Novel Hybrid Hydroxyapatite Spacers Ensure Sufficient Bone Bonding in Cervical Laminoplasty

STUDY DESIGN: Prospective observational study. PURPOSE: This prospective analysis aimed to evaluate the efficacy and bone-bonding rate of hybrid hydroxyapatite (HA) spacers in expansive laminoplasty. OVERVIEW OF LITERATURE: Various types of spacers or plates have been developed for expansive laminoplasty. METHODS: Expansive open-door laminoplasty was performed in 146 patients with cervical myelopathy; 450 hybrid HA spacers and 41 autogenous bone spacers harvested from the spinous processes were grafted into the opened side of each lamina. The patients were followed up using computed tomography (CT), and their bone-bonding rates for hybrid HA and autogenous spacers, bone-fusion rates of the hinges of the laminae, and complications associated with the implants were then examined. RESULTS: Clinical symptoms significantly improved in all patients, and no major complications related to the procedure were noted. The hybrid HA spacers exhibited sufficient bone bonding on postoperative CT. The hinges completely fused in over 95% patients within 1 year of the procedure. Only 4 spacers (0.9%) developed lamina sinking, and most expanded laminae maintained their positions without sinking or floating throughout the follow-up period. CONCLUSIONS: Hybrid HA spacers contributed to high bone-fusion rates of the spacers and hinges of the laminae, and no complications were associated with their use. Cervical laminoplasty with these spacers is safe and simple, and it yields sufficient fixation strength while ensuring sufficient bone bonding during the immediate postoperative period.

Rotational Acetabular Osteotomy

Hip dysplasia is the most common cause of secondary osteoarthritis (OA). To prevent the early onset of secondary OA, Nishio's transposition osteotomy, Steel's triple osteotomy, Eppright's dial osteotomy, Wagner's spherical acetabular osteotomy, Tagawa's rotational acetabular osteotomy (RAO), and Ganz' periacetabular osteotomy (PAO) have been proposed. PAO and RAO are now commonly used in surgical treatment of symptomatic acetabular dysplasia in Europe, North America, and Asia. The aim of this paper is to present the followings: the patient selection criteria for RAO; the surgical technique of RAO; the long-term outcome of RAO; and the future perspectives.

Clinical Results of Transplantation of Tissue-Engineered Cartilage and Future Direction of Cartilage Repair: Novel Approach with Minimally Invasive Procedure

Articular cartilage has very limited potential to spontaneously heal, because it lacks vessels and is isolated from systemic regulation. No treatment has repaired the defects with long-lasting hyaline cartilage. Recently, a regenerative medicine by a tissue-engineering technique for cartilage repair has been given much attention in the orthopaedic field. In 1994, Brittberg et al. introduced a new technology in which chondrocytes expanded in monolayer culture were transplanted into the cartilage defect of the knee. As a second generation of chondrocyte transplantation, we have been performing transplantation of tissue-engineered cartilage made ex vivo for the treatment of osteochondral defects of the joints since 1996. This signifies a concept shift from cell transplantation to tissue transplantation made ex vivo using tissue-engineering technique. We have reported good clinical results with this surgical treatment. However, extensive basic research is vital to achieve better clinical results with this tissue-engineering technique. I would like to describe our recent research using a minimally invasive tissue-engineering technique to promote cartilage regeneration.