Periprosthetic fractures of the knee: puzzle pieces.

Periprosthetic fractures associated with total knee arthroplasty occur intraoperatively or postoperatively. The parameters that determine the treatment are stability of the fracture and the implant, site of the fracture, and bone quality. Intraoperative fractures, if undisplaced and stable, can be managed by protected weight bearing and motion. If displaced, they are treated by internal fixation and a stem. Postoperative fractures, if undisplaced and stable, can be managed by restricted weight bearing and motion. If the fracture is displaced, in association with a stable implant, management is by internal fixation. If the fracture is associated with an unstable implant, then a revision with a stemmed component must be performed. If there is associated loss of bone stock, then augments or structural grafts may be necessary.