An Unusual Cause of Posterior Knee Pain: Mucoid Degeneration of the Anterior Cruciate Ligament - Case Report / Uma causa incomum de dor posterior no joelho: degeneração mucóide do ligamento cruzado anterior - Relato de caso

Abstract Mucoid degeneration of the anterior cruciate ligament (ACL) is an uncommon cause of pain in the posterior region of the knee, of unknown pathophysiology and underdiagnosed. The best treatment modality is still under discussion. Resection of the lesion with partial ACL debridement has shown good results without the occurrence of instability. The authors present a case of mucoid degeneration of the ACL treated with resection of the mucoid degeneration and partial debridement of the ACL by arthroscopy.

Resumo A degeneração mucoide do ligamento cruzado anterior (LCA) é uma causa pouco frequente de dor na região posterior do joelho, de patofisiologia desconhecida e subdiagnosticada. A melhor modalidade de tratamento ainda está em discussão. A ressecção da lesão com desbridamento parcial do LCA tem apresentado bons resultados, sem a ocorrência de instabilidade. Os autores apresentam um caso de degeneração mucoide do LCA tratado com ressecção da degeneração mucoide e desbridamento parcial do LCA por artroscopia.

Risk Factors for Symptomatic Cyclops Lesion Formation after Anterior Cruciate Ligament Reconstruction / Fatores de risco para formação de lesão cyclops sintomática após a reconstrução do ligamento cruzado anterior

Abstract Objective To evaluate the incidence of symptomatic cyclops lesions requiring surgical treatment after anterior cruciate ligament (ACL) reconstruction and to establish possible intraoperative risk factors related to it. Methods Three hundred and eighty-nine patients aged between 18 and 50 years who underwent primary ACL reconstruction were retrospectively evaluated. Patients were divided into groups according to the presence or absence of symptomatic cyclops lesions, and their characteristics were compared. Patients with associated lesions that required additional surgical procedures (except anterolateral extra-articular procedures) were not included. The rate of symptomatic cyclops lesions was recorded and the following parameters were evaluated: age, gender, time from injury to surgery, graft type and diameter, femoral tunnel perforation technique, fixation type, presence of knee hyperextension, preservation of the ACL remnant, associated anterolateral extra-articular procedure, associated meniscal injury and participation in sports. Results 389 patients were evaluated and 26 (6.7%) patients developed cyclops. The patients with and without cyclops lesions did not differ in age, time from injury to surgery, graft type or diameter, surgical technique, femoral fixation method, presence of knee hyperextension, remnant preservation and associated meniscal injury. The group with cyclops lesion had a higher proportion of females (10 (38.4%) vs 68 (18.7%); OR = 2.7; p= 0.015), higher proportion of extra-articular reconstruction (18 (11.8%) vs 8 (3.4%); OR = 3.8; p= 0.001) and higher proportion of sports practice (23 (8.6%) vs 3 (2.5%); OR = 3.6; p= 0.026). Conclusion In our series, 6.7% of the patients required arthroscopic removal of cyclops lesions. Female gender, associated extra-articular reconstruction and sports practice were factors related to this lesion. Remnant preservation had no relationship with cyclops lesion formation.

Resumo Objetivo Avaliar a incidência de lesões cyclops sintomáticas que precisam de tratamento cirúrgico após a reconstrução do ligamento cruzado anterior (LCA) e estabelecer os possíveis fatores de risco intraoperatórios relacionados a elas. Métodos Trezentos e oitenta e nove pacientes com idades entre 18 e 50 anos submetidos à reconstrução primária do LCA foram avaliados de forma retrospectiva. Os pacientes foram divididos em grupos de acordo com a presença ou ausência de lesões cyclops sintomáticas e suas características foram comparadas. Não foram incluídos pacientes com lesões associadas que necessitassem de outros procedimentos cirúrgicos (à exceção de procedimentos extra-articulares ântero-laterais). A taxa de lesões cyclops sintomáticas foi registrada e os seguintes parâmetros foram avaliados: idade, sexo, tempo da lesão à cirurgia, tipo e diâmetro do enxerto, técnica de perfuração do túnel femoral, tipo de fixação, presença de hiperextensão do joelho, preservação do LCA remanescente, associação a procedimento extra-articular ântero-lateral, lesão de menisco associada e participação em esportes. Resultados Dos 389 pacientes avaliados, 26 (6,7%) desenvolveram lesão cyclops. Os pacientes com e sem lesão cyclops não diferiram quanto à idade, tempo da lesão à cirurgia, tipo ou diâmetro do enxerto, técnica cirúrgica, método de fixação femoral, presença de hiperextensão do joelho, preservação do LCA remanescente e lesão de menisco associada. O grupo com lesão cyclops apresentou mais mulheres (10 [38,4%] vs. 68 [18,7%]; razão de probabilidades [OR] = 2,7; p= 0,015), maior proporção de reconstrução extra-articular (18 [11,8%] vs. 8 [3,4 %]; OR = 3,8; p= 0,001) e maior proporção de prática esportiva (23 [8,6%] vs. 3 [2,5%]; OR = 3,6; p= 0,026). Conclusão Em nossa série, 6,7% dos pacientes necessitaram de remoção artroscópica das lesões cyclops. O sexo feminino, a reconstrução extra-articular associada e a prática esportiva foram fatores relacionados a essa lesão. A preservação do menisco remanescente não foi associada à formação de lesões cyclops.

Los Músculos Isquiosurales y su Capacidad Profiláctica sobre la Translación Tibial Anterior en Lesión de Ligamento Cruzado Anterior: Una Revisión Sistemática / The Hamstrings Muscles and their Prophylactic Capacity on Anterior Tibial Translation in Anterior Cruciate Ligament Injury: A Systematic Review

La ruptura de ligamento cruzado anterior (LCA) es la lesión de rodilla más común que se trata de una reconstruc- ción quirúrgica. El objetivo principal de esta revisión fue analizar la importancia de la función de los músculos isquiosurales como factor de riesgo de posibles lesiones de LCA. Se llevó a cabo siguiendo las normas Preferred Reported Item for Systematic Reviews and Meta- analyses (PRISMA). La fuente de la recopilación de datos fue la consulta directa de las bases de datos Pubmed, Sportdiscus, Web of Science y Scopus. Para la recuperación documental, se utilizaron varias palabras clave y se evaluó la calidad de los estudios que fueron seleccionados mediante la escala PEDro. Los déficits de la función muscular en los músculos isquiosurales se han relacionado con una mayor translación tibial anterior y, como consecuencia, un incremento del estrés tensional sobre el LCA entre los 10° y 45° de flexión de rodilla. Una co-activación de los músculos isquiosurales con el músculo cuádriceps femoral puede ser de gran ayuda para reducir los factores de riesgo de la lesión LCA.

SUMMARY: Anterior cruciate ligament (ACL) rupture is the most common knee injury to undergo surgery in the sports setting. The main objective of this review was to analyze the importance of hamstring function as a risk factor for potential ACL injury. It was conducted following the Preferred Reported Item for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The source of data collection was direct consultation of the Pubmed, Sportdiscus, Web of Science and Scopus databases. For documentary retrieval, several key words were used and the quality of the studies that were selected was assessed using the PEDro scale. Muscle function deficits in the hamstrings have been related to increased anterior tibial translation and, as a consequence, increased tensional stress on the ACL between 10° and 45° of knee flexion. A co-activation of the hamstrings with the quadriceps may be helpful in reducing the risk factors for ACL injury.

Graft Selection Between Tendon Autograft and Allograft in Anterior Cruciate Ligament Reconstruction Based on the Histological Perspective: A Meta-Analysis / Seleção de enxerto entre autoenxerto e aloenxerto de tendão na reconstrução do ligamento cruzado anterior com base na perspectiva histológica: uma metanálise

Abstract Objective The purpose of this meta-analysis is to compare ligament healing on autograft and allograft in anterior cruciate ligament (ACL) reconstruction. Methods The selection of appropriate studies was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We made a statistical analysis using a review manager. Electronic reports were searched using the PubMed, Medline, and Cochrane Library databases. The inclusion criteria were animal studies and cellular histology of both grafts as an outcome. Results The initial search revealed 412 potential articles. After duplicates were removed, 246 articles remained. Then, 14 articles were obtained and screened for relevance and eligibility. The relevant articles were searched manually, checking for eligibility and details in order not to miss included reports. Subsequently, 5 studies were included, with a total of 232 samples, reporting the biopsied results with quantitative histology of ligament healing between allograft and autograft. The biopsy samples in those studies were examined under light or electron microscope, to analyze the cellular distribution area and ligamentization stages in each group. Meta-analyses found significant difference between autograft and allograft (Heterogeneity, I2 = 89%; Mean Difference, 95% confidence interval [CI] =-34.92, -54.90, -14.93; p = 0.0006). There is also a significant difference on both graft in cellular count at over 24 weeks (Heterogeneity, I2 = 26%; Mean Difference, 95% CI = -14.59, -16.24, -12.94; p < 0.00001). Conclusion In the current meta-analysis, autograft shows a significant difference when compared to allograft, with more cellular accumulation and faster remodeling response on the ligamentization process being noticed in the former. However, a larger clinical trial will be needed to emphasize this literature's result.

Resumo Objetivo O objetivo desta metanálise comparar a cicatrização de ligamentos no autoenxerto e aloenxerto na reconstrução do ligamento cruzado anterior (LCA). Métodos A seleção dos estudos adequados foi realizada de acordo com as diretrizes de Relatórios Preferenciais para Revisões Sistemáticas e Metanálises (Preferred Reporting Items for Systematic Reviews and Meta-Analyses - PRISMA). Uma análise estatística foi feita usando um gerente de revisão. Os relatórios eletrônicos foram pesquisados usando os bancos de dados PubMed, Medline e Cochrane Library. Os critérios de inclusão foram estudos em animais e a histologia celular de ambos os enxertos como desfecho. Resultado A pesquisa inicial revelou 412 artigos potenciais. Após a retirada das duplicatas, restaram 246 artigos. Então, 14 artigos foram obtidos e selecionados pela relevância e elegibilidade. Os artigos relevantes foram pesquisados manualmente, verificando sua elegibilidade e detalhando os estudos para não perder os relatórios incluídos. Posteriormente, foram incluídos 5 estudos, com um total de 232 amostras, relatando os resultados de biópsia com histologia quantitativa de cicatrização de ligamento entre aloenxerto e autoenxerto. As amostras de biópsia nesses estudos foram examinadas sob microscópio leve ou eletrônico, para análise da área de distribuição celular e estágios de ligamentização em cada grupo. As metanálises encontraram diferença significativa entre autoenxerto e aloenxerto (Heterogeneidade, I2 = 89%; Diferença média, 95% intervalo de confiança [IC] =-34,92, -54,90, -14,93; p = 0,0006). Também há uma diferença significativa nosdoisenxertosnacontagem celular de mais de 24 semanas (Heterogeneidade, I2 = 26%; Diferença média, 95% IC = -14,59 , -16,24, -12,94; p < 0,00001). Conclusão Na presente metanálise, o autoenxerto mostra resultados significativos quando comparado ao aloenxerto, com mais acúmulo celular e resposta de remode-lagem mais rápida no processo de ligamentizaçãosendoobservadonoprimeiro.No entanto, será necessário um estudo clínico maior para enfatizar o resultado desta literatura.

Proprioception Analysis following Anterior Cruciate Ligament Reconstruction using Stabilometry: A Prospective, Longitudinal Study / Análise de propriocepção por estabilometria após a reconstrução do ligamento cruzado anterior: Um estudo prospectivo e longitudinal

Abstract Objective Commonly used methods for measuring proprioception have resulted in conflicting reports regarding knee proprioception with anterior cruciate ligament (ACL) rupture and the influence of ACL reconstruction. Methods One hundred subjects (50 patients with radiologically and arthroscopically confirmed unilateral ACL rupture and 50 normal controls) were assessed with regards to proprioception using dynamic single-leg stance postural stabilometry. Instrumented knee ligament laxity and knee outcome scores were also measured. Of the 50 patients in the ACL group, 34 underwent reconstruction and were reassessed postoperatively. Results There was a significant proprioceptive deficiency in the ACL group compared with their contralateral knee ( p < 0.001) and to the control group ( p = 0.01). There was asignificant improvement in knee proprioception following ACL reconstruction compared to preoperative findings ( p = 0.003). There was no correlation between ligament laxity measurements and outcome scores. A significant correlation was found preoperatively between outcome scores and proprioception measurements. This correlation was not found post-operatively. Pre-operative proprioception testing had asignificant correlation (r = 0.46) with post-operative proprioception ( p = 0.006). Conclusion Patients with an ACL rupture had a proprioceptive deficit which improved following ligament reconstruction. Knee outcome scores had a better correlation with proprioception than ligament laxity. Proprioception may be a superior objective measure than ligament laxity in quantifying functional knee deficits and outcomes in patients with ACL ruptures. Level of Evidence III Therapeutic Study; Prospective Longitudinal Case-Control Study.

Resumo Objetivo Os métodos comumente usados para medir a propriocepção resultaram em relatos conflitantes sobre a propriocepção do joelho com ruptura do ligamento cruzado anterior (LCA) e a influência da reconstrução do LCA. Métodos A propriocepção de 100 indivíduos (50 pacientes com ruptura unilateral do LCA confirmada à radiologia e artroscopia e 50 controles normais) foi avaliada por estabilometria postural dinâmica em apoio unipodal. A lassidão ligamentar do joelho instrumentado e suas pontuações de desfechos também foram medidas. Dos 50 pacientes do grupo LCA, 34 foram submetidos à reconstrução e reavaliados no período pós-operatório. Resultados O grupo LCA apresentou deficiência proprioceptiva significativa em relaçãoaojoelho contralateral ( p < 0,001) e ao grupo controle ( p = 0,01). A propriocepção do joelho melhorou de maneira significativa após a reconstrução do LCA em relação aos achados pré-operatórios ( p = 0,003). Não houve correlação entre as medidas de lassidão ligamentar e as pontuações de desfechos. Além disso, observamos uma correlação significativa entre as pontuações de desfechos e as medidas de propriocepção antes da cirurgia. Essa correlação não foi detectada no período pós-operatório. O teste pré-operatório de propriocepção teve correlação significativa ( r = 0,46) com a propriocepção pós-operatória ( p = 0,006). Conclusão Os pacientes com ruptura do LCA apresentaram déficit proprioceptivo que melhorou após a reconstrução ligamentar. As pontuações de desfecho do joelho tiveram melhor correlação à propriocepção do que a lassidão ligamentar. A proprio-cepção pode ser uma medida objetiva superior à lassidão ligamentar na quantificação de déficits funcionais e desfechos do joelho em pacientes com ruptura do LCA. Nível de Evidência III Estudo Terapêutico; Estudo de Caso-Controle Longitudinal Prospectivo.

Synovium and blood capillaries at the femoral attachment of anterior cruciate ligament are significantly abundant than those at the tibial attachment / Sinovial y capilares sanguíneos en la inserción femoral del ligamento cruzado anterior son significativamente más abundantes que los de la inserción tibial

SUMMARY: The anterior cruciate ligament (ACL) is a ligament that mainly controls the anterior and rotational mobility of the knee joint, and its surface is covered by a synovial membrane with large number of blood vessels. In general, nutritional supply to the ligament is from many capillaries in the adjacent synovium. However, statistical studies of the capillaries distributed to the ACL are insufficient. In this study, we examined cross-sectional histological images of the femoral attachment (femoral level), middle level of the tendon (middle level), and tibial attachment (tibial level) of the ACL and statistically analyzed blood capillary distribution among the three levels. The ACLs of 10 cadavers were divided into 5 equal sections, and 4mm-thick paraffin sections were made at the femoral level, middle level, and tibial level, and then hematoxylin-eosin (HE) staining were performed. The area of each transverse section was measured using Image-J 1.51n (U. S. National Institutes of Health, Bethesda, MD, USA). Fiber bundles of the ACL were relatively small and sparse in cross-sectional area at the femoral level and became larger and denser toward the tibial level. Many blood levels. The synovium at the attachment of ACL covered the surface of the fiber bundle and also penetrated deeply between the fiber bundles. In particular, the blood capillaries were densely distributed in the synovium at the femoral attachment rather than another two levels. Indeed, the number of capillaries were also most abundant in the femoral level. The cross-sectional ACL area at the femoral level is significantly small, however, the blood capillaries were most abundant. Therefore, when the ACL is injured, its reconstruction with preservation of the femoral ligamentous remnant may be clinically useful for remodeling of the grafted tendon.

El ligamento cruzado anterior (LCA) es un ligamento que controla principalmente la movilidad anterior y rotacional de la articulación de la rodilla, y su superficie está cubierta por una membrana sinovial con gran cantidad de vasos sanguíneos. En general, el suministro de nutrientes al ligamento proviene de muchos capilares en la sinovial adyacente. Sin embargo, los estudios estadísticos de los capilares distribuidos en el LCA son insuficientes. En este estudio, examinamos imágenes histológicas trans- versales de la inserción femoral (nivel femoral), el nivel medio del tendón (nivel medio) y la inserción tibial (nivel tibial) del LCA y analizamos estadísticamente la distribución de los capilares sanguíneos entre los tres niveles. Los LCA de 10 cadáveres se dividieron en 5 secciones iguales y se realizaron cortes en parafina de 4 µm de espesor a nivel femoral, medio y tibial, y luego se realizó tinción con hematoxilina-eosina (HE). El área de cada sección transversal se midió utilizando Image-J 1.51n (Institutos Nacionales de Salud de EE. UU., Bethesda, MD, EE. UU.). Los haces de fibras del LCA eran relativamente pequeños y escasos en el área de la sección transversal a nivel femoral y se hicieron más grandes y más densos hacia el nivel tibial. La membrana sinovial en la unión del LCA cubría la superficie del haz de fibras y también penetraba profundamente entre entre los haces de fibras. En particular, los capilares sanguíneos estaban densamente distribuidos en la unión femoral de la sinovial respecto a los otros dos niveles. De hecho, el número de capilares también fue más abundante a nivel femoral. El área transversal del LCA a nivel femoral era significativamente pequeña, sin embargo, los capilares sanguíneos fueron los más abundantes. Por lo tanto, cuando hay una lesión del LCA su reconstrucción con preservación del ligamento femoral remanente puede ser clínicamente útil para remodelar el tendón injertado.

Relationship of the Cruciate and Meniscofemoral Ligaments with the Knee Osteology. An Anatomical Study / Relação dos ligamentos cruzados e meniscofemorais com a osteologia do joelho: Um estudo anatômico

Abstract Objective To analyze the dimensions of the posterior cruciate ligament (PCL), anterior cruciate ligament (ACL), the presence of meniscus-femoral ligaments MFLs in human knees, and the correlation with the dimensions of the knee skeleton. Methods Anatomical study on 29 specimens of human knees in which we measured the length and width of the cruciate and meniscus-femoral ligaments and the dimensions of femoral and tibia condyles and the femoral notch. The ACL length was calculated with different degrees of knee flexion. The relationship between the ligaments and bone dimensions were analyzed. Results The length of the ACL and the PCL were similar. Posterior MFL was more frequent and longer than the anterior MFL. We found the posterior MFL in the 72.41% of the knees and anterior MFL in 20.69%. The ACL presented 30% of its maximum length up to 60°, approximately half of its length between 90° and 120°, reaching its maximum length at 170°. We found a strong correlation between the length of the ACL and that of the PCL (p= 0.001). However, the lengths of the ACL and PCL were not related with the bone dimensions. Conclusion We have found no correlations between the cruciate and MFLs and the anatomical dimensions of the intercondylar notch and the proximal tibia and distal femur. The presence of the posterior MFL was more frequent and longer than that of the anterior ligament.

Resumo Objetivo Analisar as dimensões do ligamento cruzado posterior (LCP), do ligamento cruzado anterior (LCA), a presença de ligamentos meniscofemorais (LMFs) em joelhos humanos e a correlação com as dimensões do esqueleto do joelho. Métodos Estudo anatômico em 29 espécimes de joelhos humanos nos quais medimos o comprimento e a largura dos ligamentos cruzado e meniscofemoral e as dimensões dos côndilos femorais e tibiais e do entalhe femoral. O comprimento do LCA foi calculado com diferentes graus de flexão do joelho. Analisou-se a relação entre os ligamentos e as dimensões ósseas. Resultados O comprimento do LCA e do LCP foram semelhantes, LMF posterior foi mais frequente e mais longo do que o LMF anterior. Foram encontradas LMF posterior em 72,41% dos joelhos e LMF anterior em 20,69%. O LCA apresentou 30% de seu comprimento máximo até 60°, aproximadamente metade de seu comprimento entre 90° e 120°, atingindo seu comprimento máximo com flexão de 170°. Encontramos uma forte correlação entre o comprimento do LCA e do LCP (p= 0,001). No entanto, os comprimentos do LCA e do LCP não estavam relacionados com as dimensões ósseas. Conclusão Não encontramos correlações entre os ligamentos cruzado e meniscofemoral e as dimensões anatômicas do entalhe intercondilar e da tíbia proximal e do fêmur distal. A presença do LMF posterior foi mais frequente e maior que a do ligamento anterior.

Calculation of the Minimal Important Clinical Difference of the Lysholm and IKDC Scores After Anterior Cruciate Ligament Reconstruction / Cálculo da mínima diferença clínica importante dos escores Lysholm e IKDC após reconstrução do ligamento cruzado anterior

Abstract Objective To calculate the minimal important clinical difference (MICD) value for the Lysholm and International Knee Documentation Committee (IKDC) scores in a sample of patients submitted to anterior cruciate ligament reconstruction. Methods Primary, observational, retrospective, analytical study of participants submitted to anterior cruciate ligament reconstruction from March 2019 to December 2020 by the same surgeon, with a minimum follow-up of 6 months, analysis of knee function in the pre- and postoperative period by the Lysholm and IKDC scores, and answer to an anchor question at 6 months postoperatively for the calculation of the MICD of each score. Results A total of 59 patients participated in the study, with a mean age of 27.1 ± 5.7 years old. In the comparison between pre- and postoperative scores of all groups, there was an increase in values with statistical significance after intervention. The MICD was 5.5 for the Lysholm score, and the MICD value for the IKDC score could not be determined. Conclusion For the Lysholm score, the calculation of the MICD value by the anchor question method in the sample evaluated was 5.5. It was not possible to determine the value of the MICD for the IKDC score.

Resumo Objetivo Calcular o valor da mínima diferença clinicamente importante (MDCI) para os escores de Lysholm e International Knee Documentation Commitee (IKDC) na amostra de pacientes submetidos a reconstrução de ligamento cruzado anterior. Métodos Estudo primário, observacional, retrospectivo, analítico, de participantes submetidos a reconstrução do ligamento cruzado anterior no período de março de 2019 a dezembro de 2020, pelo mesmo cirurgião, com seguimento mínimo de 6 meses, análise da função do joelho no período pré e pós-operatório pelos escores de Lysholm e IKDC, e resposta a uma pergunta âncora aos 6 meses de seguimento pós-operatório, para o MDCI de cada escore. Resultados Participaram do estudo 59 pacientes, com média de idade de 27,1 ± 5,7 anos. Na comparação dos escores pré- e pós-operatórios de todos os grupos, observa-se aumento dos valores com significância estatística após a intervenção. A MDCI foi de 5,5 para o escore de Lysholm, não tendo sido possível determinar o valor para o IKDC. Conclusão O cálculo do valor da MDCI pelo método da pergunta âncora, na amostra avaliada, foi de 5,5 para o escore de Lysholm. Não foi possível determinar o valor da MDCI para o IKDC.

Application of continuous nursing based on hybrid electronic platform and fragmented time concept in out-of-hospital rehabilitation of patients with anterior cruciate ligament reconstruction / 中国实用护理杂志

Objective:To explore the application effect of continuous nursing based on hybrid electronic platform and fragmentation time in the out-of-hospital rehabilitation of patients with anterior cruciate ligament reconstruction.Methods:This was a randomized controlled study. From April 2020 to October 2021, a total of 90 patients undergoing anterior cruciate ligament reconstruction in Weifang People′s Hospital were selected as the research objects by convenience sampling. Forty patients from April to December 2020 were selected as control group, and 45 patients from January to October 2021 were selected as intervention group. The control group implemented routine discharge guidance and follow-up, while the intervention group was given continuous nursing plan based on the concept of hybrid electronic platform and fragmented time. Before operation and 1, 3 and 6 months after operation, the knee range of motion and Lysholm score of patients in the two groups were analyzed. At 1, 3 and 6 months after operation, the rehabilitation exercise compliance score, self-efficacy score and knee stability examination of the two groups were analyzed.Results:A total of 41 patients in each group completed the study. At 1 month after operation, the knee range of motion, Lysholm score, rehabilitation exercise compliance score and self-efficacy score of intervention group were (96.46 ±3.58) ° and (53.54 ± 6.57), (69.17 ± 6.27), (4.01 ± 0.38) points, respectively. In the control group, they were (89.02 ± 4.22)° and (45.02 ± 7.61), (56.78 ± 8.45), (3.61 ± 0.42) points. At 3 months after operation, they were (136.83 ± 4.30)° and (72.76 ± 4.96), (60.71 ± 5.87), (4.97 ± 0.32) points in the intervention group, (133.54 ± 3.58)° and (69.83 ± 6.65), (56.73 ± 8.57), (4.83 ± 0.45) points in the control group, respectively. At 6 months after operation, they were (139.39 ± 1.99)° and (85.61 ± 6.11), (57.71 ± 7.41), (6.58 ± 0.96) points in the intervention group, (138.29 ± 2.65)° and (81.80 ± 6.38), (47.90 ± 6.02), (6.35 ± 1.23) points in the control group, respectively. The knee range of motion, Lysholm score and rehabilitation exercise compliance score of the intervention group were better than those of the control group at 1, 3 and 6 months after operation, and the differences were statistically significant ( t values were 2.12-8.61, all P<0.05). The self-efficacy score of the intervention group was higher than that of the control group at 1 month after operation, and the difference was statistically significant ( t=4.57, P<0.05). Conclusions:The continuous nursing program based on hybrid electronic platform and fragmented time can improve the knee function of patients with anterior cruciate ligament reconstruction in the early postoperative period, improve the compliance of rehabilitation exercise and the level of early self-efficacy.

Short-Term Changes of Graft Viscosity after Anterior Cruciate Ligament Reconstruction / 医用生物力学

Objective To study the short-term variation patterns of graft viscosity after anterior cruciate ligament reconstruction (ACLR) surgery. Methods Six male New Zealand rabbits were selected. The ACLR animal model of unilateral knee was made with Achilles tendon as the graft. The experimental rabbits were euthanized 15 days after ACLR surgery, with removal of the graft, healthy anterior cruciate ligament (ACL) and Achilles tendon. The cross-sectional area and viscosity coefficient of the graft were measured, and the creep experiments were carried out under equilibrium conditions of 0.1 MPa and 1 MPa, respectively. The viscosity coefficent was calculated. Variation patterns of graft viscosity were summarize. The grafts were compared with healthy ACL. Results The cross-sectional area of the graft increased slowly within 15 days after ACLR surgery. The viscosity of ACL and graft changed nonlinearly. The viscosity coefficient was quite different under different stresses. The viscosity coefficient of the graft decreased with the time after ACLR surgery, which was more obviously under the condition of low stress. Conclusions The results are helpful to guide the implementation of early postoperative rehabilitation plan after ACLR surgery .

Long-term outcomes of lateral femoral notch after early anterior cruciate ligament reconstruction / 中国骨伤

OBJECTIVE@#To investigate the outcome of lateral femoral notch (LFN) after early anterior cruciate ligament (ACL) reconstruction and evaluate the recovery of knee joint function after the operation.@*METHODS@#The clinical data of 32 patients who underwent early ACL reconstruction from December 2015 to December 2019 were retrospectively analyzed. The study included 18 males and 14 females, aged 16 to 54 years old, with an average age of (25.39±2.82) years. The body mass index (BMI) of the patients ranged from 20 to 30 kg/cm2, with an average of (26.15±3.09) kg/cm2. Among them, 6 cases were caused by traffic accidents, 19 by exercise, and 7 by the crush of heavy objects. MRI of all patients showed LFN depth was more than 1.5 mm after injury, and no intervention for LFN was performed during surgery. Preoperative and postoperative depth, area, and volume of LFN defects were observed by MRI data. International Cartilage Repair Society (ICRS) score, Lysholm score, Tegner activity levels, and knee injury and osteoarthritis outcome score (KOOS) were analyzed before and after the operation.@*RESULTS@#All patients were followed up from 2 to 6 years with an average of (3.28±1.12) years. There was no significant difference in the defect depth of LFN from (2.31±0.67) mm before the operation to (2.53±0.50) mm at follow-up (P=0.136). The defect area of LFN was decreased from (207.55±81.01)mm2 to (171.36±52.69)mm2 (P=0.038), and the defect volume of LFN was decreased from (426.32±176.54) mm3 to (340.86±151.54)mm3 (P=0.042). The ICRS score increased from (1.51±0.34) to (2.92±0.33) (P<0.001), the Lysholm score increased from (35.37±10.54) to (94.46±8.45) (P<0.001), and the Tegner motor score increased from (3.45±0.94) to (7.56±1.28), which was significantly higher than that of the preoperative data (P<0.001). The KOOS score of the final follow-up was 90.42±16.35.@*CONCLUSION@#With the increase of recovery time after anterior cruciate ligament reconstruction, the defect area and volume of LFN decreased gradually, but the defect depth remained unchanged. The knee joint function of the patients significantly improved. The cartilage of the LFN defect improved, but the repair effect was not good.

Correlation between spatial inclination of Blumensaat line and anterior cruciate ligament injury based on EOS biplanar 3D imaging system / 中国骨伤

OBJECTIVE@#To explore correlation between femoral mechanical axis and Blumensaat line (FMBL) angle of knee joint (angle between Blumensaat line and femoral mechanical axis), α angle (angle between Blumensaat line and axis of distal femur in sagittal plane) on EOS biplane imaging and non-contact anterior cruciate ligament(ACL) injury, and evaluate angle for its accuracy in predicting the populations prone to non-contact ACL injury.@*METHODS@#From February 2018 to October 2020, EOS imaging and clinical data from 88 patients (176 knees) with unilateral non-contact ACL injury were retrospectively analyzed, including 53 males and 35 females, aged from 18 to 45 years old with an average of (30.3±6.2) years old, 48 patients on the left side and 40 patients on the right side. The patients were divided into ACL-affected group and ACL-health group according to side of ACL injuries, and 51 patients (51 knees) with non-ACL identified from EOS database were included in normal control group, including 28 males and 23 females, aged from 20 to 44 years old with an average of (31.6±5.5) years old, 26 patients on the left side and 25 patients on the right side. Full-length EOS imaging of skeleton extremitatis inferioris among three groups were reconstructed to 3D images of skeletal system with EOS software, and then FMBL angle and α angle were measured on the images. Univariate binary Logistic regression analysis was performed to determine the influence of the univariate(FMBL angle or α angle) on ACL status(normal or torn). And the angle cutoff value for univariate was selected based on receiver operating characteristics curve (ROC) to got the best accuracy.@*RESULTS@#There was no statistically significant difference in age, gender and side distribution between ACL-injured group and normal control group(P>0.05). Statistical analyses (one-way ANOVA) indicated no significant difference in FMBL angle between ACL-injured knee group (32.8±2.3)° and ACL-injured contralateral knee group(32.5±2.3)°(P>0.05), but the values between two groups were significantly lower than that in normal control group (37.0±2.0)°(P<0.001). There was no statistically significant difference in α angle among three groups (P>0.05). Univariate binary Logistic regression analysis demonstrated that FMBL angle was risk factor for non-contact ACL injury[OR=0.433, 95%CI(0.330, 0.569), P<0.001]. The area under ROC curve for FMBL angle was 0.909[95%CI(0.861, 0.958), P<0.001], and the sensitivity and specificity were 70.5% and 98.0% respectively, cut-off value was 33.7°.@*CONCLUSION@#FMBL angle formed by Blumensaat line and femoral mechanical axis is one of the risk factors for non-contact ACL injury and has good predictive accuracy. The general population with FMBL angle below 33.7° may be increased risk for ACL injury.

Establishment of anterior cruciate ligament reconstruction model in cynomolgus monkey with autogenous hamstring tendon transplantation / 中国修复重建外科杂志

OBJECTIVE@#To investigate the feasibility of establishing an anterior cruciate ligament (ACL) reconstruction model using hamstring tendon autograft in cynomolgus monkeys.@*METHODS@#Twelve healthy adult male cynomolgus monkeys, weighing 8-13 kg, were randomly divided into two groups ( n=6). In the experimental group, the ACL reconstruction model of the right lower limb was prepared by using a single bundle of hamstring tendon, and the ACL of the right lower limb was only cut off in the control group. The survival of animals in the two groups was observed after operation. Before operation and at 3, 6, and 12 months after operation, the knee range of motion, thigh circumference, and calf circumference of the two groups were measured; the anterior tibial translation D-value (ATTD) was measured by Ligs joint ligament digital body examination instrument under the loads of 13-20 N, respectively. At the same time, the experimental group underwent MRI examination to observe the graft morphology and the signal/ noise quotient (SNQ) was caculated.@*RESULTS@#All animals survived to the end of the experiment. In the experimental group, the knee range of motion, thigh circumference, and calf circumference decreased first and then gradually increased after operation; the above indexes were significantly lower at 3 and 6 months after operation than before operation ( P<0.05), and no significant difference was found between pre-operation and 12 months after operation ( P>0.05). In the control group, there was no significant change in knee range of motion after operation, showing no significant difference between pre- and post-operation ( P>0.05), but the thigh circumference and calf circumference gradually significantly decreased with time ( P<0.05), and the difference was significant when compared with those before operation ( P<0.05). At 6 and 12 months after operation, the thigh circumference and calf circumference were significantly larger in the experimental group than in the control group ( P<0.05). At 3 and 6 months after operation, the knee range of motion was significantly smaller in the experimental group than in the control group ( P<0.05). Under the loading condition of 13-20 N, the ATTD in the experimental group increased first and then decreased after operation; and the ATTD significantly increased at 3, 6 months after operation when compared with the value before operation ( P<0.05). But there was no significant difference between the pre-operation and 12 months after operation ( P>0.05). There was no significant change in ATTD in the control group at 3, 6, and 12 months after operation ( P>0.05), and which were significantly higher than those before operation ( P<0.05). At each time point after operation, the ATTD was significantly smaller in the experimental group than in the control group under the same load ( P<0.05). The MRI examination of the experimental group showed that the ACL boundary gradually became clear after reconstruction and was covered by the synovial membrane. The SNQ at each time point after operation was significantly higher than that before operation, but gradually decreased with time, and the differences between time points were significant ( P<0.05).@*CONCLUSION@#The ACL reconstruction model in cynomolgus monkey with autogenous hamstring tendon transplantation was successfully established.

Effectiveness of anterior cruciate ligament reconstruction with personalized femoral locator based on apex of deep cartilage / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effectiveness of anterior cruciate ligament (ACL) reconstruction assisted by personalized femoral locator based on the apex of deep cartilage (ADC) combined with patient imaging data.@*METHODS@#Between January 2021 and January 2022, a total of 40 patients with primary ACL rupture were selected and randomly divided into study group (ACL reconstruction assisted by personalized femoral locator based on ADC) and control group (ACL reconstruction assisted by intraoperative fluoroscopy and traditional femoral locator), with 20 cases in each group. There was no significant difference in gender, age, body mass index, affected side, cause of injury, and preoperative International Knee Documentation Committee (IKDC) score, Lyshlom score, and Tegner score between the two groups ( P>0.05). IKDC score, Lyshlom score, and Tegner score were used to evaluate the functional recovery of the affected knee before operation and at 3, 6, and 12 months after operation. CT scan and three-dimensional reconstruction were performed before and after operation to measure the horizontal distance from ADC to the anterior cartilage margin (L) and the horizontal distance from ADC to the center of the femoral canal (I), and the anteroposterior position of the bone canal (R) was calculated by I/L; the distance from the center to the distal cartilage margin (D) was measured on the two-dimensional cross section; the R value and D value were compared between the two groups.@*RESULTS@#The operation time of the study group was significantly less than that of the control group [ MD=-6.90 (-8.78, -5.03), P<0.001]. The incisions of the two groups healed by first intention, and no complication such as intra-articular infection, nerve injury, and deep vein thrombosis of lower limbs occurred. There was no significant difference in the R value and D value between the preoperative simulated positioning and the actual intraoperative positioning in the study group [ MD=0.52 (-2.85, 3.88), P=0.758; MD=0.36 (-0.39, 1.11), P=0.351]. There was no significant difference in the actual intraoperative positioning R value and D value between the study group and the control group [ MD=1.01 (-2.57, 4.58), P=0.573; MD=0.24 (-0.34, 0.82), P=0.411]. The patients in both groups were followed up 12-13 months (mean, 12.4 months). The IKDC score, Lysholm score, and Tegner score of the two groups increased gradually with time, and there were significant differences between pre- and post-operation ( P<0.05). There was no significant difference in the scores between the two groups at each time point after operation ( P>0.05).@*CONCLUSION@#The personalized femoral locator based on ADC can accurately assist the femoral tunnel positioning in ACL reconstruction, which can shorten the operation time when compared with traditional surgical methods, and achieve satisfactory early effectiveness.

Three-dimensional kinematic analysis of knee joint after anterior cruciate ligament reconstruction with personalized femoral positioner based on apex of deep cartilage / 中国修复重建外科杂志

OBJECTIVE@#To investigate the changes of knee joint kinematics after anterior cruciate ligament (ACL) reconstruction assisted by personalized femoral positioner based on the apex of deep cartilage (ADC).@*METHODS@#Between January 2021 and January 2022, a total of 40 patients with initial ACL rupture who met the selection criteria were randomly divided into the study group (using the personalized femoral positioner based on ADC design to assist ACL reconstruction) and the control group (not using the personalized femoral positioner to assist ACL reconstruction), with 20 patients in each group. Another 20 volunteers with normal knee were collected as a healthy group. There was no significant difference in gender, age, body mass index, and affected side between groups ( P>0.05). Gait analysis was performed at 3, 6, and 12 months after operation using Opti _ Knee three-dimensional knee joint motion measurement and analysis system, and the 6 degrees of freedom (flexion and extension angle, varus and valgus angle, internal and external rotation angle, anteroposterior displacement, superior and inferior displacement, internal and external displacement) and motion cycle (maximum step length, minimum step length, and step frequency) of the knee joint were recorded. The patients' data was compared to the data of healthy group.@*RESULTS@#In the healthy group, the flexion and extension angle was (57.80±3.45)°, the varus and valgus angle was (10.54±1.05)°, the internal and external rotation angle was (13.02±1.66)°, and the anteroposterior displacement was (1.44±0.39) cm, the superior and inferior displacement was (0.86±0.20) cm, and the internal and external displacement was (1.38±0.39) cm. The maximum step length was (51.24±1.29) cm, the minimum step length was (45.69±2.28) cm, and the step frequency was (12.45±0.47) step/minute. Compared with the healthy group, the flexion and extension angles and internal and external rotation angles of the patients in the study group and the control group decreased at 3 months after operation, and the flexion and extension angles of the patients in the control group decreased at 6 months after operation, and the differences were significant ( P<0.05); there was no significant difference in the other time points and other indicators when compared with healthy group ( P>0.05). In the study group, the flexion and extension angles and internal and external rotation angles at 6 and 12 months after operation were significantly greater than those at 3 months after operation ( P<0.05), while there was no significant difference in the other indicators at other time points ( P>0.05). There was a significant difference in flexion and extension angle between the study group and the control group at 6 months after operation ( P<0.05), but there was no significant difference of the indicators between the two groups at other time points ( P>0.05).@*CONCLUSION@#Compared with conventional surgery, ACL reconstruction assisted by personalized femoral positioner based on ADC design can help patients achieve more satisfactory early postoperative kinematic results, and three-dimensional kinematic analysis can more objectively and dynamically evaluate the postoperative recovery of knee joint.

Risk factors for contralateral anterior cruciate ligament injury after primary anterior cruciate ligament reconstruction / 中国修复重建外科杂志

OBJECTIVE@#To investigate the risk factors of contralateral anterior cruciate ligament (ACL) injury after primary ACL reconstruction.@*METHODS@#A retrospective review was conducted on the 716 patients with ACL injury who received primary ACL reconstruction surgery and met the selection criteria between January 2012 and September 2018. After a mean follow-up period of 7.6 years (range, 4-10 years), 65 patients (9.1%) experienced contralateral ACL injury (injured group) and 651 patients (90.9%) did not (uninjured group). There was no significant difference in age, body mass index, and preoperative Lachman test degree between groups ( P>0.05). However, the proportion of female in the injured group was significantly higher than that of male ( P<0.05), and the preoperative posterior tibial slope (PTS) was significantly higher than that of the uninjured group ( P<0.05). Using the outcome of contralateral ACL injury as the dependent variable, the clinical data of the patient was first used as the independent variable, and univariate COX regression was used to analyze the prognostic influencing factors. Then, the indicators with differences in univariate COX regression were used as the independent variable, and multivariate COX regression was used to analyze the independent risk factors affecting prognosis. Log-Rank (Mantel-Cox) test was used to test and analyze the occurrence time of contralateral ACL injury in patients of different genders; X-tile software was used to analyze the occurrence time of contralateral ACL injury in patients with different PTS using Log-Rank (Mantel-Cox) test and PTS cut-off values.@*RESULTS@#Univariate COX regression analysis showed that gender and PTS were influence factors for contralateral ACL injury ( P<0.05); further multivariate COX regression analysis showed that female and increased PTS were independent risk factors for contralateral ACL injury ( P<0.05). The Log-Rank (Mantel-Cox) test results showed that the contralateral ACL injury occurred in female at 8.853 (8.600, 9.106) years, which was significantly shorter than that in male [9.661 (9.503, 9.819) years] ( χ 2=20.323, P<0.001). Using X-tile software to analyze the cut-off value of PTS, it was found that the cut-off value of PTS for contralateral ACL injury was 10.92°. According to the Log-Rank (Mantel-Cox) test, it was found that the contralateral ACL injury occurred in 5.762 (4.981, 6.543) years in patients with PTS≥10.92°, which was significantly shorter than patients with PTS<10.92° [9.751 (9.650, 9.853) years]( χ 2 =302.479, P<0.001).@*CONCLUSION@#Female and PTS≥10.92° after primary ACL reconstruction are independent risk factors for contralateral ACL injury.

Progress in evaluation of return to sports after anterior cruciate ligament reconstruction / 中国修复重建外科杂志

OBJECTIVE@#To summarize the evaluation methods of return to sports (RTS) after anterior cruciate ligament reconstruction (ACLR) in recent years, in order to provide reference for clinical practice.@*METHODS@#The literature related to the RTS after ACLR was searched from CNKI, Wanfang, PubMed, and Foreign Medical Information Resources Retrieval Platform (FMRS) databases. The retrieval range was from 2010 to 2023, and 66 papers were finally included for review. The relevant literature was summarized and analyzed from the aspects of RTS time, objective evaluation indicators, and psychological evaluation.@*RESULTS@#RTS is the common desire of patients with ACL injury and doctors, as well as the initial intention of selecting surgery. A reasonable and perfect evaluation method of RTS can not only help patients recover to preoperative exercise level, but also protect patients from re-injury. At present, the main criterion for clinical judgement of RTS is time. It is basically agreed that RTS after 9 months can reduce the re-injury. In addition to time, it is also necessary to test the lower limb muscle strength, jumping, balance, and other aspects of the patient, comprehensively assess the degree of functional recovery and determine the different time of RTS according to the type of exercise. Psychological assessment plays an important role in RTS and has a good clinical predictive effect.@*CONCLUSION@#RTS is one of the research hotspots after ACLR. At present, there are many related evaluation methods, which need to be further optimized by more research to build a comprehensive and standardized evaluation system.

Posterior cruciate ligament reconstruction: are the results similar to anterior cruciate ligament reconstruction? / Reconstrução do ligamento cruzado posterior: os resultados são similares à reconstrução do ligamento cruzado anterior?

ABSTRACT Objective: To report and compare the results of posterior cruciate ligament (PCL) and anterior cruciate ligament (ACL) reconstructions. Methods: In total, 42 patients were retrospectively evaluated, 20 with isolated PCL injuries (group 1) and 22 with isolated ACL ones (group 2) who were subjected to arthroscopic ligament reconstruction with autologous grafts and followed up for at least two years. To evaluate the results in group 1, objective IKDC and Lysholm scores, posterior drawer tests, and evaluations by a KT-1000 arthrometer were used, whereas for group 2, subjective IKDC and Lysholm score and the Lachman test were employed. To compare groups, objective IKDC and Lysholm scores and assessment via a KT-1000 arthrometer were considered. Results: Intragroup analysis showed improved results for all variables (p < 0.001) in both groups. Comparisons between groups showed a significant difference in objective IKDC scores (p < 0.001), but no such disparities for Lysholm ones (p = 0.052), clinical tests (p = 0.058) or evaluation by KT-1000 (p = 0.129). Conclusion: Treatment restored knee stability and function in both groups. Comparisons between groups showed that PCL reconstructions had inferior results than ACL ones according to patients' objective IKDC scores. Level of Evidence II, Retrospective Study.

RESUMO Objetivo: Reportar e comparar os resultados da reconstrução do ligamento cruzado posterior (LCP) e do ligamento cruzado anterior (LCA). Métodos: Foram avaliados retrospectivamente 42 pacientes: 20 com lesão isolada do LCP (grupo 1) e 22 com lesão isolada do LCA (grupo 2), submetidos à reconstrução ligamentar artroscópica com enxertos autólogos e acompanhados por pelo menos dois anos. Para avaliação dos resultados no grupo 1, foram utilizados o escore do International Knee Documentation Committee (IKDC) objetivo, escore de Lysholm, teste da gaveta posterior e avaliação pelo artrômetro KT-1000; e, para o grupo 2, foram utilizados o IKDC subjetivo, escore Lysholm e teste de Lachman. Para comparação entre os grupos, foram considerados o IKDC objetivo, escore Lysholm e avaliação pelo artrômetro KT-1000. Resultados: Ambos os grupos demonstraram melhora dos resultados na análise intragrupo em todas as variáveis (p < 0,001). Na comparação intergrupos, observou-se diferença significativa no IKDC objetivo (p < 0,001), não sendo observada diferença no escore Lysholm (p = 0,052), nos testes clínicos (p = 0,058) ou na avaliação pelo KT-1000 (p = 0,129). Conclusão: A estabilidade e função do joelho foram restauradas em ambos os grupos. Na comparação intergrupos, a reconstrução do LCP apresentou resultados inferiores à reconstrução do LCA no critério IKDC objetivo. Nível de Evidência II, Estudo Retrospectivo.

Evaluation of the anterolateral ligament of the knee in magnetic resonance mri: case series / Avaliação do ligamento anterolateral do joelho em exames de ressonância magnética: série de casos

ABSTRACT Objective: To evaluate the citation of the ligament in the magnetic resonance imaging (MRI) reports and confirm its presence and injury in the images of exams performed in the acute phase retrospectively. Methods: In total, 103 patients who underwent anterior cruciate ligament (ACL) reconstruction in 2019 were included. The images were reanalyzed by two radiologists. Results: In the first analysis, only one report mentioned the anterolateral ligament (ALL) and its injury (0.97%). On reanalysis, ALL was visualized in almost all cases (95% and 97%). An injury was found in 53 (51.5%) cases by radiologist A and in 56 (54.4%) cases by radiologist B. The injury was diagnosed by both in 39 (37.9%) cases (p < 0.0001). Radiologists disagreed regarding the injury (Kappa = 0.411). Conclusion: The reports failed to describe the ligament and diagnose a significant number of injuries. The analysis of conventional resonance images still presents divergences in the diagnosis of ALL injury associated with the ACL among radiologists. Level of Evidence IV, Case Series.

RESUMO Objetivo: Avaliar, de forma retrospectiva, a citação do ligamento anterolateral (LAL) em laudos de ressonância magnética (RM) e confirmar sua presença e lesão nas imagens de exames feitos na fase aguda. Métodos: Foram incluídos 103 pacientes submetidos à reconstrução do ligamento cruzado anterior (LCA) em 2019, cujas imagens foram reanalisadas por dois radiologistas. Resultados: Em primeira análise, apenas um laudo citava o LAL e sua lesão (0,97%); enquanto na reanálise, o LAL foi visualizado em quase todos os casos (95% pelo radiologista A e 97% pelo radiologista B). Foi encontrada lesão em 53 (51,5%) casos pelo radiologista A e 56 (54,4%) pelo radiologista B. Lesão foi diagnosticada por ambos em 39 (37,9%) casos (p < 0,0001). Houve divergência entre os radiologistas com relação à lesão (KappaL = 0,411). Conclusão: Os laudos deixaram de descrever o ligamento e diagnosticar um número significativo de lesões. A análise das imagens convencionais de ressonância ainda gera divergências no diagnóstico da lesão do LAL associada ao LCA entre os radiologistas. Nível de Evidência IV, Série de Casos.

Patellar fracture in anterior cruciate ligament reconstruction: in vitro analysis / Fratura patelar na reconstrução do ligamento cruzado anterior: análise in vitro

ABSTRACT Objective: To determine, by biomechanical analysis, safe patellar cut limits in anterior cruciate ligament (ACL) reconstruction that minimize fracture risks. Methods: From three-dimensional reconstruction, triangular cuts were made in the patella, with a depth of 6.5 mm and variable width and length (10 to 20 mm and 8 to 12 mm, respectively, both with an interval of 1 mm). The combinations of cuts constituted 55 models for tests, with five variations in width and 11 variations in length, tested with the finite element method (FEM). Results: The mean of the localized principal maximum (traction force) values was 4.36 Pa (SD 0.87 ± 0.76) and the localized principal minimum (compression force) was −4.33 Pa (SD 1.05 ± 1.11). Comparing width and length to the tension force of the values of the main maximum, we found statistical significance from 11 mm for width and 13 mm for length. Conclusion: In ACL reconstruction, the removal of the patellar bone fragment is safe for fragments smaller than 11 mm in width and 13 mm in length, which corresponds to 24% of the width and 28% of the length of the patella used. Level of Evidence II, Comparative Prospective Study.

RESUMO Objetivo: Determinar, por meio de análise biomecânica, os limites de corte patelar seguros para a reconstrução do ligamento cruzado anterior (LCA) e que minimizem riscos de fratura. Métodos: A partir de reconstrução tridimensional, foram feitos cortes triangulares na patela, com profundidade de 6,5 mm e largura e comprimento variáveis (8 a 12 mm e 10 a 20 mm), respectivamente, com intervalo de 1 mm). As combinações dos cortes constituíram 55 modelos para ensaios, com 5 variações de largura e 11 variações de comprimento, ensaiados por meio do método dos elementos finitos (MEF). Resultados: A média dos valores da máxima principal localizada (força de tração) foi de 4,36 Pa (DP 0,87 ± 0,76), e a mínima principal localizada (força de compressão) foi de −4,33 Pa (DP 1,05 ± 1,11). Comparando largura e comprimento à força de tensões dos valores da máxima principal, houve significância estatística a partir de 11 mm para largura e 13 mm para comprimento. Conclusão: Na reconstrução do LCA, a retirada do fragmento ósseo patelar mostrou-se segura para fragmentos menores que 11 mm de largura e 13 mm de comprimento, o que corresponde a 24% da largura e 28% do comprimento da patela utilizada. Nível de Evidência II, Estudo Prospectivo Comparativo.