Latarjet procedure: biomechanical evaluation of 2-screw coracoid fixation.

Background: Coracoid nonunion is a relevant complication following the Latarjet procedure and is influenced by multiple factors, including the method of graft fixation. The purpose of this study was to evaluate and characterize the biomechanical properties of various two-screw fixation constructs used for coracoid graft fixation in the Latarjet procedure.

Methods: Forty model scapulae (Sawbones Inc.

Biomechanical Analysis of Pedicle Screw Fixation for Thoracolumbar Burst Fractures.

Treatment of unstable thoracolumbar burst fractures remains controversial. Long-segment pedicle screw constructs may be stiffer and impart greater forces on adjacent segments compared with short-segment constructs, which may affect clinical performance and long-term out come. The purpose of this study was to biomechanically evaluate long-segment posterior pedicle screw fixation (LSPF) vs short-segment posterior pedicle screw fixation (SSPF) for unstable burst fractures.

Biomechanical and Computed Tomography Analysis of Adjustable Femoral Cortical Fixation Devices for Anterior Cruciate Ligament Reconstruction in a Cadaveric Human Knee Model.

Purpose: To evaluate and compare two adjustable femoral cortical suspensory fixation devices used for anterior cruciate ligament reconstruction through a novel, direct computed tomography (CT) analysis metric and biomechanical laxity testing in a matched cadaveric human knee study.

Methods: Anterior cruciate ligament reconstructions with bovine tendon grafts were performed using two adjustable femoral cortical suspensory fixation devices (RigidLoop Adjustable [DePuy Synthes Mitek, Raynham, MA] and TightRope [Arthrex, Naples, FL]) in 12 knees (6 matched pairs). A mechanical testing series was used to determine each knee's laxity in the intact condition.

The effects of distal interlocking screws on torsional stability in three-part intertrochanteric hip fractures.

Objective: Many surgeons currently use long cephomedullary nails for the treatment of intertrochanteric fractures. The optimal indications for deploying distal interlocks are still debatable. This study examined the torsional biomechanical properties of 3-part intertrochanteric femur fractures in a cadaveric bone model using two different distal fixation strategies, an unlocked long cephalomedullary nail versus a dynamically locked nail.

Redefining the Economics of Geriatric Orthopedics.

Introduction: The heath care system in the United States is in the midst of a transition, in large part to help accommodate an older and more medically complex population. Central to the current evolution is the reassessment of value based on the cost utility of a particular procedure compared to alternatives. The existing contribution of geriatric orthopedics to the societal burden of disease is substantial, and literature focusing on the economic value of treating elderly populations with musculoskeletal injuries is growing.

Isolating Suture Slippage During Cadaveric Testing of Knotless Anchors.

We evaluated a testing method designed to isolate and analyze the effectiveness of different suture-retention mechanisms in knotless suture anchors used for rotator cuff repairs. Six knotless PushLock implants (Arthrex) with a suture-retention mechanism dependent on a press-fit of suture between the anchor's outer diameter and surrounding bone were compared with 6 ReelX STT devices (Stryker) reliant on an intrinsic suture-locking mechanism. Suture slippage beyond minimal clinical failure thresholds, as well as ultimate failure load, were determined with a novel testing fixture that isolated suture slippage.

Is distal locking of long nails for intertrochanteric fractures necessary? A clinical study.

Background: Few clinical studies have examined the utility of distal interlocking nails when fixing intertrochanteric fractures with intramedullary devices. In this study we performed a retrospective analysis comparing fixation method of intertrochanteric fractures with either a long unlocked cephalomedullary nail versus a long locked cephalomedullary nail. Our hypothesis was there would be no difference in device related failures or complications in stable intertrochanteric fractures treated with long locked or long unlocked cephalomedullary nails.

Long head biceps tenodesis with a knotless cinch suture anchor: a biomechanical analysis.

Purpose: The purpose of this study was to evaluate the initial fixation strength of 3 techniques of arthroscopic tenodesis of the long head of the biceps (LHB).

Methods: Eighteen human cadaveric shoulders were randomly assigned to one of 3 simulated arthroscopic biceps tenodesis techniques-simple suture (SS), Krakow stitch (KS), or lasso loop (LL)-combined with a knotless fixation implant (3.5-mm Piton Anchor; Tornier, Minneapolis, MN).

Cervical total disc replacement exhibits similar stiffness to intact cervical functional spinal units tested on a dynamic pendulum testing system.

Background Context: The pendulum testing system is capable of applying physiologic compressive loads without constraining the motion of functional spinal units (FSUs). The number of cycles to equilibrium observed under pendulum testing is a measure of the energy absorbed by the FSU.

Objective: To examine the dynamic bending stiffness and energy absorption of the cervical spine, with and without implanted cervical total disc replacement (TDR) under simulated physiologic motion.

Contribution of the medial malleolus to tibiotalar joint contact characteristics.

Background: Isolated medial malleolus fractures are typically treated operatively to minimize the potential for articular incongruity, instability, nonunion, and posttraumatic arthritis. The literature, however, has not clearly demonstrated inferior outcomes with conservative treatment of these injuries. This study measured the effects of medial malleolus fracture and its resultant instability on tibiotalar joint contact characteristics.

Biomechanical evaluation of the suture anchors used in open-door laminoplasty: a cadaveric study.

Study Design: A cadaveric study.

Objective: To determine whether the use of suture anchors is warranted in cervical laminoplasty.

Summary Of Background Data: The use of suture anchors to stabilize elevated laminae has been popularized in laminoplasty.

A biomechanical comparison of locked and unlocked long cephalomedullary nails in a stable intertrochanteric fracture model.

Objectives: This study compared the torsional properties of stable intertrochanteric femur fractures in a cadaveric bone model using 2 different distal fixation strategies: unlocked long cephalomedullary nailing versus dynamically locked nailing.

Methods: Fourteen matched pairs of cadaveric femora were randomly assigned to 1 of 2 distal fixation treatment groups: a single distal interlock screw placed in the dynamic orientation or no distal screw fixation. A stable 2-part intertrochanteric fracture was produced.

Is tip apex distance as important as we think? A biomechanical study examining optimal lag screw placement.

Background: Intertrochanteric hip fractures pose a significant challenge for the orthopaedic community as optimal surgical treatment continues to be debated. Currently, varus collapse with lag screw cutout is the most common mode of failure. Multiple factors contribute to cutout.

A biomechanical evaluation of locked plating for distal fibula fractures in an osteoporotic sawbone model.

Background: Supination external rotation (SER) injuries are commonly fixed with a one third tubular neutralization plate. This study investigated if a combination locked plate with additional fixation options was biomechanically superior in osteoporotic bone and comminuted fracture models.

Methods: Using an osteoporotic and a comminuted Sawbones model, SER injuries were fixed with a lag screw for simple oblique fibula fractures, and either a one third tubular neutralization plate or a locking plate.

Mechanical properties of revision ACL reconstruction.

The aim of this study is to evaluate the mechanical properties of a revision anterior cruciate ligament (ACL) reconstruction after redrilling the original tibial bone tunnel through a retained composite screw compared with initial soft tissue graft fixation. A total of 24 porcine tendons were fixed to porcine tibial tunnels with a 10 × 35 mm composite interference screw. Following the pullout test, a revision tunnel was drilled through the first interference screw and a second graft was fixed in the bone tunnel using a larger composite screw (11 × 35 mm).

Long-term clinical outcomes, motion, strength, and function after total claviculectomy.

Background: Total excision of the clavicle is rarely performed. No previous study has documented long-term outcomes with objective measurements of strength, motion, and patient-centered outcomes. We present the long-term consequences of total claviculectomy on shoulder girdle function, global upper extremity function, and overall general health.

Effectiveness of low-profile supplemental fixation in anterior cruciate ligament reconstructions with decreased bone mineral density.

Purpose: The purpose of this study was to compare anterior cruciate ligament (ACL) fixation using a bioabsorbable interference screw (BIS) and a supplemental low-profile suture anchor (PushLock 4.5-mm polyetheretherketone anchor; Arthrex, Naples, FL) with a standard BIS fixation to determine if fixation methods were dependent on tibial bone mineral density (BMD).

Methods: Ten matched pairs of fresh-frozen human female knee specimens (20 total) were harvested with specimen ages ranging from 40 to 65 years.

Effect of distal interlock fixation in stable intertrochanteric fractures.

The objective of this study was to evaluate the torsion stiffness of locked and unlocked distal fixation of long cephalomedullary nail constructs, in both a fresh fracture and healed, stable intertrochanteric fracture model. Samples were tested in both internal and external rotation (0±3 Nm) for a duration of 10 cycles. Each femur was tested without instrumentation (intact femur), with instrumentation and no fracture (healed intertrochanteric fracture), and with instrumentation with an osteotomy creating a stable intertrochanteric fracture (fresh fracture).

Wound hematoma after anterior cervical spine surgery: in vitro study of the pathophysiology of airway obstruction.

Airway obstruction by wound hematoma is a serious adverse event associated with anterior cervical spine surgery. Although intrinsic airway edema is the most plausible pathophysiologic mechanism of obstruction, we hypothesized that extrinsic compression of the trachea by a hematoma can result in airway occlusion at an angle to the sagittal plane. A silicone indenter and a servohydraulic test frame were used to apply pressure to the ventral neck of 7 human cadaveric specimens.

Effect of insertion of a single interference screw on the mechanical properties of porcine anterior cruciate ligament reconstruction grafts.

The objective of this study was to evaluate the mechanical properties of soft-tissue grafts following a single interference screw insertion of 4 different commercially available bioabsorbable interference screws. Twenty-four bovine proximal tibiae (12 matched pairs) were prepared and sagittally split to make 48 bone samples for testing. Tibiae were prepared for a 9 mm porcine tendon graft and were instrumented with 1 of 4 commercially available 10 x 35 mm composite screws, each with a different thread design.

Proximity of arthroscopic ankle stabilization procedures to surrounding structures: an anatomic study.

Purpose: To examine the anatomy of the lateral ankle after arthroscopic repair of the lateral ligament complex (anterior talofibular ligament [ATFL] and calcaneofibular ligament [CFL]) with regard to structures at risk.

Methods: Ten lower extremity cadaveric specimens were obtained and were screened for gross anatomic defects and pre-existing ankle laxity. The ATFL and CFL were sectioned from the fibula by an open technique.

Dynamic biomechanical examination of the lumbar spine with implanted total spinal segment replacement (TSSR) utilizing a pendulum testing system.

Background: Biomechanical investigations of spinal motion preserving implants help in the understanding of their in vivo behavior. In this study, we hypothesized that the lumbar spine with implanted total spinal segment replacement (TSSR) would exhibit decreased dynamic stiffness and more rapid energy absorption compared to native functional spinal units under simulated physiologic motion when tested with the pendulum system.

Methods: Five unembalmed, frozen human lumbar functional spinal units were tested on the pendulum system with axial compressive loads of 181 N, 282 N, 385 N, and 488 N before and after Flexuspine total spinal segment replacement implantation.

Biomechanical evaluation of mini-fragment hardware for supination external rotation fractures of the distal fibula.

Background: Supination external rotation distal fibula fractures are common, requiring fixation when associated with talar displacement. Subcutaneous distal fibula hardware may become painful, necessitating operative removal. We hypothesize that mini-fragment and small-fragment constructs will demonstrate similar biomechanical stability.

Effect of interference screw fixation on ACL graft tensile strength.

Tibial-sided fixation of soft tissue grafts in anterior cruciate ligament (ACL) reconstruction has often been identified as the weak link in the fixation construct, with interference screws being a commonly used technique. A significant concern surrounding the use of interference screws for soft tissue fixation is graft laceration and the possibility of loss of pull-out strength and slippage. The act of interference screw insertion for soft tissue graft fixation in ACL reconstruction alters the biomechanical properties of the graft.

Locking buttons increase fatigue life of locking plates in a segmental bone defect model.

Background: Durability of plate fixation is important in delayed union. Although locking plates result in stronger constructs, it is not known if locking affects the fatigue life of a plate. Two locking screws on either side of the nonunion could decrease working length and increase strain in the plate.