Novel assessment techniques to diagnose syndesmotic instability

If not treated or missed, syndesmotic instability may lead to osteoarthritic changes over time and impact patient quality of life and function. Syndesmotic instability should be treated surgically with either a static or dynamic treatment strategy. This thesis aims to improve existing diagnostic assessment techniques of the syndesmosis and to develop new ones in three parts, including I. arthroscopic assessment for diagnosing syndesmotic instability, II. new methods for diagnosing syndesmotic instability using portable ultrasound and weightbearing computed tomography (CT), III. methods to assess radiographic and patient functional outcomes after treatment.
The key takeaways from this thesis are:
1. The 2.0 mm threshold value of arthroscopic distal tibiofibular diastasis may lead to overtreatment of coronal syndesmotic instability.
2. Dynamic ultrasound allows one to evaluate sagittal translation of the distal tibiofibular joint effectively and reliably.
3. In biomechanical research portable ultrasound performed like arthroscopy when diagnosing syndesmotic instability in the sagittal plane.
4. In biomechanical research portable ultrasound could reliably detect tibiofibular clear space opening after external rotation stress.
5. (portable) Ultrasound is readily available, non-invasive, low-cost, affording contralateral comparison, and therefore a technique worth investigating further.
6. Weightbearing CT scan is a very promising technique for diagnosing syndesmotic instability.
7. Syndesmotic area seems the best and most reliable 2D parameter to detect instability or (mal)reduction of the syndesmosis.
8. Screw and tightrope reduction techniques do not restore syndesmotic area as compared to the intact contralateral ankle.
9. We found no difference in clinical outcomes between screw and tightrope reduction techniques.