Beware of ulnar nerve entrapment in flexion-type supracondylar humerus fractures

Abstract

Purpose A recent study reported a higher incidence of pre-operative ulnar nerve symptoms in patients with flexion-type supracondylar fractures than in those with the more common extension supracondylar fractures and a greater need for open reduction (Kocher in POSNA paper #49 2006). We have encountered a specific pattern of flexion supracondylar fractures that often require open reduction with internal fixation (ORIF) due to entrapment of the ulnar nerve within the fracture. Methods Medical records and X-rays from 1997 to 2005 at our children's hospital were examined to identify flexion supracondylar fractures that required open reduction. The operative reports were reviewed to identify cases that had the ulnar nerve blocking the reduction. Results During the 8 years examined, 1,650 supracondylar fractures had been treated by means of closed reduction and percutaneous pinning. Of these, only 1.8% or 30 cases could not be reduced closed and required open reduction internal fixation, excluding 11 open fractures. Of the 30 fractures requiring open reduction internal fixation, 24 were of the extension type needing ORIF because of interposed periosteum/muscle. The other 6 patients had flexion-type supracondylar fractures that failed closed reduction. All had a persistent medial gap at the fracture site. All 6 fractures had interposed periosteum or muscle, while in 3 cases the ulnar nerve was also entrapped within the fracture site (Figs. 1, 2) Conclusion Flexion-type supracondylar fractures remain a relatively uncommon variant (2-3%) of supracondylar fractures. Recent reports have noted that open treatment of these fractures is required more frequently than for extension fractures. In our series, 20% of the open cases were flexion-type fractures and in half of these the ulnar nerve was found to be entrapped in the fracture, preventing reduction.

Flexion type supracondylar humerus fractures: 12 year experience of a pediatric orthopedics clinic

“…In the present study, 13.6% (n=3) of type 3 fractures had ulnar nerve symptoms preoperatively. Although we had performed lateral exposure for open reduction, medial exposure can be more reliable and safer to explore the ulnar nerve for the fractures that have ulnar nerve symptoms preoperatively in which open reduction is needed as stated by Steinman et al [16] In De Boeck's [3] series, 86% of patients had excellent and good results and 14% had fair results according to Flynn criteria. Our results were similar with De Boeck's series.…”

Flexion-Type Supracondylar Humeral Fracture with Ulnar Nerve Injury in Children: Two Case Reports and Review of the Literature

“…The most common cause of flexion-type SHF in children is a direct fall on the elbow, which results in failure of the posterior cortex and thus anterior angulation of the distal fragment [4]. Flexion-type fractures are classified as extension-type fractures according to Gartland classification system as nondisplaced, partially displaced, and completely displaced [8,9].…”

“…Although extension-type fractures are associated more with brachial artery and anterior interosseous nerve injury, the flexion-type fractures, in contrast, are associated with ulnar nerve injury [3,13]. The ulnar nerve can be injured either 1) because it can become entrapped between the distal and the proximal fragment or 2) because the nerve can become stretched over the posterior spike of the proximal fragment or 3) from the placement of a K-wire on the medial side, near the cubital tunnel [4,14]. Most injuries are neurapraxia rather that axonotmesis or neurotmesis and usually resolve in less than 6 months, approximately 10 weeks.…”

“…Flexion-type SHF occurs mainly by directly falling on the elbow rather than falling on an outstretched hand [4]. Treatment of flexion-type fractures can be either closed reduction and casting, closed reduction and percutaneous pinning, or open reduction and pinning depending on the degree of displacement [4,5]. Nevertheless, they are considered more severe injuries with more complications than extension-type SHFs [6].…”

Management of supracondylar fractures of the humerus in children

“…Flexion-type fractures involve neurovascular structures more frequently than extension-type fractures, especially ulnar nerve entrapment at the fracture site. 95…”