MR imaging of anterior cruciate ligament reconstruction graft

OBJECTIVE. The objective was to determine the MR imaging findings that diff erentiate intact anterior cruciate ligament reconstruction graft, partial-t hickness tear, and full-thickness tear, using arthroscopy as the gold stand ard. MATERIALS AND METHODS. Sixteen consecutive MR imaging examinations were ret rospectively and independently evaluated by two musculoskeletal radiologist s fur primary signs (graft signal, orientation, fiber continuity, complete discontinuity, and thickness) and secondary signs (anterior tibial translat ion, uncovered posterior horn lateral meniscus, posterior cruciate ligament hyperbuckling, and abnormal posterior cruciate ligament line) of anterior cruciate ligament reconstruction graft tear in 15 patients with follow-up a rthroscopy. Results were compared with arthroscopy, and both receiver opera ting characteristic curves and kappa values for interobserver variability w ere calculated. RESULTS. Arthroscopy revealed four full-thickness graft tears, seven partia l-thickness tears, and five intact grafts. Of the primary signs, graft fibe r continuity in the coronal plane and 100% graft thickness in the sagittal or coronal plane were most valuable in excluding full-thickness tear Comple te discontinuous graft in the coronal plane also was valuable in diagnosis of full-thickness tear. Of the secondary signs, anterior tibial translation and uncovered posterior horn lateral meniscus assisted in differentiating graft tear (partial or full thickness) from intact graft. The other primary and secondary signs were less valuable. Kappa values were highest for graf t fiber continuity and graft discontinuity in the coronal plant. CONCLUSION. Full-thickness anterior cruciate ligament graft tear can be dif ferentiated from partial-thickness tear or intact graft by evaluating for g raft fiber continuity (coronal plane), complete graft discontinuity (corona l plane), and graft thickness (coronal or sagittal plane).