Prevalence of Persistent Pain of the Neuropathic Subtype after Total Hip or Knee Arthroplasty

Purpose: This study aimed to (1) estimate the point prevalence of persistent postoperative pain (PPP) identified using the Self-Administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) after unilateral primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) using data from a registry of total joint arthroplasty (TJA) patients in Ontario, (2) estimate the effect of PPP on function, (3) estimate the prevalence of neuropathic pain (NP) features among patients with persistent pain, (4) determine participant characteristics in order to estimate the potential predictors of NP classification among individuals with persistent pain after TJA, (5) estimate the extent to which the estimates of prevalence depended on the measure used (i.e., S-LANSS vs. NP sub-scale of the Short-Form McGill Pain Questionnaire 2 [NP-SF-MPQ-2]), and (6) determine the difference in characteristics between those with and without NP. Method: This was a prospective follow-up study of a historical cohort of individuals who had undergone primary unilateral THA or TKA. Persistent pain was operationally defined as pain rated as 3 or more (out of 5) on the Oxford Pain Questionnaire 6 months or 1 year after THA or TKA. Participants with persistent pain completed the S-LANSS and the NP-SF-MPQ-2. Results: A total of 1,143 participants were identified as having had a TJA, 148 (13%) of whom had PPP. A total of 67 recipients completed the S-LANSS and the NP-SF-MPQ-2. Of these, an NP subtype was identified among 19 (28%; those with an S-LANSS score ≥ 12) to 29 (43%; those with an NP-SF-MPQ-2 score ≥ 0.91). Individuals with persistent pain of the NP subtype after TJA reported severe pain intensity and higher disability levels 1.5-3.5 years after surgery compared with those without persistent pain. Conclusions: A significant proportion of patients have persistent pain post-unilateral THA or TKA.