Related Experiment Video
Updated: Jul 18, 2026
Standardized Histomorphometric Evaluation of Osteoarthritis in a Surgical Mouse Model
Published on: May 6, 2020
Histologic classification of loose bodies in osteoarthrosis
Koichi Saotome1, Kazuya Tamai, Denju Osada
1Department of Orthopaedics, Dokkyo Medical University, Mibu-machi, Shimotsuga-gun, Tochigi, 321-0293, Japan.
Background:
Histologically based analyses of the nature and origin of loose bodies occurring in osteoarthrosis have been few, and further study is warranted.
Methods:
We histologically examined 84 loose bodies and 9 related lesions (synovial membrane nodules) surgically removed from 24 joints of 24 patients with osteoarthrosis.
Results:
The 84 loose bodies included 48 chondral loose bodies (type I), 26 osteochondral loose bodies (type II), and 10 osseous loose bodies (type III). The 26 osteochondral loose bodies (type II) could be subdivided into 8 composed of cartilage with enchondral ossification (type IIa), 11 consisting of mature bone covered by cartilage without enchondral ossification (type IIb), and 7 made up of mature bone and partially articular cartilage or hyaline cartilage (type IIc). Synovial membrane nodules could be also divided into three types in the same manner as loose bodies. Many type IIa, type IIc and type III loose bodies and all synovial membrane nodules showed blood vessels containing red blood cells, as well as osteoclasts. The type I and type IIb loose bodies, however, did not show them.
Conclusions:
It is well known that loose bodies grow from proliferation of cartilage without blood supply in the joint cavity, and that enchondral ossification is able to develop only under the condition of having a blood supply. As synovial membrane nodules were also classified to the same types as loose bodies and more than half of osteochondral and osseous loose bodies contained blood vessels with red blood cells, the loose bodies were thought to be caught in the synovial membrane and to be modified as the result of a blood supply. Considering the results of this study, the various histologic characteristics of loose bodies in osteoarthrosis resulted from modifications including cartilage proliferation in the joint cavity and enchondral ossification in the synovial membrane.
Related Concept Videos
01:20Structural Classification of Joints
A fibrous joint is where the adjacent bones are united by fibrous connective...
01:30Classification of Connective Tissues
Connective Tissue Proper
Connective tissue proper is the most abundant class of connective tissues. As its name implies, it predominantly connects different tissues in the body. Depending on the cell types, ground substance, viscosity, and fiber types in the ECM, connective tissue proper is further categorized into loose and dense.
01:09Functional Classification of Joints
The functional classification of joints is determined by the amount of mobility between the adjacent bones. Joints are functionally classified as a synarthrosis or immobile joint, an amphiarthrosis or slightly moveable joint, or as a diarthrosis, a freely moveable joint. Fibrous and cartilaginous joints can be functionally classified as either synarthroses or amphiarthroses, whereas all synovial joints are classified as diarthroses.
Synarthrosis
An immobile...
01:18Classification of Bones
Long and Short Bones
The appendicular skeleton, particularly the upper and lower limbs, is primarily made of long and short bones. The long...
01:25Overview of Connective Tissues Proper
The loose connective tissues have a meshwork of thin collagen and elastin fibers, which provide tensile strength for support and enough elasticity to move cells. They have...
01:26Joints
Structural joint classifications are based on the material that makes up the joint as well as whether or not the joint contains a space between the bones. Joints are structurally classified as fibrous, cartilaginous, or synovial.
Fibrous Joints Are Immovable
The bones of a...