Introduction
Periprosthetic femur fracture (PFF) is an increasingly common indication for revision arthroplasty following total hip arthroplasty (THA). There are fundamental differences between early PFFs that occur prior to osseointegration and those that occur later. Prior studies demonstrate that early aseptic THA reoperations increase the risk of periprosthetic joint infection (PJI), but are limited by the varying levels of severity of indications for reoperation. The objective of this study was to compare the rate of reoperation and PJI following PFFs that occur in the early postoperative period (<90 days following primary THA) to those that occur remotely (>90 days following primary THA).
Methods
A retrospective review of our institution’s joint registry identified 173 consecutive surgically managed PFFs between January 2008 and June 2020. Patients with an index procedure other than primary THA or conversion THA were excluded. Patients with cemented index stems, acetabular fractures, pathologic fractures, and extended trochanteric osteotomy were excluded. Baseline patient demographics, preoperative comorbidities, and postoperative outcomes were queried for all patients. Patients were assigned the “early” cohort if the PFF occurred within 90 days from the primary THA or the “late” cohort if they occurred following the initial 90 days. Univariate analysis identified differences in baseline patient demographics. Kaplan Meier analysis estimated survival probabilities.
Results
A total of 173 consecutive cases were identified, including 90 in the early and 83 in the late PFF cohort. Compared to the late cohort, the early cohort had a greater proportion of females (64.4% vs. 47.4%, p=0.025) and a greater proportion of index THA performed via direct anterior approach (12.9% vs. 1.8%, p=0.035), but no difference in mean age (68 ± 8 vs. 69 ± 12, p=0.12), American Society of Anesthesiology (ASA) classification (p=0.288), mean follow up (26.82 ± 26.77 vs. 30.98 ± 31.41, p=0.349), and index (p=0.139) and revision stem (p=0.697) manufacturer/model. PFF Vancouver classification did not vary between cohorts (p=0.105). There were more revisions for PJI following surgical treatment of early PFFs than late PFFs (11.2% vs. 0%, p=0.02). Compared to the early PFF cohort, the late PFF cohort had greater 1-year (91.2%, 95% confidence interval (CI): (83.1% - 100%) vs. 78.6%, 95% CI: (71.0% - 87.1%)) and 2-year (87.7%, 95% CI: (77.7% - 98.9%) vs. 75.7%, 95% CI (67.5% - 84.9%)) reoperation-free survival probability. There was a significant difference in reoperation-free survival curves between cohorts (p=0.04).
Conclusion
There is a higher incidence of reoperation and PJI following PFFs that occur within 90 days following primary THA, compared to PFFs that occur remotely. Efforts to prevent early PFF as well as subsequent infections remain paramount, including antiseptic/prophylactic irrigation and sterile field maintenance.