This study aimed to investigate the prevalence and characteristics of nociplastic pain in patients one year post-TKA using the revised IASP grading system.
A cross-sectional study was conducted on 47 patients (40 female; mean age: 71.8 ± 6.5 years) who had undergone TKA at the 1-year postoperative mark. Exclusion criteria included chronic pain resulting from implant loosening or prosthesis failure necessitating revision surgery, significant pathologies (unresolved fractures, tumors, acute trauma, or severe illness), and history of central nervous system disorders. Pain phenotypes were classified based on quantified assessments following IASP guidelines and a Delphi expert consensus. Nociceptive pain was identified through ultrasound-detected effusion, inflammatory markers, response to anti-inflammatory medications, movement-specific pain, and presence of myofascial pain syndrome. Neuropathic pain was determined using the Douleur Neuropathique 4 tool and clinical records. Nociplastic pain was characterized by widespread or regional pain, allodynia, hypersensitivity, and associated comorbidities. Pain intensity and disability were assessed using the Brief Pain Inventory (BPI), and comorbidities were assessed using the Central Sensitization Inventory (CSI). Quality of life was measured using the EQ-5D-5L questionnaire. The nociplastic and non-nociplastic pain groups were compared using statistical significance set at p 0.05.
One year post-TKA, 21 patients reported pain (BPI intensity: 2.0±1.7), while 18 patients were pain-free. Among those reporting pain, 67.9% specifically reported for nociceptive pain, 7.1% for neuropathic pain, and 7.1% for nociplastic pain. Additionally, 3.6% experienced mixed nociceptive and neuropathic pain, while 14.3% had mixed nociceptive and nociplastic pain. A subgroup of six patients (21.4%) exhibited characteristics of nociplastic pain, which was of significantly greater intensity, higher CSI scores, and lower EQ-5D-5L scores compared to the non-nociplastic pain group (n = 22; p 0.05).
This study revealed that 23.8% of patients experienced nociplastic pain one year post-TKA, with more severe symptoms observed in this subgroup.
By classifying nociplastic pain one year after TKA, clinicians could better identify patients who might benefit from a targeted multimodal treatment approach. This study has the potential to optimize outcomes through tailored physical therapy interventions to individual patients.
Total knee arthroplasty
Chronic post-surgical pain
