Roger A. Daley

Metacarpal fracture angulation decreases flexor mechanical efficiency in human hands.

&NA; The most common fracture of the hand occurs at the neck of the metacarpal. Despite clinical studies, controversy remains as to how much fracture angulation should be tolerated before more aggressive reduction is required. A controlled biomechanical model was used to simulate fifth metacarpal head fractures in fresh human cadaveric hands. Fracture angulation was varied from 0 to 90 degrees at 10‐degree intervals. We measured tendon excursion, tendon load, and work required to flex the small finger from full extension to full flexion with 10‐degree incremental increases in vertex‐dorsal angulation. Repeated measures analysis of variance revealed a significant decay in the efficiency of the flexor system when fracture angulation exceeded 30 degrees. Tendon excursion, load, and work requirements were all increased, confirming the detrimental effect of excessive fracture angulation on hand mechanics and function.

Free flap transplantation in mice

A new model is presented that adapts the standard experimental groin free flap model to the mouse. The femoral vessels upon which the microvascular anastomoses are based are very small (0.2–0.4 mm diameter in the artery), making this a technically challenging exercise. A 100% patency was achieved for flap replantation in ICR (outbred) mice. Success rates for flap transplantation in Balb/ C (syngeneic) mice rose from 20 to 75% with modification of the anastomoses from end‐to‐end to end‐to‐side procedures. This model offers new avenues of investigation when combined with recently developed transgenic mouse models.

Thrombodynamics of Microvascular Repairs: Effects of Antithrombotic Therapy on Platelets and Fibrin

PURPOSE To evaluate the hypothesis that platelets and fibrin differentially accrue at microvascular anastomoses in arteries versus veins and under different pharmacologic conditions. METHODS We evaluated mouse arterial and venous anastomoses with intravital fluorescence imaging, using fluorophore-labeled platelets and anti-fibrin antibodies to measure the extent of thrombus component development in the intraluminal anastomotic site. We evaluated systemic heparin or eptifibatide (platelet aggregation inhibitor) to determine their relative influences on thrombus composition. RESULTS Platelets accumulated rapidly in both arterial and venous repairs, and then fell in number after 10 to 30 minutes of reflow. Fibrin had a relatively steady development over 60 minutes in veins, with a more variable increase in arteries. Heparin reduced platelet accumulation in arteries and fibrin development in veins. Eptifibatide reduced platelets in both arteries and veins and had an apparent effect on lowering the amount of fibrin in veins. CONCLUSIONS These findings show that platelets have a rapid, transient response, whereas fibrin has a slower, more sustained accrual in both arterial and venous anastomoses. Furthermore, inhibition of either coagulation or platelet aggregation can influence presumably non-targeted components of thrombosis in vascular repairs of both arteries and veins. CLINICAL RELEVANCE Preventing replantation failure using antithrombotic therapies requires a better understanding of the effect of each pharmacologic compound on the various aspects of thrombogenesis.

Ultrasound Imaging Improves Identification of Prominent Hardware in the Surgical Treatment of Distal Radius Fractures: A Cadaveric and Prospective Clinical Study.

Background Volarly applied locking plates are one of several current treatment options for displaced fractures of the distal radius. Presently, surgeons use intraoperative depth gauges and fluoroscopy to select and confirm proper screw length. The contour of the dorsal cortex beneath the extensor compartments along with fracture comminution may limit the accuracy of screw length selection. Question/Purpose To evaluate the accuracy of ultrasound (US) and fluoroscopy in the detection of dorsally prominent screws placed during volar plating of experimentally created distal radius fractures and extend this prospectively into the clinical setting. Patients and Methods Distal radius fractures were experimentally induced in fresh cadaveric arms. The fractures were then internally fixated with volar locking plates utilizing fluoroscopic imaging. US imaging of the dorsal surface of the radius was then performed followed by dorsal dissection and direct caliper measurements to quantitate screw tips as recessed, flush, or protruding from the dorsal cortex. A small, prospective clinical study was also conducted to validate the clinical usefulness of using US to provide additional information regarding screw tip prominence. Results Our study demonstrated that US was able to detect dorsally prominent screw tips not visible on fluoroscopy. Cadaveric dissection showed a higher statistical correlation between US imaging and actual prominence than between fluoroscopy and actual prominence. Conclusions US examination after volar plate fixation of comminuted distal radius fractures may detect dorsal screw tip prominence when screw lengths are selected to engage the dorsal cortex. Level of Evidence IV.

Rat posterior facial vein interpositional graft: a more relevant training model.

Microvascular training models for vein grafting most often use the rat epigastric vein interpositioned to the femoral artery. We describe the rat posterior facial vein as an alternative vein graft model; it has at least a 2:1 diametric ratio to the femoral artery and a tougher connective tissue, making it more similar to clinical vein grafting for reconstructive microsurgery. A series of 24 grafts interpositioned to the femoral artery were done using 11–12 sutures per end‐to‐end anastomosis and yielded early patency rates of 96% at 20 min and 92% at 2 and 4 weeks for subsets of 12 grafts. As a training model the diametric disparity provides unique challenges with clinical relevance, for which a number of different techniques for matching arterial to venous circumferences can be done.

Pediatric blastomycotic osteomyelitis of the hand

Accurate and timely diagnosis of uncommon blastomycotic hand infections can pose a diagnostic challenge. The clinical manifestations can be extremely variable by mimicking many common diseases or aggressive tumors. Blastomycotic hand infections are typically associated with disseminated infections and the patient must be treated with a high index of suspicion for additional sites of involvement [2].

Orthotic Use in the Management of Epicondylitis: What is the Evidence?

Management of lateral epicondylitis remains a controversial topic. Use of immobilization for treatment and symptom control is not a new concept. Morris described the primary etiology and symptoms of “tennis elbow” in 1882. He also recognized the importance of immobilizing the arm. Splinting remains a key component of most treatment protocols. Literature on the efficacy of orthotic use alone is difficult to analyze because studies rarely investigate an isolated treatment modality but rather the efficacy of a comprehensive treatment program. With multiple treatment variables to consider, a precise determination of a particular modality is difficult. Therefore, current recommendations for splint use are predominantly based on traditional beliefs and anecdotal experience.