Case in Point: Second Metatarsal Stress Fracture - Part I

Stress fractures of the metatarsals are a common overuse injury in athletes and dancers and are only second to tibial stress fractures in terms of incidence⁽¹⁾. Stress fractures of the metatarsals are also common in military recruits and in long-distance runners and team sport athletes who cover large mileages in training and competition.

It has been reported that 10%⁽²⁾ to 20%⁽³⁾ of stress fractures in athletes, and 23%⁽⁴⁾ of stress fractures in military recruits are located in the metatarsals. In terms of location, it is more common for the 2^nd and 3^rd metatarsals to suffer stress reactions and fractures in the shaft and the non-proximal end of the bone. Indeed, the second and third metatarsal account for 80–90% of all metatarsal fractures^{(1, 5, 6)}. By contrast, proximal fractures in the heads of the metatarsals are not common.

Case study

A 21-year-old elite football player who plays as an attacking midfielder presented with acute onset, right-midfoot pain sustained in a training session. He described a sudden clicking sensation on the dorsum of the midfoot over the 2^nd and 3^rd metatarsals. The injury was caused by a sudden change in direction. He was able to continue training for ten more minutes; however he noticed the pain in the foot was increasing. He denied any previous sensations of midfoot pain leading up to this injury and had spent the previous 11 weeks of pre-season training completely injury free. His rehabilitation followed the 3-phase process.

Upon examination, the footballer was tender upon palpating the dorsum of the foot over the heads of the 2^nd and 3^rd metatarsals. Pain was reproduced with walking on the toes and was also reproduced by squeezing the metatarsal heads together. The ‘piano key’ sign (grasping each toe individually and moving them in a plantar and dorsal direction) was pain free.

Based on these findings, it was suspected he had suffered either a subtle Lisfrancs injury or had injured the heads of the metatarsals, so an X-ray and MRI scan was requested to investigate further. The X-ray report was unremarkable. The MRI report however described bone oedema in the head of the 2^nd metatarsal and shaft of the 3^rd metatarsal, with a small fracture line evident in the head of the 2^nd metatarsal (see Figure 1 below). No injury to the Lisfrancs ligament was reported.

Based on these findings the footballer was immobilised in a moon boot and instructed to mobilise in a non-weight bearing manner for an initial three weeks. He was then reviewed at three weeks and instructed to commence graduated rehabilitation (this will be discussed at length in part II).