Abstract
Introduction
Opioids are an integral part of pain management following total joint replacement procedures; however, to date, no evidence-based guidelines which regulate opioid prescribing practices exist. In order to determine an appropriate number of opioids required to control pain for post-arthroplasty patients, it is important to understand why patients are using them. We sought to identify the causes of pain which necessitated opioid consumption for patients following total knee (TKA) and total hip (THA) arthroplasty.
Methods
The study cohort consisted of 55 patients (29 females, 26 males) who underwent either primary unilateral TKA (n=28) or THA (n=27). Prior to discharge, patients were provided with a pain diary in which to record details regarding the type of pain medication used, the time of use, pain score at the time of use, and the specific reason for use. Subjects returned the completed logs once they ceased opioid use post-operatively. Based on responses, we categorized reasons for use into either Activity, which was further classified into ADL and Exercise, or Rest, which was further classified into Sleeping, Sitting, and Laying Down. Average and frequency of opioid consumption was calculated for each category, along with the pain score at the time of use for each category. All dependent variables were compared between TKA and THA patients using separate independent samples t-tests or Chi-square tests.
Results
Overall, 13 patients did not consume any opioids during the post-operative period, and data regarding the specific reason for opioid use were available for 33 patients (16 THA, 17 TKA). For THA patients, the most common reason for opioid consumption was Sleeping (47%), followed by Exercise (20%), Sitting (16%), ADL (10%), and Laying Down (7%). Conversely, TKA patients reported the most frequent opioid use for pain during Exercise (32%), Sitting (28%), ADL (14%), Sleeping (14%), and Laying Down (12%). The frequency of consumption was greater for THA patients during Sleeping (p<0.001), but reduced during Exercise (P<0.001) and Sitting (p<0.001) compared to TKA patients. The average number of opioid pills consumed during ADL (p=0.05) and Exercise (p=0.02) was greater for TKA patients compared to THA. Pain scores reported during Exercise (p=0.33) and Sleeping (p=0.08) were similar between groups; however, TKA patients reported higher pain scores during Resting (p=0.047).
Conclusion
Our results demonstrate that the causes associated with opioid consumption following arthroplasty procedures differ between TKA and THA patients. Opioid use was most common at night during sleeping for THA patients, while TKA patients reported greater usage during the day while exercising or sitting. Our data can be used to counsel patients regarding pain expectations following TKA or THA and create standardized prescribing and tapering guidelines to effectively manage pain while limiting opioid use.
