Imageless Navigation System Assists Hip Replacement Surgery

A hand-held total hip replacement (THR) navigation system reduces overall radiation exposure by utilizing imageless technology.

The Naviswiss (Brugg, Switzerland) Naviswiss miniature hip navigation system uses proprietary optical tracking technology to provide real-time intra-operative measurements (down to the degree) to accurately determine anteversion, inclination, leg length, and offset. When needed, ultra-lightweight NAVItag trackers are attached to reference the anatomy. The P-tag is fixed to the pelvis with two 3 mm pins via small stab incisions; it serves as fixpoint for cup navigation. The M-tag is seated on the cup impactor. And the F-tag is attached to the femur via a single pin; it is used for leg length and offset navigation.

Relationships between the tags are documented using the camera. Cup inclination and anteversion are displayed in real-time during alignment and insertion. When reducing the joint, the navigation assists in adjusting leg length and offset. Final implantation parameters are documented in a detailed surgical report. The open platform system works with all major hip implants and surgical approaches, as does the magnetic attachment of the NAVItag, which adheres to the cup impactor. The Naviswiss system is portable, and can be easily transported between operating rooms, supporting multiple procedures.

“At Naviswiss we strive to make hip navigation smarter by putting it in the hands of the orthopedic surgeon. Based on our patented Swiss technology, the Naviswiss system guides the surgeon through three easy steps,” said Jan Stifter, CEO of Naviswiss. “The relevant results are provided with digital precision and are used to precisely position the implant and to document the outcome. We are convinced that our system helps improve the quality of surgery to benefit the patient and health care system.”

A hip replacement implant is a ball-and-socket mechanism, designed to simulate a human hip joint and mimic its movement. Typical components include a stem that inserts into the femur, a ball that replaces the head of the thigh bone, and a shell that lines the hip socket. Assessment of individual patient pelvic tilt and digital measurement of leg length and offset changes are used to achieve more consistent leg length restoration.

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