Personalized Knee Arthroplasty: ConforMIS

What personalized knee arthroplasty is

In a conventional knee replacement, the surgeon chooses from a set of manufactured implant sizes and shapes the bone to fit the closest match. In a personalized, or patient-specific, approach the sequence is reversed. A CT scan of the affected leg is used to build a three-dimensional model of that individual knee, and the implant components are then manufactured to the contours of that model. ConforMIS is the patient-specific knee system associated with this approach.

The same imaging is generally used to produce single-use guides and instruments made for that particular knee, intended to help position the components according to the plan created before the operation. The underlying operation is still a knee replacement: damaged surfaces are removed and resurfaced, alignment is addressed and the soft tissues are balanced. What differs is that the components and the cutting guides are derived from your own anatomy rather than from an averaged design, and that much of the planning is completed before you enter the operating room. Personalized components can be made for total knee replacement and, in appropriate cases, for partial replacement of a single compartment.

Symptoms that often lead people to ask about it

• Arthritis pain that limits walking, stairs, work or sleep despite non-surgical care
• Knee stiffness, swelling or a joint that no longer straightens or bends comfortably
• Bowing or angulation of the leg that has changed over time
• Concern about how well a standard implant will suit an unusually small, large or asymmetric knee
• A wish to understand every option before committing to knee replacement

How it is evaluated

Candidacy is assessed the same way as for any knee replacement: history, examination of alignment, motion, ligament stability and gait, and standing x-rays that show the joint under load. If a personalized approach is being considered, a CT scan following the manufacturer's protocol is generally obtained, and the components and instruments are then produced ahead of the surgical date. That production time means the operation is usually scheduled with some lead time. Overall health, other medical conditions and anesthesia planning are reviewed as they would be for any joint replacement.

Treatment options in general terms

Before any replacement is scheduled, non-surgical measures are generally revisited. These may include:

• Therapy and conditioning. Strengthening, motion work and low-impact activity.
• Medication and injections. Anti-inflammatory options and injection categories that may be appropriate for arthritis pain.
• Bracing and activity change. Support or unloading of the affected compartment.

If replacement is appropriate, the options that may be compared include:

• Standard total knee replacement. Off-the-shelf components in a range of sizes, fitted during the operation.
• Personalized total knee replacement. Components and instruments made from imaging of your own knee.
• Partial replacement. Resurfacing a single compartment, in standard or personalized form, when arthritis is confined to one part of the joint.

What to expect when you consult Dr. Wolfson

Dr. Wolfson is board certified in the United States and Canada. If you are interested in a personalized implant, the consultation covers whether your arthritis pattern and anatomy make you a reasonable candidate, what the imaging and manufacturing process involves, and how this approach compares with the standard alternatives so you can weigh them yourself. Second opinions are welcome, and telemedicine visits are available.

This page provides general information about personalized knee arthroplasty and is not medical advice. It is not a substitute for examination, imaging and diagnosis by a qualified physician. Every case is different and requires individual evaluation. If you have severe pain, an obvious deformity, loss of function, fever, or an injury from a significant accident, seek medical care promptly.

Contact Dr. Wolfson if you would like to setup an appointment. If you are a new patient, please book all in-person appointments with Dr. Wolfson via telephone.

If you live outside of the San Francisco Bay Area, you can request a complimentary phone consultation with Dr. Wolfson to assess your case. Please call or e-mail us to set up your complimentary consultation.

Call: (415) 221-4400

E-mail: [email protected]