Postresurfacing periprosthetic femoral neck fractures: nonoperative treatment.

Femoral neck fractures after total hip resurfacing procedures occur infrequently but require immediate orthopedic intervention. Historically, they have been treated by conversion to traditional total hip arthroplasty. However, to the authors' knowledge, no treatment algorithm has ever been described. The authors have directly treated or consulted on 13 cases of periprosthetic femoral neck fractures after metal-on-metal hip resurfacing arthroplasties that were successfully treated nonoperatively: all fractures healed with protected weight bearing, producing excellent clinical results. Two cases are described in detail, and the authors propose a classification system that can assist the orthopedist in choosing the treatment regimen. Type I fractures are nondisplaced and should be initially treated nonoperatively with a course of protected weight bearing. If successful, the overall success of the resurfacing should not be compromised. Partially displaced, or type II, fractures may heal with nonoperative management. However, if the components have shifted, it may affect the long-term durability of the arthroplasty and eventually result in premature conversion to a traditional total hip replacement. Depending on the position of the components, it may also have an effect on the ion generation potential of the metal-on-metal articulation. This treatment pathway can be undertaken only with a full and detailed explanation of all of the possible complications and outcomes with the patient. Completely displaced, or type III, fractures require immediate conversion to total hip arthroplasty.