CORI® Robotics-Assisted Knee Replacements

Your surgeon will size and position the partial knee implant with computer and robotic assistance.

The CORI® robotic system provides assistance through an advanced computer program that relays precise information about your knee to a robotics-assisted handpiece used by the surgeon during the procedure.

By collecting patient-specific information, the surgeon is able to establish spatial boundaries for the robotics-assisted handpiece to assist in removing the damaged surfaces of your knee, balance your joint, and position the implant with accuracy and precision.3

Partial knee replacement is a potential alternative to total knee replacement for patients with early to mid-stage osteoarthritis that is generally limited to one compartment of the knee. The procedure removes and replaces the damaged portion of the knee with an implant, sparing the cruciate ligaments that are vital to knee stability, and preserving healthy bone and cartilage. In contrast to total knee replacement, partial knee replacement offers patients: 

• Less pain (1)
• A more normal feeling knee (1)
• Smaller incisions (2)
• Quicker rehabilitation (1)

The surgeon will typically make a 10cm - 15cm incision along the front of your knee, just to the side of the knee cap, to access the damaged area and inspect the knee. Special trackers are secured to both the thigh bone (femur) and shin bone (tibia) with four, 3.2mm pins that are placed through small incisions in the skin. These trackers are crucial to the precision of the system as they provide a constant reference point for the robot as the surgeon collects your anatomical data and prepares the joint surfaces. 

The anatomical data collected is used to generate a 3-dimensional virtual model of your knee, which the surgeon uses to precisely plan your partial knee replacement. With the robotic assistance system, proper implant placement and knee balance, important to a successful surgery, are first achieved virtually. 

When the surgical plan is set, the CORI® robotics-assisted handpiece is used by the surgeon to accurately resurface the joint as he or she guides the instrument over the damaged femoral and tibial bone. After the damaged bone and cartilage have been removed and the implants are in place, the incision is thoroughly cleaned and closed to complete the procedure.

Your surgeon will size and position the total knee implant with computer and CORI® Surgical System. 

Computer assistance is used to collect the unique shape and motion of your knee to virtually plan the procedure. CORI® Surgical System is used to accurately perform the procedure. 

The extra layer of planning and precision provided by the system aims to ensure the procedure is performed exactly as your surgeon intends. 

CORI® does not perform the procedure; rather it assists your surgeon by providing accuracy and precision (3) – crucial to the success of the surgery.

You will first be placed under anaesthetic to relax your body for surgery and block pain. The correct form of anaesthetic will be discussed and determined prior to surgery with your surgeon and anaesthetist. 

Your surgeon will then make an incision that extends several centimetres above the knee cap to several centimetres below the knee cap. Using the robotic system, special trackers are secured to both the thigh bone (femur) and shin bone (tibia) with four small surgical pins placed through tiny incisions in the skin. These trackers are crucial to the precision of the system as they provide a constant reference point to the surgeon throughout the procedure. Using computer assistance, the unique shape and motion of your knee are collected by the surgeon. 

This allows for a three-dimensional model of your knee to be generated and used by the surgeon to plan the procedure. Proper implant size and position will be determined at this time. Once your surgeon virtually determines the correct implant size and positioning, a handheld roboticsassisted tool is used to accurately position bone removal cut guides. These cut guides enable the surgeon to use a surgical saw to remove your damaged knee bone, making room for the implant. 

The extra layer of precision provided by the robotic system is designed to enable accurate cut guide placement. The system does not perform the procedure; rather it assists your surgeon by providing accuracy and precision (3) – crucial to the success of the surgery. Once the implant is in the final position, the incision is thoroughly cleaned and closed, completing the procedure.

If you’ve been recommended by your doctor for knee replacement surgery and are interested in CORI®, then contact our enquiry team to find out more or book an appointment. 

Content provided by Smith & Nephew January 2025

1. Hall et al., “Unicompartmental Knee Arthroplasty (Alias Uni-Knee): An Overview With Nursing Implications,” Orthopaedic Nursing, 2004; 23(3): 163-171. 

2. Repicci, JA, et al., “Minimally invasive surgical technique for unicondylar knee arthroplasty,” J South Orthopedic Association, 1999 Spring; 8(1): 20-7. 

3. Lonner, et al. “High Degree of Accuracy of a Novel Image-free Handheld Robot for Unicondylar Knee Arthroplasty in a Cadaveric Study.”Clinical Orthopaedics and Related Research. Advanced online publication. DOI 10.1007/s11999-014-3764-x5 American Association of Orthopaedic Surgeons (2014). AAOS.org.

Robotics-assisted surgery is not for everyone. Children, pregnant women, patients who have mental or neuromuscular disorders that do not allow control of the knee joint and morbidly obese patients should not undergo a procedure. Knee replacement surgery is intended to relieve knee pain and improve knee functions. However, implants may not produce the same feel or function as your original knee. There are potential risks with knee replacement surgery such as loosening, fracture, dislocation, wear and infection that may result in the need for additional surgery. Longevity of implants depends on many factors, such as types of activities and weight. This information, including postoperative care, is provided for educational purposes only. Smith+Nephew does not provide medical advice. In no event shall Smith+Nephew be liable for any damages whatsoever arising out of the use of or inability to use the expressed views. Consult your surgeon to determine if a roboticsassisted procedure is right for you. CORI® robotics assisted surgery is intended to assist the surgeon in providing software-defined spatial boundaries for orientation and reference information to anatomical structures during orthopaedic procedures. CORI® Surgical System is indicated for use in surgical knee procedures, in which the use of stereotactic surgery may be appropriate, and where reference to rigid anatomical bony structures can be determined. These procedures include unicondylar knee replacement (UKR), patellofemoral arthroplasty (PFA), and total knee arthroplasty (TKA)