3D geometric morphometric analysis of the distal radius insertion sites of the palmar radiocarpal ligaments indicates a relationship between wrist anatomy and unique locomotor behavior in hylobatids.

OBJECTIVES: The objective of this study is to explore the anatomical differences in the insertion sites of the palmar radiocarpal ligaments between hylobatids and other hominoids that may be related to their different locomotor behaviors. MATERIALS AND METHODS: The morphology of the insertion sites of the palmar radiocarpal ligaments was analyzed with three-dimensional geometric morphometrics (3D GM) in the distal radial epiphysis of 44 hylobatids, 25 Pan, 31 Gorilla and 15 Pongo. RESULTS: Relative to other hominoids, hylobatid insertion sites of the palmar radiocarpal ligaments were relatively larger and the insertion site of the short radiolunate ligament had a palmar orientation. DISCUSSION: Larger palmar radiocarpal ligaments in hylobatids can help stabilize the wrist during the radial and ulnar displacement that occurs in ricochetal brachiation, the characteristic locomotor behavior of hylobatids, and compensate for the large traction loads on the wrist during extended-elbow vertical climbing.

Three-dimensional geometric morphometric analysis of the distal radius insertion sites of the palmar radiocarpal ligaments in hominoid primates.

OBJECTIVES: To identify anatomic differences in the insertion sites of the palmar radiocarpal ligaments in different species of hominoid primates that may be related to their different types of locomotion. MATERIALS AND METHODS: We have used three-dimensional geometric morphometrics (3D GM) to analyze the distal radius ligament insertion sites in 31 Homo sapiens, 25 Pan troglodytes, 31 Gorilla gorilla, and 15 Pongo pygmaeus. We have also dissected the radioscaphocapitate (RSC), long radiolunate (LRL) and short radiolunate (SRL) ligaments in six H. sapiens and five P. troglodytes to obtain quantitative values that were then compared with the results of the 3D GM analysis. RESULTS: H. sapiens had a relatively larger insertion site of the RSC + LRL ligament than the other hominoid primates. P. pygmaeus and P. troglodytes had a relatively large SRL ligament insertion site with a palmar orientation. In G. gorilla, the two ligament insertion sites were relatively smaller and the SRL insertion site had an ulnopalmar orientation. DISCUSSION: The morphological differences observed can be related to the types of locomotion used by the different species and to quantitative data obtained from the dissection of ligaments in H. sapiens and P. troglodytes. 3D GM analysis of ligament insertion sites can help in interpreting the types of locomotion used by extinct hominoid primates through the analysis of preserved fossilized fragments of the distal radius.

Reconstruction of Radioscaphocapitate Ligament in Treatment of Ulnar Translation.

Background This article measures the life quality, clinical, and functional outcomes of a patient who had undergone reconstruction of the radioscaphocapitate ligament (RSL), using brachioradialis tendon in the treatment of ulnar translation of the carpus. Case Description We present a 36-year-old man with ulnar translation in his left, nondominant wrist, after fall accident. Reconstruction of the RSL was performed. One year later, the patient experienced good evaluation. Wrist flexion was 70 degrees, extension was 60 degrees, radial deviation was 20 degrees, and ulnar deviation was 30 degrees. Forearm pronation was 85 degrees and supination was 90 degrees and digit motion was full. Disabilities of the Arm, Shoulder and Hand score of 5, Visual Analog Scale of 0, and grip strength of 82% were obtained compared with the unaffected side. Wrist radiographic aspects showed radiocarpal joint congruency. The period of fixator treatment was 8 weeks. Good stability and joint congruency of the radiocarpal joint were obtained. Good radiographic, clinical, and functional results were obtained improving the quality of life of the patient. Literature Review The treatment of ulnar translation is difficult and complicated. There is no consensus to the overall management. As there is still a lack of long-term results, the indications for surgery, various surgical options, and the type of intervention have been a matter of controversy in the literature. Would radiocarpal joint be stable when reconstruction of the RSL using brachioradialis tendon was obtained? Is it possible to reduce an ulnar translation with this technique? Clinical Relevance We would like to suggest that the radiocarpal ligament reconstruction will improve the outcome. We believe that this technique will make the wrist more stable and functional. We agree that the best time to perform the corrections is early. The authors prefer to first reconstruct the RSL and then the radiocarpal ligament suture or radioscapholunate arthrodesis.

Mechanical Properties of Palmar Radiocarpal Ligaments of Wrist and Their Clinical significances / 대한정형외과학회잡지

To study why the palmar capsular connections between radius and lunate remain intact in perilunate ligamentous injury of the wrist joint, and to compare the material properties of the short radiolunate, long radiolunate, and radioscaphoid region of the radioscaphocapitate ligaments (as the extrinsic ligaments) with those of the intrinsic ligaments of the previous papers, the anatomical and mechanical characteristics of those three palmar radiocarpal ligaments of twenty cadavers were measured and tested by a servo-hydraulic test machine. In spite of its small cross-sectional area (24% of short radiolunate ligament), the radioscaphoid ligament demonstrates a failure load of 58% and a stress of 260% of the short radiolunate ligament, and toughness similar to both the short and long radiolunate ligaments. This suggests that the radioscaphocapitate ligament may contribute as an initial constraint to perilunate injury. The failure load of the scapholunate ligament might be smaller than previously reported due to testing strain rate, which coupled with its short initial length may make it more vulnerable to injury at lower applied loads. The short radiolunate ligament, in spite of the largest width and cross-sectional area, has a failure load and toughness similar to the long radiolunate ligament. The material properties of short and long radiolunate ligaments may explain why the rest of the carpals persistently dislocate or fracture about lunate.