Innovation & Evolution in Hip Replacement Surgery: Highlights from the Keggi–Rubin Hip Implant Collection at Yale University

Technology & Engineering Highlights

In the last decade, the combined work of surgeons and engineers has led to continued advancements in medical technology. New developments have enabled surgeons to create uniquely personalized surgical plans with more accurate and predictable outcomes. The recent incorporation of computer navigation and robotics in total hip replacement has provided surgeons with an enhanced understanding of implant position, bone conservation, and patient anatomy.

Custom Triflange Component

A 77-year-old female presented to Dr. Rubin at Yale New Haven Hospital with a loose hip replacement shell and a severely deformed left acetabular (pelvic) socket. She had previously undergone multiple revision surgeries, including one in the past year to repair a broken constrained liner; however, these were ultimately unsuccessful. Due to her surgical history and asymmetric bone loss in the pelvic socket, surgeons decided to create a custom tri-flange cage, shaped to fit her socket’s unique anatomy. A CT scan was taken and used to make the 3D model of her bony defect (on the right). The CT of her left hip was also processed to customize a 3D model of the cage to fit precisely within this defect. The final implant was then 3D printed out of titanium with a hydroxyapatite back coating. Since the surgery took place in September 2017, the patient has needed no further revisions, and her bone has grown in and around the cage, remodeling back to normal. The X-ray series below shows the patient’s left hip with the loose shell before surgery, the hip with the cage four months post-op, thirteen months post-op, and two years post-op.

Intellijoint

Intellijoint HIP is a surgeon-controlled, computer navigation system for total hip arthroplasty (THA). It provides real-time, intraoperative measurements for accurate implant alignment for cup position (orientation, depth, and height), as well as femoral parameters (leg length and offset). Yale Orthopaedics has been utilizing this technology for primary and revision total hip replacement, utilizing both the anterior and posterior surgical approaches. This technology is now also being used for total knee replacement at Yale.

Surgeon operating using Intellijoint HIP, from the Intellijoint Surgical website

Screenshot from video demonstrating the Intellijoint HIP, from the Intellijoint Surgical website

Mako Robot

Screenshot from Mako SmartRobotics Overview.

Stryker’s mako robot system uses 3D-CT scanning to create a virtual 3D model of a patient’s bony anatomy. This allows the surgeon to plan and perform total hip replacements that are unique to the patient’s anatomy. First, a CT scan is taken of the patient’s arthritic joint, which is processed by the mako robot’s team of clinical engineers. Prior to surgery, the surgeon virtually customizes the position of the implant’s components to recreate the hip’s center of rotation, maintain proper leg length, reduce the likelihood of dislocations, and select the implants that best fit the hip’s dimensions. During surgery, the surgeon navigates the Stryker robotic arm in accordance with the personalized, CT-based surgical plan. mako robotic total hip arthroplasties have resulted in greater bone conservation, more accurate implant placement, fewer surgical complications, and an increase in patient satisfaction.

Model of Mako robot, in silver

Case 7 photograph of physical exhibition in Cushing Rotunda, Cushing/Whitney Medical Library- Technology & Engineering Highlights