No abstract

INTRODUCTIONTotal knee arthroplasty (TKA) has been established as a surgical method for treatment of osteoarthritis of the knee. Previous studies with long-term follow-up have demonstrated that 80% of patients who undergo TKA are satisfied with the results [2,3]. Such studies consistently showed that the mechanical axis and ligament balance are important factors to consider for obtaining good clinical results.The postoperative mechanical axis in TKA is usually within ±3° of the planned axis, and deviation from this can lead to early loosening [4][5][6][7]. A postoperative mechanical axis within ±3° after TKA was noted in 74% of patients (37 of 50) in a study by Petersen and Engh [8], and 75% (469 of 637) in a study by Mahaluxmivara et al. [9]. Varus/valgus placement of the femoral and tibial components can similarly lead to loosening [10]. A change in the joint line affects the range of motion [11], as does retroversion of the tibial component [12,13].Navigation systems have been developed to obtain a more accurate grasp of the mechanical axis and aid in placement of the components in TKA. Mielke et al. Kurume Medical Journal, 58, 21-26, 2011 Summary: For successful total knee arthroplasty (TKA), it is very important to gain an accurate grasp of the mechanical axis of the lower limb and establish a suitable ligament balance. Recently, TKA using navigation systems has been developed to accomplish more accurate component placement and to achieve a better understanding of the mechanical axis. The purpose of this study was to compare the radiological results of computer-navigated TKA with those of conventional TKA. We prospectively evaluated 75 primary TKAs (75 subjects) that were performed using a cruciate-retaining prosthesis of the same model at our institution. The subjects were allocated alternately to a navigation group (37 knees) and a conventional group (38 knees). Postoperative radiographs were taken in the standing position at 12 weeks after surgery, and were evaluated in accordance with the report of Bäthis et al. [1]. No significant difference in preoperative profiles was observed between the two groups. At the postoperative radiographic evaluation, significantly better results were obtained in the navigation group with regard to the mechanical axis and the component, but the results were less conclusive in the lateral femoral component position. Our findings suggest that computer-navigated TKA is useful for obtaining more accurate results. However, the present study was limited by the small number of subjects and short follow-up period, and therefore further study involving more subjects and a longer-term follow-up will be needed.Key words computer-assisted total knee arthroplasty, cruciate-retaining prosthesis, radiographic evaluation, mechanical axis, alignment of the component

No abstract

No abstract

No abstract