Opioid Use Following Primary Unilateral Total Knee Arthroplasty Varies With Age.

BACKGROUND

Reducing unused prescribed opioids following arthroplasty procedures remains a challenge. The relationship between opioid consumption and age has seldom been investigated. We hypothesize that older patients consume fewer narcotic medications than younger patients following primary unilateral total knee arthroplasty (TKA).

METHODS

We retrospectively reviewed 506 primary unilateral TKA patients for perioperative opioid utilization. Patients were stratified by age at the time of operation (40-49, 50-59, 60-69, 70-79, 80+). Narcotic medications used in-house and in the 3 months following discharge were calculated and converted to morphine milligram equivalents (MMEs). Patients receiving an opioid prescription after 90 days postoperatively were classified as persistent opioid users (POUs). The duration of opioid use was calculated for non-POU patients as the time between surgery and their last opioid prescription. Differences in in-patient MME, outpatient MME, and POU were analyzed. The use of psychiatric medications, tetrahydrocannabinol (THC), and nicotine was also documented.

RESULTS

Younger patients were more likely to be chronic preoperative opioid users ( = .0074) and more likely to use antidepressants ( < .0001), nicotine ( = .0041), and THC ( < .0001). Younger age groups had the highest percentage of POU, which decreased with each subsequent decade ( = .0079). Younger patients also had an increased duration of opioid use ( < .0001) and total outpatient MME ( < .0001) within 3 months postoperatively.

CONCLUSIONS

Younger patients demonstrated higher postoperative opioid use following primary TKA; however, this was likely influenced by confounding factors such as preoperative opioid use, nicotine, THC, and antidepressant use. While age alone may not independently predict increased opioid consumption, these findings highlight the importance of identifying and managing modifiable risk factors to optimize pain control. Further research with larger cohorts is needed to better isolate the impact of age.