Clavicle Length and Hand Dominance – Does Asymmetry Exist and What are the Clinical Implications of this?

The assumption of symmetry regarding clavicular length has previously been found unreliable. With the decision to surgically fix clavicle fractures often being based on the degree of shortening, this assumption if untrue may change clinical practice. We hypothesized that asymmetry exists with clavicles on the dominant side being significantly shorter. Two individuals clinically measured 508 pairs of Asian clavicles. Length was defined as the distance between either the sternoclavicular joint (SCJ) and acromioclavicular joint (ACJ) or suprasternal notch (SSN) and ACJ. Both individuals measured these in both clavicles twice and in each volunteer twice to determine the extent or lack of symmetry and intra- and inter- observer reliability. Other parameters recorded included age, sex, race, occupation and hand dominance. Dominant clavicles were found to be significantly shorter by an average of 7mm and a maximum of 31mm. Intra- and inter-observer reliability were both excellent. Even if osteometric measurements are standardized using bony landmarks, we strongly advocate not applying this technique to clavicle measurements in view of the inaccuracy and unreliability, especially if this is going to determine the necessity for surgery in patients with fractures of the clavicle and what is thought to be shortening. Clavicle length is also likely related to hand dominance with clavicles of the dominant arm being shorter. Both these facts have significant implications on the clinical measurement of clavicular length post-fracture and its use as a determinant for surgery, something all orthopaedic surgeons should be made aware of.