There are many injuries and conditions that can cause pain in the midfoot. By far the most feared over use injury for athletes is a stress fracture of the navicular bone. This injury commonly occurs in sports that involve plenty of running, jumping and hurdling and usually requires a much longer healing time than other stress fractures.
The middle portion of the navicular is relatively avascular (poor blood supply) and thus heals poorly when injured causing delayed union of the bone. Navicular bone stress occurs when exposed to repetitive compressive forces between the medial cuneiform and talus bones. Overuse and training errors, such as a dramatic increase in the intensity, frequency and duration of training, along with poor footwear and poor biomechanics, can contribute to excessive stress on the navicular bone.
Navicular stress fractures are clinically characterised by a slow onset of pain (usually ache) associated with activity such as running or jumping. It can abate with rest, though ongoing pain at night is not uncommon. The middle, avascular, region of the navicular bone is tender on palpation.
Diagnosis of a navicular stress is confirmed using x-ray (this will commonly not show a stress fracture but is handy to rule out other causes of pain) and isotopic bone scan or MRI.
Treatment of a navicular stress reaction is weightbearing rest in an immobilisation walker until the symptoms have resolved, followed by graduated return to activity. However, if scans confirm a true navicular stress fracture, the treatment is strict non-weight bearing immobilisation for 6 to 8 weeks. If the navicular is still painful at the end of this period, a further 2 weeks of non-weightbearing immobilisation is recommended. In both cases, return to sport should be graduated slowly and with the aid of appropriate footwear, strengthening and possibly orthotic support for the feet to prevent re-injury.