Arthro-kinematics of the elbow: study of the carrying angle

Abstract

The carrying angle of the elbow is usually assessed in full elbow extension, with a protractor goniometer, or derived from X-ray images. Substantial differences in carrying angle values have been reported, possibly explained by methodological differences. Carrying angles tend to show higher values in women than in men. The aim of this study was to confirm the previously described progressive decrease of the carrying angle as a function of increasing elbow flexion. After assessment of the carrying angle with a protractor goniometer and an electromagnetic tracking system (Flock of Birds) in extension, flexion-extension movements with the forearm held in supination were recorded by means of the latter system. Three recordings were averaged in both the left and the right elbows of 20 volunteers without a history of elbow pathology (10 males and 10 females; mean age 25 years). In extension, a mean (+/- SD) carrying angle of 11.6 +/- 3.2 degrees was found in the male and 16.7 +/- 2.6 degrees in the female subjects. The carrying angles progressively decreased with flexion, at the end changing into a mean (+/- SD) varus angle of 1.8 +/- 2.9 degrees in men and 1.6 +/- 2.3 degrees in women. Significant differences in carrying angles between the sexes were recorded in moving from 0 to 30 degrees of flexion (p < 0.03 for the left and p < 0.01 for the right elbows), but disappeared beyond 30 degrees . No statistically significant differences were found between the results of left and right elbows. Although statistically significant differences (p < 0.05 to p < 0.001) were found along the course of flexion and extension, these differences were small (<0.6 degrees ). The mean carrying angles at 0, 30, 60, 90 and 120 degrees of flexion revealed larger standard deviations in the male group than in the female group.

Motion‐derived coordinate systems reduce inter‐subject variability of elbow flexion kinematics

“…23,24 This can be explained by differences in coordinate system definitions. As our focus was on kinematics, our reference (humerus) coordinate system was aligned with the flexion axis.…”

“…Various studies have reported this to be between 118 and 208. 23,[25][26][27][28] In order to compare our valgus angulation to a carrying angle measurement, the humeral deviation angle is added, which ranges from 18 to 148. 29,30 With this correction, we find that our valgus angulation of 68 corresponds to a range of 7-208, which is in agreement with the range of reported carrying angles.…”

The carrying angle: racial differences and relevance to inter-epicondylar distance of the humerus

“…In general, it is agreed that CA increases with age because of skeletal growth and development [1,16,24]. In regard to gender, CA is usually greater in females than males; however, this tendency cannot be generalised because of large inter-individual differences [22]. Some earlier studies reported a greater value of the CA on the dominant arm in both Turkish and Greek populations [16,21,24].…”

“…The CA plays an important role in load carrying, where it helps avoid contact with lower limb bones and allows positioning of the hand directly above the centre of mass of the carried weight, thus producing a comfortable lever arm [22]. Unilateral changes in the angle may indicate previous trauma, developmental anomaly, or may relate to repetitive stress in athletes [7,13].…”

sEMG Techniques to Detect and Predict Localised Muscle Fatigue

“…The labelling by the fuzzy classifier was verified by a human expert using Table 3 as a guide. The changes in the elbow angle and their indication of fatigue is based on a study by Van Roy et al (2005). This study claims that changes in the elbow angle of 1.8 +/-2.9 degrees in men indicates fatigue.…”