Clinical Orthopaedics and Related Research ®

A Publication of The Association of Bone and Joint Surgeons ®

Basic Research 173 articles


Differential Cytotoxicity of Corticosteroids on Human Mesenchymal Stem Cells

Cody C. Wyles BS, Matthew T. Houdek MD, Saranya P. Wyles BA, Eric R. Wagner MD, Atta Behfar MD, PhD, Rafael J. Sierra MD

Corticosteroids are a common, short-term, local antiinflammatory and analgesic for treating patients with musculoskeletal disorders. Studies have shown the deleterious effects of corticosteroids on chondrocytes, suggesting a potentiation of degenerative joint disease. Mesenchymal stem cells (MSCs) are the direct progenitors of chondrocytes and other musculoskeletal tissue. Additionally, they serve an important antiinflammatory role, which can combat the chronic inflammatory state that mediates degenerative joint disease. Little is known about how corticosteroids interact with this regenerative and reparative cell population.

Muscle Fibers are Injured at the Time of Acute and Chronic Rotator Cuff Repair

Max E. Davis BA, Patrick L. Stafford BS, Matthew J. Jergenson, Asheesh Bedi MD, Christopher L. Mendias PhD, ATC

Rotator cuff tears are a common source of shoulder pain and disability. Even after surgical repair, some patients continue to have reduced function and progression of fatty degeneration. Because patients with chronic cuff tears often experience muscle shortening, it is possible that repairing the tendon to its anatomic footprint induces a stretch-induced muscle injury that could contribute to failures of the repair and perhaps ongoing pain.

Natural Polyphenols Enhance Stability of Crosslinked UHMWPE for Joint Implants

Jie Shen MEng, Guorong Gao MEng, Xincai Liu PhD, Jun Fu PhD

Radiation-crosslinked UHMWPE has been used for joint implants since the 1990s. Postirradiation remelting enhances oxidative stability, but with some loss in strength and toughness. Vitamin E-stabilized crosslinked UHMWPE has shown improved strength and stability as compared with irradiated and remelted UHMWPE. With more active phenolic hydroxyl groups, natural polyphenols are widely used in the food and pharmaceutical industries as potent stabilizers and could be useful for oxidative stability in crosslinked UHMWPE.

Vancomycin-bearing Synthetic Bone Graft Delivers rhBMP-2 and Promotes Healing of Critical Rat Femoral Segmental Defects

Jordan D. Skelly ME, Jeffrey Lange MD, Tera M. Filion PhD, Xinning Li MD, David C. Ayers MD, Jie Song PhD

Bone grafts simultaneously delivering therapeutic proteins and antibiotics may be valuable in orthopaedic trauma care. Previously, we developed a poly(2-hydroxyethyl methacrylate)-nanocrystalline hydroxyapatite (pHEMA-nHA) synthetic bone graft that, when preabsorbed with 400-ng rhBMP-2/7, facilitated the functional repair of critical-size rat femoral defects. Recently, we showed that pHEMA-nHA effectively retains/releases vancomycin and rhBMP-2 in vitro. The success of such a strategy requires that the incorporation of vancomycin does not compromise the structural integrity of the graft nor its ability to promote bone healing.

Fractures in Geriatric Mice Show Decreased Callus Expansion and Bone Volume

Luke A. Lopas MD, Nicole S. Belkin MD, Patricia L. Mutyaba BS, Chancellor F. Gray MD, Kurt D. Hankenson DVM, MS, PhD, Jaimo Ahn MD, PhD

Poor fracture healing in geriatric populations is a significant source of morbidity, mortality, and cost to individuals and society; however, a fundamental biologic understanding of age-dependent healing remains elusive. The development of an aged-based fracture model system would allow for a mechanistic understanding that could guide future biologic treatments.

Do Genetic Susceptibility, Toll-like Receptors, and Pathogen-associated Molecular Patterns Modulate the Effects of Wear?

Edward M. Greenfield PhD

Overwhelming evidence supports the concept that wear particles are the primary initiator of aseptic loosening of orthopaedic implants. It is likely, however, that other factors modulate the biologic response to wear particles. This review focuses on three potential other factors: genetic susceptibility, Toll-like receptors (TLRs), and bacterial pathogen-associated molecular patterns (PAMPs).

A Novel System Improves Preservation of Osteochondral Allografts

James L. Cook DVM, PhD, Aaron M. Stoker PhD, James P. Stannard MD, Keiichi Kuroki DVM, PhD, Cristi R. Cook DVM, MS, Ferris M. Pfeiffer PhD, Chantelle Bozynski DVM, MSc, Clark T. Hung PhD

Osteochondral allografting is an option for successful treatment of large articular cartilage defects. Use of osteochondral allografting is limited by graft availability, often because of loss of chondrocyte viability during storage.

Are Copy Number Variants Associated With Adolescent Idiopathic Scoliosis?

Jillian G. Buchan MS, David M. Alvarado PhD, Gabe Haller PhD, Hyuliya Aferol BS, Nancy H. Miller MD, Matthew B. Dobbs MD, Christina A. Gurnett MD, PhD

Adolescent idiopathic scoliosis (AIS) is a complex genetic disorder that causes spinal deformity in approximately 3% of the population. Candidate gene, linkage, and genome-wide association studies have sought to identify genetic variation that predisposes individuals to AIS, but the genetic basis remains unclear. Copy number variants are associated with several isolated skeletal phenotypes, but their role in AIS, to our knowledge, has not been assessed.

Does Activity Affect Residual Limb Skin Temperatures?

Glenn K. Klute PhD, Elizabeth Huff MS, William R. Ledoux PhD

Many lower limb amputees experience thermal discomfort as a result of wearing a prosthesis. The development of new prosthetic technology to address thermal discomfort requires an understanding of how activity (or inactivity) affects residual limb skin temperatures and how skin temperatures are mapped across the skin-prosthesis interface.

How Has the Introduction of New Bearing Surfaces Altered the Biological Reactions to Byproducts of Wear and Modularity?

Paul H. Wooley PhD

Biological responses to wear debris were largely elucidated in studies focused on conventional ultrahigh-molecular-weight polyethylene (UHMWPE) and some investigations of polymethymethacrylate cement and orthopaedic metals. However, newer bearing couples, in particular metal-on-metal but also ceramic-on-ceramic bearings, may induce different biological reactions.