The static stabilizing function of the popliteal tendon in the knee. An experimental study

Area of Science:

• Orthopedics
• Biomechanics
• Sports Medicine

Background:

• The anterior cruciate ligament (ACL) is a primary knee stabilizer.
• The role of lateral compartment ligaments and the popliteal tendon (PT) in knee stability is less understood.
• Understanding these structures' contributions is vital for diagnosing and treating knee injuries.

Purpose of the Study:

• To investigate the biomechanical importance of the ACL, its components, and lateral structures, including the PT.
• To determine their roles in resisting valgus-varus, axial rotation, and anterior-posterior knee instability.
• To elucidate the popliteal tendon's specific contribution to knee joint stability.

Main Methods:

• Utilized 15 cadaveric knee preparations.
• Performed successive transection of various knee ligaments and structures.
• Assessed mobility patterns and instability under different loading conditions (valgus-varus, axial rotation, anterior-posterior).

Main Results:

• Anterior tibial displacement required ACL transection, even with combined lateral structure lesions.
• Lateral structures acted as secondary restraints to anterior displacement and anterolateral rotation.
• Popliteal tendon (PT) transection significantly worsened varus instability, especially from 0-90 degrees flexion, even with an intact ACL.
• Posterolateral instability was significantly reduced with an intact PT.
• Maximum instability occurred at 30-40 degrees of flexion after combined lateral lesions.

Conclusions:

• The ACL is the primary restraint against anterior tibial displacement.
• The popliteal tendon (PT) is a critical secondary stabilizer, particularly for varus and posterolateral rotational stability.
• Combined injuries to lateral structures and the PT can lead to significant instability, especially in mid-flexion.