A study presented at the AAOS 2018 Annual Meeting reported that patients who undergo orthopaedic foot and ankle procedures are prescribed narcotic medication by nearly twice the amount that is actually consumed, leading to a significant surplus of narcotics available for potential diversion.

The study involved 1,009 patients undergoing outpatient procedures, primary investigator Joseph Daniel, DO, reported. Of the mean total of 43 pills (median, 40) prescribed, patients consumed a mean total of 22 pills (median, 20), translating to an overall utilization rate of 51 percent and to 21,196 pills left unused.

In general, excluding patients less than 18 years old, younger patients consumed more opioids than older patients, Dr. Daniel said. The median number of pills consumed by patients 18 to 59 years old ranged from 20 to 30, which was significantly more than the 11 to 13 (median) pills consumed by patients 60 to 79 years old (P < 0.012).

Significant differences in opioid consumption were seen based on the region of the foot and ankle operated on and whether surgery was performed electively or following trauma. For example, the median of 22 pills consumed by patients undergoing a hindfoot/ankle procedure was significantly greater than the median of 16 pills consumed by patients undergoing forefoot procedures (P = 0.002). Pill consumption for patients undergoing midfoot procedures was a median of 18 pills, which did not significantly differ from either of the other two locations (P > 0.237). Patients who underwent elective procedures consumed significantly fewer narcotic pain pills (median, 17 pills) than those who required surgery caused by trauma (median, 22 pills; P = 0.021). Conversely, no significant differences in opioid consumption were observed between patients undergoing soft-tissue procedures (median, 16 pills) and patients undergoing procedures involving manipulation of bony structures (median, 20 pills; P = 0.088).

Patients who underwent procedures that required regional anesthesia (popliteal block, popliteal and saphenous block) or a continuous infusion catheter required the most narcotic pain medication compared to patients receiving local or general anesthesia (P < 0.001). Furthermore, Dr. Daniel said, “The continuous infusion catheter group consumed significantly more (median, 27 pills) than those receiving a popliteal block (median, 20 pills; P = 0.008). The combined popliteal and saphenous block group consumed a median of 29 pills. Patients requiring only local anesthesia consumed the least amount (median, 7 pills).”

The researchers found that a higher preoperative visual analog score was a significant factor for increased opioid consumption (P < 0.001). Specifically, patients who scored ≥ 75 consumed a median of 30 pills whereas those who scored < 75 consumed only 18 pills. Patients with self-reported anxiety also were found to consume more narcotics than those without self-reported anxiety (P = 0.049). The median number of pills consumed by patients with anxiety was 24, while those without anxiety consumed 18 pills. Narcotic use did not differ based on smoking status (P = 0.710) or the presence of self-reported depression (P = 0.083).

‘Potential for abuse and diversion’

Dr. Daniel noted that although recent studies involving upper extremity procedure demonstrate overprescribing of opioid pain medication, “there remains a paucity of literature regarding utilization rates after lower extremity procedures.”

Without such information, foot and ankle surgeons may have “had no foundation for their prescribing habits besides their own personal experience,” Dr. Daniel said. “This often led to a gross discrepancy between the number of narcotic pills prescribed versus the number of narcotic pills that were actually consumed. As a result, there is a tremendous potential for abuse and diversion. We hoped that our study would provide surgeons with more insight on consumption patterns.”

Commenting on the results, Dr. Daniel said that the step-wise decrease observed in opioid consumption as age increased by decade may be explained by pain thresholds that increase with advancing age. Another consideration is the altered pharmacokinetics associated with normal physiologic aging, encompassing an increase in adipose tissue, a decrease in lean body mass, and a decrease in total body water. “As a result, lipophilic drugs tend to have a greater volume of distribution and take more time to be eliminated from the body. This generally causes drugs to be more potent and have a longer duration of action than predicted,” he said.

Regarding the finding that patients who received local anesthesia for their procedures were found to consume less opioids when compared to those who received general anesthesia, regional blockade, or continuous catheter analgesic infusion, Dr. Daniel said, “It is important to recognize that patients receiving local anesthesia were more likely to undergo procedures that required less soft-tissue or bony manipulation, which may inherently skew consumption patterns.”

He noted that the detection of no difference in narcotic utilization in patients who reported a history of depression or smoking versus those who did not is contrary to previous studies that show depression and nicotine abuse as risk factors for increased opioid consumption. Nevertheless, he said, “We continue to recommend that surgeons perform regular screenings for mental health disorders and counsel patients on tobacco cessation, as these comorbidities are important factors in limiting postoperative complications.”

Despite its prospective nature, a limitation of the study is the potential for inaccuracies in the pill-count data. Dr. Daniel said that 87 percent of patients had a pill count performed at the first postoperative visit to confirm the number of pills that were consumed, “and we relied on the patients to provide accurate information for the remaining 13 percent.” Additionally, he said, “We did not take into account adjuvants for pain relief such as NSAIDs, which may have skewed the amount of opioids that were consumed. We hope further studies include multimodal pain therapy and that consumption patterns are altered.”

He concluded, “Orthopaedic surgeons must take an active role in judiciously prescribing postoperative pain medication. Patients should be extensively counseled prior to surgery so they can set realistic expectations for pain control postoperatively. By standardizing postoperative prescription protocols, surgeons can better monitor their patients’ consumption patterns and recognize any aberrant behavior suspicious for diversion or abuse.”

Dr. Daniel’s coauthors of Scientific Paper 327, “A Prospective Evaluation of Opioid Consumption Following Orthopaedic Foot and Ankle Surgery,” are Sundeep Saini, DO; Elizabeth McDonald, BS; Kristen Nicholson, PhD; Ryan Rogero, BS; Megan Chapter, DO; Rachel Shakked, MD; Brian Winters, MD; and Steven Raikin, MD.

Terry Stanton is the senior science writer for AAOS Now. He can be reached at tstanton@aaos.org.