Reverse Drilling Technique in Improving Outcomes After Arthroscopic Anterior Cruciate Ligament Reconstruction

Compaction technique can create a denser bone tunnel wall with more cancellous bone autografting in situ by sequentially compressing cancellous bone trabeculae to bone tunnel walls, in contrast to conventional extraction reaming by which an enlarged gap is created and initial direct integration is limited between implants and bone, as chunks of cancellous bone are torn out, thereby being removed outside the tunnel. Biologically, a compaction technique was reported to increase the bone volume around grafts and provide a larger area of bone-to-graft contact for bone integration because of the spring-back effect. Mechanically, compaction of the bone graft into the femoral tunnel was reported to significantly increase stiffness of the grafts. Reverse drilling (RD) can compress peritunnel bone at the time of bone tunnel preparation to make the tunnel wall denser and smoother in comparison with extraction drilling (ED), reverse drilling yields the same compaction effect as the compaction technique. Bone dust (BD) is commonly defined as pieces of bone produced by a power-driven tool. It is universally accepted that bone debris more than 200 mm in particle size is classified as particulate bone and that bone debris no more than 200 mm is classified as BD. When applied for ACLR, BD could fully utilize the advantages of an autologous bone graft while avoiding invasive and traumatic bone harvesting procedures, as bone tunnel preparation is accompanied by the production of a considerable amount of BD. Therefore, BD grafting is promising for improving tendon-bone healing with safety and simplification. We refer to the technique of retaining BD in the bone tunnel after RD as the reverse drilling technique. We hyposize that reverse drilling technique can improve outcomes after arthroscopic anterior cruciate ligament reconstruction by improving peritunnel bone and preventing bone tunnel enlargement.