Yun‐Rak Choi

Osteoarthritis (OA), the leading cause of pain and disability worldwide, disproportionally affects individuals with obesity. The mechanisms by which obesity leads to the onset and progression of OA are unclear due to the complex interactions among the metabolic, biomechanical, and inflammatory factors that accompany increased adiposity. We used a murine preclinical model of lipodystrophy (LD) to examine the direct contribution of adipose tissue to OA. Knee joints of LD mice were protected from s

The therapeutic application of human induced pluripotent stem cells (hiPSCs) for cartilage regeneration is largely hindered by the low yield of chondrocytes accompanied by unpredictable and heterogeneous off-target differentiation of cells during chondrogenesis. Here, we combine bulk RNA sequencing, single cell RNA sequencing, and bioinformatic analyses, including weighted gene co-expression analysis (WGCNA), to investigate the gene regulatory networks regulating hiPSC differentiation under chon

BACKGROUND: The decision to perform endoscopic versus the mini-open carpal tunnel release technique is most likely left to surgeons rather than patients with idiopathic carpal tunnel syndrome. QUESTIONS/PURPOSES: We hypothesized that (1) at 3 months after surgery, the subjective outcomes of endoscopic release, performed on one hand, and mini-incision release, performed on the other, would not differ in patients with bilateral carpal tunnel syndrome; however, (2) each patient would likely prefer

BACKGROUND: Arthroscopic management of scaphoid nonunions has been advanced as a less invasive technique that allows evaluation of associated intrinsic and extrinsic ligamentous injuries; however, few studies have documented the effectiveness of arthroscopic treatment of scaphoid nonunions and which intraarticular pathologies coexist with scaphoid nonunions. QUESTIONS/PURPOSES: (1) What are the outcomes of arthroscopic management of scaphoid nonunions as assessed by the proportion of patients ac

Biologic drug therapies are increasingly used for inflammatory diseases such as rheumatoid arthritis but may cause significant adverse effects when delivered continuously at high doses. We used CRISPR-Cas9 genome editing of iPSCs to create a synthetic gene circuit that senses changing levels of endogenous inflammatory cytokines to trigger a proportional therapeutic response. Cells were engineered into cartilaginous constructs that showed rapid activation and recovery in response to inflammation

OBJECTIVE: The purpose of this study was to compare the clinical outcomes of ulnar nerve stability-based surgery via a small incision with those of classic anterior transposition of the ulnar nerve for cubital tunnel syndrome. METHODS: From March 2008 to December 2013, 107 patients with cubital tunnel syndrome underwent simple decompression or anterior transposition via a small incision, according to an ulnar nerve stability-based decision based on an assessment of intraoperative ulnar nerve sta

BACKGROUND: Trapeziometacarpal (TMC) arthritis is treated with surgery when nonsurgical treatment fails. The best surgical option for improving pain relief, functional outcomes, and postoperative complications remains controversial. The purpose of this study was to compare clinical and radiological outcomes and complications between trapezium excision with ligament reconstruction and tendon interposition (LRTI) and pyrolytic carbon interpositional arthroplasty. METHODS: From March 2009 to August

BACKGROUND: The objectives of the present study were to compare changes in muscle excursion, total collagen, and collagen subtypes after tenotomy over time and after delayed tendon repair. METHODS: Tenotomy on the extensor digitorum tendon of the right second toes of 48 New Zealand White rabbits was performed; toes on the left leg were used as controls. Passive muscle excursion, total collagen content, and type I, III, and IV collagen contents were measured at 1, 2, 4, and 6 weeks after tenotomy

Trans-scaphoid perilunate fracture dislocations, which account for more than half of total cases of perilunate injuries, are common in young patients and occur as a result of high-energy injuries, and improper management can impair wrist alignment and function. Understanding the related wrist anatomy and pathomechanics may help surgeons evaluate and diagnose patients. Early operation to reduce and fix the injuries should be considered to achieve optimal clinical and radiological outcomes. In thi

Abstract Biologic drug therapies are effective treatments for autoimmune diseases such as rheumatoid arthritis (RA) but may cause significant adverse effects, as they are administered continuously at high doses that can suppress the immune system. Using CRISPR-Cas9 genome editing, we engineered stem cells containing a synthetic gene circuit expressing biologic drugs to antagonize interleukin-1 (IL-1) or tumor necrosis factor (TNF) in an autoregulated, feedback-controlled manner in response to ac

PURPOSE: To compare the clinical results of the arthroscopic foveal repair of the triangular fibrocartilage complex (TFCC) for distal radioulnar joint (DRUJ) instability in patients with or without generalized joint laxity. METHODS: Patients who underwent arthroscopic transosseous foveal TFCC repair of Palmer 1B foveal TFCC tears (Atzei classification class II or III) from January 2018 to October 2021 were identified. Patients treated for symptomatic DRUJ instability for more than 3 months, and