Radio-luno-triquetral bone-ligament transfer as an additional stabilizer in scapholunate-instability

Introduction Reconstruction of the scapho-lunate (SL) ligament is still challenging. Many different techniques, such as capsulodesis, tendon graft and bone-ligament-bone graft have been described to stabilize reducible SL dissociation. If primary ligament repair alone is not possible, an additional stabilizer is needed to achieve scapho-lunate stability. A new local bone-ligament transfer using half of the radio-luno-triquetral ligament is performed. The direction of traction of the transposed ligament is very similar to the original ligament. Ideal tension can be attained by fixation of the bone block at the dorsal ridge of the scaphoid. The biomechanical stability of this bone-ligament transfer shall be examined biomechanically. Material and methods Computed tomography imaging was performed using eight cadaveric forearms with a defined position of the wrist. Axial load was accomplished with tension springs attached to the extensor and flexor tendons. Three series ([a] native, [b] divided SL ligament and [c]) after reconstruction with bone-ligament transfer] were reconstructed three-dimensionally to determine the angles between radius, scaphoid and lunate. The radial distal part including a bone fragment of the radio-luno-triquetral ligament was transferred from its insertion at the distal edge of the radius to be attached to the dorsal ridge of the scaphoid. Results SL gap was widened after its transection. Average SL distance was 6.6 ± 1.6 mm. After ligament reconstruction, the gap could be narrowed significantly to 4.2 mm (± 0.7 mm). The movement of the scaphoid and lunate showed significant changes, especially in wrist flexion, fist closure and radial deviation. These deviations could be corrected by the bone ligament transfer. Conclusion Reconstruction of a transected SL ligament with a bone-ligament transfer from the radio-luno-triquetral ligament reduces SL dissociation under axial load. The described surgical technique causes low donor-side morbidity and can be considered in addition to improve stability if SL ligament suture alone does not appear sufficient. Level of evidence Level II, therapeutic investigating experimental study.

Rupture of Extensor Pollicis Longus Tendon Caused by Scaphoid Nonunion Advanced Collapse Wrist

We report the case of a 69-year-old male patient with extensor pollicis longus (EPL) tendon rupture associated with a scaphoid nonunion advanced collapse (SNAC) wrist. He could not actively extend the left thumb interphalangeal joint and visited our institution for an examination. Plain X-rays revealed advanced stage SNAC and an enlarged soft tissue shadow owing to dorsal ridge growth. The patient was diagnosed with EPL tendon subcutaneous rupture due to SNAC. During surgery, the EPL tendon was found to be absent, a proximal-type scaphoid nonunion was detected, and bone growth to the dorsal part of the dorsal ridge was observed. Considering that the EPL tendon rupture was associated with the bone growth, we performed scaphoid lunate advanced collapse (SLAC) reconstruction and extensor indicis proprius tendon transfer which needed a revision tendon surgery afterward. To the best of our knowledge, EPL tendon ruptures caused by SLAC or SNAC are considered rare and have not yet been reported.

A new species of Megophrys (Amphibia: Anura: Megophryidae) from Vietnam

A new species of Megophrys is described from Cao Bang Province, northeastern Vietnam based on morphological and molecular data. Morphologically, the new species is distinguishable from its congeners by a combination of the following characters: Size small (SVL 34.9–38.9 mm in males); tympanum visible; vomerine teeth absent; tongue not notched posteriorly; male with a single vocal sac; toes with rudimentary webbing; subarticular tubercles and lateral fringes absent on all digits; nuptial pads present on fingers I and II in males, with spicules; dorsal skin with scattered granules and tubercles; flank with tubercles; dorsum with a X-shaped dorsal ridge; dorsolateral folds prominent; a small horn-like tubercle present at the outer edge of the eyelid; dorsal surface yellowish brown with a dark brown triangle between the eyes, and a dark brown marking along the X-shaped ridge on the back. In the phylogenetic analyses, the new species is unambiguously nested within the subgenus Panophrys with interspecific uncorrected genetic p-distances (16S rRNA gene) varying from 4.26% (compared with M. rubrimera) to 10.80% (compared with M. acuta).

A four-dimensional-CT study of in vivo scapholunate rotation axes: possible implications for scapholunate ligament reconstruction

Additional fixation of the palmar scapholunate interosseous ligament has been advocated to improve the long-term results of dorsal scapholunate interosseous ligament reconstruction. To investigate the validity of this approach, we determined normal scapholunate motion patterns and calculated the location of the scapholunate rotation axis. We hypothesized that the optimal location of the scapholunate interosseous ligament insertion could be determined from the scapholunate rotation axis. Four-dimensional computerized tomography was used to study the wrist motion in 21 healthy participants. During flexion–extension motions, the scaphoid rotates 38° (SD 0.6°) relative to the lunate; the rotation axis intersects the dorsal ridge of the proximal pole of the scaphoid and the dorsal ridge of the lunate. Minimal scapholunate motion is present during radioulnar deviation. Since the scapholunate rotation axis runs through the dorsal proximal pole of the scaphoid, this is probably the optimal location for attaching the scapholunate ligament during reconstructive surgery.

The larvae of Beraeamyia aphyrte Malicky 1972, Beraeamyia kutsaftikii Malicky 1975, and Beraeamyia matsakii Malicky 1980 (Trichoptera: Beraeidae), including a discriminatory matrix to the Greek Beraeidae larvae

This paper describes the previously unknown larvae of three Beraeidae species restricted to Greece: Beraeamyia aphyrte Malicky 1972, Bm. kutsaftikii Malicky 1975, and Bm. matsakii Malicky 1980 (Trichoptera: Beraeidae). Information on the morphology of the larvae is given, and the most important diagnostic features are illustrated. The trio of species can be easily separated by an angle present in the dorsal outline of the pronotal carina in Bm. kutsaftikii whereas this dorsal outline is straight in the remaining two species. Finally, the dorsal ridge of the pronotal carina touches the dorsal ecdysial line in Bm. matsakii, but fades far away from the ecdysial line in Bm. aphyrte. With respect to distribution, Bm. kutsaftikii is restricted to the mountains of Central Greece, the Peloponnesos, and the island of Euboea; Bm. matsakii is an endemic of the Ochi mountains in the southern part of Euboea and the island of Andros; and Bm. aphyrte is an endemic of the island of Crete. The species are integrated in a synoptic discriminatory matrix including the currently known Greek Beraeidae larvae. In addition, ecological information on the species is provided.

New findings about the intrascaphoid arterial system

We investigated the intraosseous arteries of six normal cadaveric scaphoids using red lead injection and three-dimensional reconstruction with micro-computed tomography. The arterial entrances were generally located around the dorsal ridge, the insertion of the scaphocapitate ligament and the radial part of the radioscaphocapitate ligament. Two to three trunk arteries entered the scaphoid on dorsal ridge at the level of the waist. The distal part of the scaphoid was mainly supplied by arteries from the waist. The blood supply of about 40% of proximal part of the scaphoid was poor. The blood supply from the scaphoid dorsal ridge plays an important role, not only for the proximal part of the scaphoid, but also for the waist and even the distal pole. The intrascaphoid arterial pattern may be contributory to nonunion, especially in proximal pole fractures.

The effect of screw trajectory for the reduction and association of the scaphoid and lunate (RASL) procedure: a biomechanical analysis

The purpose of this study was to determine if screw placement in the reduction and association of the scaphoid and the lunate (RASL) procedure affected the ability of the scapholunate joint to withstand force. After completely disrupting of the scapholunate ligament in 29 fresh-frozen cadaveric wrists, we placed the RASL screw either distal or proximal to the lateral aspect of the dorsal ridge of the scaphoid and into the dorsal or volar aspect of the lunate. Specimens were subjected to repeated cycles of transcarpal axial force, mimicking clenched-fist loading, until failure. Screw placement distal to the lateral aspect of the dorsal scaphoid ridge was significantly associated with failure when examined manually, radiographically (1.8 vs. 0.5 mm) and using real-time motion capture (diastasis: 1.6 vs. 0.4 mm; Euler angle: 4.5 ° vs. 0.8 °). The lateral aspect of the dorsal ridge is a reliable radiographic landmark on the scaphoid and provides surgeons with a convenient starting point to achieve the most biomechanically stable RASL construct, and, therefore, enhances the potential for an optimal clinical outcome.

The lower actinopterygian fauna from the Lower Carboniferous Albert shale formation of New Brunswick, Canada – a review of previously described taxa and a description of a new genus and species

The Lower Carboniferous Albert shale formation of New Brunswick, Canada, is well-known for the preservation of countless articulated lower actinopterygian palaeoniscoid fishes. This site is at the boundary between the Devonian and the Lower Carboniferous, making the lower actinopterygians preserved at this site important. The taxonomic history of previously described Albert shale formation actinopterygians is reviewed here. Many of the earliest described actinopterygian taxa from the Albert Formation are represented by poorly preserved type specimens and have the distinction of being moved from one paraphyletic genus to another paraphyletic genus. While these taxa are in need of major redescriptions, such work is premature until the large paraphyletic or polyphyletic genera they have been placed in, Palaeonicus[m], †Rhadinichthys, and †Elonichthys, are redescribed. But there is new diversity within the Albert shale formation. Here, a new lower actinopterygian species, †Lambeia pectinatus, is described from one well-preserved specimen. This new species is characterized by dorsal ridge scales with pectinated posterior margins, body scales inserted between adjacent dorsal ridge scales, body scales with pectinated posterior and ventral margins, the presence of a ventral rostro-premaxilla and a median rostral bone, a separate and distinct antorbital bone, and a single supraorbital bone. This newly described species is distinct from previously described fishes from the Albert Formation, and the morphology of this newly described species is more similar to later Carboniferous fishes rather than Devonian fishes. This suggests that morphological features commonly seen in Carboniferous fishes and rarely seen in Devonian fishes were present early in the Carboniferous.