Abstract
The subvastus approach to the knee has been described as early as 1929. This approach for primary total knee arthroplasty (TKA) maintains the integrity of the quadriceps mechanism and maintains the vascularity of the patella.
We have conducted a prospective, double blind, randomised trial to evaluate the quadriceps function in TKA after the paramedian and the subvatus approaches in 40 patients with osteoarthitis. Patients were randomised to the two groups and were evaluated by an independent observer blinded to the approach used. The two groups were compared as regards function (range of motion, quadriceps lag, quadriceps power); functional outcomes (Hospital for Special Surgery scores); patellofemoral alignment (Patellar tilt); and operative time, blood loss and hospital stay.
There was a statistically significance difference between the two groups as regards quadriceps power and lag in the first post-operative week. The subvastus group performed better than the paramedian group. The range of motion was also better in the subvastus group, though this difference was not statistically significant. The subvastus approach avoids the painful inhibitory arc of the quadriceps and allows for better and rapid rehabilitation in the early post-opertaive phase.
There were fewer lateral retinacular releases in the subvastus group. The presence of an intact extensor mechanism allows for more accurate assesment of the patellofemoral alignment intraoperatively. The patello-femoral alignment readings were better in the subvastus group. The subvastus approach does not interfere with the vascular supply of the patella.
The patients operated by the subvatus group were discarged from hospitals early.
The abstracts were prepared by Professor Jegan Krishnan. Correspondence should be addressed to him at the Flinders Medical Centre, Bedford Park 5047, Australia.
