What are the types of metatarsal fractures?
Fractures are divided into acute fractures, which occur at the time of injury, and stress fractures, which accumulate from repeated loads. The second, third and fifth bones are most often affected. A fracture of the base of the fifth metatarsal bone is considered separately: in one of its zones the blood supply is worse, and such a fracture often heals slowly, requiring prolonged unloading or fixation with a screw. A stress fracture is common among runners, dancers, military personnel, and people who dramatically increase their walking distance, and is not visible on regular x-rays for the first few weeks.
- Acute fracture from a direct blow or falling object
- Avulsion fracture of the base of the fifth metatarsal
- Fracture in an area with poor blood supply to the fifth bone
- Stress (marching) fracture of the second and third bones
- Fracture dislocation in the Lisfranc joint - severe injury to the middle of the foot
Causes and risk factors
Acute fractures are most often caused by a heavy object falling on the foot, running over a wheel, jumping from a height, or twisting a leg on an uneven surface. Stress fractures are associated with a mismatch between the load and the bone's ability to heal: a sharp increase in running volume, hard surfaces, worn-out shoes. The risk is increased by low bone density, vitamin D deficiency, nutritional disorders, foot deformities, and medications that affect bone turnover. Women who stop menstruating due to intense exercise are at particularly high risk.
- Heavy object falling on foot
- Turning your leg inward
- A sharp increase in running loads
- Inappropriate or worn shoes
- Osteoporosis and vitamin D deficiency
- Flat feet and high arches
Symptoms
With an acute fracture, pain occurs instantly, the foot quickly swells, bruising appears on the back and sole, and it is painful or impossible to step on the foot. Pressing directly over a broken bone causes sharp local pain - this sign helps to distinguish a fracture from a general bruise. With a stress fracture, the picture is different: the pain increases over weeks, intensifies during training and subsides with rest, the swelling is moderate and appears later. Continuing loads in this situation is dangerous - the crack can turn into a complete fracture with displacement.
- Pain when putting weight on the foot and when walking
- Swelling of the dorsum of the foot, bruise
- Point tenderness over the bone
- Crunch and deformation in severe fracture
- Gradually increasing pain from a stress fracture
- Lameness and gentle gait
Diagnostics
The main method is x-ray of the foot, usually in three projections, since the bones overlap each other and the fracture is easy to miss. If a Lisfranc joint injury is suspected, weight-bearing or CT scans are taken: this injury is often underestimated, and its consequences are severe. A stress fracture is not visible on x-rays in the first two to three weeks, so if the history is typical, an MRI is prescribed. A repeat image after 10–14 days also helps: by this time a bone callus will appear, confirming the diagnosis.
- X-ray of the foot in direct, lateral and oblique projections
- Repeat image after 10–14 days if in doubt
- CT scan for fracture dislocation and comminuted fracture
- MRI for suspected stress fracture
- Soft tissue ultrasound to evaluate ligaments and hematoma
- Screening for osteoporosis for recurrent fractures
Treatment and return to exercise
Non-displaced fractures are treated with unloading: rigid postoperative shoes, an orthosis or a plaster cast, and walking with crutches are prescribed for a period determined by the doctor. In the first days, an elevated position of the foot and cold through the fabric help. The operation is performed in case of significant displacement, multiple fractures, damage to the Lisfranc joint and fractures of the base of the fifth bone in athletes, when fast and reliable healing is important: the fragments are fixed with a screw, knitting needles or a plate. After fusion, the load is increased gradually, shoes with hard soles and, if necessary, insoles are selected. Athletes are allowed to return to running in stages to avoid recurrent fractures.
- Unloading the foot, walking on crutches
- Hard shoes, orthosis or cast for 4–8 weeks
- Elevated position and cold in the first days
- Osteosynthesis with a screw or plate during displacement
- Control shots before load release
- Gradual return to walking and running
- Correction of vitamin D deficiency and treatment of osteoporosis