Clinical Orthopaedics and Related Research ®

A Publication of The Association of Bone and Joint Surgeons ®

Basic Research 173 articles


Physical Stimulation of Chondrogenic Cells In Vitro: A Review

Sibylle Grad PhD, David Eglin PhD, Mauro Alini PhD, Martin J. Stoddart PhD

Mechanical stimuli are of crucial importance for the development and maintenance of articular cartilage. For conditioning of cartilaginous tissues, various bioreactor systems have been developed that have mainly aimed to produce cartilaginous grafts for tissue engineering applications. Emphasis has been on in vitro preconditioning, whereas the same devices could be used to attempt to predict the response of the cells in vivo or as a prescreening method before animal studies. As a result of the complexity of the load and motion patterns within an articulating joint, no bioreactor can completely recreate the in vivo situation.

Bioactive Glass 13-93 as a Subchondral Substrate for Tissue-engineered Osteochondral Constructs: A Pilot Study

Prakash Jayabalan MD, Andrea R. Tan MS, Mohammed N. Rahaman PhD, B. Sonny Bal MD, MBA, Clark T. Hung PhD, James L. Cook DVM, PhD

Replacement of diseased areas of the joint with tissue-engineered osteochondral grafts has shown potential in the treatment of osteoarthritis. Bioactive glasses are candidates for the osseous analog of these grafts.

Androgen Receptor CAG Repeat Size is Associated with Stress Fracture Risk: A Pilot Study

Ran Yanovich MSc, Roni Milgrom MSc, Eitan Friedman MD, PhD, Daniel S. Moran PhD

Stress fractures commonly affect military recruits during basic training. Several lines of evidence suggest genetic factors are involved in stress fracture predisposition. As gender steroid hormone levels and activity have been implicated in affecting bone strength, one of the candidate genes likely to be involved is the androgen receptor gene.

Reduced Wear of Cross-linked UHMWPE Using Magnesia-stabilized Zirconia Femoral Heads in a Hip Simulator

Marcel E. Roy PhD, Leo A. Whiteside MD, Mark E. Magill MD, Brian J. Katerberg BS

To reduce wear, the ideal bearing surface in joint arthroplasty should be smooth and hydrophilic. Ceramics generally offer better wettability than metals and can be polished to a smoother finish. However, clinical studies have found no reduction in liner wear when using yttria-stabilized zirconia (Y-TZP) instead of cobalt chromium alloy (CoCr) femoral heads.

Does Norepinephrine Influence Pain Behavior Mediated by Dorsal Root Ganglia?: A Pilot Study

Katsumasa Tanimoto MD, PhD, Tsuneo Takebayashi MD, PhD, Takeshi Kobayashi MD, PhD, Noritsugu Tohse MD, PhD, Toshihiko Yamashita MD, PhD

Postganglionic neurons in the sympathetic nervous system reportedly are involved in lumbar radicular pain and release norepinephrine (NE), a neurotransmitter. Increased numbers of sympathetic nerve fibers have been found in dorsal root ganglion (DRG) neurons in a root constriction model. Whether this is a reasonable model for pain, however, is unclear

Does Perception of Usefulness of Arthroscopic Simulators Differ with Levels of Experience?

Gabriëlle J. M. Tuijthof PhD, P. Visser MD, Inger N. Sierevelt MSc, C. Niek Dijk MD, PhD, Gino M. M. J. Kerkhoffs MD, PhD

Some commercial simulators are available for training basic arthroscopic skills. However, it is unclear if these simulators allow training for their intended purposes and whether the perception of usefulness relates to level of experience.

Healing of Long-term Frozen Orthotopic Bone Allografts is not Affected by MHC Differences Between Donor and Recipient

Olav Reikerås MD, PhD, Finn P. Reinholt MD, PhD, Severin Zinöcker MSc, Hamid Shegarfi MSc, Bent Rolstad MD, PhD

The use of bone grafting in orthopaedic surgery has increased dramatically in recent years. However, the degree to which immune responses are important for the survival of the allograft is not fully understood. In particular it remains unclear whether differences in the major histocompatibility complex (MHC) influence incorporation of bone allografts and their subsequent biologic performance.

Whole Bone Mechanics and Bone Quality

Jacqueline H. Cole PhD, Marjolein C. H. Meulen PhD

The skeleton plays a critical structural role in bearing functional loads, and failure to do so results in fracture. As we evaluate new therapeutics and consider treatments to prevent skeletal fractures, understanding the basic mechanics underlying whole bone testing and the key principles and characteristics contributing to the structural strength of a bone is critical.

Rationale for and Methods of Superiority, Noninferiority, or Equivalence Designs in Orthopaedic, Controlled Trials

Patrick Vavken MD, MSc, FRSPH

To provide value-based healthcare in orthopaedics, controlled trials are needed to assess the comparative effectiveness of treatments. Typically comparative trials are based on superiority testing using statistical tests that produce a p value. However, as orthopaedic treatments continue to improve, superiority becomes more difficult to show and, perhaps, less important as margins of improvement shrink to clinically irrelevant levels. Alternative methods to compare groups in controlled trials are noninferiority and equivalence. It is important to equip the reader of the orthopaedic literature with the knowledge to understand and critically evaluate the methods and findings of trials attempting to establish superiority, noninferiority, and equivalence.

Coculture of Engineered Cartilage With Primary Chondrocytes Induces Expedited Growth

Andrea R. Tan MS, Elizabeth Y. Dong BS, James P. Andry MD, J. Chloë Bulinski PhD, Gerard A. Ateshian PhD, Clark T. Hung PhD

Soluble factors released from chondrocytes can both enhance and induce chondrocyte-like behavior in cocultured dedifferentiated cells. The ability to similarly prime and modulate biosynthetic activity of differentiated cells encapsulated in a three-dimensional environment is unknown.