Radial nerve entrapment after fracture of the supracondylar humerus: a rare case of a 6-year-old

Abstract

Supracondylar fracture of the humerus is one of the most common fractures seen in children, and posteromedial displacement of the distal fragment in extension-type supracondylar humerus fractures can cause injury to the radial nerve. A 6-year old girl who presented with symptoms of radial nerve injury after a supracondylar fracture of the right humerus with complete posteromedial displacement of the distal fragment (Gartland type III) underwent surgery where closed reduction and percutaneous pinning was performed. The patient was routinely followed up and at 6 months postoperatively no neurological improvement was seen. Exploratory surgery revealed complete discontinuation of the radial nerve at the fracture site and entrapment of the nerve stumps in healed bone callus. A gap of 2 cm was observed between nerve stumps, and sural nerve cable grafting was performed with good results. If neurological symptoms do not improve over time, appropriate differential diagnosis and, if necessary, exploratory surgery should be considered. Despite limited reports and their conflicting outcomes, sural nerve cable grafting could be a useful option to bridge the gap of discontinued nerve injury. Level of Evidence: Level IV, Case Report.

Figure 1. A-C.

(A) Initial radiograph of the right elbow showing supracondylar humerus fracture with complete posteromedial displacement of the distal fragment (Gartland type III). (B) Immediate postoperative radiograph of the right elbow shows that the supracondylar humerus fracture is reduced and fixed using 3 Kirschner wires (2 lateral pins and 1 medial pin). (C) Postoperative 3 months radiograph of the right elbow showing a completely unioned fracture.

Figure 2.

Postoperative 5 months clinical photo when the patient was asked to extend wrist joint showing that radial nerve symptoms persisted.

Figure 3.

Postoperative 5 months magnetic resonance image of the right elbow showing invisible radial nerve at the supracondylar level of the humerus and mild atrophy of the supinator muscle.

Figure 4. A-C.

(A) Intraoperative photograph during exploration surgery showing that the radial nerve was completely discontinued in the previous fracture site with proximal and distal nerve stumps entrapped in healed bone callus. (B) After detachment and resection of nerve stump, there was a 2 cm gap between proximal and distal stumps. (C) After 11 cm of sural nerve of the contralateral calf was harvested using separate incisions, nerve coaptation was performed under a microscope using 9-0 monofilament sutures.

Figure 5.

Postoperative 1-year clinical photo when the patient was asked to extend wrist joint showing improved radial nerve symptoms. She obtained a full active range of motion of the wrist joint and thumb with a near-full active range of motion of metacarpophalangeal joints.

Figure 6.

Postoperative 4-year clinical photo when the patient was asked to extend wrist joint showing improved radial nerve symptoms. The extension lag of the second metacarpophalangeal joint also showed improvement.