Premium
A mechanism‐based pain sensitivity index to characterize knee osteoarthritis patients with different disease stages and pain levels
Author(s) -
ArendtNielsen L.,
Egsgaard L.L.,
Petersen K.K.,
Eskehave T.N.,
Graven Nielsen T.,
Hoeck H.C.,
Simonsen O.
Publication year - 2015
Publication title -
european journal of pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.305
H-Index - 109
eISSN - 1532-2149
pISSN - 1090-3801
DOI - 10.1002/ejp.651
Subject(s) - summation , osteoarthritis , medicine , quantitative sensory testing , physical therapy , schmidt sting pain index , knee pain , anesthesia , sensory system , stimulation , psychology , pathology , alternative medicine , cognitive psychology
Background In a cohort of well‐characterized patients with different degrees of knee osteoarthritis ( OA ) and pain, the aims were to utilize mechanism‐based quantitative sensory testing ( QST ) to (1) characterize subgroups of patients; (2) analyse the associations between clinical characteristics and QST ; and (3) develop and apply a QST ‐based knee OA composite pain sensitivity index for patient classification. Methods Two hundred seventeen OA pain patients and 64 controls were included. K ellgren and L awrence ( KL ) grading scores were obtained, and pressure pain thresholds ( PPTs ), temporal summation of pain to repeated painful pressure stimulation and conditioning pain modulation ( CPM ) were assessed. Associations between pain score/area/duration, radiological findings and QST ‐related parameters were analysed. A pain sensitivity index was developed and applied based on PPT , temporal summation and CPM . z ‐Score, as statistical tool, was calculated for statistically comparing the pain index of a single patient with a healthy control group. Results High knee pain associated with low KL grade showed particular signs of pain sensitization. Patients showed significant associations between clinical knee pain intensity/duration and lowering of knee PPTs ( p < 0.01), facilitation of temporal summation ( p < 0.01), reduction of CPM function ( p < 0.01) and high pain sensitivity index ( p < 0.01). The index classified 27–38% of the OA patients and 3% of the controls as highly sensitive with no association to KL . The index increased for high knee pain intensities and long pain duration. Conclusions Radiological scores, contrary to clinical pain intensity/duration, were poorly associated with QST parameters. The pain sensitivity index could classify OA patients with different degrees of OA and pain.