Periprosthetic fractures after total knee arthroplasty: an extensive review of its patterns, risk factors, treatment options, outcomes and correlation of its severity with the bone mineral density

Background: Periprosthetic fracture (PPF) around knee is a rare but debilitating complication after total knee arthroplasties. Methods: Retrospective analysis of 12,133 knee replacements done at a single centre from 2011-2024 was done to analyse incidence, risk factors, pattern, treatment and outcomes of PPF and correlation of its severity with the Bone mineral Density. Results: The incidence of PPF was 0.42% (femur=0.34%, tibia=0.07% and patella=0.01%). 51.6% were female patients. Mean age, BMI, CCI and follow up was 63.32 (22-89 years; SD=13.51), 30.6 (20.2-43.8; SD=3.9), 2.2 (1-4; SD=0.77) and 5.1 years (1-14 years; SD=4.29). Mean BMD was -1.78 (1 to -3; SD=0.69). Primary osteoarthritis was the diagnosis in 93.91% and PFC Sigma (Depuy, Johnson and Johnson) posterior stabilised prosthesis was used in 88% of the patients. The mean grade of anterior cortex notching (Tayside classification) was 0.39 (0-3, SD=0.12). Only female gender was a significant risk factor for PPF (OR=3.1; 2.31-3.97 at 95%CI; p value=0.01). There was no significant correlation between the BMD and the grade of fracture as per Lewis and Rorabeck, Su and Felix classifications (p values=0.77, 0.80 and 0.74 respectively). 33 PPFs (64.7%) were fixed with locking plates and 5 (9.8%) were revised to hinged prosthesis. 98% fractures united at mean 17.8 weeks and Mean KSS at 1 year was 144.77+/-2.08. 1 year mortality rate post PPF was 2%. Conclusions: While female gender is a significant risk factor for PPF, BMD does not correlate with its severity. Appropriate treatment option selected based on the general health of the patient, fracture pattern and implant stability results in good outcomes and less mortality.