Polyvinyl alcohol (PVA) hydrogels are considered to be ideal materials for tissue engineering due to their high water content, low frictional behavior, and good biocompatibility. However, their limited mechanical properties restrict them from being applied when repairing load-bearing tissue. Inspired by the composition of mussels, we fabricated polyvinyl alcohol/hydroxyapatite/tannic acid (PVA/HA/TA) hydrogels through a facile freeze–thawing method. The resulting composite hydrogels exhibited high moisture content, porous structures, and good mechanical properties. The compressive strength and tensile strength of PVA hydrogels were improved from 0.77 ± 0.11 MPa and 0.08 ± 0.01 MPa to approximately 3.69 ± 0.41 MPa and 0.43 ± 0.01 MPa, respectively, for the PVA/HA/1.5TA hydrogel. The toughness and the compressive elastic modulus of PVA/HA/1.5TA hydrogel also attained 0.86 ± 0.02 MJm⁻³ and 0.11 ± 0.02 MPa, which was approximately 11 times and 5 times higher than the PVA hydrogel, respectively. The PVA/HA/1.5TA hydrogel also exhibited fatigue resistance abilities. The mechanical properties of the composite hydrogels were improved through the introduction of TA. Furthermore, in vitro PVA/HA/1.5TA hydrogel showed excellent cytocompatibility by promoting cell proliferation in vitro. Scanning electron microscopy analysis indicated that PVA/HA/1.5TA hydrogels provided favorable circumstances for cell adhesion. The aforementioned results also indicate that the composite hydrogels had potential applications in bone tissue engineering, and this study provides a facile method to improve the mechanical properties of PVA hydrogel.

Background: Several studies have compared robotics‐assisted (RA) and conventional manual (CM) approaches for total hip arthroplasty (THA), but their results are controversial.Methods: A literature search was conducted for controlled clinical trials (CCTs) comparing the clinical efficacy of the RA and CM approaches for THA and published between August 1998 and August 2018. The obtained data were analyzed using the statistical software Review Manager 5.3.Results: Fourteen articles were included in the meta‐analysis, which revealed that the RA group had less intraoperative complications, better cup angle, and more cases of cup placement in the safe zone than the CM group. However, the operation time required for the CM group was less than that required for the RA group. Moreover, postoperative complications (eg, dislocation and revision surgery) were less frequent in the CM group than in the RA group. However, the two groups had similar functional scores, total number of complications, and rate of occurrence of limb length discrepancy.Conclusion: Compared with the CM approach, the RA approach yields better radiological outcomes and fewer intraoperative complications in THA, but similar functional scores.

It has been noted that anterior cruciate ligament (ACL) injury-induced cartilage degeneration is the key risk factor for post-traumatic osteoarthritis (PTOA). However, whether the cartilage degeneration after ACL injury is caused by inflammation, abnormal biomechanics or both remains largely unknown, as there has been no animal model for separating the two factors so far. Eighteen-month-old female mini-pigs were divided into an "idealized" anterior cruciate ligament reconstruction (IACLR) group and a control group (n = 16 limbs per group). Real-time PCR, safranine O staining and indian ink staining were performed to verify whether animal models were successfully established or not. Multiple linear regression analysis was used to evaluate the correlation between levels of the inflammatory factors (including interferon [IFN]-γ, interleukin [IL]-1β, IL-4, IL-6, IL-8, IL-10, IL-12 and tumor necrosis factor [TNF]-α measured by the Luminex method) and changes in cartilage histology (quantified by morphological scoring) after surgery. A significant OA cartilage damage with increased MMP-1, MMP-13 mRNA levels and reduced aggrecan mRNA/protein levels was observed in IACLR groups. As a result, the IACLR gross morphology score was dramatically increased than control. Moreover, IACLR significantly increased the levels of IL-1β, IL-4, IL-6 and TNF-α in the synovial fluid of the knee. Most importantly, a close relationship was found between IL-1β, IL-6 and TNF-α concentrations and morphological score of PTOA, respectively. These results demonstrated that inflammatory factors are independently responsible for the onset of PTOA.

The purpose of this study was to evaluate the relationship between five previously established serum osteoarthritis biomarkers and the severity of cartilage lesions in the knee. Cartilage damage (classified according to the Outerbridge scoring system) and serum concentrations of cartilage oligomeric matrix protein (COMP), collagen type II C-telopeptide (CTX-II), matrix metalloproteinase-3 (MMP-3), collagen type III N-propeptide, (PIIINP), and hyaluronic acid (HA) were determined in 79 patients who underwent knee arthroscopy or total knee replacement. HA and COMP concentrations were significantly higher in the Outerbridge score 1 and 2 groups, respectively. These results suggest that serum COMP and HA concentrations can be used to predict early cartilage lesions in the knee.