Distal femur rotational alignment and patellar subluxation: A CT scan in vivo assessment

Abstract

Prospective diagnostic study.

Tibial Tubercle to Trochlear Groove Distance Measured by Posterior Condylar Reference Line on MRI Can Over-Evaluate Lateralization Deformity of Tibial Tubercle in Patients with Recurrent Patellar Dislocation

“…Yang et al [ 18 ] suggested that the dysplastic distal femoral condyle was composed of anterior and posterior femoral condylar dysplasia. In accordance with previous studies on CT images [ 17 , 20 , 22 ], the results of our study by MRI showed that patients with PD was in the presence of posterior femoral condylar dysplasia: longer medial and shorter lateral posterior condyle, and larger PCA. Previous studies focused on identifying a reference point that could avoid the influence of the femoral trochlea on assessing the lateralization of the tibial tubercle in patients with trochlear dysplasia, such as the TT-PCL distance and TT-RA distance [ 15 , 16 ], while ignoring the PCRL—the reference line in most measurements—may be affected by posterior femoral condylar morphology (the posterior condylar dysplasia could make the PCRL more internal rotation).…”

“…The transepicondylar axis has been proven to be a reliable and constant reference line on the distal femoral condyles [ 19 ], consisting of anatomical and surgical transepicondylar axis (AEA and SEA, respectively). Both of them have been poorly studied in patients with PD [ 17 , 20 , 21 , 22 , 23 ]. We first proposed to measure the TT-TG distance using AEA and SEA as reference lines on axial MRI slices (TT-TGa and TT-TGs, respectively), which were theoretically independent of posterior femoral condylar dysplasia.…”

Articular cartilage of the posterior condyle can affect rotational alignment in total knee arthroplasty

“…Rotational malalignment of the femoral components can cause patellofemoral complications such as patellar subluxation and late patellar prosthesis failure [1,2,5,21]. Ligament balance abnormalities can lead to knee instability and lift-off in weight-bearing activities [16,29].…”

Contemporary femoral designs in total knee arthroplasty: effects on the patello-femoral congruence

“…Maltracking may result from excessive or unbalanced tension in the surrounding soft tissues during knee flexion, so our radiographic measurements do not reflect patello-femoral congruence during ROM. A CT scan or MRI in vivo assessment might be necessary [18,40,41]. Anyway, Varadarajan et al [42] demonstrated that, even with a correct external rotation, the trochlear groove in current TKA designs only partially restores normal anatomy.…”