricated via 3D printing and a photocrosslinking system. The resultant gelatin hydrogel with microgrooved surface pattern was established as a conducting guidance path for the effective regeneration of axons and served as a reservoir that can incorporate and release bioactive molecules. From in vivo performance tests using a rat sciatic nerve defect model, our PLCL/gelatin conduit demonstrated successful axonal regeneration, remyelination capacities and facilitated functional recovery. Hence, the PLCL/gelatin conduit developed in this study is a promising substitute for autogenous nerve grafts. STATEMENT OF SIGNIFICANCE: Nerve guidance conduits (NGCs) are developed as promising recovery techniques for bridging peripheral nerve defects. However, there are still technological limitations including differences in the structures and components between natural peripheral nerve and NGCs. In this study, we designed a NGC composed of an electrospun poly(lactide-co-ε-caprolactone) (PLCL) membrane and 3D printed inner gelatin hydrogel to serve as a flexible and non-collapsible epineurium and a conducting guidance path, respectively, to mimic the fascicular structure of the peripheral nerve. In particular, in vitro cell tests clearly showed that gelatin hydrogel could guide the cells and function as a reservoir that incorporate and release nerve growth factor. From in vivo performance tests, our regenerative conduit successfully led to axonal regeneration with effective functional recovery.

Background: A locked thumb metacarpophalangeal joint is a rare condition that presents as restricted joint motions with mild hyperextension deformity, usually after a relatively minor hyperextension injury. Owing to the limitations of radiographs, computed tomography is a useful diagnostic imaging modality for assessing sesamoid displacement. However, despite its convenience, ultrasound findings of the locked thumb have rarely been reported. Here, we report a case of a locked thumb metacarpophalangeal joint diagnosed and followed-up using ultrasound. Case presentation: A 15-year-old boy with a locked thumb metacarpophalangeal joint presented to our hospital. On physical examination, the 1st metacarpophalangeal joint was found to be hyperextended, and active and passive flexions were not possible. While radiographs were inconclusive, ultrasound revealed radial sesamoid entrapment at the 1st metacarpophalangeal joint causing locking. After closed manual reduction, metacarpophalangeal motions recovered. Success of the reduction was also confirmable by ultrasound. Conclusions: Ultrasound can be a feasible modality to diagnose a locked thumb metacarpophalangeal joint and immediately judge the success or failure of the reduction.

Purpose: Ultrasonography (US) and magnetic resonance imaging (MRI), which has better resolution, have been suggested as appropriate diagnostic tools for digits; however, comparative studies of both modalities are scarce. This study compared the diagnostic performance of high-resolution US and MRI in characterizing subungual glomus tumors. Methods: We retrospectively analyzed the data of consecutive patients who were examined with high-resolution US and MRI before surgical exploration for subungual tumors from January 2017 to April 2020. The patients’ clinical data and radiological findings were collected. Historical reports for diagnostic confirmation and measurements of mass size were reviewed. We conducted the McNemar test and evaluated the degree of agreement between the size measurements made using both techniques.Results: Overall, 22 patients (age range, 19–72 years) underwent surgical exploration and had subungual glomus tumors. The mean duration from initial symptom presentation to diagnosis was 7 years (range, 5–30) years. Only nine patients (40.9%) presented with the symptomatic triad of pain, cold sensitivity, and tenderness. MRI detected lesions in 19 cases (86.4%); three cases (13.6%) were undetected. Contrastingly, US was able to detect all lesions. Nine patients (40.9%) had visibly rich blood flow in tumor tissues on Doppler US. MRI and US showed bone erosion in eight and 15 cases, respectively. Conclusion: The detection rate of high-resolution US for subungual glomus tumors was as high as that of MRI. US can be applied easily and quickly and can be more useful as a primary diagnostic tool.

Purpose: The excision of subungual glomus tumors on the distal phalanx may cause nail deformities. Herein, we report our nail-sparing and sub-nail bed approach for the excision of subungual glomus tumors, which enables subungual glomus tumor excision without removal of the nail plate and further allows access to the tumor mass by dissecting beneath the nail bed and germinal matrix to minimize postoperative pain and nail bed injury. Therefore, the present article describes this operative approach and reports surgical outcomes with respect to patient satisfaction, pain, and the final postoperative nail shape.Methods: Thirty-two cases of clinically diagnosed subungual glomus tumors treated with this approach were retrospectively evaluated. Mean pain scores were measured at 1 week postoperatively and at the last follow-up. Patients were asked for their subjective opinion regarding the final nail shape, and their responses were assessed as “satisfied” or “unsatisfied.” The objective results for the final nail shape were graded as “excellent,” “good,” or “poor” by two orthopedic hand surgeons.Results: The mean postoperative pain score (visual analog scale) at 1 week was 1.8. No patients reported pain at the last follow-up. Subjectively, 96.6% of patients were satisfied with the operation. Objectively, the postoperative nail shape was excellent in 9.3% of cases, good in 87.5%, and poor in 3.1%.Conclusion: This approach provides minimal postoperative pain, high patient satisfaction, and favorable cosmetic outcomes with respect to the nail shape by avoiding removal of the nail plate and incision of the nail bed and germinal matrix.