Bone remodelling around HA-coated acetabular cups

Abstract

This study was designed to investigate bone remodelling around the cup in cementless THA. Previous studies indicate an advantage of better sealing of the bone-prosthesis interface by HA/TCP coating of implants, inhibiting polyethylene-induced osteolysis. One hundred patients gave informed consent to participate in a controlled randomized study between porous coated Trilogy versus Trilogy Calcicoat (HA/TCP coated). The cup was inserted in press-fit fixation. The femoral component was a cementless porous coated titanium alloy stem (Bi-Metric), with a modular 28-mm CrCo head. The Harris Hip Score (HHS) and bone mineral density (BMD) determined by DEXA scanning were used to study the effect. Measurements revealed no difference between the two groups after 3 years either in the clinical outcome or in terms of periprosthetic bone density. Patients with a body mass index above normal regained more bone mineral than patients with normal weight. This finding supports the assumption that load is beneficial to bone remodelling.

Experimental validation of numerically predicted strain and micromotion in intact and implanted composite hemi-pelvises

“…It is therefore evident from the study that implantation causes localised increases in strains in a few locations around the acetabulum. These changes in load transfer mechanism after implantation are corroborated by published data [43][44][45][46]. In the clinical study by Wright et al [43], periacetabular bone-mineral density was assessed in a group of twenty-six patients who underwent primary total hip arthroplasty using press-fit acetabular cups.…”

“…The compressive and tensile strains in rosettes 4 and 5 increased considerably after implantation, indicating high load transfer through the cortical shell on the rear surface of the acetabulum. However, a reduction in compressive strains for rosettes 1 and 2 was evident, which may not be entirely consistent with increased cortical load transfer observed clinically [43,44]. In the proximal ilium, a reduction in the tensile and compressive strains was observed in the rosette 3, indicating possible strain shielding.…”

Experimental Validation of Finite Element Models of Intact and Implanted Composite Hemipelvises Using Digital Image Correlation

“…A clinical bone remodelling study around cementless acetabular components by Meneghini et al [40] observed that relative bone density was increased in the periphery of the acetabulum, due to increased load transfer through that region. Laursen et al [39] reported bone mineral density changes that stabilised over the first postoperative year, which is consistent with an adaptive bone remodelling process. Similar results were reported by Manley et al [43], who observed using FE analysis that the implanted pelvis had less load transfer in the anterior and posterior regions of the acetabulum, and adjacent to the ischial facet as compared to the normal hip.…”

Periacetabular Bone Mineral Density Changes After Resurfacing Hip Arthroplasty Versus Conventional Total Hip Arthroplasty. A Randomized Controlled DEXA Study

“…In clinical [12,23,24] and finite element [10,25] studies a 5% to 50% decrease was found in the ROI medial to the acetabular cup. The BMD preservation of RHA patients was most profound cranial to the cup (ROIs 1 and 5) for RHA patients.…”

“…Finite element analyses predict medial bone loss up to 50% caused by stress shielding, and a bone gain near the prosthetic rim of press-fit cups (which is the main loading site of the pelvis) [10]. Clinical DEXA studies on metal-on-poly (MoP) conventional THA confirm these results [11,12]. Little is known about periprosthetic acetabular BMD changes around MoM implants and resurfacing hip arthroplasty (RHA) in particular.…”