Biomechanical Stability of Volar Plate Only Versus Addition of Dorsal Ulnar Pin Plate: A Dorsal Ulnar Fragment, C-3-Type, Distal Radius, Cadaver Fracture Model.

Objective: To determine if the addition of a dorsal ulnar pin plate provides improved stability characteristics in the management of intra-articular distal radius fractures with an associated dorsal ulnar fragment.

Methods: OTA/AO type C3 fractures, with a dorsal ulnar fragment of one-third or one-half the width of the distal radius, were simulated in 9 matched pairs of fresh-frozen cadaveric arms randomized between fixed-angle volar plate only versus volar plate with addition of a dorsal ulnar pin plate. Prepared specimens were mounted in a custom load frame and loaded in extension with stepwise cyclic load increase.

Effects of variations in Dwyer calcaneal osteotomy determined by three-dimensional printed patient-specific modeling.

Dwyer (lateral calcaneal closing wedge) osteotomy is commonly used in surgical correction of heel varus deformity. The purpose of this study was to determine the effect of wedge size and angle of osteotomy on deformity correction using preoperative imaging analysis with three-dimensional (3D) printed modeling. Seven patients diagnosed with pes cavovarus deformity who underwent Dwyer calcaneal osteotomy were identified retrospectively.

Effect of Metacarpal Fixation Configuration on Strength and Fracture Gap Displacements in a Cadaveric Model of Externally Fixed Distal Radius Fractures.

The purpose of the study was to determine the biomechanical effect of distal pin configuration in unilateral external fixation of distal radius fracture in a cadaveric model. A standardized 2-part extra-articular distal radius fracture model with dorsal comminution was created in 6 matched pairs of cadaveric upper extremities. Specimens within each matched pair were randomly assigned to either 4 or 6 cortices of distal pin metacarpal fixation.

Biomechanical Evaluation of Spring Ligament Augmentation With the FiberTape Device in a Cadaveric Flatfoot Model.

Background: The structural importance of the spring ligament complex in arch stability has been described. Furthermore, the pathology of this complex is often noted in patients with posterior tibial tendon dysfunction. The purpose of this biomechanical study was to evaluate spring ligament repair alone versus augmentation with the FiberTape device in a cadaveric flatfoot model.

Distal fibula osteotomies improve tibiotalar joint compression: A biomechanical study in a cadaveric model.

Background: Successful tibiotalar joint fusion relies on adequate compression. Compression following joint preparation may be affected by the extent to which the fibula holds the joint out to anatomical length. The purpose of this study was to evaluate the effect of various distal fibula osteotomies on tibiotalar joint compression.

Proximal Interphalangeal Arthrodesis of Lesser Toes Utilizing K-Wires Versus Expanding Implants: Comparative Biomechanical Cadaveric Study.

Background:: Lesser toe proximal interphalangeal (PIP) joint arthrodesis is one of the most common foot and ankle elective procedures often using K-wires for fixation. K-wire associated complications led to development of intramedullary fixation devices. We hypothesized that X Fuse (Stryker) and Smart Toe (Stryker) would provide stronger and stiffer fixation than K-wire fixation.

Three-Dimensional Morphometric Modeling Measurements of the Calcaneus in Adults with Stage IIB Posterior Tibial Tendon Dysfunction: A Pilot Study.

The pathophysiology of adult-acquired flatfoot deformity (AAFD) is not fully explained by degeneration of the posterior tibial tendon alone. While a shortened or dysplastic lateral column has been implicated in flatfoot deformity in pediatrics, there is no study that has quantified the degree of dysplasia in adults with a stage IIb flatfoot deformity, or if any exists at all. : An institutional radiology database was queried for patients with posterior tibial tendon dysfunction (PTTD) who had computed tomography (CT) performed.

Effect of Transosseous Tunnels on Patella Fracture Risk After Medial Patellofemoral Ligament Reconstruction: A Cadaveric Study.

Purpose: To determine whether (1) tunnels that breach the anterior cortex of the patella result in increased fracture risk and (2) transosseous tunnels drilled across the patella significantly reduce the tensile force needed to fracture the patella.

Methods: Twenty-six fresh-frozen cadaveric human patellas were randomized to 1 of 3 groups: a control group with unmodified patellas, a group with 2 transverse tunnels (TT) that did not breach the anterior cortex, and a group with 2 TT that breached the anterior cortex of the patella (PA). Patellas were connected in series to a load cell via freeze clamp attachments to the quadriceps and patellar tendons.

Effects of Medial Displacement Calcaneal Osteotomy and Calcaneal Z Osteotomy on Subtalar Joint Pressures: A Cadaveric Flatfoot Model.

Medial displacement calcaneal osteotomies have been shown to be successful in the surgical management of adult acquired flatfoot, in particular, stage 2 deformity. Classically, the medial displacement calcaneal osteotomy technique has been performed. However, a calcaneal Z osteotomy has been more recently described and applied in the surgical management of flatfoot deformity.

Effect of ulnar tunnel location on elbow stability in double-strand lateral collateral ligament reconstruction.

Background: Double-strand lateral ulnar collateral ligament (LUCL) reconstruction is an effective treatment for posterolateral rotatory instability (PLRI) of the elbow, but anatomic landmarks for ulnar tunnel placement are often difficult to identify intraoperatively, which potentially can result in a nonanatomic LUCL reconstruction. This study investigated the effect of ulnar tunnel location on joint stability in double-strand LUCL reconstruction.

Methods: PLRI was artificially created in 7 cadaveric elbows, and double-strand LUCL reconstruction was performed.

Time course of peri-implant bone regeneration around loaded and unloaded implants in a rat model.

The time-course of cancellous bone regeneration surrounding mechanically loaded implants affects implant fixation, and is relevant to determining optimal rehabilitation protocols following orthopaedic surgeries. We investigated the influence of controlled mechanical loading of titanium-coated polyether-ether ketone (PEEK) implants on osseointegration using time-lapsed, non-invasive, in vivo micro-computed tomography (micro-CT) scans. Implants were inserted into proximal tibial metaphyses of both limbs of eight female Sprague-Dawley rats.

Intraoperative fluoroscopic assessment of proper prosthetic radial head height.

Background: Selecting a properly sized radial head prosthesis is imperative during radial head replacement. Although there has been much emphasis on avoiding overlengthening of the radius, little has been studied about how to avoid shortening. The purpose of this study was to characterize how a radial head replacement appears on intraoperative fluoroscopy depending on the height of the prosthetic radial head.

The biomechanical cost of variable angle locking screws.

Introduction: Variable angle (VA) locking plates in fracture fixation surgery allow screws to be fastened to the plate within a conical "locus of vectors" in order to avoid existing prostheses, joint surfaces, or poor quality bone. Clinical failures of VA constructs in which screws have rotated at the plate/screw interface have been reported raising the concern that there may be a biomechanical cost for the increased flexibility that VA provides. The objective of this study was to test the mechanical properties of one commonly used VA locking mechanism with screws placed in both nominal and off-axis trajectories and compare these against the standard locking mechanism.

Biomechanical consequences of adding plantar fascia release to metatarsal osteotomies: Changes in forefoot plantar pressures.

Destruction of the normal metatarsal arch by a long metatarsal is often a cause for metatarsalgia. When surgery is warranted, distal oblique, or proximal dorsiflexion osteotomies of the long metatarsal bones are commonly used. The plantar fascia has anatomical connection to all metatarsal heads.

Comparison of Proximal and Distal Oblique Second Metatarsal Osteotomies with Varying Achilles Tendon Tension: Biomechanical Study in a Cadaver Model.

Background: The optimal surgery for reducing pressure under the second metatarsal head to treat metatarsalgia is unknown. We tested our hypothesis that a proximal oblique dorsiflexion osteotomy of the second metatarsal would decrease second-metatarsal plantar pressures in a cadaver model with varying Achilles tendon tension. We also tested the plantar pressure effects of two popular techniques of distal oblique osteotomy.

Biomechanical benefits of anterior offsetting of humeral head component in posteriorly unstable total shoulder arthroplasty: A cadaveric study.

Restoration of joint stability during total shoulder arthroplasty can be challenging in the face of severe glenoid retroversion. A novel technique of humeral head component anterior-offsetting has been proposed to address posterior instability. We evaluated the biomechanical benefits of this technique in cadaveric specimens.

Antibiotic-associated eosinophilic and occlusive arteritis in calves complicating preclinical studies of left ventricular assist devices.

Repeated bolus intravenous (IV) administration of large doses of beta-lactams and aminoglycosides has previously been associated with the development of eosinophilic and occlusive arterial lesions limited to the lungs in calves. Reviewing 13 years worth of records from left ventricular assist device implantation studies, morphologically identical segmental arterial lesions were present in 32 of the 56 calves receiving IV antibiotics, affecting lungs (6/50), kidneys (12/56), or lungs and kidneys (14/50). In 16 of these calves, renal arterial lesions spatially colocalized with renal cortical infarctions.