Thermal properties of polymethyl methacrylate vary depending on brand and type.

Polymethyl methacrylate (PMMA) is commonly used in orthopedic surgery and has several applications, most often for fixation of arthroplasty components. While its overall safety and tolerance are well described, less is known regarding the thermal properties of PMMA as it sets from a liquid to solid state, as well as the potential for osseous thermal necrosis. This study addresses potential variations in the setting time and maximum temperature of PMMA formulations in common use and explores the potential clinical implications of this variability.

Posteromedial Accessory Incision for Posterior Capsular Release and Retractor Placement in a Total Ankle Replacement.

The standard approach for performing a total ankle replacement (TAR) is the anterior approach as this offers good direct visualization of the tibiotalar joint. Irrespective of implant system used, most commonly, bone cuts are made in the anterior to posterior direction and may potentially injure the posterior neurovascular structures and tendons running close to the ankle joint. Careful consideration must be taken to ensure these structures are protected.

Comparison of Cruciate-Sacrificing vs Posterior-Stabilized Total Knee Replacement Using a Contemporary Total Knee System.

Background: The use of highly conforming polyethylene tibial inserts in cruciate-retaining total knee arthroplasty (TKA) often requires posterior cruciate ligament (PCL) release/sacrifice for balancing (CS TKA). The CS TKA relies on the posterior capsule, collateral ligaments, and articular conformity without a cam or post to achieve stability. Using prospectively collected data we compared clinical outcomes of CS TKA to posterior-stabilized (PS) TKA utilizing a contemporary TKA system.

Viscoelastic and failure properties of two configurations of triple-folded hamstring tendons used for anterior cruciate ligament (ACL) reconstruction.

Background: Hamstring autografts are commonly used for anterior cruciate ligament (ACL) reconstruction. Different folding techniques exist in tripling the semitendinosus. Few anatomical studies exist in evaluating their viscoelastic properties.

Supplementation of Lateral Locked Plating for Distal Femur Fractures: A Biomechanical Study.

Objectives: To investigate the biomechanical properties of a lateral locked plate alone or in combination with a supplemental medial plate or an intramedullary nail (IMN).

Methods: Intra-articular distal femur fractures with metaphyseal comminution (OTA/AO 33-C) were simulated with a standardized model in 28 synthetic femora and divided into 4 groups. Group I was instrumented with a 4.

Biomechanical Investigation of an Integrated 2-Screw Cephalomedullary Nail Versus a Sliding Hip Screw in Unstable Intertrochanteric Fractures.

Objective: To compare the efficacy of 2 intertrochanteric (IT) fracture fixation devices in conferring mechanical stability to unstable IT femur fractures.

Methods: Nine pairs of cadaveric female femurs with a groupwise average bone quality indicative of osteopenia were used. An unstable IT fracture without calcar support (OTA/AO 31-A2) was created and stabilized with either a sliding hip screw and side plate (SHS) or a cephalomedullary nail using an integrated dual-screw fixation [InterTAN (ITN)].

Long Segment Blocking Screws Increase the Stability of Retrograde Nail Fixation in Geriatric Supracondylar Femur Fractures: Eliminating the "Bell-Clapper Effect".

Objectives: To determine the change in stiffness and horizontal translations of a geriatric supracondylar femur fracture model with the addition of distal segment blocking screws versus proximal (long) segment blocking screws to the standard retrograde intramedullary nail construct.

Methods: Unstable supracondylar femur fractures (OTA/AO 33-A3) were created; all specimens were instrumented with a retrograde intramedullary nail. Specimens were divided into 2 groups (6 matched pairs per group).

Biomechanical Comparison of 3 Inferiorly Directed Versus 3 Superiorly Directed Locking Screws on Stability in a 3-Part Proximal Humerus Fracture Model.

Objective: To quantify the stability of 3 points of inferiorly directed versus 3 points of superiorly directed locking screw fixation compared with the full contingent of 6 points of locked screw fixation in the treatment of a 3-part proximal humerus fracture.

Methods: A standardized 3-part fracture was created in 10 matched pairs (experimental groups) and 10 nonmatched humeri (control group). Osteosynthesis was performed using 3 locking screws in the superior hemisphere of the humeral head (suspension), 3 locking screws in the inferior hemisphere (buttress), or the full complement of 6 locking screws (control).

Sensitivity and Specificity of Skyline and Carpal Shoot-Through Fluoroscopic Views of Volar Plate Fixation of the Distal Radius: A Cadaveric Investigation of Dorsal Cortex Screw Penetration.

Background: Volar plate fixation of distal radius fractures can result in soft tissue injuries. Abnormal contour of the dorsal cortex of the distal radius provides difficulties in discerning screw penetration on standard radiographs. The skyline and carpal shoot-through views are additional views to improve dorsal cortex visibility.

Radiographic evaluation of acute distal radius fracture stability: A comparative cadaveric study between a thermo-formable bracing system and traditional fiberglass casting.

Background: Distal radius fractures are common musculoskeletal injuries and many can be treated non-operatively with cast immobilization. A thermo-formable brace has been developed for management of such fractures, but no data exist regarding its comparative stabilizing efficacy to fiberglass casting.

Methods: A worst-case distal radius fracture was created in 6 cadaveric forearms.

Comparison of 3 Methods for Maintaining Inter-Fragmentary Compression After Fracture Reduction and Fixation.

Objectives: It is recommended that the intra-articular component of a supracondylar distal femoral fracture be stabilized by a lag screw to create interfragmental compression. Generally, it is thought that lag screw fixation should precede any positional screw or locking screw application. This study compared 3 methods of maintaining interfragmentary compression after fracture reduction with a reduction clamp.