Arthritis and pain management

Mark Tabachnik BSc BVM&S Cert EP MRCVS

Wright and Morten

Aims of this talk

• The normal joint• The abnormal joint• Treatments (1) the diseased joint• Treatments (2) the painful horse

– Painkillers– Supplements– Management techniques

• Particular examples – – Bone Spavin– Ringbone– Too painful to rise

The normal joint

• Union between two bones (“synovial”)

• Bone, cartilage & soft tissues

• Virtually frictionless gliding surface

• Large contact area allows normal range of motion

• Stability provided by ligament / capsular tissue

The normal joint

anatomy

bone

Joint capsulemembrane

Joint fluid

cartilage

bone

• Subchondral bone – layer of bone under cartilage

• Spongy, springy, deformable (you’ll see why later)

Articular cartilage

• Covers bone plate, to which it is firmly attached

• No blood supply, nutrition from diffusion via synovial fluid

• 2% cells

• 80% water (decreases with age)

• Collagens and other proteins

The normal joint

anatomy

bone

Joint capsulemembrane

Joint fluid

cartilage

Structure of cartilage

bone

collagen

Structure of cartilage

HA

GAGs

Proteins

• Hyaluronic acid (HA)

• Glycosaminoglycans (GAGs)

• Kerratin sulphate, chondroitin sulphate

• highly negative charged – bind up to 50x weight in water

• Matrix of high tension holding in large amounts of water

Structure of cartilage

HA

GAGs

cells

• Chondrocytes (“cartilage cells”)

• Make collagens and proteins

• But can produce enzymes and destroy them too

• Natural turnover of matrix – fast for proteins, slow for collagen

Synovial fluid

• Nourishes cartilage

• Lubricates joint – easy frictionless glide of cartilage

• Like blood, but without the cells

The joint in action

• Huge forces run through joint. Cartilage matrix absorbs load.

• Mechanical strength maintained by collagen

• Cartilage squeezed. Rapid movement of water out of matrix into synovial fluid

• Rest of force running through oriented fibres of underlying bone

Like this…………

Force……

Water squeezed out

Force transmitted through bone

The abnormal joint

• Arthritis, Degenerative Joint Disease

• Loss of articular cartilage

• New bone forms at joint margins

• Two mechanisms –

• 1. Cells are injured releasing enzymes that breakdown the collagen and GAGs

• 2.microfractures in bone – increased stiffness

destruction of cartilage

Signs of joint disease

• Pain – nerve supply to joint capsule, ligament, bone. Not cartilage!

• Joint swells (“effusion”) – painful

• Reduced range of motion, guarding joint

• Soft tissues lose elasticity and thicken

Signs of joint disease

• Lame.

• X-ray changes

Treatments (1) the diseased joint

• Injections into the joint get right to the site of disease.

• Corticosteroids – very powerful painkillers» Mode of action?

» Stopping cells releasing enzymes?

» Work for 6wks – 6mo

» Less effective over rpt treatments

Treatment(1) the diseased joint

• HA or PSGAGs

• normal constituent of cartliage

• Lubricant in synovial fluid

• Decrease enzymes, protects cartilage

• Antiinflammatory, painkiller

• Inject directly into joint, or intravenous

Joint injections

• Sterile, surgical skin preparation

• Surgeon gloved up• There’s a small risk of

introducing infection…

Injectable GAGs

• Cartrophen (intramuscular)• Pentosan phosphate (a GAG)• Once a week for 4 weeks

• Adequan (intramuscular)• A GAG• 7 injections, one every 4 days

• Hyonate (intravenous)• HA• Once a week for three weeks

Treatment (2) – the painful horse

• Phenylbutazone

• Well known,

• cheap,effective, fairly safe

• Antiinflammatory, painkiller,

• protects cartilage

• Long term – kidney damage,

• stomach ulcers

• Suxibutazone (Danilon Equidos) – safer?

• Note – is he intended for human consumption?

• Oral corticosteroids

• Prednisolone, dexamethasone

• Good anti-inflammatories, painkillers

• Depresses immune system

• Laminitis risk

Oral supplements

• Many are available

• Chondroitin sulphate

• Glucosamine

• Both are building blocks of GAGs

• Absorbed through intestines and go to joints

• But are they?

• Do they actually work?

• Glucosamine - pick products on purity (99%), and salt type (hydrochloride not sulphate)

• Newmarket Joint Supplement

• Synequin, Cosequin, Cortaflex

• Remember price is important!

Other supplements

• MSM / Sulphur – use?

• Devil’s Claw - herbal painkiller

• Read the label. What is the active ingredient?

• Be careful what you buy, some supplements claim unlikely benefits

• Many supplements do not contain what they say on the label – use one accredited by Soil Association or UKASTA

Feed supplements

• Feed supplements

• Broad spectrum nutrients (~50)

• Biotin,methionine,

• magnesuim,chromium, zinc

• antioxidants

• lysine, threonine.

Acupuncture

• Chinese Meridians (energy channels)

• Good pain relief technique

• Small needles into specific locations

• Weekly sessions then monthly

Management techniques

• Exercise – keep active to improve joint mobility

• Box rest – undesirable. Stiffen up• Moderate slow paced work, less tight

circles, jumping.• Regular, routine• Regular foot care, shoeing• Physiotherapy – warm up, stretching, poles.

Specific lameness examples

• Bone spavin

• Ringbone

• An old horse having trouble standing up

Bone spavin

• Degenerative joint disease of the small hock joints.

• Chronic lameness esp. in trot

• Worse on flexion tests

• Reluctant to trot, jump

Bone spavin – X Ray changes

Bone spavin - treatments

• Steroid injections into small hock joints

• Work on / long term painkillers

• Surgery

Tildren infusions

• New treatment, Tiludronate• “osteoclast inhibitor” – normalises normal bone

turnover• Infusion into vein.• A bit colicy?• Repeated after 6wks or 6mo• Spavin, navicular, ringbone• Does it work?

Ringbone

• Arthritis of the pastern joint

• Side bone = lateral cartilages turn to bone

• Hard to inject joint

Ringbone - treatments

• Rest, painkillers, Cartrophen, glucosamine

• Good shoeing / foot balance

• Tildren infusions

Failure to stand up

• A serious problem of the old horse• struggle, thrash about• Distressing, painful, self inflicted injuries• Arthritis, of what?• Any painful joint long term can cause this

problem, hocks, stifles, hips. • Also back pain• Other problems – heart, nervous system, weakness

etc

• Horses down too long get pins and needles, can’t feel leg

• Painkillers, turn over

• Assisted rise

Long term…

• Keep mobile

• Painkillers

• Acupuncture, physiotherapy

• Euthanasia? Horses repeatedly failing to rise, getting cast and distressed

conclusions

• Degenerative joint disease is an inevitable consequence of wear and tear on an old horse’s joints

• There are a lot of choices for both treatment and management

• “bute” is a good drug, cheap, effective and relatively safe

• For other supplements, be careful what you buy, and read the label!