Stress fractures are tiny cracks in a bone. They're caused by repetitive force, often from overuse — such as repeatedly jumping up and down or running long distances. Stress fractures can also develop from normal use of a bone that's weakened by a condition such as osteoporosis.
Stress fractures are most common in the weight-bearing bones of the lower leg and foot. In feet the vast majority occur in the shafts of the four lesser metatarsals (particularly the 2nd metatarsal) which are proportionally long thin bones and therefore are more vulnerable to cracking than the first metatarsal – see diagrams below (the focal point of pain would be within the shaded area depending which metatarsal was affected).
Track and field athletes and military recruits who carry heavy packs over long distances are at highest risk ('March' fractures) but anyone can sustain a stress fracture. If you start a new exercise program, for example, you might develop stress fractures if you do too much pounding too soon.
Symptoms of Metatarsal stress fractures?
- Pain – At first, you might barely notice the pain associated with a stress fracture, but it tends to worsen with time. The tenderness usually starts at a specific spot and decreases during rest. Significant pain can be triggered by pressing the affected area on the top of the foot. Referred pain can radiate around the forefoot and into the sole but there is a specific ‘bulls eye’ spot detectable by pressing the the top of the foot hard.
- Swelling – the majority (not all) will exhibit localised swelling / puffiness around the painful area visible on the top of the foot.
- Inflammation – often localised inflammation is seen.
- Warmth – at some point there may be an increase in temperature over the area compared to the rest of the foot (can be subtle and not always detectable).
- Bruising – occasionally a bruise may be visible on top of the foot.
Diagnosis of Metatarsal stress fractures?
- History & Examination – a strong suspicion can be made clinically however a definitive diagnosis can only be confirmed with imaging.
- Imaging – Ultrasound, X-ray, MRI, – these forms of imaging would provide a definitive diagnosis. If the stress fracture is relatively recent and very fine then occasionally it can be missed and may need to be repeated. If there was a strong clinical suspicion of a stress fracture then we would normally advise our patients to have an Ultrasound scan with our ‘in house’ specialist musculoskeletal Sonographer to confirm the diagnosis.
Treatment of Metatarsal stress fractures?
- Rest – rest, rest, rest, and more rest! Identify and avoid causative factor(s) then rest. Where healing is slow or symptoms are particularly acute we would advise patients to wear an air boot (below) whenever possible for at least a month or two.
- Pain relief – Ibuprofen / paracetamol.
- Low Level Laser – often reduces healing time.
- Surgery – the vast majority will heal if the foot is rested for long enough, if however the symptoms become chronic we would advise repeat imaging and if we suspected the fracture was not healing then we would refer on to a foot & ankle Orthapaedic consultant or a Podiatric surgeon with regard to probable surgery. The surgeon would likely use internal fixation (screw) to secure the fracture.