Importance of bruising associated with paediatric fractures: prospective observational study

Few data are published on the bruising seen in association with paediatric fractures. What little can be found is set in the context of non-accidental injury. Differing opinions about the importance of bruising have been expressed by those working on medicolegal cases.^1–3 The force necessary to fracture a normal bone is thought to result invariably in external evidence of trauma.¹ The absence of such bruising has been taken to imply that minimal force was required to produce the fracture—that is, the fracture occurred because of metabolic bone disease or osteogenesis imperfecta.²,³

Subjects, methods, and results

We prospectively assessed 93 acute fractures in 88 normal children (49 boys and 39 girls; age range 12 months to 13 years 11 months) at presentation and before definitive treatment, looking for evidence of bruising around the fracture site. The prevalence of bruising at initial presentation and its incidence during early follow up was evaluated in subsets of fractures grouped according to displacement and extent of soft tissue cover. All the children were seen within 24 hours of injury.

There were 17 undisplaced, 46 displaced, and 30 angulated (>15°) fractures. Simple falls accounted for 70 fractures (15 undisplaced, 25 angulated, 30 displaced); 23 fractures were the result of falls from heights (2 undisplaced, 5 angulated, 16 displaced). Bruising was seen at initial presentation in 8 fractures (9%), which were either displaced or superficially located, or both. Bruising was not present at initial presentation in undisplaced fractures or those well covered by soft tissues.

Seventy three fractures were examined at the time of primary treatment under anaesthesia in the first 24 hours after admission to hospital. This group included the 8 fractures with bruising evident at initial presentation. Thirteen other fractures in this group (without evidence of bruising at initial presentation) had developed overt bruising by the time of definitive treatment within 24 hours of hospital admission. Sixteen fractures were reviewed later in the first week for various reasons (for example, change of plaster casts, remanipulations); 4 of these had developed local bruising. Four fractures were reviewed at three weeks when a plaster cast was removed. They were all undisplaced distal radial fractures that had not required manipulative treatment, and bruising was not evident in any of them. Thus 25 fractures (28%) developed bruising during the first week after trauma.

Comment

The absence of bruising in children with fractures has been cited as supporting evidence that the force required to fracture the bone was minimal, which implies weakness of the underlying bone—perhaps due to a temporary abnormality such as copper deficiency or subtle forms of osteogenesis imperfecta.¹,³ In our study of normal children most fractures (91%) were not associated with bruising at the time of presentation. Most (72%) remained without evident bruising in the first week after injury. We therefore suggest that the absence of bruising cannot be taken to imply either underlying bone disease or an increased possibility of non-accidental injury.

Local bruising in acute fractures in childhood is perhaps less common than might be expected. When present it implies that any underlying fracture is likely to be displaced. Its absence is an unreliable sign on which to base a diagnosis of non-accidental injury.

Editorial by Eastwood