Diagnosis of knee instability using sonography.

Area of Science:

• Orthopedics
• Diagnostic Imaging
• Biomechanics

Background:

• Conventional instrumental testing for knee instabilities lacks reproducibility and reliability.
• Accurate, quantifiable assessment of knee joint stability is crucial for effective treatment.

Purpose of the Study:

• To develop and validate a sonographic method for diagnosing knee joint instabilities.
• To achieve exact, quantifiable, and reproducible measurements of knee instability.

Main Methods:

• A novel positioning device was developed for sonographic analysis of knee instabilities based on biomechanical principles.
• Sonography visualized the cortical lines of the femur and tibia while controlled translation was induced.
• Standard values for physiological knee joint translation were established in 142 healthy individuals across different age groups.

Main Results:

• The developed sonographic technique and device provide reliable and exact measurements for knee instability in various translation directions.
• Healthy subjects exhibited greater lateral compartment translation than medial.
• Translation increased with age in individuals over 30 years.
• A significant difference (p=0.0001) was found between knee stability and instability, allowing differentiation of partial/total ACL ruptures and chronic instabilities.

Conclusions:

• The sonographic method accurately diagnoses and quantifies knee instabilities, outperforming traditional instrumental techniques.
• It enables precise differentiation between various types of knee instabilities, including partial and total ACL ruptures.
• This diagnostic capability facilitates exact monitoring of both conservative and operative treatment outcomes.