The following is a summary of “Prognostic value of preoperative mechanical hyperalgesia and neuropathic pain qualities for postoperative pain after total knee replacement,” published in the June 2024 issue of Pain by Vigotsky, et al.

Researchers conducted a retrospective study to identify preoperative factors associated with chronic pain after total knee replacement (TKR).

They examined the predictive value of quantitative sensory testing (QST) and PainDETECT for postoperative pain at 3, 6, and 12 months post-TKR. The preoperative and postoperative QST measures were assessed at 3 and 6 months in 77 patients with knee OA (KOA) and 41 healthy controls, along with neuropathic pain scores (PainDETECT). The QST parameters included pressure pain threshold (PPT), pain tolerance threshold (PTT), conditioned pain modulation (CPM), and temporal summation (TS) using cuff algometry, as well as mechanical hyperalgesia and TS to repeated pinprick stimulation.

The results showed that patients with KOA exhibited baseline hyperalgesia to pinprick stimulation at the medial knee undergoing TKR and cuff pressure at the calf compared to healthy controls. Lower cuff algometry PTT and mechanical pinprick hyperalgesia were linked to preoperative KOA pain intensity. Preoperative pinprick pain hyperalgesia accounted for 25% of the variance in pain intensity 12 months post-TKR. Preoperative neuropathic pain scores explained 30% and 20% of the variance in postoperative pain at 6 and 12 months, respectively. A reduction in mechanical pinprick hyperalgesia from before surgery to 3 months post-TKR was associated with lower postoperative pain at the 12-month follow-up.

Investigators concluded that increased sensitivity to pinpricks and nerve pain-like symptoms before surgery predicted chronic pain after total knee replacement.

Source: onlinelibrary.wiley.com/doi/full/10.1002/ejp.2295