The wrist is the most commonly injured site in the skeleton, accounting for between 3% and 9% of athletic injuries. A fall onto an outstretched hand (FOOSH) is the typical mechanism.
Of potential bone fractures, those affecting the distal radius and ulna are the most prevalent. When carpal bones are affected, the scaphoid comprises 60% to 70% of fractures.
Carpal dislocations occur less frequently than fractures, though make up about 10% of carpal injuries. The three main dislocations are perilunate, lunate, and scaphoid – scapholunate dissociation. This latter carpal dislocation is often associated with fracture of the distal radius. Ligaments injured to varying degrees include:
- Perilunate dislocation – radioscaphocapitate, scapholunate interosseous and lunotriquetral interosseous ligaments
- Lunate dislocation – all perilunate ligaments, most significantly the dorsal radiolunate ligament
- Scapholunate dissociation – scapholunate and radiolunate ligaments.
Given the complexity of the wrist, a combination of imaging modalities is typically necessary to compliment patient history and clinical examination of FOOSH injuries. X-ray is valuable for initial investigation of any fractures/dislocations and 5-10 day follow-up imaging, particularly if occult scaphoid fracture is suspected. CT and/or tomosynthesis, a new type of X-Ray/CT hybrid imaging modality, may be required to better appreciate complex or occult fractures. MRI plays an important role in the assessment of ligament integrity and other soft tissue involvement.
Case Example
Mr M, a 41 year old office worker was referred by his health care practitioner for a right wrist MRI study due to persisting pain following a motorbike accident. Initial x-rays demonstrated a widened scapholunate articulation. Symptoms were intermittent and particularly aggravated by hand shaking when greeting people. Tenderness was elicited over the proximal row of carpal bones towards the thumb.
Key MRI findings were:
- Complete scapholunate ligament tear with mild scapholunate dissociation.
- Mid-carpal and intercarpal effusions.
- Small, most likely degenerative, cysts located in the capitate and trapezoid, but no visible fracture.
To view this study in our online image viewer, click here. (Images may take awhile to download, depending on your internet download speed.)
Note: Image appearance is strongly influenced by computer monitor resolution; regular office computer monitors have lower resolution than the high-end monitors used by radiologists and in radiology centres.
If we can be of assistance with wrist imaging, contact us on 03 9592 3319.
As part of Brighton Radiology, an independent QIP Accredited Diagnostic Imaging Service, low dose CT, long view X-ray, multislice orthopaedic tomosynthesis (hybrid X-ray/CT) and general X-ray are also available.
References
Hayter C, et al. Magnetic resonance imaging of the wrist: Bone and cartilage injury. JMRI 2013;37:1005-1019.
Radiopaedia.org
Ringler M. MRI of Wrist Ligaments. J Hand Surg 2013;38A:2034–2046.
This is general health information designed for educational purposes only. It does not constitute individual health advice and should not replace thorough consultation with a registered health care practitioner.
