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Rotational motion of the knee.
The American Journal of Sports Medicine
|May 1, 1983
Summary
Quantifying knee axial rotation reveals significant differences in patients with anterolateral rotatory instability. Increased rotational motion, especially at low flexion angles, indicates potential ligamentous injury.
Area of Science:
- Orthopedics
- Biomechanics
- Sports Medicine
Background:
- Anterolateral rotatory instability (ALRI) is a common knee injury.
- Accurate quantitation of knee axial rotation is crucial for diagnosis and treatment.
Purpose of the Study:
- To quantify passive axial rotation of the knee across various flexion angles.
- To compare rotational knee motion between healthy subjects and patients with ALRI.
Main Methods:
- Passive knee rotation was measured at multiple flexion angles (5 to 90 degrees).
- Measurements were taken on 17 healthy subjects and 19 patients with unilateral ALRI.
Main Results:
- Normal knees exhibited symmetric rotational motion, with greater rotation at 30-90 degrees flexion (45° external, 25° internal) than at 5 degrees flexion (23° external, 10° internal).
- Patients with ALRI showed similar rotation to controls between 30-90 degrees flexion.
- At 5 degrees flexion, ALRI knees demonstrated significantly increased external (41°) and internal (14°) rotation compared to normal knees.
Conclusions:
- Knee axial rotation quantitation can help identify ALRI.
- Increased external and internal rotation at low flexion angles (around 5 degrees) is a key indicator of ALRI, likely due to anterior cruciate ligament compromise.