Cirurgia em Animais de Companhia: Complicações pós-cirúrgicas na resolução de luxações patelares em cães de pequeno porte
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2020-07-23
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A luxação patelar é uma das patologias ortopédicas mais frequentemente diagnosticadas em cães, sendo uma das principais causas de claudicação e dificuldades locomotoras em animais, especialmente em raças de pequeno porte. A articulação do joelho é uma das articulações mais complexas do organismo, sendo composta por diversas estruturas ósseas, fibrocartilagíneas e diversos tecidos musculares. O correto desenvolvimento e alinhamento de todas estas estruturas é essencial ao desenvolvimento de uma articulação estável e funcional. O principal grupo muscular que atua sobre a patela é composto pelos músculos vasto lateral, medial e intermédio e designa-se por quadricípite femoral. Este grupo é responsável pela extensão da articulação e a sua ação, juntamente com as restantes estruturas do mecanismo extensor do joelho, é preponderante na predisposição de luxações. Os animais de pequeno porte apresentam uma maior predisposição ao desenvolvimento desta patologia, sobretudo quando nos referimos a luxações patelares mediais. São diversos os fatores que constituem um risco para o desenvolvimento de luxações patelares tais como o género, idade, peso e raça. O diagnóstico de luxação patelar é realizado através do exame físico do animal, do seu historial e dos sinais clínicos que este apresenta. Os exames imagiológicos, apesar de não serem fundamentais para o diagnóstico da patologia, permitem uma melhor avaliação e compreensão da extensão das lesões, facilitando desta forma o planeamento da terapia a realizar. O tratamento cirúrgico das luxações patelares envolve a utilização isolada ou combinada de técnicas de reconstrução dos tecidos moles, adjacentes à articulação, e dos tecidos ósseos do fémur distal e tíbia proximal. As taxas de complicações pós-cirúrgicas são relativamente baixas sendo que na maioria dos casos os animais adquirem uma funcionalidade normal do membro. As complicações mais comuns são a recidiva da luxação e falha dos implantes de osteossíntese. Resultados: Estes dados foram obtidos através da análise retrospetiva dos relatórios clínicos disponibilizados pelo CHV Fregis, referentes ao período decorrido entre janeiro de 2008 e maio de 2019. Cento e sessenta e dois casos de luxações patelares foram analisados, com um total de 286 articulações afetadas com a seguinte distribuição por raça: Yorkshire terrier (69); Chihuahua (33); Bulldog francês (23); Sptiz alemão (16), Bichon Frise (12); Boston terrier (7) e Shih Tzu (2). O rácio macho/fêmeas foi de 1/1,3, com os animais a apresentarem uma média de idade de 5 anos. Cerca de 77% dos animais estavam afetados bilateralmente. A distribuição das luxações patelares (284 LPM; 2 LPL) foi a seguinte: Grau I (n=37), Grau II (n=130), Grau III (n=95), Grau IV (n=24). A taxa de complicações pós-cirúrgicas foi de 38%, com 35 dos 91 animais operados a evidenciarem algum tipo de complicação, traduzindo-se numa taxa de complicação por articulação cirurgicamente intervencionada de 35%. Oitenta e cinco por cento destas complicações foram classificadas como significativamente graves, com necessidade de revisão cirúrgica ou com perda da funcionalidade do membro. Verificou-se uma maior incidência de complicações nas articulações que apresentavam luxações de grau III e IV, que corresponderam a 72% das ocorrências observadas. A incidência de complicações, dentro do seu respetivo grau, foi superior nas luxações de grau IV, comparativamente com as restantes, com 53% das articulações operadas a apresentarem complicações. A recidiva de luxação foi a complicação mais frequente, correspondendo a 43,4% das complicações, seguida pela falha dos implantes de osteossíntese e de reforço articular, que correspondeu a 20,5% das articulações afetadas. Um processo de doença articular degenerativa afetou cerca de 10,4% das articulações operadas e um caso apresentou um processo degenerativo crónico associado a uma artrite séptica crónica, correspondendo a um total de 13% das articulações que apresentaram complicações (n=5), e tiveram um prognóstico reservado com a necessidade de implementação de um tratamento conservativo adjuvante ou planeamento de uma revisão cirúrgica. A taxa de satisfação pós-cirúrgica, relativa ao número de articulações operadas e incluindo os casos que necessitaram de revisão cirúrgica, foi de 94%.
Patellar luxation is one of the most diagnosed orthopaedic pathologies in dogs and one of the main causes of hindlimb lameness in animals, especially in small dog breeds. The knee is one of the most complex articulation of the body and is composed by several different bone, fibrocartilage and soft tissue structures. The correct development and alignment of all these structures is essential for the achievement of a structurally stable and functional articulation. The main muscular group that exerts its functions over the patella is the femoral quadriceps which is composed by the association of the lateral, medial and intermedius vastus muscles. This muscular group is mainly responsible for the extension of the knee, along with several other structures, and its malalignment is crucial to the development of patellar luxation. Small animals tend to present a greater risk of developing patellar luxation, especially in cases of medial luxation. There are several other risk factors that can cause this pathology that include gender, age, weight and breed. The diagnosis of patellar luxation is performed during the animal physical evaluation and in association with the medical history and symptoms. The imagiological exams, despite not being fundamental for the diagnosis, allow for a better understanding and evaluation of the severity and extension of the lesions and, therefore, a better therapeutic planning. The surgical treatment of patellar luxation is composed of individual or combined usage of soft tissues, that are part of or surround the articulation, and distal femur and proximal tibial restructuring. The post-surgical complication rates are generally low and in the great majority of cases a full range mobility of the affected limb is achieved. The most common complications include reluxation and osteosynthesis implant failure. Results: The data was compiled throw a retrospective study of case reports made available by CHV Fregis, between January 2008 and May 2019. One hundred and sixty-two cases of patellar luxation were analyzed, with a total of 286 joints affected with the following presentation by race: Yorkshire terrier (69); Chihuahua (33); French Bulldog (23); German Sptiz (16), Bichon (12); Boston terrier (7) and Shih Tzu (2). The male to female ratio was 1/1.3, with an average age of 5 years. About 77% of the animals were affected bilaterally. The distribution of patellar luxation (284 MPL; 2 LPL) was as follows: Grade I (n = 37), Grade II (n = 130), Grade III (n = 95), Grade IV (n = 24). The rate of post-surgical complications was 38%, with 35 of the 91 surgically intervened animals showing some type of complication, resulting in a complication rate for surgically intervened joints of 35%. Eighty-five percent of these complications were classified as significantly severe with the loss of limb function or requiring surgical revision. There was a higher incidence of complications in the joints that presented a grade III and IV luxation, which corresponded to 72% of the observed occurrences. The incidence of complications, within their respective degree, was higher in grade IV luxation when compared to the others, with 53% of the intervened joints developing complications. Reluxation was the most frequent complication, corresponding to 43.4% of the occurrences, followed by failure of osteosynthesis and joint reinforcement implants, which corresponded to 20.5% of the affected joints. A degenerative joint disease process affected 10.4% of the intervened joints and one case had a chronic degenerative process associated with chronic septic arthritis. In total, 13% of the joints that presented complications were of degenerative origin (n = 5) and had a poor prognosis with the need to implement an adjunctive conservative treatment or surgical review. The rate of post-surgical satisfaction, relative to the number of intervened joints, was 94%.
Patellar luxation is one of the most diagnosed orthopaedic pathologies in dogs and one of the main causes of hindlimb lameness in animals, especially in small dog breeds. The knee is one of the most complex articulation of the body and is composed by several different bone, fibrocartilage and soft tissue structures. The correct development and alignment of all these structures is essential for the achievement of a structurally stable and functional articulation. The main muscular group that exerts its functions over the patella is the femoral quadriceps which is composed by the association of the lateral, medial and intermedius vastus muscles. This muscular group is mainly responsible for the extension of the knee, along with several other structures, and its malalignment is crucial to the development of patellar luxation. Small animals tend to present a greater risk of developing patellar luxation, especially in cases of medial luxation. There are several other risk factors that can cause this pathology that include gender, age, weight and breed. The diagnosis of patellar luxation is performed during the animal physical evaluation and in association with the medical history and symptoms. The imagiological exams, despite not being fundamental for the diagnosis, allow for a better understanding and evaluation of the severity and extension of the lesions and, therefore, a better therapeutic planning. The surgical treatment of patellar luxation is composed of individual or combined usage of soft tissues, that are part of or surround the articulation, and distal femur and proximal tibial restructuring. The post-surgical complication rates are generally low and in the great majority of cases a full range mobility of the affected limb is achieved. The most common complications include reluxation and osteosynthesis implant failure. Results: The data was compiled throw a retrospective study of case reports made available by CHV Fregis, between January 2008 and May 2019. One hundred and sixty-two cases of patellar luxation were analyzed, with a total of 286 joints affected with the following presentation by race: Yorkshire terrier (69); Chihuahua (33); French Bulldog (23); German Sptiz (16), Bichon (12); Boston terrier (7) and Shih Tzu (2). The male to female ratio was 1/1.3, with an average age of 5 years. About 77% of the animals were affected bilaterally. The distribution of patellar luxation (284 MPL; 2 LPL) was as follows: Grade I (n = 37), Grade II (n = 130), Grade III (n = 95), Grade IV (n = 24). The rate of post-surgical complications was 38%, with 35 of the 91 surgically intervened animals showing some type of complication, resulting in a complication rate for surgically intervened joints of 35%. Eighty-five percent of these complications were classified as significantly severe with the loss of limb function or requiring surgical revision. There was a higher incidence of complications in the joints that presented a grade III and IV luxation, which corresponded to 72% of the observed occurrences. The incidence of complications, within their respective degree, was higher in grade IV luxation when compared to the others, with 53% of the intervened joints developing complications. Reluxation was the most frequent complication, corresponding to 43.4% of the occurrences, followed by failure of osteosynthesis and joint reinforcement implants, which corresponded to 20.5% of the affected joints. A degenerative joint disease process affected 10.4% of the intervened joints and one case had a chronic degenerative process associated with chronic septic arthritis. In total, 13% of the joints that presented complications were of degenerative origin (n = 5) and had a poor prognosis with the need to implement an adjunctive conservative treatment or surgical review. The rate of post-surgical satisfaction, relative to the number of intervened joints, was 94%.
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Dissertação de Mestrado Integrado em Medicina Veterinária
Palavras-chave
cirurgia de pequenos animais , luxação patelar