Use of the 2006 Orlando criteria vs the 2007 Budapest criteria for the diagnosis of complex regional pain syndrome (CRPS) may lead to the misdiagnosis of patients experiencing unexplained excessive pain after total knee arthroplasty (TKA), according to a prospective study published in the Journal of Knee Surgery. This study found that >50% of these patients may be experiencing neuropathic pain.
A total of 100 consecutive patients who underwent TKA were prospectively evaluated 6 weeks after the procedure to determine whether the use of updated criteria for CRPS would result in a different diagnosis.
None of the patients enrolled in this prospective analysis exhibited signs or symptoms of CRPS in >2 of 4 subgroups. Excessive pain levels were recorded in 17 patients, 6 of whom reported isolated sensory symptoms. The most common signs were sudomotor and sensory in nature, and no motor/trophic changes were found in any of the patients.
Based on the Orlando criteria for CRPS diagnosis, a total of 8 patients would have been diagnosed with CRPS. Using the Budapest criteria, none of the patients in this cohort were diagnosed with CRPS. Of the 8 patients who had unexplained pain, 5 had a painDETECT questionnaire score indicative of neuropathic pain.
In this study, the small sample size and short follow-up period (6 weeks) preclude the ability to draw conclusive findings on the true incidence of CRPS after TKA.
The lack of CRPS diagnoses in this patient group using updated criteria “demonstrates the importance of using the Budapest criteria and considering alternative diagnoses including neuropathic pain.”
Kosy JD, Middleton SWF, Bradley BM, Stroud RM, Phillips JRA, Toms AD. Complex regional pain syndrome after total knee arthroplasty is rare and misdiagnosis potentially hazardous—prospective study of the new diagnostic criteria in 100 patients with no cases identified [published online January 2, 2018]. J Knee Surg. doi: 10.1055/s-0037-1615746