Knee: role and results of allografts.

The vast majority of periprosthetic fractures occur as the result of trauma. There are many predisposing factors for these factors, including osteopenia, neurologic disorders, medications, rheumatoid arthritis, previous arthroplasty, and infection. These same factors also increase the likelihood of fracture comminution, and the presence of poor bone quality makes fixation difficult and prone to failure.