Nanohydroxyapatite-based bone graft substitute in tunnel enlargement after ACL surgery: RMN study.

Abstract

A successful anterior cruciate ligament reconstruction (ACL) requires solid healing of the tendon graft in the bone tunnel. New biological strategies have already been proposed with the aim of improving ACL graft healing and therefore allowing a faster rehabilitative program. The aim of this prospective study was to clinically and radiologically evaluate the efficacy of nanohydroxyapatite bone-base grafts in facilitating bone-tendon incorporation after ACL reconstruction with hamstrings (HS). As far as we know, this is the first study that has tried to asses the efficacy of such a type of bone substitute on human beings. 40 male patients with chronic ACL rupture who underwent surgical reconstruction with 4-strand semitendinosus and gracilis tendon autograft via a single-bundle technique. Patients were randomly assigned to enter group A (20 patients, nanohydroxyapatite group) or group B (20 patients, control group). Preoperative and postoperative clinical evaluation was always performed, in a blinded way, assessing the Lachman and Pivot-shift tests and range of motion (ROM) of the affected knee. The Lysholm knee score, Tegner activity level, subjective and objective International Knee Documentation Committee (IKDC) forms, and 30 lb KT-1000 arthrometer evaluations. Patients underwent a magnetic resonance imaging (MRI) exam at 30, 90 and 180 days after surgery by the same musculoskeletal radiologist in a blinded way. As for the clinical evaluation, Lysholm, Tegner, IKDC scales, and KT-1000 arthrometer results did not show any significant difference between the two groups. Radiological data show a tendency toward better results in regard to the graft strength signal, the graftbone interface, and bone edema remodeling process, these parameters show significant differences between the two groups only at the short or mid-term follow-ups, while they are never significant at the mid-to long-term follow-up. In conclusion the use of nanohydroxyapatite bone substitute does not provide significant clinical improvements in terms of better knee stability or patient satisfaction.