A subset of patients who undergo total knee arthroplasty (TKA) are on methadone maintenance. They require more and often unpredictable quantities of opioids to function as effective painkillers. This study aims to compare the opioid requirements and the immediate postoperative course for patients on methadone maintenance with those who are not, after a TKA.
A retrospective, case-control study was performed. From 2005 to 2010, 36 patients, who underwent a unilateral TKA, on chronic methadone maintenance were identified. A control group matched for age, gender, and body mass index comprised patients from the same period, who did not self-report taking methadone. Chart review and analysis of patient demographics, type of anesthesia used, preoperative methadone use, inpatient opioid use (converted to oral morphine equivalent doses), need for in-house pain management consult, length of hospital stay, and need for reoperation were performed.
Patients on chronic methadone maintenance used significantly more opioids than patients not on methadone during their entire inpatient stay (P < .001). This was demonstrated by a higher median daily usage of opioids and higher patient-controlled analgesia usage. Patients on methadone maintenance had a significantly longer postoperative inpatient hospitalization (P < .001). Finally, these patients required significantly more inpatient pain management referrals (P = .025).
There is a significantly higher opioid requirement, length of stay, and pain management consults in patients on methadone maintenance compared with those who are not after a TKA. These patients may benefit from a nonroutine approach to perioperative care in TKA.