Custom Cutting Block Instrument vs Regular Instrumentation Total Knee Replacement (TKR)

A Double-blinded, Randomized, Controlled Trial of Total Knee Replacement Using Custom Cutting Block Instrument vs Regular Instrumentation

To determine if the use of patient-specific custom cutting blocks for implantation of total knee components results in improved limb alignment and component positioning compared to regular instrumentation.

This is a randomized controlled trial. Patients will be randomized to have their knee implanted using either the patient-specific custom cutting blocks or the regular instrumentation system. Functional and radiographic outcomes will be assessed in a blinded fashion. The Smith and Nephew Legion Primary® total knee system will be used in both groups; this is an implant with a good long term track record based on the Genesis II design. All surgeons have used and are familiar with the regular instrumentation. They will be instructed in the use of the patient-specific custom cutting blocks prior to study initiation.

Inclusion Criteria:

1. Patient is male or female ages 18 and over.
2. Patient is having primary total knee replacement
3. Patient is willing to sign the informed consent and to come for all study visits.

Exclusion Criteria:

1. Deformity of the femur preventing use of the intra-medullary guide utilized in the regular instrumentation set.
2. Necessity for the use of constrained implants. These types of implants have intra-medullary stems, therefore all bone cuts need to be referenced off intramedullary guides, making image guided bone cuts inappropriate.
3. Patients undergoing knee replacement revision surgery. Theses types of implants also have stems, making the use of image guided bone cuts inappropriate for the same reasons.
4. Patients scheduled for bilateral knee surgery (simultaneous or staged)