A quantitative analysis of two cementing techniques in total elbow replacement: A cadaveric study

One of the reasons for failure of total elbow replacement is loosening of the ulnar component. Cementing techniques are often outdated. A special small nozzle is needed for the ulnar component, when a cement gun is used. This may not always be available, or surgeons may prefer to use a syringe. We postulated that the use of a cement gun and smaller nozzle would result in improved filling of the ulnar canal. A cadaveric study was performed in which the ulnas of paired specimens were cemented with a cement gun or with a syringe. A 3D printed ulnar component was inserted and computed tomography scanning was performed on all specimens. Filling of the ulnar intramedullary canal was analysed using 3D reconstructions of the specimens. A greater degree of filling was seen by the use of the cement gun in 85.7%. Filling was 52.7% in the syringe group (25.1–78.7%), compared to 63.3% for the cement gun group ( p < 0.05). The use of a small nozzle cement gun provided a significantly higher filling degree of the ulnar canal. We recommend to always use a cement gun with a specific small nozzle to cement the ulnar component in total elbow arthroplasty.

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Morphology and performance of the ‘trap-jaw’ cheliceral strikes in spiders (Araneae, Mecysmaucheniidae)

Journal of Experimental Biology ◽

10.1242/jeb.219899 ◽

2020 ◽

Vol 223 (14) ◽

pp. jeb219899 ◽

Cited By ~ 2

Author(s):

Hannah M. Wood

Keyword(s):

High Speed ◽

Micro Computed Tomography ◽

Kinematic Data ◽

Computed Tomography Scanning ◽

Structural Differences ◽

Angular Velocities ◽

Spring System ◽

3D Printed ◽

And Performance ◽

Tomography Scanning

ABSTRACTMecysmaucheniidae spiders have evolved ultra-fast cheliceral strikes 4 times independently. The mechanism for producing these high-speed strikes is likely due to a latch/spring system that allows for stored energy to be rapidly released. This study examined two different sister lineages: Zearchaea has ultra-fast cheliceral strikes and Aotearoa, based on external morphology of the clypeus, is hypothesized to have slower strikes. Using high-speed videography, I first gathered kinematic data on each taxon. Then, using histology and data from micro-computed tomography scanning, I examined internal cheliceral muscle morphology to test whether shifts in muscle anatomy correspond to performance differences in cheliceral strike. Results from high-speed video analysis revealed that Zearchaea achieves peak angular velocities of 25.0×103±4.8×103 rad s−1 (mean±s.d.) in durations of 0.0843±0.017 ms. The fastest recorded strike had a peak angular and linear velocity of 30.8×103 rad s−1 and 18.2 m s−1, respectively. The slower striking sister species, Aotearoa magna, was three orders of magnitude slower in velocity and longer in duration. Histology revealed sarcomere length differences, with some muscles optimized for force, and other muscles for speed. 3D printed models revealed structural differences that explain how the chelicerae hinge open and close. Combining all of this evidence, I put forth a hypothesis for the ultra-fast trap-jaw mechanism. This research documents the morphological shifts that accompany ultra-fast movements that result in increased rotation in joints and increased muscle specialization.

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Intramedullary fibula strut bone allograft in a periprosthetic humeral shaft fracture with implant loosening after total elbow arthroplasty

Clinics in Shoulder and Elbow ◽

10.5397/cise.2020.00213 ◽

2020 ◽

Vol 23 (3) ◽

pp. 152-155

Author(s):

Young-Hoon Jo ◽

Seung Gun Lee ◽

Incheol Kook ◽

Bong Gun Lee

Keyword(s):

Internal Fixation ◽

Periprosthetic Fracture ◽

Fracture Site ◽

Implant Loosening ◽

Cerclage Wire ◽

Replacement Surgery ◽

Total Elbow Replacement ◽

Intramedullary Canal ◽

Elbow Replacement ◽

Fibula Strut

Periprosthetic fracture after total elbow replacement surgery is a difficult complication to manage, especially when it comes together with implant loosening. If stem revision and internal fixation of the periprosthetic fracture are performed simultaneously, this would be a very challenging procedure. Most of total elbow replacement implants are cemented type. Cement usage at periprosthetic fracture site may interfere healing of fractured site. Authors underwent internal fixation with use of locking plate and cerclage wire for periprosthetic fracture, allogenous fibular strut bone inserted into the humerus intramedullary canal allowing the fractured site to be more stable without cement usage. At 10-month follow-up, the complete union and good clinical outcome was achieved. We present a novel technique for treating periprosthetic fracture with implant loosening after total elbow replacement surgery, using intramedullary allogenous fibula strut bone graft.

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