Complex Regional Pain Syndrome (CRPS) physiotherapy management: a cohort, observational, prospective, longitudinal study across the South Island of New Zealand

Abstract

Physiotherapy management for CRPS is considered to be essential. However, there is a lack of validated evidence-based treatments. There is controversy between what treatment methods are safe or effective. Physiotherapy outcomes and interventions for patients with CRPS, referred to all outpatient clinics across the South Island of New Zealand, were evaluated. The aim of this project was to determine with an observational, longitudinal study the following: a) to measure patient outcomes and changes over time/natural history for one year after commencing physiotherapy; b) to document and categorise the standard physiotherapy interventional methods received; c) to identify predictors of patient outcomes; d) to investigate the efficacy of the current physiotherapy intervention for CRPS, and (d) to suggest a conceptual clinical model for the physiotherapy management of CRPS. Informed written consent from participants was obtained. Demographic data were collected as follows: the duration of time following injury to CRPS diagnosis and to the commencement of physiotherapy; age; gender; laterality affected; inciting injury; region; work status; ethnicity. Medical and psychological care were also documented. Pre and post outcome measures were measured at 6 weeks, 6 months and 1 year after commencing physiotherapy interventions by an independent telephonic interviewer. The following outcome measures were applied: (a) Pain intensity was measured using the Short form McGill Pain Questionnaire and an 11-point numerical rating scale; (b) functional ability was assessed using the 11-item Quick Disability of the Arm, Shoulder and Hand questionnaire (for those with CRPS of the upper limb), and the 23-item Foot Function Index for those with CRPS of the lower limb; (c) quality of life associated with disability was assessed using the 12-item World Health Organisation Disability Assessment Schedule 2.0 which was chosen as appropriate for both upper and lower extremities; (d) satisfaction of care was measured with the 9-item Deyo and Diehl Satisfaction Questionnaire. Potential predictors were administered once to indicate possible influences on the outcomes. These were the Health Anxiety Index, the Extraversion and Neuroticism scale of the brief-version Eysenck Personality Questionnaire, the Tampa scale for Kinesiophobia, and the 10-item psychological distress Kessler questionnaires. Seventy five participants signed consent to participate between December 2013 and 2018. Nine did not meet inclusion criteria. Fifty-two females and 14 males participated with ages ranging from 11 to 77 years (mean 46 years); New Zealand Europeans predominate as ethnic group; 57 (86%) had a CRPS Type 1 and 9 (14%) had a CRPS Type 2 diagnosis; fractures were the inciting event for 28 (42%) followed by soft tissue injury 24 (36%) and surgery 14 (21%), respectively. Statistical analysis used standard descriptive statistics: student-t tests to compare pre and post outcome measures; Mann Whitney U tests to determine baseline differences between the categorical or continuous predictor variables, and logistic regression analysis to determine predictive effects of continuous or categorical variables with a power of 0.8 and alpha of 0.05. Effect sizes with logistic regression were strictly determined with confidence intervals not equal to 1. Spearman correlation co-efficients were used with the suggested conceptual model. Results showed all participants had significant improvement; 24 (45%) participants made a complete recovery within one year following commencement of physiotherapy. No specific physiotherapy intervention significantly influenced recovery. Full recovery was correlated with the extraversion personality measure and the concurrent prescription of anticonvulsant analgesia. These findings suggest that the novel factor of personality extraversion warrants further investigation. A proposal was suggested towards a conceptual clinical model for the physiotherapy management of CRPS.