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Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXIX | Pages 156 - 156
1 Sep 2012
Lammin K Taylor J Zenios M
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Background

Osteomyelitis can be difficult to diagnose. Unlike septic arthritis no defined diagnostic criteria exist as a guide. Inflammatory markers are frequently utilized at initial presentation, (in addition to white cell count).

Methods

All radiologically confirmed cases of long bone osteomyelitis without septic arthritis, joint effusion or abscess, in paediatric patients, presenting to one hospital over an eighteen-month period were included. These patients were compared with all culture positive septic arthrides presenting to the same hospital within the same time period. Inflammatory markers taken on the day of admission were studied.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXIX | Pages 60 - 60
1 Sep 2012
Taylor J Knox R Guyver P Czipri M Talbot N Sharpe I
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Background

Tibiotalocalcaneal arthrodesis is an important salvage method for patients with complex hindfoot problems including combined arthritis of the ankle and subtalar joints, complex hindfoot deformities and failed total ankle arthroplasty. The aim of this study was to report the elective results of combined subtalar and ankle arthrodesis using one design of dynamic retrograde intramedullary compression nail-the T2 Ankle Arthrodesis Nail(Stryker)

Methods

Retrospective review identified 53 consecutive patients who had 55 tibiotalocalcaneal arthrodesis procedures by two surgeons(ITS and NJT) using T2 Ankle nail fixation. 3 patients died of unrelated causes before follow up was complete which left 50 patients(52 nails); the largest consecutive series in the use of this device. Mean follow up was 23.5(3–72) months with the average age of patients being 61(range 22–89) years. An 84% response was achieved to a function and patient satisfaction questionnaire. Main indications for treatment were combined ankle and subtalar arthritis(63%-33/52) or complex hindfoot deformities(23%-12/52). Outcome was assessed by a combination of Clinical notes review, clinical examination, and telephone questionnaire.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 189 - 189
1 Sep 2012
Harding D Loesener G Ngyuen B Blackburn D Dixon R Taylor J
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Purpose

Total disc replacement (TDR) devices have been restricted to designs with large, congruent articulations due to the limited wear properties of available materials. TDRs with more natural motion could be designed if materials were available which could resist the higher wear conditions. A novel TriLobe TDR design is self-centering and energetically stable, emulating the natural motion of the intact motion segment, but is not feasible using traditional materials due to small incongruent articulating surfaces. The objective of this study was to compare the wear properties of a medical grade polycrystalline diamond with wear properties of cobalt chrome (CoCr) and ultrahigh molecular weight polyethylene (UHMWPE) in aggressive high wear conditions.

Methods

A modified pin-on-disc, crossing-path wear test was used to measure the wear rates of PCD-on-PCD, CoCr-on-CoCr, and CoCr-on-UHMWPE. The discs were placed in the inferior position on an oscillating plate, moving in a 10mm by 5mm figure-eight pattern. Pins had an initial 11.5mm radius and were loaded at 133N normal to the disc. In a typical pin-on-disc test, a wear flat develops on the pin and the wear rate is reduced as the contact area increases. The TriLobe design uses three lobes sliding in three non-conforming lenses which prevents wear flats from developing. To approximate this condition, the fixture holding the disc was placed on an air bearing and was allowed to rock in concert with movement of the load. The test was conducted in 25% bovine serum at a speed of less than two Hertz. Two sets of each material were tested, one set to 2.0 million cycles and the other set to 14.0 million cycles. Wear rates on the rocking-discs were measured using a high resolution coordinate measuring machine because the wear in the PCD specimens was not detectable gravimetrically.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XL | Pages 190 - 190
1 Sep 2012
Nguyen B Taylor J
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Purpopse

Few Cervical Total Disc Replacement (TDR) devices are engineered to address both the Center of Balance (COB) and the Center of Rotation (COR) of the cervical motion segments. The COB is the axis in the intervertebral disc through which the axial compressive load is transmitted. TDRs placed posterior of this point tend to fall into kyphosis while devices placed anterior of this point tend to fall into lordosis. Thus from a “balancing” point of view the ideal placement would be at the COB. However, the COR position has been shown to be posterior and inferior to the disc space. It has also been shown that constrained devices tend to lose motion when there is a mismatch between device and anatomic centers. Mobile core devices may be placed at the COB since their unconstrained rotations and translations allow for the device COR to follow the anatomic COR, but they rely heavily on the facet joints and other anatomic features to resist the paradoxiacal motion.

The TriLobe cervical TDR (Figure 2) was engineered for both the COB and COR. The purpose of this study was to compare the 3D kinematic and biomechanical performance of the TriLobe to a ball and trough(BT) cervical TDR in an augmented pure moment cadaveric study to find the ideal AP implant placement.

Materials and methods

Specimen were CT imaged for three-dimensional reconstruction. Visual, CT, and DEXA screening was utilized to verify that specimens are free from any defects. Specimens were prepared by resecting all nonligamentous soft tissue leaving the facet joint capsules and spinal ligaments intact. C2 and T1 were potted to facilitate mounting in the testing apparatus (7-axis Spine Tester, Univ. of Utah, Salt Lake City, UT). OptoTRAK motion tracking flags were attached to each vertebra including C2/C3 and T1 to track the 3D motion of each vertebra.

Specimens C2–T1.

Treatment Level C5–C6.

Insertion of fixture pins under fluoro.

Load Control Testing to 2.5Nm in FE, LB, AR at 0.5Hz.

15 Pre-cycles in load control in FE / LB / AR (2.5Nm).

Test implants in load control in FE / LB / AR to 2.5Nm for 4 cycles with data recorded for all cycles.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXII | Pages 9 - 9
1 Jul 2012
Guyver P Taylor J Knox R Czipri M Talbot N Sharpe I
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Tibiotalocalcaneal arthrodesis is an important salvage method for patients with complex hindfoot problems including combined arthritis of the ankle and subtalar joints, complex hindfoot deformities and failed total ankle arthroplasty. The aim of this study was to report the elective results of combined subtalar and ankle arthrodesis using one design of dynamic retrograde intramedullary compression nail-the T2 Ankle Arthrodesis Nail(Stryker)

Retrospective review identified 53 consecutive patients who had 55 tibiotalocalcaneal arthrodesis procedures by two surgeons(ITS and NJT) using T2 Ankle nail fixation. 3 patients died of unrelated causes before follow up was complete which left 50 patients(52 nails); the largest consecutive series in the use of this device. Mean follow up was 23.5(3-72) months with the average age of patients being 61(range 22-89) years. An 84% response was achieved to a function and patient satisfaction questionnaire. Main indications for treatment were combined ankle and subtalar arthritis(63%-33/52) or complex hindfoot deformities(23%-12/52). Outcome was assessed by a combination of Clinical notes review, clinical examination, and telephone questionnaire.

46 patients(83.6%) achieved union at a mean time of 3.7 months. 8 patients required an allograft(femoral head) bone block procedure. 4 patients(10%) subjectively thought that the procedure was of no benefit or had a poor result whilst 35(83%) had a good or excellent result. The mean visual analog scale(VAS) score for preoperative functional pain was 7.1 compared to the mean post operative (VAS) score of 1.9(p<0.001). Complications consisted of 2 amputations, 2 deep infections and 5 removals of broken or painful screws. The use of preoperative functional aids and orthotics dropped from 32% to 18% and 22% to 18% respectively.

This device and technique is a safe and effective treatment of hindfoot arthrosis and deformity giving reliable compression and subsequent fusion with excellent results in terms of patient satisfaction and pain relief.