Preventing Iatrogenic Fibula Fractures Using the Push-Pull Technique: A Biomechanical Comparison of Unicortical Versus Bicortical Post Screws.

Background: Displaced diaphyseal fractures can be reduced using the push-pull technique, wherein a plate is affixed to the distal fragment of the fracture, a post screw is placed proximal to the plate, and a lamina spreader creates distraction. This study evaluated the load to failure and mechanism of failure of bicortical and unicortical post screws during reduction.

Materials And Methods: Four matched pairs of cadaver legs were subjected to a 2-cm oblique osteotomy simulating a displaced, oblique diaphyseal fracture.

Radiographic Anatomy of the Lateral Ankle Ligament Complex: A Cadaveric Study.

Background: When lateral ankle sprains progress into chronic lateral ankle instability (CLAI), restoring precise anatomic relationships of the lateral ankle ligament complex (LALC) surgically is complex. This study quantifies the radiographic relationships between the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and prominent osseous landmarks visible under fluoroscopy to assist in perioperative practices for minimally invasive surgery for CLAI.

Methods: Ten fresh frozen ankle specimens were dissected to expose the LALC and prepared by threading a radiopaque filament through the ligamentous footprints of the ATFL and CFL.

Characterization of regional variation of bone mineral density in the geriatric human cervical spine by quantitative computed tomography.

Background: Odontoid process fractures are among the most common in elderly cervical spines. Their treatment often requires fixation, which may include use of implants anteriorly or posteriorly. Bone density can significantly affect the outcomes of these procedures.

Relationship to drill bit diameter and residual fracture resistance of the distal tibia.

Background: The etiology of bone refractures after screw removal can be attributed to residual drill hole defects. This biomechanical study compared the torsional strength of bones containing various sized cortical drill defects in a tibia model.

Methods: Bicortical drill hole defects of 3 mm, 4 mm, and 5 mm diameters were tested in 26 composite tibias versus intact controls without a drill defect.

How Does Tibial Pin Placement in Navigated Total Knee Arthroplasty Affect the Torsional Strength of the Tibia?

Introduction: Surgical navigation technology has recently become more prevalent for total knee arthroplasty. Surgical navigation typically requires pin placement in the proximal tibia diaphysis to stabilize the bone-tracking hardware, and there have been several recent reports of fractures through these residual navigation pin holes. The objective of this biomechanical study was to determine whether a difference exists in the torsional bone strength of a 5-mm navigation pin hole drilled at a single location in three different orientations: unicortical, bicortical, and transcortical.

Quadruple Versus Double Flexible Intramedullary Nails to Treat Pediatric Distal-third Tibial Shaft Fractures: A Biomechanical Comparison.

Background: The vast majority of pediatric distal-third tibial shaft fractures can be treated with closed reduction and casting. If conservative measures fail, then these fractures are usually treated with 2 antegrade flexible intramedullary nails. A postoperative cast is usually applied because of the tenuous fixation of the 2 nails.

Cortical suture button fixation vs. bicortical screw fixation in the Latarjet procedure: a biomechanical comparison.

Background: The Latarjet procedure traditionally has been performed with 2 screws in an open manner. Recently, cortical suture button fixation for coracoid transfer has been used in hopes of mitigating complications seen with screw placement. The aim of this study was to evaluate a cortical suture button and technique currently available in the United States compared with screw fixation in the Latarjet procedure in a cadaveric model.

Biomechanical Evaluation of Humerus Fracture After Subpectoral Biceps Tenodesis With Interference Screw Versus Unicortical Button.

Purpose: To compare the torsional failure strength of the humerus after subpectoral biceps tenodesis with an interference screw versus a unicortical button in a human cadaveric model.

Methods: Thirteen matched pairs of fresh-frozen human cadaveric upper extremities were randomized to receive either 2.6 × 12 mm unicortical button or 6.

Biomechanical Evaluation of Dual Plate Configurations for Femoral Shaft Fracture Fixation.

Aim: This study aimed at comparing the mechanical properties of conventional and locking dual plates in adjacent and orthogonal orientations for the surgical fixation of transverse femoral shaft fractures. It also assessed the failure mechanics after dual adjacent and orthogonal locking plate removal.

Methods: Thirty-two composite femurs were transversally osteotomized and randomly assigned for fixation with either dual locking or compression plates in an adjacent or orthogonal configuration.

The Impact of Eccentric Diaphyseal Plate and Screw Placement on the Risk of Peri-Implant Fracture.

Background: The objective of this study was to determine the impact of the type and orientation of peripheral screw placement in an eccentrically positioned locking plate on the structural integrity of the plate-diaphyseal bone interface. We hypothesized that central placement of the screw at the end of the plate in this setting is more important than screw type (locking versus nonlocking) to limiting the risk of subsequent fracture.

Methods: Twenty osteoporotic fourth-generation composite left humeri were divided into 4 groups and plated with stainless-steel 6-hole locking plates and 4.

Effect of Plate in Close Proximity to Empty External-Fixation Pin Site on Long-Bone Torsional Strength.

Complex tibia fractures are often provisionally stabilized with external fixation prior to definitive fracture fixation. Bicortical defects, such as those left after removal of a fixator pin, can decrease the torsional strength of long bone. Evaluating the effect of subsequent plate fixation in close proximity to a defect on the torsional strength of the tibia is the purpose of this study.

The Effect of Suture Anchor Insertion Angle on Calcaneus Pullout Strength: Challenging the Deadman's Angle.

Background: Refractory cases of Achilles tendinopathy amenable to surgery may include reattachment of the tendon using suture anchors. However, there is paucity of information describing the optimal insertion angle to maximize the tendon footprint and anchor stability in the calcaneus. The purpose of this investigation is to compare the fixation strength of suture anchors inserted at 90° and 45° (the Deadman's angle) relative to the primary compressive trabeculae of the calcaneus.

Relationship Between Ulnar Variance, Cortical Bone Density, and Load to Failure in the Distal Radius at the Typical Site of Fracture Initiation.

Purpose: Increased ulnar variance has been shown to lead to diminished load borne by the distal radius. The purpose of this study was to determine the correlations among ulnar variance, bone mineral density, and load to failure at the distal radius.

Methods: Posteroanterior radiographs and computed tomographic scans were taken of 12 cadaveric forearms in neutral rotation.

Biomechanical Comparison of Bicortical, Unicortical, and Unicortical Far-Cortex-Abutting Screw Fixations in Plated Comminuted Midshaft Clavicle Fractures.

Purpose: The objective of this study was to assess the biomechanical properties of bicortical locking screws, unicortical locking screws, and unicortical far-cortex-abutting locking screw fixation in a cadaver model of comminuted midshaft clavicle fractures stabilized with a locking plate placed on the superior surface of the clavicle.

Methods: Nine pairs of adult fresh-frozen cadaver clavicles were allocated into 3 groups for either bicortical, unicortical, or unicortical far-cortex-abutting locking plate fixation. After a 1-cm osteotomy to simulate a comminuted fracture and instrumentation with an 8-hole locking plate placed on the superior surface of the clavicle, the specimens were mounted in a custom dual-gimbal fixture in a materials-testing system and tested in axial compression, torsional, and torsional load to failure.

Torsional Failure of Carbon Fiber Composite Plates Versus Stainless Steel Plates for Comminuted Distal Fibula Fractures.

Background: Carbon fiber composite implants are gaining popularity in orthopedics, but with few independent studies of their failure characteristics under supra-physiologic loads. The objective of this cadaveric study was to compare torsional failure properties of bridge plating a comminuted distal fibula fracture with carbon fiber polyetheretherketone (PEEK) composite and stainless steel one-third tubular plates.

Methods: Comminuted fractures were simulated in 12 matched pairs of fresh-frozen human fibulas with 2-mm osteotomies located 3 cm proximal to the tibiotalar joint.

Biomechanical evaluation of periprosthetic refractures following distal femur locking plate fixation.

Introduction: Distal femur fractures proximal to total knee femoral component constitutes the most prevalent type of periprosthetic fracture, and plate fixation treatment is associated with a 7.7% incidence of refracture proximal to the plate. The primary objective of this study was to compare proximal fixation techniques of a periprosthetic distal femur fracture plate in an osteoporotic bone model.

Ultrasound for Infants at Risk for Developmental Dysplasia of the Hip.

The best screening method for developmental dysplasia of the hip is controversial. Ultrasonography is sensitive, but cost-effectiveness may limit its use. This study assessed whether ultrasound screening would increase in effectiveness if targeted toward infants with established risk factors for developmental dysplasia of the hip and normal findings on physical examination.

Allograft Reconstruction of the Lisfranc Ligament.

Unlabelled: For Lisfranc injuries, screw fixation of the medial and middle columns is currently the standard of treatment. The purpose of this study was to biomechanically evaluate the use of allograft for a severed Lisfranc ligament compared to standard screw fixation and the intact condition. Six pairs of fresh-frozen cadaveric lower extremities were prepared with reflective marker arrays and cyclically loaded to simulate partial weight bearing under 4 sequential testing conditions: (1) intact ligament, (2) disrupted ligament, (3) tendon allograft reconstructed ligament, and (4) rigid screw fixation.

Accuracy of fluoroscopy versus computer-assisted navigation for the placement of anterior cervical pedicle screws.

Study Design: Randomized laboratory cadaver study.

Objective: The objective of this study was to determine the accuracy of anterior transpedicular screw placement in the cervical spine using conventional fluoroscopy versus computer-assisted navigation.

Summary Of Background Data: Traditionally, global cervical instability has required anterior and posterior fixation due to the superior biomechanical stability of circumferential constructs.

Gravity versus manual external rotation stress view in evaluating ankle stability: a prospective study.

Background: The purpose of this prospective study was to determine whether gravity versus manual external rotation stress testing effectively detects widening of the medial clear space in isolated ankle fractures when compared with the uninjured contralateral side.

Methods: Manual external rotation stress and gravity stress tests were performed on injured and uninjured ankles of ankle fracture patients in a clinic setting. Medial clear space measurements were recorded and differences between gravity and manual stress views were determined.

A biomechanical comparison of 2 hybrid techniques for elbow ulnar collateral ligament reconstruction.

Purpose: To compare the valgus laxity and fixation strength of 2 hybrid techniques for elbow ulnar collateral ligament reconstructions.

Methods: Reflective markers were placed near the ligament attachments of the ulnar collateral ligament on the humerus and ulna of 12 fresh-frozen cadaveric upper extremities for tracking displacement with 4 motion analysis cameras. Valgus laxity testing was performed on the intact, disrupted ligament, and reconstructed elbows by applying a 3.

Biomechanical comparison of bicortical locking versus unicortical far-cortex-abutting locking screw-plate fixation for comminuted radial shaft fractures.

Purpose: To provide comparative biomechanical evaluation of bicortical locking versus unicortical-abutting locking screw-plate fixation in a comminuted radius fracture model.

Methods: A validated synthetic substitute of the adult human radius with a 1.5-cm-long segmental mid-diaphyseal defect was used in the study to simulate a comminuted fracture.

Biomechanical comparison of first metatarsophalangeal joint arthrodeses using triple-threaded headless screws versus partially threaded lag screws.

Background: Triple-threaded, cannulated headless screws of varying thread diameters and pitch are designed to maintain thread length across the arthrodesis plane, provide joint compression, and reduce countersinking. This study tested the biomechanical fixation strength of conventional partially threaded lag screws compared to triple-threaded headless screws in first metatarsophalangeal joint arthrodesis.

Methods: First metatarsophalangeal joint arthrodesis using a crossed screw technique was performed on 11 paired, preserved cadaver first rays with two 4.

Biomechanical evaluation of a knotless barbed suture repair in a human Achilles tendon rupture model.

Background: Knotless barbed sutures are seeing more common use in wound closures and small tendon repairs. The purpose of this study was to evaluate the strength and resistance to gap formation of these sutures in larger tendons, such as the Achilles, compared with conventional repair.

Methods: Six matched pairs of fresh-frozen human cadaver Achilles tendons were transected to simulate a rupture.