Arthritis…. And how to manage the older horse Barn talk January 16th 2011

JOINT ANATOMY 2 bones which articulate with each other Both bone ends covered with cartilage Joint capsule Synovial membrane Synovial fluid Collateral ligaments

JOINT ANATOMY A schematic image of a joint: In BLACK the margins of the bone, 2 opposite bones are connected in the joint. In RED the joint capsule, that forms a sack around the joint, keeping the synovial fluid in the joint. In GREEN the collateral ligaments, that keep the joint (tight) together.

Schematic drawings of a joint: view of all the structures

JOINT ANATOMY In this view you can observe in black the collateral ligaments. In the Fetlock Joint only mobility in one plane is possible, only flexion and extension can occur. No movement from side to side.

Cartilage Fetal development, only minor adaptations occur during the first year of life. After the first year of life no regeneration It is a network structure of collagen with very few cells. –proteoaminoglycanes, –hyaluronic acid, –glucosamines, –Sulfur and water No blood vessels, all nutrition from synovial fluid. Insensitivity (no nervous tissue) Cartilage forms a perfect coverage for the hard and dense bone, it is soft, very smooth and has a very high cushioning function.

Cartilage: network of collagen fibers

Cartilage: in (red) hyaluronic acid emerged in the network structure of collagen fibers

Cartilage: incorporation of proteoaminoglycanes (green) and glucosamines (blue) in the network structure

Cartilage: 2 cells (chondrocytes) in the network structure

Capsule Collagen Low elasticity Rather thin (1-3 mm) Vascular and sensitive Inner side (in joint space) layered with synovial membrane Synovial membrane produces fluid with nutrients to support cartilage Does not give much stability to the joint, prevents synovial fluid from leaking out

Collateral ligaments: Very stiff and rigid collagen with very low elasticity Attached to bone Very low level of metabolism Support joint in mobility in specific directions, stabilizes joint in other directions

Primary Injury Most injuries to a joint start with an injury of the ligamentous structures of the joint. When the injury is not given time to heal more mobility in the joint will occur. Due to mobility in an unnatural direction, more wear and tear changes of the cartilage are present, resulting in an advanced degree of aging and damaging of the joint

Injury of collateral ligaments: Tear and loss of fibrous architecture Loss of elasticity More mobility Tear and irritation of the attachment of the ligament at the bone and periostium Release of cytokines and prostaglandines

When collateral ligaments are overextended, less stabilization is achieved and the joint has mobility in an unnatural direction

Injury of the capsule: Results from an instability of the joint Tear of the collagen architecture Release of cytokines and prostaglandines Higher vascular perfusion More synovial fluid, lower concentration of nutrients in synovial fluid

Release of prostaglandines and leucotriens in synovial fluid Damage of cartilage due to action of prostaglandines and leucotriens

Injury of cartilage: Damage to the cartilage network structure Release of compounds of cartilage Release of cytokines and prostaglandines Dissolving of the network structure Desintegration of the compounds of cartilage as hyaluronic acid, proteoaminoglycanes and glucosamines

Cartilage: (note: 2 cartilage cells; chondrocytes)

Primary injury: damage of network structure and one chondrocyt

Release of cytokines and prostaglandines

Cytokines and prostaglandines induce dissolving of more of the network structure of cartilage

White blood cell attracted by cytokines and prostaglandines

White blood cell dissolves all affected cartilage

Collagen forming cell appears and makes bedding for new network structure

New network structure formed, less dense and of other origin than original network structure

Incorporation of compounds in new network structure; “scar- tissue” with cartilage-like appearance

Inflammation of the joint; inflammation of the capsule; capsulitis and inflammation of the synovial membrane; synovitis, inflammation of the collateral ligaments; desmitis.

Synovitis/capsulitis: Inflammation of joint’s soft tissues Reversible! For healing essential: take away primary cause (OCD, ligament damage, training issues)

Arthritis: Damage to cartilage Repair of cartilage: scar tissue No healing possible; just “management” Normal aging process!

Medication: Anti-inflammatory (pain management) Chondroprotective Preventive/maintenance New stuff…

Anti-inflammatory: Non Steroidal Anti-inflammatory Drugs (NSAID’s): Block production of inflammation mediators (Prostaglandin,cytokines) Systemic use (oral, injection) Side effects (gastrointestinal) Phenylbutazone, Equiox®, Naproxen®, Banamine®, Aspirin®, etc…

Anti-inflammatory: Local application of NSAID: Surpass® Less side effects

Anti-inflammatory: Steroidal drugs: corticosteroids: Inhibit production of inflammation mediators, stabilize cell membranes, reduce white blood cell activity (lower immunity *) Very strong: lots of side effects Depomedrol, triamcinolone, betamethasone

Chondroprotective: Protect cartilage Regenerate cartilage? Mild anti inflammatory…. In early stages of inflammation

Chondroprotective: Injectable: Hyaluronic acid (Legend®), PAG (Adequan®), In muscle or vene In joint…

Chondroprotective: Oral: Supplements/neutraceuticals No scientific proof of action in horse 79% of the products lower levels than on label (new: ASU)

“New”… IRAP (interleukine Receptor Antagonist Protein), Conditioned Autologous Serum (CAS) Processed blood product; “soup”, contains “natural” inflammatory substances.

“New”… Experimental: Conditioned autologous cartilage cells: Harvested, processed and adhered to damaged joint surface Combinations of stem cells and PRP

Treatment: Synovitis/capsulitis: anti-inflammatory: NSAIDs, cortico’s, cold-therapy, reduced work! Arthritis: management of inflammation; NSAID’s, cortico’s, “Arthritis-regime” work

Arthritis-regime: Gradual increase of work Daily work, regular work Period of warm-up and cool-down Lowest medication possible Attention to temperature Attention to behavior Joint injections!

Diagnosis: Need to have staging: synovitis/capsulitis/arthritis Complete diagnosis: soft tissue condition Evaluation of level of arthritis: X-ray, US and NM…(MRI) Effective treatment at minimal effective level

Joint injections: Proper diagnosis: Soft tissue: reduce work load (HA, cortico’s, NSAID’s) Arthritis: continued work load, cortico’s, NSAID’s, IRAP Realize the joint is injected!

Prevention: Early detection! Most joint injuries are soft tissue injuries! Treatment in this stage is very effective, complete healing possible When chronic joint changes are present: management, no healing

Early detection: Symptoms: Changed behavior Subtle lameness Reduced range of motion in the joint, stiffness “horse feels different”

Early detection: Some days off, NO PASTURE Stall rest and hand walk days 3-5 times a day on hard surface for min. Try again: better? Gradually increase of work load

Early detection: Not better: get the vet out! Diagnosis before treatment! Localize problem, imaging techniques to evaluate structures involved (X-ray, US, bone scan, MRI, CT) Treatment and/or medication

Prevention: Regular work Daily work…. Gradually increase work load…

Prevention: Avoid clear dangers…. Slippery footing Horses out in pasture when they are used to it.. Not when loaded with energy for short turnout..

The aging horse: Wear and tear on the joints Maintain maximum range of motion No overstretching/flexing Regular work Gymnastic exercises

Supplements: When you feel your horse needs it In people: 65% feels better with placebo, medication and/or supplement…

Daily work out: Warm up (5-10 minutes) Walk, trot. Flexing, stretching and in frame Tests for symmetry

Daily work out: Main course of training episode: Shorter, brief episodes of intense work Periods of relaxation minutes

Daily work out: Cool down 5-10 minutes Walk and trot Hard surface Outside…

Center update: Ultrasound and digital X-ray available! Website up this month! Performance check-ups very successful Clinics in Holland and Metamora Collaboration with MSU

Next barn talk: Somewhere in March: Horse behavior: when is it behavioral and when is the horse in pain? How to deal with common behavior issues