Seok Jung Kim

Cartilage restoration techniques combined with high tibial osteotomy (HTO) have increasingly been used to delay conversion to total knee arthroplasty. Amon

Introduction: Osteoarthritis (OA) is a degenerative joint disorder characterized by cartilage degradation, inflammation, and pain. Growing evidence indicates that dysregulation of the gut–joint axis contributes to OA progression. This study investigated the therapeutic potential of propionate, a gut-derived short-chain fatty acid, in OA. Methods: A monosodium iodoacetate (MIA)-induced OA rat model was used to evaluate the effects of propionate on pain and inflammation through behavioral assessments, histological analysis, and gut microbiota profiling. The intestinal environment was further assessed by histology, tight junction protein analysis, and microbiota characterization. Human OA chondrocytes were analyzed using qPCR and RNA sequencing following IL-1β stimulation with or without propionate treatment. Results: Propionate attenuated OA severity in MIA-induced rats by improving pain behaviors, preserving cartilage structure, reducing nociceptive and inflammatory markers, and restoring intestinal barrier function and microbial balance. In human OA chondrocytes, propionate modulated inflammatory and ECM-related gene expression, promoted autophagy, and suppressed catabolic and inflammatory cell death pathways, highlighting its therapeutic potential in OA. Discussion: Propionate, a gut-derived SCFA, alleviated pain, protected cartilage, reduced inflammation, restored gut barrier integrity, and rebalanced microbiota in OA rats. In human OA chondrocytes, it upregulated ECM-related genes, downregulated inflammatory mediators, and enhanced autophagy. These findings suggest that propionate may serve as a promising disease-modifying therapy for OA.

Background: Type I atelocollagen is used to treat full-thickness chondral lesions. However, evidence on the concentration-dependent effects of atelocollagen-based scaffolds on chondrogenesis is lacking. This study aimed to evaluate the in vitro and in vivo chondrogenic potentials of low-, intermediate-, and high-concentration atelocollagen-based scaffolds in a rabbit model of osteochondral defects. Methods: Human mesenchymal stem cells (hMSCs) were encapsulated in 3%, 6%, and 9% type I collagen gels to assess cell viability and chondrogenic differentiation in vitro. In vivo, full-thickness osteochondral defects (4 × 4 mm) were created in 24 rabbits and treated as follows: Group 1 (microfracture only), Group 2 (microfracture + 3% atelocollagen), Group 3 (microfracture + 6%), and Group 4 (microfracture + 9%). The animals were euthanized at 4, 8, or 12 weeks. Macroscopic and histological outcomes were evaluated using gross morphological assessment and modified O’Driscoll scores. Results: At 8 weeks postoperatively, Group 4 (7.17 ± 0.76) exhibited significantly higher macroscopic scores than Group 2 (3.83 ± 0.29, p < 0.001) and Group 3 (4.50 ± 0.50, p < 0.001), indicating near-complete defect filling and smooth surface restoration. At 12 weeks, Groups 2 (7.33 ± 0.58), 3 (7.50 ± 0.87), and 4 (8.00 ± 0.00) all demonstrated significantly higher macroscopic scores than Group 1 (0.17 ± 0.12, p < 0.001 for all). Histologically, all atelocollagen-treated groups (Group 2:20.77 ± 1.55; Group 3:23.5 ± 1.00; Group 4:23.67 ± 1.44) exhibited significantly higher scores than Group 1 (1.67 ± 0.29, p < 0.001), with Group 4 achieving the highest overall. Conclusion: High-concentration atelocollagen-based scaffolds significantly enhanced both the efficiency and quality of cartilage regeneration by providing mechanical support and a favorable microenvironment for chondrogenesis.

Background: Secondary osteonecrosis (ON) of the knee poses a treatment challenge, especially in young patients with systemic lupus erythematosus (SLE) requiring ongoing steroid therapy. Joint-preserving options for large osteochondral defects are limited, and there are no standardized protocols. Case presentation: We report the case of a 37-year-old female with a history of SLE and prior left total knee arthroplasty who presented with severe right knee pain and a progressive varus deformity. Imaging revealed a 4 × 2 cm osteochondral defect of the medial femoral condyle with over 10 mm depth and an 8° varus alignment. Given the patient’s young age and preference to avoid arthroplasty, we performed a combined medial opening high tibial osteotomy (HTO) and autologous collagen-induced chondrogenesis (ACIC) with iliac crest bone grafting. The procedure involved creation of large channels for graft placement and multiple drillings, followed by atelocollagen mixture gel application to enhance cartilage regeneration. The patient experienced progressive pain relief and functional improvement, achieving full weight bearing by 3 months. However, crutch-assisted ambulation was maintained until 6 months to reduce loading on the joint. Radiographs at 3, 9, and 18 months demonstrated gradual medial joint space widening. At 2-year follow-up, arthroscopic examination confirmed complete defect coverage with regenerated cartilage. No major complications occurred. Conclusion: Medial opening HTO combined with ACIC and autologous bone grafting may offer a feasible single-stage, joint-preserving solution for large osteochondral defects in steroid-induced secondary ON, expanding treatment options for young SLE patients.

Background: Delaying total knee arthroplasty is crucial for middle-aged patients with severe osteoarthritis. The long-term outcomes of high tibial osteotomy (HTO) remain uncertain. Recently, mesenchymal stem cells (MSCs) have shown promising potential in enhancing cartilage regeneration. Therefore, this study aimed to assess cartilage regeneration following the implantation of allogeneic human umbilical cord blood–derived mesenchymal stem cells (hUCB-MSCs) with HTO. Methods: In this case series, ten patients underwent hUCB-MSC implantation with HTO. The median age was 58.50 (range: 57.00–60.00) years, and the mean body mass index was 27.81 (range: 24.42–32.24) kg/m². Clinical outcomes, including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analog scale (VAS), Physical Component Score (PCS) and Mental Component Score (MCS) from the 36-Item Short-Form Health Survey (SF-36), were evaluated 6 months, 1 year, and 2 years postoperatively. Cartilage status of the medial femoral condyle (MFC) was assessed during hardware removal surgery, at least 2 years after the initial procedure, and compared with preoperative MFC cartilage status regarding lesion size and International Cartilage Repair Society (ICRS) grade. Radiological assessments included the Kellgren–Lawrence (KL) grading system for medial compartment osteoarthritis and hip–knee–ankle (HKA) angle. Results: Significant improvements were observed in WOMAC scores (preoperative: 57.00 (range: 44.75–63.00), postoperative: 27.50 (range: 22.25–28.75)), VAS scores (preoperative: 66.25 (range: 48.00–74.25), postoperative: 26.25 (range: 14.50–31.13)), SF-36 PCS (preoperative: 27.97 (range: 26.64–31.25), postoperative: 55.31 (range: 51.64–62.50)), and SF-36 MCS (preoperative: 41.04 (range: 29.95–50.96), postoperative: 63.18 (range: 53.83–65.16)) 2 years postoperatively (p = 0.002, 0.002, 0.002, and 0.020, respectively). The MFC chondral lesion demonstrated significant improvement in both lesion size (preoperative: 7.00 cm² (range: 4.38–10.50 cm²), postoperative: 0.16 cm² (range: 0.00–1.75 cm²), p = 0.002) and ICRS grade (preoperative: 4 (range: 4–4), postoperative: 1 (range: 1–2.25), p = 0.002). Additionally, the KL grade significantly decreased from 3 (range: 3–3) preoperatively to 2 (range: 2–2) postoperatively, while the HKA angle was corrected from 7.50° (range: 7.00–10.25°) preoperatively to -1.00° (range: -3.5–0.00°) postoperatively. Conclusions: hUCB-MSC implantation with HTO is an effective treatment for medial compartment osteoarthritis and varus deformities, resulting in significant improvements in cartilage regeneration and overall clinical outcomes. Trial registration: NCT04234412.

Na HS, et al. Immune Netw. 2025 Jun;25(3):e24. https://doi.org/10.4110/in.2025.25.e24

Many patients who cannot squat well in a neutral toe position can only squat in an excessively out-toeing position. This excessive out-toeing squat is thought to be caused by rotational problems of the lower extremities. In this study, we aimed to identify the cause for the inability to squat by measuring and comparing femoral and tibial torsion between an excessive out-toeing squat patient group and a control group representing the general population. Between 2008 and 2022, a patient group comprising 50 lower extremities with excessive out-toeing squats was established. A control group representing the general population was selected from patients aged 0 to 29 years, who underwent lower-extremity CT angiography between 2012 and 2022, using the Clinical Data Warehouse with exclusion criteria applied. A total of 94 lower extremities were included in the control group. The femoral torsional angle (FTA) and tibial torsional angle (TTA) of both groups were measured and compared using Student t test. Additionally, 30 each of those with the highest and lowest 30 FTA values were selected from the patient and control groups, and the TTA was compared between the high- and low-FTA groups using Student t test. The mean FTA was 0.34° (SD, 11.11°) in the patient group and 10.14° (SD, 11.85°) in the control group, with a mean difference of 9.8° and P < .001. The mean TTA was 27.95° (SD, 7.82°) in the patient group and 32.67 ° (SD, 7.58°) in the control group, with a mean difference of 4.72° (P = .001). The mean TTA was 34.3° (SD, 7.72°) in the high-FTA group and 28.17° (SD, 8.35°) in the low-FTA group, with a mean difference of 6.13° (P = .005). Patients with excessive out-toeing squat showed lower FTA and TTA values than the general population. Furthermore, although a correlation between FTA and TTA was not established through Pearson correlation analysis, a tendency was observed where a decrease in FTA was associated with a decrease in TTA. Based on these results, decreased FTA was demonstrated to be one of the major causes of excessive out-toeing squats.

Lee JS, et al. Immune Netw. 2024 Apr;24(3):e15. https://doi.org/10.4110/in.2024.24.e15