Arthroscopy Within Three Months Prior to Unicompartmental Knee Arthroplasty Is Associated With an Increased Rate of Periprosthetic Joint Infection.

Background: Arthroscopy remains a commonly performed procedure in patients who have meniscal or other osteochondral pathology prior to ultimately being indicated for unicompartmental knee arthroplasty (UKA). The purpose of this study was to examine the timing of knee arthroscopy prior to UKA and its association with 2-year periprosthetic joint infection (PJI) rates and medical and surgical complications.

Methods: Patients undergoing UKA who had history of ipsilateral arthroscopy within 2 years prior to the UKA were identified in a national insurance database. A control cohort of propensity matched patients who did not have a history of arthroscopy was identified. Study cohorts were established based on timing of the arthroscopic procedure: 0 to 3, 3 to 6, 6 to12, and 12 to 24 months prior to UKA. Patients were included if they had 2-year postoperative follow-up after UKA. The 90-day rates of postoperative medical and 2-year surgical complications were recorded. Multivariate analysis was conducted to account for confounding variables and covariates.

Results: A final cohort of 3,471 patients met inclusion criteria. Patients undergoing UKA within three months of the arthroscopic procedure demonstrated a higher incidence of PJI when compared to the control cohort (3.30 versus 1.12%, P = 0.012). In addition, there was an increased rate of periprosthetic fracture observed in those undergoing UKA within three months of arthroscopy when compared to the control (1.10 versus 0.20%, P = 0.010).

Conclusions: Patients undergoing ipsilateral arthroscopy within three months of a UKA demonstrated a nearly 3-fold increased incidence of PJI when compared to the control. There was no increased incidence of PJI when UKA was staged greater than three months after arthroscopy. These findings provide insight for preoperative considerations for arthroplasty surgeons in this patient population.

Level Of Evidence: Level III, retrospective comparative study.