The AndPlus Blog

In 1891, at the 10th International Medical Conference, Professor Themistocles Glück of Germany presented the results of an experiment in which he used ivory to replace the femoral head (the “ball” part of the ball-and-socket) of human patients with deteriorated hip joints.

This started several decades of research into joint prostheses. The 1940s saw the first use of metal as a material in joint replacement surgery. Further development of materials and techniques ensued, and different kinds of joints can now be replaced, including knees, shoulders, and fingers.

Joint replacement surgery is now commonplace, with hundreds of thousands of patients obtaining relief from arthritis and other joint ailments every year.

Issues With Joint Replacements

Still, some joint replacements suffer from post-operative complications. Historically, infections were the most common issues. As antiseptic methods and practices improved, infection rates declined, but other causes of prosthesis failure remained, including:

• Excessive wear between the prosthesis and attached bone, resulting in loosening of the prosthesis
• Metallic wear particles, which can cause inflammation of the surrounding tissue
• Fractures in the bone tissue attached to the prosthesis
• Joint instability caused by improper placement of the prosthesis, or weakness in the associated tendons
• Stiffness or loss of range of motion  
• Dislocation of the joint
• Blood clots in the area of the surgery
• Nerve or blood vessel damage from the surgery

Failure rates for joint replacements are not especially high, and the rate varies with factors such as the material used, the accuracy of the joint placement, and the condition of the patient’s bones, muscles, tendons, and other tissues. Many replacement joints last several decades before failing, and most last the lifetime of the patient without causing any trouble.

The trouble is that when there is failure, the only solution is to do it over, and these follow-up surgeries have a much higher failure rate. These surgeries (known in the business as “implant revisions”) are also costly, often triple (or more) the initial cost of the treatment.

Thus, it’s in everyone’s best interest to reduce the initial failure rate as low as possible.

How Technology Can Help

Every patient is different—there is wide variation in physical size, the condition of bones and other tissues, and the state of the problem that necessitates joint replacement. Thus, joint replacement surgery is never a one-size-fits-all proposition. Every treatment is personalized to the patient.

That variation and personalization are what makes these surgeries complex, and it drives many of the issues that ultimately cause replacement joint failure.

Advances in technology can help prevent many of these issues. Better imaging technologies, with higher resolution and greater precision can help surgeons make better decisions about the size and shape of the replacement parts and the surgical approach—that is, how to get in and out most efficiently while minimizing trauma.

But better imaging alone is not sufficient. Surgeons need improved tools to help them select the size and shape of the prosthesis components to prevent misalignment issues that so often cause repeat surgeries.

At AndPlus, working with joint replacement technology company Arthromeda, we created a web-based application to do just that. By leveraging our advanced development methodologies and tools, we developed a powerful, intuitive, user-friendly, and FDA-approved surgical planning tool called ArthroPlan, which Arthromeda now makes available to surgeons around the world. ArthroPlan uses digital templating to give surgeons the ability to visualize, in three dimensions, the right shape, size, and alignment of the prosthesis, based on high-quality medical imaging. The enhanced planning enables surgeons to more precisely plan the surgical treatment, and use of the tool has been shown to reduce replacement joint failures by 30%.

More to Come

The technological impact on joint replacement doesn’t stop there. There are more ways that technology can be brought to bear on improving patient outcomes. Consider:

• Materials. Healthy bones actually flex a bit as people walk, run, bend, sit, stand, or do almost anything. One problem with metal replacement joints is that they are much stiffer. Often, because the bone that a hip joint prosthesis is attached to flexes but the prosthesis doesn’t, the bone becomes damaged and loses its grip on the prosthesis. Advanced materials can solve this problem by giving prostheses the same strength and biocompatibility as conventional prostheses while also giving them the flexibility of natural bone.
• Imaging and modeling. Hips and knees are simple joints, just two bones in the former and three in the latter. Other joints, such as wrists and ankles, are much more complex and difficult to model, which is one reason why ankle and wrist replacements are much less common, although arthritis and other ailments can affect those joints too. Enhanced, high-resolution 3D imaging could help surgeons visualize these complex joints better, enabling them to see the exact problems and design the right prostheses to solve them.
• Surgical procedures. Advanced surgical tools are making it possible to perform minimally invasive joint replacement surgeries. Computer-aided and robotic surgery tools can help surgeons precisely position prostheses while minimizing damage to the surrounding tissue, thereby decreasing post-operative pain and shortening recovery times.

Not a Moment Too Soon

Particularly in developed countries, people are living longer, and populations are skewing older. As the population ages, the need for joint replacements will only increase. Technologies that help surgeons better plan and execute these surgeries will help improve the outcomes for thousands more patients every year. AndPlus is proud to be part of the mix, and we look forward to doing more for this critical need.