Effect of limb rotation on radiographic alignment in total knee arthroplasties

Abstract

Limb rotation had a highly statistically significant effect on measured anatomic alignment and mechanical angles. A correlation between limb rotation, anatomic mechanical angle, mechanical angles measured at femur and tibia and the femoral component distance ratio was established. As the anatomic mechanical angle and the femoral component distance ratio change linearly in the range of 20 degrees internal and external limb rotation, a calculation of the femoral component distance ratio could be used to re-calculate the limb rotation at the time of radiographic assessment to evaluate the evidence of a long leg radiograph.

Effect of Limb Rotation on Radiographic Measurements of Carpal Parameters in the Equine Carpus

“…For example, Major et al, (1996) and Yoon et al, (2002) identified the effect of head orientation on cephalometric measurements in posteroanterior radiographs in humans. Also, Lonner et al, (1996) and Radtke et al, (2010) investigated the effect of limb rotation on the radiographic alignment of total knee arthroplasties on synthetic femur and tibia (Sawbones) for human study purposes. These studies identified an acceptable range of object rotation through which the parameters did not demonstrate significant errors.…”

“…These studies identified an acceptable range of object rotation through which the parameters did not demonstrate significant errors. Furthermore, some of the studies included equations to recalculate measurements on the rotated radiographs in order to reduce the requirement to repeat radiographs (Radtke et al, 2010). In equine carpal radiography, a few parameters were established using DP views by a number of authors such as Fretz (1980), Pharr and Fretz (1981), Auer et al, (1982) and Bertone et al, (1985).…”

Assessment of two-dimensional (2D) and three-dimensional (3D) lower limb measurements in adults: Comparison of micro-dose and low-dose biplanar radiographs

“…Therefore, 2D and 3D measurements on biplanar radiographs (BPR) in a weight-bearing position are well established for evaluation of degenerative, traumatic, or developmental anomalies of the lower limbs. They are part of the preoperative planning and postoperative assessment of derotational osteotomies, total knee or hip replacement, and for documentation of treatment success [6][7][8]. Preoperative assessment of lower leg length is especially important in patients undergoing total hip arthroplasty (THA), since leg length discrepancy following total hip arthroplasty is a leading cause of patient dissatisfaction, and should be corrected for a better clinical outcome after THA [9].…”

Evaluation of the 3-Dimensional, Weight-Bearing Orientation of the Normal Adult Knee

“…Furthermore, while the importance of obtaining full-length, standing radiographs in assessing coronal alignment has previously been emphasized, (18, 19), two-dimensional (2D), plain radiography is also limited. Rotational attitudes due to the degree of deformity or anatomic variations such as femoral bowing, can affect standard measurements of limb alignment on 2D images (20, 21). While computed tomography (CT) scans allow 3D adjustments for limb rotation, they are obtained without weight-bearing, are time consuming, and impractical to routinely apply to clinical practice due to the high level of radiation exposure (22).…”