Periprosthetic fractures after total knee arthroplasty

Abstract

Periprosthetic fractures of the femur, tibia, or patella around a knee replacement are relatively uncommon. However, when these fractures occur, they are associated with considerable discomfort and disability. These fractures can be difficult to treat, and the rate of complications is high, ranging from 25% to 75% for both operative and nonoperative treatment.1,2 The Mayo Clinic Joint Registry documented 573 periprosthetic fractures following 19810 primary and revision knee replacement operations for an incidence of 2.8%.3 Following primary total knee arthroplasty (TKA), the incidence of periprosthetic fracture was 2.3%, and after revision TKA, the incidence of periprosthetic fracture was 6.3%.3 The reported incidence of periprosthetic distal femur fractures ranges from 0.3% to 2.5%.4 The prevalence of proximal tibial fractures is less than the distal femur. Thirty-two tibia fractures around knee replacements were reported from 1970 to 1992,5 and the prevalence has been reported from 0.4% to 1.7%.1 The incidence of periprosthetic patellar fractures has been reported at 0.05% when the patella is not resurfaced,6 and with patella resurfacing, the incidence ranges from 0.2% to 21%.6-21 The Mayo Clinic series documents 85 patella fractures out of 12464 consecutive TKAs, for an incidence of 0.68%.21 During the next decade, it is likely that the number of TKA operations in the United States will increase. The population is growing and aging; the prevalence of arthritic knees is increasing; and the success of knee replacements in patients of all ages is well documented.22 The volume of TKA operations is predicted to nearly double by 2030 to 474319 knee replacement operations.23 Considering that elderly patients are having more knee replacements, these patients are maintaining active lifestyles, and elderly patients have risks of osteopenia and falls, it is reasonable to predict an increase in periprosthetic fractures around knee replacements in the next decade. An understanding of several factors involved with periprosthetic fractures can help in prevention, diagnosis, and treatment of these fractures and their potential complications. These factors include deformity, osteoporosis and osteopenia, rheumatoid arthritis, steroid use, neuromuscular disorders, previous surgery, revision surgery, surgical technique, component positioning, component design, stress risers from screw holes, and osteolysis.24 Major concerns with treatment of these fractures are timing of the fracture (intraoperative or postoperative), type of fracture (condylar, intercondylar, supracondylar), stability of component fixation, and the activity and medical condition of the patient. In this chapter, we discuss fractures of the femur, proximal tibia, and patella adjacent to a total knee arthroplasty. The discussion of fractures is subdivided by anatomic location and whether they occur intraoperatively or postoperatively. Postoperative fractures can be further divided into traumatic and stress-related fractures. Intraoperative fractures occur less often than postoperative fractures, and they are more common with revision TKA operations than during primary total knee arthroplasty. These fractures are often minimally displaced and lack extensive soft tissue trauma. If recognized they can be adequately stabilized, and neither the rehabilitation nor the outcome need be significantly impacted. © 2005 Springer Science+Business Media, Inc. All rights reserved.