What is the best course of treatment for a patient with an intra-articular fracture of the proximal 4th metatarsal?

Treatment of Intra-Articular Fracture of the Proximal 4th Metatarsal

For an intra-articular fracture of the proximal 4th metatarsal, initial treatment should be non-weight-bearing below-knee cast or boot immobilization for 3 weeks, followed by weight-bearing immobilization for an additional 3+ weeks, with mandatory surgical fixation (open reduction and internal fixation with plate and calcaneal autograft) if displacement exceeds 3mm, articular step-off develops, or conservative treatment fails to achieve healing by 6-8 weeks. 1, 2

Initial Diagnostic Evaluation

• Obtain standard three-view foot radiographs (anteroposterior, lateral, and oblique) to assess fracture displacement, articular involvement, and alignment 3
• Weight-bearing radiographs should be obtained if tolerable to assess joint stability and displacement under load 4
• CT without contrast is indicated if radiographs are equivocal regarding intra-articular extension, displacement magnitude, or joint congruity 5
• Specifically evaluate for metatarsus adductus deformity, which is associated with lateral metatarsal stress fractures and may influence treatment 2

Treatment Algorithm Based on Fracture Characteristics

Non-Displaced Intra-Articular Fractures (Displacement <3mm, No Articular Step-Off)

• Begin with non-weight-bearing below-knee cast or boot immobilization for 3 weeks 1
• Transition to weight-bearing cast or boot for an additional 3+ weeks 1
• Critical monitoring point: Obtain repeat radiographs at 3 weeks to detect delayed displacement that would mandate surgical conversion 6
• Obtain final radiographs at time of immobilization removal (6-8 weeks total) to confirm healing 6
• Warning: Proximal 4th metatarsal fractures heal significantly slower than typical lesser metatarsal shaft fractures, with healing often taking 2-8 months even with appropriate treatment 1

Displaced Intra-Articular Fractures - Mandatory Surgical Indications

Surgical fixation is required if any of the following criteria are met:

• Displacement exceeds 3mm 6, 5
• Any articular step-off or loss of joint congruity 6, 5
• Fracture involves >33% of the articular surface 5
• Joint instability or incongruity on weight-bearing films 5
• Interfragmentary gap >3mm 5
• Failure to heal after 6-8 weeks of conservative treatment 1, 2

Surgical Technique for Athletes or Failed Conservative Treatment

• Preferred method: Open reduction and internal fixation with plate and screws plus calcaneal autograft 2
• This approach achieves radiographic healing and return to sports at an average of 12 weeks post-surgery in athletes 2
• Percutaneous pinning is suitable for most lesser metatarsal fractures but may be inadequate for complex intra-articular patterns 7
• Open reduction with plate fixation is preferred for fractures with joint involvement and multiple fragments 7

Critical Pitfalls to Avoid

• Do not underestimate healing time: Proximal 4th metatarsal fractures behave similarly to proximal 5th metatarsal Jones fractures, with propensity for delayed union and nonunion 1, 2
• Do not allow early weight-bearing: Patients may remain symptomatic even after 3 months of rest and immobilization if weight-bearing is initiated prematurely 1
• Do not miss displacement on follow-up: Approximately 14.7% of immobilized fractures develop complications including delayed displacement 6
• Do not treat displaced intra-articular fractures conservatively: This leads to joint incongruity and post-traumatic arthritis 5

Expected Outcomes

Conservative Treatment

• Healing typically requires 2-8 months, longer than typical metatarsal shaft fractures 1
• Some patients remain symptomatic despite 3+ months of appropriate immobilization 1
• Immobilization-related complications (skin irritation, muscle atrophy) occur in approximately 14.7% of cases 6

Surgical Treatment in Athletes

• All patients achieve radiographic healing prior to return to activity 2
• Average return to sports at 12 weeks post-surgery 2
• AOFAS Midfoot scores improve from average 55 preoperatively to 94 postoperatively 2

Post-Treatment Rehabilitation

• Early active motion exercises should begin as soon as fracture stability allows to prevent stiffness 5
• Progressive weight-bearing should be advanced based on radiographic evidence of healing, not just symptom resolution 3
• Functional support with appropriate footwear facilitates return to activities 4
• Avoid prolonged immobilization beyond what is necessary for healing, as this leads to stiffness and muscle atrophy requiring extended rehabilitation 4