Does age and pain free grip strength predict outcome to MWM and exercise for tennis elbow?

Abstract

Purpose: The aim of this post hoc analysis of a recently conducted randomised control trial was to develop a preliminary clinical prediction rule (CPR) for identifying patients with tennis elbow (TE) likely to respond to physiotherapy mobilisation with movement and exercise (PT) early within rehabilitation. Relevance: Manual therapists do not have evidence-based means to identify patients who are likely to respond to PT a priori. Participants: 64 participants (21 female) with a mean age (SD) of 48.2 (7.4) years and on average (SD) duration of TE of 26.3 (28) weeks received standardised PT. Methods: Potential predictive factors and reference measures were recorded at baseline and three weeks. After three weeks, participants were categorised as having experienced 'success' or 'non-success' with treatment. Factors with univariate relationship (p<0.15) to 'success' were entered into a step-wise logistic regression model. Receiver operator characteristic curves were used to calculate cut-off points for continuous variables. Results: Age<49 years (+LR = 2.6), baseline affected side pain-free grip strength (PFGS)>112N (+LR = 2.3) and baseline unaffected side PFGS>336N (+LR = 2.1) were the final criterion of the CPR. Probability of success rose from 79% to 100% if all three CPR criteria were positive. Conclusions: For the first time, this post hoc analysis has created a Level IV CPR that identifies patients with TE that will respond to PT. Future studies are required to validate the rule and perform impact analysis.