Evaluation of Bone Mineral Density Changes Using Two Tibial Base Plate Designs in Primary Total Knee Arthroplasty in Young Patient

Randomized Clinical Evaluation of Bone Mineral Density Changes Using Two Tibial Base Plate Designs in Primary Total Knee Arthroplasty in Young Patients

Arthritic disease in people less than 60 years old is increasingly common. Younger, active individuals often present now to orthopaedic surgeons requiring treatment of knee osteoarthritis. Knee arthroplasty has been offered as a viable option to provide pain relief and improve function in the middle-aged patient.

In a previous study submitted for publication, the investigators have looked at BMD in vivo after total knee replacement comparing two different tibial base plate designs in cemented and uncemented implants in terms of stiffness and modularity, and its effect on bone density changes, synovitis, osteolysis or survivorship. The investigators found a difference of 18% in bone mineral density favoring trabecular metal implant over cemented modular metal-back implant in patient between 55 and 75 years of age. The trabecular metal implant thus behaved as it was expected and preserved bone density in an elderly population.

No randomized clinical trial has looked at cemented titanium tibial insert to uncemented trabecular metal tibia insert in young population. In order to isolate stiffness as study variable, one would aim at randomizing a homogeneous patient population undergoing total knee arthroplasty with implants of similar articular geometry designs with different tibial baseplate, titanium versus trabecular metal. The trabecular metal implant is closer to human bone modulus of elasticity.

THE GOAL OF OUR STUDY IS TO

1. Quantify the amount of bone remodeling 24 months after total knee arthroplasty using sequential dual-energy x-ray absorptiometry of the proximal tibia in younger and more active patients (less than 60 years of age).
2. Evaluate the evolution of functional outcome over a 24 months period using sequential subjective and objective clinical evaluations using the Knee Society Score (KSS) and Knee Injury and Osteoarthritis Outcome Score (KOOS) and Sf-12 v2 in this cohort of patients.
3. There is also an interest in looking at the activity level before and after the surgery (by using the Tegner Activity Level Scale and the UCLA Activity Level Scale) and to determine the ability to return to an active lifestyle and the impact on implant survival.

Two groups will be created:

Group 1: NexGen cemented modular metal-backed tibial implant (Titanium) Group 2: NexGen uncemented Trabecular Metal(TM) modular tibial implant A total of 88 patients will be recruited

Inclusion Criteria:

• Tricompartmental osteoarthritis of the knee
• Age, under 60 years old at the time of surgery
• Stable health (the patient should be able to undergo surgery and participate in a follow-up program based upon physical examination and medical history).

Exclusion Criteria:

• Diagnosis of inflammatory joint disease
• Diagnosis of osteonecrosis
• Infection; acute or chronic
• Any current metal hardware on the proximal 25 cm of the tibia
• History, remote or recent, of high tibial osteotomy or tibial plateau fracture
• Any collateral ligamentous instability in the affected knee
• Contra lateral below knee or above knee amputation
• Ongoing Biphosphonate pharmacotherapy
• Presence of clinically significant disease of the cardiovascular, renal, hepatic, hematologic,respiratory, endocrine, neurological, gastrointestinal, genitourinary, immune systems or other medical condition which is not well controlled.
• Participants of a study who have received an investigational drug or device within the last 30 days
• Patients unwilling or unable to cooperate in a follow-up program
• Bone deficit (subchondral cyst)
• Previous contralateral Total Knee Arthroplasty (TKA), ORIF, HTO
• Patella deficiency needing grafting or preventing patella resurfacing