RESUMO
BACKGROUND: Intraoperative periprosthetic fracture (IF) is an under-reported complication in primary total knee arthroplasty (TKA). This study aimed to audit the outcomes and complication rates in patients encountering IF during primary TKA and propose a new classification for its management. METHODS: A nested case-control study was performed at a tertiary referral hospital where 50 patients encountering IF during primary TKA operated by a single surgeon team between January 2016 to May 2021, were compared with 150 (3:1) age-, gender- and implant-matched patients not encountering IF. Demographic data, risk factors, outcomes and complications of both groups were compared at a minimum follow up of 1 year. RESULTS: The incidence of IF was 0.45%, with 44 fractures in the femur (88%), six (12%) in the tibia and none in the patella. Medial collateral ligament avulsion fracture (54.54%) in the femur and medial plateau fracture (66.66%) in the tibia were the most common fracture types. At final follow up, the fracture group had higher rates of 90-day re-admissions (8% vs. 2.66%, P = 0.095), deep infection (4% vs. 0.66%, P = 0.15) and revisions (6% vs. 1.33%, P = 0.06). The mean Knee Society Score was not significantly different between the two groups (152.22 ± 9.25 vs. 161.68 ± 11.22, P = 0.642) with union being achieved in all but one patient at a mean duration of 9.6 weeks. CONCLUSIONS: Patients with severe and fixed deformities have a higher risk for IF. The occurrence of fracture and the complexity of surgery equally contribute to the higher complication rates. Appropriately managed fractures have comparable functional outcomes.