Osteoarthritis

See Also

Epidemiology

Most common form of Arthritis
Associated functional Impairment increases with age
Prevalence directly increases with age
1. Age over 40 years: 70% of U.S. population
2. Age over 65 years: 80% of U.S. population
3. See Rheumatologic Conditions in the Elderly

Pathophysiology

Primary lesion resides in the articular cartilage
1. Abnormal cartilage repair and remodeling
2. Chondrocytes produce proteolytic enzymes
3. Proteolytic enzymes destroy cartilage
End result
1. Asymmetric joint cartilage loss
2. Subchondral sclerosis (bone density increased)
3. Subchondral cysts
4. Marginal osteophytes

Risk Factors

Age over 50 years old
Female gender
Obesity
Prior joint injury
Job duties with frequent squatting or bending
Osteoarthritis Family History
Repetitive-impact sports (e.g. soccer, football)

Etiologies

Primary
1. Weight bearing joints
  1. Hands
  2. Hips, Knees, and feet
2. Stressors
  1. Obesity (single most important factor)
  2. Overuse injuries
Secondary
1. Acute or Chronic Trauma
2. History of knee meniscectomy
3. Congenital abnormalities
4. Rheumatic Conditions
  1. Gouty Arthritis
  2. Rheumatoid Arthritis
  3. Calcium pyrophosphate deposition disease (CPPD)
5. Endocrine Conditions
  1. Diabetes Mellitus
  2. Acromegaly

Symptoms

Pain worse later in the day, and better with rest
1. Pain on motion that worsens with increasing joint usage (gelling)
2. If morning stiffness is present, is of short duration (<30 minutes)
  1. Contrast with Rheumatoid Arthritis which has morning stiffness >30 minutes
Slowly progressive deformity and variably painful
1. Initial high-use Joint Pain relieved with rest
2. Next, pain is constant on affected joint usage
3. Eventually pain occurs at rest and at night
No systemic manifestations
1. No Fatigue
2. No generalized weakness
Associated Muscle spasm, contractures and atrophy
Symptoms uncommon before age 40 years old
Asymmetric involvement

Signs

Joint Exam
1. Joint Effusion
2. Atrophy
3. Joint instability
4. Joint tenderness
5. Crepitation
6. Limited range of motion
Joints spared (Contrast with Rheumatoid Arthritis)
1. Wrist spared
2. Metacarpal-phalangeal joints spared (except thumb)
3. Elbow spared
4. Ankle spared (variable involvement)
Joints commonly involved
1. See Shoulder Osteoarthritis
2. See Acromioclavicular Osteoarthritis
3. See Knee Osteoarthritis
4. See Hip Osteoarthritis
5. See Foot Osteoarthritis
6. See Hand Osteoarthritis
  1. Distal interphalangeal joints (Heberden's Nodes)
  2. Proximal interphalangeal joints (Bouchard's Nodes)
  3. First carpometacarpal joint (thumb)
7. Cervical and Lumbar Spine
  1. Mechanisms
    1. Apophyseal joint Arthritis and Osteophytes
    2. Disc degeneration
  2. Secondary affects
    1. Local Muscle spasm
    2. Nerve root impingement with radiculopathy
    3. Cervical stenosis
    4. Lumbar Stenosis (Pseudoclaudication)

Labs
General (if indicated)

Routine labs are not indicated in typical Osteoarthritis
1. Obtain for unclear diagnosis
2. Abnormal results suggest alternative diagnosis
Erythrocyte Sedimentation Rate normal
C-Reactive Protein normal
Rheumatoid Factor negative
Uric Acid normal

Labs
Synovial Fluid (if indicated)

Synovial Fluid appearance
1. Clear fluid
2. High viscosity and good mucin
Synovial Fluid Crystals
1. Basic Calcium Phosphate (BCP) Crystals
2. Apatite crystals
Synovial Fluid White Blood Cell Count
1. Non-Inflammatory fluid: 200 - 2000 WBC/mm3
2. WBC Count usually <500 cells (mostly mononuclear)

Differential Diagnosis
General

Bursitis or Tendonitis
Mechanical intra-articular disorder
Rheumatoid Arthritis
Psoriatic Arthritis
Gouty Arthritis
Pseudogout
Lyme Disease
Hemochromatosis
Hyperparathyroidism
Acromegaly
Wilson Disease
Musculoskeletal Autoimmune Conditions (e.g. Systemic Lupus Erythematosus, Ankylosing Spondylitis)

Differential Diagnosis
By Region

Imaging

Imaging is not required for Osteoarthritis diagnosis in patients with typical presentations
1. XRay, MRI Imaging often does not correlate with Osteoarthritis severity and patient function
  1. Kim (2015) BMJ 351:h5983 +PMID:26631296 [PubMed]
Imaging indicated for pre-operative evaluation or if other diagnosis considered
1. Joint Trauma
2. Joint Pain at night
3. Progressive Joint Pain
4. Family History of other arthritic conditions
5. Age under 18 years
Findings
1. See Osteoarthritis XRay
2. See Foot XRay in Osteoarthritis
3. See Hand XRay in Osteoarthritis
4. See Hip XRay in Osteoarthritis
5. See Knee XRay in Osteoarthritis
6. See Spine XRay in Osteoarthritis

Management
Non-Pharmacologic Treatment

See Knee Osteoarthritis for Muscle Strengthening
Reduce Obesity
1. Weight loss of 5% from baseline or 6 kg (13 pounds) decreases pain and Disability
Physical Therapy
Physiotherapy (Heat, Cold, Contrast Baths or Ultrasound)
1. TENS not found to be effective
Consider comorbidity
1. See Depression in the Elderly
Exercise Program (do not exacerbate symptoms)
1. Stretching
2. Mild aerobic, active, Isometric Exercise (eliptical trainer, Bicycle)
3. Swimming
  1. Highly effective Exercise for strength, flexibility and aerobic fitness
4. Tai chi
  1. Song (2003) J Rheumatol 30:2039-44 [PubMed]
Joint protection
Work and home modified in severe disease
1. Limit weight bearing on affected joints
2. Walk Aids (Canes and Walkers)
Surgery
1. Hip replacement or knee replacement in refractory cases

Management
Pharmacologic Management

Acetaminophen (Tylenol) 1 gram orally twice daily (limit to 2-3 grams daily)
1. Less effective than NSAIDs, but safer
NSAIDs
1. Cautious use in age over 65 years, prior GI Bleed, Aspirin, Plavix, Warfarin or Corticosteroid
  1. Consider with Proton Pump Inhibitor if 1-2 GI risks
  2. Avoid NSAIDs completely if 3 or more GI risks
2. Avoid Feldene - higher risk of GI toxicity
3. Naproxen may have less Cardiovascular Risks
4. Observe for CNS effects (esp. Indomethacin)
5. Consider topical Diclofenac (see below)
6. Switch classes when one NSAID is not effective
  1. Diclofenac (Voltaren) 50 mg two to three times daily
  2. Naproxen Sodium (Naprosyn) 500 mg orally twice daily
  3. Ibuprofen (Advil) 600 mg three times daily
  4. Meloxicam (Mobic) 15 mg daily
  5. Nabumetone (Relafen) 500 mg twice daily
  6. Sulindac (Clinoril) 200 mg twice daily
COX2 Inhibitors
1. Celecoxib (Celebrex) 200 mg daily
2. No advantages to standard NSAIDs and still very expensive
Topical agents
1. Topical Diclofenac
  1. May be as effective as oral NSAIDs if only a few joints involved
  2. Expensive and risk of skin reaction
2. Topical Capsaicin cream
  1. Effective for refractory Joint Pain
  2. Poorly tolerated
3. Avoid topical Salicylates such as Bengay (ineffective for Osteoarthritis)
Intraarticular agents
1. Intra-articular Corticosteroid injection
  1. Avoid more than 3-4 times per year
2. Sodium hyaluronate (Synvisc) in Knee Osteoarthritis
Other systemic Analgesics
1. Tramadol (Ultram)
  1. Effective, but with risks (NNT 6, NNH 8)
  2. Cepeda (2007) J Rheumatol 34(3): 543-55 [PubMed]
2. Duloxetine (Cymbalta)
  1. Effective, but with moderate Nausea risk (NNT 7, NNH 6)
    1. Also causes Constipation, Xerostomia, Dizziness and Fatigue
    2. Citrome (2012) Postgrad Med 124(1): 83-93 [PubMed]
  2. Duloxetine, Milnacipran, SSRIs and Tricyclic Antidepressants offer a small pain and function benefit (hip, knee OA)
    1. However, adverse effects (see above) limit their use
    2. Consider in Comorbid Mood Disorder (Major Depression, Anxiety Disorder)
    3. Leaney (2022) Cochrane Database Syst Rev (10): CD012157 [PubMed]
3. Opioids
  1. Generally not recommended due to significant risks

Management
Alternative Medications

Possibly effective agents (insufficient evidence to recommend)
1. Dimethyl Sulfoxide (DMSO) 25% applied topically
  1. Small, 3 week studies showed reduced pain
2. Devil's Claw 2.4 grams daily
3. Ginger Extract 510 mg daily
4. Methlsulfonylmethane (MSM) 500 mg three times daily
5. S-Adenosylmethionine (SAMe) 200 mg three times daily
  1. Methyl donor in proteoglycan synthesis
  2. More effective than Placebo for pain, stiffness
  3. Very expensive and unstable shelf life (Butanedisulfonate salt is most stable)
6. Glucosamine Sulfate
  1. Dosing 1500 mg once daily or 500 mg orally three times daily
  2. Effect may be delayed for 2 months
  3. Initial studies demonstrated benefit
    1. Towheed (2005) Cochrane Database Syst Rev (2):CD002946 [PubMed]
    2. Richy (2003) Arch Intern Med 163(13):1514-22 [PubMed]
  4. Later studies show no significant benefit
    1. Roman-blas (2017) Arthritis Rheumatol 69(1): 77-85 [PubMed]
    2. Wilkins (2010) JAMA 304(1):45-52 [PubMed]
Unknown benefit (anecdotal, inconclusive data or only small studies support)
1. Avocado-soybean unsaponifiables 300 mg daily
2. Boron supplementation
  1. Effects Calcium Metabolism in bones, joints
  2. Higher Arthritis rates with low boron intake
3. Cetyl Myristoleate (anti-inflammatory effects)
4. Acupuncture
5. FLUIDjoint
  1. Concentrated milk Proteins from New Zealand
  2. Promoted as containing antibodies for Immunity
  3. Not recommended due to $50/month and unproven
Agents to avoid
1. Agents that are ineffective for Osteoarthritis (but may have other indications)
  1. Vitamin D Supplementation
  2. Antioxidant supplements
2. Ineffective agents (avoid these based on high quality studies)
  1. Chondroitin sulfate 400 mg orally three times daily
  2. Tipi
  3. Reumalex
  4. Ionized wrist bracelets
  5. Osteoarthritis Shoes
3. Preparations with serious adverse effects and either ineffective or unproven efficacy
  1. Limbrel (Flavocoxid)
    1. Risk of Acute Hepatitis and Hypersensitivity pneumonitis
References
1. Morelli (2003) Am Fam Physician 67(2):339-44 [PubMed]
2. Gregory (2008) Am Fam Physician 77(2): 177-84 [PubMed]

Prevention

Maintain appropriate body weight
Continued moderate joint activity is critical
1. Normal joint use directs cartilage remodeling
2. Decreased joint use risks abnormal cartilage repair

Resources
Patient Education

Information from your Family Doctor: Staying Active
1. http://www.familydoctor.org/healthfacts/115/

References