Symposium: Papers Presented at the Annual Meetings of The Hip Society
This symposium is composed of selected papers delivered at the Fall 2011 Closed Meeting of The Hip Society in New Albany, OH, USA, and the Open Scientific Meeting of The Hip Society on Specialty Day at the 2012 Annual Meeting of the American Academy of Orthopaedic Surgeons in San Francisco, CA, USA. These meetings focused on current basic and clinical research related to novel biomaterials and alternative bearing surfaces, outcome studies on different surgical techniques and prosthesis designs for primary and revision hip arthroplasty, patient characteristics that may influence clinical outcome, and hip-preserving procedures.
Metal-on-metal (MOM) hip articulations continue to undergo close scrutiny. Indeed, a recent FDA panel meeting was held to discuss pertinent scientific and clinical aspects related to this articulation. The present Hip Society symposium highlights several important studies that address topics such as the interpretation of metal ion levels after MOM hip arthroplasty and outcome studies on MOM total and resurfacing hip arthroplasty. Whereas some MOM bearings appear to be functioning quite well, others have been withdrawn from the market. Ongoing clinical surveillance, including periodic analysis of metal ion levels and imaging studies using advanced metal suppression techniques, will shed more light on the future of this bearing couple.
Acetabular components containing crosslinked polyethylene (XLPE) continue to perform well in the intermediate term. Coupled with a metal or ceramic femoral head, XLPE now is the material of choice for the acetabular side. Larger femoral heads are being used with XLPE to obtain a more stable articulation, decreasing the dislocation rate substantially. Furthermore, patient activity appears to decrease with age, thus giving the possibility of increased longevity of currently implanted XLPE liners. However, overly thin polyethylene liners and suboptimal cup position are still discouraged because of the possibility of fracture of the plastic.
Which patient characteristics increase the complication rate after THA? Recent evidence implicates smoking and excessive alcohol use as potential risk factors for early failure. Dislocation is also increased in patients with neurologic disorders and in complex revision cases. So-called minimally invasive surgical approaches have also garnered much recent attention. However, it appears no one surgical approach leads to a better outcome in experienced hands.
Revision surgery on the femoral side often presents great challenges due to deficient bone stock and soft tissue compromise. Recent intermediate-term studies have shown modular tapered stems can have a satisfactory outcome in these difficult situations. Longer-term studies are needed to compare clinical outcomes with monoblock revision stems.
This symposium highlights some of the important basic and clinical research reported by members of The Hip Society and serves an educational purpose for surgeons undertaking surgical procedures of the hip. The studies reported in this symposium have all undergone rigorous peer review. The Hip Society is pleased to present this information to help improve patient outcomes and stimulate ongoing research in this area.