Factors Affecting Tibial Tuberosity-Trochlear Groove Distance in Recurrent Patellar Dislocation

Area of Science:

• Orthopedic surgery
• Biomechanics
• Radiology

Background:

• The tibial tuberosity-trochlear groove (TT-TG) distance is a key metric for determining the need for tibial tubercle osteotomy.
• Understanding factors influencing TT-TG distance is vital for optimizing surgical interventions in patellofemoral instability.

Purpose of the Study:

• To evaluate the impact of tibial tuberosity lateralization, trochlear groove medialization, and knee rotation angle on TT-TG distance.
• To scrutinize the rationale for tibial tubercle transfer based on TT-TG distance in normal and patellar dislocated knees.

Main Methods:

• Retrospective analysis of rotational profile computed tomography scans in patellar dislocation and control groups.
• Assessment of femoral anteversion, tibial torsion, knee rotation angle, tuberosity lateralization, and trochlear groove medialization.
• Investigation of the relationship between these parameters and TT-TG distance.

Main Results:

• Patellar dislocation group exhibited significantly increased TT-TG distance (19.05 mm vs. 9.02 mm) compared to controls.
• Greater tuberosity lateralization (64.1% vs. 60.7%) and tibial external rotation (7.9° vs. -0.81°) were observed in the dislocation group.

Conclusions:

• Tuberosity lateralization and knee rotation are significant factors contributing to patellar dislocation.
• These factors, alongside TT-TG distance, should be considered when deciding on tibial tubercle osteotomy for patellar dislocation.