ISAKOS: 2019 Congress in Cancun, Mexico

2019 ISAKOS Biennial Congress ePoster #975


Mini-Midvastus Approach Shows Improved Short-Term Outcomes in Primary TKA Compared to Medial Parapatellar Approach

Dylan Young, BS, Gilbert, AZ UNITED STATES
Sarah Shi, MS, Mahwah, NJ UNITED STATES
Kate Matthews, MA, Anthem, AZ UNITED STATES
Kipling P. Sharpe, MD, Gilbert, AZ UNITED STATES

OrthoArizona, Gilbert, AZ, UNITED STATES

FDA Status Cleared


An extensive 3 year study including 381 patients showed a significant benefit in short-term outcomes for patients that underwent total knee arthroplasty using the minimally invasive midvastus approach when compared to the standard medial parapatellar approach.


The benefits and drawbacks of minimally invasive surgery (MIS) for total knee arthroplasty (TKA) have been a topic of debate since its introduction. We tested the hypothesis that primary TKA, through a mini-midvastus (MMV) approach, would provide better subjective and objective outcomes when compared to the medial parapatellar (MPP) approach up to one-year postoperatively. One cementless TKA design was used (Triathlon, Stryker, Mahwah, NJ). The study was not randomized. Each surgeon chose their preferred surgical approach and did not mix surgical approaches. A total of 381 patients (446 knees) were included. Progress was assessed with two scoring measures, the 2011 Knee Society Score (KSS) and the Oxford Knee Score (OKS). KSS patient-reported portions included Patient Satisfaction (KSS-S), Patient Expectation (KSS-E). and Functional Knee Score (KSS-F). There was one surgeon-reported component, the Objective Knee Score (KSS-O) that was used to measure objective progress. OKS scores were obtained to solely measure the subjective progress of the patient. KSS scores were obtained preoperatively, at six weeks, six months, and one year, while OKS scores were obtained preoperatively, at six weeks and one year. Although no significant trends were noted when comparing KSS-E, KSS-S, and OKS for the two cohorts, the KSS-F and KSS-O scores were significantly higher in the MMV cohort when compared to the MMP cohort at all time points up to one year postoperatively. Our results suggest early advantages of the MMV approach compared to the MPP approach up to one-year post-TKA in primary procedures.