GMK Revision Knee System is part of the Medacta GMK® (Global Medacta Knee) Total Knee System and is indicated when a higher level of varus/valgus constraint is needed. The external shape of the GMK® Revision femoral component is identical to that of GMK® Primary. The GMK® Revision differs from GMK® Primary by three important design features:

i. The addition of a box which allows a stem to be inserted into the femoral canal; ii. The addition of screw lugs so that augments can be placed on the distal and posterior resections, and; iii. The box which also allows various levels of constraint to be added to the polyethylene insert. The tibial component offers the ability to place augments.

Indications for Use:

The GMK® Total Knee System is designed for cemented use in total knee arthroplasty if there is evidence of sufficient sound bone to seat and support the components.

This knee replacement system is indicated in the following cases:

• Severely painful and/or disabled joint as a result of arthritis, traumatic arthritis, rheumatoid arthritis or polyarthritis
• Avascular necrosis of femoral condyle
• Post traumatic loss of joint configuration
• Primary implantation failure
• Ligamentous Instability

Tibial augments are to be attached to the tibial baseplate with both the fixing cylinders and bone cement. In case a semi-constrained liner is used, an extension stem must be implanted both on the tibial and on the femoral component.

GMK® Revision femoral components are manufactured of Cobalt Chromium Molybdenum (CoCrMo) according to ISO 5832-4:1996, Implants for Surgery- Metallic materials - Part 4: Cobalt-Chromium-Molybdenum Casting Alloy, the same as the GMK® Primary femoral components. They have an asymmetric patellar groove (left and right) with different radii of curvature in coronal plane as well as non-parallel anterior and posterior cuts (wedge shape). The GMK® Revision posterior stabilized femoral components are designed for use without cruciate ligaments when additional stability is required to prevent subluxation of the femur to the tibia in flexion, same as the GMK® Primary femoral components.

In case of severe bone loss, the tibial cones and femoral cones may be used to respectively reinforce the proximal tibia cavity and the distal femoral cavity, providing structural support and load redistribution on the remaining bone. Being an integral part of revision TKA for patients with such bone loss, the clinical outcomes for revision TKAs using the cone components are important for the knowledge regarding performance and survivorship of the Revision TKA as a whole.

Inclusion Criteria:

• Subjects underwent revision total knee replacement for any type of etiology (Osteoarthritis, Avascular necrosis, Rheumatoid Arthritis, Post-traumatic Arthritis, Polyarthritis, Primary implantation failure, Infection, Ligamentous Instability)
• Subjects must have received a Medacta GMK Revision component using 3D metal tibial and femoral cones
• Must be at minimum 1 year (12 months) post-treatment
• No age limit criteria

Exclusion Criteria:

• Subjects with neuromuscular or neurosensory deficiency, which would limit the ability to assess the performance of the device
• Subjects that were incarcerated at the time of surgery.
• History of alcoholism
• On chemotherapy or radiation therapy during the time of interest
• Habitual use of narcotic pain medications prior to surgery or after surgery for reasons other than knee pain
• History of a metabolic disorder affecting the skeletal system other than osteoarthritis or osteoporosis
• History of chronic pain issues for reasons other than knee pain
• Progressive local or systemic infection during time of interest
• Muscular loss, neuromuscular disease, or vascular deficiency of the affected limb
• Obesity or excessive weight of subject

The total expected number of subjects to be included in this study is a minimum number of 50. This number has been estimated according to the number of surgeries that have been performed and is considered in-line with observational studies published in literature.