Samuel Jaeyoon Won

Background and Objectives: Postoperative alignment after medial open-wedge high tibial osteotomy (MOWHTO) reflects both osseous correction and load-dependent joint response. We evaluated the internal radiographic performance of a prespecified threshold-based latent medial laxity (LML) adjustment and explored alternative deduction models. Materials and Methods: Seventy-two consecutive eligible knees were retrospectively analyzed. LML, defined operationally as the difference between joint-line convergence angles on supine valgus-stress and standing radiographs, was treated as a composite load-and-stress response. One-third of LML was deducted from the target correction angle when LML was ≤5°, and one-half when LML was >5°. The primary outcome was 1-year hip–knee–ankle (HKA) error within ±1.0°. Change in mechanical medial proximal tibial angle (ΔmMPTA) served as a radiographic proxy for executed osseous correction. Alternative deduction rules were compared by internal counterfactual analysis with leave-one-out cross-validation for fitted models. Results: Fifty-two knees (72.2%; 95% CI, 60.4–82.1%) were within ±1.0° of target. Mean signed error was −0.38 ± 0.95° (p = 0.001), with Bland–Altman limits of agreement from −2.25° to 1.49°. Mean ΔmMPTA was 6.03 ± 2.59°, versus a planned osseous correction of 6.81 ± 1.41°; the execution proxy averaged −0.78 ± 2.13° (p = 0.003). The residual planning component averaged +0.40 ± 2.04° (p = 0.098). In the internal comparison, the threshold rule yielded an MAE of 0.76° and 72.2% within ±1.0°, versus 1.79° and 41.7% with no adjustment. An exploratory continuous model (deduction = −1.77 + 0.736 × LML) yielded an MAE of 0.66° and 79.2% within ±1.0° (leave-one-out MAE, 0.68°). Conclusions: Threshold-based LML adjustment reproduced the individualized 1-year HKA target within ±1.0° in 72.2% of knees. This simple method appears feasible for preoperative planning; however, the small target-relative undercorrection bias warrants further refinement and prospective comparative validation.

원사무엘재윤, et al. J Korean Orthop Assoc. 2026 Mar;61(1):1-10. https://doi.org/10.4055/jkoa.2026.61.1.1

Mesenchymal stem cells (MSCs) spontaneously assemble into three-dimensional (3D) spheroids under matrix-deficient conditions such as the synovial cavity, although their functional significance has yet to be fully elucidated. In this study, we used concave microwell cultures to promote the spontaneous aggregation of adipose-derived MSCs (ASCs) from OA patients, thereby mimicking the intra-articular microenvironment. We analyzed the paracrine factors of ASC aggregates and compared it with that of conventional 2D monolayer cultures. Notably, 3D aggregation significantly increased the secretion of HGF and VEGF, whereas FGF2 levels remained relatively unchanged. These results indicate that the structural characteristics of ASC aggregates enhance the secretion of key paracrine factors involved in angiogenesis and tissue repair. To functionally evaluate the biological relevance of the secreted factors, conditioned media (CM) from ASC aggregates were applied to human articular chondrocytes. The CM significantly promoted chondrocyte proliferation, an effect that was abolished by the addition of HGF-neutralizing antibodies, thereby highlighting HGF as a central mediator of the regenerative response. Additionally, we further explored whether extracellular factors could modulate growth factor expression such as HGF. In this context, we investigated the impact of low-concentration hyaluronic acid (HA), a key synovial component widely used in OA treatment. Co-treatment with HA not only amplified the expression and secretion of HGF, VEGF, and FGF2, but also promoted ASC proliferation. ASCs forming functional aggregates may exert regenerative effects as active paracrine modulators, and the addition of low-dose hyaluronic acid is expected to further enhance this function, offering a promising strategy for MSC-based osteoarthritis therapy.

Author correction: “Comparison of outcomes of reinforced tension band wiring and precontoured plate and screw fixation in the management of Mayo type IIIB olecranon fractures”

Background: Mayo type IIIB olecranon fractures are characterized by significant displacement and comminution, presenting a challenge in selecting the appropriate fixation technique. This study compared the clinical and radiographic outcomes, complications, and reoperation rates of reinforced tension band wiring (TBW) and precontoured plate and screw fixation (PF) in the surgical treatment of Mayo type IIIB olecranon fractures.Methods: This retrospective review analyzed 24 patients diagnosed with Mayo type IIIB olecranon fractures, who were treated between 2005 and 2023. Of these, 11 patients underwent reinforced TBW, and 13 received precontoured PF. Clinical outcomes were assessed using Disabilities of the Arm, Shoulder, and Hand (DASH) scores and the Mayo Elbow Performance Score (MEPS). Radiographic outcomes focused on fracture union. Operative times, complication rates, and reoperation rates were compared between the groups.Results: Both the reinforced TBW and PF groups achieved satisfactory clinical outcomes, with no significant between-group differences in DASH and MEPS scores (P>0.05). Radiographic union was achieved in all patients. The reinforced TBW group demonstrated a significantly shorter operative time than the PF group (93.6±7.4 min vs. 132.3±13.7 min; P<0.001). Complication rates were similar between the two groups (reinforced TBW, 38.4%; PF, 36.3%), but hardware-related irritation occurred more frequently in the reinforced TBW group. Reoperations were required in 15.8% of the reinforced TBW group due to hardware irritation, whereas no reoperations were necessary in the PF group.Conclusions: Reinforced TBW and PF are both effective surgical options for managing Mayo type IIIB olecranon fractures, yielding comparable clinical and radiographic outcomes. While reinforced TBW offers shorter operative times and lower costs, PF is associated with fewer hardware-related complications. Further prospective studies are needed to optimize treatment strategies for these complex fractures.Level of Evidence: Level III.

Interleukin-6 (IL-6) expression in mesenchymal stem cells (MSCs) has been shown to play a pivotal role in modulating cartilage regeneration and immune responses, particularly in the context of diseases that involve both degenerative processes and inflammation, such as osteoarthritis (OA). However, the precise mechanism through which IL-6 and other immune-regulatory factors influence the therapeutic efficacy of autologous adipose-derived stem cells (ASCs) transplantation in OA treatment remains to be fully elucidated. This study aims to investigate the relationship between IL-6 expression in autologous ASCs isolated from OA patients and their impact on immune modulation, particularly focusing on the regulation of Receptor Activator of Nuclear factor Kappa-Β Ligand (RANKL), a key mediator of immune-driven cartilage degradation in OA. Autologous ASCs were isolated from the stromal vascular fraction (SVF) of adipose tissue obtained from 22 OA patients. The isolated ASCs were cultured and characterized using reverse transcription polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and flow cytometry to the phenotype and immune regulatory factors of MSCs. Based on IL-6 expression levels, ASCs were divided into high and low IL-6 expression groups. These groups were then co-cultured with activated peripheral blood mononuclear cells (PBMCs) to evaluate their immune-modulatory capacity, including the induction of regulatory T cells, inhibition of immune cell proliferation, and regulation of key cytokines, such as interferon-gamma (IFN-γ). Additionally, RANKL expression, a critical factor in osteoclastogenesis and cartilage degradation, was assessed in both ASC groups. High IL-6-expressing ASCs demonstrated a significantly greater capacity to inhibit immune cell proliferation and IFN-γ production compared to their low IL-6-expressing counterparts under co-culture conditions. Moreover, the group of ASCs with high IL-6 expression showed a marked reduction in RANKL expression, suggesting enhanced potential to control osteoclast activity and subsequent cartilage defect in OA. Conclusion: Autologous ASCs with elevated IL-6 expression exhibit enhanced immunomodulatory properties, particularly in regulating over-activated immune response and reducing osteoclastogenesis through RANKL suppression. These findings indicate that selecting ASCs based on IL-6 expression could enhance the therapeutic efficacy of ASC-based treatments for OA by mitigating immune-driven joint inflammation and cartilage degradation, potentially slowing disease progression.

Park KT, et al. Clin Orthop Surg. 2024 Oct;16:e65. https://doi.org/10.4055/cios24167

Kim S, et al. J Korean Med Sci. 2024 Mar;39(11):e106. https://doi.org/10.3346/jkms.2024.39.e106

Lee YK, et al. Clin Orthop Surg. 2022 Jul;14:e46. https://doi.org/10.4055/cios21192

Lee NK, et al. J Korean Med Sci. 2022 Oct;37(43):e309. https://doi.org/10.3346/jkms.2022.37.e309