Acute posterolateral rotatory instability of the knee

Area of Science:

• Orthopedic Surgery
• Sports Medicine
• Knee Biomechanics

Background:

• Posterolateral rotatory instability (PLRI) is a complex knee injury.
• Diagnosis can be challenging, often involving multiple ligamentous injuries.

Purpose of the Study:

• To identify diagnostic features of acute PLRI.
• To evaluate the effectiveness of surgical repair for PLRI.

Main Methods:

• Retrospective review of 17 patients with acute PLRI.
• Clinical assessment including specific physical tests (external-rotation recurvatum, adduction-stress, posterolateral-drawer).
• Follow-up evaluation of 13 surgically treated patients after a mean of 53.3 months.

Main Results:

• Positive external-rotation recurvatum and posterolateral-drawer tests were diagnostic of PLRI.
• Adduction-stress test at 30° flexion was often positive but not diagnostic.
• All patients had arcuate ligament complex injuries; 10 had associated rotatory instabilities.
• No patients required further reconstruction; 85% reported good subjective outcomes and 77% good objective outcomes.
• 85% returned to pre-injury athletic levels.

Conclusions:

• Specific physical examination tests are crucial for diagnosing acute PLRI.
• Surgical repair in the acute phase yields favorable subjective and objective results.
• Prompt diagnosis and treatment of PLRI improve knee function and enable return to sport.