Symmetry-preserving modeling for lithographic imaging.

In computational imaging and lithography, it has been a challenge for a numerical model to faithfully preserve symmetries in the physical imaging system. In this Letter, we present a project-to-symmetry-subspace (PTSS) method to prevent symmetry loss during the iterative generation of optical kernels. Essentially, PTSS is to project iterative vectors onto a predefined symmetric subspace when decomposing the transmission cross coefficient (TCC).

Private Equity: An Emerging Practice Model.

Private equity acquisitions are increasing among orthopedic practices. The concepts and vocabulary surrounding these deals may be foreign to physicians. There are both potential risks and potential benefits to physicians at the center of these complex deals, and a clear understanding of any proposed private equity acquisition is crucial.

Risk Factors for Skin Tears Following Collagenase Clostridium histolyticum to Treat Dupuytren Contractures.

Purpose: Skin tears are an unpleasant complication that may occur after collagenase Clostridium histolyticum (CCH) administration to treat Dupuytren contractures of the fingers. The purpose of this study was to determine risk factors for the development of this complication.

Methods: Over a 6-year period, patients with a measurable metacarpophalangeal or proximal interphalangeal joint Dupuytren contracture and a palpable cord treated with CCH were prospectively observed.

The Use of Contact Biomechanics to Study the Intact, Proximal Row Carpectomy and Scaphoid Excision, Four Bone Fusion Wrist.

The study of contact biomechanics of the wrist is a challenge. This is partly due to the relatively small size of the joint as well as the lack of space in the radiocarpal joint which makes the delivery of investigative materials such as pressure sensitive film without causing artifact, difficult. Fortunately, a number of authors have studied the intact wrist, the scapholunate ligament injured wrist, the proximal row carpectomy and the scaphoid excision, four bone fusion.

Optimization of Anterior Incision Placement for Distal Biceps Repair.

Introduction Damage to the posterior interosseous nerve (PIN) is a known complication when using a cortical button during distal biceps tendon repair. Prior studies show that the trajectory of the drill through the biceps tuberosity can affect the distance from the PIN. We develop a mathematical model to predict the location of the tuberosity based on a palpable bony landmark and patient demographic factors.

Total Wrist Arthrodesis: Indications and Clinical Outcomes.

Total wrist arthrodesis remains an important technique in the surgical armamentarium of upper extremity surgeons. The procedure has evolved over time but continues to provide reliable pain relief at the expense of wrist motion. It is indicated for management of a wide variety of upper extremity conditions, including rheumatoid arthritis, posttraumatic osteoarthritis, cerebral palsy, and brachial plexus injuries, and as a salvage technique after failed implant arthroplasty.

Superficialis Sling (Flexor Digitorum Superficialis Tenodesis) for Swan Neck Reconstruction.

Swan neck deformity, or hyperextension of the proximal interphalangeal joint, may occur secondary to trauma, rheumatoid arthritis, cerebral palsy, or Ehlers-Danlos syndrome, and can be treated with tenodesis of one slip of the flexor digitorum sublimis tendon. This technique has several variations, differing primarily in the specific location and method that a single slip of the flexor digitorum sublimis tendon is secured, but they all serve to create a static volar restraint against hyperextension. Options include tunneling the tendon through the bone of the proximal phalanx, attaching the tendon to the A1 or A2 pulley, or securing the tendon with bone anchors in the proximal phalanx.

Improving Value in Musculoskeletal Care Delivery: AOA Critical Issues.

Improving value in musculoskeletal health care has emerged as an important objective in both the United States and Canada. In order to achieve this objective, providers need to have a clear definition of value and an infrastructure for measuring outcomes of interest to patients and costs over the episode of care. Although national patient registries have been established in the United States and Canada, they nevertheless lag behind other registries worldwide in terms of collecting patient-reported outcomes and capturing data from a wide cross-section of hospitals and physicians.

Dorsal surgical approaches to the proximal interphalangeal joint: a comparative anatomic study.

Purpose: Adequate exposure of the articular surface of the head of the proximal phalanx is essential for reduction of intra-articular fractures of the proximal interphalangeal (PIP) joint. We compared the articular exposure obtained by a dorsal extensor-tendon splitting (Swanson), an extensor tendon-reflecting (Chamay), and an extensor mechanism-sparing approach.

Methods: The PIP joints of 24 digits from 6 fresh-frozen cadaveric specimens were randomly assigned to 1 of 3 dorsal surgical exposures: an extensor tendon-splitting, extensor tendon-reflecting, or extensor mechanism-sparing approach.

High-pressure injection injuries to the hand.

The severity of high-pressure injection injuries to the hand is often underappreciated on initial presentation. These injuries require urgent and thorough surgical débridement. Despite the advances in our understanding of this injury type and the decline in amputation rates, the risk of long-term morbidity with diminished function and chronic symptoms remains high, and the role of systemic steroids in treatment is uncertain.

Scaphoid excision and 4-bone arthrodesis versus proximal row carpectomy: a comparison of contact biomechanics.

Purpose: We compare scaphoid excision and 4-bone arthrodesis (FBA) with proximal row carpectomy (PRC) in terms of contact pressure, area, and location.

Methods: Six cadaveric forearms underwent simulated FBA with K-wires. We measured pressures in the radiocarpal joint with Fuji contact film after we applied a 200-N load via the wrist tendons with the wrist in neutral, flexion, and extension.

External fixation versus internal fixation for unstable distal radius fractures: a systematic review and meta-analysis of comparative clinical trials.

Objectives: There is no consensus on the surgical management of unstable distal radius fractures. In this systematic review and meta-analysis, we pool data from trials comparing external fixation and open reduction and internal fixation (ORIF) for this injury.

Data Sources: We searched electronic databases (including MEDLINE, EMBASE, and SCOPUS) and conference proceedings from 1950 to 2009 in the English literature.

Unstable distal radial fractures treated with external fixation, a radial column plate, or a volar plate. A prospective randomized trial.

Background: Optimal surgical management of unstable distal radial fractures is controversial, and evidence from rigorous comparative trials is rare. We compared the functional outcomes of treatment of unstable distal radial fractures with external fixation, a volar plate, or a radial column plate.

Methods: Forty-six patients with an injury to a single limb were randomized to be treated with augmented external fixation (twenty-two patients), a locked volar plate (twelve), or a locked radial column plate (twelve).