The latest freshwater giants: a new Peltocephalus (Pleurodira: Podocnemididae) turtle from the Late Pleistocene of the Brazilian Amazon.

Overkill of large mammals is recognized as a key driver of Pleistocene megafaunal extinctions in the Americas and Australia. While this phenomenon primarily affected mega-mammals, its impact on large Quaternary reptiles has been debated. Freshwater turtles, due to the scarcity of giant forms in the Quaternary record, have been largely neglected in such discussions. Here we present a new giant podocnemidid turtle, Peltocephalus maturin sp. nov., from the Late Pleistocene Rio Madeira Formation in the Brazilian Amazon, that challenges this assumption. Morphological and phylogenetic analyses of the holotype, a massive partial lower jaw, reveal close affinities to extant Amazonian species and suggest an omnivorous diet. Body size regressions indicate Pe. maturin possibly reached about 180 cm in carapace length and is among the largest freshwater turtles ever found. This finding presents the latest known occurrence of giant freshwater turtles, hinting at coexistence with early human inhabitants in the Amazon.

Viscoelastic properties of the human A2 finger pulley.

INTRODUCTION: Biomechanical evaluation of the viscoelastic properties tissue deformation, stiffness, and maximum breaking load of the human A2 pulley. We hypothesized that the A2 pulleys of index, middle, and ring fingers exhibit no difference regarding the aforementioned biomechanical parameters. METHODS: Forty-one A2 pulleys of 14 upper extremities (8 body donors) were assessed. Cyclic and load-to-failure testing were performed. The biomechanical parameters tissue deformation during cyclic and load-to-failure testing, stiffness, and maximum breaking load were determined. RESULTS: No significant differences between the fingers could be detected regarding the biomechanical parameters. A significant negative correlation could be detected between stiffness and deformation of the pulley. Significant positive correlations could be identified between stiffness and maximum breaking load and between maximum breaking load and deformation of the pulleys. CONCLUSIONS: Assessment of the viscoelastic properties of the A2 finger pulley promotes precise diagnosis of pulley lesions and will help to optimize treatment.

[Extensor tendon injuries of the thumb]. / Strecksehnenverletzungen des Daumens.

Extensor tendon injuries of the thumb include lesions of the tendons of the extensor pollicis longus, extensor pollicis brevis and abductor pollicis longus muscles. The latter is practically only affected in open injuries. Open injuries require a tendon reconstruction by suture followed by immobilization in the distal and an adequate aftercare depending on the zone of injury. In distal injuries static splinting is applied, whereas proximal injuries from T4 on require a dynamic after-treatment. Different courses of the tendon of the extensor pollicis brevis muscle exist distal to the metacarpophalangeal joint and must be considered. The rare ruptures of the extensor hood at the metacarpophalangeal joint provoke an ulnar displacement of the extensor pollicis longus or both extensor tendons with concomitant lack of active extension in the metacarpophalangeal and interphalangeal joints. This injury is often misdiagnosed as a rupture of the ulnar collateral ligament of the metacarpophalangeal joint. It should be treated by refixation of the ruptured structures. Closed chronic ruptures of the extensor pollicis longus tendon go along with a defect that requires a tendon transfer or a tendon autograft.

[Revision surgery for carpal and cubital tunnel syndrome]. / Revisionseingriffe beim Karpal- und Kubitaltunnelsyndrom.

BACKGROUND: Carpal tunnel syndrome, a compressive neuropathy of the median nerve at the wrist and cubital tunnel syndrome, a compressive neuropathy of the ulnar nerve at the elbow, are the two most common peripheral nerve compression syndromes. Chronic compressive neuropathy of peripheral nerves causes pain, paraesthesia and paresis. Treatment strategies include conservative options, but only surgical decompression can resolve the mechanical entrapment of the nerve with proven good clinical results. However, revision rates for persistent or recurrent carpal tunnel syndrome is estimated at around 5% and for refractory cubital tunnel syndrome at around 19%. Common causes for failure include incomplete release of the entrapment and postoperative perineural scarring. THERAPY: Precise diagnostic work-up is obligatory before revision surgery. The strategy of revision surgery is first complete decompression of the affected nerve and then providing a healthy, vascularized perineural environment to allow nerve gliding and nerve healing and to avoid recurrent scarring. Various surgical options may be considered in revision surgery, including neurolysis, nerve wrapping and nerve repair. In addition, flaps may provide a well vascularized nerve coverage in the case of recurrent carpal tunnel syndrome. In the case of recurrent cubital tunnel syndrome, anterior transposition of the ulnar nerve is mostly performed for this purpose. RESULTS: In general, revision surgery leads to improvement of symptoms, although the outcome of revision surgery is less favourable than after primary surgery and complete resolution of symptoms is unlikely.

[Revision surgery after failed (partial-) arthrodesis of the wrist]. / Revisionen nach fehlgeschlagenen (Teil­)Versteifungen am Handgelenk.

(Partial) arthrodeses of the wrist have been proven cornerstones to treat many lesions for decades, especially in the case of revision surgery. Four-corner, scapho-trapezo-trapezoidal (STT), radio-scapho-lunate (RSL) and total wrist fusions are very common techniques in hand surgery. However, even these proven surgical procedures have significant non-fusion rates. Prior to revising a failed arthrodesis, it is essential to analyse the latter failure precisely. A technically adequate revision is only feasible when based on a correct and meticulous analysis. The understanding of the biological processes and technical aspects of the implants are the basis for solving this issue.

[Anatomy of the trapeziometacarpal joint in the context of arthroplasty]. / Anatomie des Daumensattelgelenks unter Berücksichtigung der Endoprothetik.

The thumb has a crucial role in the hand due to its position with regard to the fingers. The CMC-1 joint enables an extraordinary range of motion, since its geometry allows for opposition. The former joint may often succumb to osteoarthritis because a great range of motion in combination with large forces, small contact areas, and thorough usage are always present. Joint replacement is challenged by the great range of motion based on the necessary joint stability and the demand for sufficient pain reduction. This review highlights the anatomy of the CMC-1 joint with regard to joint preplacement solutions.

[Metacarpophalangeal joint replacement]. / Der Gelenkersatz der Fingergrundgelenke.

BACKGROUND: Arthroplasty of metacarpophalangeal (MCP) joints is crucial for patients with rheumatoid arthritis. Motion preserving therapies are mandatory for this joint, since loss of function of the MCP joint is detrimental. Many protheses or spacers have been introduced over the last 80 years, but most of them have been dismissed due to major complications. CURRENT PROCEDURES: Since the 1960s the Swanson spacer has been established as the reference standard for motion preserving procedures of the finger MCP joints. High fracture rates of the spacer do not seem to limit function and patient satisfaction after all. Current long-term studies show at least promising results for pyrolytic carbon protheses with respect to range of motion, survival, and revision rates in comparison to the Swanson spacer.

[Scaphoid pseudarthrosis : Complex reconstruction using vascularized bone grafts]. / Skaphoidpseudarthrose : Komplexe Rekonstruktionen mithilfe vaskularisierter Knochentransplantate.

The most important goals of scaphoid reconstruction in pseudarthrosis are correction of the humpback deformity, the realignment of the proximal carpal row and the bony union of the scaphoid. Therefore, in most cases bone grafting is required. To increase the healing rate and to improve vascularization, several kinds of vascularized bone grafts have been developed. Pedicled grafts are preferably harvested from the dorsal or palmar side of the distal radius with fusion rates between 27% and 100%. Free microvascular grafts can be obtained from the iliac crest and the medial or lateral femoral condyle with fusion rates between 60% and 100%. For their application microsurgical equipment and skills are required. Up to now osteochondral grafts from the femoral condyle offer the only chance for joint surface replacement by transferring part of the surface of the femoropatellar joint. The use of vascularized grafts is still a matter of controversy, since their superiority is still unproven compared to nonvascularized grafts, which also achieved 100% fusion rates in several series. They are indicated in secondary procedures after failed reconstruction and nonunion with small avascular proximal pole fragments. Since no evidence-based guidelines exist, this article provides an experience-based treatment algorithm for scaphoid nonunion with special consideration to vascularized bone grafts.

[Anatomy and pathobiomechanics of the scaphoid]. / Anatomie und Pathobiomechanik des Skaphoids.

Among the carpal bones the scaphoid (Os scaphoideum) is the most important. The most frequent fracture of the carpus is a fracture of the scaphoid bone. The frequently occurring absence of healing of these fractures as well as unhealed ruptures of the ligament complex between the scaphoid and lunate, lead to the most severe biomechanical and thus the most severe clinical changes of the wrist. The detailed anatomy of the scaphoid, blood flow, ligament attachments, injury mechanisms and pathobiomechanics are described and illustrated.

Registration of phase-contrast images in propagation-based X-ray phase tomography.

X-ray phase tomography aims at reconstructing the 3D electron density distribution of an object. It offers enhanced sensitivity compared to attenuation-based X-ray absorption tomography. In propagation-based methods, phase contrast is achieved by letting the beam propagate after interaction with the object. The phase shift is then retrieved at each projection angle, and subsequently used in tomographic reconstruction to obtain the refractive index decrement distribution, which is proportional to the electron density. Accurate phase retrieval is achieved by combining images at different propagation distances. For reconstructions of good quality, the phase-contrast images recorded at different distances need to be accurately aligned. In this work, we characterise the artefacts related to misalignment of the phase-contrast images, and investigate the use of different registration algorithms for aligning in-line phase-contrast images. The characterisation of artefacts is done by a simulation study and comparison with experimental data. Loss in resolution due to vibrations is found to be comparable to attenuation-based computed tomography. Further, it is shown that registration of phase-contrast images is nontrivial due to the difference in contrast between the different images, and the often periodical artefacts present in the phase-contrast images if multilayer X-ray optics are used. To address this, we compared two registration algorithms for aligning phase-contrast images acquired by magnified X-ray nanotomography: one based on cross-correlation and one based on mutual information. We found that the mutual information-based registration algorithm was more robust than a correlation-based method.

The impact of different peripheral suture techniques on the biomechanical stability in flexor tendon repair.

PURPOSE: Flexor tendon repair consists of circumferential peripheral sutures in combination with core sutures to avoid fraying and reduces the exposure of suture material on tendon surface. The peripheral suture adds up to a tenfold increase of the biomechanical stability compared to the core suture alone. The purpose of our study was to determine the most favourable peripheral repair technique for tendon repair. METHODS: Seventy-two porcine flexor tendons underwent standardized tenotomy and repair using one of the following six methods (n = 12): simple-running (SR), simple-locking (SL), Halsted-mattress (HM), lin-locking (LL), Lembert-mattress (LM), and Silfverskiöld cross-stich (SCS) suture technique. The SL- suture was placed 2 mm; the HM, LM, SC, and LL suture were placed 5 mm from the tendon gap. The SR suture was placed 1, 2, and 3 mm from tendon ends; no additional core suture was applied. For cyclic testing (1000 cycles), elongation was calculated; for load to failure construct stiffness, yield load and maximum load were determined. RESULTS: The mean cyclic elongation for all tested suture techniques was less than 2 mm; there was no significant difference between the groups regarding elongation as well as yield load. The HM, LM, SCS, and LL suture techniques presented significantly higher maximum loads compared to the SR- and SL-sutures. The 3 mm SR showed significantly higher maximum loads compared to the 2 and 1 mm SR. CONCLUSIONS: Beside the distance from tendon gap, the type of linkage of the suture material across and beneath the epitendineum is important for biomechanical stability. Simple-running suture is easy to use, even with a slight increase of the distance from tendon gap significantly increases biomechanical strength. For future repairs of flexor tendon injuries, 3 mm stitch length is highly recommended for simple peripheral suture, while the Halsted-mattress suture unites the most important qualities: biomechanically strong, most part of suture material placed epitendinous, and not too complicated to perform.

[Anatomy and biomechanics of the distal radioulnar joint]. / Anatomie und Biomechanik des distalen Radioulnargelenks.

BACKGROUND: The functionality of the upper extremity is decisively based on rotation of the forearm. The rotation depends on the extent of motion of the distal radioulnar joint. Rotation enables complete and focused usability of the hand in order to cope with daily activities. The configuration of the distal radioulnar joint has developed over millions of years of evolution. ANATOMIC CONDITIONS: The triangular fibrocartilage complex is the crucial stabiliser of the latter joint since osseous structures are limited. The palmar and dorsal radioulnar ligaments belong to this complex. The superficial and deep parts of the latter ligaments insert both centrically in accordance to the axis of rotation and eccentrically. This arrangement guarantees stability of the joint throughout pronosupination. The interosseous membrane is a further relevant stabiliser that guarantees sufficient load transmission from radius to ulna. The distal oblique bundle of the interosseous membrane is outstanding in this context. The pronator quadratus muscle is the relevant dynamic stabiliser of the distal radioulnar joint. Contraction of the muscle prevents diastasis of the joint. The deep head of the muscle is always activated during pronosupination.

[Ligamentous lesions and instability of the finger joints]. / Ligamentäre Verletzungen und Bandinstabilitäten der Fingergelenke.

Joint capsule and ligamentous lesions are common injuries of the upper extremities. Athletes are particularly inclined to suffer from these injuries. Clinical and radiological examinations are the cornerstone of an adequate treatment. Ultrasound-based diagnostics as a non-invasive and dynamic investigation method are gaining increasing relevance based on the development of high resolution probes. A correct interpretation of the findings is only feasible with a comprehensive knowledge of the anatomy. The most important goal is stability as a prerequisite for early active and passive motion with unrestricted range of motion.

[Diagnosis and treatment of degenerative disc lesions of the wrist]. / Diagnostik und Therapie der degenerativen Diskusläsion.

BACKGROUND: The triangular fibrocartilage complex (TFCC) widens the radiocarpal joint and takes part in load transmission from the carpus to the forearm. It is thereby prone to degenerative changes. The painful situation that can accompany degeneration is called ulnar impaction. DIAGNOSIS: Clinical examination helps differentiate between various causes of ulnar-sided wrist pain. Standard X­rays are needed to determine ulnar variance and stress radiographs can depict narrowing of the ulnocarpal joint space under load. MRI may prove degeneration of the TFCC itself or may indirectly confirm ulnar impaction in the presence of bone marrow edema in the ulnar head or at the proximal ulnar aspect of the lunate. TREATMENT: If conservative treatment fails to alleviate symptoms, arthroscopy may be indicated. On the one hand, this completes the diagnostic cascade, and, on the other hand, allows decompression of the ulnocarpal joint space by resection of the TFCC with partial resection of the ulnar head (wafer resection). In the case of ongoing pain, ulnar shortening sufficiently alleviates ulnar-sided wrist pain. Thereby, modern standardized operation techniques are safe enough to ensure bone healing at the osteotomy site. The aim of alleviating ulnar-sided wrist pain is mostly achieved if the correct treatment option is chosen.

[Defect coverage of fingers and thumb : Indications and treatment]. / Defektdeckung an den Fingern und am Daumen : Indikation und Therapie.

Due to the exposure of the hands in the daily routine, defect wounds of the hand are common. The injury severity varies and ranges from small fingertip defects to large soft tissue lesions with exposed tendons, nerves and vessels. The complete extent of the soft tissue defect is often only recognizable after meticulous debridement. A considerable variety of techniques for defect coverage are available to the surgeon but the actual challenge is to select the most appropriate procedure which will result in the smallest possible residual defect. This review article presents the diagnostic approaches to soft tissue defects of the hand and current treatment options.

High-resolution MRI (3T-MRI) in diagnosis of wrist pain: is diagnostic arthroscopy still necessary?

INTRODUCTION: 3T MRI has become increasingly available for better imaging of interosseous ligaments, TFCC, and avascular necrosis compared with 1.5T MRI. This study assesses the sensitivity and specificity of 3T MRI compared with arthroscopy as the gold standard. PATIENTS AND METHODS: Eighteen patients were examined with 3T MRI using coronal T1-TSE; PD-FS; and coronal, sagittal, and axial contrast-enhanced T1-FFE-FS sequences. Two musculoskeletal radiologists evaluated the images independently. Patients underwent diagnostic arthroscopy. RESULTS: The classifications of the cartilage lesions showed good correlations with the arthroscopy findings (κ = 0.8-0.9). In contrast to the arthroscopy, cartilage of the distal carpal row was very good and could be evaluated in all patients on MRI. The sensitivity for the TFCC lesion was 83%, and the specificity was 42% (radiologist 1) and 63% (radiologist 2). For the ligament lesions, the sensitivity and specificity were 75 and 100%, respectively, with a high interobserver agreement (κ = 0.8-0.9). DISCUSSION: 3T MRI proved to be of good value in diagnosing cartilage lesions, especially in the distal carpal row, whereas wrist arthroscopy provided therapeutic options. When evaluating the surgical therapeutical options, 3T MRI is a good diagnostic tool for pre-operatively evaluating the cartilage of the distal carpal row.

Advanced phosphorus removal via coagulation, flocculation and microsieve filtration in tertiary treatment.

The applicability of microsieve technology together with coagulation and flocculation for advanced phosphorus removal was investigated. A pilot unit including a microsieve with 10 µm mesh size was operated continuously with secondary effluent from Ruhleben wastewater treatment plant in Berlin. By applying a pretreatment of 0.07-0.09 mmol/L (as metal) coagulant and 1.5-2 mg/L cationic polymer, total phosphorus values below 80 µg/L were achieved. Coagulation with polyaluminum chloride (PACl) produced a better effluent quality compared to FeCl3, as less suspended solids and less residual coagulant were found in the microsieve effluent. In addition, the transmittance of UV radiation through the water was improved by using PACl. The produced amount of backwash water was always below 3% (on average 1.6%). Under optimized mixing conditions, polymer doses of 0.6 mg/L were possible without losses in water quality and filtration performance. Microsieving with chemical pretreatment is a viable option for high quality effluent polishing.

[The fibrous skeleton of the hand : Changes with Dupuytren's contracture]. / Das fibröse Skelett der Hand : Veränderungen bei der Dupuytren-Kontraktur.

The exact knowledge of the anatomy of the fibrous skeleton of the hand is an absolute prerequisite for any treatment of Dupuytren's disease. The fibrous skeleton does not only include the palmar aponeurosis, but also numerous retinacula cutis, which are not found in current anatomy books. Here, eponyms facilitate the otherwise difficult and over-pronounced names of the fiber systems. Skoog, Legueu and Juvara, Gosset, Grapow, Grayson, Cleland, Thomine, and Barton are the most important. This systematic review of the fibers and strands is designed to help reduce iatrogenic complications.

[Cubital tunnel syndrome : Diagnostics and therapy]. / Kubitaltunnelsyndrom : Diagnostik und Therapie.

Cubital tunnel syndrome is the second most common nerve compression syndrome observed in the upper extremity. Mechanical irritation of the ulnar nerve is also found in the upper and the lower arm even though cubital tunnel syndrome is documented most of the time. Apart from clinical examination electrophysiological testing is the most important contributor to the therapy decision. Depending on the clinical manifestation conservative treatment with elbow splinting may be appropriate. In the event of persistent or advanced nerve irritation surgical decompression may be the sensible intervention. Open or endoscopically assisted in situ decompression is currently recommended as the primary intervention while anterior transposition of the ulnar nerve is recommended for revision surgery.