Atualmente, os bons resultados na lesão do ligamento cruzado posterior por avulsão óssea na tíbia associam-se ao tratamento cirúrgico e precoce. A técnica convencional é a fixação com parafuso pela via de acesso posterior do joelho, com abordagem direta das estruturas vasculares e nervosas da região. Neste estudo experimental em 20 joelhos de cadáveres, buscamos apresentar uma alternativa com amarrilho por via artroscópica, comparando-o com a técnica convencional, através da inspeção direta e de testes biomecânicos. Houve falha na fixação de apenas um exemplar de cada método e medidas de deslocamento tibial posterior (p=0,23) e rigidez média (p=0,28) sem diferenças significativas entre as duas técnicas. Concluímos ser o amarrilho artroscópico viável e uma alternativa no tratamento desta lesão. / Nowadays, good results on the management of posterior cruciate ligament bony avulsion of the tibia are associated with early surgical repair. The usual method of treatment is the open posterior approach with screw fixation, wich requires popliteal neurovascular bundle direct manipulation. This study presents a new arthroscopic suture and compares it with the conventional technique, using biomechanical tests and direct inspection in cadaveric specimens (20 knees). On both methods there was a fixation fail in one knee. The analisys of tibial posterior displacement (p=0,23) and stiffness (p=0,20) were similar for the two methods. The Arthroscopic suture presented is an effective reattachment method for this fracture pattern.

OBJETIVO: Avaliar o padrão de degeneração histológica do ligamento cruzado posterior (LCP) em pacientes com artrose submetidos à artroplastia total de joelho com prótese com substituição do ligamento cruzado posterior (LCP). A degeneração histológica foi classificada em leve, moderada e grave. Os achados histológicos foram correlacionados com dados clínicos, radiográficos e do transoperatório (presença ou ausência do ligamento cruzado anterior) com a finalidade de aferir se estes parâmetros seriam capazes de predizer o grau de degeneração histológica do LCP em pacientes com gonartrose. MÉTODOS: foram avaliados 89 ligamentos cruzados posterior de 85 pacientes com idade média de 69,79 anos, sendo 69 do sexo feminino, 16 do masculino. O LCP foi corado em hematoxilina-eosina e Tricrômio de Gomori e classificado quanto ao comprometimento histológico em leve, moderado e grave. A degeneração histológica foi correlacionada aos parâmetros idade, artrose radiográfica classificada por Ahlbäck (grau I ao V), eixo radiográfico tíbio-femoral (varo, neutro e valgo), e estado do ligamento cruzado anterior (LCA), presença ou ausência.Os achados histológicos de hipercelularidade, infiltração linfocitária crônica, proliferação vascular; presença de cistos; clones de condrócitos; degenerações colágena, fibrinóide, cartilaginosa ,gordurosa e mucoide foram correlacionados com o grau de degeneração do LCP e ao estado de conservação do LCA. RESULTADO: Não foram identificadas relações entre o grau de degeneração histológica do LCP e faixa etária (abaixo ou acima de 70 anos), sexo, classificação radiográfica de Ahlbäck e presença ou ausência do LCA. Os achados histológicos de degeneração fibrinóide, proliferação vascular e presença de cistos estiveram estatisticamente relacionados à degeneração histológica grave do LCP. CONCLUSÃO: Os parâmetros clínicos e radiográficos não foram capazes de predizer o grau de degeneração histológica do LCP .Os achados histológicos de degeneração fibrinóide, proliferação vascular e presença de cistos caracterizaram a degeneração histológica grave do LCP / OBJECTIVE: Evaluate the histologic degeneration pattern of the posterior cruciate ligament (PCL) in osteoarthrosis patients submitted to total knee replacement with a cruciate substituting prosthesis. The histologic degeneration was classified in mild, moderate and severe. The histologic pattern was related to clinical, per-operatory (presence or absence of anterior cruciate ligament) and radiographic parameters with the aim to settle if these parameters would be reliable to predict the PCL degeneration grade. METHODS: 89 PCLs from 85 patients, 16 men, 69 women, mean age 69, 79 years old. PCL was stained with hematoxylin and eosin and trichromium of Gomori. The PCL histologic degeneration was graded from normal-minimum to severe. The histologic PCL degeneration pattern was related to age, radiographic arthrosis classification (Ahlbäck - grades I to V), knee radiographic axis (varus, neutral, valgus) and to the ACL status (presence or absence).The histologic findings of hipercellularity, chronic lymphocit infiltration, neoangiogenesis, cysts, collagen degeneration (deg), fibrinoid deg, mucoid deg., cartilaginous, deg., fat deg. and condrocyte clones were related to the grade of PCL degeneration and to ACL status. RESULTS: There was no correlation of histologic degeneration to sex or age (above or below 70 years), arthrosis radiographic classification (Ahlbäck) and presence or absence of ACL. The histological findings of fibrinoid degeneration, vascular proliferation and cysts were statistically related to severe histologic LCP degeneration. CONCLUSION: The parameters studied were not capable of predicting the grade of LCP degeneration. The histological findings of fibrinoid degeneration, vascular proliferation and cysts were characteristic of severe PCL histologic degeneration

INTRODUÇÃO: A instabilidade multiligamentar do joelho, normalmente, é provocada por um trauma que determina sua luxação, um evento pouco frequente, mas, que pode trazer sequelas devastadoras. Mesmo com o tratamento cirúrgico preconizado é alto o índice de complicações. A mobilização precoce no pósoperatório provoca afrouxamento dos ligamentos reconstruídos, o que leva à instabilidade residual. A imobilização melhora a estabilidade, mas provoca dor e rigidez. Este trabalho tem o objetivo de avaliar se o uso do fixador externo articulado proporciona melhora na mobilidade, estabilidade e na função subjetiva de pacientes submetidos à reconstrução ligamentar. MÉTODOS: Neste ensaio clínico randomizado com grupos paralelos, 33 pacientes do ambulatório do Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da Universidade de São Paulo com mais que 3 semanas de lesão dos ligamentos cruzados anterior e posterior associado à lesão de ligamento colateral fibular e/ ou ligamento colateral tibial foram submetidos à cirurgia de reconstrução multiligamentar, após alocação cega aleatória ao grupo 0 - controle (18 pacientes), com órtese rígida ou ao grupo 1 - fixador externo articulado por 6 semanas (15 pacientes), no período entre novembro de 2010 e novembro de 2013. Após seguimento mínimo de um ano de pós-operatório, a estabilidade dos ligamentos reconstruídos foi avaliada ao exame físico, foram mensurados os déficits de extensão e de flexão residual em relação ao joelho contralateral não acometido e foi aplicado o questionário específico para sintomas do joelho de Lysholm. RESULTADOS: Não houve diferença na avaliação da estabilidade articular nem na extensão entre os grupos. No grupo 1, o déficit de flexão passiva foi menor (4,8º +- 5,4º contra 18,2 +- 14,8º, p < 0,05) com mais pacientes, obtendo déficit de flexão considerado normal, de até 5º (64% contra 18%, p < 0,05) e com classificação excelente ou boa no questionário de Lysholm (73% contra 35%, p < 0,05). CONCLUSÕES: Comparado ao protocolo de reabilitação com órtese rígida removível, o uso do fixador externo articulado no tratamento cirúrgico das lesões multiligamentares do joelho proporciona os mesmos resultados de estabilidade ligamentar, aumenta a amplitude de movimento final, com manutenção da extensão e redução do déficit de flexão e proporciona melhores resultados funcionais / INTRODUCTION: Multiligament knee instability is normally caused by a trauma which results in its dislocation, an infrequent event, but one which can have devastating aftereffects. Even with the recommended surgical treatment the rate of complications is high. Early post-operative mobilization provokes loosening of the reconstructed ligaments, which leads to residual instability. Immobilization improves the stability, but causes pain and stiffness. This study aims to assess whether the use of an articulated external fixator provides improvements in the mobility, stability and the subjective function of the patients submitted to ligament reconstruction. METHODS: In this randomized clinical trial with parallel groups, 33 patients of the outpatient clinic of the Institute of Orthopaedics and Traumatology of the Hospital das Clínicas of the University of Sao Paulo with more than 3 weeks of injury to the anterior cruciate ligaments and the posterior cruciate ligaments associated with injury to the fibular collateral ligament and/or medial collateral ligament, were submitted to multiligament reconstruction surgery, after blind random allocation to either: Group 0 - control (18 patients), with rigid bracing, or to Group 1 - articulated external fixator for 6 weeks (15 patients), in the period from November, 2010 to November 2013. The stability of the reconstructed ligaments were assessed after 1 year postoperatively by physical examination, the deficit of residual extension and flexion was measured in relation to the unaffected contralateral knee and the Lysholm knee scoring scale questionnaire was applied. RESULTS: There was no difference in the assessment of joint stability or of the extension between the groups. In group 1 the passive flexion deficit was less (4.8º +- 5.4º versus 18.2 +- 14.8º, p<0.05) with more patients obtaining a flexion deficit considered normal, or up to 5º (64% versus 18%, p<0.05) and with excellent or good classification in the Lysholm knee scoring scale questionnaire (73% versus 35%, p<0.05). CONCLUSIONS: Compared to the rehabilitation protocol with removable rigid bracing, the use of an articulated external fixator in the treatment of multiligament knee injuries provides equal results for ligament stability, increases the amplitude of the Range of Motion, maintains the extension and reduces the flexion deficit, and provides better functional result

La luxation du genou, bien que très rare, demeure une blessure dévastatrice car elle entraîne de multiples complications en raison de la nature complexe du traumatisme associé à cette lésion. La luxation peut résulter d'un traumatisme à haute ou basse énergie. Les blessures sévères aux ligaments et aux structures associées donnent à la luxation du genou un potentiel élevé d'atteinte fonctionnelle. Le traitement conservateur, qui était considéré comme acceptable auparavant, est maintenant réservé à un très faible pourcentage de patients. La reconstruction chirurgicale est maintenant préconisée dans la plupart des cas, mais de nombreuses options existent et le traitement chirurgical optimal à préconiser reste controversé. Certains chirurgiens recommandent la reconstruction complète de tous les ligaments endommagés le plus tôt possible, tandis que d'autres, craignant l’établissement d’arthrofibrose, limitent l'intervention chirurgicale immédiate à la reconstruction du ligament croisé postérieur et de l'angle postéro-externe. En raison des multiples structures endommagées lors d’une luxation du genou, les chirurgiens utilisent couramment la combinaison des autogreffes et des allogreffes pour compléter la reconstruction ligamentaire. Les complications associées au prélèvement de la greffe, l'allongement de la greffe, l’affaiblissement précoce du greffon ainsi que les risques de transmission de maladies ont poussé les chirurgiens à rechercher différentes options d’intervention. L'utilisation de matériaux synthétiques pour le remplacement du ligament lésé a été proposée dans les années ´80. Après une première vague d'enthousiasme, les résultats décevants à long terme et les taux élevés d'échec ont diminué sa popularité. Depuis lors, une nouvelle génération de ligaments artificiels a vu le jour et parmi eux, le Ligament Advanced Reinforced System (LARS) a montré des résultats prometteurs. Il a été utilisé récemment dans les reconstructions isolées du ligament croisé antérieur et du ligament croisé postérieur pour lesquelles il a montré de bons résultats à court et moyen termes. Le but de cette étude rétrospective était d'évaluer la fonction et la stabilité du genou après la luxation aiguë suivant la reconstruction des ligaments croisés avec le ligament artificiel de type LARS. Cette étude a évalué 71 patients présentant une luxation du genou et qui ont subi une chirurgie de reconstruction du ligament croisé antérieur et du ligament croisé postérieur à l'aide du ligament LARS. Suite à la chirurgie le même protocole intensif de réadaptation a été suivi pour tous les patients, où la mise en charge progressive était permise après une période d’environ 6 semaines pendant laquelle la force musculaire et la stabilité dynamique se rétablissaient. Les outils d’évaluation utilisés étaient le score Lysholm, le formulaire de «l’International Knee Documentation Committee», le «Short Form-36», les tests cliniques de stabilité du genou, l'amplitude de mouvement articulaire à l’aide d’un goniomètre et la radiographie en stress Telos à 30° et 90° de flexion du genou. Le même protocole d’évaluation a été appliqué au genou controlatéral pour des fins de comparaison. Les résultats subjectifs et objectifs de cette étude sont satisfaisants et suggèrent que la réparation et la reconstruction combinées avec ligaments LARS est une alternative valable pour le traitement des luxations aiguës du genou. Ces résultats démontrent que ces interventions produisent des effets durables en termes d’amélioration de la fonction et révèlent la durabilité à long terme des ligaments artificiels LARS. Les patients sont à la fois plus autonomes et plus satisfaits avec le temps, même si la luxation du genou est considérée comme une catastrophe au moment où elle se produit. Des études prospectives randomisées sont maintenant nécessaires afin de comparer la sélection de la greffe et le délai de reconstruction chirurgicale. / Knee dislocation, although very rare, remains a devastating injury with many complications because of the complex nature of this trauma. This uncommon injury can result from either a high or low energy trauma. The severe damage to the knee’s ligaments and associated structures render this injury at high potential for functional impairment. Non operative treatment which was once deemed acceptable, is now reserved for very low demand patients. Surgical reconstruction is now the standard of care for most patients, however many options exist but the optimal surgical treatment remains controversial. Some surgeons advocate early complete reconstruction of all damaged ligaments, whereas others who fear arthrofibrosis, limit the immediate surgery to reconstruction of the posterior cruciate ligament and the posterolateral corner. Because of the multiple structures damaged by knee dislocations, surgeons have been successfully using combinations of autografts and allografts for complete knee ligament reconstruction. Complications associated with graft harvesting, graft elongation and early weakness as well as risks for disease transmission has pushed surgeons to look for different options. The use of synthetic material for ligament replacement was proposed in the 1980’s. After an initial wave of enthusiasm, poor long term results and high rates of failure diminished its popularity. Since then, a new generation of artificial ligaments has emerged, the Ligament Advanced Reinforced System (LARS) has shown promising results. It recently has been used in isolated anterior cruciate ligament and posterior cruciate ligament reconstruction and has shown good short to medium term results. The purpose of this retrospective study was to evaluate the knee function and stability after acute knee dislocation reconstructed with LARS artificial ligaments. This study assessed the results of 71 patients with knee dislocations who underwent acute combined repair and reconstruction of anterior cruciate ligament and posterior cruciate ligament using LARS artificial ligaments. After the surgery all patients followed the same intensive rehabilitation protocol. Progressive weight bearing was permitted over 6 weeks as muscle strength and dynamic stability were regained. The outcome measures used were the Lysholm score, the International Knee Documentation Committee form, the Short Form-36, clinical knee stability testing, a goniometer to mesure the range of motion and Telos stress radiography at 30° and 90° of knee flexion. The non-operated knee of the patient was used as a baseline for the operated knee. The subjective and objective findings from this study are satisfactory and suggest that acute combined repair and reconstruction with LARS ligaments is a valid alternative for treating acute knee dislocations. These findings demonstrate sustained results in terms of function and revealed durability of LARS artificial ligaments at long-term. Patients seem to get more autonomous and satisfied with time even though acute knee dislocation is seen as a catastrophe when it happens. Randomised, prospective trials are now needed to compare graft selection and timing of the surgical reconstruction.

INTRODUÇÃO: A instabilidade multiligamentar do joelho, normalmente, é provocada por um trauma que determina sua luxação, um evento pouco frequente, mas, que pode trazer sequelas devastadoras. Mesmo com o tratamento cirúrgico preconizado é alto o índice de complicações. A mobilização precoce no pósoperatório provoca afrouxamento dos ligamentos reconstruídos, o que leva à instabilidade residual. A imobilização melhora a estabilidade, mas provoca dor e rigidez. Este trabalho tem o objetivo de avaliar se o uso do fixador externo articulado proporciona melhora na mobilidade, estabilidade e na função subjetiva de pacientes submetidos à reconstrução ligamentar. MÉTODOS: Neste ensaio clínico randomizado com grupos paralelos, 33 pacientes do ambulatório do Instituto de Ortopedia e Traumatologia do Hospital das Clínicas da Universidade de São Paulo com mais que 3 semanas de lesão dos ligamentos cruzados anterior e posterior associado à lesão de ligamento colateral fibular e/ ou ligamento colateral tibial foram submetidos à cirurgia de reconstrução multiligamentar, após alocação cega aleatória ao grupo 0 - controle (18 pacientes), com órtese rígida ou ao grupo 1 - fixador externo articulado por 6 semanas (15 pacientes), no período entre novembro de 2010 e novembro de 2013. Após seguimento mínimo de um ano de pós-operatório, a estabilidade dos ligamentos reconstruídos foi avaliada ao exame físico, foram mensurados os déficits de extensão e de flexão residual em relação ao joelho contralateral não acometido e foi aplicado o questionário específico para sintomas do joelho de Lysholm. RESULTADOS: Não houve diferença na avaliação da estabilidade articular nem na extensão entre os grupos. No grupo 1, o déficit de flexão passiva foi menor (4,8º +- 5,4º contra 18,2 +- 14,8º, p < 0,05) com mais pacientes, obtendo déficit de flexão considerado normal, de até 5º (64% contra 18%, p < 0,05) e com classificação excelente ou boa no questionário de Lysholm (73% contra 35%, p < 0,05). CONCLUSÕES: Comparado ao protocolo de reabilitação com órtese rígida removível, o uso do fixador externo articulado no tratamento cirúrgico das lesões multiligamentares do joelho proporciona os mesmos resultados de estabilidade ligamentar, aumenta a amplitude de movimento final, com manutenção da extensão e redução do déficit de flexão e proporciona melhores resultados funcionais / INTRODUCTION: Multiligament knee instability is normally caused by a trauma which results in its dislocation, an infrequent event, but one which can have devastating aftereffects. Even with the recommended surgical treatment the rate of complications is high. Early post-operative mobilization provokes loosening of the reconstructed ligaments, which leads to residual instability. Immobilization improves the stability, but causes pain and stiffness. This study aims to assess whether the use of an articulated external fixator provides improvements in the mobility, stability and the subjective function of the patients submitted to ligament reconstruction. METHODS: In this randomized clinical trial with parallel groups, 33 patients of the outpatient clinic of the Institute of Orthopaedics and Traumatology of the Hospital das Clínicas of the University of Sao Paulo with more than 3 weeks of injury to the anterior cruciate ligaments and the posterior cruciate ligaments associated with injury to the fibular collateral ligament and/or medial collateral ligament, were submitted to multiligament reconstruction surgery, after blind random allocation to either: Group 0 - control (18 patients), with rigid bracing, or to Group 1 - articulated external fixator for 6 weeks (15 patients), in the period from November, 2010 to November 2013. The stability of the reconstructed ligaments were assessed after 1 year postoperatively by physical examination, the deficit of residual extension and flexion was measured in relation to the unaffected contralateral knee and the Lysholm knee scoring scale questionnaire was applied. RESULTS: There was no difference in the assessment of joint stability or of the extension between the groups. In group 1 the passive flexion deficit was less (4.8º +- 5.4º versus 18.2 +- 14.8º, p<0.05) with more patients obtaining a flexion deficit considered normal, or up to 5º (64% versus 18%, p<0.05) and with excellent or good classification in the Lysholm knee scoring scale questionnaire (73% versus 35%, p<0.05). CONCLUSIONS: Compared to the rehabilitation protocol with removable rigid bracing, the use of an articulated external fixator in the treatment of multiligament knee injuries provides equal results for ligament stability, increases the amplitude of the Range of Motion, maintains the extension and reduces the flexion deficit, and provides better functional result

OBJETIVO: Avaliar o padrão de degeneração histológica do ligamento cruzado posterior (LCP) em pacientes com artrose submetidos à artroplastia total de joelho com prótese com substituição do ligamento cruzado posterior (LCP). A degeneração histológica foi classificada em leve, moderada e grave. Os achados histológicos foram correlacionados com dados clínicos, radiográficos e do transoperatório (presença ou ausência do ligamento cruzado anterior) com a finalidade de aferir se estes parâmetros seriam capazes de predizer o grau de degeneração histológica do LCP em pacientes com gonartrose. MÉTODOS: foram avaliados 89 ligamentos cruzados posterior de 85 pacientes com idade média de 69,79 anos, sendo 69 do sexo feminino, 16 do masculino. O LCP foi corado em hematoxilina-eosina e Tricrômio de Gomori e classificado quanto ao comprometimento histológico em leve, moderado e grave. A degeneração histológica foi correlacionada aos parâmetros idade, artrose radiográfica classificada por Ahlbäck (grau I ao V), eixo radiográfico tíbio-femoral (varo, neutro e valgo), e estado do ligamento cruzado anterior (LCA), presença ou ausência.Os achados histológicos de hipercelularidade, infiltração linfocitária crônica, proliferação vascular; presença de cistos; clones de condrócitos; degenerações colágena, fibrinóide, cartilaginosa ,gordurosa e mucoide foram correlacionados com o grau de degeneração do LCP e ao estado de conservação do LCA. RESULTADO: Não foram identificadas relações entre o grau de degeneração histológica do LCP e faixa etária (abaixo ou acima de 70 anos), sexo, classificação radiográfica de Ahlbäck e presença ou ausência do LCA. Os achados histológicos de degeneração fibrinóide, proliferação vascular e presença de cistos estiveram estatisticamente relacionados à degeneração histológica grave do LCP. CONCLUSÃO: Os parâmetros clínicos e radiográficos não foram capazes de predizer o grau de degeneração histológica do LCP .Os achados histológicos de degeneração fibrinóide, proliferação vascular e presença de cistos caracterizaram a degeneração histológica grave do LCP / OBJECTIVE: Evaluate the histologic degeneration pattern of the posterior cruciate ligament (PCL) in osteoarthrosis patients submitted to total knee replacement with a cruciate substituting prosthesis. The histologic degeneration was classified in mild, moderate and severe. The histologic pattern was related to clinical, per-operatory (presence or absence of anterior cruciate ligament) and radiographic parameters with the aim to settle if these parameters would be reliable to predict the PCL degeneration grade. METHODS: 89 PCLs from 85 patients, 16 men, 69 women, mean age 69, 79 years old. PCL was stained with hematoxylin and eosin and trichromium of Gomori. The PCL histologic degeneration was graded from normal-minimum to severe. The histologic PCL degeneration pattern was related to age, radiographic arthrosis classification (Ahlbäck - grades I to V), knee radiographic axis (varus, neutral, valgus) and to the ACL status (presence or absence).The histologic findings of hipercellularity, chronic lymphocit infiltration, neoangiogenesis, cysts, collagen degeneration (deg), fibrinoid deg, mucoid deg., cartilaginous, deg., fat deg. and condrocyte clones were related to the grade of PCL degeneration and to ACL status. RESULTS: There was no correlation of histologic degeneration to sex or age (above or below 70 years), arthrosis radiographic classification (Ahlbäck) and presence or absence of ACL. The histological findings of fibrinoid degeneration, vascular proliferation and cysts were statistically related to severe histologic LCP degeneration. CONCLUSION: The parameters studied were not capable of predicting the grade of LCP degeneration. The histological findings of fibrinoid degeneration, vascular proliferation and cysts were characteristic of severe PCL histologic degeneration

No description available.

INTRODUCTION. Frontal collisions have been observed to cause the severe injuries on heavy goods vehicle occupants, and the lower extremities have been frequently injured. Injuries of knee joints are rarely life threatening, however they tend to give long-term consequences. AIM. Evaluate non-lethal frontal impacts towards the knee joint of Total Human Model for Safety (THUMS) v4.0 using a cylindrical barrier. The main objectives are to 1) create local injury risk functions of the knee ligaments restraining frontal impacts, 2) simulate frontal impacts towards the knee joints of THUMS and3) prepare the Hybrid III (HIII)-model for corresponding frontal impacts conducted on THUMS. The intention is for future HIII-simulations to be cross-correlated with the responses from THUMS for the ability to estimate knee ligament strains by investigating impacts on HIII. METHODS. 1) Ligament risk curves of PCL, MCL and LCL were formulated by assembling mean strain threshold values and standard deviations from literature. Virtual values were generated from these pooled strain thresholds, creating the risk curves. 2) THUMS lower body was impacted by a cylindrical steel barrier at four different locations - middle of patella, middle of knee joint, upper tibia and below tibia tuberositas. Four impact velocities ranging from 8-14 km/h were used at each location, giving a total of 16 impacts. 3) The HIII-model was prepared by removing the upper body and inserting the cylindrical steel barrier into the model file. RESULTS. The strain threshold at 50% rupture risk for PCL resulted in 23.6±4.4%, 34.2±6.0% for MCL and 26.6±6.5% for LCL. The simulated THUMS PCL strains reached between 36%-58% for the highest velocity at the impact locations where tibia was involved. Both MCL and LCL gave an approximate 5% strain outcome. The resultant knee displacement for these impacts ranged between 22 mm - 32 mm. The knee displacements at the PCL strain threshold ranged between 14 mm - 16 mm. DISCUSSION and CONCLUSION. Most of the maximal PCL strains exceeded the PCL threshold with large margins. However, the knee displacement at the PCL strain threshold resulted in outcomes comparable to the thresholds used for HIIImodel. These results supported the obtained PCL threshold to be within a reasonable range.