Anatomical Characteristics Contributing to Patellar Dislocations Following MPFL Reconstruction: A Dynamic Simulation...

Area of Science:

• Orthopedics
• Biomechanics
• Sports Medicine

Background:

• Patellar instability is a common complication following medial patellofemoral ligament (MPFL) reconstruction.
• Pathologic anatomical factors are implicated in recurrent patellar dislocations.
• Understanding these factors is crucial for improving surgical outcomes.

Purpose of the Study:

• To investigate the correlation between specific anatomical parameters and lateral patellar maltracking during simulated pivot landings after MPFL reconstruction.
• To identify key factors contributing to patellar instability in a dynamic setting.

Main Methods:

• Dynamic simulation models of 13 subjects undergoing MPFL reconstruction were created.
• Simulated pivot landings were performed with and without an MPFL graft.
• Measurements included patellar height (Caton-Deschamps index), trochlear groove depth (lateral trochlear inclination), and tibial tuberosity position (lateral TT-PCL distance).

Main Results:

• All models without an MPFL graft dislocated; two models with a graft also dislocated.
• With an MPFL graft, lateral patellar shift correlated with Caton-Deschamps index (r2 > 0.35) and lateral trochlear inclination (r2 ≥ 0.45).
• Lateral patellar tracking during pivot landings was associated with patella alta and shallow trochlear grooves.

Conclusions:

• Anatomical factors like patellar height and trochlear groove depth are critical predictors of patellar stability after MPFL reconstruction.
• Simulating high-risk activities like pivot landings is essential for evaluating patellar stability.
• Addressing these anatomical issues may reduce the risk of redislocation.