CANNABIS USE INCREASES RISK FOR REVISION AFTER TOTAL KNEE ARTHROPLASTY.

As an increasing number of states begin to legalize marijuana for either medical or recreational use, it is important to determine its effects on joint arthroplasty. The purpose of this study is to determine the impact of cannabis use on total knee arthroplasty (TKA) revision incidence, revision causes, and time to revision by analyzing the Medicare database between 2005 and 2014. A retrospective review of the Medicare database for TKA, revision TKA, and causes was performed utilizing Current Procedural Terminology (CPT) and International Classification of Disease ninth revision codes (ICD-9). Patients who underwent TKA were cross-referenced for a history of cannabis use by querying ICD-9 codes 304.30-32 and 305.20-22. The resulting group was then longitudinally tracked postoperatively for revision TKA. Cause for revision, time to revision, and gender were also investigated. Our analysis returned 2,718,023 TKAs and 247,112 (9.1%) revisions between 2005 and 2014. Cannabis use was prevalent in 18,875 (0.7%) of TKA patients with 2,419 (12.8%) revisions within the cannabis cohort. Revision incidence was significantly greater in patients who use cannabis (p < 0.001). Time to revision was also significantly decreased in patients who used cannabis, with increased 30- and 90-day revision incidence compared to the noncannabis group (P < 0.001). Infection was the most common cause of revision in both groups (33.5% nonusers versus 36.6% cannabis users).Cannabis use may result in decreasing implant survivorship and increasing the risk for revision within the 90-day global period compared to noncannabis users following primary TKA.