Chronic pain after primary total and medial unicompartmental knee arthroplasty for osteoarthritis: a Danish nationwide cross-sectional survey

BACKGROUND AND PURPOSE: Contemporary data on the risk of chronic pain after total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) is limited. Therefore, we aimed to investigate the incidence of chronic pain, pain characteristics, patterns of analgesic use, patient satisfaction, and willingness to undergo the same surgery again, 1 year after primary TKA and UKA for osteoarthritis.

METHODS: We conducted a nationwide online survey among unselected patients who underwent primary TKA or medial UKA for primary osteoarthritis in Denmark. At 1 year postoperatively, we assessed the incidence of moderate to severe pain (≥ 4 on the 0-10 numerical rating scale), frequency of pain, pain interference with everyday life, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain domain, the Douleur Neuropathique 4 interview (DN4i), use of analgesics, satisfaction, and willingness to undergo the same surgery again.

RESULTS: We sent survey invitations to 2,580 TKA patients and 1,007 UKA patients who underwent surgery in 2022. Of the 70% TKA respondents, 25% had moderate to severe chronic pain, 82% were satisfied/very satisfied with the result of surgery, and 86% indicated that they would choose to undergo surgery again. Of the 75% UKA respondents, 23% had moderate to severe chronic pain, 86% were satisfied/very satisfied, and 88% would undergo the same surgery again.

CONCLUSION: In Denmark, 25% of TKA patients and 23% of medial UKA patients experienced moderate to severe knee pain after 1 year. These numbers were higher than most previous estimates. Most patients were satisfied with the result of surgery and would undergo the same surgery again.