A COMPARATIVE STUDY OF THE MIDVASTUS AND MEDIAL PARAPATELLAR APPROACHES FOR TOTAL KNEE ARTHROPLASTY IN THE EARLY POSTOPERATIVE PERIOD

Abstract

Introduction: The commonest surgical approach for total knee arthroplasty is medial parapatellar approach. This involves splitting the quadriceps tendon, potentially destabilising the extensor mechanism. The midvastus approach involves splitting the vastus medialis muscle instead of entering the quadriceps tendon, therefore, minimising interruption of the extensor mechanism without compromising the exposure of the knee.

Objective: To compare clinical parameters associated with medial parapatellar and midvastus approaches for total knee arthroplasty in the early postoperative period.

Methods and results: We present a prospective observational study of 88 patients undergoing primary total knee arthroplasty using medial parapatellar or midvastus approach (44 in each group). The prosthetic design and physical intervention was standardised in all the patents. The Oxford Knee Score, pain scale, knee flexion, unassisted straight leg raise, standing and walking were compared at 3^rd, 5th and 7^th day postoperatively, then at 6 weeks and at 3 months. The patients and physiotherapist were blinded to the type of approach used. The average age was 67 years (range 42 to 88). There were 49 women and 39 men. The average hospital stay was 7 days (range 2 to 15). There was statistically significant difference in duration of hospital stay, unassisted straight leg raise and standing at 3 days (p=0.001) and pain scale at 5 days, all in favour of midvastus approach. There was no statistically significant difference in Oxford Knee Scores and duration to achieving full flexion and walking. The average duration to achieving straight leg raise for the midvastus group was 5 days and for the medial parapatellar approach group was 8 days

Conclusion: The study shows that total knee arthroplasty performed through the midvastus approach resulted in less postoperative pain, earlier unassisted straight leg raise and ambulation, therefore, shorter hospital stay as compared to medial parapatellar approach. This may be of benefit to the patients due to less discomfort after surgery, and to the healthcare system due to shorter hospital stay for patients.