Roentgenographic and magnetic resonance imaging of anterior cruciate reconstruction using a patellar tendon graft--correlations with physical findings

Abstract

The purpose of this study was to evaluate the influence of the graft positioning on the clinical outcome and magnetic resonance imaging (MRI) signal of the graft following anterior cruciate ligament (ACL) reconstruction using the central one-third of the patellar tendon. Twenty-two patients with a chronic anterior instability underwent a modified Marshall-MacIntosh procedure, while 27 with a subacute torn ACL had an ACL reconstruction using a free bone-patellar tendon-bone graft. The patients were retrospectively reviewed with a 1.8-year average follow-up (1-3 years). The clinical result was evaluated through the comparative range of motion and the residual laxity as measured with the KT 1,000 arthrometer. The roentgenographic analysis was performed from anteroposterior (AP) and mediolateral (ML) views, made first on one-leg standing with the knee at 30 degrees of flexion, and secondly at "zero" extension with active quadriceps contraction. Lines were drawn to visualise the location of the tibial and femoral tunnels in relation to the tibial plateaus and the intercondylar roof represented by Blumensaat's line. The analysis of the lateral MRI views of the graft allowed discrimination between homogenous and heterogenous graft signals. On lateral roentgenograms of normal knees, it was found that Blumensaat's line crossed the surface of the medial tibial plateau at 30% +/- 9% of its sagittal width (20%-40% range), demonstrating the variability of intercondylar roof inclination. The range of motion was normal in 34 patients (group I), 9 patients had a flexion deficit (group II), and 6 exhibited an extension deficit (group III). The residual laxity was similar in each group (P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)