Biomechanical Comparison of Nonlocked Minimally Invasive and Locked Open Achilles Tendon Simulated Rupture Repairs.

Background: Open repair of Achilles tendon ruptures is associated with a risk of infection and other wound complications. Although percutaneous repairs reduce these complications, they may increase the risk of nerve injury. This study was designed to determine whether a percutaneous nonlocking repair can approach the gapping resistance offered by a standard open repair under conditions approximating typical postoperative physiotherapy.

Biomechanical Effect on Joint Stability of Including Deltoid Ligament Repair in an Ankle Fracture Soft Tissue Injury Model With Deltoid and Syndesmotic Disruption.

Background: The current operative standard of treatment for bimalleolar equivalent ankle fracture is open reduction and internal fixation (ORIF) of the lateral malleolus followed by syndesmotic stabilization if indicated. There is controversy surrounding the indication and need for deltoid ligament repair in this setting. The purpose of this study was to quantify the biomechanical effect of deltoid ligament repair in an ankle fracture soft tissue injury model.

Soft Tissue Anchoring Performance, Biomechanical Properties, and Tissue Reaction of a New Hernia Mesh Engineered to Address Hernia Occurrence and Recurrence.

One opportunity to reduce hernia occurrence and recurrence rates (currently estimated to be 30% at 10 years postoperatively) is by enhancing the ability of hernia meshes to anchor into tissue to prevent mesh migration, mesh contraction, and mesh tearing away from tissue. To address this, we developed a novel moderate-weight, macroporous, polypropylene mesh (termed the T-line mesh) with mesh extensions to optimize anchoring. We examined the physical properties, biomechanical performance, and biocompatibility of this novel mesh versus a predicate mesh anchored with #0-suture.

Metacarpal Position and Lunate Facet Screw Fixation in Dorsal Wrist-Spanning Bridge Plates for Intra-Articular Distal Radial Fracture: A Biomechanical Analysis.

Background: A dorsal wrist-spanning plate (DWSP) can be affixed to the second or third metacarpal, depending on the morphology of the distal radial fracture (DRF) and on surgeon preference, but comparative biomechanical analyses between these methods are limited. This biomechanical study compared fixation to the second metacarpal versus the third metacarpal as measured by lunate facet fragment displacement in a cadaveric model of an axially loaded intra-articular DRF. The construct rigidity with the addition of an intrafragmentary lunate facet locking screw was also evaluated.

Application of a novel suture anchor to abdominal wall closure.

Background: Mesh suture used in high-tension wound closures produces large knots susceptible to increased palpability, infection, and foreign body response; yet has superior tensile strength and increased resistance to cutting through tissue compared to standard suture. This study investigates mesh suture fixation in abdominal tissue with a knotless novel, low-profile anchor-clip.

Methods: Single and double end fixation of mesh suture in swine rectus abdominus fascia with an anchor-clip, a knot, and predicate device fixation underwent cyclic testing followed by pull-to-failure testing.

Examining the viability of carbon fiber reinforced three-dimensionally printed prosthetic feet created by composite filament fabrication.

Background:: A low-cost, yet high-functioning, fabrication method for prosthetic components is needed to provide underserved amputee communities with quality mobility devices. Three-dimensional printing is a potential alternative, yet limitations in material characteristics have previously prevented the technology from emerging as a solution.

Objective:: To validate the application of a novel three-dimensional printing technique as a fabrication method for creating fiber composite patient end-use prosthetic feet.

Simultaneous Intraoperative Measurement of Cadaver Ankle and Subtalar Joint Compression During Arthrodesis With Intramedullary Nail, Screws, and Tibiotalocalcaneal Plate.

Background: Suboptimal tibiotalocalcaneal arthrodesis (TTCA) fusion rates may result from inadequate compression that increases motion and interferes with bony bridging. The aim of this study was to evaluate compressive forces at the ankle and subtalar joints with 3 contemporary TTCA constructs.

Methods: Thirty fresh-frozen cadaveric lower extremity specimens were divided into 3 groups of 10 each: 3 partially threaded cannulated screws, hindfoot nail, and lateral plate.

Modifying hernia mesh design to improve device mechanical performance and promote tension-free repair.

Purpose: Approximately 348,000 ventral hernia repairs are performed annually in the United States and the incisional hernia recurrence rate is approximately 20% as a result of suture and mesh device failure. Device failure is related to changes at the suture/tissue interface that leads to acute or chronic suture pull-through and surgical failure. To better manage mechanical tension, we propose a modified mesh design with extensions and demonstrate its mechanical superiority.

Torsional stiffness after subtalar arthrodesis using second generation headless compression screws: Biomechanical comparison of 2-screw and 3-screw fixation.

Background: Subtalar joint arthrodesis is a common operative treatment for symptomatic subtalar arthrosis. Because excessive relative motion between the talus and calcaneus can delay or prohibit fusion, fixation should be optimized, particularly in patients at risk for subtalar arthrodesis nonunion. Tapered, fully-threaded, variable pitch screws are gaining popularity for this application, but the mechanical properties of joints fixed with these screws have not been characterized completely.

Compressive Force With 2-Screw and 3-Screw Subtalar Joint Arthrodesis With Headless Compression Screws.

Background: Joint compression is an essential element of successful arthrodesis. Although subtalar joint compression generated by conventional screws has been quantified in the laboratory, compression obtainable with headless screws that rely on variable thread pitch to achieve bony contact has not been assessed. This study measured subtalar joint compression achieved by 2 posteriorly placed contemporary headless, variable-pitch screws, and quantified additional compression gained by placing a third screw anteriorly.

Effectiveness of Allograft Reconstruction vs Tenodesis for Irreparable Peroneus Brevis Tears: A Cadaveric Model.

Background: Irreparable peroneus brevis tendon tears are uncommon, and there is scant evidence on which to base operative treatment. Options include tendon transfer, segmental resection with tenodesis to the peroneus longus tendon, and allograft reconstruction. However, the relative effectiveness of the latter 2 procedures in restoring peroneus brevis function has not been established.

Systematic Quantification of Stabilizing Effects of Subtalar Joint Soft-Tissue Constraints in a Novel Cadaveric Model.

Background: Distinguishing between ankle instability and subtalar joint instability is challenging because the contributions of the subtalar joint's soft-tissue constraints are poorly understood. This study quantified the effects on joint stability of systematic sectioning of these constraints followed by application of torsional and drawer loads simulating a manual clinical examination.

Methods: Subtalar joint motion in response to carefully controlled inversion, eversion, internal rotation, and external rotation moments and multidirectional drawer forces was quantified in fresh-frozen cadaver limbs.

Biomechanical Comparison of Intramedullary Screw Versus Low-Profile Plate Fixation of a Jones Fracture.

Background: Intramedullary screw fixation of fifth metatarsal Jones fractures often produces satisfactory results, however, nonunion and refracture rates are not negligible. The low-profile "hook" plate is an alternative fixation method that has been promoted to offer improved rotational control at the fracture site, but this remains to be proven. The purpose of this study was to document biomechanical performance differences between this type of plate and a contemporary solid, dual-pitch intramedullary screw in a cadaveric Jones fracture model.

The influence of patient age and bone mineral density on osteotomy fixation stability after hallux valgus surgery: A biomechanical study.

Background: Oblique osteotomies of the first metatarsal are common surgical treatments for moderate to severe hallux valgus deformity. Osteotomy fixation integrity is important to minimize interfragment motion and maintain correction during healing, and our clinical observations suggest that patient age and bone quality affect fixation stability and ultimately the clinical outcome. Accordingly, this study correlated these patient factors with key mechanical measures of osteotomy angulation resistance in a cadaver hallux valgus correction model.

Biomechanical Comparison of External Fixation and Compression Screws for Transverse Tarsal Joint Arthrodesis.

Background: Transverse tarsal joint arthrodesis is commonly performed in the operative treatment of hindfoot arthritis and acquired flatfoot deformity. While fixation is typically achieved using screws, failure to obtain and maintain joint compression sometimes occurs, potentially leading to nonunion. External fixation is an alternate method of achieving arthrodesis site compression and has the advantage of allowing postoperative compression adjustment when necessary.

Comparison of Acute Histologic and Biomechanical Effects of Radiofrequency Ablation and Cryoablation on Periarticular Structures in a Swine Model.

Purpose: To compare the acute effects of radiofrequency (RF) ablation and cryoablation on the structural integrity of nontarget periarticular tissues that may be placed at risk during percutaneous bone ablation.

Materials And Methods: RF ablation and cryoablation were separately performed on tendon, articular cartilage, and ligament in an ex vivo porcine model by using standard bone ablation protocols. Gross and histopathologic analysis was performed on cartilage and tendon (n = 6 for each treatment group, n = 5 controls).

Calcaneal "Z" osteotomy effect on hindfoot varus after triple arthrodesis in a cadaver model.

Background: Triple arthrodesis involves subtalar, talonavicular, and calcaneocuboid joint fusion and is performed to relieve pain and correct deformity. Complications include malunion resulting in equinovarus and lateral column overload, which can lead to painful callosities and stress fractures. This study quantified the effectiveness of a closing-wedge calcaneal "Z" osteotomy for correction of the varus condition and reduction of abnormal loading of the lateral border of the foot.

Biomechanical assessment of flexible flatfoot correction: comparison of techniques in a cadaver model.

Background: Options for surgical correction of acquired flexible flatfoot deformity involve bone and soft-tissue reconstruction. We used an advanced cadaver model to evaluate the ability of key surgical procedures to correct the deformity and to resist subsequent loss of correction.

Methods: Stage-IIB flatfoot deformity was created in ten cadaver feet through ligament sectioning and repetitive loading.

Biomechanical comparison of prophylactic medial malleolar fixation in total ankle arthroplasty.

The purpose of this study was to compare the biomechanical properties of two common forms of prophylactic fixation of the medial malleolus during total ankle arthroplasty (TAA). Ten matched pairs of cadaveric lower extremities were fixed with a single cannulated cortical screw or a one-third tubular plate after preparation for TAA. Ten unmatched single cadaver lower extremities were used as the control.

Biomechanical comparison of 4 different lateral plate constructs for distal fibula fractures.

Background: Displaced lateral malleolar fractures are often treated with reduction and surgical stabilization. However, there has not been a comprehensive laboratory comparison to determine the most appropriate device for treating these patients. This study subjected a range of contemporary lateral fibular plates to a series of mechanical tests designed to reveal performance differences.

A biomechanical analysis of two anterior ankle arthrodesis systems.

Background: An increasingly popular ankle fusion method uses plates and screws positioned on the anterior aspect of the tibiotalar joint. This study compared the mechanical properties of 2 contemporary plate systems for ankle arthrodesis, one based on a single anterior plate and the other comprising paired anteromedial and anterolateral plates.

Methods: Ten matched pairs of fresh-frozen cadaver ankle joints underwent arthrodesis with a single anatomically contoured anterior plate or 2 anatomic plates applied anteromedially and anterolaterally.

Compression screw fixation of the syndesmosis.

Background: Screw fixation of syndesmotic injuries facilitates ligament healing and restoration of ankle stability, but little information regarding screw performance is available. This study quantified the reduction obtained with three common 2-screw configurations using different methods of reduction and novel methods of subsequently provoking and measuring diastasis.

Methods: Seven fresh-frozen lower extremities were subjected to 100 N medial and lateral tibia loads with the talus restrained.

Shortcuts in arthroscopic knot tying: do they affect knot and loop security?

Background: Shortcuts for throwing 3 alternating reversed half-hitches on alternating posts (RHAPs), in which the post is switched by alternating strand tension to "flip" the knot, have been advocated but never validated in a biomechanical study.

Hypothesis: Shortcut tying techniques will affect knot security or loop security.

Study Design: Controlled laboratory study.

Jones fracture fixation: a biomechanical comparison of partially threaded screws versus tapered variable pitch screws.

Background: Stabilization of fifth metatarsal Jones fractures with intramedullary screw fixation is the most common method for surgical fixation when operative treatment is indicated. Conventional partially threaded screws of various diameters are routinely used for Jones fracture fixation. Recently, the use of tapered variable pitch screws has become popular, but information regarding their performance in Jones fracture fixation is limited.

Effect of graft height mismatch on contact pressures with osteochondral grafting of the talus.

Background: Osteochondral allograft transplantation is technically demanding. It is not always possible to place the surface of the graft perfectly flush with the surrounding cartilage. One must often choose between placing at least some portion of the surface of the graft slightly elevated or recessed.