Other Causes of Lameness
There are many other causes of lameness in dogs. Please consult with your veterinarian regarding the proper diagnostic tests and potential causes of your dog's lameness, as well as a detailed treatment plan.
Listed are some of the more common causes of lameness other than the ones previously discussed. This area will continue to grow and provide additional information.
Fractures may occur in any bone, and in any region of the bone, and may also include a joint. Trauma is the main cause, either associated with automobile trauma, jumping from a height, or involvement in a
dog fight. Your veterinarian will help you decide the best method of treatment, which often involves surgery. Surgical stabilization may involve pins and wires, intramedullary rods and screws, bone plates and screws, or external skeletal fixation with pins or wires and clamps and bars. A cast or splint may be used to repair certain types of fractures of bones below the elbow or stifle. Close attention to post-operative care instructions will be critical to minimize complications.
Unfortunately, bone cancer is an all too frequent cause of lameness in large to giant breed middle aged to older dogs, and in some cases, very young dogs. The most frequent sites are away from the elbow (upper humerus, lower radius) and toward the stifle (lower femur, upper tibia). Lameness progresses over time Initially, the lameness may be attributed to a sprain/strain or arthritis. But the lameness progressively gets worse and the area feels enlarged and painful. Radiographs are usually diagnostic, and a fine needle aspirate or biopsy can confirm the diagnosis. By the time of diagnosis, the vast majority of cases have already spread to the chest, even if tumors are not yet visible on chest radiographs. Survival time without treatment is 2-5 months. Treatment usually involves amputation (some cases may be managed with limb sparing
techniques, but case selection is very important) and chemotherapy. Average survival time with treatment alone is approximately 1 year. Oddly, amputation alone does not appear to significantly increase survival time but eliminates the source of pain. Owners may be reluctant to amputate, but consider that fact that the patient is only using 3 legs already in most cases, and the dog is in severe pain.
Other tumors may affect joints and muscles. Fortunately this are less common. Some tumors of the joints can be very aggressive, while others may be controlled with amputation for a relatively long period of time.
Osteochondrosis (OC) / Osteochondritis Dissecans (OCD)
This condition occurs when cartilage does not transition to bone as part of the normal growth and development of bones and joints. The primary location is on the head of the humerus (the ball part of the shoulder joint). It causes mild to severe forelimb lameness in dogs that are 6 to 12 months of age. Both shoulder joints are often affected, but one is usually more lame and painful than the other. A key diagnostic test is pain with extension of the shoulder joint in a young dog. Confirmation of the diagnosis is a radiograph with a characteristic lesion seen. Surgical removal of the cartilage flap generally results in significant improvement.
The biceps muscle crosses both the shoulder and elbow joints. Sometimes it becomes inflamed, stretched, and in advanced cases, partially or completely torn. Middle aged to older active dogs are most frequently affected. Lameness may be intermittently mild to severe, continuous non weight-bearing lameness. The test that is usually performed is to simultaneously flex the shoulder and extend the elbow to put maximum tension on the muscle-tendon unit; this results in pain. Palpation directly over the upper part of the biceps tendon also creates pain. A diagnostic test to more completely characterize the condition is ultrasound of the tendon and muscle. Treatment options include conservative management with rest and nonsteroidal anti-inflammatory medications, extracorporeal shockwave treatment, therapeutic laser, therapeutic ultrasound, biologic therapy with stem cells or platelet rich plasma, and surgery.
This muscle runs along the front of the scapula and inserts on the upper part of the humerus (greater tubercle). The tendon insertion of this muscle may become inflamed, stretched, or torn. Chronic cases often have some calcification of the tendon insertion. Diagnostic ultrasound can more completely characterize the problem. Dogs generally have a mild to moderate forelimb lameness that progressively worsens if not treated. Pain may also be present when the area is palpated. Treatment options include conservative management with rest and nonsteroidal anti-inflammatory medications, extracorporeal shockwave treatment, therapeutic laser, therapeutic ultrasound, biologic therapy with stem cells or platelet rich plasma, and surgery.
This muscle runs along the back of the scapula and inserts on the upper part of the humerus below the supraspinatus muscle. The tendon/muscle may become damaged with fibrosis. Initially, owners may remember some degree of lameness, but as the muscle and tendon undergo fibrosis, the front limb assumes the characteristic position with the elbow rotated in to the chest, and the foot and forelimb externally rotated. Diagnostic ultrasound can more completely characterize the problem. Dogs generally have a mild to moderate forelimb lameness with inability to completely extend the shoulder joint. Treatment is generally very effective, and consists of completely releasing the scar tissue with rehabilitation after surgery to help prevent recurrence.
Medial Shoulder Instability (MSI)
Dogs are engaging in more sporting events that result in much torsion of the shoulder joint while turning sharply or turning while landing after a jump. The medial glenohumeral ligament (medial collateral ligament) and/or subscapularis muscle may be stretched or torn. Lameness varies from mild intermittent to continuous severe lameness. A physical exam test that is frequently performed is to fully extend, and then abduct (pull the lower limb away from the body); dogs with MSI will have increased abduction and pain at the end of abduction. Magnetic resonance imaging may be useful in identifying damaged tissues, but it often underestimates the degree of damage. Diagnostic arthroscopy is currently the gold standard in identifying the problem. Although some claim that diagnostic ultrasound may be useful in diagnosing the condition, board-certified radiologists have stated that is is not possible to properly examine the area with ultrasound because too many artifacts are present while trying to image the area. Conservative treatment consists of rest and hobbles to prevent abduction while the damaged tissues heal. Extracorporeal shockwave treatment may help to speed the healing process. Conservative management is generally effective in improving the lameness if the degree of damage is relatively mild. Careful rehabilitation is important to strengthen the area, but alterations in activity may be necessary because dogs will be prone to re-injury. Surgical reconstruction of the tissues may be necessary if the injury is severe or recurrent. Older methods, such as thermal or capsular shrinkage have fallen out of favor, and may actually further damage tissues.
Other than fractures or other trauma, common causes of lameness in the carpus include carpal hyperextension injury and flexural carpal deformity. Carpal hyperextension injury occurs with jumping down from a distance and damaging the palmar fibrocartilage and intercarpal ligaments. This is not damage to the flexor tendons. Mild injuries may be managed with prolonged splinting, but generally surgery is the treatment of choice, especially in larger dogs with significant hyperextension. Surgery involves surgical fusion of the affected joints by removing the articular cartilage, packing the area with bone graft, and stabilizing the area with a bone plate and screws. The area is usually protected with a cast or splint until there is some bony healing. If possible, a partial arthrodesis may be performed of the lower joints, with preservation of the main motion joint. However, if that joint is also involved, a complete fusion must be performed which eliminates any motion of the carpus. Dogs usually adapt quite well, however.
Carpal flexural deformity is a condition seen in young dogs. The flexor carpi ulnaris muscle appears to be very tight, resulting in the carpus being in a flexed position during weight bearing, with some rotation of the foot. Generally change to a large breed growth diet and time result in correction, but occasionally surgery is necessary.
Dislocation of the hip joint may occur with trauma. In cases where minimal trauma causes luxation, such as bumping into furniture, careful evaluation for hip dysplasia must be made. If the hip is not dysplastic, closed reduction followed by sling immobilization may be successful. Otherwise, surgical stabilization or a femoral head and neck excision should be performed.
Major trauma may result in a deranged stifle. Repair of this injury requires a thorough assessment of all injured structures and considerable experience to surgically correct the injuries.
Osteochondritis dissecans (OCD) may affect the medial aspect of the lateral femoral condyle. Advances in surgical techniques can result in good function, but arthritis will be present.
Several traumatic injuries may occur in the tarsus, including fractures or dislocations of various bones of the hock. In addition, injury or degeneration of the common calcaneal tendon may occur, resulting in a "dropped hock" appearance. Splinting or casting may be effective in mild injuries, but more severe injuries require surgery. The post-operative treatment is extremely important to prevent re-injury.