Dorsal scapholunate interosseous ligament: ultrasound evaluation between dominant and non-dominant wrist in young sports patients

Purpose: The dorsal component of the scapholunate ligament, is the strongest component, in fact it has a maximum tensile strength of 300 N and mainly controls flexion and extension. In a recent study, the thickness and length of the dorsal component of SLIL was measured using ultrasound image, the length of the dorsal scapholunate ligament was 7.5 mm ± 1.4 mm and the thickness of 1.8 mm ± 0.4 mm. We evaluate 60 wrists of 30 young athletic volunteers with ultra-sound image, comparing the thickness variations of the dorsal component of SLIL between the dominant and non-dominant wrist, to confirm our hypothesis that the dorsal component SLIL has proprioceptive activity and therefore the thickness of the ligament increases in following wrist activity. Methods: With a high-frequency ultrasound probe > 15 MHz (Sonoscape X3 Pro) we evaluated 60 wrists of 30 young men (16 males and 14 females, 20–38 years old) manual sports volunteers (10 tennis players, 8 padel players, 7 swimmers, 5 weight lifters) with no recent ligament injuries of the hand or wrist to participate in the study, we compared the dorsal component of SLIL between the dominant and non-dominant wrist. Results: Dorsal SLIL was visualized in all 60 volunteers wrists. We measured an average scapholunate dorsal ligament length 7.7 mm and average thickness of 2.3 mm in the dominant wrist and average 7.2 mm in length and average 1.9 mm thickness in the non dominant wrist. The mean dorsal scapholunate interval was average 4.9 mm and the mean central interval was average 2.1 mm in the dominant wrist and 4.7 mm and 1.8 mm in the non dominant wrist, so that meas-urements remained unchanged with those reported by previous authors. Conclusions: In our study we ultrasonographically measured an average scapholunate dorsal ligament length 7.7 mm and average thickness of 2.3 mm in the dominant wrist and average 7.2 mm in length and average 1.9 mm thickness in the non dominant wrist. This confirms our hypothesis that there is a direct stimulus on the ligamentous component of the dor-sal SLIL in the dominant wrist following repeated uses and activities such as to cause an increase in thickness of the dorsal ligament to highlight the possibility of a proprioceptivity of the ligament if subjected to continuous training. Level of evidence: IV.