Early femoral condyle insufficiency fractures after total knee arthroplasty: treatment with delayed surgery and femoral component revision

Abstract

Background: Periprosthetic fracture following total knee arthroplasty (TKA) is usually associated with a traumatic event and typically treated with fracture fixation techniques. However, we report on a series of patients with early atraumatic condyle fractures that occurred as a result of insufficiency of the unloaded preoperative femoral condyle treated with delayed reconstruction.

Methods: We retrospectively reviewed a series of 7 patients who sustained femoral condyle fractures following TKA and evaluated risk factors for insufficiency.

Results: There were 6 females and 1 male with an average age of 65.5 (range, 63-75) years and an average body mass index of 29.4 (range, 27-32). Fracture occurred on average 24.9 days from the index surgery and secondary to a low energy mechanism. Five patients had valgus alignment (mean, 15.2°) preoperatively and sustained fracture of the unloaded medial femoral condyle. Two patients had varus alignment (mean, 7.0°) preoperatively and both fractured the unloaded lateral condyle. One patient underwent early intervention requiring distal femoral replacement secondary to femoral bone loss. The remaining 6 patients underwent delayed surgery for an average of 6 weeks to allow for fracture healing followed by femoral component revision. At last follow-up (average, 48.5 months), 1 patient required a tibial component revision; however, no revision of the femoral component was required.

Conclusions: Early femoral condyle insufficiency fractures following TKA may be a risk in females with poor bone quality and preoperative valgus alignment. Delayed surgery and femoral component revision is a treatment strategy that prevented the need for other tertiary reconstruction.

Keywords: Delayed treatment; Insufficiency fracture; Periprosthetic fracture; Total knee arthroplasty.

Figure 1

(a) Preoperative anteroposterior (AP) knee radiograph demonstrating valgus alignment. (b) Postoperative AP radiograph demonstrating a medial femoral condyle fracture.

Figure 2

(a) Preoperative AP knee radiograph demonstrating varus alignment. (b) Postoperative AP radiograph demonstrating a lateral femoral condyle fracture.

Figure 3

(a) Delayed surgery (avg. 6 weeks) for initial fracture healing. (b) Femoral component revised with a stemmed implant and femoral augments.

Figure 4

Intraoperative images illustrating the mechanism of failure seen with insufficiency and impaction of the unloaded condyle.