Anterior cruciate ligament patellar tendon reconstruction: it is probably better to leave the tendon defect open!

Abstract

The purpose of our prospective study was to establish whether or not in anterior cruciate ligament (ACL) patellar tendon reconstruction the tendon defect has to be closed. In 50 consecutive ACL patellar tendon reconstructions, the tendon defect was randomly closed (group I) or left open (group II). The following data were recorded from all patients on the 4th and 14th days post operation: range of motion (ROM), pain at rest, pain and validity at isometric contraction, ability of bent leg raising (at 4th day) and straight leg raising (at 14th day). All the patients underwent ultrasonographic examination after 3 months and X-ray scanning at 6 months post operation. Forty patients underwent a CT-scan examination at 6 months. Thirty patients underwent isokinetic testing between 10 and 12 months post operation. Evaluating the immediate post operation data, no statistically significant differences emerged between the two groups. Ultrasonography showed in 68% of the knees of group I (defect closed) a thickened patellar tendon (PT), while in 60% of group II it was of normal thickness. No patients of either group developed patella infera by X-ray evaluation 6 months post operation. CT scans at 6 months showed that 100% of the knees of group I had a thickened PT in toto (nearly twice as thick as normal). Scar tissue was present not only in its central third but also in more than half of the cases in the medial and lateral third. In group II 75% of the patients had a normal thickness PT and 25% presented with only a minimal thickening. Scar tissue was distinguished only at its central third. Some 32% and 36% of the patients of group I and II, respectively, developed patellar irritability between the 5th and 8th month post operation. Isokinetic tests performed between the 10th and 12th months showed that the quadriceps deficit was slightly less in group II than in group I. Our study did not show very important clinical differences between the two groups but revealed that if the tendon defect is closed, an exuberant scar process arises involving the entire PT. This could mean, as reported in the literature, a high reduction in the biomechanical properties of the PT. For this reason it is “probably” better to leave the defect open.