Prediction of outcome in women with carpal tunnel syndrome who receive manual physical therapy interventions: A validation study

Abstract

STUDY DESIGN: Secondary analysis of a randomized trial. BACKGROUND: A clinical prediction rule to identify patients with carpal tunnel syndrome (CTS) most likely to respond to manual physical therapy has been published but requires further testing to determine its validity. OBJECTIVE: To assess the validity of a clinical prediction rule proposed for the management of patients with CTS in a different group of patients with a variety of treating clinicians. METHODS: A preplanned secondary analysis of a randomized controlled trial investigating the efficacy of manual physical therapies, including desensitization maneuvers of the central nervous system, in 120 women suffering from CTS was performed. Patients were randomized to receive 3 sessions of manual physical therapy (n = 60) or surgical release/decompression of the carpal tunnel (n = 60). Self-perceived improvement with a global rating of change was recorded at 6- and 12-month follow-ups. Pain intensity (mean pain and worst pain on a 0-to-10 numeric pain-rating scale) and scores on the Boston Carpal Tunnel Questionnaire (functional status and symptom severity subscales) were assessed at baseline and at 1, 3, 6, and 12 months. A baseline assessment of status on the clinical prediction rule was performed (positive status on the clinical prediction rule was defined as meeting at least 2 of the following criteria: pressure pain threshold of less than 137 kPa over the affected C5-6 joint; heat pain threshold of less than 39.6°C over the affected carpal tunnel; and general health score [Medical Outcomes Study 36-Item Short-Form Health Survey] of greater than 66 points). Linear mixed models with repeated measures were used to examine the validity of the rule. RESULTS: Participants with a positive status on the rule who received manual physical therapy did not experience greater improvements compared to those with a negative status on the rule for mean pain (P =.65), worst pain (P =.86), function (P =.99), or symptom severity (P =.85). Further, the clinical prediction rule performed no better than chance in identifying the individuals with CTS most likely to respond to manual physical therapy or surgery (mean pain, P =.87; worst pain, P =.91; function, P =.60; severity, P =.66). No differences in self-perceived improvement were observed at either 6 (P =.68) or 12 (P =.36) months, according to the rule. CONCLUSION: The results of this study did not support the validity of the previously developed clinical prediction rule for manual physical therapy in women with CTS. LEVEL OF EVIDENCE: Prognosis, level 1b.