Lateral patellar retinaculum tension in patellar instability.

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Sports Medicine

Background:

• The patellar retinaculum plays a crucial role in patellar tracking.
• The biomechanics of the patellar retinaculum, particularly the lateral patellofemoral ligament, are not well understood.
• Patellar instability necessitates surgical intervention, often involving tibial tubercle transfer.

Purpose of the Study:

• To evaluate changes in lateral patellofemoral ligament tension following anteromedial tibial tubercle transfer.
• To understand the biomechanical implications of this surgical procedure on patellar stability.
• To identify patterns of tension change that correlate with patellar instability.

Main Methods:

• Measurement of lateral patellofemoral ligament tension using a buckle transducer in 27 knees before and after anteromedial tibial tubercle transfer.
• Tension was recorded at knee flexion angles of 0, 30, 60, 90, and 120 degrees.
• Analysis of tension changes to identify distinct patterns related to patellar instability.

Main Results:

• Lateral patellofemoral ligament tension generally increased with knee flexion, peaking at 120 degrees.
• Four distinct patterns of tension changes were observed, reflecting variations in patellar instability.
• Post-anteromedial tibial tubercle transfer, increased lateral patellofemoral ligament tension was noted.

Conclusions:

• Increased lateral patellofemoral ligament tension after anteromedial tibial tubercle transfer suggests a potential need for concurrent lateral retinacular release.
• Balancing patellar tracking may require this combined surgical approach.
• Findings can inform surgical decision-making for individual patients with patellar instability.