How widespread should pain be to be defined as widespread?

Trajectories and Predictors of Weight-Bearing and Non-Weight-Bearing Pain in Knee Osteoarthritis: A 9-Year Follow-Up Study

Objective

To identify distinct developmental trajectories of weight-bearing pain (WBP) and non-weight-bearing pain (NWBP) and examine the trajectory predictors in individuals with or at risk of knee osteoarthritis.

Methods

We included 971 participants from the Osteoarthritis Initiative whose baseline magnetic resonance imaging data and 9-year follow-up data on pain were available. We applied group-based trajectory modeling to identify WBP and NWBP trajectories over 9 years. Univariate and multivariate multinomial logistic regression analyses were performed to examine the predictors of identified trajectories.

Results

Three distinct WBP trajectories were identified: "no pain" (32.4%), "mild pain" (44.6%), and "moderate pain" (23%). Three distinct NWBP trajectories were identified: "no pain" (50.9%), "mild pain" (33.4%), and "moderate pain" (15.7%). In multivariate analyses, high body mass index, depression, multisite pain, radiographic knee OA, and comorbidities were associated with worse development trajectories for WBP and NWBP. Weak quadriceps strength and bone marrow lesion were only associated with worse WBP trajectories, whereas low education level was only associated with worse NWBP trajectories.

Conclusion

The developmental course of pain is heterogeneous in WBP or NWBP. Quadriceps strength and bone marrow leisure may be WBP-specific predictors, whereas education level may be a NWBP-specific predictor. The assessment of knee pain should be more accurate, which may help select appropriate therapeutic targets.

Pain Widespreadedness, and Not Primary Pain Location, is Associated With Comorbid Symptoms in Children With Chronic Pain

OBJECTIVES

Pediatric chronic pain represents heterogeneous diagnoses; often, primary pain location informs research classifications and treatment. In contrast, recent research has highlighted the role of widespread pain and this perspective has been adopted in assessments in specialty pediatric pain clinics. The lack of direct comparison between these 2 methods of categorizing pediatric chronic pain may hinder the adoption of evidence-based practices across the spectrum of care. Therefore, this study aimed to compare whether primary pain location or pain widespreadedness is more informative for pain-related symptoms in pediatric chronic pain.

METHODS

Youth (n=223) between the ages of 8 to 23 years (M=15.93, SD=2.11, 83% female) completed surveys upon intake at the pediatric chronic pain clinic. Free-text entries of primary pain location were coded into categories: headache, abdominal pain, and musculoskeletal pain. Additional domains assessed included widespread pain, pain interference, kinesiophobia, catastrophizing, anxiety, depression, sleep, and fatigue.

RESULTS

Differences based on primary pain location only emerged for kinesiophobia, F(2150)=8.20, P<0.001, with the highest scores among those with musculoskeletal pain. In contrast, controlling for sex, age, and pain intensity, pain widespreadedness was associated with pain interference, pain catastrophizing, fatigue, anxiety, and depression (P<0.05).

DISCUSSION

Pain widespreadedness was more consistently associated with pain-related outcomes among pediatric chronic pain patients than primary pain location, and body maps may be useful in determining a nociplastic pain mechanism to inform treatment. Improved assessment of pediatric pain mechanisms may help advance more precise treatment delivery.