There are several possible ways of classifying the musculoskeletal diseases and the accuracy of any classification depends on the available information. The classification used here (Table 8.1) is simple and probably most relevant to the clinician.
Bone fractures are not uncommon in cats. The exact traumatic episode is generally unknown; cats either arrive home or are found in an injured state. Road traffic accidents or falls from a height are the most likely cause. Various surveys have been reported and indicate that the femur, tibia, mandible and pelvis are the most commonly fractured bones (Carter, 1964; Hill, 1977; Knecht, 1978). In a survey of feline pelvic fractures (Bennett, 1975) the average age of cats sustaining pelvic injury was 1.3 years; it is suggested that young animals learn to cope with their environmental hazards through experience, but the very young cat is more likely to remain close to the home environment and is thus more protected.
The repair of fractures is beyond the scope of this chapter. Various surgical techniques can be used, although conservative treatment is often gratifying as,
Table 8.1 Classification of diseases of the feline musculoskeletal system
Luxations/subluxations Tendon injuries
Metabolic bone diseases
Nutritional secondary hyperparathyroidism Osteodystrophy of mature cats Rickets (osteomalacia) Hypervitaminosis A Hypovitaminosis A
Renal secondary hyperparathyroidism Primary hyperparathyroidism Primary hypoparathyroidism
Traumatic arthritis Osteoarthritis
Infective arthritis Immune-based arthritis
Osteocartilaginous exostoses Osteosarcoma Extraskeletal osteosarcoma Extraskeletal osteoma Parosteal osteoma Chondrosarcoma Osteoma Osteoid osteoma Multilobular chondromas Osteoclastoma Giant cell sarcoma Spindle cell sarcoma Fibrosarcoma Synovioma Synovial sarcoma Aneurysmal bone cyst Fibrous dysplasia
Table 8.1 (continued)
Neoplastic and neoplastic-like lesions (continued)
Metastatic neoplasms of bones and joints Direct extension of neoplasms to bone Synovial cyst
Inherited, congenital and developmental disorders
Sacrocaudal dysgenesis in Manx Cats
Amelia and hemimelia
Arrested development of long bones of forelimbs
Mandible ramus aplasia
Craniofacial malformation in Burmese cats
Other skeletal abnormalities
Other congenital abnormalities
Other lysosomal storage diseases
Proximal femoral metaphyseal osteopathy Feline capital physeal dysplasia syndrome Hip dysplasia Osteochondrosis
Neuromuscular diseases Inherited myopathies
Feline X-linked muscular dystrophy Nemaline myopathy Generalised ossifying myositis Myotonia
Hereditary myopathy of the Devon Rex Glycogen storage diseases for example, with pelvic fractures. Recent studies have shown that the external fixator is well tolerated by the cat and can be used to treat a number of fracture problems in this species (Langley-Hobbs et al, 1997). In general, cats are very co-operative orthopaedic patients and healing complications are relatively rare.
Traumatic luxations of joints usually follow a suspected road accident or fall from a height. The hip is the most commonly dislocated joint of the cat
Hypokalaemic polmyopathy Burmese sporadic myopathy Localised ossifying myositis
Neuromuscular junction disorders
Myasthenia gravis Organophosphate toxicity
Neuropathy associated with hyperchylomicronaemia Neuropathy associated with sphingomyelinase deficiency Distal axonopathy of Birman cats
Ischaemic polyneuropathy (aortic thromboembolism) Polyneuropathy associated with salinomycin Diabetic polyneuropathy Traumatic neuropathy Neoplasia
Contracture of the gastrocmenius muscle/tendon
Diseases of the vertebral column
Intervertebral disc protrusions Spondylosis deformans and ankylosing hyperostosis Bacterial discospondylitis Atlantoaxial subluxation
Hypertrophic pulmonary osteoarthropathy
Myelofibrosis/osteosclerosis synd rome Feline hyperaesthesia syndrome
(Figure 8.1) (Bennett, 1975). This is usually treated successfully by external reduction under general anaesthesia. Strapping of the leg is not advisable in cats, since they tend not to tolerate the sling at all well. Recurrent hip luxations may be treated by transarticular pinning (Bennett & Duff, 1980) or by femoral head excision, although cats can often manage well with a permanently luxated hip (Bennett, 1975).
Total luxation or subluxation of the femorotibial joint may occasionally be seen following road traffic injuries (Figure 8.2). Such luxations are associated with cruciate and collateral ligament rupture. Careful
reconstruction of the damaged ligaments is recommended in these cases, although stabilisation of the joint with cross-pins or a single transarticular pin has been described (Figure 8.3); the pins are removed after 3 weeks. Antebrachiocarpal luxation in the cat is occasionally encountered and is best treated by carpal arthrodesis using a 2.7/2.0 mm hybrid carpal arthrodesis plate (Li et al., 1999). The femoropatellar joint may also luxate secondary to trauma and usually responds to capsular tightening. The patella may also luxate in association with a dislocated hip joint. The tarsocrural joint is commonly luxated or subluxated, often associated with fractures of the medial and/or lateral malleoli of the hock (Figure 8.4). Treatment is by fixation of the fractured malleoli, usually by a tension band wiring technique or by reconstructing the collateral ligaments of the hock. Although most ligament tears in cats are associated with major trauma, there is a report suggesting that there may be a gradual failure of the cranial cruciate rupture akin to that seen in dogs (Janssens et al., 1991; Schrauwers & Appeldoorn, 1991). Furthermore, a tentative association between cruciate failure and cardiomyopathy in the cat has been suggested (Janssens et al., 1991). However, most cranial cruciate ligament failures in the cat are caused by major trauma and
Was this article helpful?
Thank you for deciding to learn more about the disorder, Osteoarthritis. Inside these pages, you will learn what it is, who is most at risk for developing it, what causes it, and some treatment plans to help those that do have it feel better. While there is no definitive “cure” for Osteoarthritis, there are ways in which individuals can improve their quality of life and change the discomfort level to one that can be tolerated on a daily basis.