Abstract
We report a rare case of late knee locking after an open knee injury in a polytrauma patient with a pelvic fracture and a contralateral femoral artery injury. Once the life and limb threatening injuries were addressed, debridement and washout of the knee wound was performed. X-rays and subsequent CT revealed only an undisplaced patella fracture. The patient presented 6 months later to a knee surgeon with recurrent locking. An arthroscopy was performed and a 10 mm plastic soft drink bottle cap was retrieved leading to the immediate resolution of symptoms without complications.Open knee injuries require thorough debridement washout and joint assessment. Late locking should raise the suspicion of an intra-articular loose or foreign body. Arthroscopy is an excellent first line tool in the diagnosis and late management of this unusual problem.