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Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 230 - 230
1 Jul 2014
Nicolescu R Ouellette E Clifford P Kam C Sawardeker P Latta L
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Summary

Practitioners should maintain a high suspicion of concurrent carpal fractures in patients who present with a distal radius fracture after a fall onto an outstretched hand, particularly if forearm rotation is involved.

Introduction

Simultaneous scaphoid and distal radius fractures, and the importance of their identification, have been previously described in multiple reports. However, few studies have investigated the incidence of carpal fractures, in general, occurring concurrently with distal radius fractures after a common mechanism of wrist injury. The purpose of this study is to investigate the incidence and characteristics of carpal fractures occurring simultaneously with distal radius fractures after a fall onto an outstretched hand. We hope to determine whether different fall parameters, such as hand position and forearm rotation, influence the frequency of this injury.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 270 - 270
1 Jul 2014
Elliott W Kaimrajh D Sawardeker P Milne E Ouellette A Latta L
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Summary

The significance of matching radius of curvature of the radial head implant and the capitellum in implant selection is evaluated. A mismatch of radius of curvature could lead to point loading, reducing contact area, creating large contact stresses, resulting in arthritis, pain, and other complications.

Introduction

Radial head (RH) implant size is chosen by reconstruction outside of the radiocapitellar joint capsule measuring the RH diameter and length, which is replicated for implant selection. RH radius of curvature (RC) is rarely part of the decision although important in determining contact area.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 232 - 232
1 Jul 2014
Ouellette E Elliott W Latta L Milne E Kaimrajh D Lowe J Makowski A Herndon E Kam C Sawardeker P
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Summary

For injuries to the lower leg or forearm, supplemental support from soft tissue compression (STC) with a splint or brace-like system and combined with external fixation could be done effectively and quickly with a minimal of facilities in the field.

Introduction

Soft tissue compression (STC) in functional braces has been shown to provide rigidity and stability for most closed fractures, selected open fractures and can supplement some other forms of fracture fixation. However, soft tissue injuries are compromised in war injuries. This study was designed to evaluate if STC can provide adequate rigidity and stability either with, or without other forms of fixation techniques of simple fractures or bone defects after standardised soft tissue defects. The load was applied either axially or in bending as the bending configuration is more like conditions when positioned on a stretcher in the field.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 272 - 272
1 Jul 2014
Elliott W Sawardeker P Kam C Ouellette A Latta L
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Summary

Increased lateral ulnotrochlear joint space due to improper sizing in radial head arthroplasty may result in medial collateral ligament laxity, leading to increased osteophytes and arthritis.

Introduction

Radial head (RH) arthroplasty is a common response to comminuted RH fractures. Typical complications include improper sizing, leading to changes in joint kinematics. Evidence of these changes should be visible through fluoroscopic images of affected joints. The two examined changes in this study are the ulnar deviation from distal radial translation (DRT), and the widening of the lateral ulnotrochlear joint space (LUT).


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 229 - 229
1 Jul 2014
Nicolescu R Ouellette E Kam C Sawardeker P Clifford P Latta L
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Summary

When a TFCC tear is diagnosed, practitioners should maintain a high level of suspicion for the presence of a concomitant SL or LT ligament tear.

Introduction

Disruption of the scapholunate (SL) or lunotriquetral (LT) ligament leads to dorsal and volar intercalated segment instability, respectively, while triangular fibrocartilage complex (TFCC) tears result in distal radioulnar joint (DRUJ) instability. Viegas et al. (1993) demonstrated that 56% of grossly visualised cadaveric wrists had one or more tears of a ligament or of the TFCC. The purpose of this investigation is to quantify the incidence, distribution, and correlation of SL, LT, and TFCC tears in a large group of cadaver wrists using magnetic resonance imaging (MRI). Additionally, statistical analysis was performed to predict.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 271 - 271
1 Jul 2014
Elliott W Sawardeker P Kaimrajh D Kam C Milne E Ouellette A Latta L
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Summary

Consistent load distributions with over-sizing of radial head implants show minimal variance in interosseus ligament (IOL) and triangular-fibrocartilage complex (TFCC) tension, both of which are essential in distribution of load at the elbow.

Introduction:Changes in loading distribution at the elbow have not been studied with radial head (RH) arthroplasty. Difficulty arises concerning distribution variability between loading methods and magnitudes, and with implant oversizing.

Method

RC joint capsule were exposed using the Kocher approach in seven fresh-frozen cadaver Humeri. Specimens were loaded axially in an MTS machine with humeri at 90° and wrist neutral. The arms were cycled in load control between 13N–130N until steady-state was reached for each trial. After loading in neutral, the arms were rotated to 60° supination (60S) and 60° pronation (60P), the test repeated. The radial head was excised and Co-Cr implant inserted. Sizings 0mm, +2mm, +4mm were simulated using 2mm plastic spacers on the stem. A Tekscan pressure map transducer at RC recorded loading. The recorded Tekscan loads were organised according to sizing (native, 0mm, +2mm, +4mm) for each specimen. The max/min load values were recorded and the difference, ΔL was calculated. The Max and ΔL values from each sizing were percentage paired with the respective native value. The ΔL values were used to discern load distribution. A linear regression was done using the RC loading plotted against the applied load to visualise the change of load distribution with changing applied loads. Data was analyzed using one-way analysis of variance.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 523 - 523
1 Dec 2013
Latta L Sawardeker P Kam C Milne E Ouellette E
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INTRODUCTION:

Radial head arthroplasty is a reliable procedure with good functional outcomes when faced with irreparable radial head fractures. Since the first attempt at arthroplasty by Speed in 1941, there have been a variety of different designs created for radial head prostheses. There has been considerable recent interest in bipolar radial head components. However, to date, there have been few biomechanical studies comparing bipolar components to their monopolar counterparts. We examine the effects of alteration of axial length of the radial head prosthesis and force conveyed at the radiocapitellar joint in a head-to-head comparison of bipolar implants to monopolar implants.

METHODS:

Sixteen fresh-frozen, sided cadaveric arms were utilized. Radial heads were resected and either a monopolar, rigid, metal radial head prosthesis (Solar, Stryker, Mahwah, NJ) was implanted or a bipolar metal prosthesis used (Katalyst, Integra, Plainsboro, NJ). Adjustments of radial head length were made in 2 mm increments using radiolucent washers to create an understuffed (−2), neutral (0), and overstuffed (+2, +4) effect, see Fig. 1. Forearms were cyclically loaded in compression from 13N to 130N with the forearm in neutral. Radiocapitellar forces were measured using Tekscan (Tekscan, Inc., Boston, MA) pressure sensors with radial head length set at −2 mm, 0, +2 mm and +4 mm and comparisons were made with the neutral (0) radial head, see Fig. 2. Multivariant ANOVA with Tukey's HSD correction was used for statistical analysis.


The Journal of Bone & Joint Surgery British Volume
Vol. 88-B, Issue 2 | Pages 141 - 148
1 Feb 2006
Sarmiento A Latta L