These are a point of reference for the clinician and are not definitive
PAAG products, although often considered equal, have clear differences in composition, manufacturing and injection techniques as well as their ability to interact with surrounding tissues. Characteristics that determine the safety and effectiveness of each hydrogel.
Upon injection into joints, the Arthramid® Vet , a uniquely cross-linked 2.5% polyacrylamide hydrogel, adheres to the synovial lining through its ability to exchange water molecules. This immediately reduces exposure of synoviocytes to pro-inflammatory cytokines in the inflamed or diseased joint. Over a period of 14 days the gel becomes integrated into the synovial lining and its immediate surrounding tissue of the inner capsule by a combination of cell migration and vessel ingrowth forming a thick, cushion-like membrane consisting of vessel integrated gel covered by a new and hypercellular synovial cell lining.
As a result Arthramid® Vet has an augmentation effect on both the joint capsule and synovium. It increases the elasticity and tensile strength of the capsule improving its capacity to transfer load. It is believed that this augmentation and cushioning causes a subsequent reduction in mechanoreceptor activation in the capsule itself. It also causes the formation of a new and hypercellular synovial cell lining improving the quality of synovial fluid within the joint itself. These actions both help reduce synovitis and its successively deleterious effects as a result.
Unlike other hydrogels Arthramid® Vet becomes fully integrated into the surrounding tissue (rather than encapsulated) and is therefore long lasting. Arthramid® Vet does not elicit a foreign body reaction or harbour infection. Arthramid® Vet is non-pyrogenic and neuro-innocuous.
Understanding the complexity of disease processes associated with joint pain remains a constant dilemma in clinical practice and as with any disease process, an accurate diagnosis is essential.
Arthritis describes inflammation of a joint and can occur after single or repetitive episodes of trauma. The term incorporates synovitis, capsulitis, sprain, intra-articular fractures, meniscal tears and osteoarthritis(OA). Sub-chondral bone injury also plays a role.
These pathological conditions are ‘a group of overlapping distinct diseases which may have different aetiologies, but with similar biologic, morphologic, and clinical outcomes.’
Although conventional concepts of OA emphasize the direct and predominant involvement of cartilage and bone in OA development, it is increasingly recognized that the synovium also contributes to the central pathophysiological event of cartilage matrix depletion.
Cases suitable for treatment with Arthramid Vet are those in which lameness is localised to the joint by clinical examination, intra-articular analgesia, radiography, ultrasound, MRI, CT and/or Scintigraphy. Conditions that respond to treatment with Arthramid Vet include acute and chronic synovitis, capsulitis, meniscal tears, OA and subchondral bone cysts. It is essential that anamnesis of data of ongoing infection, concomitant medication, surgery or potential fracture is reviewed prior to injection to prevent possible infections or use of the product for conditions other than for which it is indicated.
The owner of the animal should be informed about the indications, expected results, contraindications, precautions, warnings and potential complications. The owner of the animal should be advised that in case of complications the veterinarian, who performed the Arthramid® Vet injections should be contacted immediately for necessary treatment.
Arthramid® Vet is for intra-articular use only and must be administered by a qualified veterinarian familiar with the procedure in the intended species. Animals may be sedated to minimize stress and discomfort. Strict aseptic conditions must be followed at all times.
A 20G to 23G needle is placed intra-articularly. Synovial fluid should be observed. Care should be taken to avoid unnecessary damage of the intra-articular tissue, as this may result in diffuse swelling lasting for 24 to 48 hours. Remove the protective tip cap from the Arthramid® Vet syringe. Attach the syringe firmly into the Luer lock socket on the needle. Make sure the syringe is correctly mounted. The amount of Arthramid® Vet used is 1 – 4 mL. If necessary, attach a new Arthramid® Vet syringe during the procedure and continue the injection.
Due to Arthramid® Vets’ unique mode of action the following dosage recommendations have been made based on observed clinical responses to treatment;
• Distal Interphalangeal (DIP/ Coffin)- 1-2 mls
• Metacarpo/tarso-phalangeal (Fetlock)- 2 mls
• Carpus- 2mls
• Tarso-metatarsal (TMT)/ Distal-intertarsal (DIT)- 1 ml
• Tarsocrural- 2-3 mls
• Shoulder- 3 mls
• Stifles- 1-2 ml per compartment or 3-4mls for medial-femorotibial joint
Published clinical trials indicate horses that partially respond to an initial treatment may benefit from a second dose at 4 to 6 weeks later.
Safety Studies indicate that concurrent treatment of multiple joints in the same animal is safe.
An ointment can be applied on the injection site immediately after treatment. A cold pack can be applied on the injection site in case of an oedema. A bandage can be applied around the injection site if possible. Local or systemic corticosteroids should not be administered to the animal within two weeks of injection of Arthramid® Vet since this may mask a possible infection. The animal should be rested for 48 hours after the treatment.
Some animals can develop pain within the first few hours post- administration. In addition, there is also a slight risk of haematoma and mild oedema at the site of injection. Within 1-2 weeks after treatment there is a slight risk that the animal may develop a transient oedema and tenderness at the treatment site as the tissue integration is occurring. If not caused by infection, these reactions are self-limiting and will resolve within a couple of weeks. Non-steroidal anti-inflammatory drugs (NSAIDs) can be administered for pain relief and to reduce swelling. Allergic reactions to Arthramid® Vet have never been observed.
As with any intra-articular procedure, an Arthramid® Vet injection carries a risk of infection. Standard precautions and strict aseptic injection technique is essential. In the event of infection, the use of broad spectrum antibiotics is recommended as a first line treatment. Any use of corticosteroids is contraindicated in case of infection.
Following treatment animals should be rested for 48 hours. After this time the animal can return to low impact exercise and until a response to treatment is seen- typically 2-4 weeks after treatment.
Clinical studies show that tissue integration and subsequent augmentation of the joint capsule takes between 2 and 4 weeks to occur, although a response to treatment can be seen earlier than that in some cases.
Animals typically show a gradual reduction in lameness during the first week after treatment and a concurrent reduction in reaction to passive flexion. This continues to improve over the ensuing weeks. By 4 to 6 weeks no further improvement is expected. Re-examination at 4 to 6 weeks is therefore indicated to either administer a second dose - in those that have only partially responded- or to reassess accuracy of the diagnosis.
It is important for owners to understand the time lag for a treatment effect to be seen as this contrasts with conventional therapies. In this respect and due to its long lasting effect it may also be prudent to consider treating the animal during periods of reduced exercise demands or early on in the animals training programme.
Arthramid ® Vet must be stored below 25°C (air conditioning) protected from direct sunlight. Do not freeze. Do not store unsealed syringes for later use.