What did the study look at?
Magnetic resonance imaging (MRI) is generally preferred for assessing knee cartilage and the bone beneath it. Real-time elastosonography (RTE) is an ultrasound technique that shows how stiff or soft a tissue is. As the authors explain, healthy cartilage is a stiff tissue that loses its stiffness in damaged areas.
The aim was to assess, in a cadaver model, how effective a new diagnostic method combining ultrasound and elastosonography would be when applied from inside the joint together with arthroscopy.
How was it done?
- 12 fresh human cadaver knees of unknown age and sex were used, mounted on a device with the knee bent at 90 degrees.
- The joint was examined through standard arthroscopy portals (anteromedial and anterolateral), and a 10 mm laparoscopic ultrasound probe with elastography capability was then placed inside the joint.
- Chondral and osteochondral defects were created with mosaicplasty instruments in healthy-looking areas of the femoral cartilage.
- Tissue strain was measured in intact and damaged areas within the same image window. On the colour map, blue indicated the stiffest and red the softest tissue.
- Assessments were made jointly by an orthopaedic surgeon and a musculoskeletal radiologist.
What did it find?
- Median cartilage thickness was 1.90 mm on the lateral condyle and 1.95 mm on the medial condyle. The created defects measured 9.85 mm on average.
- Median strain in the damaged cartilage was significantly higher than in intact cartilage: 1.23 versus 0.01 (p=0.002). Higher strain indicates softer tissue.
- In very superficial defects a measurement area could not be placed, so no numerical value was obtained, although the colour change was clearly visible.
- Most of the joint surface could be viewed; the posterior and superior parts of the femoral condyle could not.
The authors' conclusion
The authors conclude that arthroscopic examination of cartilage with elastosonography may guide orthopaedic surgeons, and that arthroscopic assessment of knee cartilage and subchondral bone could benefit from this method. They hope the work will support further studies and the production of probes suited to use inside the joint.
Limitations
- The study was carried out only on cadavers, and the defects assessed were created for the study.
- Arthroscopy and ultrasound were performed by different physicians.
- The sample was small; the authors state this was set by the project budget.
Reference
Akkaya M, Cay N, Gürsoy S, Simsek ME, Tahta M, Doğan M, Bozkurt M. Sonoelastography of the knee joint. Clinical Anatomy. 2019;32(1):99–104. © 2018 Wiley Periodicals, Inc.
DOI: 10.1002/ca.23300
Free full text: Ankara Yıldırım Beyazıt University open repository (PDF)
This article summarises a published scientific paper for general information; it does not replace an examination or a personal medical assessment. Please consult your doctor about your symptoms.
