High concentration magnesium inhibits extracellular matrix calcification and protects articular cartilage via Erk/autophagy pathway.

The significant cytopathological changes of osteoarthritis are chondrocyte hypertrophy, proteoglycan loss, extracellular matrix (ECM) calcification, and terminally, the replacement of cartilage by bone. Meanwhile, magnesium ion (Mg2+ ), as the second most abundant divalent cation in the human body, has been proved to inhibit the ECM calcification of hBMSCs (human bone marrow stromal cells), hVSMCs (Human vascular smooth muscle cells), and TDSCs (tendon-derived stem cells) in vitro studies. The ATDC5 cell line, which holds chondrocyte characteristics, was used in this study as an in vitro subject. We found that Mg2+ can efficiently suppress the ECM calcification and downregulate both hypertrophy and matrix metalloproteinase-related genes. Meanwhile, Mg2+ inhibits the formation of autophagy by inhibiting Erk phosphorylation signaling and lowers the expression of LC3, and eventually effectively reduces the formation of ECM calcification in vitro. In this study, we also used destabilization of the medial meniscus (DMM)-induced osteoarthritis (OA) animal model to further confirm the protective effect of Mg2+ on articular cartilage. Compared with the control group (saline-injected), continuous intra-articular magnesium chloride (MgCl2 ) injection can significantly alleviate the severity of cartilage calcification in OA animal model. Immunofluorescence staining also revealed that saline-injected DMM group had a higher positive rate of LC3 expression in cartilage chondrocytes, compared with MgCl2 -injected DMM group. In general, Mg2+ can significantly downregulate the hypertrophic gene Runx2, MMP13, and Col10α1, upregulate the chondrogenic genes Sox9 and Col1α1, inhibit the Erk phosphorylation signaling, reduce the expression of autophagy protein LC3, and effectively inhibit the ECM calcification of ATDC5. In vivo study also proved that intra-articular injection of Mg2+ protected knee cartilage by inhibiting the autophagy formation.

[Effectiveness of patellar tendon reconstruction with LARS artificial ligament for old patellar tendon rupture].

OBJECTIVE: To explore the effectiveness of patellar tendon reconstruction by using LARS artificial ligament in treatment of old patellar tendon rupture. METHODS: A clinical data of 12 patients with old patellar ligament ruptures, who met the inclusive criteria and reconstructed with LARS artificial ligament between December 2011 and December 2017, was retrospectively analyzed. There were 8 males and 4 females with an average age of 33.5 years (range, 18-55 years). The cause of injury included traffic accident injury in 4 cases, sport injury in 5 cases, and violent injury in 3 cases. There were 5 cases in the left knee and 7 cases in the right knee. The disease duration was 2-12 weeks (mean, 2.5 weeks). The preoperative Lysholm score and Kujala score were 43.2±3.2 and 43.9±2.6, respectively. The knee range of motion was (106.5±14.7)°. The thigh circumference which was measured at 10 cm above the upper end of the patella was (40.92±1.93) cm. There were 4 cases of patellar ligament body rupture, 1 case of patella distal pola rupture, and 7 cases of tibial tuberosity attachment rupture. Preoperative Caton-Deschamps index was 1.47±0.13. RESULTS: All patients were followed up 12-30 months (mean, 20.5 months). All incisions healed by first intention. And no complication such as infection, recurrent rupture, and neurovascular injury occurred. At 1 year after operation, the knee range of motion was (131.0±10.2)°, Lysholm score was 87.4±2.4, Kujala score was 88.3±4.8, the thigh circumference which was measured at 10 cm above the upper end of the patella was (42.58±1.93) cm; all showing significant differences when compared with preoperative values ( P<0.05). The effectiveness results were excellent in 9 cases and good in 3 cases according to the Insall evaluation criteria. The Caton-Deschamps index was 1.09±0.11, which was significantly lower than preoperative one ( t=8.155, P=0.000). CONCLUSION: Patellar tendon reconstruction with LARS artificial ligament is an effective method for the old patellar ligament rupture, which can effectively repair the knee extension device and restore knee function.

Underhang of the tibial component increases tibial bone resorption after total knee arthroplasty.

PURPOSE: One of the causes of aseptic loosening is marked tibial bone resorption (TR) at the tibial bone-component interface after total knee arthroplasty (TKA). It was hypothesized that insufficient coverage of the tibial component and improper cementing technique would cause increased TR after cemented TKA. METHODS: One hundred thirty-four primary TKAs in 107 patients with varus osteoarthritis were included in this study. The relationships between the TRs at 2 years after TKA and the tibial component underhang (TUH), the thickness of the cement mantle around the keel, and clinical parameters were evaluated. RESULTS: The widths of TRs on anteroposterior radiographs were significantly larger on the medial side than on the lateral side (p = 0.001), whereas the difference between the anterior and posterior sides on lateral radiographs was relatively small. Multiple regression analyses showed that medial TR was positively related to medial TUH (p = 0.006), and lateral TR was positively related to a thicker distal cement mantle (p = 0.027). On the lateral view, stepwise selection indicated that postoperative knee flexion angle was the most significant risk factor (p = 0.005) for anterior TR, and posterior TUH was the strongest predictor (p = 0.001) of posterior TR. CONCLUSIONS: To avert postoperative progressive TR, surgeons should perfectly fit a suitably sized tibial component to the medial edge of the tibia. Also, care should be taken to avoid an excessive cement mantle at the distal portion of the keel during TKA. LEVEL OF EVIDENCE: IV.

MiR-338-5p Promotes Inflammatory Response of Fibroblast-Like Synoviocytes in Rheumatoid Arthritis via Targeting SPRY1.

Our purpose is to study the roles of microRNA-338-5p (miR-338-5p) on the proliferation, invasion, and inflammatory response of fibroblast-like synoviocytes (SFs) in rheumatoid arthritis patients by regulating SPRY1. The target relationship between miR-338-5p and SPRY1 was validated through luciferase reporter system. The expression of miR-338-5p and SPRY1 in synovial tissues and synovial cells were detected using RT-PCR and western blot. The mimics and inhibitors of miR-338-5p were transfected into SFs. MTT, Transwell, and ELISA assays were used to analyze cell proliferation, invasiveness, and the secreted extracellular pro-inflammatory cytokines (such as IL-1a, IL-6, COX2) levels of SFs. MiR-338-5p was highly expressed in rheumatoid arthritis tissues and cells, and directly down-regulated the expression of SPRY1 in the SFs of rheumatoid arthritis patients. Cell proliferation, invasiveness and the expression level of pro-inflammatory cytokines in synovial cells increased after the transfection of miR-338-5p mimics, while the proliferation, invasion and expression level of pro-inflammatory cytokines decreased after the transfection of miR-338-5p inhibitors. In conclusion,miR-338-5p promoted the proliferation, invasion and inflammatory reaction in SFs of rheumatoid arthritis by directly down-regulating SPRY1 expression. J. Cell. Biochem. 118: 2295-2301, 2017. © 2017 Wiley Periodicals, Inc.

[HEMIARTHROPLASTY COMBINED WITH GREATER TROCHANTER REATTACHMENT DEVICE FOR TREATING INTERTROCHANTERIC FRACTURES IN ELDERLY PATIENTS].

OBJECTIVE: To evaluate the effectiveness of hemiarthroplasty combined with greater trochanter reattachment device for intertrochanteric fractures in elderly patients. METHODS: A retrospective analysis was made on the clinical data of 34 patients (35 hips) with intertrochanteric fractures underwent hemiarthroplasty combined with greater trochanter reattachment device between February 2010 and April 2013. Of 34 patients, 16 were males (16 hips) and 18 were females (19 hips), and the mean age was 85.6 years (range, 77-95 years). All fractures were caused by falling. The left hip was involved in 20 cases, the right hip in 13 cases, and the bilateral hips in 1 case. There were 33 cases (34 hips) of fresh fracture, and 1 case (1 hip) of old fracture. Fractures were rated as type III in 6 cases (6 hips), type IV in 11 cases (11 hips), and type V in 17 cases (18 hips) according to Evans-Jensen standard. All of the patients had different degree of osteoporosis and internal diseases. RESULTS: All patients underwent surgery successfully. The operation time was 70-90 minutes (mean, 76.6 minutes); the intraoperative blood loss was 260-400 mL (mean, 301.5 mL); the postoperative drainage was 80-530 mL (mean, 290.6 mL); and the hospitalization time was 10-12 days (mean, 11.7 days). Postoperative infection of incision occurred in 1 case, which was cured after dressing; primary healing of incision was obtained in the other patients. No lower extremity deep vein thrombosis or other complications was observed. Twenty-six cases (27 hips) were followed up 12-48 months (mean, 21.3 months). X-ray examination showed fracture healing, and the healing time was 2.5-3.5 months (mean, 2.8 months). There was no dislocation, prosthesis loosening, dislocation, loosening of titanium cable, periprosthetic osteolysis, or other complications during the follow-up period. According to Harris hip score, the results were excellent in 8 hips, good in 15 hips, fair in 4 hips, and the excellent and good rate was 85.2% at 1 year after operation. CONCLUSION: The hemiarthroplasty combined with greater trochanter reattachment device is a feasible and effective method to treat intertrochanteric fractures in the elderly patients. It can allow early ambulation and improve quality of life, but it is necessary to strictly control the indications, and perioperative management should be paid attention.