Intellijoint HIP®: a 3D mini-optical navigation tool for improving intraoperative accuracy during total hip arthroplasty

Abstract

Total hip arthroplasty is an increasingly common procedure used to address degenerative changes in the hip joint due to osteoarthritis. Although generally associated with good results, among the challenges associated with hip arthroplasty are accurate measurement of biomechanical parameters such as leg length, offset, and cup position, discrepancies of which can lead to significant long-term consequences such as pain, instability, neurological deficits, dislocation, and revision surgery, as well as patient dissatisfaction and, increasingly, litigation. Current methods of managing these parameters are limited, with manual methods such as outriggers or calipers being used to monitor leg length; however, these are susceptible to small intraoperative changes in patient position and are therefore inaccurate. Computer-assisted navigation, while offering improved accuracy, is expensive and cumbersome, in addition to adding significantly to procedural time. To address the technological gap in hip arthroplasty, a new intraoperative navigation tool (Intellijoint HIP®) has been developed. This innovative, 3D mini-optical navigation tool provides real-time, intraoperative data on leg length, offset, and cup position and allows for improved accuracy and precision in component selection and alignment. Benchtop and simulated clinical use testing have demonstrated excellent accuracy, with the navigation tool able to measure leg length and offset to within <1 mm and cup position to within <1° in both anteversion and inclination. This study describes the indications, procedural technique, and early accuracy results of the Intellijoint HIP surgical tool, which offers an accurate and easy-to-use option for hip surgeons to manage leg length, offset, and cup position intraoperatively.

Keywords: Intellijoint HIP; cup position; intraoperative; leg length; offset; total hip arthroplasty.

Conflict of interest statement

WGP has received consultancy fees from and is a shareholder in Intellijoint Surgical, Inc. JMM is an employee of Intel-lijoint Surgical, Inc. The authors report no other conflicts of interest in this work.

Figures

Figure 1

The Intellijoint HIP 3D mini-optical navigation tool. Notes: The camera (A), enclosed in its sterile drape, is attached to the pelvic platform (B) via 2 screws (C). The tracker (D) is magnetically attached to the femur platform (E). The camera captures the movements of the tracker when registering the native orientation or while trialing the implant components and thereafter relays the information to a workstation for review by the surgeon.

Figure 2

The Intellijoint HIP system. Notes: The camera (A) is enclosed within a sterile drape (B) and fixed to the pelvis via a pelvic platform (C). The camera transmits positional data for display on the workstation (D), placed outside of the sterile field. Control buttons on the camera (E) allow the surgeon to interact with the system and manipulate the workstation display without leaving the sterile field.

Figure 3

Representative images of the workstation screen indicating data provided to surgeons in real time. Notes: Measurements of leg length and offset (A) and cup position (B) are displayed during trialing and once sizing is finalized. A summary page (C) displays all relevant data for review.

Figure 4

The acetabular benchtop phantom. Notes: Discrete angles, confirmed by a calibrated electronic level, provide reference angles, which are then measured by the navigation tool. During testing, angles are computed from the movement of the tracker (A) captured by the camera (B).

Figure 5

Benchtop phantom configured for leg length and offset testing. Note: The camera (A) captures the position of the tracker (B) as it is moved about the simulated hip joint (arrow).