Tibial tubercle torsion, a new factor of patellar instability

• Published in: Orthopaedics & traumatology, surgery & research surgery & research, 2017-12, Vol.103 (8), p.1173-1178
• Main Authors: Chassaing, V., Zeitoun, J.-M., Camara, M., Blin, J.-L., Marque, S., Chancelier, M.-D.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Case-Control Studies; Female; Humans; Joint Instability - diagnostic imaging; Magnetic Resonance Imaging; Male; Middle Aged; Patellar dislocation; Patellar Dislocation - diagnostic imaging; Patellar instability; Patellofemoral Joint - diagnostic imaging; Rotation; Tibia - diagnostic imaging; Tibial tubercle position; Tibial tubercle torsion; Tibial tubercle-trochlear groove distance; Young Adult
• ISSN: 1877-0568; 1877-0568
• DOI: 10.1016/j.otsr.2017.07.019

External torsion of the anterior tibial tubercle (TT), defined as external rotation around a craniocaudal axis with respect to the posterior femoral condylar plane, may induce patellar instability. To our knowledge no studies have focused on this parameter. The present study aimed to perform an MRI analysis of TT torsion. The study hypothesis was that TT torsion correlates with patellar instability and with 3 of its components: tibial tubercle-trochlear groove (TT-TG) distance, axial engagement index of the patella (AEI), and patellar tilt. Four observers performed MRI measurements for 2 groups: 37 patellar instability patients (PI group) with history of at least 2 patellar dislocations, and 50 control patients with meniscal lesion but free from patellofemoral pathology. All measurements were taken from 2 axial slices with the posterior condylar plane as reference. The intra-class correlation coefficient (ICC) was 0.88. TT torsion correlated with patellar instability, with a mean 5.8̊ in controls and 17.9̊ in the PI group (P