Clinical comparison of the midvastus and medial parapatellar surgical approaches

Abstract

The medial parapatellar approach and the midvastus approach are the two most commonly used surgical approaches in total knee replacement. This study compared surgical and clinical parameters associated with both surgical approaches in primary total knee replacement. One hundred nine patients who underwent bilateral primary total knee replacements had a medial parapatellar approach to one knee and a midvastus approach to the opposite knee. The prosthetic design and physical therapy were identical in all 109 patients. The patients and physical therapists were blinded to the type of approach used on each knee. The comparison included the surgical parameters of difficulty of exposure, surgical time, incidence of lateral retinacular release, and total blood loss. The clinical parameters of pain, range of motion, ability to perform a straight leg raise, and complications were compared at 8 days, 6 weeks and 6 months. The comparison between the two surgical approaches showed a statistically significant difference in four parameters, all of which favored the midvastus approach. The patients who had the midvastus approach required fewer lateral retinacular releases, had less pain at 8 days, had less pain at 6 weeks, and had a higher incidence of ability to straight leg raise at 8 days. There was no statistical difference between the two surgical approaches in all other surgical and clinical parameters. There was no increased difficulty of exposure using the midvastus approach when compared with the medial parapatellar approach even in patients with severe varus or valgus deformities. Notably, all clinical parameters were equal at 6 months. From a clinical standpoint, the midvastus approach had an advantage over the medial parapatellar approach because the patients had significantly less pain and had the ability to straight leg raise at 8 days. Because the managed care environment dictates a shorter hospital stay, patients who have the midvastus surgical approach have less pain and earlier control of the operative leg, and may be discharged from the hospital earlier. However, the clinical results at 6 months based on the patient's pain relief, range of motion, and ability to straight legraise were identical between the two surgical approaches.