11 Orthopaedics Like all treatments the clinician needs a history, followed by an examination, in order to make a diagnosis. The treatment plan can then be designed. Any history should obviously include the age of the animal and the work it is doing. Enquires should be made into any previous lameness or injury. The length of the current lameness and whether it had a sudden onset should also be discussed. Was the onset injury related? The leg that the owner considers to be the problem should be recorded. A general examination should be made, which need not be prolonged. However, it is vital that the general health status of the animal and its general demeanour is assessed. Its stance and any muscle wasting should be noted. The animal should be checked for any wounds or infected areas, and any swellings noted. The animal should be walked in a straight line away from and back towards the clinician, and any change in gait discussed with the owner. The animal is then led round in a 5-m circle to both the left and the right. If no severe lameness is noted the animal should be trotted in a straight line. Hopefully, agreement will be reached between the clinician and the owner as to which leg the animal is actually lame on. Great care should be taken to make sure that the animal is lame on only one leg, and that two or more legs are not involved. It may be decided to carry out these flexion tests again with the horse lunged in a circle; perhaps the horse may be examined on different surfaces and lunged on various surfaces. It may be decided to canter the horse as well as just trotting it. It may even be decided to have the horse pull a vehicle to further evaluate the lameness. It should be remembered that this careful examination does not require any sophisticated equipment and can be carried out in nearly all circumstances. However, there can be problems; some horses, particularly very small ponies, will not trot. Other horses, e.g. pacers and Icelandic horses, have a fifth gait and may also be reluctant to trot. Practitioners need always to keep an open mind, but should concentrate initially on the common conditions. A large percentage of lameness cases are related to the foot, the most common being the so-called ‘pus in the foot’. It is rare in cases of ‘pus in the foot’ that some pain is not seen on hoof testing. Conditions affecting the foot of the horse are described in detail in Chapter 10. If a preliminary diagnosis is made there is a large benefit to the animal on welfare grounds if treatment can be initiated immediately. To give an example, a horse may have pastern dermatitis, a condition described fully in Section 19.19. If this condition is even moderately severe it will cause lameness. Equally, the clinician may be concerned that there is an underlying cause of the lameness as well as pastern dermatitis, which may be on several limbs. It is therefore logical to treat the pastern dermatitis and cure, if possible, that condition before going on with a more intensive lameness investigation. 1. Non-steroidal anti-inflammatory drugs (NSAIDs; see Section 5.8). These must be injected i/v. Those used in equines are phenylbutazone (PBZ), flunixin, ketoprophen, meloxicam and carprophen. This can then be followed up in oral form, either as an oral paste in the case of PBZ and flunixin or as a powder for them all. Aspirin, the oldest known NSAID, is available as a powder. Large doses of aspirin, e.g. up to 100 mg/kg, are often required before any effect is seen. 2. Chondroprotection nutrichemicals. There are very few double-blind trials for these chemicals. They are expensive and have exaggerated claims for their efficacy but, having said that, it is likely that they do have some effect. The clinician should be aware that the ingredients are often not actually what is stated on the label and that many are not actually available to the horse in the form in which they are supplied. 3. Management. Under this heading should be included foot balancing and farriery, very valuable adjuncts to treatment that are described in Section 10.1. The main management tool, however, is rest. The ultimate is when the animal is cross-tied and in slings. However, so-called ‘box rest’, when an animal is confined to a stall or very small outside area, is very useful. It is very important in many conditions when higher doses of NSAIDs are being given that the animal is confined so that it cannot overuse the damaged joint. Many damaged joints, tendons and ligaments will heal if they can be rested. This is very difficult to achieve with certain horses that do not settle well when confined, but there are some tricks available to help the clinician: (i) having another quiet horse confined in the next box; (ii) having a mirror in the stable; or (iii) using various devices that oblige the horse to take a considerable time in obtaining its food. Advice should always be given with care. It is obviously counter-productive to have a horse that constantly ‘box-walks’ confined to a box; it would be better to have such a horse confined to a very small paddock. It is very important that management does not bring on some other condition, e.g. having the horse confined on manure, and it then developing ‘thrush’, or not allowing a horse to move that then develops laminitis. All management tools should be discussed with the owner and, if the clinician is in any doubt, a follow-up visit should be arranged. 5. Sodium hyaluronate. An i/v injectable, this is even more expensive, so the cost–benefit balance needs to be considered with care. 6. Tiludronic acid. This treatment is even more expensive than the foregoing, as not only is the medicine expensive but it also has to be given as a drip under veterinary supervision. The main claims for success involve spavin (see Section 11.5) and navicular damage (see Section 11.8). However, any joint condition requiring bone remodelling should benefit. It is not sensible here to make a long list of all possible lameness problems in the donkey, as many conditions will be covered in the sections below on the horse (Sections 11.4 and 11.5). However, it should always be remembered that the donkey is an extremely stoical beast. Fractures should always be considered with even moderate lameness; obviously, any swelling will direct the clinician to the source of lameness. However, in the absence of clues it is important to work up the leg methodically once foot lameness has been eliminated. Radial paralysis may mislead the clinician: the donkey initially appears fracture lame, but careful observation will reveal that the animal is able to bear weight when the leg is placed in the correct position. Normally there is a lack of skin sensation on the dorsal aspect of the pastern. Prognosis in these cases is good, as the animal rapidly learns to flick the foot forward when walking. Normally the animal will appear sound in 3 months, but full sensation may not return for over 12 months. Osteoarthritis causing lameness is common in the elderly donkey, the carpus being the most commonly affected joint. Joint effusion is marked. A joint block (see Section 11.8) can be performed to confirm the diagnosis, but with experience this may be unnecessary. Draining the fluid and injecting intra-articular steroid may be all that is required. This procedure gives considerable relief to the donkey, and will often remain so for more than 18 months. Naturally, it can be repeated, but the effective relief is much shorter following second and subsequent injections. Upward fixation of the patella is not uncommon in the young, poorly developed donkey, and so the need for median ligament desmotomy is rare. Most of these cases will cure with time provided that nutrition and exercise are improved. A short course of phenylbutazone is worthwhile. A much less common condition, which may confuse the practitioner, is rupture of the peroneus tertius muscle, part of the reciprocal apparatus. In this condition the stifle will flex but the hock remains in extension. This condition may be seen in the old, debilitated donkey, but it has also been reported to occur in the overworked animal. The prognosis is not good in the older animal, but normal function will return within 2–3 months if the debilitated donkey is rested and fed well. The third condition in this group is when the Achilles tendon slips off the point of the hock. This condition will alarm the donkey, which will try to move and then may even bolt, as the leg feels strange. However, I do not think this condition is actually acutely painful. The prognosis is good and normal function returns within 2 months. Sweeny is atrophy of any group of muscles. However, when considering the horse it is normally associated with atrophy of the supraspinatus and infraspinatus muscles of the shoulder. This is seen as complete wasting of these muscles, revealing the spine of the scapula. The cause is trauma to the suprascapular nerve by a blow to the point of the shoulder, which may be from a kick, hitting a gatepost or striking the shafts of a cart. Nevertheless, rarely is the cause of the trauma discovered as muscle atrophy takes time to occur. There is no treatment. Rarely do the muscles regenerate. However, the horse is seldom lame and can be used as normal. Again, this is caused by trauma to the cranial aspect of the shoulder, and lameness is marked. There will be pain in the area of the shoulder, particularly when the joint is flexed. A standard flexion test will make the degree of lameness worse. Treatment is usually by parenteral NSAIDs, or even topically. Normally, box rest is not required provided the horse is not allowed violent exercise. The horse should become sound within 12 weeks. A rare condition, it is associated with either: (i) violent movement of the joint, causing a small fracture of the tuber scapulae; or (ii) a kick, causing a small fracture of the lateral tuberosity of the humerus. There is no instability of the joint, but the horse will become progressively more lame, particularly after flexion. There is rarely any swelling – or indeed pain – associated with the area. A definitive diagnosis could be made with a shoulder joint nerve block (see Section 11.8). Radiography may be helpful, but often the fracture is hard to visualize. Joint medication with a long-acting steroid is helpful, and may be effective for 12 months. However, repeated medication will not last nearly as long, and NSAIDs will be palliative only initially. The long-term prognosis is poor. This fracture will present a confusing picture. The horse is going to be very lame, with sudden onset. With a severe fracture of the neck of the scapula there will be crepitus and abnormal movement, and so the diagnosis will be straightforward; prompt euthanasia is the only course of action. However, there may be less obvious fractures that, if they do not involve the shoulder joint, will eventually fuse and the horse will become sound; this process may take 9–12 months. There is no need to box-rest the horse provided no violent exercise is permitted. The horse will appear fracture lame. Indeed, there may be a fracture of the humerus, which is often the cause of radial paralysis as the nerve runs around the humerus in the musculospiral groove. In this case there will be crepitus and abnormal movement of the upper leg. Immediate euthanasia is indicated. However, it is vital that clinicians recognize when the radial nerve is paralysed without fracture of the humerus. The prognosis without a fracture is good. The radial nerve may be crushed or badly damaged by a fall on concrete or by having the leg crushed high up. Radial paralysis can also be caused by long recumbency on a hard surface, and this should be avoided at all costs during a long surgical operation. As the radial nerve supplies all the extensor muscles of the fore limb, radial paralysis means that the horse cannot extend either its knee or fetlock, so it will drag the hoof along the ground. However, if the foot is placed on the ground the horse can bear weight without any problem. Remarkably quickly, the horse will learn to flick its foot forward, so that the problem will only be obvious to an astute observer. Obviously, the clinician hopes that the radial paralysis is only temporary but, even if the radial nerve is permanently damaged, the horse can still be worked as there is no pain involved. Normally a self-inflicted problem, this is a bursitis on the point of the olecranon caused by repeated trauma from the hind shoe as the horse gets up. It rarely occurs in horses outside, but usually in the stabled horse. The hind shoes should be removed and the toes of the hind hooves shortened. A soft floor, ideally rubber matting, should be provided, or the horse should be turned out. Injecting corticosteroids into the bursa should be avoided on account of the danger of sepsis. The prognosis is good, except there is always likely to be some scarring. If the elbow develops an open wound then the prognosis is very guarded; topical NSAIDs may speed recovery if the wound heals. Normally disastrous, this may be either compound, severely commuted or involving a joint. Nevertheless, in extremely rare cases healing can be accomplished with a massive nursing input. For surgical repair a general anaesthetic is required. Four holes are drilled into the toe of the hoof, then two wire loops threaded through these holes and attached to a rope. Traction must then be applied with the horse anchored by another rope around the axilla. When the surgeon is satisfied that the ends of the fracture are in apposition, a cast covering the whole leg, including the foot, is applied as far towards the axilla as possible. The horse is given an assisted recovery and kept in slings. The cast will need to be removed and replaced in 3 weeks; in a further 3 weeks the cast can be removed and the leg splinted in a full Robert Jones, with a lateral wooden extension. The horse needs to be kept in slings for a total of 12 weeks. Hopefully, by then union will have been accomplished. Clinicians should remember that most conditions associated with the carpus are associated with swelling, and so diagnosis of the joint involved is straightforward. However, a specific diagnosis will often not be so easy. Problems with the carpus are commonly seen in the foal soon after birth. There may be lateral or medial deviation, which must be differentiated from: (i) valgus, a deviation of the third metacarpal bone laterally; and (ii) varus, the less common medial deviation. These latter two conditions can be corrected surgically by reducing the growth of one side of the meta-carpal bone. Surgery involves either the use of staples or stripping the periosteum. This must be carried out before 6 months of age, ideally at 3–4 months so that there is still ample growth left in the metacarpal bone. The problem of deviation affecting the carpus cannot be corrected; if it is severe euthanasia is indicated. Casting the leg is recommended by some authorities, but this is extremely hazardous on account of the danger of pressure sores. Conservative treatment should be tried; the mare and foal should be kept on a small paddock and glue-on lateral or medial extension shoes applied. There also may be seen a condition of the carpus involving anterior deviation, sometimes called ‘bucked knees’. When standing, the horse will have one or both knees slightly flexed; if this is seen in a foal the condition will resolve in most cases without treatment. However, if it is severe, casting for a maximum of 10 days should be tried. Normally, the legs will then straighten after the cast is removed and the flexor tendons relax. Historically, the foal with this condition was treated with large doses of oxytetracycline: it was believed that the antibiotic reduced the uptake of calcium, but this is now known to be false. This condition can also occur in the adult following injury, resulting in overcompensation of the flexor apparatus; it is very unlikely to respond to casting or any other treatment. Another problem seen in the foal affects not only the carpus but the entirety of both forelegs – they are both bowed in the same direction, the ‘windswept foal’. The cause is thought to be when there is too little space in the mare’s abdomen for the developing foal in the uterus. Normally this condition, provided the foal can feed, will correct itself. Clinicians will commonly see, in the adult horse, a swelling on the anterior aspect of the carpus; this is called a hygroma and is a bursitis cranial to the carpal joint. It is normally caused by trauma. The horse is rarely lame, and the swelling should be left alone. If the horse is lame and the lameness is made worse by carpal flexion, treatment should be tried. First, the joint is surgically prepared; under sterile conditions the practitioner should draw off as much of the fluid as possible. The joint should be injected with a long-acting corticosteroid; a full Robert Jones splint is then applied for 10 days. The condition is likely to recur in 1–2 years, although the treatment can be repeated. The horses can develop a true carpitis, which is osteoarthritis of the carpal joint and normally follows trauma. It will be seen as lameness, but this should diminish unless there is a fracture of one of the carpal bones. However, even without a fracture new bone is likely to be laid down and will cause permanent lameness in the long term. Initial treatment with NSAIDs will be helpful, and permanent glucosamine treatment may be tried.
11.1 Treating the Lame Horse
History
Examination
Preliminary diagnosis
Simple treatment options available to the clinician
11.2 Fore Limb Lameness in the Donkey not Associated with the Foot
11.3 Hind Limb Lameness in the Donkey not Associated with the Foot
11.4 Fore Limb Lameness in the Horse not Associated with the Foot
Sweeny
Inflammation of the bicipital bursa
Arthritis of the shoulder joint
Fracture of the scapula
Paralysis of the radial nerve on its own or associated with a fracture of the humerus
Capped elbow
Fracture of the radius
Problems associated with the carpus
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
