Long-term Comparison of Semitendinosus and Gracilis Tendon Versus Patellar Tendon Autografts for Anterior Cruciate Ligament Reconstruction: A 17-Year Follow-up of a Randomized Controlled Trial

Abstract

Background: Short-term and mid-term differences between hamstring and patellar tendon autografts for anterior cruciate ligament (ACL) reconstruction are well documented. Systematic reviews highlight the lack of long-term results between the two grafts. Hypothesis: Seventeen years after ACL reconstruction, no difference will be found in functional outcome, quality of life, and graft failure between patients with patellar tendon (PT) or semitendinosus and gracilis tendon (STG) autografts; however, a significant difference will be seen in the prevalence of osteoarthritis. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: Sixty-four patients were included in this prospective study (32 in each group). A single surgeon performed primary ACL reconstruction in alternating sequence. Forty-eight patients (24 in each group) were evaluated 17 years after ACL reconstruction: A clinical assessment was made based on the International Knee Documentation Committee (IKDC) form, instrumented laxity was measured with KT-1000 arthrometer, and radiography of the operated knee was conducted and assessed for degenerative disease. The Lysholm questionnaire and the Short Form–36 version 2 questionnaire were filled out by the patients. Results: At the 17-year follow-up, no statistically significant differences were seen with respect to graft failure (2 reruptures in the semitendinosus and gracilis tendon [STG] group [6.3%] and 3 reruptures in the PT group [9.4%]) and functional outcome. Increased instrumented laxity (>3 mm) measured with KT-1000 arthrometer was seen in significantly more patients in the STG group (8 in the STG group compared with 2 in the PT group; P = .03) with a mean side-to-side difference of 2.17 ± 1.86 mm in the STG group compared with 1.33 ± 1.93 mm in the PT group. A significant difference was found in frequency of knee osteoarthritis (OA)—100% in the PT group compared with 71% in the STG group ( P = .004). Patients in the PT group tended to have higher grade OA according to the IKDC grading system, with an average grade of 1.46 in the PT group compared with 1 in the STG group ( P = .055). The degenerative changes in the PT group were more common in the medial and patellofemoral compartments ( P = .003 and P = .04, respectively). Conclusion: Both autografts provided good to excellent subjective outcomes. No significant differences were noted in graft failure and clinical instability. However, significantly more patients in the STG group had increased instrumented anteroposterior translation measured with KT-1000 arthrometer, and there was a greater prevalence of knee OA at 17 years after surgery in the PT group.