Metatarsal shaft and neck fractures

The metatarsal heads share the load of the forefoot: the first carries about a third of the forefoot load through its two sesamoids. In the central metatarsals what matters is displacement in the sagittal plane — a head that drops plantarwards becomes a painful callosity, one that rises transfers load to the neighbours. Rotation and shortening are tolerated better. The fifth metatarsal base is a separate entry.

Mechanism

Direct crush (dropped object, run over) usually breaks several adjacent shafts transversely; twisting with a fixed forefoot gives spiral fractures. Repetitive loading (marching, running, a new training load, low bone density) gives stress fractures, typically of the second and third neck or distal shaft — the march fracture.

Clinical findings

• Localised swelling and tenderness along the shaft; pain on axial compression of the toe.
• Crush injuries: skin condition and compartment syndrome of the foot (pain out of proportion, tense dorsum).
• Stress fracture: activity-related forefoot pain over weeks, local swelling; ask about training changes, amenorrhoea and diet (relative energy deficiency).

Imaging

• AP, oblique and lateral of the foot.
• Lateral (or oblique) to judge plantar displacement of the heads.
• Suspected stress fracture with normal films: MRI or repeat X-ray in 2–3 weeks.

• AP, oblique and lateral of the foot. The lateral is needed to judge sagittal (plantar) displacement of the heads, but the bones overlap: an oblique helps.
• March fracture: early films are normal in most; periosteal callus appears after 2–3 weeks. MRI (bone oedema) or bone scan confirms it early.
• Several metatarsal fractures or a fracture of the second metatarsal base: look for a Lisfranc injury.

Classification

87.1–87.5

Metatarsal by number (87.1 first to 87.5 fifth).

.1 / .2 / .3

Proximal end, diaphysis, distal end (neck and head).

A / B / C

Shaft: simple, wedge, multifragmentary. Ends: extra-articular, partial articular, complete articular.

Stress fracture

Usually 87.2–87.3 distal shaft or neck; fifth metatarsal proximal shaft stress fractures behave differently (see Jones).

Types shown in 3D

Second metatarsal shaft

Simple transverse or short oblique shaft fracture (87.2.2A): the distal fragment tips plantarwards and shortens slightly. Treated in a stiff shoe unless sagittal angulation exceeds about 10° or translation 3–4 mm.

Multiple shafts (2nd–4th)

Crush injury breaking several neighbouring shafts: the transverse arch loses its support and the heads drop. More often fixed (K-wires or plates); watch the skin and compartments.

Neck (3rd)

Metatarsal neck fracture (87.3.3A): the head displaces plantarwards and proximally and can become a painful prominence under the forefoot. Reduce and pin if clearly displaced.

First metatarsal shaft

87.1.2: the first ray carries about a third of the forefoot load and controls the sesamoids, so displacement, shortening or rotation are not accepted: plate or screw fixation.

March (stress) fracture

Fatigue fracture of the distal shaft or neck of the second (or third) metatarsal after unaccustomed walking or running. The line is a hairline; callus appears at 2–3 weeks. Rest in a stiff shoe and treat the cause.

Treatment

Central metatarsals (2nd–4th), acceptable alignment

Most are treated without surgery: stiff-soled shoe or walking boot, weight bearing as tolerated, 4–6 weeks. Accept rotation and mild shortening.

Central metatarsals, displaced

Fix when the sagittal angulation exceeds about 10° or the translation 3–4 mm, especially with several adjacent fractures (the transverse arch collapses): closed or open reduction and antegrade or retrograde K-wires, or small plates.

First metatarsal

Undisplaced: cast or boot. Any displacement, shortening or articular step: ORIF with a plate or screws, because the first ray carries much of the load and controls the sesamoids.

March (stress) fracture

Rest from the provoking activity, stiff shoe or boot with weight bearing as tolerated for 4–6 weeks, then a graded return. Treat the cause: training errors, footwear, vitamin D and bone health, energy availability.

Aftercare

Weight bearing as symptoms allow in most; after fixation, heel weight bearing in a postoperative shoe for 6 weeks. K-wires out at 4–6 weeks.

Complications

• Plantar malunion: transfer metatarsalgia and callosities
• Dorsal malunion: transfer lesions under adjacent heads
• Non-union (rare in central shafts)
• Compartment syndrome after crush
• Recurrence of stress fractures if the cause is not addressed