Effect of hydroxyapatite impregnation on skeletal bonding of porous coated implants

Intimate contact at the bone-porous surface interface is not always achievable in noncemented prosthetic implantation. We investigated the effect of hydroxyapatite (HA) coating on skeletal attachment in noninterference fit 4 weeks after implantation in 6 mature dogs. The pushout test of HA-coated implants surrounded by a 1-mm gap showed a twofold increased shear strength and fivefold increased shear stiffness compared with titanium alloy (Ti) coated implants. The fixation of Ti implants was reduced by two thirds when inserted in a gap as compared with press fit, whereas HA-coated implants in gap showed anchorage close to implants in press fit. Only minor differences were found between HA and Ti implants in press fit. Histomorphometric analysis showed a significant increase in bone in direct contact to HA-coated implant as compared with Ti implants inserted both in gap and press fit. The study indicates that tightness of surgical fit is an important factor for sufficient fixation of the implant. However, our results demonstrate that hydroxyapatite coating almost eliminates the negative influence of noninterference fit between bone and unloaded implant.The quantity of bone ingrowth into porous-coated implants depends, among other factors, on the interference fit obtained with the surrounding bone (Albrektsson and Albrektsson 1987, Cameron et al. 1976, Carlsson et al. 1988a, Harris et al. 1983, Sandborn et al. 1988). In the clinical situation, however, direct apposition of implant to bone is not always achievable Engh 1984, Engh et al. 1987 Schimmel and Huiskes 1988). Lack of optimal flatness after bone cutting, implant design deficiencies, and anatomic variations may result in gaps between the implant surface and surrounding bone Albrektsson 1987, Larsen andRyd 1990).Calcium phosphates in the form of granules have been employed to fill in gaps between bone and implant with no demonstrable effect on bone ingrowth at early time periods (Eschenroeder et al. 1987, Russotti et al. 1986. Recently, deposition of dense hydroxyapatite (HA) on titanium alloy (Ti) by plasma spraying technique has been shown to improve the HA-metal substrate interface shear strength , Thomas et al. 1987. HA coating provides earlier bone ingrowth compared with Ti (Geesink et al. 1988, Saballe et al. 1989a, b, c, Thomas et al. 1987.We examined the effect of HA coating on skeletal attachment of unloaded porous titanium implants inserted in noninterference fit compared with press fit insertion. Material and methodsExperimental design. Six skeletally mature labrador dogs of both sexes weighing 28 (22-31) kg comprised the material. Ti-and HA-coated implants were inserted in press fit or in noninterference fit in the distal femoral condyles. The dogs were killed after 4 weeks and the results were evaluated by the mechanical push-out test and histomorphometric analysis.Bone-density measurements. To investigate bone density at implantation site, CT scanning of the distal femora was performed 1 week before surgery as previously described (Saballe ...

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“…Ducheyne et al (1980) found a far greater amount of bony ingrowth after 2 and 4 weeks with the HA-impregnated samples.…”

Section: Discussionmentioning

confidence: 75%

Hydroxyapatite coating enhances fixation of porous coated implants: A comparison in dogs between press fit and noninterference fit

Søballe¹,

Hansen²,

Brockstedt-Rasmussen

et al. 1990

Acta Orthopaedica Scandinavica

185

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“…Some have reported that there is no clinical advantage 14 while others have demonstrated a significant increase in bone ingrowth. 15,16 We have investigated bone ingrowth and attachment to an HA-coated porous titanium surface, a plain porous titanium surface and a roughened titanium (Interlok) surface finish in one femoral design from specimens obtained at post-mortem.…”

mentioning

confidence: 99%

A comparison of bone remodelling around hydroxyapatite-coated, porous-coated and grit-blasted hip replacements retrieved at post-mortem

Coathup¹,

Blunn²,

Flynn³

et al. 2001

The Journal of Bone and Joint Surgery. British volume

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W e investigated the implant-bone interface around one design of femoral stem, proximally coated with either a plasma-sprayed porous coating (plain porous) or a hydroxyapatite porous coating (porous HA), or which had been grit-blasted (Interlok). Of 165 patients implanted with a Bimetric hip hemiarthroplasty (Biomet, Bridgend, UK) specimens were retrieved from 58 at post-mortem.We estimated ingrowth and attachment of bone to the surface of the implant in 21 of these, eight plain porous, seven porous HA and six Interlok, using image analysis and light morphometric techniques. The amount of HA coating was also quantified.There was significantly more ingrowth (p = 0.012) and attachment of bone (p < 0.05) to the porous HA surface (mean bone ingrowth 29.093 ± 2.019%; mean bone attachment 37.287 ± 2.489%) than to the plain porous surface (mean bone ingrowth 21.762 ± 2.068%; mean bone attachment 18.9411 ± 1.971%). There was no significant difference in attachment between the plain porous and Interlok surfaces. Bone grew more evenly over the surface of the HA coating whereas on the porous surface, bone ingrowth and attachment occurred more on the distal and medial parts of the coated surface. No significant differences in the volume of HA were found with the passage of time.This study shows that HA coating increases the amount of ingrowth and attachment of bone and leads to a more even distribution of bone over the surface of the implant. This may have implications in reducing stress shielding and limiting osteolysis induced by wear particles. The use of hydroxyapatite (HA) coating has been advocated in order to increase the attachment of bone to metal implants. Many animal as well as clinical studies have demonstrated the osseoconductive properties of HA and the results at six to eight years are excellent.1,2 Bone apposition appears to be well advanced as early as three weeks, 3 and some studies have shown it to be greater than 90% at 96 weeks. 4 Although there is concern that HA resorbs with time and that the release of HA debris may have adverse effects, 5 the clinical results reported so far for HA-coated components suggest that at present this is not a significant problem. Several reports of the outcome after the insertion of porous-coated uncemented implants have shown good results.6-8 Most studies found some degree of bone ingrowth into the pores 9-12 with the mean extent reported to be in the range of 5% 9,12 to 39.2% 13 of the available pore volume. An HA coating has been advocated in order to reduce the effects of debonding and to encourage bone ingrowth and attachment to a porous surface. Several studies have examined the use of an HA surface coating on porous-coated implants. Some have reported that there is no clinical advantage 14 while others have demonstrated a significant increase in bone ingrowth. 15,16 We have investigated bone ingrowth and attachment to an HA-coated porous titanium surface, a plain porous titanium surface and a roughened titanium (Interlok) surface finish in one femoral design from s...

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“…Many researchers later on discovered some other ceramics, glass-ceramics and composites also have the same property (De Groot, 1983De Groot et al, 1990;De Groot & LeGeros, 1988;Ducheyne et al, 1980;Gross et al, 1988;Gross and Strunz, 1985;Hench, 1987Hench, , 1988Hench & Ethridge, 1982;Hench et al, 1971;Hench & Wilson, 1984;Holand et al, 1985;Hulbert et al, 1987;Jarcho, 1981;Kitsugi et al, 1989;Kokubo et al, 1986;Kokubo et al, 1982;Nakamura et al, 1985;Wilson et al, 1981;Yamamuro et al, 1990b;Yamamuro et al, 1988;Yoshii et al, 1988). He defined these glasses as 'bioactive glass' and since then it has been used mostly as a reconstructive material for damaged hard tissues such as bone (Hench, 2006;Hench et al, 1971).…”

Section: Bioactive Glass Materialsmentioning

confidence: 99%

Development and Applications of Varieties of Bioactive Glass Compositions in Dental Surgery, Third Generation Tissue Engineering, Orthopaedic Surgery and as Drug Delivery System

Nandi¹,

Kundu²,

Datta³

2011

Biomaterials Applications for Nanomedicine

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Effect of hydroxyapatite impregnation on skeletal bonding of porous coated implants

Cited by 326 publications

References 9 publications

Hydroxyapatite coating enhances fixation of porous coated implants: A comparison in dogs between press fit and noninterference fit

Hydroxyapatite coating enhances fixation of porous coated implants: A comparison in dogs between press fit and noninterference fit

A comparison of bone remodelling around hydroxyapatite-coated, porous-coated and grit-blasted hip replacements retrieved at post-mortem

Development and Applications of Varieties of Bioactive Glass Compositions in Dental Surgery, Third Generation Tissue Engineering, Orthopaedic Surgery and as Drug Delivery System

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