Two-stage ligament reconstruction with remnant preservation as treatment of knee dislocation.

OBJECTIVE: The purpose of this study was to evaluate the clinical outcomes of two-stage reconstruction (peripheral reconstruction in phase I and central anterior cruciate ligament (ACL) / posterior cruciate ligament (PCL) reconstruction in phase II) with remnant preservation for patients with knee dislocation. METHODS: A total of 70 patients (10 IIIM, 17 IIIL, and 43 IV) with knee dislocation were randomly divided into the remnant-preserved group and the simple reconstruction group. Patients underwent two-stage reconstruction, including the reconstruction of collateral ligament in phase I and the reconstruction of ACL/PCL in phase II (12 weeks after phase I). Grafts were harvested from the semitendinosus and gracilis tendons from both lower limbs. After the surgery, the joint flexion and extension, bone tunnel and ligament healing, and joint stability were evaluated. RESULTS: After the surgery, the lateral stability recovered in all patients, and X-ray revealed a good position of bone tunnel. Follow-up was performed at 12 months postoperatively and ranged from 24 to 91 months. At the final follow-up, knee flexion angle, IKDC, Lysholm, and Tegner scores were all higher in both groups compared to the preoperative period. Notably, the remnant-preserved group showed superior results in these parameters compared to the simple reconstruction group. There was statistical significance between the two groups in terms of the Lachman test. CONCLUSION: The knee function was well recovered after two-stage ligament reconstruction with remnant preservation.

Spacer-based gap balancing is useful in total knee arthroplasty: a 3-year follow-up of a retrospective study.

BACKGROUND: Which technique, gap balancing or measured resection, can obtain better femoral component alignment and soft tissue balance in total knee arthroplasty (TKA) is still controversial. This study aimed to determine whether the gap balancing technique using a modified spacer block in TKA can result in better postoperative clinical outcomes than the measured resection technique. METHODS: A total of 124 patients who underwent consecutive primary TKA between May 2016 and August 2018 were retrospectively reviewed. The gap balancing technique assisted by a modified spacer block was used in 61 patients, and the measured resection technique was used in 63 patients. The surgical, imaging and knee function outcomes of the two groups were compared. RESULTS: The thickness of the posterior medial condyle bone resection using the modified spacer block tool in gap balancing was significantly larger than that of the MR technique (P = 0.001). Compared with the measured resection group, the gap balancing group had a greater external rotation resection angle of the femur (4.06 ± 1.10° vs. 3.19 ± 0.59°, P < 0.001°). Despite these differences, the mean ROM, KSS scores, and WOMAC scores at the 6-week, 1-year, and 2-year follow-ups were not significantly different. Postoperatively, there was no significant difference between the two groups in mechanical axis measurements (P = 0.275), the number of HKA outliers (P = 0.795) or the joint line displacement (P = 0.270). CONCLUSION: The functional outcomes of the gap balancing technique based on the modified spacer are similar to those of measured resection at 3 years. Compared with the MR technique, the GB technique resulted in a greater external rotation resection angle and thicker posterior medial condylar cuts in TKA with knee varus.

Let-7a-5p inhibits BMSCs osteogenesis in postmenopausal osteoporosis mice.

PURPOSE: The aim of this study was to investigate the mechanism of let-7a-5p in osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in postmenopausal osteoporosis (PMOP) mice. METHODS: A mouse model of PMOP was established and osteoporosis model was identified by micro-CT scan. BMSCs in the sham group and PMOP group were cultured and osteogenic differentiation was induced. The expression of let-7a-5p in BMSCs was detected by qRT-PCR, and BMSCs was induced by osteogenic differentiation in sham and PMOP group. The BMSCs treated by let-7a-5p mimics, let-7a-5p inhibitor and negative control were named as let-7a-5p mimics group, mimics NC group, let-7a-5p inhibitor group and inhibitor NC group, respectively. ALP staining and alizarin red staining were used to detect osteogenic differentiation ability, qRT-PCR and western blot were used to detect the expression of Runt-related transcription factor 2 (Runx2) and Osterix. The targeting relationship between let-7a-5p and TGFBR1 were verificated by target scan and luciferase reporter gene assay. RESULTS: The PMOP mouse model was successfully established. The expression of let-7a-5p in BMSCs of PMOP group was significantly higher than that in the sham group (P < 0.05). Let-7a-5p reduced the expression of ALP and the formation of calcified nodules, while also inhibited the expression of Runx2 and Osterix. TGFBR1 is the target gene of let-7a-5p. CONCLUSION: Let-7a-5p might inhibit the osteogenic differentiation of BMSCs in PMOP mice by regulating TGFBR1.

Stimulation of Wnt/ß-Catenin Signaling to Improve Bone Development by Naringin via Interacting with AMPK and Akt.

BACKGROUND/AIMS: Naringin is a naturally existing compound in citrus fruits and has been elucidated to promote bone development and maintenance. METHODS: The biological roles of naringin were investigated in vitro using osteoblast-like UMR-106 cells, and in vivo through performing ovariectomy to mimic osteoporosis in female mice. Since Wnt/ß-catenin signaling is involved in osteoblastogenesis, the effect of naringin on Wnt/ß-catenin signaling was studied. RESULTS: Naringin promoted the mRNA and protein expressions of ß-catenin, and improved Ser552 phosphorylation on ß-catenin in UMR-106 cells, which leads to the activation of lymphoid enhancer factor (LEF)/ T-cell factor (TCF) transcription factors. The recruitments of protein kinase B (Akt) inhibitor (Akti-1/2) and AMP-activated protein kinase (AMPK) inhibitor (Dorsomorphin) reduced the influence of naringin on ß-catenin phosphorylation, suggesting naringin activates ß-catenin via regulating Akt and AMPK. In ovariectomized (OVX) mice naringin treatment improved the bone strength while AMPK and Akt inhibitors partly reversed the effect, which further proved the involvements of Akt and AMPK in the action of naringin in vivo. CONCLUSION: Our study points to a novel finding on the mechanism of naringin in facilitating bone formation via Akt and AMPK signaling.