Hydroxyapatite Coated External Fixation Pins

Caja, V. L.; Moroni, Antonio

doi:10.1097/00003086-199604000-00033

Cited by 63 publications

(41 citation statements)

References 3 publications

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“…Improvement of the purchase of HA-coated implants from implantation to extraction was first described in 1996 by Caja and Moroni in an experimental study of external fixation in sheep [1]. Similar results were also described in a clinical study by Magyar et al [9].…”

Section: Discussionsupporting

confidence: 60%

“…In a clinical study on hemicallotasis for osteoarthritis of the knee, coating of external fixation screws with plasma-sprayed HA gave a significantly better purchase for the screws, and prevented loosening of the screws in all cases but one [9]. In an experimental study on sheep, HA coating of loaded external fixation pins led to significantly lower radiographic pin tract rarefaction, better bone-implant contact based on histologic examination and greater force needed to remove the implants [1]. Coating of pedicular screws with plasma-sprayed HA has been used clinically [7], but the effects on radiolucent Abstract Loosening of the screws is a problem in instrumentation with pedicle screws.…”

Section: Introductionmentioning

confidence: 99%

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Improved extraction torque of hydroxyapatite-coated pedicle screws

Sandén¹,

Olerud²,

Johansson

et al. 2000

European Spine Journal

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Section: Discussionsupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Improved extraction torque of hydroxyapatite-coated pedicle screws

Sandén¹,

Olerud²,

Johansson

et al. 2000

European Spine Journal

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“…[9][10][11][12] However, these pins are usually only partially coated in the threaded region, which will be in contact with bone.…”

Section: Introductionmentioning

confidence: 99%

Modulation of the soft tissue reactions to percutaneous orthopaedic implants

et al. 2006

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To evaluate soft tissue reactions and biofilm formation on percutaneous external fixator screws coated with diamond-like carbon (DLC) and hydroxyapatite (HA) coatings on stainless-steel (SS) pins in an ovine loaded osteotomy model, an Orthofix external fixator was used to stabilize a 3-mm tibial midshaft osteotomy with six tapered pins inserted into the right tibia of 32 skeletally mature Friesland ewes. Animals were divided into four groups; SS, fully coated HA, DLC, and HA-coated threads. At 10 weeks, specimens were harvested and the pins were removed en bloc to examine the interfaces between the surface coatings and the tissues. Fully coated HA pins had a significantly higher percentage of dermal contact with the pin surface than HA-coated threads (p ¼ 0.028). The presence of a biofilm was evident on all pin surfaces except DLC-coated pins. Significantly greater numbers of bacteria were present on fully coated HA and plain stainless-steel pins compared with DLC. The surface of DLC-coated pins had a significantly lower number of bacterial colonies compared to SS (p ¼ 0.028) and fully coated HA pins (p ¼ 0.005). Fully coated HA pins have greater dermal attachment to the pin surface than the other pin coatings investigated. DLC-coated pins have the potential to prevent biofilm formation and bacterial colonization that may reduce infection and consequent pin loosening. An external fixator pin that is partially coated with HA to encourage bone and soft tissue integration and with DLC to reduce biofilm formation is advocated. ß

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“…In clinical practice, there is more probability of wires going loose, leading to loss of stiffness[17]. Half pins do not need tensioning and with decreasing incidence of infection with surgical care and hydroxy-apatite coating[18,19] stiffness of a pin based fixator would be expected to be maintained during clinical use.…”

Section: Discussionmentioning

confidence: 99%

Comparison of transverse wires and half pins in Taylor Spatial Frame: A biomechanical study

et al. 2010

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BackgroundThe aim of this study was to compare the stiffness characteristics of Taylor Spatial Frame (TSF) fixed with transverse wires and half pins.Design & MethodsExperiments were carried out at the biomechanics laboratory at Cardiff University. All mechanical testing was performed with a servo hydraulic test frame (MTS 858 Mini Bionix II(R), MTS Corp., Mineapolis, USA). Custom built mounts were used to attach the bone rigidly to the one end of machine and the TSF ring to the other. Rings were fixed with 1.8 mm transverse wires or hydroxy-apatite coated 6.5 mm half pins in 45degrees, 60degrees, 75degrees and 90degrees divergence angles. Bone was loaded with axial load to 400 N and torque to 20 Nm in an indestructible manner. Load/displacement curve data were analyzed for slope and axial and angular displacements.ResultsFor larger diameter rings (180 mm), for axial stiffness there was no statistically significant difference between the transverse wires (4 wires with 2 rings) and the half pins (2 pins with 1 ring) (p > 0.05). For 155 mm internal diameter rings, half pins provided statistically higher axial stiffness than transverse wires (p = 0.036). The half pins show significantly more torsion stiffness in both ring diameters (p < 0.05) in comparison to transverse wires. As in axial stiffness, small diameter rings show increased stiffness in torsion. There is increase in axial and torsion stiffness with the increase in the divergence angle between the wires or pins (p < 0.05).Conclusion & Clinical RelevanceHalf pins provide greater stiffness to TSF frames and allow for axial micro motion as well. This work provides a rationale for clinical decision making about the use of tensioned transverse wires in comparison to half pins in construction of a TSF frame

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Hydroxyapatite Coated External Fixation Pins

Cited by 63 publications

References 3 publications

Improved extraction torque of hydroxyapatite-coated pedicle screws

Improved extraction torque of hydroxyapatite-coated pedicle screws

Modulation of the soft tissue reactions to percutaneous orthopaedic implants

Comparison of transverse wires and half pins in Taylor Spatial Frame: A biomechanical study

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