The characterisation of unexplained pain after knee replacement

Area of Science:

• Orthopedics
• Pain Medicine
• Rheumatology

Background:

• Chronic pain post-knee replacement (KR) is a significant issue.
• Many patients lack identifiable orthopaedic causes for persistent pain.
• Investigating pain sensitization, including neuropathic pain, is crucial.

Purpose of the Study:

• To characterize pain in patients with unexplained chronic pain after KR.
• To determine the prevalence of pain sensitization issues in this cohort.
• To explore the relationship between pain, psychosocial factors, and pain sensitization.

Main Methods:

• Prospective evaluation of 44 patients at a multidisciplinary clinic.
• Inclusion of patients pre-screened to exclude obvious surgical causes.
• Assessment by orthopaedic surgeon, pain specialist, rheumatologist, and physiotherapist.

Main Results:

• Pain sensitization identified in 25% of patients; 43% had nociceptive pain, 32% mixed.
• High average pain scores (6.7/10 VAS) significantly impacting daily life.
• 50% experienced depression, 25% widespread pain, associated with higher pain and sensitization rates.

Conclusions:

• Unexplained pain after KR frequently stems from pain sensitization, not local nociceptive issues.
• Screening for pain sensitization, widespread pain, and depression is vital.
• Multidisciplinary interventions are recommended for effective management.