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Fratura periprotética (joelho)

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Updated Sep 2026
Illustration: knee

Esta página foi traduzida automaticamente e ainda não foi verificada por um médico. A versão em inglês é a versão oficial.

O que você está sentindo

Uma fratura ao redor de uma prótese de joelho significa que o osso próximo ao implante se quebrou. A dor geralmente é sentida logo acima ou abaixo do joelho, na parte inferior da coxa ou na parte superior da perna. No início, costuma ser aguda, evoluindo para uma dor profunda e contínua. Ficar em pé, caminhar e dobrar o joelho geralmente pioram a dor; o repouso com a perna apoiada costuma aliviá-la.

A dor pode piorar à noite ou ao começar a se movimentar depois de ficar sentado ou deitado. Muitas pessoas percebem a dor com mais intensidade ao acordar e dar os primeiros passos. Levantar-se de uma cadeira, subir escadas, caminhar até a caixa de correio e entrar ou sair do carro podem se tornar difíceis. Você pode não confiar que a perna suportará seu peso, por isso evita colocar todo o peso sobre ela.

Esse tipo de fratura pode afetar sua vida muito além do período de cicatrização. A qualidade de vida pode permanecer reduzida por até 12 meses após a lesão, mesmo quando a fratura já estiver consolidada. Esse é um padrão normal, não um sinal de que algo está errado no processo de recuperação.

Essas fraturas ocorrem com mais frequência em idosos cujos ossos estão menos resistentes do que antes. São pouco comuns, mas, quando acontecem, exigem tratamento cuidadoso. Seu cirurgião analisará atentamente seus exames de raio-X e fará uma anamnese completa para descartar infecção ao redor da prótese antes de decidir o tratamento. Na maioria dos casos, a fratura pode ser tratada mantendo o osso imóvel enquanto cicatriza, deixando a prótese de joelho no lugar. A cirurgia para troca da prótese só é considerada quando ela está solta ou desalinhada.

O que está realmente acontecendo

A prótese de joelho fica inserida no osso, como uma vareta colocada num poste de cerca. A parte metálica é resistente, mas é o osso ao seu redor que mantém tudo firme. Em uma fratura periprotética, esse osso circundante se quebra, enquanto a prótese permanece no lugar. Geralmente, a fratura ocorre logo acima da prótese, no fêmur, ou logo abaixo dela, na tíbia.

Essas fraturas tendem a acontecer em ossos que, com o tempo, se tornaram mais finos e fracos. Algumas condições de saúde e o uso prolongado de comprimidos de esteroides também podem reduzir a capacidade do osso de segurar firmemente o implante. Às vezes, o osso próximo à prótese se desgasta lentamente, deixando menos massa óssea para suportar a carga. Quando um osso enfraquecido é submetido a um tropeço ou queda, ele pode quebrar, enquanto um osso mais forte permaneceria intacto.

A dor que você sente se deve ao fato de o osso fraturado se mover ligeiramente a cada vez que você carrega o peso da perna. Ao ficar em pé ou caminhar, as extremidades da fratura são pressionadas uma contra a outra; por isso esses movimentos causam mais dor. O joelho também pode parecer instável, pois o osso que sustenta a prótese já não se move como uma única peça sólida junto com o restante da perna.

O cirurgião irá analisar cuidadosamente os seus raios-X, pois o metal da prótese pode ocultar a linha da fratura numa radiografia convencional. Caso as imagens não sejam claras, um cintilograma ósseo pode ajudar a identificá-la. Essas fraturas são raras, ocorrendo em apenas uma pequena porcentagem dos pacientes com prótese de joelho; porém, quando acontecem, exigem tratamento cuidadoso. A maioria pode ser tratada mantendo o osso imóvel enquanto cicatriza, mantendo a prótese no lugar. A substituição do próprio implante só é considerada quando ele se solta ou fica desalinhado.

O que podemos fazer a respeito

Como esse tipo de fratura é uma lesão estrutural, geralmente recomenda-se a cirurgia imediatamente, em vez de tentar tratamento conservador primeiro. Deixar o osso se curar sozinho raramente é uma opção para essas fraturas. O objetivo principal é manter o osso quebrado imóvel durante a cicatrização, mantendo a prótese de joelho no lugar. Antes de qualquer operação, verificamos cuidadosamente se há infecção ao redor da prótese, pois isso influencia o procedimento a ser realizado.

A cirurgia principal chama-se redução aberta e fixação interna: o osso é reposicionado e fixado com uma placa metálica e parafusos. Para fraturas logo acima da prótese, no fêmur, costuma-se usar uma placa bloqueável; seus parafusos travam na própria placa, garantindo maior estabilidade em ossos mais finos. Outra opção para certas fraturas do fêmur é a inserção de uma barra dentro do canal ósseo. Ambas as técnicas mantêm o osso estável enquanto cicatriza; discutiremos qual delas é mais adequada para a sua fratura.

Para fraturas logo abaixo da prótese, na tíbia, a placa pode, às vezes, ser inserida por meio de dois pequenos cortes, em vez de uma incisão longa. Isso preserva a área da fratura, protegendo o suprimento sanguíneo necessário para a cicatrização. Em poucos casos, quando o osso é muito fino, pode-se usar um fixador externo, que mantém o osso estável a partir do lado de fora da perna.

Se o osso ao redor da prótese estiver desgastado ou desintegrado na região da fratura, pode não haver massa óssea suficiente para fixação da placa. Nesses casos, opções incluem o uso de osso doador para reforçar a reparação ou a substituição da extremidade inferior do fêmur por um novo implante. Esta última opção é uma cirurgia mais complexa, porém permite que o paciente apoie peso na perna imediatamente.

Um pequeno número dessas fraturas afeta a rótula. Geralmente, essas lesões são tratadas sem cirurgia, com repouso e suporte até que o osso se consolide.

Após a cirurgia, os exercícios de movimentação e fortalecimento muscular geralmente começam cedo, muitas vezes nos primeiros dias. Inicialmente, você usará muletas e colocará carga parcial na perna assim que a dor permitir. A carga total só é liberada após a consolidação óssea, verificada por meio de radiografia. Antes de você receber alta, detalharemos o plano de recuperação personalizado para você.

O que esperar

Essas fraturas representam um verdadeiro contratempo, e é útil encará-las com realismo. A maioria delas é tratada mantendo o osso imóvel enquanto cicatriza, com a prótese de joelho permanecendo no lugar. Quando isso é feito corretamente, o osso geralmente se une e a prótese continua funcionando normalmente. Após cirurgias complementares, 89 em cada 100 pessoas com esse tipo de fratura conseguiram a consolidação óssea. Contudo, nem todas as fraturas se consolidam dentro do prazo esperado: alguns ossos demoram mais para unir-se, e um pequeno número nunca chega a se unir. Cerca de 18 em cada 100 pacientes submetidos ao tratamento com placa para essa fratura acabaram não tendo a consolidação óssea, e aproximadamente 24 em cada 100 apresentaram algum tipo de complicação durante o processo.

A cicatrização leva meses, não semanas. Nos casos em que o osso precisa de auxílio adicional para se unir, a consolidação pode ocorrer entre 3 e 8 meses. Você não voltará à normalidade rapidamente; é importante ter essa consciência desde já. Mesmo quando a fratura já estiver consolidada, seus efeitos na qualidade de vida podem persistir por até 12 meses. Muitas pessoas percebem que a perna se cansa mais rápido, que subir escadas exige planejamento e que a confiança no joelho retorna lentamente. Essa é a trajetória típica da recuperação; não é sinal de que algo deu errado.

Existem, porém, aspectos positivos. Quando o osso se une, a prótese de joelho tende a continuar funcionando tão bem quanto antes. Pessoas que sofrem essa fratura não apresentam taxas de sobrevivência da prótese piores do que aquelas que nunca tiveram esse problema. Algumas opções de tratamento também permitem que o paciente apoie peso na perna imediatamente, o que pode reduzir o tempo de internação e acelerar o retorno às atividades cotidianas.

Se o osso for deixado sem intervenção, raramente se consolida sozinho; por isso, a cirurgia costuma ser recomendada precocemente. Os principais riscos a se observar são a falha na consolidação óssea ou a necessidade de novas cirurgias posteriormente. Seu cirurgião explicará como esses dados se aplicam à sua fratura, à qualidade do seu osso e ao seu estado geral de saúde.

Quando procurar ajuda médica

Se você cair ou tropeçar e sentir uma dor aguda logo acima ou abaixo da prótese de joelho, procure atendimento imediatamente. Dirija-se ao pronto-socorro se não conseguir colocar nenhum peso na perna, ou se a perna parecer deformada ou mais curta. Consulte seu médico de família rapidamente caso sinta dor persistente próxima à prótese que não melhora com o repouso, ou dor que o acorda durante a noite. Solicite uma avaliação especializada se o joelho parecer instável, ou se você não confiar que a perna conseguirá sustentá-lo ao ficar de pé. Essas fraturas ocorrem em ossos que se tornaram mais finos e frágeis; por isso, até mesmo um pequeno tropeço pode ser suficiente para causá-las. Caso seja constatada uma fratura, geralmente recomenda-se a cirurgia o quanto antes, pois o osso raramente se consolida sozinho.

Reviewed by AI synthesis (v2) — pending human review · 9 September 2026.

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Evidence & references

This is the clinical evidence summary written for health professionals. It is technical, and it lists the research this page was built from. You do not need to read it to understand your treatment or to make a decision about it.

Anatomy & Pathophysiology

Bony Anatomy

  • The bones of the knee are the distal femur, the proximal tibia, and the patella [1].
  • The medial femoral condyle is larger and projects farther posteriorly and distally than the lateral condyle [4].
  • The lateral femoral condyle projects farther anteriorly and is wider in the medial-lateral direction than the medial femoral condyle [4].
  • The tibial articular surface slopes 7° to 10° in the sagittal plane [4].
  • The posterior slope of the medial tibial plateau averages 10.7° and the lateral plateau averages 7.2° [9].
  • The medial tibial plateau is larger than the lateral plateau and is concave in its frontal and sagittal planes [4].
  • The lateral tibial plateau is smaller, more circular, concave in the frontal plane, and convex in the sagittal plane [4].
  • The patella is the largest sesamoid bone in the body with a mean thickness of 2.5 cm [4, 9].
  • The patellar articular surface contains a vertical central ridge separating the broader lateral facet from the medial facet, and a smaller medial odd facet [4].
  • The fibular head is located a mean of 1.5 cm distal to the joint line, with a range of 6 to 32 mm [9].

Ligaments

  • The anterior cruciate ligament (ACL) prevents anterior translation and rotation of the tibia on the femur [1].
  • The posterior cruciate ligament (PCL) prevents posterior subluxation of the tibia on the femur [1].
  • The medial collateral ligament (MCL) stabilizes the knee to valgus stresses [1].
  • The lateral collateral ligament (LCL) is the main stabilizer against varus stress [1].
  • The ACL is composed of 90% type I collagen and 10% type III collagen [4, 9].
  • The mean length of the ACL is 33 mm and the mean midsubstance width is 11 mm [4, 9].
  • The femoral attachment of the ACL is a semicircular area on the posteromedial aspect of the lateral femoral condyle [4, 9].
  • The tibial attachment of the ACL is a broad, irregular, oval-shaped area between the medial and lateral tibial spinous processes [4, 9].
  • The anteromedial bundle of the ACL is tight in knee flexion and the posterolateral bundle is tight in knee extension [9].
  • The PCL has a mean length of 38 mm and a mean width of 13 mm [9, 17].
  • The PCL femoral footprint is a broad, semicircular attachment on the anterolateral aspect of the medial femoral condyle [9, 17].
  • The PCL tibial insertion is located 10 to 15 mm distal to the joint line on the posterior tibia [9, 17].
  • The anterolateral bundle of the PCL is larger and comprises 85% of the PCL's cross-sectional area [17].
  • The popliteofibular ligament is present in 90% of knees and runs from the popliteus tendon to the posterior fibular head [1].
  • The posterolateral corner (PLC) consists of the fibular collateral ligament, iliotibial band, popliteofibular ligament, biceps femoris, and popliteus tendon [14].

Menisci

  • The menisci are C-shaped fibrocartilaginous disks that provide shock absorption, increase joint congruency, enhance stability, and aid in synovial fluid distribution [1].
  • The medial meniscus is firmly attached to the joint capsule along its entire peripheral edge [1].
  • The lateral meniscus is attached to the anterior and posterior capsule but has a region posterolaterally where it is not firmly attached [1].
  • The medial meniscus has less mobility than the lateral meniscus and is more susceptible to tearing when trapped between the femoral condyle and tibial plateau [1].
  • The lateral meniscus is larger than the medial meniscus and carries a greater share of the lateral compartment pressure [1].
  • The medial meniscus has a mobility of 5 mm and the lateral meniscus has a mobility of 10 mm [9].
  • Vascular supply to the menisci penetrates into 20% to 30% of the peripheral medial meniscus and 10% to 25% of the peripheral lateral meniscus [9].

Vascular and Nerve Anatomy

  • The blood supply to the knee is formed from an anastomosis including the descending geniculate artery, superior and inferior geniculate arteries, middle geniculate artery, and anterior tibial recurrent arteries [4].
  • The middle geniculate artery supplies both the anterior and posterior cruciate ligaments [4].
  • The knee is innervated by branches of the femoral nerve (L2, L3, L4), obturator nerve (L2, L3, L4), and sciatic nerve (L4, L5, S1, S2) [4].
  • The posterior articular branch of the tibial nerve is the largest nerve providing innervation to the intra-articular knee [4].
  • The popliteal artery travels through the adductor hiatus where it is relatively immobile and distally through the fibrous arch deep to the soleus muscle [14].
  • The common peroneal nerve travels along the posterior edge of the biceps femoris and continues distally around the fibular neck [14].

Kinematics

  • The knee is a hinge joint that incorporates both gliding and rolling motions [5, 6].
  • The "screw-home" mechanism involves the tibia externally rotating 5 degrees in the final 15 degrees of extension [5, 6].
  • The greatest range of motion occurs in the sagittal plane at approximately 160° [21].
  • Knee rotation ranges from 45° in external rotation to 30° in internal rotation [21].
  • In the frontal plane, the range of motion in both abduction and adduction reaches a maximum of 10° [21].
  • During walking, knee range of motion reaches approximately 70° in the sagittal plane, 15° in the frontal plane, and 10° in the transverse plane [21].
  • The normal instant center of the knee joint follows a semicircular path related to the tibiofemoral surface and ligaments [21].
  • Rupture of the cruciate ligaments or disruption of the tibiofemoral surface causes a major change in the path of the instant center, leading to articular dysfunction [21].
  • In full extension, the knee slightly hyperextends with slight tibial external rotation while collateral and cruciate ligaments tighten to lock the knee [22].
  • The popliteus muscle initiates flexion by pulling the lateral femoral condyle backward while the medial femoral condyle slides forward, resulting in tibial internal rotation [22].

Periprosthetic Fracture Pathophysiology

  • The incidence of periprosthetic fracture of the distal femur in total knee arthroplasty is 0.3% to 2.5% [31].
  • The incidence of periprosthetic tibial fracture in primary total knee arthroplasty is 0.7% or less [31].
  • Anterior femoral notching during femoral preparation weakens the anterior femur at the bone-component interface [31].
  • Notching decreases the fracture resistance of the distal femur but does not necessarily equate to a higher risk of supracondylar femur fracture [31].
  • Risk factors for periprosthetic distal femur fracture include rheumatoid arthritis, neurologic disorders, chronic steroid therapy, osteopenia or osteoporosis, and osteolysis with bone loss [31].
  • Risk factors for periprosthetic tibial fracture include insertion of a long-stem component, a loose tibial component, periprosthetic osteolysis, malalignment of components, component removal during revision, and tibial tubercle osteotomy [31].
  • The fracture line in periprosthetic fractures may be obscured by a metallic component on plain radiographs [31].

Investigations

Plain Radiography

  • Plain radiographs are appropriate initial imaging studies for most knee conditions, allowing assessment of traumatic injury, arthritis, patellofemoral alignment, osteochondral injury, bone neoplasm, and surgical implants [3].
  • Imaging studies should include at least two perpendicular views: AP and lateral [3].
  • Weight-bearing AP (extension) views are used to assess cartilage loss from the distal femur and tibial plateau [3].
  • Weight-bearing PA (Rosenberg; flexion) views are used to assess cartilage loss from the posterior femur and tibial plateau [3].
  • Patellofemoral views are used to assess patellofemoral alignment, patellar and trochlear morphology, osteochondral injury, and patellofemoral arthritis [3].
  • Notch views are used to assess posterior femoral cartilage, notch width, and osteophytes [3].
  • Non-weight-bearing radiographs may identify acute injury without the risk of fracture displacement [3].
  • Radiography may identify subchondral sclerosis, joint space narrowing, subchondral cysts, osteophytes, and joint subluxation in osteoarthritis [3].
  • Radiography may identify linear radiolucency or radiodensity in stress fractures, most commonly in the proximal medial tibia [3].
  • Radiography may identify a mixed sclerotic pattern with a subchondral, epiphyseal, or metaphyseal location in osteonecrosis [3].
  • Supine AP knee radiographs do not adequately estimate the joint space width needed to estimate the degree of osteoarthritis progression [27].
  • A 45° standing flexion view was introduced to better evaluate joint space due to inaccuracies in plain frontal radiographs [27].
  • The fixed flexion view (FFV) technique uses a 10° caudal irradiation angle and fixed limb position for improved reproducibility and joint space evaluation [27].
  • The Lyon Schuss view (LSV) requires fluoroscopic adjustment of the irradiation angle relative to the medial tibial plateau for more accurate joint space width measurement but involves higher radiation exposure and complex positioning [27].
  • Goniometer readings of long limb alignment or measured on an FFV correlate well with angles measured on long limb radiographs, providing an alternative if long limb radiographs are not available [27].
  • The Kellgren-Lawrence (KL) classification grades osteoarthritis severity from 0 to 4 based on AP knee radiograph features including osteophytes and joint space narrowing [23].
  • Knee arthroplasty is recommended when KL Grade 4 findings are present [23].

Computed Tomography

  • CT provides enhanced bone detail through a three-dimensional study performed with ionizing radiation [3].
  • CT imaging in axial, sagittal, and coronal planes helps visualize fracture lines, displacement, osteolytic lesions around joint arthroplasty, and cortical disruption in infection or neoplasia [3].
  • Three-dimensional CT reconstructions may help with preoperative planning for complex intra-articular fractures, multiplanar osteotomy for limb malalignment, and reconstitution of bone loss in joint arthroplasty [3].
  • Axial plane CT imaging of the knee can help assess the rotational alignment of components of a total knee arthroplasty in cases of patellar maltracking [3].
  • Three-dimensional CT with remodeling is used for preoperative planning for reconstruction associated with dysplasia, post-trauma planning, and complex total knee arthroplasty planning [23].

Magnetic Resonance Imaging

  • MRI may help assess overall limb alignment and further delineate intra-articular and extra-articular soft tissues, including cartilage, menisci, ligaments, tendons, muscles, and nerve and vascular structures [3].
  • MRI findings of edema, intra-articular fluid, disruption of ligament fibers, and atypical ligament contour may suggest cruciate ligament injury [3].
  • MRI can identify patterns of meniscal injury by location, pattern (horizontal, longitudinal, radial, complex), and displacement [3].
  • MRI may identify the degree of articular cartilage injury, associated bone marrow edema, and lesion location [3].
  • MRI may identify edema, avulsion, or discontinuity for extra-articular ligaments such as the MCL/LCL or associated posteromedial and posterolateral ligamentous complexes [3].
  • MRI may be used to assess the continuity of the quadriceps or patellar tendon [3].
  • MRI may be used to assess neurovascular structures, including the margin of resection for a neoplasm, vascular malformation, or location of nerves relative to popliteal cysts [3].
  • MRI is the most useful study for differentiating osteonecrosis from other conditions such as osteochondritis dissecans, transient osteoporosis, bone bruises, or occult fractures [29].
  • A serpentine lesion within a well-demarcated border is a specific finding on MRI for osteonecrosis [29].
  • MRI is not indicated if the joint space is significantly narrowed on radiograph in the arthritic patient population [23].
  • MRI is used when osteonecrosis is suspected in the arthritic patient population [23].

Nuclear Medicine

  • Increased radionuclide activity in bone may be a normal postoperative finding for up to 6 to 12 months after a fracture repair or arthroplasty [3].
  • Technetium-99 (Tc-99) may help identify infection, neoplasia, occult fracture, bone healing, active phases of heterotopic ossification, implant loosening, or failure of osseointegration [3].
  • Gallium-67 (Ga-67) may help differentiate between aseptic and septic prosthetic loosening, requiring 24 to 72 hours for a complete study [3].

General Assessment

  • Radiographic studies help confirm the clinical diagnosis of a joint disorder determined using the patient’s history and physical examination [3].
  • Physical examination along with radiographic or advanced imaging findings must be used concomitantly to determine the source of symptoms and appropriate surgical intervention [7].
  • Assessment of the joint must combine physical examination along with radiographic (including full-length alignment views) and MRI findings for cartilage injury [30].

References

[1] A Lange Medical Book Current Diagnosis Treatment In Orthopedics Fifth Edition. 3Sports Medicine > Image KNEE INJURIES.

[3] Aaos Comprehensive Orthopaedic Review 3. Radiographic Evaluation and Surgical Anatomy of the Knee > I. Radiographic Evaluation.

[4] Aaos Comprehensive Orthopaedic Review 3. Anatomy and Biomechanics of the Knee > I. Anatomy.

[5] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > SECTION 1 KNEE > ANATOMY (FIG. 4.1).

[6] Miller S Review Of Orthopaedics. SECTION 1 KNEE > ANATOMY (FIG. 4.1).

[7] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Knee Arthroscopy and Preservation, Knee Reconstruction > Introduction.

[9] Aaos Comprehensive Orthopaedic Review 3. Radiographic Evaluation and Surgical Anatomy of the Knee > II. Surgical Anatomy of the Knee.

[14] Aaos Comprehensive Orthopaedic Review 3. Knee Dislocations and Patellar Fractures* > I. Knee Dislocations.

[17] Rockwood And Green S Fractures In Adults. 59: Patellar Fractures and Dislocations and Extensor Mechanism Injuries > Posterior Knee Anatomy.

[21] Aaos Comprehensive Orthopaedic Review 3. Biomechanics and Wear in Joint Arthroplasty > III. The Knee Joint.

[22] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Knee Anatomy > Knee Kinematics.

[23] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > SECTION 11 KNEE ARTHRITIS ASSESSMENT.

[27] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Knee Anatomy > Imaging (Radiograph, MRI, CT Scan, Dynamic Versus Static) > Radiograph.

[29] Aaos Comprehensive Orthopaedic Review 3. General Evaluation of the Knee Patient > III. Osteonecrosis.

[30] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Knee Arthroscopy and Preservation, Knee Reconstruction > Summary.

[31] Aaos Comprehensive Orthopaedic Review 3. Periprosthetic Fractures Associated With Total Hip and Knee Arthroplasty > II. Total Knee Arthroplasty.

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k. Sui Generis Database Rights means rights other than copyright resulting from Directive 96/9/EC of the European Parliament and of the Council of 11 March 1996 on the legal protection of databases, as amended and/or succeeded, as well as other essentially equivalent rights anywhere in the world.

l. You means the individual or entity exercising the Licensed Rights under this Public License. Your has a corresponding meaning.

Section 2 -- Scope.

a. License grant.

1. Subject to the terms and conditions of this Public License, the Licensor hereby grants You a worldwide, royalty-free, non-sublicensable, non-exclusive, irrevocable license to exercise the Licensed Rights in the Licensed Material to:

a. reproduce and Share the Licensed Material, in whole or in part, for NonCommercial purposes only; and

b. produce, reproduce, and Share Adapted Material for NonCommercial purposes only.

2. Exceptions and Limitations. For the avoidance of doubt, where Exceptions and Limitations apply to Your use, this Public License does not apply, and You do not need to comply with its terms and conditions.

3. Term. The term of this Public License is specified in Section 6(a).

4. Media and formats; technical modifications allowed. The Licensor authorizes You to exercise the Licensed Rights in all media and formats whether now known or hereafter created, and to make technical modifications necessary to do so. The Licensor waives and/or agrees not to assert any right or authority to forbid You from making technical modifications necessary to exercise the Licensed Rights, including technical modifications necessary to circumvent Effective Technological Measures. For purposes of this Public License, simply making modifications authorized by this Section 2(a) (4) never produces Adapted Material.

5. Downstream recipients.

a. Offer from the Licensor -- Licensed Material. Every recipient of the Licensed Material automatically receives an offer from the Licensor to exercise the Licensed Rights under the terms and conditions of this Public License.

b. No downstream restrictions. You may not offer or impose any additional or different terms or conditions on, or apply any Effective Technological Measures to, the Licensed Material if doing so restricts exercise of the Licensed Rights by any recipient of the Licensed Material.

6. No endorsement. Nothing in this Public License constitutes or may be construed as permission to assert or imply that You are, or that Your use of the Licensed Material is, connected with, or sponsored, endorsed, or granted official status by, the Licensor or others designated to receive attribution as provided in Section 3(a)(1)(A)(i).

b. Other rights.

1. Moral rights, such as the right of integrity, are not licensed under this Public License, nor are publicity, privacy, and/or other similar personality rights; however, to the extent possible, the Licensor waives and/or agrees not to assert any such rights held by the Licensor to the limited extent necessary to allow You to exercise the Licensed Rights, but not otherwise.

2. Patent and trademark rights are not licensed under this Public License.

3. To the extent possible, the Licensor waives any right to collect royalties from You for the exercise of the Licensed Rights, whether directly or through a collecting society under any voluntary or waivable statutory or compulsory licensing scheme. In all other cases the Licensor expressly reserves any right to collect such royalties, including when the Licensed Material is used other than for NonCommercial purposes.

Section 3 -- License Conditions.

Your exercise of the Licensed Rights is expressly made subject to the following conditions.

a. Attribution.

1. If You Share the Licensed Material (including in modified form), You must:

a. retain the following if it is supplied by the Licensor with the Licensed Material:

i. identification of the creator(s) of the Licensed Material and any others designated to receive attribution, in any reasonable manner requested by the Licensor (including by pseudonym if designated);

ii. a copyright notice;

iii. a notice that refers to this Public License;

iv. a notice that refers to the disclaimer of warranties;

v. a URI or hyperlink to the Licensed Material to the extent reasonably practicable;

b. indicate if You modified the Licensed Material and retain an indication of any previous modifications; and

c. indicate the Licensed Material is licensed under this Public License, and include the text of, or the URI or hyperlink to, this Public License.

2. You may satisfy the conditions in Section 3(a)(1) in any reasonable manner based on the medium, means, and context in which You Share the Licensed Material. For example, it may be reasonable to satisfy the conditions by providing a URI or hyperlink to a resource that includes the required information.

3. If requested by the Licensor, You must remove any of the information required by Section 3(a)(1)(A) to the extent reasonably practicable.

4. If You Share Adapted Material You produce, the Adapter's License You apply must not prevent recipients of the Adapted Material from complying with this Public License.

Section 4 -- Sui Generis Database Rights.

Where the Licensed Rights include Sui Generis Database Rights that apply to Your use of the Licensed Material:

a. for the avoidance of doubt, Section 2(a)(1) grants You the right to extract, reuse, reproduce, and Share all or a substantial portion of the contents of the database for NonCommercial purposes only;

b. if You include all or a substantial portion of the database contents in a database in which You have Sui Generis Database Rights, then the database in which You have Sui Generis Database Rights (but not its individual contents) is Adapted Material; and

c. You must comply with the conditions in Section 3(a) if You Share all or a substantial portion of the contents of the database.

For the avoidance of doubt, this Section 4 supplements and does not replace Your obligations under this Public License where the Licensed Rights include other Copyright and Similar Rights.

Section 5 -- Disclaimer of Warranties and Limitation of Liability.

a. UNLESS OTHERWISE SEPARATELY UNDERTAKEN BY THE LICENSOR, TO THE EXTENT POSSIBLE, THE LICENSOR OFFERS THE LICENSED MATERIAL AS-IS AND AS-AVAILABLE, AND MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND CONCERNING THE LICENSED MATERIAL, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHER. THIS INCLUDES, WITHOUT LIMITATION, WARRANTIES OF TITLE, MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT, ABSENCE OF LATENT OR OTHER DEFECTS, ACCURACY, OR THE PRESENCE OR ABSENCE OF ERRORS, WHETHER OR NOT KNOWN OR DISCOVERABLE. WHERE DISCLAIMERS OF WARRANTIES ARE NOT ALLOWED IN FULL OR IN PART, THIS DISCLAIMER MAY NOT APPLY TO YOU.

b. TO THE EXTENT POSSIBLE, IN NO EVENT WILL THE LICENSOR BE LIABLE TO YOU ON ANY LEGAL THEORY (INCLUDING, WITHOUT LIMITATION, NEGLIGENCE) OR OTHERWISE FOR ANY DIRECT, SPECIAL, INDIRECT, INCIDENTAL, CONSEQUENTIAL, PUNITIVE, EXEMPLARY, OR OTHER LOSSES, COSTS, EXPENSES, OR DAMAGES ARISING OUT OF THIS PUBLIC LICENSE OR USE OF THE LICENSED MATERIAL, EVEN IF THE LICENSOR HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH LOSSES, COSTS, EXPENSES, OR DAMAGES. WHERE A LIMITATION OF LIABILITY IS NOT ALLOWED IN FULL OR IN PART, THIS LIMITATION MAY NOT APPLY TO YOU.

c. The disclaimer of warranties and limitation of liability provided above shall be interpreted in a manner that, to the extent possible, most closely approximates an absolute disclaimer and waiver of all liability.

Section 6 -- Term and Termination.

a. This Public License applies for the term of the Copyright and Similar Rights licensed here. However, if You fail to comply with this Public License, then Your rights under this Public License terminate automatically.

b. Where Your right to use the Licensed Material has terminated under Section 6(a), it reinstates:

1. automatically as of the date the violation is cured, provided it is cured within 30 days of Your discovery of the violation; or

2. upon express reinstatement by the Licensor.

For the avoidance of doubt, this Section 6(b) does not affect any right the Licensor may have to seek remedies for Your violations of this Public License.

c. For the avoidance of doubt, the Licensor may also offer the Licensed Material under separate terms or conditions or stop distributing the Licensed Material at any time; however, doing so will not terminate this Public License.

d. Sections 1, 5, 6, 7, and 8 survive termination of this Public License.

Section 7 -- Other Terms and Conditions.

a. The Licensor shall not be bound by any additional or different terms or conditions communicated by You unless expressly agreed.

b. Any arrangements, understandings, or agreements regarding the Licensed Material not stated herein are separate from and independent of the terms and conditions of this Public License.

Section 8 -- Interpretation.

a. For the avoidance of doubt, this Public License does not, and shall not be interpreted to, reduce, limit, restrict, or impose conditions on any use of the Licensed Material that could lawfully be made without permission under this Public License.

b. To the extent possible, if any provision of this Public License is deemed unenforceable, it shall be automatically reformed to the minimum extent necessary to make it enforceable. If the provision cannot be reformed, it shall be severed from this Public License without affecting the enforceability of the remaining terms and conditions.

c. No term or condition of this Public License will be waived and no failure to comply consented to unless expressly agreed to by the Licensor.

d. Nothing in this Public License constitutes or may be interpreted as a limitation upon, or waiver of, any privileges and immunities that apply to the Licensor or You, including from the legal processes of any jurisdiction or authority.

Creative Commons is not a party to its public licenses. Notwithstanding, Creative Commons may elect to apply one of its public licenses to material it publishes and in those instances will be considered the “Licensor.” The text of the Creative Commons public licenses is dedicated to the public domain under the CC0 Public Domain Dedication. Except for the limited purpose of indicating that material is shared under a Creative Commons public license or as otherwise permitted by the Creative Commons policies published at creativecommons.org/policies, Creative Commons does not authorize the use of the trademark "Creative Commons" or any other trademark or logo of Creative Commons without its prior written consent including, without limitation, in connection with any unauthorized modifications to any of its public licenses or any other arrangements, understandings, or agreements concerning use of licensed material. For the avoidance of doubt, this paragraph does not form part of the public licenses.

Creative Commons may be contacted at creativecommons.org.