Bone Remodeling and Hydroxyapatite Resorption in Coated Primary Hip Prostheses

Abstract

Hydroxyapatite coatings for THA promote bone ongrowth, but bone and coating are exposed to stress shielding-driven osteoclastic resorption. We asked: (1) if the resorption of hydroxyapatite coating and bone ongrowth correlated with demographics; (2) if the resorption related to the stem level; and (3) what happens to the implant-bone interface when all hydroxyapatite coating is resorbed? We recovered 13 femoral components from cadaveric specimens 3.3 to 11.2 years after uneventful primary THA. Three cross sections (proximal, medial, distal) of the hydroxyapatite-coated proximal implant sleeve were analyzed by measuring the percentage of residual hydroxyapatite and bone ongrowth on the implant perimeter. Hydroxyapatite resorption was independent of patient age but increased with time in vivo and mostly was gone after 8 years. Bone ongrowth was independent of time in vivo but decreased with aging patients. Only in the most proximal section did less residual hydroxyapatite correlate with less bone ongrowth. Hydroxyapatite resorption, which was more proximal than distal, showed no adverse effects on the implant-bone interface.

The Bicontact cementless primary total hip arthroplasty: long-term results

“…The effect usually manifests within the first six months after implantation. Proximal coating is thought to decrease the incidence of this resorption as is usually seen at the transition of the coated and uncoated portions of the stem [21]. This resorption was seen in 6% of our hips at long term as compared to 3% documented in the medium term.…”

“…It seems likely that little hydroxyapatite remains after ten years [21]. Contrary to published series reporting deteriorating results of uncemented stems with time from implantation [22], the uncemented Bicontact stem maintains its 100% survivorship.…”

“…A number of studies have reported the resorption of bone proximally. This is thought to result from stress shielding and is more documented with the use of porous-coated stems [21]. The effect usually manifests within the first six months after implantation.…”

Hydroxyapatite-lignin composite as a metallic implant-bone tissue osseointegration improver: experimental study in dogs

“…One strategy is coating metal implants with hydroxyapatite that produces stable fixation in hybrid prostheses in arthroplasty (PEREIRA et al, 2007). Moreover, the attachment promoted by hydroxyapatite is durable due to bone formation where the ceramic is absorbed (TONINO et al, 2009). Unlike hydroxyapatite-coated implants used in arthroplasty, the present study proposes a biomaterial that can fill the spaces between bone and implant at the moment of the surgery.…”

The Cementless Anatomic Benoist Girard (ABG) II Total Hip Arthroplasty

“…The occurrence of early high polyethylene wear has been attributed by several studies to a poor locking mechanism of the inserts, a metalback socket with 12 holes, and sterilization performed in air [1,3,5]. Also, bone remodelling in the form of proximal femoral bone resorption starting from the first postoperative year up to 10-year follow-up has been described in association with the ABG I femoral component [24][25][26][27]. These observations have led to the development of the ABG II prosthesis.…”