Study Investigates Prevalence of Neuropathic-Like Knee Pain

Individuals who suffer from knee pain (KP) also may suffer from neuropathic-like knee pain (NKP)—a result of localized damage to the nervous system and nerve fibers around a joint. Recent research aimed to determine the prevalence and risk factors of NKP, finding that NKP is driven by central risk factors and may require unique prevention and treatment strategies.

The researchers conducted a cross-sectional study using a postal questionnaire of responders in an East Midlands community in the United Kingdom. The questionnaire assessed KP severity, type (neuropathic versus nociceptive) using the modified painDETECT questionnaire, in addition to age, body mass index (BMI), significant knee injury, widespread pain, pain catastrophizing, and fatigue. Also, the researchers categorized risk factors into central and peripheral, and proportional risk contribution (PRC).

“KP can also be modified by central sensitisation following chronic nociceptor stimulation and alterations in central pain transmitting neurons and can result in NKP characteristics,” the authors wrote. “This could be induced by localised insult to the joint, by comorbid conditions or by psychological factors that modify pain physiology and descending pain modulation. However, such modifying factors are rarely studied and are often omitted in clinical assessments of KP.”

The results demonstrated that KP was reported in 28.2% of responders. Of those who reported KP, 13.65% had NKP, with women reporting more NKP. Additionally, after adjustments for age, gender, BMI, and pain severity, definite NKP showed associations with fibromyalgia, widespread pain, nodal osteoarthritis, injury, pain catastrophizing, and fatigue, when compared with non-NKP participants, according to the results. The researchers noted that although only central risk factors contributed to NKP, both central and peripheral factors contributed equally to non-NKP.

“Our study also demonstrated that diabetes associates with NKP compared with non-NKP, but not when compared with the non-KP group,” noted the study. “Although we did not differentiate type 1 and type 2 diabetes, it is plausible that the metabolic syndrome underlies the onset and progression of neuropathy and obesity, and its consequences are potential driving adverse factors that propagate altered nerve functioning and injury.”

The researchers concluded that the results emphasize the need for consideration of NKP characteristics and the balance of central and peripheral risk factors in those with KP in order to make treatment selections and improve patient care.

Reference

Fernandes GS, Valdes AM, Walsh DA, Zhang W, Doherty M. Neuropathic-like knee pain and associated risk factors: a cross-sectional study in a UK community sample. Arthritis Res Ther. 2018;20:215. doi: 10.1186/s13075-018-1717-6.