A comparison of midvastus and standard median parapatellar approaches in total knee arthroplasty

Abstract

Objective To compare the early functional outcome of midvastus approach with that of standard median parapatellar approach in total knee arthroplasty. Methods From March 2004 to March 2006, a total of 34 patients had bilateral total knee arthroplasty simultaneously in our department. The midvastus approach was randomized prospectively for one knee and the standard median parapatellar approach for the other. The comparisons were made in difficulty of exposure, surgical time, blood loss, lateral retinacular release, postoperative pain at rest and movement, straight leg raising time, time for active 90^oknee flexion, visual analog scale （VAS） scoring, range of motion and complication. Results The comparisons revealed significantly less blood loss [（286.0±29.8） mL vs. （368.0±35.8） mL, P 〈0.05], fewer lateral retinacular releases for valgus knee（20% vs. 50%, P 〈 0.05）, less pain in the first week（ P 〈 0.05 ）, earlier straightlegraising[（1.8±0.3） d vs. （4.5±0.8） d, P 〈0.01], earlier 90^o knee flexion [（3.2±0.8） d vs. （7.1±1.2） d, P 〈0.01] and greater knee flexion at 45 days [（107^o±20^o） vs. （98^o±12^o）, P 〈 0.05] in the midvastus group. Conclusion The midvastus approach, which is based on diminished disruption of extensor mechanism and peripatellar plexus of vessels, offers advantages over the standard median parapatellar approach in the early rehabilitation period. Key words: Arthroplasty, replacement, knee; Arthritis; Surgical approach