Dados do Trabalho

Título

Biological augmentation of graft healing with Bone Marrow Aspirated Concentrated in anterior cruciate ligament reconstruction

Introdução e Objetivo

The native ACL inserts to bone through a direct fibrocartilaginous enthesis, which is characterized by a four-zone morphological structure with gradual transition from tendon to cartilage to mineralized cartilage to bone. Following ACLR the graft heals with na indirect enthesis formed of biomechanically inferior fibrovascular scar tissue.14 As a result, research is ongoing investigating interventions that can biologically augment graft healing after ACLR, and which may facilitate Early aggressive rehabilitation and a faster return to physical activity.

Casuística e Método

Bone marrow was harvested from the anterior iliac crest with the syringe, in steps of 2–3 ml a time until a total of 30 ml of bone marrow had been aspirated. After each harvesting step, the syringe was disconnected and balanced in order to prevent coagulation of the marrow, and the needle was repositioned in the marrow space. Heparin (1,000 units per ml) was used as anticoagulant. The syringe used to Harvest the bone marrow was rinsed with the heparin solution, as was the tube and the bone marrow needle. The harvested bone marrow was centrifuged for 15 min at 3,200 RPM, and 3 ml of marrow stem cells concentrate were obtained. The concentrate contains a number of stem cells six times above the baseline.

Resultados

Harvest of the tendons of the semitendinosus and gracilis (STG) muscles is preferentially performed in the injured limb. For patients in whom these grafts were used in the primary reconstruction, the grafts are harvested from the contralateral limb. The STG grafts are folded to form a single quadruple graft. The quadruple graft surrounded by a collagen membrane (AMIC), leaving only 2 cm of proximal and distal graft without membrane coverage, then a suture with monocryl plus 4.0 (Ethicon) is made in the membrane around the graft, creating a kind of pouch wrapped around the having what allows injected between the membrane and the graft the bone marrow.
The graft is pulled through the femoral tunnel and passed through the tibial tunnel with the aid of a No. 5.0 Ethibond thread (Ethicon). The single portion of the graft is passed freely through the tibial and femoral tunnels until the another graft portion occupies both tunnels. The graft is then pulled, and an interference screw (Biosure; Smith & Nephew) is fixed to the femur.
The next step is to fix the inferior end of the quadruple graft to the tibia after pre-tensioning. Fixation is performed with the graft tensioned and the knee in total extension and after performance of the posterior drawer maneuver.
The next step is the injection of the bone marrow aspirate concentrate into the previously prepared collagen membrane. It is performed with the aid of an 18G needle and a 20 ml syringe, so that all aspirates are evenly distributed around the intra-articular portion of the tendons.

Discussão

As injury to the ACL is common, there are studies in the literature regarding the reconstruction’s main challenges, such as the tendon-bone healing and how this process can be enhanced and optimized. Hao et al. studies on stem cell therapy show the effects of tendon-bone healing with a wide variety of stem cell types, such as bone marrow-derived mesenchymal stem cells (BMSCs), synovial mesenchymal stem cells (sMSCs) and stem cells derived from ACL tissues, with a highlight to the sMSCs that showed and enhancement of the tendon-bone healing by accelerating the formation of fibrous structure, despite not meeting the goal to regenerate a normal ACL insertion site. The literature also mentions that the coating technique used in the Bio ACL procedure enhances graft-tunnel interface healing of artificial grafts. Distinct types of coatings are mentioned such as chitin, bioglass, gelatin and hyaluronic acid, polystyrene sodium sulfonate and collagen matrix.

Conclusão

The Bio ACL technique is one step further to a completer and more ideal ACLR