Purpose: Anterior cruciate ligament reconstructions are becoming increasingly frequent, and MRI has been shown to be the best imaging modality for the non-invasive assessment of surgical outcome. Use of the quadriceps tendon as a biological replacement for injured cruciate ligament is a recent innovation. This study evaluated by MRI the results of anterior cruciate reconstruction in 27 consecutive patients who underwent arthroscopic reconstruction with homologous quadriceps tendon.
Material and methods: MRI was carried out on 27 patients who had undergone anterior cruciate ligament reconstruction with the middle third of the homolateral quadriceps tendon. The examinations were performed on two MRI units: a permanent 0.2-Tesla dedicated magnet (Artoscan, Esaote Italy) and whole-body 1.5-Tesla superconducting magnet (Signa, GE Medical Systems Milwaukee, Winsconsin USA). Axial, sagittal and coronal images were acquired with SE, GE and STIR fat suppression sequences. The examinations were performed 1, 3, and 6 months post-operatively in 16 patients, and 1 and 3 post-operatively in 11 patients. The same arthroscopic surgical technique was employed in all patients, with 20 cases of tibial mono-tunnel femoral semi-tunnel, and 7 cases with tibial bi-tunnel technique. All patients were assessed by arthrometric and clinical tests after surgery. Bioabsorbable interference screws were used for tibial fixation in all patients and metallic interference screws were used for femoral graft fixation in 8 patients.
Results: In all cases MRI correctly visualised the tunnel positions, the articular portion and the bone-portion of the graft inside the tibial and femoral tunnels. The absence of paramagnetic artefacts in the tibia allowed complete visualisation on the axial, sagittal and coronal MRI images with optimal spatial and contrast resolutions. In 6 cases, the presence of metal residues from the surgical cutter prevented correct evaluation of femoral tunnel content. No new graft or articular lesions were found. In 18/27 cases peri-focal marrow edema around the tibial tunnel had disappeared 3 months after surgery. The process of synovial incorporation was judged to be correct in all cases.
Discussion: The use of anterior cruciate ligament reconstruction with the quadriceps tendon is a important innovation given the size of the harvested material and the possibility of completely filling the osseous tunnels, without interposition of synovial proliferation or fluid collection between tendon and bone, as confirmed by MRI. Furthermore, the use of non-metallic screws allows MRI evaluation of tunnel content and oedema in the spongy bone around the tunnel. The study of the double tibial tunnel requires specific obliqueness in the coronal plane scans.
Conclusions: This arthroscopic technique for anterior cruciate ligament reconstruction allows thorough MRI evaluation of all portions of the transplant, and in particular those coursing within the tibia and femur. The absence of bone oedema around the tunnels and synovial proliferation within the tunnels may be predictive of faster healing and complete bone incorporation of the grafts.