Objective To evaluate the clinical results，imaging results and postoperative complications of cementfree prostheses for the treatment of secondary acetabular fractures，and to compare these differences between different coated prostheses.Methods A total of 65 patients who underwent total hip arthroplasty (THA) in the department of Osteonecrosis&Joint Reconstruction Surgery of Honghui hospital from January 2015 to January 2017 due to secondary lesions after acetabular fractures were retrospectively enrolled.39 males and 26 females were included，and the mean age was (46.5±18.6) years.Harris hip score (HHS)，visual analog scale (VAS)，12 item short form health survey(SF-12) and acetabular cup abduction angle were used to evaluate postoperative functional results and prosthesis stability.The intraoperative conditions (operation time，blood loss，blood transfusion rate)，followup outcomes (HHS，VAS，SF-12)，prosthesis survival rate and complications were compared between different coated prostheses.Results 65 patients were followed up (6.2±0.9)years.The results of the 1 year post operation and the last follow-up were significantly improved compared with the pre-operation，and the differences were statistically significant (P＜0.05).There was no significant difference in the abduction angle of acetabular cup at 1 year and last follow-up (P＞0.05).The tantalum coating group had shorter operation time，better HHS and lower revision rate at 1 year follow-up.Three patients underwent revision surgery due to aseptic loosening during follow-up.No complications such as deep vein thrombosis and sciatic nerve injury occurred in all patients.Conclusion In the treatment of postoperative lesions of acetabular fractures，cement-free total hip arthroplasty can achieve satisfactory long-term clinical results.Tantalum metal-coated prostheses have lower revision rates when selecting cement-free prostheses.

Objective To investigate the early effect of domestic robot-assisted total knee arthroplasty (RATKA) for knee osteoarthritis by a prospective randomized controlled trial.Methods The clinical data of 18 patients who underwent total knee arthroplasty (TKA) from August 2021 to January 2022 were collected.They were divided into traditional TKA group and RATKA group by random number table method，with 9 patients in each group.There were 3 males and 6 females in the traditional TKA group，with an average age of (70.00±10.63) years.And there were 3 males and 6 females in RATKA group，with an average age of (68.22±6.12) years.Operation time，intraoperative blood loss，postoperative days in hospital，postoperative hemoglobin (HB) and hematocrit (HCT) of the two groups were recorded.ROM，KSS score and WOMAC pain，stiffness，and functional scores were used to evaluate knee function and pain.X-rays of both lower limbs were taken to measure the degree of bias of HKA，lateral distal femoral angle (LDFA)，medial proximal tibial angle (MPTA) and joint line convergence angle (JLCA)，expecting to evaluate the lower limb alignment and implant position of prosthesis.Results The operations in both groups were successfully completed.All the incisions healed at stage I and no operative complications occurred.The operation time of the RATKA group was longer than that of the traditional TKA group (P＝0.002)，and there were no significant difference in intraoperative blood loss，postoperative drainage volume，postoperative HB and HCT reduction between the two groups (P＞0.05).After 5 months of follow-up，ROM and KSS scores of knee joint as well as WOMAC pain，stiffness，and functional scores were better in both groups compared with those before surgery.The differences were statistically significant (P＜0.05)，but there were no significant difference in the difference of the above indexes between the two groups (P＞0.05).The postoperative degree of bias of hip-knee-ankle angle of the RATKA group was significantly better than that of the traditional TKA group，with statistically significant difference (P＜0.05).There was no significant difference in postoperative LDFA and MPTA between the two groups (P＞0.05).JLCA in RATKA group was lower than that in traditional TKA group (P＜0.05) and it was closer to the ideal value in RATKA group.Conclusion TKA performed by domestic robot can improve the precision of placement of the prosthesis and the lower limb alignment，and achieve good short-term effectiveness.The long-term effectiveness remains to be further observed.

Objective To explore the biological effect of Dentin Matrix Protein-1 (DMP-1) on chondrocytes in osteoarthritis (OA).Methods The expression of DMP-1 in cartilage cells of OA rat model was analyzed with Affymetrix microarray.The chondrocyte was isolated，cultured and transfected with DMP-1 gene.Subsequently，the effect of DMP-1 on the proliferation of chondrocyte was examined with CCK-8 assay.ELISA assay was performed for detection of chondrocyte glycosaminoglycan (GAG) secretion and proinflammatory cytokines (IL-6 and TNF-α).The expression of Col2a1 was observed by immunofluorescence.RT-qPCR was to evaluate the expression levels of DMP-1，Sox9，Acan，and Col2a1 genes.Western Blot assay was conducted for DMP-1，Sox9，Acan，Col2a1 expressions.Flow cytometry and Calcein AM/PI staining assays were conducted for detection of the anti-apoptosis ability of chondrocyte treated with DMP-1.Results The Microarray analysis showed that the expression level of DMP-1 in OA group was lower than that in Control group in vivo (P＜0.05)；The expression level of DMP-1 in chondrocytes of OA group was also lower than that in Control group in vitro (P＜0.001).After transfection with DMP-1 gene，the expression level of DMP-1 in chondrocytes and chondrocytes induced by IL-1β was higher than that in the non-transfected group.The viability of chondrocytes induced by IL-1β was higher in transfected DMP-1 chondrocyte than that in the non-transfected group (P＜0.001).The expression of GAGs and immunofluorescence of Col2a1 in the transfected DMP-1 chondrocytes induced by IL-1β was significantly higher than that in the untransfected group，as well as the expression levels of Sox9，Acan and Col2a1 were significantly higher than that in the untransfected group (P＜0.001).The levels of IL-6 and TNF-α and apoptosis of transfected DMP-1 chondrocytes induced by IL-1β were significantly lower than those of non-transfected group (P＜0.001). Conclusion DMP-1 can be used to transfect chondrocytes and reduce the progression of OA.