RESUMEN
BACKGROUND:Osteoporosis is a common comorbidity in patients with knee osteoarthritis.The impact of osteoporosis on the prognosis of unicompartmental knee arthroplasty is a trending topic of current research. OBJECTIVE:To investigate the effect of different bone densities on the stress value and stress distribution of each structure in the joint after unicompartmental knee arthroplasty using finite element analysis,and to evaluate the correlation between osteoporosis and complications. METHODS:CT and MRI were adopted to obtain the lower limb image data of a volunteer.Geomagic Studio,Ansys workbench,and Mimics were used to establish a finite element model of the knee joint with normal sclerotin condition(T-value≥-1.0).The finite element model of the knee joint with osteopenia(-2.5<T-value<-1.0)and osteoporosis(T-value≤-2.5)was established by changing the elastic modulus,and the validity was verified.The Boolean operation was used to simulate unicompartmental knee arthroplasty,and the unicompartmental knee arthroplasty models of three groups of sclerotin conditions were established.A 1 000 N vertical downward load was applied to the center of the femoral condyle of the three models.The stress data of the meniscus,the tibial cartilage,the polyethylene liner surface,and the surfaces of the cortical bone and the cancellous bone under the tibial prostheses,as well as the strain data of the polyethylene liner and the cancellous bone under tibial prostheses,were also observed and compared. RESULTS AND CONCLUSION:(1)Compared with the normal sclerotin group and the osteopenia group,the peak stress of the meniscus and the polyethylene liner surface was larger,and the peak stress of the tibial cartilage was smaller in the osteoporosis group.(2)In the three models,the high-stress value of the cortical bone under the tibial prostheses increased with osteopenia,and the stress was concentrated on the internal edge of the cortical bone.The high-stress value of the cancellous bone under the tibial prostheses decreased with osteopenia,and the stress was concentrated on the posteromedial side of the cancellous bone and the curved bottom of the keel groove.(3)The strain data on the polyethylene liner and cancellous bone under tibial prostheses in the osteoporosis group were greater than those in the normal sclerotin and osteopenia groups.(4)Osteoporosis can cause biomechanical abnormalities of the internal structure of the knee joint after the treatment of unicompartmental knee arthroplasty,which may increase the incidence of complications and the risk of re-surgery.
RESUMEN
OBJECTIVE@#To investigate the effect of Kartogenin (KGN) combined with adipose-derived stem cells (ADSCs) on tendon-bone healing after anterior cruciate ligament (ACL) reconstruction in rabbits.@*METHODS@#After the primary ADSCs were cultured by passaging, the 3rd generation cells were cultured with 10 μmol/L KGN solution for 72 hours. The supernatant of KGN-ADSCs was harvested and mixed with fibrin glue at a ratio of 1∶1; the 3rd generation ADSCs were mixed with fibrin glue as a control. Eighty adult New Zealand white rabbits were taken and randomly divided into 4 groups: saline group (group A), ADSCs group (group B), KGN-ADSCs group (group C), and sham-operated group (group D). After the ACL reconstruction model was prepared in groups A-C, the saline, the mixture of ADSCs and fibrin glue, and the mixture of supernatant of KGN-ADSCs and fibrin glue were injected into the tendon-bone interface and tendon gap, respectively. ACL was only exposed without other treatment in group D. The general conditions of the animals were observed after operation. At 6 and 12 weeks, the tendon-bone interface tissues and ACL specimens were taken and the tendon-bone healing was observed by HE staining, c-Jun N-terminal kinase (JNK) immunohistochemical staining, and TUNEL apoptosis assay. The fibroblasts were counted, and the positive expression rate of JNK protein and apoptosis index (AI) were measured. At the same time point, the tensile strength test was performed to measure the maximum load and the maximum tensile distance to observe the biomechanical properties.@*RESULTS@#Twenty-eight rabbits were excluded from the study due to incision infection or death, and finally 12, 12, 12, and 16 rabbits in groups A-D were included in the study, respectively. After operation, the tendon-bone interface of groups A and B healed poorly, while group C healed well. At 6 and 12 weeks, the number of fibroblasts and positive expression rate of JNK protein in group C were significantly higher than those of groups A, B, and D (P<0.05). Compared with 6 weeks, the number of fibroblasts gradually decreased and the positive expression rate of JNK protein and AI decreased in group C at 12 weeks after operation, with significant differences (P<0.05). Biomechanical tests showed that the maximum loads at 6 and 12 weeks after operation in group C were higher than in groups A and B, but lower than those in group D, while the maximum tensile distance results were opposite, but the differences between groups were significant (P<0.05).@*CONCLUSION@#After ACL reconstruction, local injection of a mixture of KGN-ADSCs and fibrin glue can promote the tendon-bone healing and enhance the mechanical strength and tensile resistance of the tendon-bone interface.