STAR prosthetic system and the biomechanical considerations in total ankle replacements

The ankle is a complex joint that plays a crucial role in our ability to move. It has many parts that work together, including bones and ligaments. Over time, the ankle can become damaged due to injury or wear and tear, making it difficult to walk and move around. Traditionally, surgery to fix a damaged ankle involved fusing the bones together. However, newer treatments, like total ankle replacement (TAR), are now available.

Understanding Ankle Biomechanics:

To understand TAR better, it’s important to know how the ankle works. The ankle joint experiences a lot of stress and pressure during movement, so any replacement system needs to be designed with this in mind. This review explores how TAR systems have evolved over time to better mimic the natural movement and function of the ankle.

Evolution of Ankle Replacement Systems:

Ankle replacement surgery is a relatively recent development compared to traditional fusion surgery. This section looks at the history of ankle replacement and how different prosthetic systems have been designed to improve patients’ mobility and reduce pain.

The Scandinavian Total Ankle Replacement (STAR):

One specific TAR system, called the Scandinavian total ankle replacement (STAR), is discussed in detail. This system consists of three components and is designed to closely match the natural anatomy and movement of the ankle. The review evaluates whether the STAR prosthesis effectively distributes stress across the joint and meets the biomechanical needs of the ankle.

The ankle is made up of three bones, various ligaments, tendons, and muscles. The talus bone sits within a groove formed by the tibia and fibula, while the tibia and fibula form the inner and outer ankle bones, respectively. This arrangement creates a stable structure that allows for movement in multiple directions, rather than just up and down like a simple hinge. Understanding the complex anatomy of the ankle is important for treating ankle injuries effectively.


In summary, this discussion has focused on how the ankle joint distributes stress during movement. Forces acting on the ankle can be broken down into different types, including compression, shear, and torsion. As ankle replacement surgery becomes more common, it’s essential to consider how prosthetic designs can accommodate these forces to ensure optimal function and longevity. While there is still some conflicting evidence, features like minimal bone removal during surgery and appropriately sized implants are crucial considerations for successful outcomes.

A seasoned orthopedic surgeon and foot and ankle specialist, Dr. Mohammad Athar welcomes patients at the offices of Complete Orthopedics in Queens / Long Island. Fellowship trained in both hip and knee reconstruction, Dr. Athar has extensive expertise in both total hip replacements and total knee replacements for arthritis of the hip and knee, respectively. As an orthopedic surgeon, he also performs surgery to treat meniscal tears, cartilage injuries, and fractures. He is certified for robotics assisted hip and knee replacements, and well versed in cutting-edge cartilage replacement techniques.
In addition, Dr. Athar is a fellowship-trained foot and ankle specialist, which has allowed him to accrue a vast experience in foot and ankle surgery, including ankle replacement, new cartilage replacement techniques, and minimally invasive foot surgery. In this role, he performs surgery to treat ankle arthritis, foot deformity, bunions, diabetic foot complications, toe deformity, and fractures of the lower extremities. Dr. Athar is adept at non-surgical treatment of musculoskeletal conditions in the upper and lower extremities such as braces, medication, orthotics, or injections to treat the above-mentioned conditions.