Pain differences detected in patients with typical vs non-typical pain after TKR

Surgeons should alert patients with high preoperative depressive scores that they could have high self-reported pain postoperatively.

Issue: December 2016

Study results presented at the British Orthopaedic Association Annual Congress showed there were differences in perceived early postoperative pain of up to 15% between patients with non-typical pain compared with patients with normal pain who kept a pain diary after total knee replacement.

“The study shows different patients experience postoperative pain differently,” Catherine Gibson, MBCHB, MRCS, orthopaedic registrar at Great Western Hospital in Swindon, United Kingdom, told Orthopaedics Today Europe. “Most importantly, clinicians can identify those who are more likely to report higher pain levels of postoperative pain—those who score higher on preoperative depression scores — and they follow a similar recovery trend, although lagging behind, those who do not report depressive preoperative feelings,” she said.

Pain and depression scores used

At the preoperative assessment clinic, Gibson and colleagues presented a pain diary to 368 patients undergoing total knee replacement (TKR) who were to use it for 12 months. Of those patients, 85 patients completed the full assessment dataset. To identify abnormal patterns of pain perception and recognition, patients completed questionnaires for the Oxford Knee Score (OKS), the Hospital Anxiety and Depression Scale, and the Leeds Assessment of Neuropathic Symptoms and Signs. The patients also rated their pain with a 10-point VAS on postoperative days 1, 7 and 14. Researchers then identified 52 patients with typical pain and 33 patients with non-typical pain.

“We used a modified version of the Kellgren-Lawrence grading system for osteoarthritic changes on X-rays and tried to compare these to the symptoms that were reported from the patients,” Gibson said at the meeting.

Pain decline noted

When researchers compared the two groups, they found a significant difference in preoperative radiograph severity between the groups, which included mild radiographic changes in 15% of patients in the non-typical pain group and in 2% of patients in the typical pain group. Within the first 14 days after surgery, researchers noted significant differences in reported pain levels and the patients in the non-typical pain group reported worse pain. Postoperative OKS scores were distributed between the groups so higher pain scores were reported among the group with what was considered non-typical pain.

“Postoperatively, though, the first 2 weeks showed the most interesting results with similar decline in pain perception, but [a] persistently higher reported pain symptom profile in the non-typical pain patients,” Gibson said.

More data will help confirm results

Patients with high depressive scores should not be excluded for TKR as “they still show beneficial decrease in their perceived pain postoperatively,” according to Gibson. However, she said, clinicians and patients should be aware of the association of higher self-scored pain postoperatively with higher scores on depressive scales preoperatively.

According to Gibson, patients undergoing TKR at her center are still offered a pain diary as part of a pre-assessment program. Researchers hope this will increase patient numbers and improve the impact of this research.

“We also hope to extend our follow-up times, again adding to our impact. We hope to develop preoperative counselling to help those identified as [at] higher risk of postoperative pain and see if this helps to bring their postop scores back in line with those who do not exhibit preop depressive symptoms, hopefully reducing their length of stay in the hospital and saving money ultimately,” she said. – by Casey Tingle

Reference:
Gibson C, et al. Paper #316. Presented at: British Orthopaedic Association Annual Congress. Sept. 13-16, 2016; Belfast, Northern Ireland.

For more information:
Catherine Gibson, MBCHB, MRCS, can be reached at Great Western Hospital, Marlborough Rd., Swindon, SN3 6BB, United Kingdom; email: c.gibson@doctors.org.uk.

Disclosure: Gibson reports no relevant financial disclosures.