Abstract
Background
A careful consideration of change of the rotational profiles of total limb after unilateral total knee arthroplasty is necessary. The aim of the present study was to evaluate the discrepancies of rotational profiles of total limb between operated and non-operated limb following unilateral total knee arthroplasty.
Methods
We conducted a retrospective analysis the CT data from 32 patients undergoing primary unilateral total knee arthroplasty using measured resection technique, which femur implant was applied at an external rotation of 3° relative to the posterior condylar axis from July 2009 to April 2013 in our hospital. Using these CT studies, rotational profiles of total limb such as femoral torsion angle (femoral neck anteversion angle; FTA), tibial torsion angle (TTA), neck-malleolar angle (NMA), knee joint rotation angle (rotational mismatch; KJRA) and total limb rotation (TLR) were measured.
Results
There were significant discrepancies of FTA and KJRA between operated and non-operated limb following unilateral total knee arthroplasty. The mean difference of operated and non-operated side for FTA and KJRA were −6.5 ± 11.9° (p=0.004) and −6.8 ± 5.0° (p < 0.001) respectively. However, there were no significant discrepancies of TLR, TTA and NMA.
Conclusion
With comparison with non-operated side, although FTA is significantly decreased in operated limb than non-operated limb following total knee arthroplasty, there were no significant discrepancies of NMA and TLR, because of the compensatory effect of KJRA. However, excessive external rotation of femur implant can affect adversely on rotational profiles of total limb. Further long term studies will be required to evaluate the change of the rotational profiles following unilateral total knee arthroplasty.
