BACKGROUND The aim of this study was to examine the long-term effect of shortening after a midshaft clavicular fracture on strength deficiency in the shoulder. METHODS This study included 18 participants (14 males, 4 females) with a conservatively treated midshaft clavicular fracture. Mean age was 52.2 ± 13.8 years, range 32-76 years). The mean follow-up time was 13.5 ± 0.4 years. Participants filled in a QUICKDASH questionnaire and both clavicle lengths were measured using a caliper. The isometric strengths in internal rotation, external rotation and abduction of both arms were measured with a handheld dynamometer. RESULTS Average shortening of the clavicle in this group was 1.09 cm (SD 0.53). Nearly all strength measurements showed no significant difference between the shortened and the unaffected side. Multiple regression revealed a small (3N per mm length difference) but statistically significant relationship on external rotation between the relative extent of shortening of the clavicle, dominant side of the fracture and the isometric force difference between the unaffected and affected arm, F(2,15) = 5.746, p < .05, adj. R2 = .358. Over 14 years there was a reduction in mean DASH-score of 4.4 (8.8 ± 12.3; current DASH = 4.4 ± 7.7)In this group, long term effects of clavicular shortening were small. Based on these results we conclude that on the long term clavicular shortening will not result in significant strength loss.