Tendon Healing in Bone Tunnel after Human Anterior Cruciate Ligament Reconstruction: A Systematic Review of Histological Results

Abstract

Most studies concerning to tendon healing and incorporation into bone are mainly based on animal studies due to the invasive nature of the biopsy procedure. The evidence considering tendon graft healing to bone in humans is limited in several case series or case reports, and therefore, it is difficult to understand the healing process. A computerized search using relevant search terms was performed in the PubMed, EMBASE, Scopus, and Cochrane Library databases, as well as a manual search of reference lists. Searches were limited to studies that investigated tendon graft healing to bone by histologic examination after anterior cruciate ligament (ACL) reconstruction with hamstring. Ten studies were determined to be eligible for this systematic review. Thirty-seven cases were extracted from the included studies. Most studies showed that a fibrovascular interface would form at the tendon-bone interface at the early stage and a fibrous indirect interface with Sharpey-like fibers would be expected at the later stage. Cartilage-like tissue at tendon graft-bone interface was reported in three studies. Tendon graft failed to integrate with the surrounding bone in 10 of the 37 cases. Unexpectedly, suspensory type of fixation was used for the above failure cases. An indirect type of insertion with Sharpey-like fibers at tendon-bone interface could be expected after ACL reconstruction with hamstring. Regional cartilage-like tissue may form at tendon-bone interface occasionally. The underlying tendon-to-bone healing process is far from understood in the human hamstring ACL reconstruction. Further human studies are highly needed to understand tendon graft healing in bone tunnel after hamstring ACL reconstruction.

Recombinant Human Bone Morphogenetic Proteins-4 Enhanced the Tendon-to-bone Attachment Healing in a Murine Model of Rotator Cuff Tear: A Randomized Controlled Trial

“…In the BMP-4 and control group, there were some cartilage-like cells in the attachment zone, which was rare in the noggin specimens. The mean cell density in the TBA was lower in the BMP-4 groups (5425 ± 683 cells/mm 2…”

“…Tendon-to-bone attachment (TBA) transfers the force from muscles to bone during body movement, and the structure comprises four distinct yet continuous zones: tendon, nonmineralized brocartilage, mineralized brocartilage, and bone [1][2][3][4]. TBA injuries are common clinical dilemmas, such as rotator cuff tear.…”

Double-bundle Anatomic Anterior Cruciate Ligament Reconstruction Using Hamstring-bone Graft: a Long-term Follow Up

“…The suspensory fixation of hamstring tendon far from the tunnel aperture did not compress the tendon graft along the tunnel's length as fixation with an interference screw. In addition, this technique may also allow the ingrowth of blood vessels along the entire length of the tendon graft [29]. The study [30], explored the tendon-to-bone healing differences between interference screw versus EndoButton, indicating that fixation with interference screw led to an indirect ligamentous insertion and fixation with EndoButton led to viability of the graft tendon healing in the bone tunnel.…”

ACL Reconstruction with Augmentation: a Scoping Review

“…Osteointegration and graft maturation of hamstring autograft can be divided into four phases: the inflammatory phase, proliferative phase, matrix synthesis, and matrix remodeling (occurring around the 10-month post-operative) [25,26]. A 2015 systematic review identified six studies measuring graft maturation using MRI.…”