The EKA Femoral Rotation Focus Group has not identified a single best reference method to determine femoral component rotation , but surgeons mostly prefer the measured resection technique using at least two l and marks for cross-checking the rotation .
Malrotation of the femoral component after primary total knee arthroplasty ( TKA ) is one of the most important problems leading to painful TKA requiring revision surgery .
A comprehensive systematic review of the literature was performed to present current evidence on how to optimally place the femoral component in TKA .
Is radiographic measurement of distal femoral torsion reliable?
BACKGROUND Distal femur torsion ( DFT ) is a crucial parameter in knee replacement surgery . The reference st and ard for measuring DFT is posterior condylar angle ( PCA ) measurement using computed tomography ( CT ) . The objective of this study was to assess the feasibility and reliability of a radiographic PCA measurement method . MATERIAL S AND METHODS We studied 125 osteoarthritic knees in 79 patients ( 42 women and 37 men ) with a mean age of 71.6 ± 8.8 years ( range 47 to 86 years ) ; 32 knees were aligned , 85 in varus , and eight in valgus .  DFT was measured on an antero-posterior ( AP ) radiograph of the knee in 90 ° of flexion ( known as the seated AP view ) . The PCA was defined as the angle subtended by the tangent to the posterior condyles and the transepicondylar axis ( anatomic PCA [ aPCA ] ) or the line connecting the lateral epicondyle to the medial sulcus ( surgical PCA [ sPCA ] ) . The PCA was conventionally recorded as positive in the event of external torsion and negative in the event of internal torsion . PCA measurements were performed three times by each of five observers to allow assessment s of inter-observer and test-retest reliabilities . RESULTS aPCA was consistently negative ( mean , -6.1 ± 1.6 ° ) ( range , 0 to -10 ° ) ; inter-observer and test-retest reliability were satisfactory ( 0.54<rw 0.80 ) . sPCA was positive in 41 knees and negative in 84 knees ) ( mean , -0.3 ± 1.4 ° ) ( range , -5 ° to + 2 ° ) ; inter-observer and test-retest reliabilities were poor ( 0.28<r<0.69 ) . A weak but significant correlation was found between aPCA and coronal alignment , with a trend towards greater internal torsion in the group of valgus knees . CONCLUSION Radiographic measurement of DFT is simple and non-invasive . Measurement reproducibility was satisfactory for aPCA but not for sPCA . aPCA showed marked inter-individual variability and tended to increase when the knee was in valgus . Mean aPCA values were comparable to those reported using CT . In contrast to CT , radiographic DFT measurement can easily be incorporated into the pre- and postoperative work-ups for knee replacement surgery , provided the patient can achieve 90 ° of knee flexion . LEVEL OF EVIDENCE Level IV , prospect i ve cohort study
The EKA Femoral Rotation Focus Group has not identified a single best reference method to determine femoral component rotation , but surgeons mostly prefer the measured resection technique using at least two l and marks for cross-checking the rotation .
Malrotation of the femoral component after primary total knee arthroplasty ( TKA ) is one of the most important problems leading to painful TKA requiring revision surgery .
A comprehensive systematic review of the literature was performed to present current evidence on how to optimally place the femoral component in TKA .