Occult Fractures

With non-displaced occult fractures, the fracture line will appear as an area of low signal intensity within the oedematous marrow. Stress fracture lines are typically linear. The use of gradient echo or T1 weighted sequences to identify loss of the normal hony trabecular pattern can also be used. MRl will also allow detection of fractures through unossified portions of the skeleton. (Figs. 5.9a,b, 5.10,5.11). 

Either skeletal survey or bone scintigraphy alone will miss occult fractures... 

For paediatric ankle injuries with normal radiographs, high resolution ultrasound has been shown to be useful in diagnosing occult fractures (SiMANOVSKY et al. 2005) and ligamentous injuries (Farley et al. 2001). The majority of these occult fractures are Salter-Harris I or II fractures of the distal fibular physis. If left undiagnosed and untreated the majority of such injuries would have a satisfactory outcome. 

Simanovsky N, Hiller N, Leibner E et al (2005) Sonographic detection of radiologically occult fractures in paediatric ankle injuries. Pediatr Radiol 35 1062-1065 Spiegel PC, Cooperman DR, Laros GS (1978) Epiphyseal fractures of the distal ends of the tibia and fibula. A retrospective study of 237 cases in children. J Bone Joint Surg 60A 1046-1050... 

Three fat pads lie over the capsule, the anterior over the coronoid fossa, the posterior over the olecranon fossa and a third over the supinator as it wraps over the radius. Fracture, haematoma and effusion into an intact capsule may cause capsular distension, which can distort these fat pads, improving their visibility and identifying occult fractures (Fig. 18.4). In the setting of acute trauma, a visible... 

Skaggs DL Mirzayan R (1999) The posterior fat pad sign in association with occult fracture of the elbow in children. 

Radiological studies may be necessary to rule out occult fractures or dislocations despite the fact that the majority of films show only an alteration in the cervical lordosis, either a flattening or an actual reversal of the curve. A significant reversal ofthe curve undoubtedly indicates some degree of structural damage. 

Bone scan A bone scan is particularly useful in a search for cancerous metastatic disease and should be used when there is a suspicion of this. Occult fractures may also be detected. 

Wakefield RJ, Gibbon WW, Conaghan PG et al (2000) The value of sonography in the detection of bone erosions in patients with rheumatoid arthritis a comparison with conventional radiography. Arthritis Rheum 43 2762-2770 Wang CL, Shieh JY, Wang TG et al (1999) Sonographic detection of occult fractures in the foot and ankle. J Clin Ultrasound 27 421-425... 

Fig. 8.74a-d. Occult fracture of the right coronoid process in a woman following a ski accident, a The patient had a negative radiographic examination performed soon after the injury, b Two weeks later, she was submitted to US examination due to persistent elbow pain and loss of extension. US identified an interruption (curved arrow) of the hyperechoic cortical profile of the coronoid process (C), just cranial to the insertion of the brachialis (br). There was associated mild intra-articular effusion. HC, humeral capitellum. c Left healthy side for comparison, d Additional oblique view of the right elbow confirms the fracture... 

Lazar RD, Waters PM, Jaramillo D (1998) The use of ultrasonography in the diagnosis of occult fracture of the radial neck. J Bone Joint Surg Am 80 1361-1364 Levin D,Nazarian LN, Miller TT et al (2005) Lateral epicondylitis of the elbow US findings. Radiology 237 230-234 Liessi G, Cesari S, Spaliviero B et al (1996) The US, CT and MR findings of cubital bursitis a report of five cases. Skeletal Radiol 25 471-475... 

Major NM, Crawford ST (2002) Elbow effusions in trauma in adults and children is there an occult fracture AJR Am J Roentgenol 178 413-418... 

The scaphoid is the most common site of occult fractures in the wrist area, with up to 20-25% of cases unnoticed at the initial evaluation (Waizenegger et al. 1994). When the diagnosis is delayed, scaphoid fi actures have high rates of complications such as pseudoarthrosis, avascular necrosis of the proximal pole of the bone and secondary radiocarpal osteoarthritis with chronic pain and impaired function. A variety of diagnostic modalities, such as additional radiographic views, bone scan, CT and MR imaging, have been advocated for early detection of scaphoid fractures. The choice between an addi-... 

Due to the anatomic complexity of the hip, some undisplaced fractures or bone avulsion injuries at the tendon attachments on the bone may go unnoticed on plain films, even when additional projections are performed. In these cases, the patient may be submitted to US examination of the hip due to persistent pain and disability in order to rule out soft-tissue abnormalities. With careful scanning technique, US is able to identify occult fractures around the hip based on detection of either a step-off deformity or focal discontinuity or fragmentation of the hyperechoic cortical line (Fig. 12.69). In these instances, additional radiographic or CT studies should always be obtained to confirm the US diagnosis. 

Wang CL, Shieh JY. Wang TG et al (1999) Sonographic detection of occult fractures in the foot and ankle. J Clin Ultrasound 27 421-425... 

Lee MC, Eberson CP (2006) Growth and development of the child s hip. Orthop Clin North Am 37 119-132 Leibowitz E, Levin S,Torten J et al (1985) Interferon system in acute transient synovitis. Arch Dis Child 60 959-962 Lin JN, Chou ML (1997) Ultrasonographic study of the sternocleidomastoid muscle in the management of congenital torticollis. J Pediatr Surg 32 1648-1651 Loder RT (1996) A worldwide study on the seasonal variation of slipped capital femoral epiphysis. Clin Orthop 322 28-36 Major NM, Crawford ST (2002) Elbow effusions in trauma in adults and children is there an occult fracture AJR Am J Roentgenol 178 413-418... 

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