Bone Spavin

Bone Spavin – Understanding it and treating it!


Horses that have bone spavin may present to the vet as an obvious lameness or just as a horse that doesn’t feel right when ridden.  It is important that a thorough work up is performed to obtain a correct diagnosis of bone spavin.



Clinical Examination

The vet will give the horse a thorough clinical examination including palpating, lifting and manipulating all limbs.  We will then see the horse both walk and trot in a straight line and on the lunge to diagnose any lameness evident at this point. Flexion tests will be performed which involves holding the leg up in a flexed position for a minute before trotting off in a straight line.  Horses with bone spavin will often have an increased level of lameness when this is performed.


Joint Block

A procedure called intra-articular anaesthesia (joint block) of the tarso-meta tarssal joint on the affected limb will be performed.  This involves injecting local anaesthetic under aseptic conditions into the lowest of the hock joints. This is a low motion joint in the hock but a common site for arthritis.  Horses with bone spavin will show an improvement in the level of lameness with this procedure.



Radiographs (xrays) are then taken often of both legs to allow a comparison is necessary.  Our digital xray machine is mobile so this can all be performed at your yard without the need for any travelling.

Below are some radiographs of hocks with bone spavin.


Xray bone spavin Xray bone spavin 2
These X-rays are the same view of both hocks comparing one leg with the other. Both lower joints are affected on the right image showing osteolytic changes (bone being eaten away giving a lighter, fluffier appearance to the bone) and joint narrowing in particular of the tarso-metatarsal joint.
xray bone spavin 3
This is a close up of the joints of the right hock showing evidence of bone spavin in the lower two joints.

The combined results of the clinical examination, joint block and radiographs can allow the diagnosis of bone spavin


This is osteoarthritis of the lower hock joints. It is responsible for approximately 1/3 hind-limb lameness that is seen in horses and it therefore important that we understand the condition and treat it in the most suitable way.


Some of the bony changes that are seen on radiographs of horses with bone spavin include bony spurs, new bone formation, bony destruction and/or joint narrowing. One or more of these changes can be seen from animal to animal. The extent of the bony changes does not always correlate with the degree of pain seen.



  1. Pain relief and exercise

The idea behind this is that it encourages fusion of the lower hock joints. The reality of the situation is that they can take years to fuse.


  1. Joint medication

There is well documented research that medicating joints with steroids has a direct anti-inflammatory effect within the joint. The effects can be short lived or they can last indefinitely.


  1. Osphos

Osphos is an intramuscular injection so is much easier to administer than Equidronate. Osphos contains the bisphosphonate Clodronic acid which inhibits resorption in the navicular bone by binding to hydroxyapatite crystals and by direct cellular effects on osteoclasts.  Whilst licensed for treatment of navicular disease it is beneficial in the treatment of bone spavin.


  1. Equidronate infusion

Equidronate (formally known as Tildren) is a licensed treatment to treat bone spavin in horses in the UK. In simple terms it downregulates the bone eating cells (osteoclasts) and allows the bone producing cells (osteoblasts) to repair the problem.  Equidronate is administered by giving a one litre fluid solution via a drip directly into the horse’s vein over 45-60 minutes. An occasional side effect is showing signs of spasmodic colic so the horse is monitored throughout administration and given an anti-inflammotory prior to administration


  1. Cartrophen injections

Cartrophen can be given to treat arthritis in horses. It can provide relief from pain, stiffness and lameness as effectively as NSAIDs like Bute. Normally a course of 4 injections is given once a week into the muscle. The beneficial effects can usually start to be seen by the second or third injection.


  1. Remedial Farriery

Sometimes a farrier may shoe a horse with bone spavin in a different way. This can include the use of lateral extensions on the shoe to prevent the leg from twisting.