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Despite substantial attention given to the development of osteoregenerative biomaterials, severe deficiencies remain in current products. These limitations include an inability to adequately, rapidly, and reproducibly regenerate new bone; high costs and limited manufacturing capacity; and lack of surgical ease of handling. To address these shortcomings, we generated a new, synthetic osteoregenerative biomaterial, hyperelastic "bone" (HB). HB, which is composed of 90 weight % (wt %) hydroxyapatite and 10 wt % polycaprolactone or poly(lactic-co-glycolic acid), could be rapidly three-dimensionally (3D) printed (up to 275 cm(3)/hour) from room temperature extruded liquid inks. The resulting 3D-printed HB exhibited elastic mechanical properties (~32 to 67% strain to failure, ~4 to 11 MPa elastic modulus), was highly absorbent (50% material porosity), supported cell viability and proliferation, and induced osteogenic differentiation of bone marrow-derived human mesenchymal stem cells cultured in vitro over 4 weeks without any osteo-inducing factors in the medium. We evaluated HB in vivo in a mouse subcutaneous implant model for material biocompatibility (7 and 35 days), in a rat posterolateral spinal fusion model for new bone formation (8 weeks), and in a large, non-human primate calvarial defect case study (4 weeks). HB did not elicit a negative immune response, became vascularized, quickly integrated with surrounding tissues, and rapidly ossified and supported new bone growth without the need for added biological factors.

Peptide amphiphile (PA) nanofibers formed by self-assembly can be customized for specific applications in regenerative medicine through the use of molecules that display bioactive signals on their surfaces. We report here on the use of PA nanofibers with binding affinity for the bone promoting growth factor BMP-2 to create a gel scaffold for osteogenesis. With the objective of reducing the amount of BMP-2 used clinically for successful arthrodesis in the spine, we used amounts of growth factor incorporated in the scaffolds that are 10 to 100 times lower than that those used clinically in collagen scaffolds. The efficacy of the bioactive PA system to promote BMP-2-induced osteogenesis in vivo was investigated in a rat posterolateral lumbar intertransverse spinal fusion model. PA nanofiber gels displaying BMP-2-binding segments exhibited superior spinal fusion rates relative to controls, effectively decreasing the required therapeutic dose of BMP-2 by ten-fold. Interestingly, a 42% fusion rate was observed for gels containing the bioactive nanofibers without the use of exogenous BMP-2, suggesting the ability of the nanofiber to recruit endogenous growth factor. Results obtained here demonstrate that bioactive biomaterials with capacity to bind specific growth factors by design are great targets for regenerative medicine.

NBA players undergoing Achilles tendon rupture repair or arthroscopic knee surgery had significantly worse performance postoperatively compared with other orthopaedic procedures.

The data indicate that NFL athletes fare the worst after ACLR with the lowest survival rate, shortest postoperative career length, and sustained decreases in performance. NHL athletes fare the best with the highest rates of RTP, highest survival rates, longest postoperative career lengths, and no significant changes in performance. The unique physical demand that each sport requires is likely one of the explanations for these differences in outcomes.

No abstract

A direct comparison of interbody implants demonstrates significant and measurable differences in biomechanical, µ-CT, and histologic performance in an ovine model. The 3D-printed porous titanium interbody cage resulted in statistically significant reductions in ROM, increases in the bone ingrowth profile, as well as average construct stiffness compared with PEEK and PSP.

Purpose Spine-related research has evolved dramatically during the last century. Significant contributions have been made by thousands of authors. A citation rank list has historically been used within a particular field to measure the importance of an article. The purpose of this article is to report on the 100 most cited articles in the field of spine. Methods Science Citation Index Expanded was searched for citations in 27 different journals (as of 30 November 2010) chosen based on the relevance for all cited spine publications. The top 100 most cited articles were identified. Important information such as journal, date, country of origin, author, subspecialty, and level of evidence (for clinical research) were compiled. Results The top 100 publications ranged from 1,695 to 240 citations. Fifty-three articles were of the lumbar, 17 were of the thoracolumbar, and 15 of the cervical spine. Eighty-one of the articles were clinical and 19 were basic science in nature. Level of evidence varied for the clinical papers, however, was most commonly level IV (34 of 81 articles). Notably, the 1990-1999 decade was the most productive period with 43 of the top 100 articles published during this time.Conclusions Identification of the most cited articles within the field of spine recognizes some of the most important contributions in the peer-reviewed literature. Current investigators may utilize the aspects of their work to guide and direct future spine-related research.