Samo K Fokter
University Medical Center Maribor, Slovenia
Title: The innovation trap: A nation-wide problem of modularity in primary total hip arthroplasty
Biography
Biography: Samo K Fokter
Abstract
Statement of the Problem: Innovations play the key role in the success of orthopedic surgery. However, even minor modifications in the established concepts and proven designs may result in disasters. The endemic of modular femoral neck fracture (23 cases) in fully modular total hip arthroplasty, popular in Central Europe for the last 15 years, seems to challenge us with such an unfortunate consequences.
Methodology & Theoretical Orientation: Literature search for problems associated with Profemur Z (MicroPort Orthopedics Inc., Arlington, TN, USA) fully-modular femoral stem made of titanium alloy (Ti6Al4V) was performed and hip arthroplasty registries were searched to evaluate the failure rates of this specific stem design. Mechanisms of failure were studied to get in-depth understanding of this particular hip reconstruction device.
Findings: Since 2010 onwards, several case reports on catastrophic modular femoral neck fractures of Profemur Z were published. The first Slovenian case was described in 2012. Two small series of patients with sudden modular femoral neck fractures were published in 2016. The Australian Joint Replacement Registry was the first to discover increased revision rates due to fractures of this hip reconstruction system. Corrosion at the neck-taper interface, where two equal or different materials are subject to constant wear in the presence of body fluids, is assumed to be responsible for the unacceptable high failure rate.
Conclusion & Significance: Manufacturers are responsible to produce and market only safe devices. However, orthopedic surgeons should carefully monitor any adverse effect of innovations. As late as in 2015, an urgent field safety corrective notice was sent from the manufacturer indicating that all lots of long modular necks made from cobalt-chromium alloy should be withdrawn. A national arthroplasty registry would probably warn orthopedic community on this questionable innovation earlier.