TTTT℗: Uma nova abordagem à compreensão e tratamento cirúrgico das luxações da patela
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2018-10-24
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A luxação patelar (LP) é um problema ortopédico muito comum em cães, sendo o mais frequente dentro dos que envolvem a articulação do joelho canino. Surge, na maioria dos casos, consequentemente a deformidades anatómicas congénitas, conformacionais e biomecânicas, que se agravam durante o crescimento do animal e desalinham o mecanismo extensor do grupo muscular quadríceps femoral. O tratamento cirúrgico, principalmente em animais jovens e em animais sintomáticos, é fortemente aconselhado o mais brevemente possível. O principal objetivo do tratamento é o realinhamento do mecanismo extensor, sendo para isso importante a compreensão das deformidades anatómicas presentes em cada caso. São diversas as técnicas cirúrgicas utilizadas, sendo geralmente usada uma combinação de várias, com objetivo de realinhamento e de estabilização da patela no sulco troclear. A transposição da tuberosidade tibial (TTT) é um método bastante utilizado, surgindo descrita na literatura com taxas de complicações maiores (CM) entre os 13 e 18,5%. Com o objetivo de reduzir essas taxas de complicações e tornar o procedimento mais metódico e objetivo, Massimo Petazzoni desenvolveu, em 2014, uma nova técnica e dispositivo de transposição da tuberosidade tibial - TTTT℗ (Tibial Tuberosity Transposition Tool). Este dispositivo promove uma translação lenta e gradual da crista tibial parcialmente osteotomizada e estabiliza temporariamente a crista na sua nova posição. Na fixação definitiva não há perfuração da tuberosidade tibial e é apenas utilizado um implante como espaçador. Esta dissertação de mestrado apresenta esta nova técnica e os resultados de um estudo retrospetivo de 116 casos. Tem como objetivos: determinar a taxa de complicações maiores em cães; perceber quais foram essas complicações e a sua causa; comparar os resultados com a técnica clássica; e determinar se a TTTT℗ é segura em animais em crescimento e bilateralmente exequível no mesmo procedimento, bem como as taxas de CM nesses casos. Foram operados 116 joelhos de 84 cães com LP medial, entre março de 2015 e maio de 2018: 34 com LPM grau I, 70 com grau II, 8 com grau III e 4 com grau IV. Sempre que considerado necessário, foram associadas outras técnicas como trocleoplastias, imbricações e osteotomias femorais corretivas. Como CM foi considerado qualquer problema que necessitasse de segunda intervenção cirúrgica. Surgiram 7 em 116 joelhos operados (6,03%): 4 recidivas de luxação, 2 migrações do implante e 1 fratura de tíbia. Todas as CM relatadas surgiram por erros técnicos do cirurgião ou por decisões cirúrgicas mais conservadoras. Nenhum dos 6 cães em crescimento sofreu CM (0%), bem como nenhum dos 14 cães cuja LP bilateral foi resolvida simultaneamente no mesmo procedimento cirúrgico (0%). Com base nos resultados preliminares deste estudo retrospetivo de 116 casos, a técnica TTTT℗ é um procedimento seguro, com resultados consistentes e promissores. Apresenta taxas de complicações maiores inferiores à técnica clássica de TTT e é exequível em animais em crescimento, e num único procedimento cirúrgico em casos bilaterais. Os resultados obtidos são limitados por ser um estudo retrospetivo. Devem ser realizados mais estudos, com maior número de animais, para obtenção de resultados mais significativos.
Patellar luxation is one of the most common orthopaedic conditions in dogs and the most common disease affecting the canine stifle. It is primarily a congenital and developmental condition that results in a misalignment of the extensor mechanism of the stifle. The surgical treatment is recommended as soon as possible, mostly in younger and symptomatic patients. As it aims to restore the normal alignment of the extensor mechanism, it is essential to understand the bone deformities presented in each individual case. Multiple surgical techniques to treat patellar luxation have been described and usually a combined surgical treatment is needed to realign and provide stabilization of the femoropatellar joint. Tibial tuberosity transposition (TTT) is one of the mostly used surgical techniques and its major complications occur in 13-18,5% of cases. A new special tool - TTTT℗ (Tibial Tuberosity Transposition Tool) - and technique were designed in 2014 by Massimo Petazzoni to reduce those major complication rates and to make a more methodical and objective procedure. This tool allows a slow bone bending of the tibial tuberosity after partial tibial tubercle osteotomy and stabilizes the shifted portion in position until final bone fixation. The proximal part of the tibial tuberosity is stabilized by inserting a pin as a spacer, without tuberosity pinning or distal cerclage wiring. This master’s dissertation presents the TTTT℗ technique and retrospectively evaluates 116 cases. The purposes of this study are: to report the major complication (MC) rates and the risk factors for those complications; compare those rates to the ones of the classic TTT; ascertain if this technique is safe in growing animals (active growth plates) and single-session bilaterally doable; and the major complication rates in those particular cases. 116 MPL of 84 dogs were operated between March 2015 and May 2018: 34 with MPL grade I, 70 with grade II, 8 with grade III and 4 with grade IV. Whenever considered necessary, other techniques such as wedge recession sulcoplasty, lateral imbrications and corrective femoral osteotomies were associated. Any problem that required a second surgical intervention was considered as a major complication. There were 7 out of the 116 cases (6.03%): patellar 4 luxation recurrences, 2 implant migrations and 1 tibial fracture. All 7 were due to technical errors of the surgeon or to more conservative surgical decisions. None of the 6 growing dogs suffered MC (0%) as well as none of the 14 dogs whose bilateral patellar luxation was resolved simultaneously in the same surgical procedure (0%). Based on the preliminary results of this retrospective study of 116 cases, TTTT℗ technique is a safe procedure with consistent and promising results. It presents lower rates of major complications than the classic TTT technique. It is safe and doable in growing animals, and in a single surgical procedure in bilateral cases. As it is a retrospective study, these results are limited by the information provided. More studies, with higher number of animals, should be performed to obtain more significant results.
Patellar luxation is one of the most common orthopaedic conditions in dogs and the most common disease affecting the canine stifle. It is primarily a congenital and developmental condition that results in a misalignment of the extensor mechanism of the stifle. The surgical treatment is recommended as soon as possible, mostly in younger and symptomatic patients. As it aims to restore the normal alignment of the extensor mechanism, it is essential to understand the bone deformities presented in each individual case. Multiple surgical techniques to treat patellar luxation have been described and usually a combined surgical treatment is needed to realign and provide stabilization of the femoropatellar joint. Tibial tuberosity transposition (TTT) is one of the mostly used surgical techniques and its major complications occur in 13-18,5% of cases. A new special tool - TTTT℗ (Tibial Tuberosity Transposition Tool) - and technique were designed in 2014 by Massimo Petazzoni to reduce those major complication rates and to make a more methodical and objective procedure. This tool allows a slow bone bending of the tibial tuberosity after partial tibial tubercle osteotomy and stabilizes the shifted portion in position until final bone fixation. The proximal part of the tibial tuberosity is stabilized by inserting a pin as a spacer, without tuberosity pinning or distal cerclage wiring. This master’s dissertation presents the TTTT℗ technique and retrospectively evaluates 116 cases. The purposes of this study are: to report the major complication (MC) rates and the risk factors for those complications; compare those rates to the ones of the classic TTT; ascertain if this technique is safe in growing animals (active growth plates) and single-session bilaterally doable; and the major complication rates in those particular cases. 116 MPL of 84 dogs were operated between March 2015 and May 2018: 34 with MPL grade I, 70 with grade II, 8 with grade III and 4 with grade IV. Whenever considered necessary, other techniques such as wedge recession sulcoplasty, lateral imbrications and corrective femoral osteotomies were associated. Any problem that required a second surgical intervention was considered as a major complication. There were 7 out of the 116 cases (6.03%): patellar 4 luxation recurrences, 2 implant migrations and 1 tibial fracture. All 7 were due to technical errors of the surgeon or to more conservative surgical decisions. None of the 6 growing dogs suffered MC (0%) as well as none of the 14 dogs whose bilateral patellar luxation was resolved simultaneously in the same surgical procedure (0%). Based on the preliminary results of this retrospective study of 116 cases, TTTT℗ technique is a safe procedure with consistent and promising results. It presents lower rates of major complications than the classic TTT technique. It is safe and doable in growing animals, and in a single surgical procedure in bilateral cases. As it is a retrospective study, these results are limited by the information provided. More studies, with higher number of animals, should be performed to obtain more significant results.
Descrição
Dissertação de Mestrado em Medicina Veterinária
Palavras-chave
articulação do joelho , luxação patelar , transposição da tuberosidade tibial , TTTT℗ (Tibial Tuberosity Transposition Tool)