OSTEOARTHRITIS
The most common type of arthritis
High rate of prevalence in the elderly and leading cause of disability in the
elderly
Joint failure, a disease in which all structures of the joint have undergone
pathologic change often in concert
Hyaline articular cartilage loss (vs RA: involvement of synovium) is the
pathologic sine qua non of the disease (which is present in a focal and
initially non uniform manner)
Non uniform manner initially, it is not always that the lateral and the
medial side are affected together but most often it is the middle side that
is affected.
Accompanied by:
Increasing thickness of the subchondral bony plate
Outgrowth of osteophytes at the joint margin (actually a result of the
attempt of the joint to repair)
Stretching of the articular capsule
Mild synovitis in many affected joints
Weakness of muscles bridging the joint
Figure 1. Thickening of subchondral bony plate
,EPIDEMIOLOGY
Musculoskeletal complaints and disorders are the leading causes of
healthcare visits in clinical practice.
OA occurs in aging population and second to Low Back Pain among
reasons to clinical visits.
Aging higher than 50s
RISK FACTORS
, Systemic Risk Factors: Vulnerability of older joints
Age is the most potent risk factor for OA
o Cartilage thins with age
o Joints protectors fail more often with age
o Muscles that bridge the joint become weaker with age and also
respond less quickly to oncoming impulses
o Sensory nerve input slows with age, retarding the feedback loop of
mechanoreceptors to muscles and tendons related to their tension
and position
o Ligaments stretch with age, making them less able to absorb
impulses
Female
Racial Factor: African-American, Native Americans, non- white
Hispanics
Genetic Susceptibility
Nutritional factors
Intrinsic joint vulnerabilities i.e. previous damage (very common cause of
OA in the young), bridging muscle weakness, increasing bone density,
malalignment of the joint.
Failure to synthesize matrix with loading
Older women are at high risk of OA in all joints
Emerges as women reach their sixth decade
Hormone loss with menopause may contribute to this risk
Risk Factors in the Joint Involvement
Changes in the joint anatomy
Major joint injuries
Tears of ligamentous and fibrocartilaginous structures that protect the
joints such as the;
o Anterior cruciate ligament
o Meniscus in the knee
o Labrum in the hip
Weakness in the quadriceps muscles bridging the knee
Impaired proprioception across the knees
Loading Factors
Obesity
o A well-recognized and potent risk factor for the development of knee
OA and, less so, for hip OA
o Mediated mostly through the increase loading in weight- bearing joints
that occurs in overweight persons
Repeated use of joint and exercise
o Runners, working in machine drills
The most common type of arthritis
High rate of prevalence in the elderly and leading cause of disability in the
elderly
Joint failure, a disease in which all structures of the joint have undergone
pathologic change often in concert
Hyaline articular cartilage loss (vs RA: involvement of synovium) is the
pathologic sine qua non of the disease (which is present in a focal and
initially non uniform manner)
Non uniform manner initially, it is not always that the lateral and the
medial side are affected together but most often it is the middle side that
is affected.
Accompanied by:
Increasing thickness of the subchondral bony plate
Outgrowth of osteophytes at the joint margin (actually a result of the
attempt of the joint to repair)
Stretching of the articular capsule
Mild synovitis in many affected joints
Weakness of muscles bridging the joint
Figure 1. Thickening of subchondral bony plate
,EPIDEMIOLOGY
Musculoskeletal complaints and disorders are the leading causes of
healthcare visits in clinical practice.
OA occurs in aging population and second to Low Back Pain among
reasons to clinical visits.
Aging higher than 50s
RISK FACTORS
, Systemic Risk Factors: Vulnerability of older joints
Age is the most potent risk factor for OA
o Cartilage thins with age
o Joints protectors fail more often with age
o Muscles that bridge the joint become weaker with age and also
respond less quickly to oncoming impulses
o Sensory nerve input slows with age, retarding the feedback loop of
mechanoreceptors to muscles and tendons related to their tension
and position
o Ligaments stretch with age, making them less able to absorb
impulses
Female
Racial Factor: African-American, Native Americans, non- white
Hispanics
Genetic Susceptibility
Nutritional factors
Intrinsic joint vulnerabilities i.e. previous damage (very common cause of
OA in the young), bridging muscle weakness, increasing bone density,
malalignment of the joint.
Failure to synthesize matrix with loading
Older women are at high risk of OA in all joints
Emerges as women reach their sixth decade
Hormone loss with menopause may contribute to this risk
Risk Factors in the Joint Involvement
Changes in the joint anatomy
Major joint injuries
Tears of ligamentous and fibrocartilaginous structures that protect the
joints such as the;
o Anterior cruciate ligament
o Meniscus in the knee
o Labrum in the hip
Weakness in the quadriceps muscles bridging the knee
Impaired proprioception across the knees
Loading Factors
Obesity
o A well-recognized and potent risk factor for the development of knee
OA and, less so, for hip OA
o Mediated mostly through the increase loading in weight- bearing joints
that occurs in overweight persons
Repeated use of joint and exercise
o Runners, working in machine drills
