Is geriatric patient satisfaction related to pre-injury osteoarthritis after locking plate fixation for distal femoral fractures?

Objectives In elderly patients, distal femoral fractures are mostly related to osteoporosis. Osteoporosis weakens the supracondylar region, resulting in complex intra-articular fractures and metaphyseal comminution. The prevalence of knee osteoarthritis (OA) in this age group may affect the final functional outcome after fixation. The study assessed the relationship between pre-injury OA stage and postoperative functional outcome after fracture fixation by monoaxial lock plates. Patients and methods A prospective study was conducted between November 2016 and May 2019. A total of 38 cases of distal femoral joint fractures, including 18 extra-articular fractures (group-1; 33-A) with an average age of 67.6 ± 4 years and 20 cases of complete articular fractures (group-2; 33-C) with mean age of 69.2 ± 2.9 years, were included. Domestic fall was the mode of trauma, and the fractures were treated with a monoaxial distal femoral locked compression plate through a mini-invasive incision. Pre-injury knee conditions were assessed according to Knee Injury and Osteoarthritis Outcome Score. The final 1-year outcome was assessed using the Knee Society Score systems. Results In extra-joint fractures, the mean healing time was 17.6 ± 1.1 weeks (16–20 weeks), and in the complete articular fractures, the mean healing time was 23 ± 2.3 weeks (20–30 weeks). Complications were recorded as a single case of nonunion development that needed revision and grafting, and the union was achieved 20 weeks later. Joint line pain was observed in 15 (39%) of all patients. The final result of the Knee Society Score system for group 1 fractures was 74.7 ± 8.3 (60–90), and the mean for group 2 was 65.2 ± 9.5 (50–80). P value was less than 0.001. A clear correlation between the degree of pre-injury OA (Knee Injury and Osteoarthritis Outcome Score) and the final functional outcome (P=0.7) was identified, regardless of the severity of the fracture. Conclusion Monoaxial locking plate fixation for distal femoral fractures in the elderly population is a stable construct to stabilize this osteoporotic bone. It allows sound healing; however, the functional outcome is affected by the pre-injury joint OA.