الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 151 |  |  |
| | | from | 151 | | |
Abstract
OA-related pain has a complex pathophysiology, including neuropathic peripheral and central abnormalities. Several clinical tools in the form of questionnaires making use of common verbal pain descriptors as (burning pain, electric shock, tingling and numbness) have been developed. They were used for assessment of neuropathic pain in OA patients. Five questionnares have been validated but only three of them (LANSS, DN4 and painDetect) are widely used.
The aim of the present study was to assess the frequency of neuropathic pain in patients with primary knee osteoarthritis, and to investigate its correlation with socio-demographic factors, physical function, quality of life, disease severity, and serum β-NGF level.
Seventy knee OA patients (47 females and 23 males) and twenty one age, sex and BMI matched healthy controls were included in the present study.
All patients were subjected to full history taking, clinical examination, plain X-rays for the knee joint. WOMAC, VAS, Lequesne index, OAKHQoL questionnaire and KL grading scale were used for assessment of functional status, pain, quality of life and disease severity in KOA patients. DN4 questionnaire and LANSS scale were used for assessment of neuropathic pain. Serum β-NGF levels were measured for patients and healthy controls.
In the present study, neuropathic pain was detected in 52.9 % of patients based on the DN4 questionnaire and in 38.6 % of patients based on the LANSS scale. KOA patients with neuropathic pain as detected by DN4 questionnaire have significantly higher WOMAC pain and WOMAC physical function and lower pain domain of OAKHQoL (P <0.0001, P= 0.015, P = - 0.005 respectively); whereas KOA patients with neuropathic pain as detected by LANSS scale have significantly higher Lequesne pain score and Lequesne index compared with patients without neuropathic pain (P=0.036, P=0.022 respectively).
DN4 score was positively correlated with WOMAC pain, WOMAC stiffness, and WOMAC physical function (rs=0.459, P<0.001, rs= 0.258, P= 0.031, rs= 0.307, P= 0.010, respectively) and negatively correlated with OAKHQOL pain score (rs= - 0.337, P= 0.004), while LANSS scale was positively correlated with WOMAC stiffness, Lequesne pain, and Lequesne index, (rs= 0.343, P= 0.004, rs= 0.344, P= 0.004, rs= 0.322, P= 0.007, respectively) and negatively correlated with OAKHQol physical, OAKHQoL mental health, OAKHQoL social support and total OAKHQoL scores (rs= - 0.258, P= 0.031, rs= - 0.254, P= 0.034, rs= - 0.283, P= 0.018, rs= - 0.261, P= 0.029 respectively).
Significantly higher serum β-NGF levels in KOA patients than controls (P<0.0001), and significantly higher serum β-NGF levels in KOA patients with neuropathic pain compared with patients without neuropathic pain were found (P= 0.01, P= 0.004 respectively). Serum β-NGF levels had positive correlations with neuropathic pain scores. Patients with higher serum β-NGF levels have longer disease duration, higher WOMAC pain, higher WOMAC physical function, higher total WOMAC, higher Lequesne pain, higher Lequesne daily activities of living, higher Lequesne index, lower pain domain of OAKHQOL, and lower social support domain of OAKHQOL.
According to linear regression analysis the higher scores of DN4 questionnaire were independently and significantly associated with higher WOMAC pain and WOMAC physical function scores; and higher serum β-NGF levels, while the higher scores of LANSS scale were significantly associated with longer disease duration, higher WOMAC stiffness score, higher Lequesne pain score, lower social support domain of OAKHQoL and total OAKHQoL score, and higher serum β-NGF levels.
In conclusion, in light of our findings, neuropathic pain is frequent in KOA patients. Quality of life and functional capacity are adversely affected and serum β-NGF level is higher in patients with KOA that have neuropathic pain. Longer disease duration, higher WOMAC, higher Lequesne pain, lower OAKHQoL and higher serum βNGF levels are significant predictors for higher neuropathic pain scores in KOA patients.
We recommend further longitudinal studies using further assessment tools for neuropathic pain associated with KOA pain; and further investigations to assess the role of β-NGF antagonists in relieving pain and improving functional status and quality of life in KOA patients.