The Clinical Scaphoid Fracture: Early Computed Tomography as a Practical Approach

Abstract

Ann R Coll Surg Engl 2008; 90: 488-491 488Carpal injuries are common presentations to emergency departments, general practitioners and orthopaedic clinics. The scaphoid bone is the most commonly injured of the carpal bones accounting for 50-80% of carpal injuries and predominantly occurs in young. healthy individuals. 1,2Scaphoid fractures are the most problematic to diagnose in a clinical setting because it can take up to 6 weeks for scaphoid fractures to become conclusive on plain X-ray films. It is estimated that up to 40% of scaphoid fractures are missed at first presentation. 3,4 A recent metaanalysis of scaphoid fractures calculated that the positive predictive value of clinical examination (those who proved to be 'clinical scaphoid' warranted X-rays of scaphoid views who subsequently had scaphoid fracture) is in the range 13-69% with an average of 21%. 5This means that four out of five patients without a fracture will be unnecessarily immobilised before radiological diagnosis is confirmed. Patients and MethodsWe conducted a retrospective, chronological review of patients who attended an upper limb fracture clinic from January 2001 to October 2003 in a district general hospital. Patients with negative X-ray findings but positive clinical signs for scaphoid injury satisfied the criteria for CT. We defined clinical signs for a scaphoid injury as tenderness over the anatomical snuffbox, pain on axial loading of first metacarpal and tenderness over scaphoid tubercle in the presence of normal plain films and included patients whose plain X-rays proved inconclusive.Patients with clinical indications of scaphoid fracture but negative plain films had their wrists immobilised in a scaphoid cast in the accident unit while awaiting a hand clinic appointment.CT scans, where necessary, were carried out on the same day as review on the first presentation to the fracture

Predictors of fracture following suspected injury to the scaphoid

“…Using both conventional analysis and LCA, no single sign was found to be adequately sensitive and specific. [4][5][6][7][27][28][29]38 The latent class results are quite different from the reference standard based calculations, as was the case in a previous study that used latent class analysis to determine the performance characteristics of various diagnostic tests for the suspected scaphoid fracture. 20 As has been previously reported, 4,6,7,20,27,28 the sensitivity of all physical tests is consistently greater than the specificity, with the specificity of all tests increasing over time (with an associated drop in sensitivity).…”

‘Clinical scaphoid fracture’: is it time to abolish this phrase?

“…Bone scans have a higher sensitivity than radiographs and hence a number of patients may be over-treated. 3,15 Secondly, although it does allow for direct visualisation of the abnormal area, it may not be specific for a fracture or soft tissue injury. MRI has a better predictive value and is cost-effective.…”

Assessment of the suspected fracture of the scaphoid

“…No single sign has been found to be adequately sensitive or specific (Table I). 10,[41][42][43][44][45][46][47] Initial studies in this area examined the sensitivity and specificity of individual clinical signs. Freeland 41 reviewed 246 patients with a suspected fracture of the scaphoid and found that tenderness in the anatomical snuffbox had a sensitivity of 90% and a specificity of 40%, with tenderness of the scaphoid tubercle having a sensitivity of 87% and specificity of 57% for a scaphoid fracture.…”

“…7,8 However, more consistently, between 30% and 40% of fractures are not identified on initial assessment and investigation with four-view radiographs. [1][2][3]7,8,10,47,52,53 Radiographs have low inter-and intra-observer reliability for the diagnosis of suspected fractures of the scaphoid. 54,55 Low sensitivity on repeat radiological assessment has also been found, with one study 52 finding that it only identified 50% of occult scaphoid fractures.…”