Local bisphosphonate treatment increases fixation of hydroxyapatite‐coated implants inserted with bone compaction

Abstract

It has been shown that fixation of primary cementless joint replacement can independently be enhanced by either: (1) use of hydroxyapatite (HA) coated implants, (2) compaction of the peri-implant bone, or (3) local application of bisphosphonate. We investigated whether the combined effect ofHAcoating and bone compaction can be further enhanced with the use of local bisphosphonate treatment .HA-coated implants were bilaterally inserted into the proximal tibiae of 10 dogs. On one side local bisphosphonate was applied prior to bone compaction. Saline was used as control on the contralateral side. Implants were evaluated with histomorphometry and biomechanical pushout test. We found that bisphosphonate increased the peri-implant bone volume fraction (1.3-fold), maximum shear strength (2.1-fold), and maximum shear stiffness (2.7-fold). No significant difference was found in bone-to-implant contact or total energy absorption. This study indicates that local alendronate treatment can further improve the fixation of porous-coated implants that have also undergone HA-surface coating and peri-implant bone compaction.

The Effect of Soaking Allograft in Bisphosphonate: A Pilot Dose-response Study

“…We observed an enhancing effect on new bone formation with our low dose of zoledronate but an inhibitory effect with our high dose of zoledronate. This is in accordance with other studies in which an increase in biomechanical fixation correlated to an increase in amount of bone [7,15,16]. However, an increase in bone volume fraction resulting from preservation of allograft with a high dose of zoledronate did not correlate with an increase in biomechanical fixation.…”

“…One explanation for this augmenting effect could be the preserving effect of zoledronate on the allograft, thus prolonging its osteoconductive effect and thereby increasing new bone formation. This has been observed in other studies [2,3,15,16]. The amount of new bone in the low-dose group was similar in magnitude as reported by others [3].…”

Bisphosphonate Remains Highly Localized After Elution From Porous Implants

“…Once released from the implant and bound to the mineral phase of bone, the bisphosphonate interferes with osteoclast metabolism and suppresses resorption, thereby tipping the balance of bone turnover in favor of a net gain in bone formation [6,22]. This has been reproducibly demonstrated in studies using alendronate [3,8,12], clodronate [11], ibandronate [10], and zoledronic acid [5,7,20,21,[25][26][27], the most potent and long-lasting bisphosphonate and one of several thirdgeneration compounds being used clinically to mitigate the effects of osteoporosis [4,16]. The effect of local zoledronic acid elution on net local bone formation around animal implants can be quite striking, with increases in bone ingrowth, bone apposition, and periimplant bone ranging from 60% to 130% within 12 weeks of surgery and persisting out to 1 year postoperatively [5,27].…”

Effects of local alendronate administration on bone defect healing. Histomorphometric and radiological evaluation in a rabbit model

“…In their study on tibial implants, Jakobsen et al 20,21 used alendronate solution with local administration, and determined the optimal concentration to be 2 mg/mL. For the repair of skull defects in rats, Toker et al 19 used alendronate solution at the concentration of 1 mg/mL.…”