The biomechanical effects of graft rotation on ACL reconstruction tunnel mismatch.

PURPOSE: Bone block protrusion out of the tibial tunnel due to a relatively long graft is a common complication in anterior cruciate ligament surgical reconstruction with a patellar tendon. One possible solution is to shorten the patellar tendon graft already fixed in the femur by applying external rotation. This study aimed to evaluate the degree of shortening and biomechanical changes in porcine patellar grafts subjected to relatively higher degrees of rotation. Data obtained with rotations of 0°, 540°, 720°, and 900° were compared. METHODS: Forty patellar porcine ligaments were subjected to biomechanical tests of degree of shortening, modulus of elasticity and maximum tension in the tendon before rupture. Tests were conducted using a universal mechanical testing machine and a computerized system for acquiring strength and deformation data. RESULTS: Progressive shortening of the patellar ligament occurred with rotations of 0°, 540° and 720°. However, the degree of shortening showed no statistically significant difference as rotation increased from 720° to 900°. Decreased modulus of elasticity was observed compared with the graft rotation at 0° in all groups tested, but no statistically significant differences were observed among 540°, 720° and 900°. The maximum tension of the patellar tendon showed no change before rupture, regardless of the degree of rotation. CONCLUSIONS: Rotating the patellar tendon is an efficient method for shortening a relatively long graft; however, more biomechanical studies are necessary to recommend this technique in clinical practice owing to the resulting decrease in graft stiffness that could compromise knee stability.

The Anterolateral Ligament: An Anatomic, Radiographic, and Biomechanical Analysis.

BACKGROUND: Recent publications have described significant variability in the femoral attachment and overall anatomy of the anterolateral ligament (ALL). Additionally, there is a paucity of data describing its structural properties. PURPOSE: Quantitative data characterizing the anatomic and radiographic locations and the structural properties of the ALL may be used to guide graft selection and placement and to facilitate the future development of an evidence-based approach to ALL reconstructions. STUDY DESIGN: Descriptive laboratory study. METHODS: Identification of the ALL was performed by a combined outside-in and inside-out anatomic dissection of 15 nonpaired fresh-frozen cadaveric knees. Quantitative anatomic relationships were calculated using a 3-dimensional coordinate measuring device. Measurements on anteroposterior (AP) and lateral radiographs were obtained by use of a picture archiving and communications system program. Structural properties were characterized during a single pull-to-failure test using a tensile testing machine. All anatomic, radiographic, and biomechanical measurements were reported as mean values and 95% CIs. RESULTS: The ALL was identified as a thickening of the lateral capsule coming under tension with an applied internal rotation at 30° of flexion. Its femoral attachment was located 4.7 mm (95% CI, 3.5-5.9 mm) posterior and proximal to the fibular collateral ligament attachment and coursed anterodistally to its anterolateral tibial attachment approximately midway between the center of the Gerdy tubercle and the anterior margin of the fibular head; the tibial attachment was located 24.7 mm (95% CI, 23.3-26.2 mm) and 26.1 mm (95% CI, 23.9-28.3 mm) from each structure, respectively. On the AP radiographic view, the ALL originated on the femur 22.3 mm (95% CI, 20.7-23.9 mm) proximal to the joint line and inserted on the tibia 13.1 mm (95% CI, 12.3-13.9 mm) distal to the lateral tibial plateau. On the lateral view, the femoral attachment was 8.4 mm (95% CI, 6.8-10.0 mm) posterior and proximal to the lateral epicondyle. The tibial attachment was 19.0 mm (95% CI, 17.1-20.9 mm) posterior and superior to the center of the Gerdy tubercle. The mean maximum load was 175 N (95% CI, 139-211 N) and the stiffness was 20 N/mm (95% CI, 16-25 N/mm). Failure occurred by 4 distinct mechanisms: ligamentous tear at the femoral (n = 4) or tibial (n = 1) attachment, midsubstance tear (n = 4), and bony avulsion of the tibial attachment (Segond fracture; n = 6). CONCLUSION: Defined ALL attachment locations can be reproducibly identified with intraoperative landmarks or radiographs. The biomechanical analysis suggests that most traditional soft tissue grafts are sufficient for ALL reconstruction. CLINICAL RELEVANCE: The ALL was consistently found in all knees. Segond fractures appear to occur primarily from the avulsion of the ALL.

Epidemiological study of cauda equina syndrome.

OBJECTIVE: : The primary purpose of this study was to determine the characteristics and outcomes of the patients admitted at our clinics diagnosed with cauda equina syndrome (CES). Secondarily, this study will serve as a basis for other comparative studies aiming at a better understanding of this condition and its epidemiology. METHODS: : We conducted a retrospective study by reviewing the medical records of patients diagnosed with CES and neurogenic bladder between 2005 and 2011. The following variables were analyzed: gender, age, etiology, topographic level of the lesion, time between disease onset and diagnosis, presence of neurogenic bladder, time between diagnosis and surgery, neurological damage and neurogenic bladder persistence. RESULTS: : Considering that CES is a rare condition, we were not able to establish statistic correlation between the analyzed variables and the outcomes of the disease. However, this study brought to light the inadequacy of our public health system in treating that kind of patient. CONCLUSION: : The study shows that despite the well-defined basis for managing CES, we noted a greater number of patients with sequels caused by this condition, than is seen in the literature. The delayed diagnosis and, consequently, delayed treatment, were the main causes for the results observed. Level of Evidence IV, Case Series .

Estudo epidemiológico da síndrome da cauda equina / Epidemiological study of cauda equina syndrome

Objetivo: O objetivo primário deste estudo é analisar as características e desfechos dos casos internados por síndrome da cauda equina (SCE) em nosso serviço. Secundariamente, este trabalho servirá de base para outros estudos comparativos visando um entendimento maior da doença e de sua epidemiologia. Métodos: estudo retrospectivo dos prontuários das internações por SCE no IOT-HCFMUSP no período de 2005 a 2011 com diagnósticos de SCE e bexiga neuropática. As seguintes variáveis foram analisadas: sexo, idade, etiologia da doença, nível topográfico da lesão, tempo de história da lesão até o diagnóstico, presença de bexiga neurogênica, tempo entre o diagnóstico da SCE e a cirurgia, reversão do déficit ou da bexiga neurogênica. Resultados: por tratar-se de uma doença rara, não conseguimos estabelecer correlações estatisticamente significativas entre as variáveis analisadas e os desfechos da doença. Porém, este estudo evidenciou deficiências do nosso sistema público de saúde quanto ao manejo desses pacientes. Conclusão: o trabalho mostra que apesar de bem definidas as bases para conduta da SCE, observamos um número maior de sequelas causadas pela patologia, do que visto na literatura. O atraso no diagnóstico e, a partir deste, do tratamento definitivo, foi a causa para o alto número de sequelas. Nível de evidência IV, Série de Casos.

Objective: The primary purpose of this study was to determinate the characteristics and outcomes of the patients admitted at our clinics diagnosed with cauda equina syndrome (CES). Secondarily, this study will serve as a basis for other comparative studies aiming the better understanding of this condition and its epidemiology. Methods: we conducted a retrospective study by reviewing the medical records of patients diagnosed with CES and neurogenic bladder between 2005 and 2011. The following variables were analyzed: gender, age, etiology, topographic level of the lesion, time between disease onset and diagnosis, presence of neurogenic bladder, time between diagnosis and surgery, neurological damage and neurogenic bladder persistence. Results: considering that CES is a rare condition, we were not able to establish statistic correlation between the analyzed variables and the outcomes of the disease. However, this study brought to light the inadequacy of our public health system in treating that kind of patient. Conclusion: The study shows that despite the well-defined basis for managing CES, we noted a greater number of patients with sequels caused by this condition, than it is seen in the literature. The delayed diagnosis and, consequently, delayed treatment, were the main causes for the results observed. Level of Evidence IV, Case Series.