![]() >60º or radiolunate or capitolunate angle >15º Ligamentous instability: increased scapholunate angle: i.e. Proximal pole: ~30-40% chance of non-union There are a number of factors that affect prognosis 23:ĭistal pole: the excellent likelihood of union (~100%) Union rates of surgical management approach Normal radiograph but a high index of suspicionįractures with 1 mm displacement but no significant deformity or angulation (e.g. Immobilization with thumb spica (or short arm) cast application 22,23 Management options can broadly be divided into non-operative or operative management. If these repeat films are negative also, then MRI (or bone scan if MRI is unavailable) should be recommended if clinical suspicion persists 1. Importantly if no fracture is seen it is essential to recommend repeat x-rays (including dedicated scaphoid views) in 7-10 days 1. Colles fracture or other carpal bone fracturesĮvidence of osteonecrosis if the fracture is subacute Lunate dislocation ( trans-scaphoid perilunate dislocation)Īssociated fractures: e.g. Humpback deformity due to angulation between proximal and distal parts Location (distal pole, waist, proximal pole) In addition to stating that a fracture is present, a number of features should be sought and commented upon: Bone scans will be most sensitive 3-4 days following the injury. An occult fracture will appear as a region of increased uptake, whereas osteonecrosis will demonstrate a photopenic region at the lower pole of the scaphoid. Nuclear medicineĪlthough bone scans are more sensitive than plain radiographs, they are usually reserved for patients with ongoing pain despite normal serial plain films 8, 13. It is also useful in assessing for osteonecrosis. MRI is the most sensitive modality for trabecular fractures, and this can detect completely undisplaced fractures, especially in the first 24 hours following injury 9,13. CT also is useful in assessing bone union 8. CT is useful for staging scaphoid fractures if surgery is considered and when fractures of the carpus are extensive or complex. CT may be insensitive to trabecular injury 5. Reported sensitivities, specificities and negative predictive values for CT have been reported CT to be 89-90%, 85-100%, and 97-98% respectively. CTĬT may be used for diagnosis when plain films are normal because it is readily available and quick 12. Fractures may be associated with overlying heterogenous collections which do not deform with compression by the transducer, representing hematomas 19. Ultrasonography may be used as an adjunctive imaging modality in the detection of acute scaphoid fractures. Sonographic windows commonly obtained include longitudinal and transverse views at the radial border of the wrist, volar wrist just medial to the thenar eminence, and dorsal wrist adjacent to lister's tubercle 18.įocal interruption of the thin echogenic cortex serves as direct sonographic evidence of fracture. With time the proximal part undergoes osteonecrosis, becomes increasingly sclerotic and can "implode" and fragment with secondary osteoarthritic changes 9. This can be on account of the rest of the wrist undergoing demineralization due to immobilization, whereas the proximal portion being bereft of blood supply retains its calcium. ![]() If osteonecrosis develops the first sign will be slight sclerosis. Scaphoid fat pad sign: obliteration or lateral displacement of a straight/convex lucent line on the lateral aspect of the scaphoid 11Īssociated scapholunate ligament disruption ( Terry Thomas sign) which can be accentuated with a clenched fist view Soft tissue swelling and lateral displacement of the adjacent fat pads Visualization of the fracture +/- displacement It should, however, be noted that the initial radiograph can miss from 5-20% of fractures in the acute setting 1. It is positionally different from the wrist series. Herbert and Fisher classification of scaphoid fracturesĪ dedicated plain radiographic series investigating the scaphoid exists, consisting of four projections of the scaphoid bone. Mayo classification of scaphoid fractures ![]() shot putters or gymnasts) 8.įractures can occur essentially anywhere along the scaphoid, but distribution is not even 16:ĭistal pole (or so-called scaphoid tubercle): 20% Occasionally stress fractures are also encountered although these are less common, and only usually seen in athletes (e.g. The usual mechanism is falling on an outstretched hand, applying an axial load to an extended and pronated wrist in ulnar deviation 7.
0 Comments
Leave a Reply. |