Elsevier

The Journal of Arthroplasty

Volume 34, Issue 8, August 2019, Pages 1667-1669
The Journal of Arthroplasty

Primary Arthroplasty
Cannabis Use Does Not Affect Outcomes After Total Knee Arthroplasty

https://doi.org/10.1016/j.arth.2019.04.015Get rights and content

Abstract

Background

The self-reported use of cannabis has increased since its recent legalization in several states. The primary purpose of this study is to report total knee arthroplasty (TKA) outcomes in patients using cannabis.

Methods

Seventy-one patients who underwent a primary unilateral TKA with minimum 1-year follow-up, who self-reported cannabis use, were retrospectively reviewed. The study period was from January 2014 to February 2018 at a single institution. Patients with a history of opioid consumption, alcohol abuse, tobacco, or illicit drug use were excluded. A matched control was conducted based on age, body mass index, gender, smoking status, and insurance type (surrogate of socioeconomic status) in patients with a unilateral TKA who did not report cannabis use. Outcome measures included Knee Society Scores (KSS), range of motion, Veterans RAND-12 mental and physical component scores. No preoperative differences were noted with these measures. Postoperative complications were recorded and reported.

Results

No difference in length of stay was noted between the users (46.9 hours ± 15.7) and nonusers (49.3 hours ± 20.4) (P = .464). In-hospital total morphine equivalents did not differ between the 2 groups (user = 137 ± 104 mg, nonuser = 146 ± 117 mg, P = .634). Postoperative range of motion did not differ between users (128.4° ± 10.4°) and nonusers (126.9° ± 7.5°) (P = .346). No mean differences in follow-up KSS (user = 180.1 ± 24.9, nonuser = 172.0 ± 33.9, P = .106) or total change (user = 61.7 ± 32.8, nonuser = 62.7 ± 30.7, P = .852) in KSS were noted. Likewise, no significant mean differences in Veterans RAND-12 (mental component scores: user = 54.8 ± 9.3, nonuser = 55.9 ± 8.79, P = .472; physical component scores: user = 48.3 ± 9.9, nonuser = 45.8 ± 10.1, P = .145) scores were demonstrated. There were no differences in readmissions (user = 5, nonuser = 4, P = .730) or reoperations (user = 5, nonuser = 2, P = .238).

Conclusion

Cannabis use does not appear to influence (adverse or beneficial) short-term outcomes in patients undergoing a primary TKA. Further studies are warranted to determine the efficacy and safety of cannabis as a constituent of multimodal pain management following TKA before endorsements can be made by orthopedic surgeons.

Section snippets

Methods

This study was approved by our institutional review board prior to initiation. The study period was from January 2014 to February 2018. The commercial sale of cannabis to the general public in the authors’ state was initiated on January 1, 2014. We utilized our institution’s longitudinally maintained TJA database to identify all patients who underwent unilateral primary TKA with a minimum 1-year follow-up duration. We retrospectively evaluated outpatient office charts for self-reported use of

Results

The mean age of the cannabis group was 61.0 ± 7.0 years, BMI was 27.1 ± 4.0, and the gender comparison was 48 males (67.6%) to 23 females (32.4%). This group was matched to a control group with age ±3 years, BMI ±3, and same gender. The mean length of stay was 46.9 ± 15.7 (users) vs 49.3 ± 20.4 (nonuser) hours (P = .464). In-hospital total morphine equivalents did not differ between the 2 groups (user = 137 ± 104 mg, nonuser = 146 ± 117 mg, P = .634). Postoperative ROM did not differ between

Discussion

Currently, there is little evidence to support the routine use of cannabis for medicinal purposes in patients undergoing elective TJA. Despite this, it appears that more patients undergoing TJA may be using, or reporting use for, both medicinal and/or recreational purposes since its legalization [7]. The primary aim of this study is to determine if cannabis use had clinical implications (ie, complications and outcomes) in patients undergoing primary unilateral TKA. Our results suggest that

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None of the authors have received funding for this research study and there were no individual funds received by any of the authors personally.

Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article.

Ethical Review Committee Statement: Our study involves human data and we have ethical board approval for our study.

Statement of the Location: Date collected for the use of this study was done at Colorado Joint Replacement.

One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to https://doi.org/10.1016/j.arth.2019.04.015.

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