Patellar dislocation is associated with increased tibial but not femoral rotational asymmetry

Abstract

PurposePatellar dislocation is associated with a range of anatomical abnormalities affecting the trochlea, extensor mechanism and the tibia. The relationship between patellofemoral instability and rotational abnormalities of the posterior condyles, trochlear groove and proximal tibia has not been adequately determined. This study aimed to identify the frequency and severity of anatomical risk factors to determine their relative contribution to patellofemoral instability. MethodsA retrospective morphological study was undertaken comparing multiple anatomical measurements with magnetic resonance imaging of 50 patients with patellofemoral instability to an age‐ and gender‐matched Control group (n = 50). Several techniques were assessed measuring both femoral and tibial axial asymmetry. A new measurement, tibial rotational asymmetry, comparing a line between the midpoints of the collateral ligaments to the axis between the patellar tendon and posterior cruciate ligament, was assessed for its association with patellofemoral instability. ResultsCompared to the controls, the patellofemoral instability group demonstrated a significant difference in tibial rotational asymmetry, with a mean of 2.9° (SD 3.2°) externally rotated vs − 1.6° (SD 2.2°) in the control group. Significant differences were also demonstrated regarding the sulcus angle, tibial tubercle–trochlear groove distance, tibial tubercle–posterior cruciate ligament distance, patellar size and the Insall–Salvati ratio. There were no differences between groups regarding the lengths of the posterior condyles, the heights of the trochlear ridges or lateralisation of the trochlear groove. Further analysis of the patellofemoral instability group revealed a subgroup of males with normal anatomy (7/50) and a subgroup of females with isolated patella alta (7/50). ConclusionPatellofemoral instability is associated with tibial rotational asymmetry due to lateralisation of the tibial tubercle. It is also associated with patella alta and reduced trochlear groove depth. The femoral axial shape is otherwise unchanged. Level of evidenceIII.

Determination of Standard Values for Knee Version in a Healthy Population

“…However, because hypoplasia of the femoral condyles and tibial torsional asymmetry of the tibial plateau have also been discussed as causative factors for anterior knee pain, we tried to identify other measurement methods of intra-articular knee rotation to define different landmarks and lines for comparison with patients with knee disorders. 14,15 Thus, the FEL and TECL were examined in relation to each other and to the DFC and DTH.…”

“…However, because hypoplasia of the femoral condyles and tibial torsional asymmetry of the tibial plateau have also been discussed as causative factors for anterior knee pain, we tried to identify other measurement methods of intra-articular knee rotation to define different landmarks and lines for comparison with patients with knee disorders. 14,15 Thus, the FEL and TECL were examined in relation to each other and to the DFC and DTH. Tomczak et al 33 compared femoral torsional measurements using the method of Waidelich and Strecker in 44 patients and showed that there was no significant difference between MRI and computed tomography (CT) measurements.…”

“…16,18,26 At the proximal tibia, the angle between the DTH and TECL was -2.7°6 2.3°. Geraghty et al 14 described a significant difference in tibial rotational asymmetry in patients with patellofemoral instability compared with healthy controls on knee MRI. However, there have been no previous descriptions of the angle between the DTH and TECL in the literature.…”

Femoral Anteversion Measured by the Surgical Transepicondylar Axis Is Correlated with the Tibial Tubercle–Roman Arch Distance in Patients with Lateral Patellar Dislocation

“…First, not all segmental femoral torsion parameters were analyzed, such as neck and mid femoral anteversion. Second, the tibial morphology was not included, which has been demonstrated to be associated with LPD [ 35 ]. Third, measurements by MRI were not performed.…”

A Scientometric Analysis of Studies on Patellar Dislocation

“…Soft tissue structural abnormalities include contracture of the lateral retinaculum, laxity of the medial retinaculum, and injury or rupture of the medial patellofemoral ligament (MPFL); bony structural abnormalities include trochlear dysplasia, tibial external rotation, increased femoral anteversion, lateralization of the tibial tuberosity, and patella alta. 16,26,32,53,64 Nonoperative treatment has long been considered the standard of care, 4,6 whereas operation is now recommended for recurrent patellar dislocations, for osteochondral fractures with free bodies, and for those whose nonoperative interventions have failed. 63 Scientometric analysis is a tool for mapping identified publication records and enabling the study of mathematical patterns in the literature, and it is a method for assessing and predicting research trends in specific fields.…”