Current methods of preventing aseptic loosening and improving osseointegration of titanium implants in cementless total hip arthroplasty: a review

Abstract

Hip osteoarthritis is the most common joint disorder, and is represented by a degenerative process, resulting in pain and functional impairment. If conservative treatment for hip osteoarthritis fails, the only remaining option is hip arthroplasty. Despite good survival of implants, loosening of components is the most common complication. This leads to revision surgeries, which are technically demanding, expensive, and result in a low satisfaction rate. Uncemented hip replacements require proper osseointegration for increased survival. Physical characteristics of implants include biocompatibility, Young's modulus of elasticity, strength, and corrosion resistance, and each influence fixation of implants. Moreover, implant surface treatments, pore size, pore density, and femoral stem design should be appropriately selected. Patients' optimization of obesity, osteoporosis, cardiovascular disease, psychotic disorders, and smoking cessation are associated with a higher survival of implants. Surgical factors, such as approach, drilling and rasping, acetabular bone coverage, acetabular cup positioning, and implant size, also affect survival of implants. Avoiding drugs, which may impair osseointegration of implants, and having an appropriate rehabilitation protocol are important. Future directions include anabolic and anti-catabolic bone-acting drugs to enhance osseointegration of implants. Comprehensive knowledge of the factors mentioned above is important for preventing aseptic loosening, with important socioeconomic consequences.

Keywords: Osseointegration; aseptic loosening; cementless hip arthroplasty; osteoarthritis; surgery; titanium implant.

Figure 1.

Radiolucency zones greater than 2 mm (black arrows) at the femoral stem showing aseptic loosening

Figure 2.

Scanning electron microscopy images of titanium implants seeded with osteoblasts cells (a) Ti6Al7Nb implants as a control (TiCtrl) seeded with osteoblast cells (arrow shows cells surrounded by bone matrix). (b) Titanium implants coated with hydroxyapatite (TiHA) and seeded with osteoblast cells (arrow shows a strong matrix deposition with cells surrounded by bone matrix). (c) Titanium implants with bioactive silicatitanate coating (TiSiO₂) seeded with osteoblast cells (arrow shows a large flattened cell with numerous extensions) (magnification, ×3000).

Figure 3.

Scanning electron microscopy images of titanium implants seeded with dental follicle stem cells Left panel: untreated titanium implant (TiCtrl), hydroxyapatite-coated titanium implant (TiHA), and silicatitanate-coated titanium implant (TiSiO₂) without cells. Right panel: TiCtrl, TiHA, and TiSiO₂ implants with dental follicle stem cells after 21 days of cell culture (magnification, ×500).

Figure 4.

In vitro release of metal ions from a titanium implant