Spine and Joint Instability: Orthopedic and Radiologic Approaches

One thing Dr. Donald Resnick taught was to understand the disease rather than the modality. Most musculoskeletal diseases are age-related and there have been varying theories offered to explain this phenomenon. To some degree it is likely a manifestation of ischemia and poor tissue perfusion; to some degree there is likely an accumulation of microdamage sustained from activities of daily living; to some degree this may be related to the size of osseous foramina and sulci with impingement. It is, however, becoming increasing apparent, that many so-called degenerative musculoskeletal disorders are manifestations of clinical or subclinical instability.

Stability is the ability of a musculoskeletal structure or articulation to remain uninjured while it goes through its normal range of motion. Instability is much more than the opposite of this characterization. There is overt instability, which is well known to most clinicians and radiologists. This clinical instability is extremely common in the spine and shoulder and is covered by several excellent articles on those topics in this issue. Instability is also known, though to a somewhat lesser degree, in the elbow and knee, which are also well covered in fine detail in this issue. In addition, there is subclinical instability. It is our feeling that many age-related disorders in the future will be found to be the result of microinstability. Thus, a detailed discussion of spine and joint instability is germane as an aid to understanding the development of these disorders.

We want to personally thank and extend our appreciation to Christine Chung, an outstanding young radiologist and researcher who has put together a phenomenal issue covering the concept of spine and joint instability in a detailed and innovative fashion. We also would like to extend our appreciation to each of the articles' authors. We have been educated by reviewing this work and hope our readership feels the same way.