Must a Knee with Anterior Cruciate Ligament Deficiency and High-grade Pivot Shift Test Present an Increase in...

Area of Science:

• Orthopedic Surgery
• Sports Medicine
• Biomechanics

Background:

• Anterior cruciate ligament (ACL) ruptures are common in athletes.
• ACL injuries often involve anterolateral structures, leading to a high-grade pivot shift test.
• The relationship between ACL deficiency, pivot shift severity, and internal knee rotation requires further investigation.

Purpose of the Study:

• To test the hypothesis that ACL deficiency with a high-grade pivot shift test correlates with increased internal knee rotation.
• To quantify the degree of internal rotation in ACL-deficient knees based on pivot shift test grading.

Main Methods:

• Twenty-two patients underwent testing under spinal anesthesia.
• The manual pivot shift test was performed to grade the severity of the instability.
• Internal knee rotation was measured with the knee flexed at 90 degrees by assessing foot projection.

Main Results:

• A statistically significant average internal rotation increase of approximately 10.5 degrees was observed in ACL-deficient knees compared to controls.
• This significant increase in internal rotation was consistent regardless of age adjustment.
• No significant increase in internal rotation was found in ACL-deficient knees with a grade I pivot shift test.

Conclusions:

• ACL deficiency combined with pivot shift test grades II and III is associated with significantly increased internal knee rotation.
• ACL deficiency with a grade I pivot shift test does not demonstrate a significant increase in internal rotation compared to intact ACL knees.
• These findings highlight the clinical significance of the pivot shift test in assessing rotational knee instability in ACL-deficient athletes.