Knee OA

Non Operative Management

 

Options / ELM POPI

 

Education

Lifestyle Management

- weight loss

- reduce sport

Physiotherapy

Orthotics

- walking stick

- braces

Pharmaceuticals

- NSAIDS

- acetominophen

- glucosamine

Injections

- cortisone

- hyaluronic acid

 

Definition OA

 

Loss of integrity of the articular cartilage

 

Outerbridge Grading

 

I   Fibrillation

II  Fragmentation < 1/2 depth

III Fragmentation > 1/2 depth

IV  Erosion to bone

 

Investigations

 

Rosenberg view / tunnel view

- 45o flexion weight bearing view

 

Rosenberg View

 

Rationale

- most early cartilage loss is in 30-60o flexion range

- can be missed with view in extension

 

Knee OA APKnee OA Rosen View

 

Glucosamine

 

Action

- stimulates proteoglycan synthesis by chondrocytes 

- has mild anti-inflammatory properties

- however, therapeutics seems to be via PG independent mechanism

 

Results

 

Several clinical trials in patients with OA

- superior results with glucosamine sulfate compared to placebo

- reduced incidence of adverse effects

 

JBJS Am 2000

- meta-analysis

- glucosamine and chondroitin are effective for improving outcomes

- the magnitude of effect is unclear because of inconsistencies in study design

- dependence on industry support for study execution

 

Advantage

- harmless

 

Disadvantage

- reasonably expensive

- $30 / month

 

Reasonable to trial and continue if works

 

Hylan Injections / Viscosupplementation

 

Compound

 

Hylans are cross linked molecules of Hyaluronan

- derived from rooster combs or newer synthetic compounds

 

80% hydrate Hylan A

- water soluble molecule of approximately 6 million MW

- a marked increase in elastoviscosity compared to hyaluronan

 

20% hydrated Hylan B

- a solid derivative with continuous cross-linking between all the constituent molecules

- forms a more stable, highly elastic hydrated molecule

 

Options

 

Synvisc

- 3 x doses

 

Durolane

- synthetic

- single dose

 

Cost

 

$4 - 500 per treatment

 

Rationale

 

In inflamed joint

- decreased concentration and MW of hyaluronan

- stimulates inflammation

 

OA

- synovial fluid significantly reduced viscoelasticity

- synvisc replaces the pathological synovial fluid

- supplementing elasticity and viscosity thereby reducing pain and improving mobility

 

In vitro effects

- cell migration and phagocytosis slowed down or inhibited in elastoviscous environment

- nociceptors also sensitive to visco-elastic state

- high MW hyaluronan also decreases concentration of bradykinins etc

 

Results

 

Wobig Clin Ther 1998

- 57 knees 3 x 2ml injections each 1 week apart

- vs 60 knees saline injection

- 12 week end point

- X rays grade II-III

- 40% better pain relief in control

- 82% better pain relief in synvisc

 

Bellamy et al Cochrane Review

- evidence supports use of HA injection in knee OA

 

Complications

 

1% risk of acute allergic reaction

- sudden swelling and pain

- treat with cortisone injection

 

Technique

 

Patient with Grade 2/3 OA

- trial injection

- no sport / high impact activities for a few days

- takes 2 weeks to work

- needs to get 6 - 9 months of improvment to repear

 

Weight loss

 

Wt loss > 5 kg in women halves risk of degenerative OA by 50%

 

Physiotherapy

 

Quadriceps rehab shown to improve function without worsening arthritic symptoms

 

Walking Stick

 

Cane in the opposite hand decreases weight bearing load by 30 - 60%

 

Braces

 

1.  Compressive

- neoprene

- provide warmth

 

2.  Supportive

- hinged brace (varus-valgus)

- ACL brace

- PF braces

 

3.  Unloading

- unloading varus knees

- 3 or 5o

- expensive / need to be correctly fitted

- doesn't work on large obese knees due to fitting issues

- shown to decrease pain 

 

Knee Unloader Brace 3 Degree

 

Orthotics

 

Lateral heel wedge for varus knee

- shown to decrease pain in 50% patients

 

Arthroscopic Lavage 

 

Mechanism

 

Unclear

 

1.  Removal "Chemical Soup"

- cartilage debris

- crystals

- inflammatory factors

 

2.  Able to treat internal derangement at same time

- chondral flaps

- meniscal tears

 

Indications

 

A.  To postpone TKR

- young, mild OA, no malalignment

- loose bodies

- mechanical symptoms

- recent effusion

 

B.  Want to establish patient has severe enough OA to warrant TKR that you cannot see on X-ray

- staging OA

- HTO v TKR

 

Results

 

Kirkley et al N Eng J Med 2008

- RCT of moderate to severe OA

- arthroscopic lavage and debridement v physiotherapy / medical therapy only

- no difference in outcome

 

Herrlin et al Knee Surg Sports 2007

- randomised patients with degenerative / non traumatic medial meniscal tears

- arthroscopic debridement v exercise program

- no difference in two groups