Lateral release associated with MPFL reconstruction in patients with acute patellar dislocation

Area of Science:

• Orthopedic surgery
• Biomechanics
• Sports medicine

Background:

• Medial patellofemoral ligament (MPFL) injuries are common in acute patellar dislocations.
• The role of concurrent lateral retinaculum release during MPFL reconstruction is not well-defined.
• Existing studies show mixed outcomes regarding lateral retinaculum release during MPFL reconstruction.

Purpose of the Study:

• To investigate the biomechanical effects of concomitant lateral retinaculum release during MPFL reconstruction.
• To hypothesize that lateral release disrupts patellofemoral joint biomechanics, causing lateral patellar instability.

Main Methods:

• Utilized a validated finite element (FE) model of the patellofemoral joint.
• Simulated the effects of lateral retinaculum release following MPFL reconstruction.
• Measured contact pressure (CP), contact area (CA), and lateral patellar displacement.

Main Results:

• Lateral retinaculum release decreased CP by 39-45% and CA by 44% compared to intact or MPFL reconstruction alone.
• Lateral patellar displacement increased by 20-21% after lateral retinaculum release.
• These effects were more pronounced with increased knee flexion.

Conclusions:

• Concomitant lateral retinaculum release with MPFL reconstruction decreases patellofemoral contact area and pressure.
• This surgical approach increases lateral patellar displacement, potentially elevating the risk of patellar instability.
• Further biomechanical understanding is needed for optimal surgical techniques in MPFL reconstruction.