Osteoarthritis

'I have fallen, and I can't get up"

Osteoarthritis

Degenerative joint disease, chronic, affects more than 20 million Americans

Articular (hyaline) cartilage in the synovial joints breaks down and causes pain, swelling, and restricts movement of joints

Osteoarthritis predominantly involves the weight-bearing joints, including the knees, hips, cervical and lumbosacral spine, and feet

Other commonly affected joints include the distal interphalangeal (DIP), proximal interphalangeal (PIP), and carpometacarpal (CMC) joints

Primary

Related to the aging process and typically occurs in older individuals, it is an idiopathic phenomenon, occurring in previously intact joints and having no apparent initiating factor

NOTE: the term primary, or idiopathic, osteoarthritis may become obsolete…many investigators believe that most cases of primary osteoarthritis of the hip may, in fact, be due to subtle or even unrecognizable congenital or developmental defects.

Secondary

Disease of the synovial joints that results from some predisposing condition that has adversely altered the joint tissues (eg, trauma to articular cartilage or subchondral bone). Secondary osteoarthritis can occur in relatively young individuals

In early osteoarthritis

Swelling of the cartilage usually occurs, because of the increased synthesis of proteoglycans; this reflects an effort by the chondrocytes to repair cartilage damage.

This stage may last for years or decades and is characterized by hypertrophic repair of the articular cartilage

As osteoarthritis progresses

The level of proteoglycans eventually drops very low, causing the cartilage to soften and lose elasticity and thereby further compromising joint surface integrity.

Microscopically, flaking and fibrillations (vertical clefts) develop along the normally smooth articular cartilage on the surface of an osteoarthritic joint.

Over time, the loss of cartilage results in loss of joint space

Erosion of the damaged cartilage in an osteoarthritic joint

progresses until the underlying bone is exposed. Bone denuded of its protective cartilage continues to articulate with the opposing surface.

Eventually, the increasing stresses exceed the biomechanical yield strength of the bone. The subchondral bone responds with vascular invasion and increased cellularity, becoming thickened and dense

Mechanisms that occur within this disease

  • Osteophytic periosteal elevation
  • Vascular congestion of subchondral bone, leading to increased intraosseous pressure
  • Synovitis with activation of synovial membrane nociceptors
  • Fatigue in muscles that cross the joint
  • Overall joint contracture
  • Joint effusion and stretching of the joint capsule
  • Torn menisci
  • Inflammation of periarticular bursae
  • Periarticular muscle spasm
  • Psychological factors
  • Crepitus (a rough or crunchy sensation)
  • Central pain sensitization
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Interleukin-1 causes chondrocytes and synovial cells and synthesis of matrix metalloproteinases, which are responsible for the degradation of cartilage


  • Abnormal integrin expression alters cell/ECM signaling and modifies chondrocyte synthesis, with the following imbalance of destructive cytokines over regulatory factors.
  • IL-1, TNF-alpha and other pro-catabolic cytokines activate the enzymatic degradation of cartilage matrix and are not counterbalanced by adequate synthesis of inhibitors
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Age

  • Reduction in cartilage volume, proteoglycan content, cartilage vascularization and cartilage perfusion
  • Narrowed joint space
  • Not enough on its own to cause OA
  • > 65 y/o

Obesity


  • Increase in mechanical stress in weight-bearing joints
  • Inflammatory risk (adipokines - cytokines derived from adipose tissue)
  • Trauma
  • Abnormal biomechanics
  • Muscle dysfunction compromises neuromuscular protective mechanisms leading to increased joint motion and OA
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Jamie Oliver - TED Talk on Obesity and Food

Genetics

  • Genes: ADAM12, CLIP, IL10, and MMP3 lead to differential methylation leading to collagen degradation
  • COL1A2 mutations lead to early onset OA
  • MCF2L is key in neutrophin-mediated regulation of peripheral nervous system cell motility
  • Heritability
  • Reduced levels of sex hormones
  • Muscle weakness
  • Repetitive use
  • Infection
  • Crystal deposition
  • Acromegaly
  • Previous inflammatory arthritis
  • Heritable metabolic causes (Wilson Disease, hemochromatosis)
  • Hemoglobinopathies (Sickle Cell Disease, thalassemia)
  • Neuropathic disorders leading to a Charcot joint
  • Underlying morphologic risk factors (congenital hip dislocation)
  • Disorders of bone (Paget Disease)
  • Previous surgical procedures
  • > 55 y/o, women are at a higher risk than men
  • Native Americans are at higher risk than another other population
  • Whites more common than blacks
Osteoarthritis gene therapy being developed at UF could help both people, animals

Diagnostics (labs, testing, screening)

· Differentiate osteoarthritis from others, such as rheumatoid arthritis

· History and physical exam is sufficient to diagnose osteoarthritis

· Radiographs confirm the initial impression and laboratory values

· No specific laboratory abnormalities are associated with OA

· No single biomarker has proved reliable for diagnosis and monitoring, but

combinations of cartilage-derived and bone-derived biomarkers have been used to

identify OA subtypes

GOAL: Alleviation of pain and improvement of functional status

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Nonpharmacologic interventions

Patient education
Heat and cold
Weight loss

Exercise

  • Cardiovascular or resistance land-based exercise
  • Aquatic exercise
  • Tai chi

Physical therapy

Occupational therapy

Unloading in certain joints

Assistive devices

Acupuncture

Surgery

  • Athroscopy, osteotomy, and arthroplasty

Fusion and Joint Lavage

Pharmacologic interventions


  • Topical capsaicin
  • Topical / Oral NSAIDs
  • Tramadol
  • Acetaminophen
  • Intra-articular corticosteroid injections
  • Opioids
  • Pain patches
  • Growth factor injections
  • Duloxetine (selective serotonin-norepinephrine reuptake inhibitor)
  • Skeletal muscle relaxants
euflexxa knee injection animation

*Vary depending on the joint(s) effected*

Pain

Worse after activity or toward end of day

Tenderness
Stiffness

First thing in the morning or after rest

Loss of flexibility
Grating sensation (crepitus)
Bone spurs
Effected joints get swollen, especially after extended activity

Areas

Hips

Pain is felt in groin area or buttocks and sometimes inside knee or thigh

Knees

A “grating/scraping” sensation occurs when moving knees

Fingers

Bony growth (spurs) at edge of joints. Causes swelling, tenderness, and redness. Pain at the base of thumb.

Feet

Pain and tenderness felt in large joint at base of big toe. Swelling in ankles or toes.

Upper extremities

Pain, swelling, stiffness may make ordinary tasks very difficult (ex. Making bed, opening box of food, using computer mouse, driving car, writing, holding/grasping items).

Lower extremities

Pain, swelling, stiffness may make ordinary tasks very difficult (ex. Walking, climbing stairs, lifting objects)

NOTE

Knee/hip pain may lead to sedentary lifestyle that promotes weight gain and obesity. Can then lead to development of diabetes, heart disease, and hypertension.

References

Arthritis Foundation. (2015). Osteoarthritis. Retrieved from http://www.arthritis.org/about-arthritis/types/osteoarthritis/what-is-osteoarthritis.php


Expanscience Laboratories. (2015). Osteoarthritis. Retrieved from http://www.arthrolink.com/en/disease/understanding/mechanisms-osteoarthritis


Lozada. C. (2015, March 27). Osteoarthritis. Retrieved from http://emedicine.medscape.com/article/330487-overview


The Mayo Clinic Staff. (2014, Oct 9). Disease and Conditions: Osteoarthritis. Retrieved from http://www.mayoclinic.org/diseases-conditions/osteoarthritis/basics/definition/con-20014749


Osteoarthritis. (n.d.). Retrieved December 1, 2015, from https://youtu.be/41IMR_Dp5bs


Osteoarthritis gene therapy being developed at UF could help both people, animals. (n.d.). Retrieved December 1, 2015, from https://youtu.be/WCfck1H_b_U


Euflexxa knee injection animation. (n.d.). Retrieved December 1, 2015, from https://youtu.be/Sa_-NSByo-0


Jamie Oliver - TED Talk on Obesity and Food. (n.d.). Retrieved December 1, 2015, from https://youtu.be/wOPl8P2S-Lw

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