Indirect forces and patella fracture after anterior cruciate ligament reconstruction with the patellar ligament. Case report.

Patella fracture is either an infrequent or underreported complication after anterior cruciate ligament (ACL) reconstruction using a portion of the patellar ligament. Patella fracture pattern has been related to the mechanism of injury. Direct fractures resulting from impaction forces delivered to the patella are typically stellate or comminuted. Indirect fractures resulting from tensile stresses applied across the extensor mechanism typically are displaced transverse disruptions. After ACL reconstruction using a portion of the patellar ligament, Y-shaped stellate fractures can occur. Fracture pattern seems related to the time elapsed since the harvest; stellate fractures occur following stumbles or slips without direct injury early in the postoperative period while transverse fractures occur late. This article describes two cases of patella stellate fractures that occurred in patients who underwent ACL reconstruction using patellar graft.