Alternative Bearing Designs for Hip Resurfacing Arthroplasty

Abstract

Hip resurfacing is used as an alternative option for young patients suffering from osteoarthritis. Standard implants used for resurfacing have similar designs and biomechanical properties. We present a hip resurfacing system that restores the surface with minimal bone loss and preserves the subchondral bone stock of the femoral head by reaming the surface only without any bone resection and insertion of an onlay femoral cap. This technique is performed without guide pins or the need of navigation. No stem is used in the onlay resurfacing technique. The surface of the femoral component was designed using a biosurf structure, which achieved 14% less wear by reducing metal debris and increasing lubrication because of the biosurf-structured surface. The acetabular component is a modular system, which allows easier revision if required. Low viscosity cement is used for fixation of the femoral component. A cementless acetabular cup with trabecular metal structured surface is used, which is made of titanium-niobium, hydroxylapatit coated. A highly polished insert is placed into the cementless fixated socket. We also describe a modified minimally invasive anterolateral approach with complete prevention of any muscle resection. FIGURE 3. Femoral head after reaming.FIGURE 4. Surface of the femoral component with defined dimples.www.techortho.com | 69 FIGURE 9. Femoral preparation and reaming profiles for traditional resurfacing (left) and onlay resurfacing (right).

Towards the First Generation of Biomimetic Fixation for Resurfacing Arthroplasty Endoprostheses

“…The first was a metal-on-metal ESKA-BIONIK ® hip resurfacing system (also known as Biosurf ® hip resurfacing), which has a unique bearing surface hydrodynamic lubrication in the bearings through the concavo-convex pattern designed to reduce abrasive wear. The pattern provided circumferentially distributed escape dimples for wear particles and improved lubrication by providing room for the lubricant [111]. The acetabular component had a spongiosa metal structured surface called Spongiosa Metal ® made of a CoCrMo with a titanium niobium (TiNb) coating or an HA coating, available upon request, for cementless anchorage through osseous integration that proved to have excellent long stability in clinical trials [96,97].…”

Failure Mechanisms in Hip Resurfacing Arthroplasty

“…This has also led to many different surgical approaches being tried by many surgeons in the past decade. [29] The posterior, poster-lateral [30], direct lateral, Ganz trochanteric flip [31], direct anterior [32], and antero-lateral [33] approaches. [34] Some complications of resurfacings shown in Fig 1A -1C.…”