Static patella tilt and axial engagement in knee extension are mainly influenced by knee torsion, the tibial tubercle–trochlear groove distance (TTTG), and trochlear dysplasia but not by femoral or tibial torsion

Abstract

Purpose The aim of this study was to investigate the association of femoral (FT), tibial (TT), and knee torsion (KT) on the patella tilt (PT), the axial engagement index (AEI), and the tibial tuberosity-trochlear groove distance (TTTG). Methods Femoral torsion, tibial torsion, knee torsion, patella tilt, the axial engagement index, the TTTG, and trochlear dysplasia were retrospectively evaluated on 59 patients suffering from recurrent patella instability or anterior knee pain with 118 torsional lower limb magnetic resonance imaging studies. Results FT and TT did not show any significant associations with TTTG, PT, and AEI (n.s.). KT was significantly associated with a higher TTTG, higher PT, and lower AEI (all, p < 0.001). Higher grade trochlear dysplasia was associated with a higher PT and lower AEI (both, p < 0.001). The Dejour classification showed no significant association with FT, TT, KT, and TTTG (n.s.). All measurement parameters showed an excellent interrater agreement (ICC 0.89-0.97). Conclusions Static patella tilt and patellofemoral axial engagement in knee extension are mainly influenced by knee torsion, TTTG, and trochlear dysplasia but not by femoral or tibial torsion. These findings help to understand the underlying reasons for the patella position in knee extensions in CT and MRI investigations in patients suffering from patella instability and patellofemoral pain syndrome. Level of evidence III.

Relationship between patellofemoral finite helical axis and femoral trans-epicondylar axis using a static magnetic resonance-based methodology

“…The variations in the FHA decreased in the middle stage, as a result of the femoral condyles enhancing patellar movement after it entered the trochlear groove [16]. Clinically, trochlear dysplasia is one of the common causes of patellar instability [17,18]. Some realignment surgeries, including sulcus-deepening trochleoplasty and plication of the medial retinaculum, have been performed for Fig.…”

Patellar Shape is Associated With Femoral Trochlear Morphology in Individuals with Mature Skeletal Development

“…Bony constraint is particularly important after the rst 20° of knee exion [2], while the patella begins to engage with the trochlea as the knee exes to 30°. Poor patellar and trochlear tracking can give rise to trochlear and/or patellar dysplasia [11,22]. In this report, we observed concurrent patellar and trochlear changes, possibly due to such patellar tracking during skeletal development.…”

“…A deep sulcus and a high lateral trochlea can help to maintain normal patella tracking [6], while abnormal tracking can mold patellar and trochlear morphology and impact patellofemoral joint instability [22]. Causes of trochlear dysplasia may include developmental factors or false patellar tracking during childhood [10,22]. Stabilization produces changes throughout the knee range of movement, including both bony and soft tissue constraints.…”

Patellar shape is associated with femoral trochlear morphology in individuals with mature skeletal development

“…Correct patellar tracking alters patellofemoral joint function and plays a key role in regulating knee joint stability. A deep sulcus and a high lateral trochlea can help to maintain normal patella tracking [ 6 ], while abnormal tracking can mold patellar and trochlear morphology and impact patellofemoral joint instability [ 22 ]. In the study of Otto et al [ 23 ], patients sufering from patellofemoral instability had a relatively larger lateral patellar facet, which was consistent with this study.…”