Osteolysis is an active
resorption
Resorption is the absorption of cells or tissue into the circulatory system, usually by osteoclasts.
Types of resorption include:
* Bone resorption
Bone resorption is resorption of bone tissue, that is, the process by which osteoclasts break ...
of
bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...
matrix by
osteoclast
An osteoclast () is a type of bone cell that breaks down bone tissue. This function is critical in the maintenance, repair, and bone remodeling, remodeling of bones of the vertebrate, vertebral skeleton. The osteoclast disassembles and digests th ...
s and can be interpreted as the reverse of
ossification
Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...
. Although osteoclasts are active during the natural formation of healthy bone the term "osteolysis" specifically refers to a pathological process. Osteolysis often occurs in the proximity of a
prosthesis
In medicine, a prosthesis (: prostheses; from ), or a prosthetic implant, is an artificial device that replaces a missing body part, which may be lost through physical trauma, disease, or a condition present at birth (Congenital, congenital disord ...
that causes either an immunological response or changes in the bone's
structural load
A structural load or structural action is a mechanical load (more generally a force) applied to Structural engineering#Structural elements, structural elements. A load causes stress (physics), stress, deformation (engineering), deformation, displa ...
. Osteolysis may also be caused by pathologies like
bone tumor
A bone tumor is an abnormal growth of tissue in bone, traditionally classified as noncancerous (benign) or cancerous (malignant). Cancerous bone tumors usually originate from a cancer in another part of the body such as from lung, breast, th ...
s, cysts, or chronic inflammation.
Joint replacement
While
bone resorption
Bone resorption is resorption of bone tissue, that is, the process by which osteoclasts break down the tissue in bones and release the minerals, resulting in a transfer of calcium from bone tissue to the blood.
The osteoclasts are multi-nuclea ...
is commonly associated with many diseases or joint problems, the term ''osteolysis'' generally refers to a problem common to artificial joint replacements such as
total hip replacement
Hip replacement is a surgical procedure in which the hip joint is replaced by a prosthetic implant, that is, a hip prosthesis. Hip replacement surgery can be performed as a total replacement or a hemi/semi(half) replacement. Such joint replacem ...
s, total knee replacements and total shoulder replacements. Osteolysis can also be associated with the radiographic changes seen in those with bisphosphonate-related
osteonecrosis
Avascular necrosis (AVN), also called osteonecrosis or bone infarction, is death of bone tissue due to interruption of the blood supply. Early on, there may be no symptoms. Gradually joint pain may develop, which may limit the person's abili ...
of the jaw.
There are several biological mechanisms which may lead to osteolysis. In total hip replacement, the generally accepted explanation for osteolysis involves wear particles (worn off the contact surface of the artificial
ball and socket joint
The ball-and-socket joint (or spheroid joint) is a type of synovial joint in which the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone. The distal bone is capable of motion around an indefinite number of ...
). As the body attempts to clean up these wear particles (typically consisting of plastic or metal), it triggers an
autoimmune
In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an " autoimmune disease" ...
reaction which causes resorption of living bone tissue. Osteolysis has been reported to occur as early as 12 months after implantation and is usually progressive. This may require a revision
surgery
Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...
(replacement of the prosthesis).
Although osteolysis itself is clinically
asymptomatic
Asymptomatic (or clinically silent) is an adjective categorising the medical conditions (i.e., injuries or diseases) that patients carry but without experiencing their symptoms, despite an explicit diagnosis (e.g., a positive medical test).
P ...
, it can lead to implant loosening or bone breakage, which in turn causes serious medical problems.
Distal clavicular osteolysis
Distal clavicular osteolysis (DCO) is often associated with problems weightlifters have with their
acromioclavicular joint
The acromioclavicular joint, or AC joint, is a joint at the top of the shoulder. It is the junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle. It is a Plane joint, plane synovial joint ...
s due to high mechanical stresses put on the
clavicle
The clavicle, collarbone, or keybone is a slender, S-shaped long bone approximately long that serves as a strut between the scapula, shoulder blade and the sternum (breastbone). There are two clavicles, one on each side of the body. The clavic ...
as it meets with the
acromion
In human anatomy, the acromion (from Greek: ''akros'', "highest", ''ōmos'', "shoulder", : acromia) or summit of the shoulder is a bony process on the scapula (shoulder blade). Together with the coracoid process, it extends laterally over the sh ...
. This condition is often referred to as "weight lifter's shoulder".
[ ]Medical ultrasonography
Medical ultrasound includes Medical diagnosis, diagnostic techniques (mainly medical imaging, imaging) using ultrasound, as well as therapeutic ultrasound, therapeutic applications of ultrasound. In diagnosis, it is used to create an image of ...
readily depicts resorption of the distal clavicle as irregular cortical erosions, whereas the acromion remains intact.[Arend CF. Ultrasound of the Shoulder. Master Medical Books, 2013. Sample chapter available a]
ShoulderUS.com
/ref> Associated findings may include distended joint capsule, soft tissue
Soft tissue connective tissue, connects and surrounds or supports internal organs and bones, and includes muscle, tendons, ligaments, Adipose tissue, fat, fibrous tissue, Lymphatic vessel, lymph and blood vessels, fasciae, and synovial membranes. ...
swelling, and joint instability
Joint stability refers to the resistance offered by various Musculoskeletal system, musculoskeletal tissues that surround a skeletal joint. Several subsystems ensure the stability of a joint. These are the passive, active and neural subsystems. It ...
.
A common surgery to treat recalcitrant DCO is resection of distal clavicle by removing a few millimetres of bone from the very end of the bone.
See also
* Osteolytic lesion
* Biomineralization
Biomineralization, also written biomineralisation, is the process by which living organisms produce minerals, often resulting in hardened or stiffened '' mineralized tissues''. It is an extremely widespread phenomenon: all six taxonomic kingd ...
References
External links
{{Musculoskeletal physiology
Geriatrics
Orthopedic surgical procedures
Musculoskeletal disorders
Arthritis