Functional capacity and work ability in patients with chronic musculoskeletal pain

Abstract

Patients suffering from chronic low back pain (CLBP) and whiplash associated disorders (WAD) may experience many problems, including in work. Work ability is considered a balance between work demands and personal resources. Functional Capacity Evaluations (FCE) can be used to measure aspects of work ability. The main aim of this thesis was to obtain a better understanding of functional capacity and workability in patients with chronic musculoskeletal pain. Some FCEs claim to be able to detect submaximal capacity when maximal capacity is requested. This claim was studied in a systematic review. Three of seven studies were of good quality and demonstrated the ability to detect submaximal capacity. These tests used a lumbar motion monitor or visual observations accompanying a FCE lifting test. In a cross-sectional study the relationship between self-reported disability and functional capacity was investigated. The conclusion is that self-reported disability and functional capacity are related but different. Both constructs are complementary and both should be measured to comprehensively assess disability in patients with WAD. A small randomized controlled trial assessed whether adding a Short-Form FCE to a brief cognitive behavioral intervention could improve work ability. Eleven patients with chronic musculoskeletal pain were included. The intervention group improved 3.2 points on work ability (scale 0-10), while the control group improved 2.5 points. The improvements were clinically relevant in both groups. Feasibility was established. Clinical relevance of the addition of a Short-Form FCE is unconvincing. A cross-sectional study was used to determine how work ability is associated with pain, self-reported disability, quality of life and claim status in 438 patients with WAD and CLBP. Physical functioning and self-reported disability were both associated with both CLBP and WAD, but the amount of explained variance is different. Ten rehabilitation expert-professionals were interviewed to explore their opinions about injury compensation in patients with WAD. All expert-professionals acknowledged that injury compensation can influence rehabilitation, health and disability. The expert-professionals provided three causal pathways; a pathway through prolonged distress, a behavioral pathway, and patient characteristics that may either attenuate or worsen their response.