ConforMIS^® Partial Knee Replacement

Partial knee replacement simply means that only a part of the knee joint is replaced through a smaller incision than would normally be used for a total knee replacement.

Osteoarthritis, the most common type of arthritis is a degenerative joint disease in which the joint cartilage gradually wears away. As a result bones rub together resulting in extreme pain. The knee can be divided into three compartments:

• Patellofemoral – the compartment behind the kneecap
• Medial compartment – the compartment on the inside of the knee
• Lateral compartment – the area on the outside of the knee joint

ConforMIS^® has developed the personalized knee resurfacing implants with unique advantages against traditional knee replacement options. To design a personalized implant for every individual, surgeon will perform the CT scan of the affected knee of the patient. A 3D image of a patient’s knee is created from CT scans and an implant is designed to conform exactly to individual size and shape.

Personalized implants by ConforMIS^® are of various types including iTotal^®CR , iUni^®G2 , iDuo^®G2 .

The ConforMIS iTotal CR is an individualized patient specific implant for replacement of all the three compartments of the knee. It is thus most appropriate for patients with knee arthritis and knee damage requiring implant for not one or two but all the three compartments of the knee. It is designed specifically to match the natural shape of the articulating surfaces of the patient’s knee. This is done by mapping the articulating surfaces of the femur and tibia using the data from the CT scan of the patient’s knee. It also comes with disposable patient specific iJig instrumentation with built-in image guidance which simplifies the surgical procedure and improves the outcome.

The several advantages of this patient specific or iTotal customized total knee replacement implants over the regular traditional implants are:

• No compromise on the size of the implant as is patient specific
• Provides better fit of the implant as the implant conforms to the patient’s unique shape of the articulating surfaces of the knee joint
• Maximizes the implants contact area decreasing the polyethylene contact stress thereby prolonging the life of the implant
• Preserves more natural bone
• Maximizes proximal tibial coverage and thus reduces the risk of tibial implant caving in and loosening

Indications for use:

• Chronic joint disease due to trauma, osteoarthritis, rheumatoid arthritis or osteonecrosis of the knee
• Moderate varus, valgus or flexion deformity with not much damage to the ligaments
• Revision surgery for failed osteotomy, hemiarthroplasty and unicondylar, patella-femoral or bi-compartmental implants

Note: The iTotal CR implant require the use of bone cement for fixation.

Although iTotal Customized total knee replacement systems are recommended in various conditions, they are not appropriate in patients with:

• Local or systemic infection
• Insufficient bone stock on the femoral or tibial surfaces
• Young patient with skeletal immaturity
• Severe fixed valgus or varus deformity of greater than 15 degrees
• Sensitivity to metals such as nickel
• Conditions of the knee joint such as osteoporosis, joint neuropathy and others in which the bone, muscle or nerves of the knee to be operated are compromised
• Severe instability due to major loss of osteochondral structure or absence of collateral ligament integrity