| Objective:To discuss clinical results of GeminiⅡrotating-platform total knee arthroplasty,and assess the safety and validity of it.Methods:From March 2004 to May 2007,52 patients(70 knee) received GeminiⅡrotating-platform total knee arthroplasty.There were 12 males and 40 females at average age of 62 years(39-79 years).The left joints were involved in 28 cases and right joint in 42 cases.There were 37 cases of osteoarthritis,15 cases of rheumatoid arthritis.All patients received primary total knee arthroplasty.50 of the knees were varusly deformed,9 were valgusly deformed, and 11 with normal alignment.The outcomes were evaluated according to HSS(the hospital for special surgery) scoring system,the scores of preoperation for HSS,pain,function,ROM,muscle strength,flexion deformity and stability of knee were 49.4±12.7,6.9±3.8,8.7±1.3,8.1±2.9,7.9±1.2,7.6±1.8,7.8±1.4.Preoperative and postoperative radiographs including a standing anteroposterior view,a lateral view,and a skyline view of the patella were obtained with all patients,and radiographs would be done every 6 to 12 months after the operation.The radiographs were examined for the location of the prosthesis,radiolucency around the femoral and tibial components,and the mechanical axis of the limb was measured.It was diagnosed as prosthesis loosening if progressive bone-cement radiolucencies exceed 2 mm,or with tibial component subsidence,or the mechanical axis of the leg altered.The location of the patella was evaluated by a skyline view of it.Clinical effect were evaluated according to the scores of HSS,single item and their improvement rate,image analysis,and postoperative complications as well. Statistical comparisons of both preoperative scores and the final follow up scores were performed using paired t-test at a 0.05 level of significance.Results:All patients were followed up from 6 months to 3 years with an average of 24.7 months.At the last follow up,the scores for HSS,pain, function,ROM,muscle strength,flexion deformity and stability of knee were 94.2±13.1,26.8±6.5,20.1±4.1,13.6±1.8,9.3±0.8,9.5±0.7,9.4±0.3.They were improved compared with the preoperation date to some extents and there was significant difference between them(p＜0.05).Image analysis showed that all implants were in satisfactory position,and there were no prosthesis loosening or radiolucent lines or patella dislocation.There were 3 case complicated with deep vein thrombosis of lower extremity,this was cured by thrombolysis treatment.There was no pulmonary embolism,deep infection and dislocation.Conclusion:The design of GeminiⅡrotating-platform prosthesis is scientific and proper.GeminiⅡprosthesis with higher stability and better range of motion approximated the natural kinematics of the knee more closely,which is able to minimise contact stresses and lessen polyethylene wear markedly. Short term follow-up shows good clinical results,but long term effect still need further follow up studies.Reestablishing a neutral mechanical axis of the limb, cutting bone correctly,exactitude technique of proper balancing of the soft tissues in both flexion and extension,correct treatment in perioperation,and preventing postoperative complications are key point to good clinical effect and excellent longevity.
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