Jones Fracture

This is a fracture of the fifth metatarsal at the junction of the metaphysis and the diaphysis, in the area where the fourth and fifth metatarsal bases articulate, about 1.5 to 3 cm distal to the tuberosity. The lesion lies in a vascular watershed, where the nutrient artery from the mid-diaphysis and the metaphyseal vessels from the proximal end meet. Healing is therefore slow and unreliable.

It accounts for under 5% of fifth metatarsal fractures and is common in athletes in football, basketball and running. Mechanism: acute adduction force on a plantarflexed forefoot, or repetitive stress, and many have prodromal lateral foot pain for weeks before a complete fracture. Risk factors are a cavovarus foot, vitamin D deficiency, bisphosphonate use, a high first-to-fifth metatarsal angle and sudden increases in training.

The fracture appears in three forms on radiographs: acute (sharp edges, no sclerosis), delayed union (widened line with sclerosis at the margins) and nonunion (obliterated medullary canal). Nonoperative treatment gives delayed or nonunion in up to 25 to 30%, and refracture occurs in 7 to 28% after early return to sport or hardware removal.

• Lateral midfoot pain over the fifth metatarsal base, worse with push off and cutting
• Swelling and bruising over the lateral border, with a history of preceding vague lateral foot pain in a stress fracture
• Tenderness distal to the tuberosity and pain with resisted eversion
• Cavovarus alignment with a high arch and heel varus
• Red flags: bilateral pain, displacement, previous fracture at the same site, and a failing healing course

• Radiographs (anteroposterior, lateral and oblique of the foot): transverse or short oblique fracture within 1.5 cm of the tuberosity at the fourth-fifth intermetatarsal joint, with sclerosis, cortical thickening and a widened line in chronic cases.
• CT at 6 to 8 weeks to assess bridging bone and plan surgery.
• MRI for stress reaction with a normal radiograph.
• Metabolic evaluation: serum 25-hydroxyvitamin D, calcium, phosphate, parathyroid hormone, and bone density in recurrent cases.

Differentials: tuberosity avulsion, diaphyseal stress fracture, os vesalianum, peroneus brevis tendinopathy, cuboid fracture, lateral ankle sprain.

Acute, undisplaced, in a non-athlete: non-weight-bearing short leg cast for 6 to 8 weeks, then a boot with progressive loading, with radiographs at 6 weeks. Union rate about 70 to 90%.

Athletes, displaced fractures, delayed union and nonunion:

• Intramedullary screw fixation: solid, partially threaded 5.5 to 6.5 mm screw (the widest that fits the canal, 4.5 mm minimum), inserted from the tuberosity along the axis of the shaft under fluoroscopy, with the foot on a bump.
• Bone graft (iliac crest or calcaneal autograft) and plantar plating for nonunion, revision and refracture. Remove sclerotic bone and open the canal.
• Correct cavovarus with a lateralizing calcaneal osteotomy or dorsiflexion osteotomy of the first metatarsal.
• Cefazolin 2 g IV before incision. Enoxaparin 40 mg SC daily while non-weight-bearing.
• Postoperative: non-weight-bearing 2 weeks, boot with protected weight bearing for 4 to 6 weeks, return to running at 8 to 12 weeks once radiographs show union, and sport at 3 to 4 months.

Bone health: cholecalciferol 2000 IU orally daily for at least 8 weeks if vitamin D is below 50 nmol/L, and calcium intake 1000 mg daily. A bone stimulator can be used for delayed union.

Analgesia: paracetamol 1 g orally every 6 hours and ibuprofen 400 mg orally every 8 hours with food for up to 7 days. Avoid NSAIDs for longer, which may impair healing.

Complications: refracture, nonunion, screw prominence, sural nerve injury, hardware pain and stiffness. Follow up at 2, 6 and 12 weeks, then 6 months. Counsel on a gradual return to training and footwear with a lateral arch support.