Alignment in total knee arthroplasty

Abstract

Restoration of neutral alignment of the leg is an important factor affecting the long-term results of total knee arthroplasty (TKA). Recent developments in computer-assisted surgery have focused on systems for improving TKA. In a prospective study two groups of 80 patients undergoing TKA had operations using either a computer-assisted navigation system or a conventional technique. Alignment of the leg and the orientation of components were determined on post-operative long-leg coronal and lateral films. The mechanical axis of the leg was significantly better in the computer-assisted group (96%, within +/- 3 degrees varus/valgus) compared with the conventional group (78%, within +/- 3 degrees varus/valgus). The coronal alignment of the femoral component was also more accurate in the computer-assisted group. Computer-assisted TKA gives a better correction of alignment of the leg and orientation of the components compared with the conventional technique. Potential benefits in the long-term outcome and functional improvement require further investigation.

Stem abutment affects alignment of the humeral component in computer-assisted elbow arthroplasty

“…An overall error of no more than 2.0 is often considered the standard for most modern computerassisted systems, 1,10,17,34 and previous studies have reported alignment errors on the order of 2 to 3 at the hip 11,20 and knee. 3,23,32 In this study, implant alignment error for the reduced stem was 1.3 AE 0.5 mm and 1.2 AE 0.4 . This can be considered to be the accuracy of the computerassisted technique.…”

Time-Dependent Clinical Results of Rotating-Platform Total Knee Arthroplasty According to Mechanical Axis Deviation

“…Various ranges of acceptable limb alignment have been reported, but ±3° varus/valgus mechanical axis has been associated with higher success rates7,8). The postoperative limb alignment can be over ±3° varus/valgus in up to 30% of the cases after conventional TKAs9).…”

High flexion knee arthroplasty: the relationship between rotational angles and flexion angle after total knee arthroplasty

“…On the other hand, to gain high flexion angle after TKA, it is necessary to reduce implant malposition. The implant malposition with conventional instrumentation in TKA can be as high as 20 %–40 %, even in major arthroplasty centers, as reported in the literatures [4, 5]. To limit implant malposition, smart tools such as navigation or patient-specific instrumentation have been developed in TKA [6, 7].…”