Perioteum-Enveloping Hamstring Tendon Graft for Anterior Gruciate Ligament Reconstruction-From Basic Research to Clincal Application

Fixation and incorporation of a tendon graft within the bone tunnel is a major concern when performing ligament reconstruction. Periosteum consists of multipotent stem cells, and has the potential to form osteogenic and chondrogenic tissues. The hypothesis that periosteum could enhance tendon-bone healing within the bone tunnel was studied in a rabbit model. Histological and biomechanical analyses were performed 4, 8, and 12 weeks after surgery. Serialhistological analysis of the tendon-bone interface showed that an interface fibrous layer formed by periosteum between the tendon and the bone. This layer became progressively intergrated within the tendon and bone surfaces during the healing process. At 4 weeks, the new cancellous bone lined the bone tunnel, which became interdigitated with interfacial fibrous tissue. At 8 weeks, there was progressive mineralization and maturation of the new bone growing into the interfacial fibrous layer. At 12 weeks, progressive collagen fiber-bone anchorage, maturation and organization developed and fibrocartilage formed between the tendon and bone. Biomechanical testing revealed higher maximal pull-out strength in the periostem-enveloped group at all time points, with a statistically significant difference at 8 and 12 weeks. The periosteum-treated limb had a higher interface strength-to-length ratio and significant increase between two groups at 8 weeks and 12 weeks. The histolofical and biomechanical studies demonstrated a superior process and stronger healing strength when periosteum was sutured on the tendon that transplanted within a bone tunnel. We applied this idea on the ACL reconstruction with hamstring tendon graft to enhance tendon-bone healing.