2015 ISAKOS Biennial Congress ePoster #1344
MRI Examination of Donor Site Morphology in Patients with ACL Reconstruction Using Bone-Patellar Tendon-Bone Autograft
Patrick W. Kane, MD, Lewes, DE UNITED STATES
William Morrison, MD, Philadelphia, PA UNITED STATES
Jocelyn M. Wascher, BA
Matthew Salminen, MS, Philadelphia, PA UNITED STATES
Kevin Henrichsen, BS, Philadelphia, PA UNITED STATES
Christopher C. Dodson, MD, Philadelphia, PA UNITED STATES
Michael G. Ciccotti, MD, Philadelphia, PA UNITED STATES
Steven B. Cohen, MD, Media, PA UNITED STATES
The Rothman Institute of Orthopaedics at Thomas Jefferson University, Philadelphia, PA, USA
FDA Status Not Applicable
Summary: Radiographic evaluation of donor site morbidity two years post bone-patellar-bone anterior cruciate ligament (ACL) autograft found that while the patellar tendon and surrounding soft tissues recover well, the bony donor sites exhibit a higher percentage of edema and more modest regeneration.
Objectives: Anterior Cruciate Ligament (ACL) ruptures are one of the most common sports injuries, with over 100,000 ACL reconstructions performed in the United States annually. Although many different graft choices exist, in recent years bone-patellar tendon-bone (BTB) autografts have become the graft of choice for ACL reconstruction, particularly in the young athlete. While effective in reconstructing the ACL, donor site morbidity with the use of BTB autograft remains a concern. The primary objective of this study is to evaluate the MRI appearance of the BTB autograft site in patients returning for radiographic evaluation following ACL reconstruction.
All knee MRIs performed on patients with a history of previous ACL reconstruction at our tertiary institution between the years of 2007 and 2012 were reviewed. Only patients with BTB autografts were included for further analysis. A fellowship trained, musculoskeletal radiologist reviewed the BTB donor site of all eligible MRI’s, concentrating on patellar tendon, inferior patella, and tibial tubercle morphology. Factors analyzed include: patellar tendon gap width, cross sectional area of the patellar tendon, presence or absence of edema at both the donor site and also the surrounding soft tissues, and the degree of bone proliferation and regeneration at both the tibial tubercle and inferior patella.
The average residual patellar tendon gap was found to be less than 1.6 mm. The average cross sectional area of remaining tendon was 166 mm2. When reviewing the soft tissues, 87% of patients had a normal appearance of the prepatellar soft tissues, 90% had a normal appearance of Hoffa’s fat pad, and over 89% had a normal appearing paratenon. When examining the bony donor sites of the BTB autograft, only 74% of patients had a normal appearance of the inferior pole of the patella or the tibial tubercle. Similarly, complete or nearly complete bony in-growth and regeneration of the inferior patellar pole and tibial tubercle were only found to be 45% and 36% respectively.
While Bone-Patellar Tendon-Bone autografts are an effective method of reconstructing the ACL, the long-term consequences and morbidity associated with their use remain a concern. Magnetic Resonance Imaging provides valuable insight into the appearance and morphology of the BTB autograft site following ACL reconstruction. The patellar tendon itself appears to recover well from harvesting with evidence of minimal residual gap and a low frequency of associated edema or scar formation in the surrounding soft tissues. The bony donor sites, however, appear to have a more limited recovery. The inferior pole of the patella and the tibial tubercle exhibit a higher percentage of edema and both areas showed modest bony regeneration. While these findings must be taken into clinical context, they are considerations when counseling patients on graft selection for ACL reconstruction.