Clinical Orthopaedics and Related Research ®

A Publication of The Association of Bone and Joint Surgeons ®

Basic Research 173 articles


Low-intensity Pulsed Ultrasound Enhances Bone Repair in a Rabbit Model of Steroid-associated Osteonecrosis

Hanxiao Zhu MD, Xunzi Cai MD, Tiao Lin MD, Zhongli Shi MD, Shigui Yan MD

Steroids are a leading cause of femoral head osteonecrosis. Currently there are no medications available to prevent and/or treat steroid-associated osteonecrosis. Low-intensity pulsed ultrasound (LIPUS) was approved by the FDA for treating delayed union of bone fractures. Some studies have reported that LIPUS can enhance bone formation and local blood flow in an animal model of fracture healing. However, whether the effect of osteogenesis and neovascularization by LIPUS can enhance the repair progress in steroid-associated osteonecrosis is unknown.

Does Cyclic Stress Play a Role in Highly Crosslinked Polyethylene Oxidation?

Francisco Medel PhD, Steven Kurtz PhD, Daniel MacDonald MS, Francisco Javier Pascual MS, José Antonio Puértolas PhD

Minimizing the impact of oxidation on ultrahigh-molecular-weight polyethylene components is important for preserving their mechanical integrity while in vivo. Among the strategies to reduce oxidation in modern first-generation highly crosslinked polyethylenes (HXLPEs), postirradiation remelting was considered to afford the greatest stability. However, recent studies have documented measurable oxidation in remelted HXLPE retrievals. Biologic prooxidants and physiologic loading have been proposed as potential mechanisms.

Spectroscopic and Chromatographic Quantification of an Antioxidant-stabilized Ultrahigh-molecular-weight Polyethylene

Venkat S. Narayan PhD

The oxidative stability of various antioxidant-containing ultrahigh-molecular-weight polyethylene (UHMWPE) formulations has been widely reported. Depending on which specific antioxidant is used, the process by which it is incorporated into UHMWPE, and the amount of the antioxidant incorporated, there could be substantial differences in the material and toxicological properties of the UHMWPE formulation. Pentaerythritol tetrakis (3-[3,5-di tertiary butyl-4-hydroxyphenyl] propionate) (PBHP) has been extensively used as an efficient antioxidant in various applications. However, it has not thus far been used to stabilize UHMWPE in orthopaedic implants. It is therefore important to characterize and verify the concentration and homogeneity of distribution of PBHP in the composition, the chemical consequence of exposure of the antioxidant to gamma irradiation, and to assess the toxicological risk of use by the identification and quantification of leachables before the use of PBHP-containing UHMWPE in implantable devices.

Cationic Nanogel-mediated Runx2 and Osterix siRNA Delivery Decreases Mineralization in MC3T3 Cells

Arun R. Shrivats PhD, Eric Hsu PhD, Saadyah Averick PhD, Molly Klimak, April C. S. Watt MS, Marlene DeMaio MD, Krzysztof Matyjaszewski PhD, Jeffrey O. Hollinger DDS, PhD

Heterotopic ossification (HO) may occur after musculoskeletal trauma, traumatic brain injury, and total joint arthroplasty. As such, HO is a compelling clinical concern in both military and civilian medicine. A possible etiology of HO involves dysregulated signals in the bone morphogenetic protein osteogenic cascade. Contemporary treatment options for HO (ie, nonsteroidal antiinflammatory drugs and radiation therapy) have adverse effects associated with their use and are not biologically engineered to abrogate the molecular mechanisms that govern osteogenic differentiation.

Do Crosslinking and Vitamin E Stabilization Influence Microbial Adhesions on UHMWPE-based Biomaterials?

Giuliana Banche PhD, Pierangiola Bracco PhD, Valeria Allizond PhD, Alessandro Bistolfi MD, Michele Boffano MD, Andrea Cimino MD, Elena Maria Brach del Prever MD, Anna Maria Cuffini PhD

Microorganism adhesion on polyethylene for total joint arthroplasty is a concern. Many studies have focused on vitamin E-stabilized ultrahigh-molecular-weight polyethylene (UHMWPE), whereas first-generation, highly crosslinked UHMWPE, which is the most commonly used in clinical practice, has been scarcely evaluated.

rhPDGF-BB Promotes Early Healing in a Rat Rotator Cuff Repair Model

David Kovacevic MD, Lawrence V. Gulotta MD, Liang Ying DVM, John R. Ehteshami MD, Xiang-Hua Deng MD, Scott A. Rodeo MD

Tendon-bone healing after rotator cuff repair occurs by fibrovascular scar tissue formation, which is weaker than a normal tendon-bone insertion site. Growth factors play a role in tissue formation and have the potential to augment soft tissue healing in the perioperative period.

Multidirectional Wear and Impact-to-wear Tests of Phospholipid-polymer-grafted and Vitamin E-blended Crosslinked Polyethylene: A Pilot Study

Masayuki Kyomoto PhD, Toru Moro MD, Yoshio Takatori MD, Sakae Tanaka MD, Kazuhiko Ishihara PhD

Modifying the surface and substrate of a crosslinked polyethylene (CLPE) liner may be beneficial for high wear resistance as well as high oxidative stability and excellent mechanical properties, which would be useful in contributing to the long-term performance of orthopaedic bearings. A grafted poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) layer on a vitamin E-blended crosslinked PE (HD-CLPE[VE]) surface may provide hydrophilicity and lubricity without compromising the oxidative stability or mechanical properties.

Is There Material Loss at the Backside Taper in Modular CoCr Acetabular Liners?

Matthias T. Agne, Richard J. Underwood PhD, Sevi B. Kocagoz BS, Daniel W. MacDonald MS, Judd S. Day PhD, Javad Parvizi MD, Matthew J. Kraay MS, MD, Michael A. Mont MD, Gregg R. Klein MD, Harold E. Cates MD, Steven M. Kurtz PhD

Metal wear and corrosion products generated by hip replacements have been linked to adverse local tissue reactions. Recent investigations of the stem/head taper junction have identified this modular interface as another possible source of metal debris; however, little is known regarding other modular metallic interfaces, their ability to produce metal debris, and possibly to provide insight in the mechanisms that produce metal debris.

Can High-friction Intraannular Material Increase Screw Pullout Strength in Osteoporotic Bone?

Daniel Bronsnick MD, Ryan E. Harold BS, Ari Youderian MD, Giovanni Solitro PhD, Farid Amirouche PhD, Benjamin Goldberg MD

Osteoporotic bone brings unique challenges to orthopaedic surgery, including a higher likelihood of problematic screw stripping in cancellous bone. Currently, there are limited options to satisfactorily repair stripped screws. Additionally, nonstripped screws hold with less purchase in osteoporotic bone.

A Comparison of the Efficacy of Various Antioxidants on the Oxidative Stability of Irradiated Polyethylene

Natalie Hope MBBS, MA(Cantab), MRCS, Anuj Bellare PhD

Ultrahigh-molecular-weight polyethylene (UHMWPE) is subjected to radiation crosslinking to form highly crosslinked polyethylene (HXLPE), which has improved wear resistance. First-generation HXLPE was subjected to thermal treatment to reduce or quench free radicals that can induce long-term oxidative degeneration. Most recently, antioxidants have been added to HXLPE to induce oxidative resistance rather than by thermal treatment. However, antioxidants can interfere with the efficiency of radiation crosslinking.