The posterior tibial slope of the tibiofemoral joint changes after medial open wedge high tibial osteotomy (MOWHTO), but little is known about the effect of the sagittal osteotomy inclination angle on the change in the posterior tibial slope of the tibiofemoral joint. The purpose of this study was to investigate the effect of the osteotomy inclination angle in the sagittal plane on changes in the posterior tibial slope after MOWHTO by comparing how anterior and posterior inclination affect the posterior tibial slope of the tibiofemoral joint. The correlation between the osteotomy inclination angle and the postoperative posterior tibial slope angle was also assessed. Between May 2011 and November 2017, 80 patients with medial compartment osteoarthritis who underwent MOWHTO were included. The patients were divided into two groups according to the sagittal osteotomy inclination angle on the 3D reconstructed model. Patients with an osteotomy line inclined anteriorly to the medial tibial plateau line were classified into group A (58 patients). Patients with posteriorly inclined osteotomy line were classified as group P (22 patients). In the 3D reconstructed model, the preoperative and postoperative posterior tibial slope, osteotomy inclination angle relative to medial tibial plateau line in sagittal plane, and gap distance and ratio of the anterior and posterior osteotomy openings were measured. The preoperative and postoperative hip-knee-ankle angle, weight-bearing line ratio, and posterior tibial slope were also measured using plain radiographs. In the 3D reconstructed model, the postoperative posterior tibial slope significantly increased in group A (preoperative value = 9.7 ± 2.9°, postoperative value = 10.7 ± 3.0°, p < 0.001) and decreased in group P (preoperative value = 8.7 ± 2.7°, postoperative value = 7.7 ± 2.7°, p < 0.001). The postoperative posterior tibial slope (group A = 10.7 ± 3.0°, group P = 7.7 ± 2.7°, p < 0.001) and posterior tibial slope change before and after surgery (group A = 1.0 ± 0.8°, group P = −0.9 ± 0.8°, p < 0.001) also differed significantly between the groups. The Pearson correlation coefficient was 0.875 (p < 0.001) for the osteotomy inclination angle, and multivariate regression analysis showed that the only significant factor among the variables was the sagittal osteotomy inclination angle (β coefficient = 0.216, p < 0.001). The posterior tibial slope changed according to the osteotomy inclination angle in the sagittal plane after MOWHTO. The postoperative posterior tibial slope tended to increase when the osteotomy line was inclined anteriorly with respect to the medial tibial plateau line but decreased when the osteotomy line was inclined posteriorly. To avoid inadvertent change of posterior tibial slope, close attention needs to be paid to maintaining the sagittal osteotomy line parallel to the medial joint line during MOWHTO.

Background and Objectives: Intra-articular injection of adipose-derived stromal vascular fraction (SVF) has emerged as a promising regenerative treatment for knee osteoarthritis (OA) because of its heterogeneous cellular composition and potent anti-inflammatory paracrine effects. Although SVF therapy has demonstrated clinical efficacy, the timing of pain relief and the influence of SVF cell dose on early clinical outcomes remain incompletely defined. Materials and Methods: This retrospective study included 146 patients (217 knees) with Kellgren–Lawrence (K–L) grade II–IV knee OA who underwent intra-articular injection of autologous adipose-derived SVF and completed a minimum follow-up of 1 year. Pain was assessed using the visual analog scale (VAS), and patients reported the time to perceived pain improvement after treatment. Radiographic severity was evaluated using the K–L grading system. Correlation analyses were performed to assess associations between pain-related outcomes, SVF cell number, and radiographic severity. Results: VAS scores improved significantly from baseline to the final follow-up (p < 0.01). Patients reported perceived pain improvement at a mean of 18.9 ± 14.5 days after SVF injection. The mean injected dose was 7.4 × 10⁷ total SVF cells per knee, including approximately 7.0 × 10⁶ stromal cells. Higher SVF cell numbers were significantly associated with greater pain improvement and lower VAS scores at final follow-up (p < 0.001 for both). Radiographic severity was not significantly correlated with pain at final follow-up, the magnitude of pain improvement, or the time to symptom relief. No clinically relevant adverse events were observed. Conclusions: Intra-articular injection of high-dose autologous SVF was associated with rapid and clinically meaningful pain relief, with symptom improvement occurring within approximately 3 weeks after treatment. The dose-dependent association and the lack of correlation with radiographic severity suggest that early pain relief is primarily mediated by the anti-inflammatory and paracrine effects of SVF rather than immediate structural cartilage regeneration.

Background/Objectives: Patient-specific instrumentation (PSI) in total knee arthroplasty (TKA) uses preoperative three-dimensional imaging to create cutting blocks tailored to patient anatomy. However, there is debate regarding the additional benefits of PSI in terms of improved alignment or functional outcomes compared to using conventional instruments. Although PSI design has undergone continuous development, the improvements have not been incorporated. Therefore, the aim of this study was to compare the surgical time and radiological outcomes between advanced-design PSI and conventional instruments. Methods: We conducted a retrospective review of 328 patients who underwent primary TKAs using PSI for osteoarthritis and compared them with 328 matched patients who underwent TKA performed with conventional instruments during the same period (March 2023 to August 2024). We compared the surgical time and component alignment between the advanced-design PSI group and the conventional instrument group. Results: The average surgical time was significantly shorter in the advanced-design PSI group (47.6 ± 12.4 min) compared to the conventional instrument group (59.2 ± 14.2 min, p < 0.05). The advanced PSI design group had a significantly lower occurrence of outliers in hip–knee–ankle alignment (7%) compared to the conventional instrument group (36.3%). This trend was also observed in femoral coronal alignment, tibial coronal alignment, and femoral sagittal alignment. Conclusions: The use of advanced-design PSI demonstrated significantly reduced surgical time and improved alignment compared to conventional instruments. This highlights that proper design is a key factor for PSI to achieve superior biomechanical effects. Our study shows that advanced-design PSI technology has the potential to replace conventional instruments in TKA, though further research is required to determine its clinical outcomes and economic benefits.