Stress fracture of the lateral metatarsals following double-stem silicone implant arthroplasty of the hallux metatarsophalangeal joint.

Stress fractures of the lateral metatarsal bones occur frequently and are most commonly seen following repetitive trauma. However, such fractures rarely occur after reconstructive operations involving the hallux metatarsophalangeal joint. The authors report four patients who developed a lateral metatarsal stress fracture during the first year following use of a double-stem silicone implant to reconstruct the hallux and, in addition in the case of one patient, the second metatarsophalangeal joint. An analysis of all these patients established the incidence of this complication to be 3%. The etiology of these fractures appears to be an overloading of the lateral metatarsals secondary to some shortening of the hallux metatarsal or in reestablishing motion to the hallux metatarsophalangeal joint. All fractures healed without complication and did not result in further forefoot symptoms or deformities. However, this complication should be suspected when lateral metatarsalgia develops following silicone implant arthroplasty because roentgenograms initially may be normal.