2565. MRI Patterns of ACL Repair with Internal Brace Augmentation
Authors * Denotes Presenting Author
  1. Jon Olson *; Medstar Washington Hospital Center; United States Air Force
  2. Jordan Gold; Medstar Washington Hospital Center
  3. Wiemi Douoguih; Medstar Georgetown University Hospital; Medstar Washington Hospital Center
  4. Stephen Savioli; Medstar Washington Hospital Center; United States Army
  5. James Jelinek; Medstar Washington Hospital Center
  6. Ian Amber; Medstar Georgetown University Hospital
  7. Mark Murphey; ACR Institute of Radiologic Pathology
Characterize MRI findings in a patient cohort with proximal ACL tears (Sherman type 1 or 2) approximately 1 year following suture-augmented repair.

Materials and Methods:
Postoperative MRI exams of 23 subjects were obtained at approximately 1 year following ACL repair with suture augmentation. MR studies were retrospectively reviewed by two musculoskeletal (MSK) radiologists and one MSK fellow. Ligamentous repair was assessed for integrity (intact or not), intrinsic signal (homogeneous or multilaminar), signal intensity (low, intermediate, or high), ACL width (sagittal and coronal dimensions), femoral and tibial tract widths, and arthrofibrosis (present or not). Secondary signs of recent injury such as bone contusions or coexisting meniscal tears were also recorded, as well as the patient’s age and gender.

ACL ligament repair was identified and intact in 22/23 subjects. Of these, 12 demonstrated a multilaminar appearance of which 7/12, 4/12, and 1/12 showed low, intermediate, and high signal intensity, respectively. The remaining 10 intact repairs revealed a homogenous appearance, with 7/10, 3/10, and 0/10 showing low, intermediate, and high signal intensity, respectively. Average ACL width was 8.6 and 8.1 mm in sagittal and coronal planes, respectively. Average femoral and tibial tract widths were 3.3 and 3.1 mm, respectively. Arthrofibrosis was identified in one patient. There were age-indeterminate, coexisting meniscal tears in 5/23 patients. The one patient with failed repair revealed ACL disruption and pivot-shift bone contusions.

Although ACL reconstruction techniques remain the gold standard, there is growing acceptance for primary repair techniques as a viable alternative for proximal tears. MSK radiologists need to be aware of the variable imaging appearance of the ACL following suture augmented repair. Our data suggest that despite nonuniform appearance and variable signal intensity, ACL repair integrity or disruption can be accurately assessed on MRI. This initial review requires subsequent confirmatory studies and determination of factors that contribute to potential repair, failure, or additional complications.