Unilateral Primary Osteoarthritis of Knee
Conditions
Keywords
total knee arthroplasty, trabecular metal, bone mineral density
Brief summary
Osteoarthritis is a progressive disease afflicting to two thirds of Americans. Today, an estimated 43 million individuals have arthritis. By 2020, more than 59.4 million Americans will be affected by the disease. Despite the relative good track record of total knee replacement, it remains a biomedical device that can fail over time. A recent study looking at the current mechanisms of total knee replacement failures, listed polyethylene wear and osteolysis around implants. The material used for polyethylene insert as well as the conformity of articular surface of implants has been modified to decrease wear. While introducing modularity, the usage of metal backing in tibial base plates became obvious as it offered better stress distribution to the proximal tibial bone. However, it introduced other modes of failures. Micromotion has been demonstrated between the metal backing and the tibial liner, and produced backside polyethylene wear in 44% of implants at retrieval for revision. Factor influencing the surgeon's choice of implant include: reproductibility and longevity of results, technical difficulty of implantation, cost, and impact on bone stock. The modulus of elasticity of the tibial base plate has a direct effect on periprosthetic bone biology. Studies have described a significant decrease in postoperative Bone mineral density (BMD), adjacent to the implants, after total knee replacement. No study, to our knowledge, has looked at BMD in vivo after total knee replacement comparing different tibial base plate designs. Direct effect of changes in design on overall implant survival can be studied with randomized clinical trials isolating specific variables. No randomized clinical trial has looked at tibial insert stiffness and modularity, and it effect on bone density changes, synovitis, osteolysis or survivorship. In order to isolate stiffness and modularity as study variables, one would aim at randomizing an homogenous patient population undergoing total knee arthroplasty with implants of similar articular geometry designs with different tibial insert modularity and stiffness.
Detailed description
Number of patients: 80 Ages: 55 - 75 years old Sex: male and female Race: all
Interventions
DEVICETotal knee arthroplasty
Total knee arthroplasty using parapatellar approach and postero-stabilized implants.
Sponsors
Zimmer Biomet
CHU de Quebec-Universite Laval
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
55 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
* Tri-compartmental knee arthrosis * 55 to 75 years of age * Stable health condition
Exclusion criteria
* Inflammatory arthritis * Osteonecrosis * Infection * Amputation (AK or BK) * Biphosphonates * Metal in the proximal tibia (25cm) * History of fracture or osteotomy * Ligament instability
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Bone Mineral Density (%) from baseline initial value | post-operative 7 to 10 days, 6,12,24 months | Evaluation of Bone Mineral Density using dual energy x-ray absorptiometry (DEXA) scan under tibial base plate implant after Total knee arthroplasty. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Western Ontario & McMAster University Osteoarthritis sCore (WOMAC)change in time. | Pre-operative, 6,12,24,60 months | Standardized clinical evaluation instrument specific to Total knee arthroplasty population. |
| number of study subject with implant loosening | 12, 24, 60 months | Radiological evaluation of implant loosening according to Radiographic Knee Society Score at follow-up after total knee arthroplasty. |
| Knee injury and Osteoarthritis Outcome Score (KOOS) change in time. | pre-operative, 6,12,24,60 months | Standardized clinical outcome instruments specific to total knee arthroplasty population. |
| SF-36 score | Pre-operative, 12,24,60 months | Standardized General health evaluation and quality of life measuring instrument. |
Countries
Canada
Outcome results
None listed