Periprosthetic fractures after total knee arthroplasty.

PURPOSE

To evaluate outcome in 20 patients treated for periprosthetic fractures after total knee arthroplasty (TKA).

METHODS

Records of 14 women and 6 men aged 45 to 85 (mean, 67) years who underwent operative (n=18) or conservative (n=2) treatment for periprosthetic fractures of the supracondylar femur (n=15), patella (n=3), and tibia (n=2) following minor falls (n=18) or high-velocity injury (n=2) were reviewed. The mean time from TKA to fracture was 43 (range, 14-98) months. Of the 15 supracondylar femoral fractures, 2 were managed with immobilisation in a long leg cast, 11 with internal fixation using locked compression plating, and 2 with revision arthroplasty. All 3 patellar fractures were managed with tension band wiring. Both tibial fractures were managed with revision arthroplasty. Radiographic and functional outcomes (the Knee Society scores) were assessed.

RESULTS

The mean follow-up was 35 (range, 24-48) months. All fractures healed after a mean of 15 (range, 12-38) weeks. One patient had delayed union. Postoperative alignment was satisfactory in all patients except one (with 5º varus). The mean tibiofemoral angle was 4º valgus. The mean range of motion was 98.5º. The mean Knee Society knee score was 85 (range, 75-89) and the functional score was 76 (range, 70-85). No patient had implant failure, loss of reduction, deep infection, deep vein thrombosis, or pulmonary embolism.

CONCLUSION

The locked compression plate is effective in managing periprosthetic femoral fractures. Periprosthetic patellar and tibial fractures are uncommon. The latter often warrant revision arthroplasty owing to the loose implant.