Electronic Thesis and Dissertation Repository

Thesis Format



Master of Science


Health and Rehabilitation Sciences

Collaborative Specialization

Musculoskeletal Health Research


Marsh, Jacquelyn D.


The minimally invasive midvastus (MMV) surgical approach for total knee arthroplasty (TKA) is a less invasive technique that has been proposed to accelerate recovery over standard TKA, however, advantages are not yet definitively established. We investigated the cost-effectiveness of MMV TKA versus the standard medial parapatellar (MPP) approach for TKA alongside a randomized controlled trial in patients with knee osteoarthritis. Patients reported resource use as well as indirect costs, and health outcomes were measured using the EQ-5D-5L and the Western Ontario and McMaster Universities Osteoarthritis Index over the 12-month study period. The results of our net benefit regression analysis suggest MMV TKA may be cost-effective compared to MPP TKA from the payer perspective at willingness-to-pay (WTP) values between $1000 and $2000, and WTP values between $2000 and $20,000 from the societal perspective.

Summary for Lay Audience

For patients with advanced knee osteoarthritis (OA), total knee replacement (TKR) is an established surgical procedure that has been shown to improve pain, function, and quality of life. Over the years, less invasive surgical approaches have been developed in efforts to improve short-term recovery, reduce complications, and shorten the length of stay in hospital following TKR. The midvastus approach is one such technique. The potential advantage of the midvastus approach over traditional approaches is that less soft tissue in the leg is cut during surgery, which may allow for faster recovery and thus reduce the length of stay in hospital.

A shorter length of stay may reduce the hospital costs of TKR, although it is unknown whether the potential financial savings will be outweighed by possible complications related to early discharge from the hospital.

Therefore, the aim of this study was to evaluate the clinical outcomes and costs of TKR using a midvastus surgical approach compared to the standard medial parapatellar approach in patients with knee OA. We randomly assigned consenting patients scheduled to have TKR to either surgical approach and followed them for 12-months.

Patients completed questionnaires on their health care resource use (e.g., number of physician visits, tests, medications) and indirect costs (e.g, time off work/volunteering) related to their surgery. They also completed surveys on health outcome measures such as health-related quality of life, pain, and movement before surgery, two-weeks, six-weeks, three-months, and 12-months after surgery. We calculated the average total costs and health benefits incurred by patients in each group over the 12-month study period.

We found patients who had TKR with the midvastus approach experienced slightly greater health benefits than patients who had standard medial parapatellar TKR. Midvastus TKR patients also incurred fewer costs when considering societal costs which includes direct and indirect costs. Our findings highlight the importance of investigating patient-reported outcome measures and indirect costs. These results will help inform a future study evaluating the safety and cost-effectiveness of outpatient TKR, where patients are discharged from the hospital on the same day as their surgery.