Osteoarthritis

Definition Also known as degenerative joint disease or “wear and tear arthritis”. Also known as degenerative joint disease or “wear and tear arthritis”. Progressive loss of cartilage with remodeling of subchondral bone and progressive deformity of the joint (s). Progressive loss of cartilage with remodeling of subchondral bone and progressive deformity of the joint (s). Cartilage destruction may be a result of a variety of etiologies Cartilage destruction may be a result of a variety of etiologies

Prevalence and epidemiology It’s the commonest form of arthritis It’s the commonest form of arthritis About 60-90% of people over age 65 About 60-90% of people over age 65 Under 45 yrs it is equally common in men and women Under 45 yrs it is equally common in men and women Over 55 yrs its more common in women Over 55 yrs its more common in women Nodal OA involving DIP and PIP joints is more common in women and their first degree female relatives Nodal OA involving DIP and PIP joints is more common in women and their first degree female relatives

Premature OA associated with gene mutations that encode collagen types 2, 9, 10 Premature OA associated with gene mutations that encode collagen types 2, 9, 10 OA of knee is more common in women OA of knee is more common in women Commonest cause of long-term disability Commonest cause of long-term disability Large economic impact as a result of medical costs Large economic impact as a result of medical costs

It is not an inevitable part of aging, some people are more susceptible than others It is not an inevitable part of aging, some people are more susceptible than others A combination of different factors are involved. A combination of different factors are involved. Both mechanical and biologic destructive processes play a role in OA. Both mechanical and biologic destructive processes play a role in OA.

Risk factors Metabolic (hemachromatosis) Metabolic (hemachromatosis) Inflammatory (RA, infection) Inflammatory (RA, infection) age age gender gender genetic factors genetic factors trauma trauma weight weight

Classification Primary Primary Idopathic Idopathic Localized or generalized Localized or generalized  Local: knee, hip, spine, hands  Generalized: large joints and spine  Small peripheral joints and spine  Mixed and spine Secondary Secondary Post-traumataic Post-traumataic Congenital or developmental Congenital or developmental Localized or generalized Localized or generalized Calcium deposition disease Calcium deposition disease

Inflammatory OA OA is generally a non-inflammtory arthritis. OA is generally a non-inflammtory arthritis. Increasing evidence for inflammatory type: caused by cytokines, metalloproteinase release. Increasing evidence for inflammatory type: caused by cytokines, metalloproteinase release. This erosive inflammatory type may have flares but later acts like typical OA. This erosive inflammatory type may have flares but later acts like typical OA. Primarily in women Primarily in women May be suspected from evidence of active synovitis, chondrocalcinosis on x-rays, morning stiffness greater than 30 mins, history of swelling and night pain. May be suspected from evidence of active synovitis, chondrocalcinosis on x-rays, morning stiffness greater than 30 mins, history of swelling and night pain.

Overview of the process Articular cartilage gets disrupted Articular cartilage gets disrupted Damage progresses deeper to subchondral bone Damage progresses deeper to subchondral bone

Fragments of cartilage released into joint Fragments of cartilage released into joint Matrix degenerates Matrix degenerates Eventually there is complete loss of cartilage Eventually there is complete loss of cartilage Bone is exposed Bone is exposed

Normal knee anatomy

left: Normal x-ray left: Normal x-ray Right: worn away cartilage reflected by decreased joint space Right: worn away cartilage reflected by decreased joint space

The process – at a cellular level Cartilage matrix has increased water content and decreased proteoglycan Cartilage matrix has increased water content and decreased proteoglycan With aging  cartilage dries up. With aging  cartilage dries up. Increased activity of proteinases compared to inhibitors of proteinases. Increased activity of proteinases compared to inhibitors of proteinases. The cartilage with less water is less resistant to wear and tear. The cartilage with less water is less resistant to wear and tear. Cycle of destruction starts Cycle of destruction starts Compensatory bone overgrowth occurs - subchondral bone increases in density Compensatory bone overgrowth occurs - subchondral bone increases in density

Left: View of normal elbow cartilage through an arthroscope - white, glistening, smooth Right: severe elbow osteoarthritis - cartilage is lost and the bone underneath is exposed

The process cont’d Bony proliferations at joint margins form, osteophytes Bony proliferations at joint margins form, osteophytes Thought to be new bone formation in response to degenerating cartilage Thought to be new bone formation in response to degenerating cartilage They cause joint motion restriction They cause joint motion restriction

What to look for in an x-ray Radiographic changes visible relatively late in the disease Radiographic changes visible relatively late in the disease Subchondral sclerosis Subchondral sclerosis Joint space narrowing esp where there is stress Joint space narrowing esp where there is stress Subchondral cysts Subchondral cysts Osteophytes Osteophytes Bone mineralization should be normal Bone mineralization should be normal

Joint space narrowing where there is more stress Joint space narrowing where there is more stress Subchondral bone has thickened Subchondral bone has thickened bony overgrowth bony overgrowth

significant joint space narrowing as well as proliferative bone formation around the femoral neck (arrows)

Left: normal hip Right: There is some joint space medially but the superior portion is completely destroyed. Supralateral aspects affected most because the weight is transfered through the roof of the acetabulum. Note the sclerosis and oseophyte formation (arrow).

painful bone on bone contact at the CMC joint and the large bone spurs -- osteophytes.

X-ray shows lateral osteophytes, varus deformity, narrow joint space in a 70 yr old female with OA

Clinical features and diagnosis Pain PainSources –Joint effusion and stretching of the joint capsule –Torn menisci –Inflammation of periarticular bursae –Periarticular muscle spasm –Psychological factors Deep, aching localized to the joint Deep, aching localized to the joint Slow in onset Slow in onset Worsened with activity in initial stages Worsened with activity in initial stages Occurs at rest with advanced disease Occurs at rest with advanced disease

May be referred eg hip pain referred to the thigh, groin, knee. May be referred eg hip pain referred to the thigh, groin, knee. Pain may be aggravated with weather changes Pain may be aggravated with weather changes

Exam Joint line tenderness Joint line tenderness Bony enlargement of joint Bony enlargement of joint +/- effusion +/- effusion Crepitus Crepitus Decreased range of motion Decreased range of motion

Joint exam Joint line pain can indicate tear of the lining of the capsule or the meniscus. Joint line pain can indicate tear of the lining of the capsule or the meniscus.

Joint exam In the evaluation of joint line pain, perform a varus or valgus stress test. In the evaluation of joint line pain, perform a varus or valgus stress test.varusvalgus stress testvarusvalgus stress test Apply stress across the joint, place fingers directly over the joint line to assess for pain, a clunk may indicate a meniscal tear, or crepitus may indicate cartilage damage. Apply stress across the joint, place fingers directly over the joint line to assess for pain, a clunk may indicate a meniscal tear, or crepitus may indicate cartilage damage.meniscal tearmeniscal tear

Have the patient to lie supine on the exam table with leg muscles relaxed Have the patient to lie supine on the exam table with leg muscles relaxed Press the patella downward and quickly release it. Press the patella downward and quickly release it. the patella visibly rebounds. the patella visibly rebounds. This mean a large knee effusion This mean a large knee effusion Called ballotable patella Called ballotable patella

Have the patient lie supine with leg muscles relaxed Have the patient lie supine with leg muscles relaxed Compress the suprapatellar pouch with your thumb, palm, and index finger. Compress the suprapatellar pouch with your thumb, palm, and index finger. "Milk" downward and laterally so that any excess fluid collects on the medial side. "Milk" downward and laterally so that any excess fluid collects on the medial side. Tap gently over the collected fluid and observe the effect on the lateral side Tap gently over the collected fluid and observe the effect on the lateral side A fullness on the lateral side indicates the presence small knee effusion A fullness on the lateral side indicates the presence small knee effusion

Involved joints DIP DIP 1 st carpometacarpal 1 st carpometacarpal cervical/lumbar facet joints cervical/lumbar facet joints 1 st metatarsophalangeal 1 st metatarsophalangeal Hips Hips Knees Knees Uncommon Uncommon Wrist, elbows, shoulders, ankles Wrist, elbows, shoulders, ankles

1 st metatarso-phalangeal most commonly affected in OA of the foot. 1 st metatarso-phalangeal most commonly affected in OA of the foot.

Typical findings Heberden’s nodes Heberden’s nodes Bouchard’s nodes Bouchard’s nodes

Varus deformity of the knee

Treatment Non-pharmacological Non-pharmacological No proven medication-based disease modifying intervention exists. No proven medication-based disease modifying intervention exists. Analgesics (acetominophen/ paracetamol) Analgesics (acetominophen/ paracetamol) NSAIDS NSAIDS Help pain symptoms but controversial for long term use in non-inflammatory OA because of risks vs benefits Help pain symptoms but controversial for long term use in non-inflammatory OA because of risks vs benefits Narcotics Narcotics Intra-articular steroids Intra-articular steroids Chondroprotective agents Chondroprotective agents Anti-depressants Anti-depressants

Non-pharmacological rx Reasonable evidence for efficacy Reasonable evidence for efficacy Exercise – prevent disuse atrophy of muscles Exercise – prevent disuse atrophy of muscles Physical therapy: Hydrotherapy/heat/cold, paraffin baths Physical therapy: Hydrotherapy/heat/cold, paraffin baths Weight loss Weight loss Education Education Wedges shoe insoles/braces Wedges shoe insoles/braces Refer to physiatrist for management plan. Refer to physiatrist for management plan.

Analgesics Paracetamol at doses of up to 4g per day Paracetamol at doses of up to 4g per day

Opioid analgesics Generally should be avoided for long term use Generally should be avoided for long term use For short term rx they may be effective. For short term rx they may be effective. In older pts use caution because of side effects such as confusion, constipation, sedation. In older pts use caution because of side effects such as confusion, constipation, sedation. Can use tramadol with pcm, in addition to NSAID/COX-2 inhibitor Can use tramadol with pcm, in addition to NSAID/COX-2 inhibitor

A controlled study showed codeine and pcm combination to be equivalent to tramadol and pcm A controlled study showed codeine and pcm combination to be equivalent to tramadol and pcm Consider opiates if pt is not a candidate for surgery, or is at high risk for side effects from NSAIDS Consider opiates if pt is not a candidate for surgery, or is at high risk for side effects from NSAIDS

NSAIDS Useful in non-inflammatory OA when pain is moderate to severe Useful in non-inflammatory OA when pain is moderate to severe Topical preparations available Topical preparations available PGE2 may contribute to local inflammation and so there is a role for NSAIDS in inflammatory OA PGE2 may contribute to local inflammation and so there is a role for NSAIDS in inflammatory OA

Selective COX-2 inhibitors They have times selectivity for COX-2 over COX-1. They have times selectivity for COX-2 over COX-1. Less gastroduodenal toxicity Less gastroduodenal toxicity Avoid in pts with atherosclerotic CAD - use traditional NSAIDS with a PPI/sucralfate/misoprostol Avoid in pts with atherosclerotic CAD - use traditional NSAIDS with a PPI/sucralfate/misoprostol

Side effects Rash/hypersensitivity Rash/hypersensitivity GI bleeding GI bleeding CNS dysfunction in elderly CNS dysfunction in elderly Impairment of renal/hepatic/platelet function. Impairment of renal/hepatic/platelet function. How can NSAIDS lead to renal dysfunction? By interfering with vasodilator renal PG and causing renal ischemia. By interfering with vasodilator renal PG and causing renal ischemia.

Intra-articular corticosteroids May be used if NSAIDS are contraindicated, persistent pain despite use of other medications. May be used if NSAIDS are contraindicated, persistent pain despite use of other medications. (not > 2 injections per year per joint) (not > 2 injections per year per joint) saline vs. steroid injection? saline vs. steroid injection? A study comparing the two in knee OA showed no effect on joint space narrowing or significant difference in pain at the end of the study, but over a 2 yr period saline injections has less pain relief. A study comparing the two in knee OA showed no effect on joint space narrowing or significant difference in pain at the end of the study, but over a 2 yr period saline injections has less pain relief.

Intra-articular hyaluronans Evidence shows they have a small advantage in terms of pain control, compared to intra-articular placebos or NSAIDS. Evidence shows they have a small advantage in terms of pain control, compared to intra-articular placebos or NSAIDS. No evidence for improvement in function No evidence for improvement in function Two studies comparing intra-articular steroids to hyaluronans have come to opposite conclusions-more trials are needed. Two studies comparing intra-articular steroids to hyaluronans have come to opposite conclusions-more trials are needed.

Surgical: arthroscopy arthroscopy is not recommended for nonspecific "cleaning of the knee“. arthroscopy is not recommended for nonspecific "cleaning of the knee“. Used to fix specific structural damage on imaging (repairing meniscal tears, removing fragments of torn menisci that are producing symptoms). Used to fix specific structural damage on imaging (repairing meniscal tears, removing fragments of torn menisci that are producing symptoms).

Joint replacement If all other rx ineffective, and pain is severe If all other rx ineffective, and pain is severe Loss of joint function Loss of joint function Joints last 8-15 years without complications Joints last 8-15 years without complications

The end