What is the recommended care for a fractured proximal 5th metatarsal?

Management of Proximal Fifth Metatarsal Fractures

For proximal fifth metatarsal fractures, immobilize with either a CAM-walker boot or hard-soled shoe for 6-8 weeks with weight-bearing as tolerated, reserving surgical intervention for displaced fractures, delayed unions, or high-performance athletes requiring rapid return to activity. 1, 2

Initial Assessment and Diagnosis

• Obtain three standard radiographic views (anteroposterior, lateral, and oblique) with weight-bearing to confirm the diagnosis and assess fracture displacement 1, 3
• Apply the Ottawa rules to determine imaging necessity: radiographs are indicated if there is point tenderness at the base of the fifth metatarsal 1
• Consider CT imaging if surgical planning is needed for unstable or significantly displaced fractures to evaluate the true extent of osseous injury 1, 4

Classification-Based Treatment Algorithm

Zone 1 (Tuberosity Avulsion Fractures)

Non-displaced fractures:

• Treat conservatively with either a CAM-walker boot or hard-soled shoe for 6-8 weeks 2, 5
• Allow weight-bearing as tolerated based on pain level 3, 5
• The CAM-walker boot achieves faster radiographic healing (7.2 weeks vs 8.6 weeks) compared to hard-soled shoes, though clinical outcomes are equivalent 5

Indications for orthopedic referral:

• Displacement present 2
• Comminuted fractures 2
• Involvement of >30% of the cubometatarsal articulation surface 2
• Delayed union 2

Zone 2 (Jones Fractures - Acute Metaphyseal-Diaphyseal Junction)

Standard treatment:

• Non-weight-bearing short leg cast for 6-8 weeks achieves 72-93% union rates 6
• This represents the acute fracture occurring within 1.5 cm of the tuberosity at the fourth-fifth intermetatarsal facet 2, 6

Surgical option:

• Early intramedullary screw fixation is appropriate for high-performance athletes or patients unwilling to accept prolonged non-weight-bearing immobilization 7, 6
• All displaced fractures require surgical management 2

Zone 3 (Diaphyseal Stress Fractures)

• All Zone 3 fractures should be managed surgically with either closed axial intramedullary screw fixation or autogenous corticocancellous grafting 2, 6
• These represent the highest risk for nonunion due to poor blood supply in this region 3

Pain Management

• Initiate regular paracetamol (acetaminophen) as first-line analgesia 4
• Early fracture stabilization through proper immobilization provides the most effective pain relief 1
• Use opioids cautiously and sparingly, particularly in elderly patients or those with renal dysfunction 8, 4
• Avoid NSAIDs in patients with renal dysfunction or elderly patients 4

Rehabilitation Protocol

• Begin early physical training and muscle strengthening once initial pain subsides 1
• Progress to long-term balance training and fall prevention exercises 1
• Avoid prolonged immobilization beyond necessary timeframes to prevent stiffness and muscle atrophy 1, 4
• Average return to prior activity levels occurs at 8-10 weeks regardless of immobilization method 5

Follow-Up Schedule

• Obtain radiographs at 4,8, and 12 weeks to assess healing 5
• Continue follow-up until the patient is asymptomatic and able to return to prior activity level 5
• Consider MRI for persistent symptoms to evaluate for incomplete healing or stress fracture progression 4

Special Populations

Diabetic patients with neuropathy:

• Pay special attention to offloading the foot throughout treatment to prevent complications 1, 4
• Monitor closely for skin breakdown or Charcot changes 1

Common Pitfalls to Avoid

• Do not overlook the distinction between Zone 1,2, and 3 fractures, as treatment and prognosis differ significantly based on location and blood supply 2, 3
• Delayed union, muscle atrophy, and chronic pain are potential long-term complications if immobilization is either insufficient or excessive 1, 2
• The proximal fifth metatarsal has varied healing rates due to watershed blood supply, making Zone 2 and 3 fractures particularly problematic 3, 6