The effect on implant fixation of soaking tricalcium phosphate granules in bisphosphonate

Synergistic use of biomaterials and licensed therapeutics to manipulate bone remodelling and promote non-union fracture repair

Disrupted bone metabolism can lead to delayed fracture healing or non-union, often requiring intervention to correct. Although the current clinical gold standard bone graft implants and commercial bone graft substitutes are effective, they possess inherent drawbacks and are limited in their therapeutic capacity for delayed union and non-union repair. Research into advanced biomaterials and therapeutic biomolecules has shown great potential for driving bone regeneration, although few have achieved commercial success or clinical translation. There are a number of therapeutics, which influence bone remodelling, currently licensed for clinical use. Providing an alternative local delivery context for these therapies, can enhance their efficacy and is an emerging trend in bone regenerative therapeutic strategies. This review aims to provide an overview of how biomaterial design has advanced from currently available commercial bone graft substitutes to accommodate previously licensed therapeutics that target local bone restoration and healing in a synergistic manner, and the challenges faced in progressing this research towards clinical reality.

Anabolic and antiresorptive actions of locally delivered bisphosphonates for bone repair: A review

During the last decades, several research groups have used bisphosphonates for local application to counteract secondary bone resorption after bone grafting, to improve implant fixation or to control bone resorption caused by bone morphogenetic proteins (BMPs). We focused on zoledronate (a bisphosphonate) due to its greater antiresorptive potential over other bisphosphonates. Recently, it has become obvious that the carrier is of importance to modulate the concentration and elution profile of the zoledronic acid locally. Incorporating one fifth of the recommended systemic dose of zoledronate with different apatite matrices and types of bone defects has been shown to enhance bone regeneration significantly in vivo. We expect the local delivery of zoledronate to overcome the limitations and side effects associated with systemic usage; however, we need to know more about the bioavailability and the biological effects. The local use of BMP-2 and zoledronate as a combination has a proven additional effect on bone regeneration. This review focuses primarily on the local use of zoledronate alone, or in combination with bone anabolic factors, in various preclinical models mimicking different orthopaedic conditions.

Cite this article: I. Qayoom, D. B. Raina, A. Širka, Š. Tarasevičius, M. Tägil, A. Kumar, L. Lidgren. Anabolic and antiresorptive actions of locally delivered bisphosphonates for bone repair: A review. Bone Joint Res 2018;7:548–560. DOI: 10.1302/2046-3758.710.BJR-2018-0015.R2.

Alendronate release from calcium phosphate cement for bone regeneration in osteoporotic conditions

Osteoporosis represents a major health problem in terms of compromising bone strength and increasing the risk of bone fractures. It can be medically treated with bisphosphonates, which act systemically upon oral or venous administration. Further, bone regenerative treatments in osteoporotic conditions present a challenge. Here, we focused on the development of a synthetic bone substitute material with local diminishing effects on osteoporosis. Composites were created using calcium phosphate cement (CPC; 60 wt%) and polylactic-co-glycolic acid (PLGA; 40 wt%), which were loaded with alendronate (ALN). In vitro results showed that ALN-loaded CPC/PLGA composites presented clinically suitable properties, including setting times, appropriate compressive strength, and controlled release of ALN, the latter being dependent on composite degradation. Using a rat femoral condyle bone defect model in osteoporotic animals, ALN-loaded CPC/PLGA composites demonstrated stimulatory effects on bone formation both within and outside the defect region.

Effect of local zoledronate delivery on osseointegration: a systematic review of preclinical studies

PURPOSE

The aim of the present systematic review was to assess the effect of local zoledronate (ZOL) delivery (topical or as implant surface coatings) on osseointegration.

MATERIALS AND METHODS

In this systematic review, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. To address the focused question, 'Does local zoledronate delivery enhance osseointegration?' indexed databases were searched without time or language restrictions up to and including April 2017 using various combination of the following keywords: 'zoledronate', 'bisphosphonates', 'osseointegration' and 'topical administration'. Letters to the Editor, historic reviews, commentaries, case-series and case-reports were excluded.

RESULTS

Initially, 383 articles were identified out of which, 23 experimental studies fulfilled the inclusion criteria. In 18 studies, ZOL was incorporated into implants surfaces as a coating and in five studies ZOL was applied topically (bone graft or irrigation) into the bone cavities. Results from 87% studies reported that local delivery of ZOL (coating or topical) is effective in enhancing osseointegration or new bone formation around implants.

CONCLUSIONS

Local ZOL delivery (coating or topical) seems to enhance osseointegration in animals; however, from a clinical perspective, further randomized control trials with long-term follow-up are needed in this regard.

Does Local Ibandronate and/or Pamidronate Delivery Enhance Osseointegration? A Systematic Review

PURPOSE

To our knowledge from indexed literature, the present study is the first one to systematically review the influence of local delivery of pamidronate (PAM) and/or ibandronate (IBA) on osseointegration enhancement. The aim of the present systematic review was to assess the efficacy of IBA and/or PAM local delivery (topically or coating on implants surfaces) in promoting osseointegration.

MATERIALS AND METHODS

To address the focused question, "Does local IBA and/or PAM delivery enhances osseointegration?," indexed databases were searched without time or language restrictions up to and including May 2016 using various combinations of the following keywords: "pamidronate," "ibandronate," "bisphosphonates," "osseointegration," and "topical administration." Letters to the Editor, historic reviews, commentaries, case series, and case reports were excluded.

RESULTS

Fifteen studies were included. Fourteen studies were performed in animals and 2 were clinical trials. One study reported an experimental model and a clinical trial in the same publication. Results from 12 experimental studies and 2 clinical studies reported improved biomechanical properties and/or osseointegration around implants with PAM and/or IBA. Two experimental studies showed that PAM and/or IBA did not improve osseointegration.

CONCLUSIONS

On experimental grounds, local IBA and/or PAM delivery seems to enhance osseointegration; however, from a clinical perspective, further randomized control trials are needed to assess the effectiveness of IBA and PAM in promoting osseointegration around dental implants.