Humeral Shaft Fracture Fixation (Plating vs Nailing)

The central decision. The default for an isolated, closed humeral shaft fracture with acceptable alignment is non-operative treatment in a functional (Sarmiento) brace. The humerus is a non-weight-bearing bone surrounded by generous soft tissue, and the shoulder and elbow compensate for residual deformity, so union rates with bracing are high (commonly quoted around 90 percent in classic series) with good functional outcomes. The FISH randomised trial confirmed that bracing and plating give similar 12-month function in closed fractures, though bracing carries a higher secondary-surgery rate for nonunion. Acceptable alignment (the limits in a brace). Deformity within these limits is cosmetically and functionally acceptable, and it is failure to maintain these limits — not minor in-range angulation — that triggers operative conversion.

• Up to about 20 degrees anterior angulation
• Up to about 30 degrees varus or valgus angulation
• Up to about 3 cm shortening
• Rotational malalignment is also generally well tolerated Functional bracing protocol (Sarmiento).
• Initial management in a coaptation (U-slab) splint or hanging cast for 1 to 2 weeks to settle pain and swelling
• Transition to a prefabricated functional brace once acute swelling subsides
• The brace works by soft-tissue compression (the hydraulic effect) maintaining alignment while gravity provides traction; early shoulder pendulum and elbow motion are encouraged
• Weekly radiographs initially to confirm alignment stays within acceptable limits
• Brace continued until clinical and radiographic union (typically 8 to 12 weeks) Operative indications — patient and injury factors that mandate or favour surgery.
• Open fracture (debridement plus stabilisation)
• Vascular injury requiring repair — stabilise the bone to protect the vascular reconstruction
• Polytrauma — fixation permits early mobilisation, frees the limb for weight-bearing through aids, and aids nursing
• Floating elbow (ipsilateral humeral and forearm fracture)
• Bilateral humeral shaft fractures (bracing both is impractical)
• Pathological or impending pathological fracture
• Segmental fracture
• Failure to maintain acceptable reduction in a brace (loss of position beyond the limits above)
• Inability to tolerate or comply with bracing (for example large body habitus, significant soft-tissue interposition, cognitive or social factors)
• Selected radial nerve palsies — open injury, after penetrating trauma, or a palsy that develops after closed reduction or manipulation (explore) Radial nerve palsy — the decision logic.
• Primary palsy in a closed fracture: observe. About 90 percent are neuropraxia or axonotmesis that recover spontaneously by 3 to 4 months. Document a baseline examination, splint the wrist and fingers to prevent contracture, and obtain EMG/NCS at around 6 weeks and 3 months to track recovery.
• Secondary palsy (after reduction or manipulation): explore — the nerve may be entrapped in the fracture or have been injured by the manoeuvre.
• Open fracture or penetrating trauma with palsy: explore the nerve at the time of debridement and fixation.

The goal is to expose the relevant level of the shaft, identify and protect the radial nerve, reduce the fracture, and apply stable fixation — plating for the reference-standard open technique that also allows nerve exploration, or nailing where its biology and load-sharing are advantageous. The exposure defines the operation: the radial nerve runs in the spiral groove, crosses to lateral at the middle-to-distal third, and pierces the lateral intermuscular septum 10 cm above the lateral epicondyle, so the approach is chosen by fracture level and the nerve is protected in every posterior and distal-third exposure.

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Rehabilitation | Phase | Timing | Immobilisation / activity | Therapy focus | |-------|--------|---------------------------|---------------| | 1 | Day 0 to 14 | Sling for comfort after fixation; functional brace for non-operative cases | Early controlled shoulder and elbow motion as stability permits; wound check | | 2 | 2 to 6 weeks | Removable sling / brace; protect the shoulder after antegrade nailing while the cuff heals | Active-assisted shoulder and elbow ROM; maintain reduction on weekly films (braced cases) | | 3 | 6 to 8 weeks | Brace until union (8 to 12 weeks) for non-operative cases | Progressive active ROM; begin strengthening as union progresses | | 4 | 8 to 16 weeks | Union expected; night splint only if needed | Strengthening; graded return to function; contact or manual work once radiographically united | Most patients return to light activity early; heavier loading and contact or manual work are deferred until radiographic union (commonly 10 to 16 weeks). Radial nerve palsy rehabilitation. Fit a dynamic or static wrist and finger extension (cock-up) splint to prevent a flexion contracture while awaiting recovery, maintain passive ROM of the wrist and fingers, and monitor with serial examination — an advancing Tinel's sign down the forearm signals regeneration. EMG/NCS at about 6 weeks and 3 months tracks reinnervation; the first sign of recovery is usually return of brachioradialis and wrist extension, then finger and thumb extension. If there is no recovery by 3 to 4 months or EMG shows no reinnervation, explore; if the nerve is not reconstructable, plan tendon transfers (for example PT to ECRB, FCR or FCU to EDC, and PL to EPL).

How humeral shaft fractures are described. The diaphysis is the segment between the proximal and distal metaphyses, and fractures are classified first by anatomic level (proximal, middle, or distal third) and by pattern (transverse, oblique, spiral, comminuted, or segmental). The AO/OTA alphanumeric system (a 12- prefix) is used principally for research and registry coding. Two patterns carry disproportionate exam weight because of their relationship to the radial nerve: the Holstein-Lewis distal-third spiral fracture (classically associated with radial nerve palsy as the nerve pierces the lateral intermuscular septum) and the distal-third transverse fracture (the classic nonunion pattern). The humerus is a non-weight-bearing bone surrounded by a generous soft-tissue sleeve, which is why functional bracing works so well and why substantial residual angulation is tolerated.

Key evidence. Sarmiento's large series established functional bracing as the standard non-operative treatment with high union rates and acceptable residual deformity, and the FISH randomised trial confirmed that bracing and plating give similar 12-month function in closed fractures (with a higher secondary-surgery rate for bracing). For radial nerve palsy, Shao's systematic review of over a thousand palsies found an overall prevalence of about 11.8 percent and no benefit to routine early exploration over expectant management for closed fractures. For the implant debate, the Heineman and Ouyang meta-analyses of randomised trials found fewer shoulder complications and lower reoperation with plating, and a higher rate of transient iatrogenic radial nerve palsy at open plating — so the device is matched to the fracture and patient. The An series showed that anterolateral MIPO with an extraperiosteal submuscular plate gives a high union rate with low radial nerve injury when the distal window is respected.