Clinical Orthopaedics and Related Research ®

A Publication of The Association of Bone and Joint Surgeons ®

Basic Research 169 articles


How Does Bone Strength Compare Across Sex, Site, and Ethnicity?

Stephen H. Schlecht PhD, Erin M. R. Bigelow MS, Karl J. Jepsen PhD

The risk of fragility fractures in the United States is approximately 2.5 times greater among black and white women compared with their male counterparts. On average, men of both ethnicities have wider bones of greater cortical mass compared with the narrower bones of lower cortical mass among women. However, it remains uncertain whether the low cortical area observed in the long bones of women is consistent with their narrower bone diameter or if their cortical area is reduced beyond that which is expected for the sex differences in body size and external bone size.

Biomechanical Outcomes of Bridge-enhanced Anterior Cruciate Ligament Repair Are Influenced by Sex in a Preclinical Model

Ata M. Kiapour PhD, Braden C. Fleming PhD, Martha M. Murray MD

Despite the well-established role of sex on the anterior cruciate ligament (ACL) injury risk, its effects on ACL surgical outcomes remain controversial. This is particularly critical when developing novel surgical techniques to treat the injury because there are limited data existing on how these procedures will respond in each sex. One such approach is bridge-enhanced ACL repair, in which primary suture repair of the ACL is augmented with a bioactive scaffold saturated with autologous blood. It has shown comparable biomechanical outcomes to ACL reconstruction in preclinical models.

Sex Differences in Arm Muscle Fatigability With Cognitive Demand in Older Adults

Hugo M. Pereira MSc, Vincent C. Spears BSc, Bonnie Schlinder-Delap MA, Tejin Yoon PhD, April Harkins PhD, Kristy A. Nielson PhD, Marie Hoeger Bement PhD, Sandra K. Hunter PhD

Muscle fatigability can increase when a stressful, cognitively demanding task is imposed during a low-force fatiguing contraction with the arm muscles, especially in women. Whether this occurs among older adults (> 60 years) is currently unknown.

Platelet-rich Concentrates Differentially Release Growth Factors and Induce Cell Migration In Vitro

Michael O. Schär MD, Jose Diaz-Romero PhD, Sandro Kohl MD, Matthias A. Zumstein MD, Dobrila Nesic PhD

Platelet-rich concentrates are used as a source of growth factors to improve the healing process. The diverse preparation protocols and the gaps in knowledge of their biological properties complicate the interpretation of clinical results.

Women Build Long Bones With Less Cortical Mass Relative to Body Size and Bone Size Compared With Men

Karl J. Jepsen PhD, Erin M. R. Bigelow MS, Stephen H. Schlecht PhD

The twofold greater lifetime risk of fracturing a bone for white women compared with white men and black women has been attributed in part to differences in how the skeletal system accumulates bone mass during growth. On average, women build more slender long bones with less cortical area compared with men. Although slender bones are known to have a naturally lower cortical area compared with wider bones, it remains unclear whether the relatively lower cortical area of women is consistent with their increased slenderness or is reduced beyond that expected for the sex-specific differences in bone size and body size. Whether this sexual dimorphism is consistent with ethnic background and is recapitulated in the widely used mouse model also remains unclear.

Platelet-rich Plasma Modulates the Secretion of Inflammatory/Angiogenic Proteins by Inflamed Tenocytes

Isabel Andia PhD, Eva Rubio-Azpeitia MSc, Nicola Maffulli MD, MS, PhD, FRCS (Orth)

Platelet-rich plasma therapies for tendinopathy appear to provide moderate pain reduction. However, the biological mechanisms behind the observed clinical effects remain poorly characterized.

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.