Robotic Assistance for Complex Hip Reconstructions

By Peter Surace, MD, and Michael Bloomfield, MD

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The difference between a hip replacement that is successful and one that has complications may be millimeters, due to inaccuracies in size and position.

Many tools have been developed to help surgeons improve precision in total hip arthroplasty. For example, the use of robotics has helped reduce leg length discrepancy, improve implant position and increase postoperative stability.

While robotic guidance has proven beneficial in standard joint replacement, at Cleveland Clinic we also are using it off-label for complex hip reconstructions, including in patients with:

Anatomic abnormalities
Previous hip operations
Pre-existing hardware that we need to navigate around
Substantial bone loss

In these situations, the stakes are higher, the risk of complication is elevated, and getting a prosthesis in the right position is more challenging.

How the robot helps optimize complicated cases

When patients have had previous acetabular fractures treated with open reduction and internal fixation, or plates and screws, we now use the robot to successfully plan a hip replacement around the implanted hardware. This can help us avoid a more invasive procedure required to remove the hardware. Using CT-based templating, we know ahead of time whether we can work around these implants or must plan to remove them.

In patients who had childhood or adolescent surgeries and now have either retained implants or substantial changes to their anatomy, we can plan the surgery three-dimensionally on the robotic platform. This helps us achieve a precise hip replacement without risks that otherwise could present.

In other cases, where the anatomy is so distorted, planning the surgery entirely on the robotic platform informs us if we will need certain additional implants. We know ahead of time when we need less commonly used sizes or models of implants and even tools such as acetabular augments. Rather than “finding out as we go” during surgery, we can carefully plan the procedure and execute it more methodically.

As a result, preparations for surgery are better and the potential for surprises during more complex procedures is minimized. By using the robot, complex surgeries (as in the three cases below) are becoming more routine and standardized — and, thus, we believe better and safer for the patient.

Case 1: Deformity

A chronic acetabular fracture was treated nonoperatively at another hospital and, over time, developed into a substantial deformity. The entire hip shifted medially, causing a severe discrepancy in leg length.

With conventional hip replacement, it would have been difficult to plan the exact size of the socket and ensure its lateral positioning, where the center of rotation belongs. However, with the robotic platform, we were able to plan removal of the hip easily, navigate our screw trajectory and achieve an outstanding press-fit with minimal difficulty.

X-rays of hip deformity — Plain X-ray and robotic X-ray demonstrating substantial deformity of the left hip — shortened 1.4 cm, with chronic acetabular fracture.

Robotic surgery planning — Robotic reaming planning (highlighted in green). This planning helps surgeons identify the ideal reamer size, one that will achieve purchase between the anterior and posterior wall. It also helps surgeons prevent the reamer from going too medial into the defect, an easy error without robotic support.

Robotic planning and X-ray of hip replacement — Left: Robotic template of the socket position. Right: Postoperative X-ray demonstrating excellent accuracy of the robotic plan and execution.

Case 2: Revision surgery

A patient had an infected total hip that had been removed. An antibiotic spacer was placed, leaving the patient functionally without a hip. They had extreme leg length discrepancy and substantial bone loss.

We used the robotic platform to reproduce the anatomy with extreme precision, matching it to the native hip. This alleviated much of the guesswork and inaccuracy inherent in difficult cases like this.

X-ray showing hip deformity — An antibiotic spacer of the right hip. This X-ray shows severe shortening and substantial acetabular bone loss.

X-ray of hip replacement — The new construct, with an accurately placed, robotically guided socket. The anatomy is restored, and leg lengths are matched.

Case 3: Retained hardware

This patient had bilateral hemi-resurfacing arthroplasties in the remote past for avascular necrosis. The patient presented with severe groin pain due to acetabular chondral wear.

Use of off-label robotic assistance (with metal artifact reduction CT) helped us accurately plan reconstruction in the setting of retained hardware and achieve excellent acetabular registration.

Robotic template planning hip reconstruction — Presurgical CT-based templating showing the planned acetabular reconstruction around the existing femoral head resurfacing and patient-specific spinopelvic mechanics.

Robotic planning of hip replacement — Accuracy of the intraoperative bone registration was not compromised by existing hardware.

Better care for patients with higher risks of complication

In summary, robotic hip replacement has proven successful in straightforward cases. At Cleveland Clinic, where we see a substantial number of highly complex reconstructions, we now are using robotic systems to provide more efficient, accurate and easier care for patients with larger problems and a higher risk of complication.

Drs. Surace and Bloomfield are staff physicians in the Department of Orthopaedic Surgery at Cleveland Clinic.