Does Tramadol Have a Role in Managing the Pain of Knee OA?
Orthopaedic surgeons should use caution in prescribing tramadol to patients with knee osteoarthritis (OA): A study from NYU Langone Health has shown that total knee arthroplasty (TKA) patients who took tramadol preoperatively to treat knee OA had significantly less short-term improvement in functional outcomes than patients who were opioid-naïve.
Their findings were presented at the 2019 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS).
The researchers retrospectively reviewed prospectively collected data on 199 patients (120 females, 79 males) who underwent primary TKA at their institution between January 2017 and March 2018. They grouped patients into 3 categories:
- Opioid-naïve patients (n=136)
- Patients who took tramadol (n=21)
- Patients who took other opioids (n=42)
They then compared preoperative and postoperative KOOS Jr. scores among the groups. The average KOOS Jr. scores were similar in the 3 groups preoperatively but at 3 months postoperatively, patients in the tramadol group had less improvement than either of the other 2 groups. The difference in improvement between the opioid-naïve group and the tramadol group was statistically significant.
An AAOS clinical practice guideline published in 2013, Treatment of Osteoarthritis of the Knee – Evidence-Based Guidelines,  had strongly recommended using tramadol to manage patients with symptomatic knee OA. Since then, studies have shown that opioid-naïve TKA patients typically experience more improvement than those who had taken an opioid before surgery.
“While the negative consequences of postoperative opioid abuse are widely published in the medical literature, only recently [have studies] identified how opioids can result in worse outcomes if given before surgeries,” said lead study author Adam Driesman, MD, a resident physician at NYU Langone Health. “It has been shown that opioids are associated with cognitive dysfunction, respiratory depression, delayed wound healing, immunosuppression, impaired mobility, dependence and hyperalgesia, all of which can independently result in adverse health outcomes after surgery.”
The issue with most of these studies, though, is that they don’t include tramadol or group it in with other opioids, even though it is an opioid and carries the same risk of opioid-related adverse events.
“What was not known is how tramadol affects outcomes,” Dr. Driesman said. “Tramadol is a centrally acting synthetic opiate thought to induce its anesthetic effects through the mu opioid receptor. It is commonly used in the US, with a morphine equivalent dose of 0.1, and is perceived to have a low potential of abuse. As such, it is one of the most commonly prescribed opioids, with approximately 10% of all narcotic sales in the US.”
Given the assumed safety of tramadol, “We were surprised to find that [patients who take tramadol preoperatively had] worse outcomes as compared to other opioids,” Dr. Driesman said, noting that the study from NYU Langone Health is the first to demonstrate differences in outcomes with preoperative use of tramadol alone.
Although Dr. Driesman and his colleagues recommend that surgeons remain conservative in preoperatively prescribing any type of opioid, including tramadol, he emphasized that their study was retrospective in nature and, therefore, “all we could demonstrate is association, not causation. We believe prospective randomized trials are needed to properly identify how tramadol is associated with worse functional outcomes after TKA.
“While these results should be interpreted cautiously, clinicians should be cognizant of the potential negative side effects of tramadol. We believe that conflicting evidence presented in this study should be taken into account with the 2013 AAOS clinical practice guidelines.”
Dr. Driesman and his colleagues have transitioned opioids out of their pain management pathway for patients with symptomatic knee OA, instead using anti-inflammatory drugs, if tolerated by the patient, or acetaminophen if the patient has medical comorbidities that contraindicate the use of anti-inflammatory drugs.
Physical therapy also plays a role. “On top of a pharmaceutical regimen, we are still believers in physical therapy to improve mechanics,” Dr. Driesman said. “It has been proven in the literature to delay disease progression, possibly delaying future progression to an eventual TKA.”
Driesman A, Kaplan DJ, Feng J, Waren D, Vigdorchik JM, Meere PA, Fernandez-Madrid I, Slover JD, Macaulay WB. Tramadol in Knee Osteoarthritis: Should it Be a Strong Recommendation by AAOS? (Paper164). Presented at the 2019 Annual Meeting of the American Academy of Orthopaedic Surgeons, March 12-16, Las Vegas, Nevada.
- American Academy of Orthopaedic Surgeons. Treatment of Osteoarthritis of the Knee – Evidence-Based Guidelines, 2nd edition. 18 May 2013. Accessed May 2, 2019.