A Multi-centre, Prospective, Clinical Outcomes Study to evaluate the MPRES Stem following primary Total Hip Arthroplasty

Traditionally, surgeons undertaking THA have performed a distal neck osteotomy, which invariably necessitated the excision of healthy bone. The introduction of bone-conserving short-stem implants has shown there is a growing body of evidence to suggest that retaining the femoral neck can provide mechanical and biological advantages. One of the aims of successful THA is to restore this environment to its native state. Following surgery, femoral components are subject to high torsional and shear forces that can precipitate implant movement. Torsional stability is known to be an important factor in implant fixation and can influence survivorship. The prostheses are also subjected to vertical forces that can produce interface micro-motion or result in migration of the stem into varus. It is argued that neck preservation offers superior tri-planar implant stability and allows more accurate restoration of the hip biomechanics. Medacta International have recently developed a new short femoral stem device designed for use in total hip arthroplasty. The femoral stem is one component of a total hip replacement. The MPRES femoral stem is not yet approved by the TGA however, Medacta International has obtained European CE Mark Approval. CE Marking allows Medacta to supply the MPRES device in the European Union (EU). The MPRES is a Neck Sparing Stem, as it is designed to be bone conserving. It has been designed as a primary uncemented femoral stem for use in total hip arthroplasty. The design intent on the MPRES stem is to provide a THA that preserves healthy bone stock and allow for minimal invasive surgical approaches. The MPRES is a cementless, biplanar, wedge-shaped monoblock stem of Titanium Alloy and hydroxyapatite coating. It is currently unknown if the new MPRES cementless femoral stem device has noninferiority revision rates in comparison to all other on-market femoral stems. The purpose of this study is to assess the safety and performance of the MPRES. This will be achieved by both assessing the survivorship data and collecting patient reported outcome measures from patients who are having the MPRES device.