Everything Horse magazine Everything Horse UK Magazine, November 2014 | Page 22

HEALTH: THE LOCKING STIFLE Bowen Therapy A Common problem ... Upward fixation of the patella known as ‘locking’ stifle Upward fixation of the patella is a normal function of the horse, and it is this ability to ‘lock’ that allows the horse to sleep standing up with very little muscular strain. It becomes an abnormal function when locking of the joint occurs unintentionally. Locking stifle can occur in any horse or pony or any age or breed, but it is most commonly seen in our four legged friends that have very upright hind legs. The reason for this is because the problem is a temporarily fixed in an extended upright (straightened) position. So inevitably those horses with upright hind limbs are at a greater risk. Clinical signs This can be seen at rest or during work. The horse may be walking along and suddenly the hind limb in question may be momentarily fixed in extension, often the horse can hop or stretch out the limb and it will pop loose in many horses. It has been known in severe cases to need veterinary assistance to release. When this happens the hind leg will be extended out behind and the horse cannot bring it back into the normal position. Image credit Mike Bain The locking stifle The Stifle; the large joint between the femur and the tibia - comparable to the human knee The science of the ‘normal’ hind leg For the horse to move and simply protract the limb (the foot to lift off the ground, brought under the body and placed back on the ground) requires several joints to work in unison. The hip, hock and stifle work together to create resistance in its state of motion, to maintain speed and direction in a straight line at constant velocity. The aim of the leg is to move with the least amount of muscular work. For the limb to glide through the air in a smooth easy motion several muscles and tendons have to work in harmony, some contract while some extend. This simply means that the stifle and hock are constrained to operate as a unit when the foot is off the ground. A result of this is that the hip, stifle and fetlock will all 22 operate and flex alongside one another. You can try this for yourself by lifting your horse’s leg. The reason this occurs is because the limb is tied together by the same tendinous fibres which acts as a bungee/strap. point which allows us to divide the joint into two separate sections, the medial (towards the midline) and lateral (towards the back) aspect. There is also a ‘bumpy’ ridge at the front of the joint known as the tibial crest. Structure and function Next we will look at the femur, the bone that connects to the hip and the stifle. The base of the femur, making up part of the stifle joint has two round projections which we call condyles; a larger medial condyle and a smaller lateral condyle. Between these two heads is a shallow groove known as the trochlear groove. This groove is there for the patella to glide up and down. Finally we have the patella – this is a small triangular bone that is surrounded mostly by cartilage and tendon of which help to anchor it in place. The stifle is a fairly complex joint and it is important to understand its function in a normal state before we can look at it in an abnormal state. The stifle consists of three bones, the femur, tibia and patella. If we compare it to a human knee: the tibia is the shin bone, the femur is the thigh bone and the patella is the knee cap. Let me try and explain; the upper end of the tibia (the shin) has a bony spike or Everything Horse UK Magazine • Issue 14 • November 2014 It is the action of the patella sliding up on to the trochlear groove at the end of the femur - when the ligament and patella slide up too far then they will hook itself and get caught on the condyle of the femur. The result is that the stifle joint is fixed and locked in to the position. When this action happens repeatedly, often the medial patellar ligament may have been stretched making it more of a risk of catching. However it could also result from medial patellar ligament stretch. Factors that can affect this... As already discussed this can be a result of an upright limb, it could be hereditary – but often not directly – in the sense that the genetics will play a part in conformation. • It can be through injury or extreme force on the joint • Kicking and getting the leg caught in a fence • It can affect show jumpers • Mares that were put into foal too young – it can compromise their • • • own structure and nutritional requirements while carrying a foetus. It can also affect horse that is malnourished Lack of muscle tone, or even horses that have restricted movement and lack of exercise. The quadriceps muscles put constant tension through the ligaments surrounding the patella, loss of tone and nourishment will have a knock on effect of the remainder soft tissue. Proper nutrition using pure herbs of a good quality and grade will help enormously. However this does not answer the question as to why extremely fit horses suffer from this condition. In these circumstances I would look into greater depth; the obvious firstly – nutrition, quality of the hoof and angle of the trim, how the horses hoof is landing and any other soft tissue tension. I would be looking into detail about the daily routine of the horse – does the horse work extremely hard then is left in a stable for long periods of time? This can affect the blood flow to the areas! High levels of exercise require more nutrients and oxygen to the musculature and at rest this can then be restricted if left standing still for long periods. Locking stifles can be more pronounced when working in deep material like sand, but also work on a circle (lunging) or walking downhill increases the load on the affected stifle. Corrective management This will vary enormously depending on the individual horse, its work load, diet, environment and duration that it has been suffering. The tailored program for each horse will also depend on the initial cause. In any case it is vital to assess the nutritional requirements of the horse and make sure they are being met, make sure the horse has regular exercise if it is unfit or lacks muscle tone – avoiding tight circles, lunging, deep sand and steep hills. For those horses that are confined to a stable is it important they get regular in- hand walks for at least 20 minutes two or three times a day if they have no turn out. November 2014 • Issue 14 • Everything Horse UK Magazine Training – How can you help your horse? Equine Smart Bowen training is now available for the first time in the UK. Starting in spring 2014, whether you want to be a practitioner – and change your career or you want to learn to help your own horse. Training will be available at reasonable prices. You can have small groups or even one –to-one training if you prefer. Contact Information Please feel free to contact me about anything I have written in this article – and again please remember if in doubt call your local vet to assess anything that is of concern to you. This article is for interest only. Treatment and further information Lindsay Holder – UK practitioner and trainer 07703010044 lindsay@lindsaybowentherapy. co.uk [email protected] www.lindsay-bowentherapy.co.uk www.smartbowen.com “Locking stifles can be more pronounced when working in deep material like sand, but also work on a circle (lunging) or walking downhill increases the load on the affected stifle” 23