Smartphone app improves pain, reduces opioid use after knee replacement surgery

The use of the smartphone app (PainCoach) after surgery improved pain control and reduced opioid use in patients who underwent knee replacement, according to a recent study.

The research, presented at the 2019 Euroanaesthesia Congress in Vienna, found that more the study participants used the app, the more likely they were to decrease their use of opioids and lower pain scores.

Amar Sheombar from Kliniek ViaSana, in Mill, the Netherlands, and colleagues investigated the effect of the PainCoach app on pain and opioid use.

For the study, they randomly assigned 71 patients aged 56 to 70 years who were undergoing total knee arthroplasty into two groups: the app and usual care (38 patients) or usual care alone (33) for the first two weeks at home after surgery.

The app allowed patients to input their pain level (no pain, bearable pain, unbearable pain or untenable pain), and based on this information and the number of days after surgery, the app offered advice on drug pain relief use and exercises or rest. Questionnaires were used to establish opioid use (oxycodone) and pain levels at rest, during activity and at night, as well as other pain drug use, experiences with exercises, pain acceptance, function and quality of life. Participants completed questionnaires preoperatively, daily during the first two weeks, and after one month.

The amount of app use also was recorded, with active use defined as at least 12 uses of the app over two weeks. During the study, the average visual analog scale pain score was 23 (the scale is 0-100, where 100 represents the highest pain), and average opiate use across the group was less than half of one 5-mg oxycodone tablet per day.

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Key findings of the study include:

• Compared with the control group, users of the PainCoach app used 23% fewer opioids and 15% more paracetamol during the first 2 weeks after surgery.


• Regular use of the app led to a further reduction in opioid use and improved pain control during activity and at night.


• Regular app users (19 patients) reported four times faster reduction in pain during activity, six times faster reduction in pain at night, and 44% less opioid and 76% less gabapentin use compared with controls.


• Opioid use was substituted by 21% more paracetamol use in regular app users.

“These are important findings given the current demands on the health care system and the growing misuse of prescription painkillers worldwide,” said Sheombar. “Few clinically-tested mobile apps exist with clear measurable goals to guide patients in pain control and opiate use at home after surgery.”

“Knowing that 80% of interactive advice is remembered may explain why regular use of the PainCoach app contributes to lower pain scores and reduced opiate use,” Dr. Sheombar said. “Digital innovations like smartphone health care apps must empower patients and deliver patient-centric care. Three-quarters of the study patients found our app valuable and wanted to use it for real-time feedback and support. In the current study population, opiate use was already low. The app might have a much stronger effect in patient populations where preoperative opiate use is much higher.”