By: 22 January 2020
Onset of a minimally invasive era to set new possibilities for the bone cement industry

Alice Ajit Mutum, of Future Market Insights, looks at the rapidly evolving products and technologies in the bone cement industry

The emergence of personalised medicine and penetration of many technologies are adding to the uncertainty of global health economy – thereby compelling healthcare organizations to plan their future moves. The products and technologies surrounding orthopaedic implants in particular are rapidly evolving. Digital revolution is taking hold in line with surgeons benefiting from the incorporation of robotic-guidance systems. Additionally, orthopaedic surgery is on a path towards minimally invasive and highly precise operations, with a greater proportion of outpatient procedures. Today, as accuracy and comparable approaches take the front seat in assessment of the quality of care and outcomes, new tools and techniques are entering the field of orthopaedics.

The technology underlying long-term stability of fixation in bone achieved with cemented anchorage has matured significantly since its first usage in the 1940s, which was to close gaps in the human skull. Today, key advantages of bone cemented prosthesis depend on the optimal primary fixation between bone and implant, and subsequently in a faster patient recuperation. Well adapted to bone complex cavities, bone cement had long been a gold standard in the field of joint replacement. However, several shortcomings such as long-term prosthesis loosening and the potential breakdown of cement, side effects, and toxicity of bone cement are being effectively addressed recently. Moreover, the use of bone cement is marginally reduced with the advent of cementless or press-fit implant that encourages the natural bone to grow onto it.

The quest for promising material for bone cement remains strong

Bone cement based on polymethyl methacrylate (PMMA), also known as acrylic bone cement, is widely used for its self-polymerising and minimal adhesive attributes. Originally developed for dental applications, fixation in the bone with PMMA bone cement has largely contributed to the success of modern joint replacement. In stark contrast to this, the polymerisation reaction of methyl methacrylate is highly exothermic which can lead to cellular necrosis in the surrounding tissue. Much progress has been made in modelling fatigue failure of bulk cement and its interfaces with implant and bone. However, there still remains a scope for improvement.

Calcium polyphosphate (CPP) emerged as a new type of bio-ceramic for bone repair and continues to garner research interests. Many additives are further being tested to improve the biological properties of bone cement, while aiding in self-healing, improved infection resistance, and an increase in osteogenic up-regulation.

A recent study published in the Journal of Orthopaedic Surgery and Research analyses how a bio-composite bone cement could be advantageous over its PMMA counterpart in terms of structural stability. The former composed of chitosan and tri-calcium as additives to acrylic bone cement experiences relatively less ‘stress-shielding’, which accounts for its abilities to deliver structural stability in the long term. Another study indicates that reinforcement of PMMA bone cement showcases better biocompatibility, when supplemented with dopamine-coated strontium-doped calcium phosphate (SCPP) particles.

The fourth generation of cementing techniques

The first generation of cementing techniques involved the hand mixing of cement in a bowl – a rudimentary process, and long-term results for cemented implants are not impressed by today’s standards. Significant improvements have been made during the evolution from first to third generation of cementing techniques; from hand mixing to vacuum centrifugation.

With substantially increased knowledge regarding cement properties and the impact of bone preparation on the bone-cement interface, challenges associated with porosity were reduced and the importance of desirable cement mantle around the prosthesis was clearly understood. This had further led to development of the fourth generation of cementing techniques that involves the use of proximal and distal stem centralisers to insert prosthesis, ensuring an even cement mantle. These centralisers have increased the likelihood of achieving a complete cement mantle to reproduce. Additionally, in vitro experiments of distal and proximal centralisers have demonstrated improved bone penetration and higher interface of shear-strengths with low-viscosity cements.

Rise of minimally invasive surgeries to impact application

In recent years, medical and technological developments such as robot-assisted surgery, 3D bio-printing, and Artificial Intelligence (AI) in healthcare have had a profound effect on orthopaedic surgical procedures. Patients are increasingly demanding less invasive surgical techniques for much better outcomes and shorter hospital stays. Consequently, more attention is being paid to the development of a new generation of injectable and digitally applicable bone cements that are not only bioactive, biodegradable, and have excellent mechanical properties, but also compatible with newer surgical techniques.

For instance, in vertebroplasty – an effective, minimally invasive procedure for treating spinal fractures due to osteoporosis – bone cement is slowly injected under pressure, where the amount of cement and pressure are closely monitored to avoid any leakage. In the case of kyphoplasty, a path into the bone is created with two tiny tubes containing small inflatable balloons that raise the vertebrata to appropriate height. The cavities formed post removal of these balloons are filled with bone cement, which significantly reduces the potential risk of cement leakage.

The degree for interdigitation of bone cement is significantly influenced by its rheological properties. Its optimum penetration into cancellous bone structure remains paramount to achieve adequate load transfer across different interfaces. While an increasing number of research studies continue to focus on nanoparticle additives and enhanced bone cement interface, the convergence of surgical procedures with robotic technologies will call for advancements in robo-guided insertion of bone cement.

Author: Alice Ajit Mutum is a market research writer at Future Market Insights, a global research and consulting firm. She works closely with the healthcare team.