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In Depth Tutorials and Information
CHAPTER
38
Osteoarthritis and Other Joint
Involvement
Bansari Gujar and Marc Hochberg
University of Maryland School of Medicine, Baltimore, MD, USA
INTRODUCTION
ligaments and tendons. It is also extremely critical in the
formation of blood vessels and sclerae and thus defects
in the structure of type I collagen can lead to the wide-
spread manifestations of OI.
Musculoskeletal manifestations of OI have been stud-
ied by several authors; however, only few have opined
on the relationship between OI and OA. We will review
the association between OI and OA and other forms of
arthritis in this chapter; fractures, muscle and tendon
involvement and spinal involvement are reviewed else-
where in the topic (Chapter 36 and Chapters 42-49)
The American College of Rheumatology (ACR)
defined osteoarthritis (OA) as “…a heterogeneous group
of conditions that lead to joint symptoms and signs
which are associated with defective integrity of articular
cartilage, in addition to related changes in the underly-
ing bone and at the joint margins.”
1
This definition, pub-
lished over 25 years ago, represents a chondrocentric
view of osteoarthritis centered on the primacy of changes
in the articular cartilage. Since then, the concept of osteo-
arthritis as a disease of the total joint has evolved. Indeed,
in 2011, the Osteoarthritis Research Society International
(OARSI) Disease State Working Group published a con-
sensus definition of osteoarthritis that identified OA as
“…a progressive disease representing the failed repair
of joint damage that, in the preponderance of cases, has
been triggered by abnormal intra-articular stress.”
2
All
of the tissues of the joint are involved, including not only
the articular cartilage but also the subchondral bone, liga-
ments, periarticular structures and menisci, when pres-
ent. The result of the OA process is cartilage degradation
and bone remodeling; these features are associated with
the development of symptoms of pain, stiffness and func-
tional disability. In this revised concept of OA, the struc-
tural changes represent the disease while the symptoms
of aching, discomfort, pain and stiffness represent the ill-
ness for which patients seek medical care.
Osteogenesis imperfecta (OI) is an inherited disorder
of connective tissue with varying presentations. OI is
most commonly caused by mutations in genes encod-
ing the alpha-1 and alpha-2 chains of type I collagen.
3
Type I collagen is the major protein of human extracel-
lular matrix and is critical in the formation of bones, skin,
OSTEOARTHRITIS
Osteoarthritis is a heterogeneous and multifacto-
rial disease characterized by cartilage degradation and
remodeling of the subchondral bone. The role of bone
in OA has been investigated for 40 years since the ini-
tial work of Foss and Byers that showed a direct rela-
tionship between bone mass, measured at the second
metacarpal, and hip OA as compared with hip fracture.
4
The results of subsequent cross-sectional and longitudi-
nal clinical and population-based epidemiologic studies
that largely confirmed an association between increased
bone mass and OA were reviewed by Hochberg and
Meyer in 2005.
5
The mechanisms underlying the rela-
tionship between bone mass and OA have been attrib-
uted to several factors including (1) shared heritability
and genetic factors; (2) alterations in the rate of bone
turnover, especially in subchondral bone; and (3) struc-
tural alterations in the subchondral bone leading to
alterations in biomechanical forces applied to articular
cartilage.
