BACKGROUND:The safety and efficacy of simultaneous bilateral total knee replacement or selective unilateral total knee arthroplasty in patients with severe osteoarthritis of the knees are stil controversial. OBJECTIVE:To compare safety and clinical efficacy of patients with osteoarthritis knees after simultaneous bilateral total knee replacement or selective unilateral total knee replacement. METHODS:Total y 60 cases with severe osteoarthritis of the knees (90 knees) undergoing total knee replacement were divided into unilateral total knee replacement group (n=30, 30 knees), and the simultaneous bilateral total knee replacement group (n=30, 60 knees). RESULTS AND CONCLUSION:There was no significant difference in the incidence of other complications such as infection, mortality, pulmonary embolism in patients of both groups (P>0.05). The incidence of cardiovascular complications, postoperative blood loss and blood transfusion were higher in the bilateral knee group than in the unilateral knee group (P<0.05). During fol ow-up at 1 year after replacement, no significant differences in range of motion, muscle strength of quadriceps and hospital for special surgery knee score were detected in patients of both groups (P>0.05). However, Visual Analogue Scale scores were significantly lower in the bilateral knee group than in the unilateral group (P<0.05). These data indicated that the risk of cardiovascular complications was high in patients receiving bilateral total knee replacement. Patients with severe cardiovascular disease should avoid simultaneous bilateral total knee arthroplasty.

BACKGROUND:Titanium and titanium aloy are used mostly in artificial joints, fracture fixation, and oral transplantation, while there are complex cases of insufficient bone mass in these areas. The deepened research of stem cels offers a solution for bone injury to promote new bone formation. The biocompatibility of titanium and stem cels and optimization of titanium surface modification have aroused people's attention. OBJECTIVE:To investigate whether the biocompatibility of titanium and human adipose-derived mesenchymal stem cels can be improved by type I colagen modification of titanium sheets. METHODS:The experiment was divided into two groups. Modification group: titanium sheet was modified with type I colagen; control group: titanium sheet was not modified with type I colagen. Human adipose-derived mesenchymal stem cels at passage 6 were implanted into titanium sheet in two groups. Then we calculated the number of adherent cels in two groups at 1, 2 and 4 hours after implantation, and compared the celladhesion rate. MTT assay was used to observe the proliferation of cels on titanium sheet at 2, 4, 6 and 8 days after implantation. DNA and protein content of cels were detected at 3, 6, 9 days after implantation. The growth of human adipose-derived mesenchymal stem cels seeded upon the titanium sheets was observed under scanning electron microscope at 6 days. RESULTS AND CONCLUSION:When the cels were cultured for 1 hour and 2 hours, the number of adherent cels in the modification group was higher than in the control group (P < 0.05). The absorbance of cels in two groups was increased as the culture time, as detected by MTT assay. The modification group had a significantly higher absorbance value than the control group at 4, 6, 8 days (P < 0.05). DNA and protein contents of the cels in the modification group were higher than that in control group at 6 and 9 days (P < 0.05). At 6 days, the number of adherent cels and secretion of adherent stromal cellmatrix in the modification group were significantly better than that in control group, observed by scanning electron microscopy. Type I colagen modified titanium sheets have good surface activity and biocompatibility, and can promote the proliferation of human adipose-derived mesenchymal stem cels.