Asymmetry of the ULNT1 elbow extension range-of-motion in a healthy population: Consequences for clinical practice and research

Objectives: To investigate the effect of isolated muscular variance, side and hand dominance on elbow-extension range-of-motion (EE-ROM) of the median nerve upper limb neurodynamic test (ULNT1). This study analyzes these variables potential to influence ULNT1 EE-ROM symmetry and the possible consequences for clinical practice and research. Study design: Controlled laboratory study, cross-sectional. Background: No normative data exist to interpret correctly EE-ROM. Clinical interpretation is based on bilateral comparison. This procedure assumes natural EE-ROM symmetry, with lack of scientific evidence. Methods: Nineteen participants with Langer's axillary arch (LAA), a muscular variant bridging the brachial plexus, were selected from 640 healthy volunteers, together with a matched control group. ULNT1 EE-ROM's were measured using the Vicon (R) optoelectronic system. Results: A full mixed model revealed no significant effects on EE-ROM for LAA and the variable side. Significant differences were found in EE-ROM between dominant and non-dominant sides (standard ULNT1 test position: 2.84 degrees +/- 1.60 degrees, p = 0.0004: ULNT1 with differentiating maneuver: 3.05 degrees +/- 1.98 degrees, p = 0.003). Approximately 30% of the subjects showed clinically detectable restriction (>= 10 degrees) of the dominant side EE-ROM. Conclusion: Hand dominance is significantly associated with restriction of EE-ROM, which results in a clinically detectable asymmetry. This compromises the clinical procedure of comparing the patient's EE-ROM to the opposite side. Erroneous conclusions could result in side to side analyses, if the effect is not taken into account in neurodynamic research. (C) 2011 Elsevier Ltd. All rights reserved.