Biomechanical evaluation of spiral fracture in human metacarpal using chicken humerus model.

Introduction: Animal bones have been used as a model to mimic human bones for investigation of fracture patterns and fixation techniques. This study aims to investigate the effects of torsional forces of varying speeds on the spiral fracture in human metacarpal using a chicken humerus model.

Materials And Methods: Thirty fresh-frozen chicken humerus bones were dissected and equally divided into three groups.

Comparing the torsional resistance of different fixation techniques for spiral metacarpal fractures.

This study aimed to compare the torsional resistance of three fixation techniques for spiral metacarpal fractures: screw-only fixation, screw plus neutralization plate fixation, and a locking plate construct. A spiral fracture was created on 18 cadaveric metacarpal bones by applying an axial and torsional loading force using an Instron 3343 mechanical tester. The failure strength was defined as the native torque strength.

Biomechanical Study of Asymmetric Flexor Tendon Repair Using a 6-Strand 4-0 Supramid Suture Versus a 4-Strand 2-0 Tenoflex Suture.

Multi-strand repair of flexor tendons are important for increased strength but this may cause ischemia during the intrinsic healing process. In this study, we aim to compare the strength of the 4-strand modified Asymmetric repair using 2-0 Tenoflex suture with the original description of the Asymmetric repair using a 6-strand 4-0 Supramid suture under cyclic loading in a porcine tendon model. We hypothesise that the number of core sutures through the repair site can be reduced with advanced suture material.

A fluid-structure interaction investigation of intra-articular pressure and ligament in wrist joint.

Understanding the stresses on the scapholunate interosseous ligament (SLIL) and its interaction with synovial fluid pressure could be vital to improve wrist treatment for various wrist conditions such as arthritis, sprains and tendonitis. This study investigated the interaction between the intra-articular pressure, specifically the synovial fluid pressure change and the SLIL stresses in a computational model during wrist radioulnar deviation (RUD). Magnetic resonance imaging (MRI) scans were used to acquire the anatomical model of the carpal bones and ligament, while the kinematics of scaphoid and lunate were obtained through dynamic computerized tomography (CT) scans.

Biomechanical Study of Modified Massachusetts General Hospital Flexor Tendon Repair Using Looped Sutures.

Massachusetts General Hospital (MGH) repair is one of the widely used 4-strand flexor tendon repair techniques. However, it uses two single strand sutures that are each passed twice across the repair site. This is time consuming and may cause imbalance of the load across the repair.

A Biomechanical Comparison of Gliding Resistance between Modified Lim Tsai and Asymmetric Tendon Repair Techniques in Zone II Flexor Tendon Repairs.

Early active motion protocols have shown better functional outcomes in zone II flexor tendon lacerations. Different techniques of tendon repair have different effects on gliding resistance, which can impact tendon excursion and adhesion formation. For successful initiation of early active mobilisation, the repair technique should have high breaking strength and low gliding resistance.

Biomechanical Study of Asymmetric Flexor Tendon Repair Using 3 Different Suture Materials.

: The asymmetric technique for flexor tendon repairs has various advantages but further improvement is possible by using a suitable suture material. In this study, we compare the biomechanical performance of asymmetric repairs using 3 suture materials: Supramid Extra II 4-0, Tendo-Loop 4-0, and FiberLoop 4-0. : We divided 30 porcine flexor tendons into 3 arms.

Intramedullary nailing confers an increased risk of medial migration compared to dynamic hip screw fixation in unstable intertrochanteric hip fractures.

Introduction: Medial migration of the femoral neck element (FNE) superomedially against gravity with respect to the intramedullary component of the cephalomedullary nail is a complication increasingly recognized to cause femoral head cut-out in intramedullary nailing of pertrochanteric hip fractures. Although cut-outs are common to both intra- and extramedullary fixation, especially in unstable pertrochanteric hip fractures, FNE medial migration in sliding hip screws continues to remain sparse despite increased awareness of the phenomenon. This study aims to investigate whether intramedullary nailing is biomechanically predisposed to FNE medial migration compared to extramedullary fixation with sliding hip screws to account for the discrepancy in reported FNE medial migration rates.

Evaluation of femtosecond laser-assisted anterior capsulotomy in the presence of ophthalmic viscoelastic devices (OVDs).

The introduction of femtosecond laser-assisted cataract surgery is an alternative approach to conventional cataract surgery. Our study aimed to determine the effectiveness of femtosecond laser-assisted capsulotomy in the presence of different ophthalmic viscoelastic devices (OVDs) in the anterior chamber. Fresh porcine eyes (n = 96) underwent LDV Z8-assisted anterior capsulotomy, either in the presence of an OVD (Viscoat, Provisc, Healon, Healon GV or HPMC) or without, using 90% and 150% energies respectively.

Biomechanical comparison of vertical suture techniques for repairing radial meniscus tear.

Purpose: The aim of this study was to (1) develop suture techniques in repairing radial meniscal tear; (2) to compare the biomechanical properties of the proposed repair techniques with the conventional double horizontal technique.

Methods: Thirty-six fresh-frozen porcine medial menisci were randomly assigned into four groups and a complete tear was made at the midline of each meniscus. The menisci were subsequently repaired using four different repair techniques: double vertical (DV), double vertical cross (DVX), hybrid composing one vertical and one horizontal stitch, and conventional double horizontal (DH) suture technique with suturing parallel to the tibia plateau.

Biomechanical comparison of monocortical and bicortical plate fixation for rib fractures in a cadaveric model using a locking plate system.

Background: Surgical stabilization of rib fractures is an established form of treatment for complex rib fractures. Plate fixation with bicortical screws placement can cause injury to intra-thoracic organs and pleural irritation from protruding screw tips. The aim of this study is to compare the biomechanical properties of monocortical and bicortical plate fixation for rib fractures using a locking plate system.

A review of cyclic testing protocols for flexor tendon repairs.

Background: Cyclic testing of flexor tendons aims to simulate post-operative rehabilitation and is more rigorous than static testing. However, there are many different protocols, making comparisons difficult. We reviewed these protocols and suggested two protocols that simulate passive and active mobilization.

The Effect of Suture Materials on the Biomechanical Performance of Different Flexor Tendon Repairs and the Concept of Construct Efficiency.

Background: To propose a new term ('construct efficiency') for the evaluation of multi strands flexor tendon repairs using different suture materials.

Methods: A total of twenty specimens from 4-0 braided polyblend sutures (FiberLoop/FiberWire; Arthrex, Naples, FL) and 4-0 nylon sutures (Supramid Extra II; S. Jackson, Inc.

Biomechanical comparison of modified Lim/Tsai tendon repairs with intra- and extra-tendinous knots.

We compared the Lim/Tsai tendon repair technique using an extra-tendinous knot with modification using an intra-tendinous knot. The ultimate tensile strength, load to 2 mm gap force, stiffness, mode of failure, location of failure, and time taken to repair each tendon were recorded during a single cycle loading test in 20 tendons with each repair method. We found that the ultimate tensile strength and 2 mm gap force of the modified Lim/Tsai repair with an extra-tendinous knot (56 SD 5 N and 14 SD 2 N, respectively) were statistically significantly higher than that of the modified Lim/Tsai repair with intra-tendinous knot (51 SD 7 N and 11 SD 2 N, respectively).

Performing Reliable Lens Capsulotomy in the Presence of Corneal Edema With a Femtosecond Laser.

Purpose: To determine the effects of the Ziemer LDV Z8 liquid interface femtosecond laser platform during capsulotomy under different energy settings in the presence of corneal edema.

Methods: Cadaveric porcine eyes (n = 36) employed at less than 6 and greater than 24 post enucleation hours to simulate clear/edematous corneas, underwent capsulotomy with the Ziemer LDV Z8 femtosecond laser (5-mm diameter, energy 90%, 130%, or 150%). Lens capsules were removed for evaluation by scanning electron microscopy and rupture strengths determined by the single column universal testing system.

Biomechanical comparison of the Lim/Tsai tendon repair with a modified method using a single looped suture.

The Lim/Tsai tendon repair technique has been modified clinically to achieve a 6-strand repair using a single looped suture with one extratendinous knot. We compared biomechanical performance of the original and modified methods using 20 porcine flexor digitorum profundus tendons. The ultimate tensile strength, load to 2 mm gap force, mode of failure, and time taken to repair each tendon were recorded during a single cycle loading test in 10 tendons with each repair method.

A Biomechanical Study of a Novel Asymmetric 6-Strand Flexor Tendon Repair Using Porcine Tendons.

Background: This study evaluated the biomechanical performance of a novel asymmetric 6-strand flexor tendon repair technique without locking loops.

Methods: Twenty porcine flexor tendons were equally repaired by using the asymmetric technique and compared with the modified Lim-Tsai repair technique. The ultimate tensile strength, load to 1-mm gap force, stiffness, and mechanism of failure were measured.

The effects of a low-energy, high frequency liquid optic interface femtosecond laser system on lens capsulotomy.

The introduction of femtosecond laser assisted cataract surgery (FLACS) is a paradigm changing approach in cataract surgery, the most commonly performed surgical procedure. FLACS has the potential to optimize the creation of an anterior lens capsulotomy, a critical step in accessing the cataractous lens. The merits of using a laser instead of a manual approach include a potentially more circular, consistent, and stronger aperture.