Relationship between increased knee joint line obliquity after medial open-wedge high tibial osteotomy and patient-reported outcome measures.

INTRODUCTION: This study evaluated the correlation between postoperative knee joint line obliquity after medial open-wedge high tibial osteotomy and patient-reported outcome measures excluding excessively overcorrected knees. This study further identified preoperative radiological factors related to the increased postoperative knee joint line obliquity. MATERIALS AND METHODS: We retrospectively evaluated patients who underwent medial open-wedge high tibial osteotomy between March 2013 and March 2021. Postoperative excessively overcorrected knees with hip-knee-ankle angle > 7° were excluded. We investigated radiological parameters and patient-reported outcome measures preoperatively and at the last follow-up. The following radiologic parameters were measured: hip-knee-ankle angle, weight-bearing line ratio, mechanical medial proximal tibial angle, mechanical lateral distal femoral angle, lateral distal tibial angle, joint line convergent angle, knee joint line obliquity, ankle joint line obliquity, hip abduction angle, tibial posterior slope, Carton-Deschamps index, and patella tilting angle. Clinical outcomes were evaluated using Japanese knee outcome measures. This assessment criterion is based on the Western Ontario McMaster Universities Arthritis Index and MOS Short Form 36. Multiple regression analysis was performed to evaluate the association between postoperative knee joint line obliquity and patient-reported outcome measures or preoperative radiological factors (P < .05). RESULTS: A total of 52 knees were included. The mean age at the time of the surgery was 61.6 ± 9.0 years and the mean follow-up period was 30.6 ± 10.1 months. Increased postoperative knee joint line obliquity was associated with lower Japanese knee outcome measures. The preoperative hip-knee-ankle angle was significantly associated with postoperative knee joint line obliquity. CONCLUSIONS: Increased knee joint line obliquity after medial open-wedge high tibial osteotomy is associated with inferior clinical outcomes. Care should be given to the center of the rotational angulation in around-knee osteotomy to avoid postoperative increased knee joint line obliquity. LEVEL OF EVIDENCE: Retrospective comparative study, Level III.

Satisfactory outcomes after one-stage revision anterior cruciate ligament reconstruction using rectangular tunnel technique.

PURPOSE: One-stage revision anterior cruciate ligament reconstruction (ACLR) with the anatomic rectangular tunnel (RT) technique using bone-patellar tendon-bone (BTB) grafts results in anatomically precise tunnel placement and secure graft fixation. This study evaluated knee joint laxity and clinical outcomes in terms of femoral tunnel overlap. It was hypothesised that there would be no significant differences in knee joint laxity or clinical outcomes regardless of femoral tunnel overlap. METHODS: Between 2012 and 2021, a single surgeon conducted 196 one-stage revision ACLRs with the RT technique using BTB grafts. Patients were divided based on the presence of femoral tunnel overlap. Knee joint laxity was evaluated using the Lachman test, pivot shift test, and side-to-side difference measured with a KT-1000 arthrometer. Clinical outcomes were assessed using the Lysholm score, Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) Knee Examination Form 2000. Knee joint laxity and clinical outcomes were compared between groups after a median follow-up of 2.5 years (range 2.0-8.0). RESULTS: The study included 30 and 73 patients in the overlap and non-overlap groups, respectively. No significant differences were observed in the results of the Lachman test, pivot shift test, or KT-1000 arthrometer as well as in the Lysholm, KOOS, or IKDC scores between the two groups. Based on the IKDC scores, all patients were graded as normal or nearly normal. CONCLUSION: One-stage revision ACLR with the RT technique using BTB grafts improved knee joint laxity and had favourable clinical outcomes regardless of femoral tunnel overlap. To achieve optimal results in one-stage revision ACLR, it is crucial to create a tunnel within the anatomical attachment area and ensure proper graft fixation and tensioning. LEVEL OF EVIDENCE: III.

Patient-reported outcome measures after mobile-bearing unicompartmental knee arthroplasty were better than medial opening-wedge high tibial osteotomy in early elderly patients with severe osteoarthritis.

BACKGROUND: Many countries are faced with aging populations. However, few studies have directly compared the clinical outcomes of medial opening-wedge high tibial osteotomy (OWHTO) and mobile-bearing unicompartmental knee arthroplasty (MB-UKA) in early elderly patients. Thus, we aimed to investigate the clinical outcomes after OWHTO and MB-UKA in early elderly patients with similar demographics and osteoarthritis (OA) severity. METHODS: Three hundred and fifteen OWHTO and 142 MB-UKA were performed for medial compartment OA by a single surgeon between August 2009 and April 2020. Among them, patients aged 65-74 years with more than two years of follow-up were enrolled. The patient-reported outcome measures (PROMs), including visual analog scale (VAS) score and Japanese Knee Osteoarthritis Measure (JKOM) score, were compared between both procedures preoperatively and at the last follow-up. The PROMs were compared between the groups by Kellgren-Lawrence (K-L) OA grades. RESULTS: Seventy-three OWHTO and 37 MB-UKA patients were enrolled. No significant differences were found in the distribution of age, gender, follow-up period, body mass index, and Tegner activity scale between the two procedures. The postoperative PROMs in patients with K-L grade 4 were better after MB-UKA than OWHTO at the mean follow-up of 5 years. No significant difference was found in PROMs in patients with K-L grades 2 and 3. CONCLUSION: ThePROMs after MB-UKA were superior to that after OWHTO in early elderly patients with severe OA. In particular, pain relief was better after MB-UKA than OWHTO with severe OA. Meanwhile, no significant difference in PROMs was found with moderate OA patients. LEVEL OF EVIDENCE: Level IVprospective cohort study.

Risk factors of lower extremity injuries in youth athletes.

Objective: Lower extremity sports injuries frequently occur during an individual's growth period. The object of the current study was to analyse the risk factors for lower extremity sports injuries for youth athletes. The secondary objective was to clarify the factors related to new injuries after a lower extremity injury. Methods: We extracted information on youth athletes (aged 10-15 years) with sports-related disorders. Background data and injury situations were collected via a specific application. During the follow-up period, new injuries were also recorded. The athletes were divided into two groups according to injury location (lower extremity or other). We performed a multiple logistic regression analysis to clarify the association between injury location and background data. Results: 1575 complaints of lower extremity disorders and 328 complaints in other body parts were registered. According to the multiple regression analysis, practice time per week was significantly shorter for the lower extremity group than the other locations group (OR 0.98; 95% CI 0.963 to 0.999). Athletes whose future goal was at the recreational level had a significantly low incidence of new injuries after experiencing lower extremity disorders. Conclusion: The practice environments and psychological factors should receive more attention to prevent lower extremity injuries.

IGF-1 Gene Transfer to Human Synovial MSCs Promotes Their Chondrogenic Differentiation Potential without Induction of the Hypertrophic Phenotype.

Mesenchymal stem cell- (MSC-) based therapy is a promising treatment for cartilage. However, repair tissue in general fails to regenerate an original hyaline-like tissue. In this study, we focused on increasing the expression levels for insulin-like growth factor-1 (IGF-1) to improve repair tissue quality. The IGF-1 gene was introduced into human synovial MSCs with a lentiviral vector and examined the levels of gene expression and morphological status of MSCs under chondrogenic differentiation condition using pellet cultures. The size of the pellets derived from IGF-1-MSCs were significantly larger than those of the control group. The abundance of glycosaminoglycan (GAG) was also significantly higher in the IGF-1-MSC group. The histology of the IGF-1-induced pellets demonstrated similarities to hyaline cartilage without exhibiting features of a hypertrophic chondrocyte phenotype. Expression levels for the Col2A1 gene and protein were significantly higher in the IGF-1 pellets than in the control pellets, but expression levels for Col10, MMP-13, ALP, and Osterix were not higher. Thus, IGF-1 gene transfer to human synovial MSCs led to an improved chondrogenic differentiation capacity without the detectable induction of a hypertrophic or osteogenic phenotype.

Characterization of Mesenchymal Stem Cell-Like Cells Derived From Human iPSCs via Neural Crest Development and Their Application for Osteochondral Repair.

Mesenchymal stem cells (MSCs) derived from induced pluripotent stem cells (iPSCs) are a promising cell source for the repair of skeletal disorders. Recently, neural crest cells (NCCs) were reported to be effective for inducing mesenchymal progenitors, which have potential to differentiate into osteochondral lineages. Our aim was to investigate the feasibility of MSC-like cells originated from iPSCs via NCCs for osteochondral repair. Initially, MSC-like cells derived from iPSC-NCCs (iNCCs) were generated and characterized in vitro. These iNCC-derived MSC-like cells (iNCMSCs) exhibited a homogenous population and potential for osteochondral differentiation. No upregulation of pluripotent markers was detected during culture. Second, we implanted iNCMSC-derived tissue-engineered constructs into rat osteochondral defects without any preinduction for specific differentiation lineages. The implanted cells remained alive at the implanted site, whereas they failed to repair the defects, with only scarce development of osteochondral tissue in vivo. With regard to tumorigenesis, the implanted cells gradually disappeared and no malignant cells were detected throughout the 2-month follow-up. While this study did not show that iNCMSCs have efficacy for repair of osteochondral defects when implanted under undifferentiated conditions, iNCMSCs exhibited good chondrogenic potential in vitro under appropriate conditions. With further optimization, iNCMSCs may be a new source for tissue engineering of cartilage.

Three-dimensional analysis of tarsal bone response to axial loading in patients with hallux valgus and normal feet.

BACKGROUND: Patients with hallux valgus present a variety of symptoms that may be related to the type of deformity. Weightbearing affects the deformities, and the evaluation of the load response of tarsal bones has been mainly performed using two-dimensional plane radiography. The purpose of this study was to investigate and compare structural changes in the medial foot arch between patients with hallux valgus and normal controls using a computer image analysis technique and weightbearing computed tomography data. METHODS: Eleven patients with hallux valgus and eleven normal controls were included. Computed tomograms were obtained with and without simulated weightbearing using a compression device. Computed tomography data were transferred into a personal computer, and a three-dimensional bone model was created using image analysis software. The load responses of each tarsal bone in the medial foot arch were measured three-dimensionally and statistically compared between the two groups. FINDINGS: Displacement of each tarsal bone under two weightbearing conditions was visually observed by creating three-dimensional bone models. At the first metatarsophalangeal joint, the proximal phalanges of the hallux valgus group showed significantly different displacements in multiple directions. Moreover, opposite responses to axial loading were also observed in both translation and rotation between the two groups. INTERPRETATION: Weightbearing caused deterioration of the hallux valgus deformity three-dimensionally at the first metatarsophalangeal joint. Information from the computer image analysis was useful for understanding details of the pathology of foot disorders related to the deformities or instability and may contribute to the development of effective conservative and surgical treatments.

Repair of Acute Patellar Tendon Rupture Augmented with Strong Sutures.

Rupture of the patellar tendon is an uncommon injury that requires acute surgical repair to restore the function of the knee. Multiple techniques for repair have been described in the literature. Complications with these repair techniques include rerupture and extensor lag caused by gap formation at the site of repair. Thus, many surgeons have suggested augmenting the standard repair. Several methods of augmentation have been described each with disadvantages. The purpose of this article was to present our case series of six patients with acute patella tendon ruptures treated by a novel procedure using strong sutures. In this method, eight strands of four-strong sutures run within the tendon. At the patellar site, a combination of suture button and figure eight pattern techniques is used, avoiding stress concentration. The optimal tension is applied to each suture, so as the patella might be positioned at the original placement. Then all sutures are secured onto the tibia. Postoperatively with a mean follow-up of 32.7 months (range: 25-48 months), all patients had a stable knee with mean flexion of 143.3 degrees (range: 140-150 degrees) and without any extension lag. With an improvement in the International Knee Documentation Committee score to 86.8 (range: 80-92), the excellent outcome was noted in all patients. The average postoperative Lysholm score was 98.8 (range: 97-100) and the average Kujala score was 95.2 (range: 92-97). All patients recovered to near-normal strength and stability of the patellar tendon as well as restoration of function after the operation. This augmentation technique offers a distinct advantage over previous augmentation methods and materials, and may be especially useful in managing patellar tendon rupture caused by rheumatoid arthritis or other systemic conditions. For these reasons, we recommend this procedure for acute patellar tendon ruptures.

Optimization of human mesenchymal stem cell isolation from synovial membrane: Implications for subsequent tissue engineering effectiveness.

Synovium-derived mesenchymal stem cells (SDMSCs) are one of the most suitable sources for cartilage repair because of their chondrogenic and proliferative capacity. However, the isolation methods for SDMSCs have not been extensively characterized. Thus, our aim in this study was to optimize the processes of enzymatic isolation followed by culture expansion in order to increase the number of SDMSCs obtained from the original tissue. Human synovium obtained from 18 donors (1.5 g/donor) was divided into three aliquots. The samples were minced and subjected to collagenase digestion, followed by different procedures: Group 1, Tissue fragments were removed by filtering followed by removing floating tissue; Group 2, No filtering. Only floating fragments were removed; Group 3, No fragments were removed. Subsequently, each aliquot was sub-divided into two density subgroups with half. In Group 1, the cell-containing media was plated either at high (5000 cells/cm2) or low density (1000 cells/cm2). In Groups 2 and 3, the media containing cells and tissue was plated onto the same number of culture dishes as used in Group 1, either at high or low density. At every passage, the cells plated at high density were consistently re-plated at high and those plated at low density were likewise. The expanded cell yields at day 21 following cell isolation were calculated. These cell populations were then evaluated for their osteogenic, adipogenic, and chondrogenic differentiation capabilities. The final cell yields per 0.25 g tissue in Group 1 were similar at high and low density, while those in Groups 2 and 3 exhibited higher when cultured at low density. The cell yields at low density were 0.7 ± 1.2 × 107 in Group 1, 5.7 ± 1.1 × 107 in Group 2, 4.3 ± 1.2 × 107 in Group 3 (Group 1 vs Groups 2 and 3, p < 0.05). In addition, the cells obtained in each low density subgroup exhibited equivalent osteogenic, adipogenic, and chondrogenic differentiation. Thus, it was evident that filtering leads to a loss of cells and does not affect the differentiation capacities. In conclusion, exclusion of a filtering procedure could contribute to obtain higher number of SDMSCs from synovial membrane without losing differentiation capacities.