Failure of dual radius hydroxyapatite-coated acetabular cups

<p>Abstract</p> <p>Introduction</p> <p>Many kind of hydroxyapatite-coated cups were used, with favorable results in short term studies; it was supposed that its use could improve osteointegration of the cup, enhancing thus stability and survivorship. The purpose of this study is to analyze the long term behavior of the hemispheric HA coated, Dual Radius Osteonics cup and to discuss the way of failure through the exam of the revised components and of both periacetabular and osteolysis tissue.</p> <p>Materials and Methods</p> <p>Between 1994 and 1997, at the Department of Orthopedic Sciences of the Insubria University, using the posterolateral approach, were implanted 276 Dual Radius Osteonics^®in 256 patients, with mean age of 63 years.</p> <p>Results</p> <p>At a mean follow-up of 10 years (range 8–12 years), 183 cups in 165 patients, were available for clinical and radiographical evaluation. 22 Cups among the 183 were revised (11%). The cause of revision was aseptic loosening in 17 cases, septic loosening in one case, periprosthetic fracture in another case, osteolysis and polyethylene wear in two cases and, finally, recurrent dislocations in the last one. In the remaining patients, mean HHS increased from a preoperative value of 50,15 to a postoperative value of 92,69. The mean polyethylene wear was 1,25 mm (min. 0,08, max. 3,9 mm), with a mean annual wear of 0,17 mm. The mean acetabular migration on the two axis was 1,6 mm and 1,8 mm. Peri-acetabular osteolysis were recorded in 89% of the implants (163 cases). The cumulative survivorship (revision as endpoint) at the time was 88,9%.</p> <p>Conclusion</p> <p>Our study confirms the bad behavior of this type of cup probably related to the design, to the method of HA fixation. The observations carried out on the revised cup confirm these hypotheses but did not clarify if the third body wear could be a further problem. Another interesting aspect is the high incidence of osteolysis, which are often asymptomatic becoming a problem for the surgeon as the patient refuses the possibility of a revision.</p

The beneficial effect of hydroxyapatite lasts: A randomized radiostereometric trial comparing hydroxyapatite-coated, uncoated, and cemented tibial components for up to 16 years

Analysis and Stochastic

Assessment of bone ingrowth potential of biomimetic hydroxyapatite and brushite coated porous E-beam structures

The bone ingrowth potential of biomimetic hydroxyapatite and brushite coatings applied on porous E-beam structure was examined in goats and compared to a similar uncoated porous structure and a conventional titanium plasma spray coating. Specimens were implanted in the iliac crest of goats for a period of 3 (4 goats) or 15 weeks (8 goats). Mechanical implant fixation generated by bone ingrowth was analyzed by a push out test. Histomorphometry was performed to assess the bone ingrowth depth and bone implant contact. The uncoated and hydroxyapatite-coated cubic structure had significantly higher mechanical strength at the interface compared to the Ti plasma spray coating at 15 weeks of implantation. Bone ingrowth depth was significantly larger for the hydroxyapatite- and brushite-coated structures compared to the uncoated structure. In conclusion, the porous E-beam surface structure showed higher bone ingrowth potential compared to a conventional implant surface after 15 weeks of implantation. Addition of a calcium phosphate coating to the E-beam structure enhanced bone ingrowth significantly. Furthermore, the calcium phosphate coating appears to work as an accelerator for bone ingrowth

Use and efficacy of bone morphogenetic proteins in fracture healing

Signal transduction in aging related disease

Three-dimensional analytical techniques for evaluation of osseointegrated titanium implants

Osseointegration, the direct bonding of titanium implant materials with bone, is critical for implant success where nanostructured surface features contribute to nano-osseointegration. However, we also know that features and processes on the microscale influence the biocompatibility of implant materials. We highlight the advantages of using mutlilength scale analyses, focusing on three-dimensional techniques, ranging from X-ray microcomputed tomography, to focused ion beam, to high resolution electron tomography to identify markers of osseointegration. A titanium implant with modified biomimetic coating studied in vitro and in vivo at various time points is used to exemplify the complementary information gained from three-dimensional analyses from the micro- to nanoscale