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Flashcards in Artroplastia total do Joelho Deck (158):
1

Por que proteses condilares constrictas não podem ser utilizadas em pacientes com recurvatum?

Porque essas proteses não controlam a hiperextensão.

2

Quais são as indicações de uso de proteses tipo CCK? (Constricted condylar knee)

As proteses CCKs foram desenvolvidas para serem usadas em cirurgias de revisâo quando a instabilidade se faz presente e quando há dificuldade em artroplastias primarias quando há uma deformidade em valgo extrema e insuficiencia do ligamento colateral medial.

3

Quais são as vantagens em potencial das proteses com plataforma movel?

Menores forças estressantes de contato na superficie articular, movimento rotacional do polietileno tibial durante a marcha e auto-alinhamento do polietileno tibial compensando pequenos mal-alinhamentos rotacionais da base de sustentação tibial produzidos durante a implantação do sistema

4

Qual a indicação do uso de proteses unicompartimentais?

Muitos cirurgiôes defendem o uso de UKA em pacientes com artrose limitada a apenas um compartimento

5

Quais são as vantagens das UKA?

Poupa os ligamentos cruzados, reabilitação mais rapida que o as TKA, revisão para TKA mais facil.

6

Comente a estabilidade da protese rotatoria hinge

A protese hinge rotatoria é constricta nos planos sagital e coronal enquanto permite rotação livre no plano transverso para limitar a transferencia de forcas a interface osso-implante e permitir a substituição da estabilidade constricta de partes moles no plano coronal devido a insuficiencia dos suportes colaterais.

7

Quais são as indicações das proteses hinge?

As proteses hinge são indicadas em TKA primaria quando uma deformidade significante e perda do suporte de tecidos moles não permite que a estabilidade do joelho seja obtida ou quando um gap de flexão é criado a salta a constrição do implante condilar. Esse tipo de implante é usado em pacientes com insuficiencia ligamentar severa, gap de flexão e extensão, deformidade em recurvatum, doença neuromuscular, e procedimentos de salvação do membro.

8

Quais são os 2 tipos basicos de PTK primarios?

TKA que mantém o LCP e TKA que substitui o LCP

9

Como Dennis et al. descreveram o eixo de flexão do joelho?

O eixo de flexão do joelho varia em forma helicoidal no joelho normal, com média de translação posterior do condilo femoral medial sobre a tibia 2mm posterior durante a flexação, comparado com translação de 21mm do condilo lateral.

10

Quando o LCA é seccionado, como se comporta o eixo de flexão do joelho?

O eixo torna-se mais variavel, com uma media de translação posterior do condilo medial do femur de 5mm, enquanto a translação do condilo lateral é em media 17mm.

11

Como se comporta a tibia durante a ADM do joelho?

Devido ao padrão de pivo medial do joelho, observa-se que a tibia roda externamente durante a extensão (movimento conhecido como "screw-home mechanism") e internamente durante a flexão.

12

Durante as atividades de vida diaria, quais são os graus de flexão minima requeridos pelo joelho?

Marcha normal = 67o durante a fase de swing
Subir escada = 83o
Descer escada = 90o
Levantar de uma cadeira = 93o

13

Como uma protese com substituição do LCP atinge o femoral rollback?

Essas proteses possuem um poste tibial e um ressalto femoral que se encostam com a flexão do joelho, com o estresse resultante sendo transferido para a interface cimento-osso. Essa transferencia de forças levou alguns autores a sugerirem maiores taxas de falha nesse tipo de protese, o que não ficou comprovado com os estudos comparativos.

14

Qual a função de estabilização do LCP no plano coronal?

Estabilizador secundario. Sua liberação permite menos baleanceamento dos ligamentos colaterais para se obter um gap de flexão-extensão simétrico durante a cirurgia.

15

O que é a patellar clunk syndrome?

Nas PCL-substituting apresenta um cutout para o mecanismo poste que se inicial logo abaixo da troclea do articulação patelofemoral. Osso adicional é removido do femur quando essas proteses são utilizadas para acomodar esse mecanismo box-and-cam. Assim, o grau de flexão no qual a patela toca essa "box" varia ao longo dos diferentes modelos de estabilização posterior. A patela e a sinovia hipertrofica abaixa da superficie do tendão quadriceptal pode se interpor nesse mecanismo. Isso é a petellar clunk syndrome, e é uma complicaão em potencial desses modelos de protese.

16

Qual o grau de valgismo entre os eixos anatomicos do femur e da tibia, normalmente?

6 + ou - 2o

17

Como calcular o eixo mecanico do membro inferior?

O eixo mecanico do membro inferior é definido como uma linha desenhada, em uma radiografia do paciente em pé, do centro da cabeça do femur até o centro do domo talar. Essa linha tipicamente deve se projetar atraves do centro do joelo, descrevendo assim um eixo mecanico neutro. Quando a linha se projeta lateral ao centro do joelho, este está mecanicamente alinhado em valgo. Quando a linha se projeta medial ao centro do joelho, este está mecanicamente alinhado em varo.

18

Quantos graus de valgo o eixo mecanico do joelho está em relação ao eixo vertical do corpo?

3o

19

Quantos graus de valgo está o eixo anatomico em relação ao eixo mecanico do joelho? E em relação ao eixo vertical do corpo?

6 e 9o, respectivamente.

20

Quantos graus de varo encontra-se o eixo anatomico da tibia em relação ao eixo vertical do corpo?

2 a 3o.

21

A partir de quantos graus de varo o componente tibial tende a falahar em varo?

A partir de 5o de implantação em varo do componente tibial. Por isso, geralmente o componente tibial é implantado em neutro no plano coronal, com graus variados de tilt posterior.

22

Quantos graus de valgo é implantado o componete femoral?

Geralmente, 5 a 7o de valgo são necessários para restabelecer o eixo mecanico do membro inferior ao se implantar o componente femoral.

23

Como é determinado o balanço rotacional femoral?

Intraoperatoriamente

24

Quais os efeitos do balanço rotacional femoral?

Efeitos no espaço durante o balanço em flexão e no trecking patelofemoral.

25

Como criar o espaço retangular em flexão equalizado (balanço femoral rotacional)?

Para criar esse espaço, com tensão igual nos ligamentos colaterais medial e lateral, o componente femoral é rodado externamente em média 3o relativos ao eixo condilar posterior.

26

Quando o balanço femoral não pode ser conseguido com a rotação externa de 3o? Como agir diante desses casos?

Quando o condilo femoral apresenta desgaste significante ou quando o condilo femoral lateral é hipoplasico, como é frequentemente visto em deformidades em valgo. Nessas situações o cirurgião pode utilizar o eixo anteroposterior epicondilar de Whiteside.

27

Quais são as tecnicas utilizadas para alinhar rotacionalmente o componente tibial?

Duas tecnicas podem ser utilizadas. A primeira alinha o centro da bandeja tibial com a junção entre o terço medial da tuberosidade tibial com os outros dois terços laterais. A segunda tecnica utiliza componentes experimentais e testa a ADM do joelho, permitindo que a tibia se alinhe com o eixo de flexão do joelho.

28

Qual a principal função da patela?

Aumentar o braço de alavanca do mecanismo extensor ao redor do joelho, aumentando a eficiencia da contração do mecanismo extensor.

29

Com quantos graus de flexão o braço de alavanca do mecanismo extensor é o maior?

20o de flexão

30

Em qual momento a força do quadriceps é mais requisitada?

A força do mecamismo extensor é mais requisitada nos ultimos 20o de extensão do joelho

31

O que é o angulo Q?

O angulo Q é aquele entre o eixo mecanico do femur estendido e a linha entre o centro da patela e a tuberosidade tibial. Membros com aumento do angulo Q tendem a subluxar a petela lateralmente.

32

Como é o contato entre a patela e a troclea?

A superficie articular inferior da patela é a primeira a tocar a troclea, com e flexão de 20o aproximadamente. A porção média da patela articula com a troclea com aproximadamente 60o de flexão, e a parte superior da patela com 90o de flexão. Na flexão máxima, por volta dos 120o, a patela articula somente lateral e medialmente com a troclea. Uma terceira faceta articular geralmente encontra-se presente no aspecto medial da patela, e articula com o aspecto leteral do condilo medial femoral quando o joelho encontra-se fletido mais que 90o.

33

O que acontece com o angula Q com a flexão do joelho?

Diminui, pois a tibia roda internamente;

34

Qual o efeito da mudança da area de contato patelar com a flexão do joelho na TKA?

Um loading excentrico na articulação patelofemoral protetizada resulat em forças "rasantes" (shear) no componente patelar e na interface protese-osso. Essas forças levam a falha do componente metalico patelar, desgaste localizado do polietileno ou soltura do componente.

35

Qual a espessura mínima do polietileno?

A maioria dos estudos recomenda uma espessura de 8mm para evitar estresse de contato alto.

36

Em relação ao tipo de fixação, qual tipo de protese tem maior duração?

Cimentadas

37

Em qual tipo de protese ocorre maior osteolise?

Não-cimentadas

38

Qual a principal indicação de TKA?

Alivio da dor causada por osteoartrose severa, com ou sem deformidade.

39

Quais são as medidas conservadora adotadas para alivio da dor?

AINES, modificação do estilo de vida e uso de muletas para deambular.

40

Que tipo de paciente tende a ter menos satisfação com a TKA?

Pacientes que não tem uma perda completa do espaço articular antes da cirurgia.

41

Com quantos graus de contratura em flexão a marcha começa a ficar prejudicada?

Por volta dos 20o de contratura em flexão

42

Quais são as contra-indicações absolutas para TKA?

Infecção ativa ou recente no joelho, infecção ativa em outro sistema, disfunção ou descontinuidade do mecanismo extensor, deformidade em recurvatum secundaria a fraqueza muscular e presença e artrose funcionante indolor.

43

Em um paciente com indicação de THA e TKA ipsilateral, qual deve ser realizada primeiro?

THA, porque a reabilitação da THA com osteoartose do joelho é mais fácil que TKA com coxartrose.

44

Quais são as duas populações de pacientes com indicação de UKA?

- Idoso magro com artrose unicompartimental;
- Individuos jovens com artrose unicompartimental, nos quais a UKA é utilizada como uma primeira artroplastia, normalmente ao invés de uma osteotomia tibial proximal com artrose isolada no compartimento medial.

45

Quais são as contra-indicações para UKA?

Artrite inflamatória, contratura em flexão de 15o ou mais, ADM pré-operatorio menor que 90o, deformidade angular de mais de 10o com o eixo mecanico em varo ou 5 graus de valgo, significante erosão cartilaginea nas áreas de carga do compartimento oposto, deficiencia do LCA e exposição do osso subcondral patelar. Obesidade é uma contra-indicação relativa.

46

Qual paciente tem indicação para artroplastia patelofemoral?

The ideal candidate for patellofemoral arthroplasty is a patient who is younger than 65 years of age and has debilitating, isolated patellofemoral arthritis with no malalignment of the patellar mechanism. Pain during daily activities that is localized to the patellofemoral joint and is not relieved with nonsteroidal anti-inlammatory medications or injection therapy is a good indication for patellofemoral arthroplasty. Patellofemoral arthroplasty is recommended in patients younger than 65 years of age to provide a conservative, bone-sparing alternative to TKA, which is not desirable in young active patients; there are no published data showing that outcomes of patellofemoral arthroplasty are age dependent.

47

Em relação a evolução da osteoartrose tibiofemoral, qual progride mais rapido?

The progression of tibiofemoral arthritis is more frequent with primary osteo- arthritis than with posttraumatic arthritis or patellofemoral dysplasia.

48

Quais valores são considerados anormais do angulo Q?

Angles of more than 15 degree in men and 20 degrees in women are considered abnormal. Any condition that increases the Q angle increases the lateral displacement forces on the patella and may lead to subluxation or dislocation

49

Mal alinhamento patelofemoral isolado é indicativo de protese patelofemoral?

Patellofemoral arthroplasty alone cannot correct patellar malalignment, and instability of the patellofemoral joint is not an indication for the procedure.

50

Qual é a principal contra-indicaçao de artroplastia patelofemoral?

Artrose tibiofemoral

51

Quais os pacientes não são candidatos a artroplastia patelofemoral?

Patellofemoral arthroplasty also is not indicated in patients with severe coronal deformity of the knee (valgus of more than 8 degrees or varus of more than 5 degrees) unless the deformity is corrected by osteotomy before arthroplasty. Flexion of 120 degrees in the sagittal plane, with less than 10 degrees of lexion contracture, is recommended. Knee joint stifness should be carefully assessed because this patient population has a high rate of previous surgery that increases the frequency of arthroibrosis and patellar height abnormali- ties. Patients with patella baja from quadriceps muscle atrophy or patellar tendon scarring are not good candidates for patel- lofemoral arthroplasty. Although few data exist correlating the outcome of patellofemoral arthroplasty with BMI, currently it is not recommended in obese patients because of concerns about overloading of the implant. A recent study showed a higher rate of revision to TKA in obese patients (BMI > 30) than in nonobese patients, whereas primary diag- nosis, age, or sex did not signiicantly afect the revision rate.

52

Qual a porcentagem de sucesso da artroplastia patelofemoral?

Good-to-excellent 3- to 17-year results have been reported in 66% to 100% of patients

53

Quais as indicações de não se realizar o resurfacing patelar na TKA?

Suggested indications for leaving the patella unresurfaced are a primary diagnosis of osteoarthritis, satisfactory patellar cartilage with no eburnated bone, congruent patel- lofemoral tracking, a normal anatomical patellar shape, and no evidence of crystalline or inlammatory arthropathy.

54

Qual fator parece estar relacionado com a sobrecarga do implante patelar na TKA?

Sobrepeso (IMC)

55

Quais as considerações devem ser levadas em conta na TKA bilateral?

In considering patients for simultaneous bilateral TKA, comorbidities and physiological age should be considered because signiicant cardiopulmonary disease may sway the surgeon toward unilateral procedures. An increased risk of cardiovascular and neurological complications has been noted in patients older than 70 years undergoing simultane- ous bilateral TKA. No increased risks of complications with bilateral TKA have been identiied in patients with a BMI of 30 or more compared with those with a lower BMI. An analy- sis of over 4 million hospital discharges over a 14-year period compared unilateral, bilateral, and revision TKA procedures and found that bilateral TKA had higher complication and mortality rates than either unilateral or revision TKA. Before choosing staged or simultaneous TKA procedures, each patient should be carefully evaluated, considering his or her age, cardiac risk factors, and other comorbidities. he risks associated with both approaches should be thoroughly discussed with the patient before a choice is made.

56

Quais são as categorias da Knee Society Scoring System e suas respectivas pontuações?

Objective Knee Score (7 items, 100 points)
Satisfaction Score (5 items, 40 points)
Expectation Score (3 items, 15 points)
Functional Activity Score (19 items; 100 points)

57

O que a literatura mostra sobre a durabilidade das TKA?

More recently, the reported 15- to 18-year survivorship of a cementless cruciate-retaining TKA was 98.6%, with 79% of patients reporting no pain. Multiple studies of PCL-retaining and PCL-substituting designs have documented 10-year survivorship of 95% or greater. As discussed in the earlier section on component ixation, cementless ixation has had mixed results with respect to prosthesis survivorship. Some designs have equaled the success of cemented designs, whereas others have had higher rates of failure because of tibial loosening, polyethylene wear, and osteolysis.

58

Quais são as radiografias pré-operatorias mais utilizadas?

Preoperative knee radiographs should include a standing anteroposterior view, a lateral view, and a skyline view of the patella.

59

Qual a reserva cardiopulmonar que o paciente a ser submetido a TKA deve ter?

Patients must have adequate cardiopulmonary reserve to withstand general or epidural anesthesia and to withstand a blood loss of 1000 to 1500 mL over the perioperative period.

60

A quais parametros clinicos o ortopedista deve ficar atento no paciente a ser submetido a TKA?

Poor nutrition, frequently present in elderly patients, oten can be detected by a low albumin level in the serum (<3.5 mg/dL). Patients with total lymphocyte counts of less than 1200 cells/mL also have been shown to have higher hospital charges, longer hospital stays, and longer anesthesia and surgery times than those with higher counts. Patients with type II diabetes should have a hemoglobin A1C test preoperatively and their blood glucose level should be under good control. Smoking cessa- tion should be encouraged to decrease the risk of morbidity ater total joint arthroplasty.

61

Qual incisão mais comumente utilizada?

Anterior medial

62

Qual problema a maioria das vias de acesso para realização de TKA pode resultar?

General most incisions will compromise the infrapatellar branch of the saphenous nerve and result in an area of numbness on the outer aspect of knee.

63

Qual a incisão retinacular padrão?

The standard retinacular incision in TKA is a medial parapatellar retinacular approach.

64

Qual cuidado se deve ter ao se aplicar tensão ao mecanismo extensor?

During all maneuvers that place tension on the extensor mechanism, especially knee lexion and patellar retraction, pay careful attention to the patellar tendon attachment to the tibial tubercle. Avulsion of the patellar tendon is dificult to repair and can be a devastating complication.

65

Como é realizado o "southern aproach"da retinacula?

The subvastus (“Southern”) approach difers from the medial parapattelar in the method of subluxating the extensor mechanism laterally for knee exposure. The same anterior midline knee incision is used, but the proximal retinacular incision is performed by incising the supericial fascia overlying the vastus medialis and bluntly mobilizing the distal medial border of the vastus medialis posteriorly to the medial intermuscular septum. The origin of the vastus medialis is lited of the medial intermuscular septum to approximately 10 cm proximal to the adductor tubercle, staying distal to the aperture for the femoral vessels. The synovium is incised, and the entire extensor mechanism is dislocated laterally.

66

Quais os argumentos dos defensores do "southern approach"?

Advocates of this approach claim that leaving the extensor mechanism intact results in a more rapid return of quadriceps strength, preserves more of the vascularity to the patella, improves patient satisfaction while decreasing postoperative pain, and decreases the need for lateral release. Compared with the medial parapatellar approach, the exposure may be limited, especially in obese patients and patients with previous knee surgeries.

67

Quais as caracteristicas do "midvastus approach" e suas contra-indicações relativas?

The midvastus approach, which difers from the subvastus approach in that the vastus medialis muscle is split in line with its fibers, rather than subluxated laterally in its entirety. The split in the vastus medialis starts at the superomedial border of the patella and extends proximally and medially toward the intermuscular septum. A safe zone of 4.5 cm of the vastus medialis can be sharply split from the margin of the patella and can be bluntly dissected further if desired. This approach preserves the supreme genicular artery to the patella and the quadriceps tendon. Relative contraindications to the midvastus approach include obesity, previous upper tibial osteotomy, and preoperative lexion of less than 80 degrees.

68

Quais são os princípios do preparo osseo da TKA?

Appropriate sizing of the individual components, alignment of the components to restore the mechanical axis, re-creation of equally balanced soft tissues and gaps in flexion and extension, and optimal patellar tracking.

69

Quais os metodos para se determinar a rotação do componete femoral?

Femoral component rotation can be determined by one of several methods. The transepicondylar axis, anteroposterior axis, posterior femoral condyles, and cut surface of the proximal tibia all can serve as reference points. Figura 7-35

70

Como realizar o corte femoral utilizando-se o eixo transepicondilar femoral?

If the transepicondylar axis is used, make the posterior femoral cut parallel to a line drawn between the medial and lateral femoral epicondyles. Determine the antero- posterior axis by drawing a line between the bottom of the sulcus of the femur and the top of the intercondylar notch, and make the posterior femoral cut perpendicular to this axis

71

Como realizar o corte femoral utilizando-se o eixo condilar posterior?

When the posterior condyles are referenced, make the cut in 3 degrees of external rotation off a line between them. A valgus knee with a hypoplastic lateral femoral condyle may lead to an internally rotated femoral component if the posterior condyles alone are referenced (Fig. 7-36).

72

Como realizar o corte tibial?

Cut the tibia perpendicular to its mechanical axis with the cutting block oriented by an intramedullary or extra- medullary cutting guide. The amount of posterior slope depends on the individual implant system being used. Many systems incorporate 3 degrees of posterior slope into the polyethylene insert, which allows more accurate slope to be aligned by the implant rather than with the cutting block.

73

Como proceder se o gap de extensão for menor que o gap de flexão?

If the extension gap is smaller than the lexion gap, remove more bone from the distal femoral cut surface, or release the posterior capsule from the distal femur, but first make certain that all posterior condylar osteophytes have been removed before raising the joint line.

74

Como proceder se o gap de flexão for menor que o gap de extensão?

If the lexion gap is smaller than the extension gap, remove more bone from the posterior femoral condyles by making appropriate cuts for the next smaller available femoral component; make sure this is done with anterior referencing so that the posterior condyles are shortened and the anterior cortex is not notched.

75

Como proceder se o gap de flexão e extensão estiver equalizado, porém o espaço para a protese for pequeno?

If the lexion and extension gaps are equal, but there is not enough space for the desired prosthesis, remove more bone from the proximal tibia because bone removed from the tibia affects the lexion and extension gaps equally.

76

Onde se localiza o ponto de entrada da haste do componente femoral da TKA?

The entry portal for the femoral alignment rod typically is placed a few millimeters medial to the midline, at a point anterior to the origin of the PCL.

77

Quando se utiliza o alinhamento femoral extramedular?

Extramedullary femoral alignment is useful only in limbs with severe lateral femoral bowing, femoral malunion, or stenosis from a previous fracture, or when an ipsilateral total hip replacement or other hardware ills the intramedullary canal.

78

Qual consenso sobre o uso de guia intramedular para o alinhamento tibial?

Risco de embolia gordurosa

79

Quais as vantagens da protese navegada?

Computer navigation systems also can aid in determin- ing the proper implant size as well as alignment. Sot tissue balancing and measurement of lexion and extension gaps during the procedure are other signiicant advantages to computer-assisted TKA. Objective measurement of the gaps ensures proper sot tissue balancing and gaps that will provide a stable joint throughout a range of motion. A gap balancing and equalization technique was found to produce better lexion at 1- to 4-year follow-up, but no patient-derived outcome measures were diferent than those with conven- tional techniques. In a meta-analysis of 22 studies of computer-assisted TKA, better overall alignment and implant positioning were found but no improvement in functional outcome was noted. A recent prospective study randomized 195 patients to TKA with conventional instrumentation (97 knees) or computer-assisted navigation (98 knees). At 5-year follow-up Knee Society scores were significantly higher in the navigated group, possibly suggesting that the efects of computer assistance may not be apparent until farther along in the survivorship curves of TKA patients.
Another advantage of computer navigation is avoidance of violation of the femoral intramedullary canal, which may reduce blood loss and cardiac-related complications because fewer emboli are placed into the venous system than with placement of an intramedullary alignment rod.

80

Quais as desvantagens da protese navegada?

Disadvantages of computer navigation systems include the cost of the system, increased operating times, and the lack of current clinical outcome studies showing improved survivorship.

81

Antes de se realizar o balanço ligamentar, qual procedimento deve ser realizado?

Before release of any anatomical sot tissue sup-porting structure about the knee, all peripheral osteophytes should be removed from the femur and tibia. If a tibial resection first technique is being done, the osteophytes should be removed before determining any bony cuts on the femur.

82

Qual o valor a ser atingido no balanço varo-valgo?

As a general guideline, 1 to 2 mm of balanced varus-valgus play in the prosthetic knee is a reasonable goal.

83

Em relação ao balanço ligamentar, a liberação de quais estruturas afetam o espaço em extensão e em flexão?

In general, release of the posterior structures from the posterior oblique ligament to the posterior capsule and semimembranosus insertion on the tibia afects the extension space more than the lexion space, and release of the anterior half of the superficial medial collateral and the pes anserinus insertion afects the flexion space more.

84

Qual a deformidade mais comum do joelho com osteoartrose?

Deformidade em varo

85

Quais são os pacientes que apresentam deformidade em valgo do joelho?

Valgus deformity is common in patients with rheumatoid and inflammatory arthropathies and also can occur in those with hypoplastic lateral femoral condyle or previous trauma or reconstructive procedures that change the weight-bearing axis of the lower extremity or tighten the lateral side of the joint.

86

Qual a ordem de liberação das estruturas laterais para o balanceamento do valgo do joelho?

The structure released first depends on whether both the extension and flexion gaps are tight on the lateral side. If both are tight, release the lateral collateral ligament off the lateral epicondyle, taking care to leave the insertion of the popliteus tendon intact. If at any point during the balancing of the valgus knee only the extension gap is tight, release the iliotibial band by a Z-lengthening or pie-crusting of the band 2 cm above the joint line. Make certain all ibers are released, and evaluate the biceps aponeurosis to make sure it is not involved in the contracture.
Release of the posterolateral corner has been shown to effectively increase the extension space more than the flexion space and should be considered before release of the lateral collateral ligament if only a small amount of correction is needed.
If the knee is still not balanced in full extension after release of all of these structures, release the posterior capsule off the lateral femoral condyle; then release the lateral head of gastrocnemius if further correction is needed.

87

Liberação do tendão popliteo aumenta qual dos gaps?

Release of the popliteus tendon will increase the flexion gap laterally more than the extension gap.

88

Como proceder se a liberação de todas as estruturas laterais não produzirem balanço de flexão-extensão equalizado?

If complete release of all of the above structures does not balance the lexion and extension gaps on the lateral side, consider advancement of the medial collateral ligament.

89

Quais as vantagens da tecnica de pie-crusting?

The advantage of pie-crusting, especially on the lateral soft tissue sleeve, is that it leaves a supporting tether that does not allow a larger gap opening on the lateral side of knee in lexion.

90

Qual cuidado deve ser tomado na realização do pie-crusting?

Care is needed when pie- crusting is done in the posterolateral corner because the peroneal nerve is within 1.5 cm. Because the nerve is farther away when the knee is flexed, flexing the knee can help protect the nerve during pie-crusting of the postero- lateral corner.

91

Como proceder em relação a correção da contratura em flexão do joelho na TKA?

Most preoperative flexion deformities improve with appropriate soft tissue balancing for coronal plane deformity. If a flexion contracture persists despite balanced medial and lateral soft tissues, the shortened posterior structures must be effectively lengthened. If the contracture persists, the joint line may need to be elevated by increasing the amount of distal femoral bone resection.
With severe lexion contracture, elevation of the joint line more than 4 mm should be avoided because it can create mid-flexion instability, and an increase in implant constraint may be necessary.

92

Qual a controversia existente em relação a correção da contratura em flexão do joelho da TKA?

Because average residualf lexion contractures of 15 degrees tended to improve to 3 degrees at 4.5-year follow-up, some authors have advocated posterior release and osteophyte removal only with no additional distal femoral bone resection, whereas others found that the maximal correction of a flexion contracture occurred in the operating room and did not improve with time.

93

O que acontece com a contratura em flexão caso o LCP seja liberado?

O contratura aumenta, aumentando também a disparidade com o gap de extensão.

94

A deformidade em recurvatum geralmente ocorre com qual outro tipo de deformidade do joelho?

Recurvatum often occurs in conjunction with a valgus knee deformity caused by a hypoplastic lateral femoral condyle that allows a larger extension space.

95

Qual tipo de implante deve ser utilizado em deformidades em recurvatum? Por que?

A hinged implant with an extension stop may be needed to compensate for the loss of quadriceps power.

96

Como proceder diante de deformidades em recurvatum?

Although possibly counterintuitive, using a smaller femoral component referenced from the anterior aspect of the femur requires removal of more posterior femoral condylar bone, which will increase the flexion gap. This will allow the height of the tibial polyethylene component to be used to fill the gap and create a joint space that is stable in extension and flexion.

97

Qual a importancia do balanceamento do LCP nas proteses PCL-retaining?

A PCL that is too tight in flexion can lead to poor postoperative knee flexion or excessive femoral rollback, which is thought to be a factor in accelerated polyethylene wear. Conversely, if the PCL does not develop adequate tension in flexion, femoral rollback does not occur. Accurate balancing of the PCL is necessary for optimal functioning and longevity of a PCL-retaining prosthesis.

98

Como deve estar posicionada a patela nos testes de balanceamento do LCP?

The patella should be located within the trochlear groove during this and other tests of PCL tension because the everted patella externally rotates the tibia in lexion and can lead to a false-positive result.

99

Qual fenomeno deve ser observado durante o rollback femoral em flexão?

the tibiofemoral contact point should not move onto the posterior third of the tibial articular surface.

100

Como é realizado o teste de pressão digital no LCP?

With the knee in 90 degrees of flexion, firm digital pressure should cause the PCL to deflect 1 to 2 mm.

101

Quais os tipos de defeitos ósseos encontrados na TKA?

Contained or cavitary defects have an intact rim of cortical bone sur- rounding the deficient area, whereas noncontained or segmental defects are more peripheral and lack a bony cortical rim.

102

Como Rand classificou os tipos de defeitos ósseos na TKA?

Rand classified these defects into three types:
Type I: focal metaphyseal defect, intact cortical rim
Type II: extensive metaphyseal defect, intact cortical rim
Type III: combined metaphyseal and cortical defect
Small defects (<5 mm) typically are filled with cement. Contained defects can be filled with impacted cancellous bone grat. Larger noncontained defects can be treated by a variety of methods, including the use of structural bone grafts, metal wedges attached to the prosthesis, or screws within cement that fills the defect.

103

Como a fixação dos componentes tibial e femoral em rotação interna pode afetar o tracking patelofemoral?

Internal rotation of the tibial component lateralizes the tibial tubercle, increasing the Q angle and the tendency to lateral patellar subluxation. Similarly, internal rotation or medial translation of the femoral component can increase lateral patellar subluxation by moving the trochlea medially. If the patella is to be resurfaced, the prosthetic patella should be medialized to approximate the median eminence of the normal patella, rather than simply centering the prosthetic button on the available bone.

104

O que é o "no thumb test"?

The “no thumb” test of patellar tracking should be used as a guide of adequate patellar stability. The reduced patella is observed within the femoral trochlea throughout the range of knee motion before retinacular closure. If the patellar button tracks congruently with minimal or no pressure applied to the lateral side of the patella, patellofemoral track- ing is adequate. If the patella tends to subluxate, the knee should be inspected for the previously discussed causes of patellar subluxation.

105

Qual manobra deve ser realizada na tentativa de se evitar o release retinacular lateral por maltracking da patela?

Lowering the tourniquet and reassessing patellar tracking before lateral retinacular release have been shown to avoid an unnecessary lateral retinacular release.

106

Qual o grande risco de se realizar o release lateral para melhorar o trecking patelar?

The greatest risk in lateral release is devascularization of the patella caused by interruption of the superior lateral geniculate artery.

107

Qual a profundidade que o cimento deve atingir no osso esponjoso para que se obtenha uma fixação adequada?

Impaction of the tibial prosthesis generally results in intru-sion of early dough-phase cement to a depth of 2 to 5 mm in cancellous bone, which is suficient for long-term fixation, as shown by Insall and others.
In addition to range-of-motion exercises, the postoperative rehabilitation protocol includes lower extremity muscle strengthening, concentrating on the quadriceps; gait training, with weight bearing as allowed by the particular knee recon- struction; and instruction in performing basic activities of daily living.

108

Como deve ser realizado o fechamento da via de acesso?

After hemostasis is obtained, the retinacular incision is closed, taking care to approximate the elevated periosteal tissues to the patellar tendon. The knee should be flexed past 90 degrees to ensure that no part of the closure limits flexion, and that the patella tracks normally. he subcutaneous tissue and skin are closed with the knee in 30 to 40 degrees of flexion to aid in skin flap alignment.

109

Como deve ser feito o manejo pós-operatorio da TKA?

Initially, a compressive dressing is worn to decrease postoperative bleeding and a knee immobilizer may be used until quadriceps strength is adequate to ensure stability during ambulation. Range-of-motion exercises are performed postoperatively, with or without the assistance of a continuous passive motion machine. Continuous passive motion has been shown in multiple studies to assist in obtaining knee flexion more quickly, which may decrease the length of stay in the hospital. Continuous passive motion has not been proved to afect the prevalence of DVT, long-term knee range of motion, or knee functional scores.

110

Quais os fatores citados como contribuintes para o mal resultado de TKA pós osteotomia proximal da tibia?

Presence of patella infera, dificulties in exposure, and poor lateral skin flap vascularity.

111

Qual a distancia minima entre uma incisão lateral para osteotomia proximal da tibia previa e uma nova incisão para a TKA?

An adequate intervening skin bridge of at least 8 cm must be let between new midline and old lateral incisions.

112

Qual o melhor tipo de protese para pacientes que sofreram patelectomia total previa?

Comparison of the results of TKA after patellectomy in patients treated with PCL-retaining and PCL-substituting prostheses with a control group of TKA patients without previous patellectomy found that Knee Society scores were greater for PCL-substituting designs, whereas PCL-retaining knees showed greater antero-posterior instability.

113

Como funciona o "four-bar linkage system"?

FIGURE 7-60 Four-bar linkage system of cruciate ligaments reveals that patellar tendon is roughly parallel to PCL and quadriceps tendon is roughly parallel to ACL at 30 degrees of lexion when patella is engaged with trochlear groove. Loss of patella results in alteration of extensor mechanism moment arm and loss of contraction strength of quadriceps. The resultant vector of the force exerted on the tibial tubercle by the patellar tendon changes ater patellectomy, and not only is there less of a moment arm imparted by the extensor mechanism but also a more posterior force on the tibia results from the loss of the patella.

114

Qual o tipo de protese indicado na neuropatia de Charcot e quais os cuidados pós-operatórios devem ser tomados?

Because of the propensity of Charcot knees to develop early postoperative dislocation and progress to symptomatic instability, they recommended the use of a rotating hinge prosthesis and post- operative protection with a knee brace or immobilizer to prevent early dislocation.

115

Quais complicações podem estar presente pós-TKA em pacientes hemofilicos?

Significant postoperative complications after TKA in hemophilic patients include hemorrhage, superficial skin necrosis, nerve palsies, and deep infection. Because a perioperative factor VIII level of less than 80% has been associated with a greater probability of complications, the perioperative factor VIII level should be maintained at 100%.

116

Qual a maior complicação de pacientes com HIV pós-TKA e sua taxa de incidencia?

The most common complication after TKA in these patients is infection, with reported rates of 30%.

117

Quais as complicações relacionadas a TKA em pacientes diabeticos?

TKA in diabetic patients is associated with an increased wound complication rate, increased infection, and more frequent revisions, with no significant diferences noted between insulin-dependent and non–insulin-dependent diabetics.

118

Qual a incidencia de artropatia inflamatoria em pacientes com psoriase?

An inflammatory arthritis similar to rheumatoid arthritis develops in approximately 7% of patients with psoriasis.

119

Quais os fatores relacionados com TVP pós-TKA?

Factors that have been correlated with an increased risk of DVT include age older than 40 years, estrogen use, stroke, nephrotic syndrome, cancer, prolonged immobility, previous thromboembolism, congestive heart failure, indwelling femoral vein catheter, inflammatory bowel disease, obesity, varicose veins, smoking, hypertension, diabetes mellitus, and myocardial infarction.

120

Qual é o exame padrão-ouro para se dectar TVP?

Venography is the classic radiographic method of detection of DVT and is still considered the gold standard, especially for research purposes.

121

Quais os riscos relacionados a venografia? Que método diagnostico pode substituir esse exame?

Venography carries the risk of anaphylactic reaction to the contrast media and a small risk of inducing DVT. Duplex ultrasound has been reported as an alternative method of diagnosis of DVT after total joint arthroplasty, with documented sensitivities of 67% to 86% using venography for comparison.

122

O que pode ocorrer com o uso de heparina de baixo peso molecular e anestesia epidural ou raquianestesia?

Low-molecular-weight heparin with epidural or spinal anesthesia must be used with extreme caution because epidural hematomas with disastrous neurological complications have been reported. The time of utmost risk apparently occurs on postoperative day 3 when the indwelling catheter is removed from a patient being treated with low-molecular-weight heparin for DVT prophylaxis. Guidelines from the American College of Chest Physicians in 2008 recommend that low-molecular-weight heparin, fondaparinux, or a vitamin K antagonist (e.g., warfarin) be used for DVT prophylaxis in TKA patients for a minimum of 10 days.

123

Qual a nova droga recentemente aprovada pelo FDA para profilaxia de TVP nas TKA?

The FDA recently approved an oral factor Xa inhibitor (rivaroxaban) for DVT prophylaxis ater TKA.

124

Qual a complicação citada nos estudos relacionados com o rivaroxaban?

A return to the operating room because of wound complications was required in approximately twice as many patients taking rivaroxaban as in those taking low-molecular-weight heparin.

125

Qual a taxa de incidencia de infecção nas TKA nas series longas?

frequencies of 2% to 3% in several large series.

126

Segundo o Medicare, qual a incidencia de infecção de TKA nos 2 primeiros anos de PO?

According to current Medicare data, 1.5% of patients develop a periprosthetic infection in the first 2 years after TKA.

127

Quais são os fatores pré-operatorios relacionados a infecção pós-operatoria de TKA?

Preoperative factors associated with a higher rate of infection after TKA include rheumatoid arthritis (especially in seropositive men), skin ulceration, previous knee surgery, use of a hinged-knee prosthesis, obesity, concomitant urinary tract infection, steroid use, renal failure, diabetes mellitus, poor nutrition, malignancy, and psoriasis.

128

Qual alteração realizadas nas salas operatorias diminuiram a incidencia de infecção pós TKA?

The use of filtered vertical laminar low operating rooms, body exhaust suits, and prophylactic antibiotics has greatly reduced postoperative infection rates in total joint arthroplasty.

129

Quais os microorganismos mais comumentes isolados nas infecções de TKA e qual a classe de antibioticos de escolha para a profilaxia?

Because the most common organisms causing post-operative infection are Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus species, the usual choice of prophylactic antibiotic is a first-generation cephalosporin, such as cefazolin.

130

Qual o antibiotico de escolha em pacientes alergicos a penicilina?

Vancomicina

131

Quando suspeitar de infecção de TKA?

Infection should be considered in any patient with a consistently painful TKA or an acute onset of pain in the setting of a previously pain-free, well-functioning arthroplasty. A history of subjective swelling, erythema, or prolonged wound drainage suggests TKA sepsis, but these signs are not uniformly present. Swelling, tenderness, painful range of motion, erythema, and increased warmth of the afected limb may accompany a TKA infection.

132

Qual o marcador laboratorial mais sensivel para infecção de TKA?

The C-reactive protein level is a more reliable marker for infection because it typically returns to normal in a reliable manner. The interleukin-6 level has been found to be a reliable indicator of infection affecting hip or knee arthroplasty, with 100% sensitivity and 95% speciicity.

133

Qual o exame padrão para detectar infecção na TKA?

Aspiration remains the standard for diagnosing infection in TKA, although the reported sensitivity ranges from 45% to 100%. This sensitivity can be improved by repeated aspiration and by deferring aspiration for 2 weeks in patients taking systemic antibiotics. he luid cell count obtained at aspiration can be helpful, with a white blood cell count of more than 2500 cells/mm and 60% polymorphonuclear cells indicative of probable infection.

134

Quando manter a protese em caso de infecção?

Joint débridement with prosthesis retention is similarly limited to a small subset of patients: patients with an early (4 weeks postoperatively, acute onset of symptoms) with a well-fixed prosthesis. Infection with S. aureus is another relative contraindication to débride- ment and component retention. (Classificação de Segawa)

135

Quais as complicações patelofemorais na TKA?

Complications include patellofemoral instability, patellar fracture, patellar component failure, patellar component loosening, patellar clunk syndrome, and extensor mechanism rupture.

136

Quais são os fatores relacionados com fratura de patela pós-TKA?

Patellar fracture has been correlated with multiple factors, including excessive patellar resection, vascular compromise secondary to lateral release, patellar maltracking secondary to component malposition, excessive joint line elevation, knee flexion of more than 115 degrees, trauma, thermal necrosis from PMMA polymerization, and revision TKA.

137

Como é a classificação de fratura periprotetica patelar e seu manejo?

Periprosthetic patellar fractures have been classiied according to the integrity of the extensor mechanism and stability of the implant. Fractures associated with an intact extensor mechanism and stable implant (type I) should be treated nonoperatively with a knee immobilizer or cylinder cast for 6 weeks. Displaced fractures with extensor mechanism discontinuity (type II) should be treated operatively. Transverse middle-third fractures are treated with tension band wiring and retinacular repair. Loose patellar components (type III) should be excised and not replaced because this may impair fracture healing. Stable patellar components that impair fracture fixation also should be removed. Proximal or distal pole fractures should be treated with partial patellectomy and suture repair. Postoperative rehabilitation and range of motion are based on the stability of the fixation achieved at the time of surgery. Patellectomy and extensor mechanism repair are indicated when extreme comminution or poor bone stock preclude stable bony ixation. Patients should be cautioned when operative intervention is recommended because complication rates are high.

138

Quais sinais clinicos sugerem falha do componente patelar?

Clinically, the onset of a knee efusion, patellofemoral crepitus, or audible squeaking and scraping all suggest component failure.

139

Qual é a incidencia de perda do componente patelar nas TKA?

Patellar component loosening occurs in 0.6% to 2.4% of arthroplasties.

140

O que é o "patellar clunk syndrome"?

Patellar clunk syndrome was described by Hozack et al. in association with posterior-stabilized knee arthroplasties. A fibrous nodule forms on the posterior surface of the quadriceps tendon just above the superior pole of the patella (Fig. 7-72). This nodule can become entrapped in the intercondylar notch of the femoral prosthesis and cause the knee to pop or “clunk” at 30 to 45 degrees of knee flexion as the knee is actively extended.

141

Qual a conduta no "patellar clunk syndrome"?

The recommended treatment for this condition is arthroscopic débridement of the nodule.
Insall recommended a limited synovectomy of the posterior surface of the quadriceps tendon as a prophylactic measure for this condition when performing a posterior-stabilized arthroplasty.

142

Qual a incidencia, as possiveis causas e o manejo da ruptura do mecanismo extensor pós-TKA?

Rupture of the quadriceps or the patellar tendon is an infrequent but severe complication of TKA, occurring in 0.1% to 0.55% of patients. Quadriceps rupture may be related to lateral release in part because of vascular compromise of the tendon and possibly extension of the release anteriorly that weakens the tendon. Nonoperative treatment is recommended for partial tears. Surgical repair is advocated for complete tears, although the results are suboptimal, with frequent diminished range of motion, weakness, extensor lag, and rerupture.

143

Qual é o manejo recomendado para ruptura do tendão patelar pós-TKA?

If patellar bone stock allows, distal primary repair seems warranted with the addition of a tension band wire from the proximal patella to the tibial tubercle or hamstring augmentation or both. When the patella is absent or insuicient for distal repair, extensor mechanism allograt reconstruction or gastrocnemius muscle lap should be considered in centers that have experience with these techniques.

144

Qual é a taxa de lesão arterial na TKA e a taxa de amputação associada?

Arterial compromise ater TKA is a rare but devastating complication that occurs in 0.03% to 0.2% of patients, with 25% resulting in amputation.

145

Qual é a paralisia neurológica mais comum na TKA?

Peroneal nerve palsy is the only commonly reported nerve palsy after TKA, with a reported prevalence of less than 1% to nearly 2%. The true incidence may be higher because mild palsies may recover spontaneously and not be reported. Peroneal nerve palsy occurs primarily with correction of combined fixed valgus and flexion deformities, as are common in patients with rheumatoid arthritis. Suggested risk factors for peroneal palsy ater TKA include postoperative epidural anesthesia, previous laminectomy, tourniquet time of more than 90 minutes, and valgus deformity. When a peroneal nerve palsy is discovered postoperatively, the dressing should be released completely and the knee should be lexed. Such conservative measures, although appropriate, are not efective in restoring nerve function. The value of intraoperative exposure and possible decompression of the peroneal nerve is questionable.

146

Qual o manejo da infecção tardia de TKA mais recomendado na literatura?

More commonly, exchange arthroplasty is done in two stages: initial prosthesis removal and débridement followed by a period of intravenous antibiotics and later reimplantation. The most commonly accepted protocol calls for 6 weeks of intravenous antibiotics, maintaining a minimal bactericidal titer of 1 : 8, followed by reimplantation of another prosthesis. Success rates reported with this protocol range from 89% to 100% and may depend on the bacterial species.

147

Qual a incidencia de fratura supracondileana do femur pós TKA? Quais são os fatores de risco?

Supracondylar fractures of the femur occur infrequently ater TKA (0.3% to 2%). Reported risk factors include anterior femoral notching, osteoporosis, rheumatoid arthritis, steroid use, female gender, revision arthroplasty, and neurological disorders. The anterior femoral flange of condylar-type prostheses creates a stress riser at its proximal junction with the relatively weak supracondylar bone.
In a biomechanical study and review of the literature, Lesh et al. reported that 30.5% of periprosthetic supracondylar femoral fractures were associated with a notched femur.

148

Como é a classificação de Rorabeck, Angliss, and Lewis para fraturas periproteticas pós TKA e o manejo dessas fraturas?

Rorabeck, Angliss, and Lewis classiied supracondylar periprosthetic femoral fractures on the basis of fracture displacement and implant stability and proposed a corresponding treatment algorithm:
Type I: undisplaced fracture, prosthesis stable
Type II: displaced fracture, prosthesis stable
Type III: unstable prosthesis with or without fracture displacement

149

Como são classificadas as fraturas tibiais pós-TKA?

Tibial fractures below TKAs are uncommon. Felix, Stuart, and Hanssen classified these fractures on the basis of their location, implant stability, and timing (intraoperative vs. postoperative) (Fig. 7-78). Fractures associated with loose implants are treated with revision, bone grating, and stemmed implants as needed. Nondisplaced, stable fractures with well- ixed implants are treated nonoperatively; displaced fractures with well-ixed implants are treated with internal fixation.

150

Quais são os fatores de perda asseptica da TKA?

Component loosening, polyethylene wear with osteolysis, ligamentous laxity, periprosthetic fracture, arthrofibrosis, and patellofemoral complications.

151

Qual componente falha com mais frequencia em solturas assepticas?

To date, tibial component loosening has been more common than femoral component loosening. It has been associated with malalignment of the limb, ligamentous laxity, duration of implantation, patients with high activity demands, polyethylene wear, and excessive component constraint.

152

Como identificar a soltura asseptica pela radiografia?

Aseptic loosening of either component may be apparent on radiograph as a complete radiolucent line of 2 mm or more around the prosthesis at the bone-cement interface in cemented arthroplasty.

153

Como o desgaste do polietileno pode provocar a falha da TKA?

Polyethylene wear can cause failure of TKA by contributing to loosening and osteolysis or more rarely by catastrophic failure through polyethylene fracture.

154

Quais as principais causas de instabilidade da TKA?

The main causes of instability are ligamentous imbalance and incompetence, malalignment and late ligamentous incompetence, deficient extensor mechanism, inadequate prosthetic design, and surgical error.

155

Qual incisão utilizada nas revisões de TKA?

Operative exposure in revision TKA should use the previous TKA skin incision if possible.
When two previous incisions already exist, the more lateral of the two should be selected if possible because of the more favorable superficial blood supply from the medial side of the knee.

156

Qual o manejo pós-operatório da revisão de TKA?

Postoperatively, ambulation should be allowed only in a hinged-knee brace, locked in extension, for 2 to 3 months. The brace is unlocked for active lexion within the “safe” range and passive extension with quadriceps-setting exercises is begun 3 weeks postoperatively. At 6 weeks, active knee extension against gravity alone is allowed along with progression of active and passive flexion.

157

Quantas amostras de cultura em infecção de TKA?

7 amostras

158

Qual a diluição de antibiotico com cimento?

2g de ATB para cada 40g de cimento