MRI AT ONE AND FIVE YEARS IN 62 ANTERIOR CRUCIATE LIGAMENT GRAFTS WITH TIBIAL FIXATION WITH A RESORBABLE SCREW

Abstract

Purpose: The purpose of this study was to analyse the clinical and MRI results of anterior cruciate ligament (ACL) grafts using the patellar tendon with a tibial fixation by th resorbable interference screw PLA 98 (Phusis(r)).

Material and methods: ACL grafts were performed in 182 patients between 1994 and 1997. A unique graft was used in 85 cases (Kenneth Jones), and association with Lemaire plasty in 97. The tibial fixation was achieved with the resorbable screw in all cases. Clinical and radiological data were recorded before surgery, and at one and five years. Among the 110 patients with an MRI at one year, 62 also had an MRI control at five years (57%). The antero-posteior and mediolateral tibial position was evaluated on the horizontal slices. We defined a method for evaluating the femoral position on the horizontal MRI slices. The aspect of the graft was analysed at one and five years.

Results: There were three failures (Trillat-Lachmann test). Mean residual differential laxity was 2.6 mm (Telos). At five years, 92% of patients practiced sports at a moderate or intensive level. The tibial position was good and highly reproducible (SD=0.06). Five femoral positions were not satisfactory but were not related with failure. All screws were resorbed at five years. There were two bone reactions at one year, with no relation with screw absorption (one contusion and one reflex dystrophy). At one year, the MRI with gadolinium injection visualised peripheral enhancement of the graft. At five years three transplants appeared heterogeneous, corresponding to three ruptures. Segmentary heterogenic aspects were not found to have any pathological significance.

Discussion: Evaluation of the femoral position is difficult on the MRI sagittal views. Our analysis method based on horizontal slices allowed reliable reproducible analysis. Analysis of the graft should take into consideration the time since surgery and the sequence used. There was no problem with fixation or screw absorption.

Conclusion: MRI follow-up of ACL grafts enables an analysis of the transplant positions, to follow the evolution of the graft, and to confirm the reliability and safety of the resorbable screw fixation.