The anterior stress fracture of the tibia: an atrophic pseudoarthosis?

Histopathological examination of biopsies from the fracture site in two cases of anterior stress fractures of the tibia demonstrated no bone remodelling activity, absence of inflammatory cells, extensive fibrotic infiltration and local avascular bone necrosis. The biopsies were taken peroperatively from two elite soccer players who earlier had to stop training due to severe exertional pain. When non-operative treatment failed to heal the fractures within 1 year and 6 months, respectively, surgery was performed in order to stabilize the fractures. Both subjects were relieved from exertional pain within 6 months of surgery. Consecutive radiographs showed the pattern of direct healing and 8 months postoperatively confirmed complete healing without callus formation. Both elite soccer players returned to pre-injury activity level. We suggest that the excessive fibrotic tissue ingrowth and hypovascularity under repetitive stress causes the delayed healing and histopathological signs similar to an atrophic pseudoarthosis. Treatment should consequently consider the pseudoarthrotic character of the anterior stress fracture of the tibia.