TIBIAL SHAFT

Tibial stress fractures are common The earliest manifestation is 'Shin Splints' which can have normal imagng or show nly vague non specific soft tissue oedema They are graded as: • Grade 1 periosteal bone oedema with normal marrow signal

• Grade 2 marrow oedema on fluid sensitive sequences • Grade 3 marrow oedema also visible on T1 images • Grade 4a intra cortical signal change • Grade 4b linear cortical fracture line

NAVICULAR

Stress fractures of the navicular are common in track and field athletes Compression of the medial column is thought to underlie the injury by biomechanically A sagittal orientation is typical The central part of the bone is typically involved

There are 3 grades • Grade 1 involves the dorsal cortex only • Grade 2 extends into the bone • Grade 3 involves both dorsal and plantar cortices

X-rays are frequently negative MRI and CT are more useful for diagnosis They can be difficult to treat and some require surgical stabilisation

METATARSAL

Metatarsal stress fracture should be considered in the differential diagnosis of Morton's neuroma or Freiberg's disease X-rays are commonly used initially but are frequently negative or subtle findings are overlooked Ultrasound can detect the early peri osteal changes

MRI is more sensitive for bone oedema.

OS CALCIS

Stress fractures of the os calcis occur due to opposition between weight-bearing heel strike and the pole of the Achilles tendon Symptoms can mimic Achilles tendinopathy The posterior tuberosity is the most common location Stress fractures and other bones not infrequently occur simultaneously

OTHERS

Other locations where stress fractures occur include • The proximal part of the 5th metatarsal • The base of the 2nd 3rd and 4th metatarsals • The medial malleolus

• The cuboid and cuneiform bones