Humeral shaft fracture

The radial nerve lies in the spiral groove on the back of the humerus and pierces the lateral intermuscular septum about 10 cm above the elbow. A spiral fracture of the distal third (Holstein–Lewis) can trap or tear it.

Mechanism

Fall or twisting injury (spiral, e.g. arm wrestling, throwing); direct blow (transverse).

Clinical findings

• Before and after any manipulation test the radial nerve: wrist and finger extension, sensation of the first dorsal web space (wrist drop in about 10%, mostly neurapraxia).

Imaging

• AP and lateral of the whole humerus, including shoulder and elbow.
• Document radial nerve function before and after any manipulation.

• Full-length AP and lateral including shoulder and elbow.

Classification

12A

Simple: A1 spiral, A2 oblique, A3 transverse.

12B

Wedge.

12C

Multifragmentary.

Types shown in 3D

12A1

Simple spiral (here distal third: Holstein–Lewis, radial nerve at risk).

12A2

Simple oblique.

12A3

Simple transverse: highest non-union rate with a brace.

12B2

Wedge (butterfly) fragment.

12C2

Segmental.

Treatment

Non-operative (most)

Coaptation (U) splint, then a functional (Sarmiento) brace for 8–12 weeks. Acceptable: < 20° anterior angulation, < 30° varus, < 3 cm shortening. Union in about 90%.

Operative

Open fractures, vascular injury, floating elbow, polytrauma, pathological fractures, failure of bracing or non-union: plate (anterolateral or posterior approach, protect the radial nerve) or intramedullary nail. Radial nerve palsy alone is not an indication; palsy appearing after manipulation is debated.

Aftercare

Pendulum exercises; avoid shoulder abduction in early bracing (varus).

Complications

• Radial nerve palsy (recovers in > 70%)
• Non-union (transverse, proximal third, obesity)
• Malunion (usually well tolerated)