Sensorimotor deficits in tennis elbow: results of a randomised controlled trial

Abstract

Purpose: The purpose of this randomised controlled trial was to evaluate the effect of three interventions: a physiotherapy programme, corticosteroid injections and wait and see on sensorimotor performance in patients with tennis elbow (TE). Relevance: TE is a common musculoskeletal condition affecting approximately 1% of the general population. The duration of TE can be up to 48 months even with treatment. The aetiology is not well understood, which is reflected by the multiple clinical treatments currently in use. Recent research suggests a neurophysiological component, evidenced by sensorimotor deficits such as upper limb reaction time and speed of movement in the order of 11-32% compared to healthy controls. However, changes in sensorimotor deficits in reponse to currently accepted treatments have not been assessed. Participants: 198 participants (mean age 47.6; SD 7.8) with a clinical diagnosis of unilateral TE were selected from the general community. Inclusion criteria included pain over the lateral humeral epicondyle which was aggravated by direct palpation, gripping and resisted wrist/finger extension. Exclusion criteria included bilateral symptoms or any other systemic, neck or upper limb pathologies. In addition, a healthy control group of 40 participants with no history of neck or upper limb pathology requiring treatment, were included in the baseline data collection. Methods: TE participants were randomised into one of three groups: the wait and see group were given advice; the corticosteroid injection group were given up to two injections and the physiotherapy group received eight treatments which consisted of “Mobilization with Movement” manipulation technique and a customised exercise program. Outcome measures of upper limb reaction time (simple, one- and two-choice), upper limb speed of movement, pain severity (visual analogue scale) and global improvement (5 point likert scale) were taken at baseline, then at 3, 6, 12, 26 and 52 weeks post-randomisation. Analysis: Continuous outcome measures were estimated using linear mixed models with participant defined as a random effect and treatment and time as fixed effects (p<0.01). Significant effects were further assessed using pairwise comparisons at the primary endpoints of six and 52 weeks (p<0.01). Univariate analyses of covariance were undertaken to examine the relationship between sensorimotor measures and patient characteristics (age, sex, duration of condition, previous elbow symptoms, additional treatment during follow up, recurrence of condition during follow up). Finally, comparison of both baseline and 52-week sensorimotor measures in the TE cohort with normative data were assessed using analysis of variance modeling (p<0.01). Results: Significant deficits in reaction time and speed of movement in the TE group compared to the control group were confirmed at baseline (p=0.003), with no difference between sides. Although sensorimotor measures significantly improved over time, there was no significant difference between treatment groups. Importantly, the TE group remained significantly worse at 52 weeks compared to the control group (p=0.008), despite the majority of participants reporting a successful outcome (159/190). Conclusions: It appears that the upper limb reaction time and speed of movement are affected bilaterally in unilateral TE and that these measures change over time, but this change is independent of treatment and not strongly related to baseline clinical characteristics. Implications: Sensorimotor deficits appear to be a part of the clinical and aetiological profile of TE, however current treatments do not preferentially affect these deficits. Treatments that specifically address sensorimotor deficits should be incorporated into the overall management of patients with TE. The clinical significance of sensorimotor deficits requires further investigation.

Keywords: Manual therapy, musculoskeletal, exercis