Possible neuropathic pain prior to total knee arthroplasty (TKA) may be associated with persistent postoperative pain vs nociceptive pain in patients with osteoarthritis (OA), according to study findings published in the Journal of Pain Research. These links were found despite the fact that TKA is largely associated with a significant decrease in postoperative possible neuropathic pain, according to study findings published in the Journal of Pain Research.
The study included 158 consecutive patients with OA comprising 180 knees that underwent TKA. A numerical rating scale (NRS) was used to determine the preoperative and postoperative prevalence of neuropathic pain, nociceptive pain, and “unclear” pain in the knee. The investigators evaluated patients prior to operation and 6 months after the operation. Possible neuropathic pain comprised neuropathic pain and unclear pain. The researchers evaluated the association between possible neuropathic pain and pain intensity.
Preoperatively, neuropathic pain was found in 10 knees and unclear pain was found in 30 knees. Nociceptive pain was identified in the remaining 140 knees. The numbers of knees with neuropathic and unclear pain following TKA decreased 1 and 5, respectively, according to the NRS. Additionally, the prevalence of possible neuropathic pain reduced from 22.2% prior to surgery to 3.3% after surgery (P <.001).
The researchers observed a positive association between preoperative NRS and painDETECT questionnaire (PDQ) scores (r =0.385; P <.001). They also found a positive correlation between postoperative NRS and PDQ scores (r =0.365; P <.001).
In the 6 knees that had possible neuropathic pain after TKA, a total of 4 also had possible neuropathic after operation. The remaining 2 patients were classified as nociceptive pain prior to operation (P =.021). Knees that featured possible neuropathic pain following operation had significantly higher NRS scores after surgery compared with patients with nociceptive pain (P =.011).
The investigators noted that their study was limited by a lack of spinal disease assessments as well as the short follow-up period of 6 months.
These results suggest a link between preoperative neuropathic pain and the development of persistent postoperative pain after joint arthroplasty.
Hasegawa M, Tone S, Naito Y, Sudo A. Possible neuropathic pain in patients with osteoarthritis of the knee before and after total knee arthroplasty. J Pain Res. 2021;14:3011-3015.