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Purpose: To compare functional outcomes, residual instability, and rupture rates in patients with ligamentous hyperlaxity undergoing isolated anterior cruciate ligament (ACL) reconstruction or combined ACL and anterolateral ligament (ALL) reconstruction., Methods: Two groups of patients were evaluated and compared retrospectively. Both groups consisted of patients with ACL injuries and associated ligamentous hyperlaxity, defined based on the modified Beighton scale with a minimum score of 5. Group 1 patients underwent anatomical ACL reconstruction, and group 2 patients underwent anatomical ACL reconstruction combined with ALL reconstruction. Group 1 consisted of historical controls. The presence of associated meniscal injury, subjective International Knee Documentation Committee and Lysholm functional scores, KT-1000 measurements, the presence of a residual pivot-shift, and the graft rupture rate were evaluated. The study was performed at University of São Paulo in Brazil., Results: Ninety patients undergoing ACL reconstruction with ligamentous hyperlaxity were evaluated. The mean follow up was 29.6 ± 6.2 months for group 1 and 28.1 ± 4.2 months for group 2 (P = .51). No significant differences were found between the groups regarding Beighton scale, gender, the duration of injury before reconstruction, follow-up time, preoperative instability, or associated meniscal injuries. The mean age was 29.9 ± 8.1 years in group 1 and 27.0 ± 9.1 years in group 2 (P = .017). In the final evaluation, group 2 patients showed better anteroposterior clinical stability as evaluated by KT-1000 arthrometry (P = .02), better rotational stability as evaluated by the pivot-shift test (P = .03) and a lower reconstruction failure rate (21.7% [group 1] vs 3.3% [group 2]; P = .03). Clinical evaluations of postoperative functional scales showed no differences between the 2 groups (P = .27 for International Knee Documentation Committee; P = .41 for Lysholm)., Conclusions: Combined ACL and ALL reconstruction in patients with ligamentous hyperlaxity resulted in a lower failure rate and improved knee stability parameters compared to isolated ACL reconstruction. No differences were found in the functional scales., Level of Evidence: Level III, case control study., (Copyright © 2019 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: The anterolateral ligament (ALL) of the knee has recently been described in detail. Most studies of the ALL have been conducted in adults; therefore, little is known about the anatomy and histology of the ALL in younger patients, and nothing is known about the fetal presence of the ALL., Purpose: To evaluate the ALL in human fetuses to determine its presence or absence and to describe its microscopic anatomy and histological features compared with the findings of studies conducted in adults., Study Design: Descriptive laboratory study., Methods: Twenty human fetal cadaveric specimens were used. The mean age of the fetuses was 28.64 ± 3.20 weeks. The ALL was dissected in the anterolateral region of the knee, and its anatomic parameters, including its origin, insertion, and path in relation to known adjacent anatomic landmarks, in addition to its length, width, and thickness over the path toward the tibia, were measured. After dissection, the ALL was removed en bloc with a portion of the lateral meniscus for histological analysis of 4-μm sections, hematoxylin and eosin staining, and immunohistochemical staining for type I collagen., Results: The ALL was located in all dissected knees. Its origin was located at a mean distance of 1.87 mm from the origin of the lateral collateral ligament, with variations from the center of the lateral epicondyle to posterior and proximal to it, and it exhibited an anterior-inferior path toward the tibia, an insertion in the lateral meniscus approximately 2.08 mm anterior to the popliteal tendon, and another insertion in the tibia between the Gerdy tubercle and the fibular head at 2.46 mm below the articular cartilage. The histological sections of the ALL showed well-organized, dense collagenous tissue fibers with elongated fibroblasts (mean, 1631 fibroblasts/mm 2 ) and a predominance of type I collagen., Conclusion: The ALL is present during fetal development, with anatomic and histological features similar to those of the adult ALL., Clinical Relevance: The findings of this study help to better understand the ALL's anatomy and histology from the fetal period to adulthood. The study presents the existence of the ALL since fetal development, emphasizes the characterization of the ALL, and brings important information to future pediatric ALL lesion studies.

Objectives:: To clinically and epidemiologically characterize a population diagnosed with and treated for septic arthritis of the knee, to evaluate the treatment results and to analyze the differences between patients with positive and negative culture results, patients with Gram-positive and Gram-negative bacterial isolates and patients with S. aureus- and non-S. aureus-related infections., Methods:: One hundred and five patients with septic knee arthritis were included in this study. The clinical and epidemiological data were evaluated. Statistical analysis was performed to compare patients with and without an isolated causative agent, patients with Gram-positive and Gram-negative pathogens and patients with S. aureus-related and non S. aureus-related infections., Results:: Causative agents were isolated in 81 patients. Gram-positive bacteria were isolated in 65 patients and Gram-negative bacteria were isolated in 16 patients. The most commonly isolated bacterium was S. aureus. Comparing cases with an isolated pathogen to cases without an isolated pathogen, no differences between the studied variables were found except for the longer hospital stays of patients in whom an etiological agent was identified. When comparing Gram-positive bacteria with Gram-negative bacteria, patients with Gram-positive-related infections exhibited higher leukocyte counts. Patients with S. aureus-related infections were more frequently associated with healthcare-related environmental encounters., Conclusion:: S. aureus is the most common pathogen of septic knee arthritis. Major differences were not observed between infections with isolated and non-isolated pathogens and between infections with Gram-positive and Gram-negative bacteria. S. aureus infections were more likely to be associated with a prior healthcare environment exposure., Competing Interests: No potential conflict of interest was reported.

Background: The location of patellar and femoral fixation of the graft in medial patellofemoral ligament reconstructions has been widely discussed. This study aimed to assess the distances between different patellar and femoral fixation points to identify the least anisometric pairs of points., Methods: Ten cadaver knees were attached to an apparatus that simulated an active range of motion of 120°, with three metallic markers fixed onto the medial side of the patella, and seven markings onto the medial epicondyle. The examined points included the proximal patella pole (1), the patellar center (3), the midpoint between points 1 and 3 (2), a point directly on the epicondyle (6), points 5mm anterior (5) and posterior (7) to the epicondyle, points 5mm anterior to point 5 (4) and 5mm posterior to point 7 (8), and points 5mm proximal (9) and distal (10) to the epicondyle. The distances between patella and femur points were measured by a photogrammetry system at 15° intervals., Findings: The pair of points that exhibited the lowest average variability in distance, and hence was the most isometric, was the patella center combined with the anterior to the medial femoral epicondyle. The pairs of points that exhibited the highest average variability in distance, and hence were the least isometric, were the ones located distal or posterior to the medial femoral epicondyle, with less influence by the patellar location., Interpretation: Surgeons should avoid positioning the graft distally or posterior to the epicondyle due to the increase in anisometry., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The current study analyzed changes in anterior cruciate ligament (ACL) and lateral collateral ligament stress as a result of mechanical varus. In an exploratory pilot study, progressive mechanical varus was introduced to a male finite element model of the lower limb at different knee flexion angles. Nine situations were analyzed (combinations of 0°, 30°, and 60° knee flexion and 0°, 5°, and 10° varus). The ACL stress was measured via changes in section force, von Mises stress, and fiber stress. Lateral collateral ligament stress was measured via changes in section force. For all 3 measures of the ACL, maximum stress values were found in extension, stress decreased with flexion, and the effect of varus introduction was most significant at 30° flexion. With 60° flexion, varus introduction produced a decrease in section force and von Mises stress and a small increase in fiber stress. In all situations and stress measures except fiber stress at 60° flexion, stress was concentrated at the posterolateral bundle. For the lateral collateral ligament, the introduction of 5° and 10° varus caused an increase in section force at all degrees of flexion. Stress in the ligament decreased with flexion. Mechanical varus of less than 10° was responsible for increased ACL stress, particularly at 0° and 30° knee flexion, and for increased lateral collateral ligament stress at all degrees of flexion. Stress was mostly concentrated on the posterolateral bundle of the ACL. [Orthopedics. 2016; 39(4):e729-e736.]., (Copyright 2016, SLACK Incorporated.)

Background: Recent studies clearly characterize the anatomical parameters of the knee anterolateral ligament (ALL). The potential clinical importance of this ligament is exemplified by some patients with possible combined Anterior Cruciate Ligament (ACL) and ALL rupture who do not progress satisfactorily following isolated ACL reconstruction. Previous biomechanical studies have assessed the resistance parameters of the ALL in order to address potential reconstruction strategies; however, these have reported conflicting results. Thus, this study aimed to evaluate the linear resistance of the ALL by means of a biomechanical study in cadaveric knees., Methods: Fourteen cadaveric knees were used. The ALL was dissected, and all structures that connect the femur and the tibia, except for the ALL, were sectioned. The ALL was subjected to a tensile test with the knee around 30 to 40 degrees, in a way that the ALL was aligned with the machine. The strength at the maximum resistance limit, deformation and stiffness of the ALL were evaluated., Results: The mean maximum strength of the ALL was 204.8 +/- 114.9 N. The stiffness was 41.9 +/- 25.7 N/mm and the deformation 10.3 +/- 3.5 mm., Conclusion: The ALL has a mean ultimate tensile strength of 204.8 N. This suggests that simple bands of all autologous or homologous grafts commonly used in clinical practice for ligament reconstruction around the knee possess the required biomechanical resistance characteristics for ALL reconstruction.

Purpose: This study sought to determine the safety limits for performing a femoral bone tunnel to reconstruct the knee anterolateral ligament (ALL) by establishing its distance from the lateral collateral ligament (LCL) and the popliteus muscle tendon (PT) on the lateral femoral condyle., Methods: Anatomic study on 48 knee cadaveric specimens. The femoral attachments of the studied structures were isolated, and the distance between them was measured. For each cadaver, the percentage of cases in which at least 50 % of the LCL and PT would be injured when using 4- to 12-mm-diameter drills in an ALL reconstruction procedure was evaluated., Results: The LCL and PT were 3.8 mm and 10.2 mm distant from the ALL, respectively. A 4-mm tunnel would cause LCL injury in 8.3 % of cases, with increasing incidence of injury up to 87.5 % with a 12-mm drill. Injury to the PT would start with the 10-mm drill, causing injury in 2.0 % of cases., Conclusions: Performing a tunnel in the center of the ALL may cause an iatrogenic injury to the LCL origin. No cases of PT injury are expected to occur with drills smaller than 10 mm.

Introduction: Patellofemoral instability is a common knee disease. Its etiology is complex and variable, with many components making different contributions in each individual, resulting in several distinct clinical presentations. Our goal was to analyze the results of surgical treatment in our hospital over a period of 10 years., Patients and Methods: We analyzed 55 knees of 47 patients who underwent surgery for patellofemoral instability and were classified into 2 main groups: proximal realignment and combined proximal and distal realignment. Three other groups were analyzed according to the duration of preoperative symptoms: less than 1 year (group I); 1 to 10 years (group II); and more than 10 years (group III)., Results: There were 62% good results overall, with 78% good results in groups I and II. Group III had 81% bad results, showing that a late diagnosis of advanced disease results in a poor prognosis. In addition to late diagnosis, bad results were usually associated with incorrect diagnosis or choice of surgical technique. There was no significant difference between isolated proximal realignment and combined proximal and distal realignment in groups I or II, but in group III, the combined technique yielded better results., Discussion: Our results indicate that patellofemoral instability should be addressed in its early stages. Patients with long-lasting symptoms or more severe disease seem to achieve better results with combined techniques., Conclusion: Proximal and distal realignments produce better results than isolated proximal realignment in patients with joint degeneration or with greater duration of disease. The realignment surgery does not produce good results in patients with advanced disease.