Biomechanical comparison of composite and cadaveric humeri models in experiments on operated humeral shaft fractures.

A study was undertaken to determine how well contacting fracture fragments of composite bone replicated the behavior of fracture fragments in real bone. Ten composite and ten real humeral diaphyses were transected and reconstructed with limited-contact dynamic-compression plates. Two screws were placed on each side of the transection site and a calibrated electronic sensor sheet was placed between the imitated fracture fragments.

Biomechanical analysis of single-incision anatomic repair technique for distal biceps tendon rupture using tunneling device.

Hypothesis: Single-incision biceps tendon repair with an arthrotunneling device has previously been shown to be a safe and effective technique that provides the anatomic restoration of a two-incision approach and a reduced complication profile. This repair provides adequate and comparable fixation to repairs utilizing anchors, buttons, screws, etc., at a lower cost.

Shear wave elastography ultrasound does not quantify mechanical properties of the ulnar collateral ligament of the elbow.

Objective: To validate shear wave elastography (SWE) stiffness measurements for the ulnar collateral ligament (UCL) of the elbow compared to mechanical measurements.

Materials And Methods: Eleven fresh frozen human cadaveric upper extremities were evaluated by a musculoskeletal-specialized radiologist to provide SWE measurements used to calculate stiffness at 4 points along the anterior band of the UCL at various load states and flexion angles. Specimens were then dissected and optical markers were placed on the UCL to track displacement during applied force by a load frame, thereby providing measurements to calculate the mechanical stiffness.

Stability, deformity, and fixation of the floating shoulder: a cadaveric biomechanical study.

Background: Floating shoulder injuries cause instability and deformity due to disruptions of the scapula, clavicle, and superior shoulder suspensory complex ligaments (SSSC). Resulting deformity of the glenopolar angle (GPA) has not previously been established, nor has the impact on stability and deformity when surgical fixation is performed. This study sought to quantify stability and deformity for multiple injury patterns and the improvement to these parameters provided by clavicle and coracoclavicular (CC) ligament fixation.

A biomechanical comparison of superior ramus plating versus intramedullary screw fixation for unstable lateral compression pelvic ring injuries

Introduction: Management of the anterior component of unstable lateral compression (LC) pelvic ring injuries remains controversial. Common internal fixation options include plating and superior pubic ramus screws. These constructs have been evaluated in anterior-posterior compression (APC) fracture patterns, but no study has compared the two for unstable LC patterns, which is the purpose of this study.

Biomechanical analysis of stability of joint depression calcaneal fractures: Fixation with locking compression plate alone compared with addition of supplemental oblique screw.

Purpose: The standard treatment of calcaneus fractures is a lateral plate and screw construct. Patients at our institution have been treated with a lateral locking plate combined with one retrograde screw inserted in the oblique plane to allow immediate weight bearing. The purpose of this study was to determine whether addition of a oblique screw to a lateral plate construct increases stability.

Conduit/Wrap Repairs to Digital Nerves Provide Residual Strength After Peak Loading.

Background: Many techniques are used for digital nerve repair, most commonly coaptation by sutures. Nerve repairs must be strong while offering an environment for nerve regeneration. Sutures can damage the nerve and thereby limit growth and regeneration.

Valgus fatigue and nonlinear damage accretion of the anterior bundle of the elbow medial collateral ligament (AMCL).

Failure by fatigue is one mechanism by which ligaments can rupture, with the accumulation of damage gradually degrading the ligament strength. Baseball pitchers who perform repeated high-level throwing continuously subject the medial ligament complex of the elbow to extreme levels of loading, which can lead to fatigue and eventual rupture. This study sought to investigate this behavior and quantify the fatigue properties of the anterior bundle of the medial collateral ligament (AMCL) with respect to valgus elbow torque.

Avoiding the blood supply to the femoral head during cannulated screw fixation: A comparison of two techniques.

Objectives: To compare the strength of the inverted triangle (IT) versus the L-shaped cannulated screw fixation technique for stabilizing a Pauwels 2 femoral neck fracture. To demonstrate the risk to the blood supply to the femoral head from a posterior-superior screw.

Methods: The IT construct was compared with the L-shaped design in 10 composite femurs.

Fibrin Glue and Conduit Form a Composite Structure in Digital Nerve Repair.

Repair of severed nerves without autograft or allograft has included suture, suture with glue alone, suture with conduit and suture with glue augmentation to conduit, where use of conduit is considered for separation of the nerve ends from 5 mm to 3 cm. Repairs must not only serve acutely to provide apposition of nerve ends but must enable the healing of the nerve. Using biological conduit can place suture at the ends of the conduit while fibrin glue alone eliminates suture but with limited strength.

Biomechanical Analysis of Ideal Knee Flexion Angle for ACL Graft Tensioning Utilizing Multiple Femoral and Tibial Tunnel Locations.

Anterior cruciate ligament (ACL) graft failure rate has been reported to be greater than 5% at 5 years. Our study evaluated ACL excursion with anatomic and nonanatomic femoral and tibial tunnels to determine optimal flexion angle to tension the ACL to minimize excursion. Ten cadaveric knee specimens were used.

Does Provisional Minifragment Fixation Prevent Compression With Dynamic Compression Plating? A Biomechanical Analysis.

Objectives: To compare the compressive force generated by a 3.5-mm compression plate with and without provisional fixation using a 2.0-mm minifragment plate.

Biomechanical Testing of a Transmetatarsal Base Screw in Lisfranc Injuries.

Objectives: To compare displacement between the cuneiforms and metatarsals for a typical Lisfranc screw and a transmetatarsal base screw under biomechanical loading.

Methods: Eight pairs of cadaveric feet (16 total) were evaluated. The Lisfranc ligamentous structures were transected in all specimens.

Medial Plating of Pauwels Type III Femoral Neck Fractures Decreases Shear and Angular Displacement Compared with a Derotational Screw.

Objectives: The purpose of this mechanical study was to compare 2 methods of augmented stabilization of Pauwels type III femoral neck fractures.

Methods: Ten matched pairs of young cadaveric femurs were cut 22 cm distal to the lesser trochanter. All specimens received a 70-degree osteotomy, which was stabilized with a 135-degree sliding hip screw.

The moving valgus stress test produces more ulnar collateral ligament change in length during extension than during flexion: a biomechanical study.

Hypothesis And Background: Injuries to the elbow medial ulnar collateral ligament (mUCL) pose a diagnostic challenge, with the moving valgus stress test (MVST) currently accepted as the gold-standard clinical test. This study sought to biomechanically evaluate the change in length of the ulnar collateral ligament (UCL) during flexion-extension using a null hypothesis that the mUCL will not experience a greater change in length with movement than with static loading.

Methods: Seven fresh-frozen human cadaveric elbows were tested with static and dynamic valgus stress.

Median and Digital Nerve In Situ Tension in the Hand.

Digital nerves will experience tension under normal daily activities, and understanding the amount of tension experienced in these nerves relates directly to the necessary strength in nerve repairs. To begin quantification of tension, the tension borne by the median and digital nerves in cadaveric hands was quantified under conditions of finger hyperextension, nerve distraction, and finger flexion. Five cadaveric hands were mounted in a special fixture that allowed finger hyperextension and flexion and could apply known distractions while the tension borne by each digital nerve was measured.

Biomechanical Response to Distraction of Hip Capsular Reconstruction With Human Acellular Dermal Patch Graft.

Purpose: To quantify the biomechanical properties of the hip capsule with human dermal allograft reconstruction to determine whether a dermal patch restored capsular resistance to distraction.

Methods: Nine cadaveric hip specimens were dissected until capsule and bony structures remained and were then mounted in a testing fixture in neutral flexion and abduction. Four states of the hip capsule were sequentially tested under axial distraction of 5 mm measured with video analysis and with resultant force measurement: (1) intact hip capsule, (2) interportal capsulotomy, (3) capsulectomy to the zona orbicularis, and (4) capsular reconstruction with human dermal allograft using acetabular anchors and capsule-to-patch sutures.

Correlation of Force to Deformation of the Anterior Bundle of the Medial Collateral Ligament Through Consideration of Band Laxity.

The anterior bundle of the medial collateral ligament (AMCL) resists the loads that arise at the elbow during overhand throwing and has commonly been divided into posterior and anterior bands. While these anterior and posterior bands have been thought to bear the load at different flexion angles, any transition of the load distribution between the two bands is poorly understood and has not considered laxity (slack). This study considers the AMCL as three bands and quantifies the mechanical response to vertical distraction, simulating valgus-load joint opening, through the sequential superposition of the band responses after the elimination of inherent laxity.

Assessment of Conduit-Assisted Primary Nerve Repair Strength With Varying Suture Size, Number, and Location.

Outcomes following digital nerve repair are suboptimal despite much research and various methods of repair. Increased tensile strength of the repair and decreased suture material at the repair site may be 2 methods of improving biologic and biomechanical outcomes, and conduit-assisted repair can aid in achieving both of these goals. Ninety-nine fresh-frozen digital nerves were equally divided into 11 different groups.

The optimal number and location of sutures in conduit-assisted primary digital nerve repair.

We evaluated the strength of conduit-assisted primary digital nerve repairs, with varying suture location and number, in 56 digital nerves from cadavers. Maximum load to failure was tested for the following seven repairs, designated by the number of epineurial sutures followed by the number of sutures at each end of the conduit: 4 (epineurial sutures)/0 (sutures at each end of conduit), 4/4, 4/2, 2/2, 0/4, 0/2, 0/1. The 4/4 repair (3.

Cadaveric Biomechanical Analysis of 3 Lateral Ulnar Collateral Ligament Reconstructions.

Objective: To biomechanically assess the angular stability provided by 3 techniques for reconstruction of the lateral ulnar collateral ligament.

Methods: Eight cadaveric elbows were tested with the lateral collateral ligament complex intact, disrupted from the origin at the lateral epicondyle, and reconstructed with 3 different techniques using ulnar bone tunnels: a suture "lasso" or palmaris longus tendon "lasso" both docked with a metal button at the origin, and a doubled-over palmaris longus tendon docked with metal buttons at both the origin and ulnar insertion. Elbows were tested with a physiologic elbow simulator, and varus angular position was quantified with an optical tracking system.

Fibrin Glue Increases the Tensile Strength of Conduit-Assisted Primary Digital Nerve Repair.

Background: An ideal peripheral nerve repair construct does not currently exist. Our primary goal was to determine whether fibrin glue adds to the tensile strength of conduit-assisted primary digital nerve repairs. Our secondary goal was to evaluate the impact of varying suture number and location on the tensile strength.

Comparing Biomechanical Properties, Repair Times, and Value of Common Core Flexor Tendon Repairs.

Background: The aim of the study was to compare biomechanical strength, repair times, and repair values for zone II core flexor tendon repairs.

Methods: A total of 75 fresh-frozen human cadaveric flexor tendons were harvested from the index through small finger and randomized into one of 5 repair groups: 4-stranded cross-stitch cruciate (4-0 polyester and 4-0 braided suture), 4-stranded double Pennington (2-0 knotless barbed suture), 4-stranded Pennington (4-0 double-stranded braided suture), and 6-stranded modified Lim-Tsai (4-0 looped braided suture). Repairs were measured in situ and their repair times were measured.

Weight-bearing recommendations after first metatarsophalangeal joint arthrodesis fixation: a biomechanical comparison.

Background: This study sought to determine whether several metatarsophalangeal (MTP) fusion techniques require complete immobilization or if some level of weight-bearing could be recommended after surgery. A comparison of synthetic composite to actual bone was included in order to examine the validity of the testing conditions.

Methods: Four MTP fusion modalities were tested in synthetic composite bone models: unlocked plating, locked plating, crossed lag screws, and an unlocked plate with a single lag screw.