The Outcome of Fixing Distal Femur Periprosthetic Fracture around Total Knee Replacement using a Locking Plate Non-Contact Bridging (NCB)

INTRODUCTION: Surgical fixation of peri-prosthetic distal femur fractures around knee replacements poses a challenge, especially in frail patients, with variable outcomes reported in the literature. This study looks at the outcomes of a consecutive series of patients presenting with such fractures and treated by using a locking plate fixation. MATERIALS AND METHODS: A total of 21 consecutive patients who were admitted to our trauma unit over 31 months and underwent fixation with the Non-Contact Polyaxial Locking plate system were retrospectively identified and their acute treatment with follow-up outcomes were analysed. RESULTS: The mean age was 81 years and 71% were in ASA grades 3 and 4. Fracture morphologies were classified as per the Su classification, yielding 8 (38%) classified as Su one, 4 (19%) as Su two, and 9 (43%) as Su type three. Postoperatively, 2 patients (9.5%) died due to hospital-acquired pneumonia, and another 2 patients (9.5%) developed wound infections necessitating further return to theatre. Additionally, 2 (9.5%) patients had distal femoral replacements due to non-union. Mean discharge time was 28 days with 12 patients (55% of patients) starting protected weight-bearing six weeks after surgery. CONCLUSION: The incidence of morbidity, mortality was significant and re-operation was required in patients treated as described, and these were partly attributed to the patient’s average age and the pre-existing comorbidities. Significant variations were noted in the time to discharge, rehabilitation, and time to achieve fracture union. However, the majority of fractures did eventually unite. Patients with comminuted fractures and insufficient bone stock are more likely to progress to non-union and end up requiring revision knee arthroplasty.