Keywords:
Education and training, Education, Diagnostic procedure, Complications, MR, Trauma, Musculoskeletal system, Musculoskeletal bone
Authors:
M. Kljaic Dujic, J. Vidmar, M. Rupreht; Maribor/SI
DOI:
10.26044/essr2019/P-0136
Imaging findings OR Procedure Details
A non-union scaphoid fracture is an unhealed fracture lasting more than 6 months after injury (non-union rate between 10–15%).
Untreated non-union SF can be stable (fibrotic) or unstable (cystic and sclerotic).
Previous studies have defined union when the bridging rate is at least 50%.
A recent study (Brekke,
2018) has shown that biomechanical strength and stability are already maintained with at least 25% of bridging.
It is of great importance to describe the exact location of the fracture line and dislocation.
There are many classification systems; however,
Mayo,
Russe and Herbert are most widely used.
Mid-portion (“waist”) fractures are most common,
while proximal portion has a higher risk of hypoperfusion due to specific vascular supply.
Contrast agent application and dynamic MRI may be helpful in viability assessment.
Unstable long-standing SF can lead to scaphoid non-union advanced collapse (SNAC) i.e.
different stages of secondary posttraumatic osteoarthrosis (I-IV) due to higher fragment mobility and abnormal carpal kinetics.
The advanced osteoarthritis stage (IV) may be eligible for a 4-corner fusion.
Surgical treatment depends on risk factors (location,
fragment dislocation,
vascularity and viability) and the best surgical procedure remains controversial.
Delayed union or non-union are most often treated by open reduction and internal fixation.
Recently,
a bone grafting procedure has been developed to improve the bony union.
Also,
new materials are becoming more and more important.
Santos and authors (2018) have presented pyrocarbon implant hemiarthroplasty,
as save technique in treatment of the scaphoid proximal pole after AVN.
3DCT multiplanar reconstruction with 3 dimensional (3D) printing of scaphoid model are becoming more useful.
Scaphoid bone,
because of its complex anatomy,
size and shape,
is technically challenging for surgeons.
3D models of complex anatomical structures can save time in operation room.
Computer-assisted system (CAS) are in experimental phase.
Xiao and authors (2018) have published better reliability,
accuracy and outcome with CAS especially with small bones like scaphoid,
because deviations during surgery are more obvious with small bones than in bigger.
Improvements in machine learning algorithms resulted in better automatic annotation tool as a new detection support system.
Foufi and authors (2018) found out that detection between automatic and manual technique was high and very similar (96,8 % of total match).