Ultrasonography imaging of the anterolateral ligament using real-time virtual sonography

Real-Time Virtual Sonography-Guided Ossicle Removal in Unresolved Osgood-Schlatter Disease

Osgood-Schlatter disease (OSD) reduces participation in sports activities for adolescents, and, in unresolved cases of the disease in which daily life or sports activity after skeletal maturity are affected, surgical intervention to remove the ossicle is performed to alleviate symptoms. We present a real-time virtual sonography (RVS)-guided ossicle removal in unresolved OSD. The knee joint angle is set at 20°, which is the same position used in magnetic resonance imaging. A 1.5-cm longitudinal skin incision is made at the medial side of the tuberosity. An ultrasound probe covered with a sterile sleeve is then placed longitudinally at the level of tuberosity. The forceps is inserted to peel the patellar tendon off the posterior side of the ossicle. Then the anterior side of the ossicle is peeled off in both the transverse and longitudinal views. When the ossicle is unstable enough, forceps are used to grasp the ossicle and carefully remove it. RVS can see magnetic resonance imaging information in the surrounding area beyond what can be detected by the ultrasound probe, and RVS enables easy determination of the anatomical position of the ossicle, and removal of the ossicle is achieved with low invasiveness.

Spondylolisthesis and mismatch deformity affect outcomes after total knee arthroplasty

BACKGROUND

Little published data currently exist regarding the potential relationships between spondylolisthesis, mismatch deformity, and clinical outcomes following total knee arthroplasty (TKA). We hypothesize that preexisting spondylolisthesis will result in decreased functional outcomes after TKA.

METHODS

This retrospective cohort comparison of 933 TKAs was performed between January 2017 and 2020. TKAs were excluded if they were not performed for primary osteoarthritis (OA) or if preoperative lumbar radiographs were unavailable/inadequate to measure the degree of spondylolisthesis. Ninety-five TKAs were subsequently available for inclusion and divided into two groups: those with spondylolisthesis and those without. Within the spondylolisthesis cohort, pelvic incidence (PI) and lumbar lordosis (LL) were calculated on lateral radiographs to determine the difference (PI-LL). Radiographs with PI-LL > 10° were then categorized as having mismatch deformity (MD). The following clinical outcomes were compared between the groups: need for manipulation under anesthesia (MUA), total postoperative arc of motion (AOM) both pre-MUA or post-MUA/revision, incidence of flexion contracture, and a need for later revision.

RESULTS

Forty-nine TKAs met the spondylolisthesis criteria, while 44 did not have spondylolisthesis. There were no significant differences in gender, body mass index, preoperative knee range of motion (ROM), preoperative AOM, or opiate use between the groups. TKAs with spondylolisthesis and concomitant MD were more likely to have MUA (p = 0.016), ROM < 0-120 (p < 0.014), and a decreased AOM (p < 0.02) without interventions.

CONCLUSION

Preexisting spondylolisthesis by itself may not have adverse effect clinical results following TKA. However, spondylolisthesis increases the likelihood of developing MD. In those with both spondylolisthesis and concomitant mismatch deformities, patients had statistically and clinically significantly decreased in postoperative ROM/AOM and increased need for MUA. Surgeons should consider clinical/radiographic assessments of patients with chronic back pain who present for total joint arthroplasty.

LEVEL OF EVIDENCE

Level 3.

Minimally invasive anatomic reconstruction of the anterolateral ligament with ipsilateral gracilis tendon: a kinematic in-vitro study

Purpose

The anterolateral ligament (ALL) has been defined as a key stabilizer of internal tibial rotation at 35° or more of knee flexion, with a minimal primary or secondary stabilizing role in the AP direction. This study aimed to demonstrate that anatomical reconstruction of the ALL confers rotational stability equal to that of the uninjured knee. Hypothesis: anteroposterior (AP) and rotatory laxity will significantly vary after ALL tenotomy and ALL reconstruction with the author’s previously described technique.

Methods

After ultrasound (US) ALL identification, different kinematic measurements were performed with an image-less Computer-Assisted Navigation System with dedicated software for Laxity Analysis in 5 knee specimens. Anteroposterior (AP) translations and varus/valgus (VV) and Internal-External (IE) rotations were evaluated by two trained orthopedic surgeons before ALL section, after ALL section, and after ALL anatomical reconstruction with doubled ipsilateral autologous gracilis tendon.

Results

ALL resection significantly increased laxity in IE rotations with knee 90° flexed (IE90) and AP translation with tibia internally rotated and the knee 30° flexed (APlat) (p < 0.05). ALL reconstruction significantly reduced laxity in IE90 and APlat (p < 0.05) and reduced VV rotations at 30° of flexion (VV30) (p < 0.05).

There were no statistically significant elongation differences between native ALL and reconstructed ALL (graft) during laxity tests. The inter-operator repeatability of the tests was excellent for each measurement.

Conclusions

ALL acted as an important internal tibial rotation restrain at 90° and a significant (secondary) AP stabilizer at 30° of knee flexion. The presented ALL reconstruction technique significantly restored the increase of knee laxity produced by the ALL section.

Scientific level

Case-Controlled Laboratory Study, Level III.

The Anterolateral Ligament of the Knee

The femoral attachment of the anterolateral ligament (ALL) of the knee is still under debate, but the tibial attachment is consistently between Gerdy's tubercle and the fibular head. The structure is less identifiable and more variable in younger patients. The ALL likely plays a role in rotational stability, but its impact on anterior stability is less clear. Numerous ALL reconstruction techniques have been described. Biomechanical analysis of these techniques has not shown clear benefits, but this literature is limited by the heterogeneity of techniques, graft choices, and study methodology. Clinical studies of combined anterior cruciate ligament (ACL) and ALL reconstruction are few but promising in lowering the risk of an ACL reinjury. To our knowledge, there are no studies showing the clinical outcomes of combined ACL and ALL reconstruction in pediatric patients, who are at higher risk for ACL graft failure than adults.

Truly Existing or Hyped up? Unravelling the Current Knowledge Regarding the Anatomy, Radiology, Histology and Biomechanics of the Enigmatic Anterolateral Ligament of the Knee Joint

Ever since its description, anterolateral ligament (ALL) of the knee joint remains as the hotspot of controversies. Though it has been described under various descriptions, the structure gained its limelight when it was christened as anterolateral ligament by Claes in 2013. The main reason for the controversies around it is the lack of concrete evidences regarding its attachments, morphology, biomechanical aspects and radiological appearance. Similarly the role of ALL in pivot shift phenomenon also remains as a point of debate. The advocates of ALL suggest that because of its ability to modulate internal rotation and attachment to the lateral meniscus, ALL contributes to the pivot shift phenomenon. Similarly, the orientation of ALL stands as the reason for varied documentation with respect to imaging techniques. With the growing body of evidence, it is imperative to fix our stand regarding the structure because, if found to be morphologically persistent, it can be used for concomitant anterolateral stabilization along with anterior cruciate ligament reinforcement surgeries. The present review tries to systematically review the anatomy, variations in classifications, descriptions, histology, radiology and biomechanical features of ALL. At the end of the review, we would like to find the answer for the question: Is ALL a distinct ligamentous structure located at the anterolateral aspect of the knee? What is the contribution of it to the tibial internal rotation stability?

Computed tomography (CT), X-ray, and MRI evaluation of two anterolateral knee reconstruction techniques: lateral extra-articular tenodesis (LET) and the anterolateral ligament (ALL) reconstruction

The anterolateral ligament (ALL) and capsule of the knee are anatomical structures involved in rotational stability and pivot-shift control. As such, it has been demonstrated that the extra-articular anterolateral procedures improve clinical outcome when performed as an augmentation of the anterior cruciate ligament (ACL) reconstruction in specific groups of patients. This review describes the postoperative imaging findings of two techniques used to perform these procedures, using magnetic resonance imaging (MRI), computed tomography (CT), and radiography. The first technique described is the lateral extra-articular tenodesis (LET), which uses a strip of the iliotibial band that is harvested, passed underneath the lateral collateral ligament (LCL) and fixed posterior, and proximal to the lateral femoral epicondyle (LFE), preserving ITB insertion on Gerdy's tubercle. The second technique described is the ALL reconstruction, a procedure that attempts to recreate the anatomy of the ALL, using most often a gracilis autograft. In this procedure, femoral fixation is performed proximal and posterior to the LFE, and tibial fixation is slightly distal to the joint line, halfway from Gerdy's tubercle to the fibular head. The main objective of this review is to provide an overview of the postoperative imaging aspects of these two procedures with MRI, CT, and radiography and to describe possible complications. As they become more common, it is important for the radiologist and the orthopedic surgeon to understand their particularities in combination with the already well-known ACL reconstruction.

[Research progress in anterolateral ligament of knee]

Objective

To review research progress in the anterolateral ligament (ALL) of knee, and provide a clinical reference for diagnosis and treatment of ALL injury.

Methods

The literature on the diagnosis and treatment of ALL injury was widely reviewed. The incidence, anatomy, biomechanics, injury mechanism, and treatment status of ALL were summarized.

Results

The ALL contributes to the effect of controlling the internal rotation and anterior translation of the tibia, which affects the axial migration of the knee. ALL injury can be diagnosed according to the signs and MRI examination. Currently, no consensus exists for the surgical indications of ALL injury, but most surgeons tend to perform ALL reconstruction in patients requiring anterior cruciate ligament (ACL) reconstruction or revision surgery with higher pivot-shift tests. At present, various techniques have been used for ALL reconstruction, and there is no optimal technique. In addition, the long-term effectiveness of ALL reconstruction is unclear due to the lack of high-quality studies and long-term postoperative follow-up.

Conclusion

The ALL contributes to maintaining knee stability, and the ALL reconstruction technique and its effectiveness still need further research.

Siam-U-Net: encoder-decoder siamese network for knee cartilage tracking in ultrasound images

The tracking of the knee femoral condyle cartilage during ultrasound-guided minimally invasive procedures is important to avoid damaging this structure during such interventions. In this study, we propose a new deep learning method to track, accurately and efficiently, the femoral condyle cartilage in ultrasound sequences, which were acquired under several clinical conditions, mimicking realistic surgical setups. Our solution, that we name Siam-U-Net, requires minimal user initialization and combines a deep learning segmentation method with a siamese framework for tracking the cartilage in temporal and spatio-temporal sequences of 2D ultrasound images. Through extensive performance validation given by the Dice Similarity Coefficient, we demonstrate that our algorithm is able to track the femoral condyle cartilage with an accuracy which is comparable to experienced surgeons. It is additionally shown that the proposed method outperforms state-of-the-art segmentation models and trackers in the localization of the cartilage. We claim that the proposed solution has the potential for ultrasound guidance in minimally invasive knee procedures.

Inter-rater reliability of an ultrasound protocol to evaluate the anterolateral ligament of the knee

Objectives: The aim of this study was to validate an ultrasound protocol for evaluating the anterolateral ligament of the knee. Methods: A Thiel technique cadaveric specimen was used to validate an optimal scanning position and develop an ultrasound protocol to evaluate the anterolateral ligament. Three musculoskeletal sonographers acquired short- and long-axis images of the anterolateral ligament in 36 knees from 18 healthy volunteers. Anterolateral ligament length, thickness, width, and distance between anterolateral ligament insertion and lateral tibia plateau were measured. Intraclass Correlation Coefficient (ICC) was calculated. Results: The inter-rater reliability for anterolateral ligament thickness was poor, ICC = 0.35 (95% CI: –0.06–0.63). The inter-rater reliability for anterolateral ligament length and width was good, ICC = 0.80 (95% CI 0.64–0.89), ICC = 0.88 (95% CI 0.79–0.94), respectively; and the inter-rater reliability for the distance between insertion and lateral tibia plateau was excellent, ICC = 0.96 (95% CI 0.93–0.98). Conclusions: Ultrasonography is a reliable method for evaluating the anterolateral ligament. There is an excellent reliability for the distal part of the anterolateral ligament. As injuries usually occur in this part of the ligament, this protocol may be used to evaluate the anterolateral ligament in patients with suspected anterior cruciate ligament tears in clinical practice.

Identification of Normal and Injured Anterolateral Ligaments of the Knee: A Systematic Review of Magnetic Resonance Imaging Studies

PURPOSE

To identify the normal and injured magnetic resonance imaging appearance of the anterolateral ligament (ALL).

METHODS

A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed and Cochrane Library electronic databases were used to search for studies that reported the imaging outcomes of the appearance of the ALL. Two authors performed the searches in duplicate up to April 30, 2018, and interobserver agreement was calculated. The methodologic quality of included articles was assessed using an adaptation of the Arrivé methodologic quality scale for clinical studies of radiologic examinations.

RESULTS

From the original 270 records, a total of 24 studies (κ = 0.94) comprising 2,427 knees in 2,388 patients (mean age, 33.3 years; 66% male patients; 63% with anterior cruciate ligament [ACL] injury) were included. The ALL appeared in 51% to 100% of all assessed knees (71%-100% in ACL-injured knees and 64%-97% in uninjured knees) and was injured in 11% to 79% of ACL-injured knees. Reliability rates varied considerably (0.04-1.0 for intraobserver and 0.143-1.0 for interobserver agreement), and the entire portion of the ligament was often not seen. The tibial insertion was seen in 21% to 96% of cases, followed by the meniscal (range, 0%-100%) and femoral (range, 0%-90%) insertions. The mean methodologic quality score was 5.1 ± 1.8 out of a possible score of 9.

CONCLUSIONS

High variability was found in the identification of normal and injured ALL definition methods and the respective magnetic resonance imaging findings. Reliability rates varied considerably, and the entire portion of the ligament was often not seen.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II to IV studies.

Lateral Augmentation Procedures in Anterior Cruciate Ligament Reconstruction: Anatomic, Biomechanical, Imaging, and Clinical Evidence

BACKGROUND

There has been an increasing interest in lateral-based soft tissue reconstructive techniques as augments to anterior cruciate ligament reconstruction (ACLR). The objective of these procedures is to minimize anterolateral rotational instability of the knee after surgery. Despite the relatively rapid increase in surgical application of these techniques, many clinical questions remain.

PURPOSE

To provide a comprehensive update on the current state of these lateral-based augmentation procedures by reviewing the origins of the surgical techniques, the biomechanical data to support their use, and the clinical results to date.

STUDY DESIGN

Systematic review.

METHODS

A systematic search of the literature was conducted via the Medline, EMBASE, Scopus, SportDiscus, and CINAHL databases. The search was designed to encompass the literature on lateral extra-articular tenodesis (LET) procedures and the anterolateral ligament (ALL) reconstruction. Titles and abstracts were reviewed for relevance and sorted into the following categories: anatomy, biomechanics, imaging/diagnostics, surgical techniques, and clinical outcomes.

RESULTS

The search identified 4016 articles. After review for relevance, 31, 53, 27, 35, 45, and 78 articles described the anatomy, biomechanics, imaging/diagnostics, surgical techniques, and clinical outcomes of either LET procedures or the ALL reconstruction, respectively. A multitude of investigations were available, revealing controversy in addition to consensus in several categories. The level of evidence obtained from this search was not adequate for systematic review or meta-analysis; thus, a current concepts review of the anatomy, biomechanics, imaging, surgical techniques, and clinical outcomes was performed.

CONCLUSION

Histologically, the ALL appears to be a distinct structure that can be identified with advanced imaging techniques. Biomechanical evidence suggests that the anterolateral structures of the knee, including the ALL, contribute to minimizing anterolateral rotational instability. Cadaveric studies of combined ACLR-LET procedures demonstrated overconstraint of the knee; however, these findings have yet to be reproduced in the clinical literature. The current indications for LET augmentation in the setting of ACLR and the effect on knee kinematic and joint preservation should be the subject of future research.

Anatomy of the Anterolateral Ligament of the Knee: A Systematic Review

PURPOSE

To conduct a systematic literature review to search for studies on the anatomy of the anterolateral ligament (ALL) of the knee, presenting the most accepted findings, as well as the evolution of anatomic information on this structure.

METHODS

We reviewed the PubMed, MEDLINE, and ClinicalKey databases for anatomic studies on the ALL, involving cadaveric, histologic, and biochemical dissection and/or anatomic imaging. The primary data researched were the presence of the ligament; measures of length, width, and thickness; ligament path; insertions; number of bands; histologic assessment; and innervation.

RESULTS

We identified 53 studies. The ALL was found in 82.87% of adult dissections (more easily visualized in fresh cadavers), 74.07% of fetal dissections, and 84.80% of magnetic resonance imaging (MRI) studies. In 29 articles, the ALL was found in 100% of cases. There are 3 ALL insertion points: femoral, tibial, and meniscal. Histologic sections showed dense, well-organized collagen fibers, with an average of 121 fibroblasts/mm² in adults, in addition to the presence of vascular and nervous tissue. MRI was shown to be a good examination tool to visualize the ALL, primarily in the coronal plane and with T2-weighted images.

CONCLUSIONS

The ALL is a distinct structure in the anterolateral portion of the knee. It exhibits typical ligament characteristics and can be visualized on imaging examinations, especially MRI. It has a femoral attachment near the lateral epicondyle, with a trend in recent years showing it to be located posterior and proximal to it, following an anteroinferior trajectory, with an insertion into the lateral meniscus and proximal tibia at the midpoint between the fibular head and Gerdy tubercle. Among the studies, the length of the ALL varied from 30.41 to 59.0 mm, the width ranged between 4.0 and 7.0 mm, and the thickness ranged between 1.0 and 2.0 mm.

CLINICAL RELEVANCE

During the past few years, much controversy has been raised about the correct anatomy of the ALL. The main clinical relevance of this study is not only to end the discussion about the ALL's existence but also to clarify and synthesize the main evidence on the ALL's anatomy, mainly the currently most accepted attachments according to the recent literature, to enable more precise development of biomechanical settings and surgical techniques.

Use of ultrasonography to evaluate the dynamics of the infrapatellar fat pad after anterior cruciate ligament reconstruction: a feasibility study

PURPOSE

There has been no specific study on the quantitative morphological changes that occur in the infrapatellar fat pad (IPFP) after anterior cruciate ligament (ACL) reconstruction. We used ultrasonography to evaluate the dynamics of the IPFP in knees after ACL reconstruction using the contralateral knees as controls.

METHODS

We enrolled 31 patients 3 months after they underwent ACL reconstruction. The thickness of the superficial part of the IPFP was measured using longitudinally oriented ultrasound images of the anterior part of both knees at 90° and 10° flexion. We then used these data to calculate the ratio of the change in thickness.

RESULTS

At 90° knee flexion, the superficial part of the IPFP was significantly thinner in the reconstructed knees (9.3 ± 3.4 mm) than in the contralateral knees (11.8 ± 4.6 mm). The thickness change ratio was significantly smaller in the reconstructed knees (188.6 ± 64.7%) than in the contralateral knees (249.7 ± 73.8%).

CONCLUSION

When assessed 3 months after ACL reconstruction, the thickness of the superficial part of the IPFP at 90° knee flexion and the thickness change ratio of the IPFP were both significantly lower in the reconstructed knees than in the contralateral knees.

Influence of the Anterolateral Ligament on Knee Laxity: A Biomechanical Cadaveric Study Measuring Knee Kinematics in 6 Degrees of Freedom Using Dynamic Radiostereometric Analysis

Background:

An anterior cruciate ligament (ACL) rupture often occurs during rotational trauma to the knee and may be associated with damage to extracapsular knee rotation–stabilizing structures such as the anterolateral ligament (ALL).

Purpose:

To investigate ex vivo knee laxity in 6 degrees of freedom with and without ALL reconstruction as a supplement to ACL reconstruction.

Study Design:

Controlled laboratory study.

Methods:

Cadaveric knees (N = 8) were analyzed using dynamic radiostereometry during a controlled pivotlike dynamic movement simulated by motorized knee flexion (0° to 60°) with 4-N·m internal rotation torque. We tested the cadaveric specimens in 5 successive ligament situations: intact, ACL lesion, ACL + ALL lesion, ACL reconstruction, and ACL + ALL reconstruction. Anatomic single-bundle reconstruction methods were used for both the ACL and the ALL, with a bone-tendon quadriceps autograft and gracilis tendon autograft, respectively. Three-dimensional kinematics and articular surface interactions were used to determine knee laxity.

Results:

For the entire knee flexion motion, an ACL + ALL lesion increased the mean knee laxity (P < .005) for internal rotation (2.54°), anterior translation (1.68 mm), and varus rotation (0.53°). Augmented ALL reconstruction reduced knee laxity for anterior translation (P = .003) and varus rotation (P = .047) compared with ACL + ALL–deficient knees. Knees with ACL + ALL lesions had more internal rotation (P < .001) and anterior translation (P < .045) at knee flexion angles below 40° and 30°, respectively, compared with healthy knees. Combined ACL + ALL reconstruction did not completely restore native kinematics/laxity at flexion angles below 10° for anterior translation and below 20° for internal rotation (P < .035). ACL + ALL reconstruction was not found to overconstrain the knee joint.

Conclusion:

Augmented ALL reconstruction with ACL reconstruction in a cadaveric setting reduces internal rotation, varus rotation, and anterior translation knee laxity similar to knee kinematics with intact ligaments, except at knee flexion angles between 0° and 20°.

Clinical Relevance:

Patients with ACL injuries can potentially achieve better results with augmented ALL reconstruction along with ACL reconstruction than with stand-alone ACL reconstruction. Furthermore, dynamic radiostereometry provides the opportunity to examine clinical patients and compare the recontructed knee with the contralateral knee in 6 degrees of freedom.

A novel test for assessment of anterolateral rotatory instability of the knee: the tibial internal rotation test (TIR test)

Background

Rotational instability of the knee may persist after anterior cruciate ligament (ACL) reconstruction, which may be due to insufficiency of anterolateral stabilizing structures. However, no reliable diagnostic tool or physical examination test is available for identifying patients with anterolateral rotatory instability (ALRI). As shown in cadaveric studies, static internal rotation of the knee is increased in higher flexion angles of the knee after severing the anterolateral structures. This might also be the case in patients with an ACL-deficient knee and concomitant damage to the anterolateral structures. The objective of this study is to assess anterolateral rotatory instability of the knee during physical examination with a tibial internal rotation test.

Methods

ACL-injured knees of 52 patients were examined by two examiners and side-to-side differences were compared. Both lower legs were internally rotated by applying manual internal rotation torque to both feet in prone position with the knees in 30°, 60° and 90° of flexion. For quantification of the amount of rotation in degrees, a torque adapter on a booth was used. Intra-rater, inter-rater and rater-device agreement were determined by calculating kappa (κ) for the tibial internal rotation test.

Results

Tibial internal rotation is increased in 19.2% of the patients with ACL injury according to the tibial internal rotation test. Good intra-rater agreement was found for the tibial internal rotation test, κ_C = 0.63 (95%CI -0.02-1.28), p = 0.015. Fair inter-rater agreement was found, κ_F = 0.29 (95%CI 0.02–0.57), p = 0.038. Good rater-device agreement was found, κ_C = 0.62 (95%CI 0.15–1.10), p = 0.001.

Conclusion

The tibial internal rotation test shows increased tibial internal rotation in a small amount of patients with ACL injury. Even though no gold standard for assessment of increased tibial internal rotation of the knee is available yet, the test can be of additional value. It can be used for assessment of internal rotatory laxity of the knee as part of ALRI in addition to the pivot shift test. No clinical implications should yet be based on this test alone.

Electronic supplementary material

The online version of this article (10.1186/s40634-018-0141-9) contains supplementary material, which is available to authorized users.

Editorial Commentary: Looking Outside the Box With Ultrasound in an Anterior Cruciate Ligament-Deficient Knee: Welcome to Surgery 2.0

Perspectives on the anterolateral ligament have changed greatly since the first articles were published that cast doubt on the existence of this structure. The current debate is centered on how to best analyze it. Surgeons are increasingly focusing on the knee's secondary restraints. It is important to understand that magnetic resonance imaging is not the only imaging modality available to us.

The Anterolateral Complex and Anterolateral Ligament of the Knee

The anterolateral structures of the knee have recently garnered considerable interest regarding their role in rotatory knee instability related to anterior cruciate ligament tears. Isolated anterior cruciate ligament reconstruction may not always restore rotatory stability of the knee. In these patients, additional procedures, such as lateral reconstruction or tenodesis, may be indicated. The anatomy of the anterolateral structures of the knee has been well described. Histologic and anatomic studies have reported conflicting findings regarding the presence of a discrete ligament. The biomechanical role of the anterolateral capsule in restraining internal tibial rotation has been described as negligible. The existing body of research on the anterolateral knee structures provides insight into the composition of the anterolateral complex of the knee.

Three-Dimensional Virtual Sonographic Cystoscopy for Detection of Ureterocele in Duplicated Collecting Systems in Children

OBJECTIVES

Ureterocele is a sac-like dilatation of terminal ureter. Precise anatomic delineation is of utmost importance to proceed with the surgical plan, particularly in the ectopic subtype. However, the level of ureterocele extension is not always elucidated by the existing imaging modalities and even by conventional cystoscopy, which is considered as the gold standard for evaluation of ureterocele. This study aims to evaluate the accuracy of three-dimensional virtual sonographic cystoscopy (VSC) in the characterization of ureterocele in duplex collecting systems.

METHODS

Sixteen children with a mean age of 5.1 (standard deviation 1.96) years with transabdominal ultrasonography-proven duplex system and ureterocele were included. They underwent VSC by a single pediatric radiologist. All of them subsequently had conventional cystoscopy, and the results were compared in terms of ureterocele features including anatomy, number, size, location, and extension.

RESULTS

Three-dimensional VSC was well tolerated in all cases without any complication. Image quality was suboptimal in 2 of 16 patients. Out of the remaining 14 cases, VSC had a high accuracy in characterization of the ureterocele features (93%). Only the extension of one ureterocele was not precisely detected by VSC.

CONCLUSIONS

The results of this study suggest three-dimensional sonography as a promising noninvasive diagnostic modality in the evaluation of ectopic ureterocele in children.

Ultrasonographic assessment of the anterolateral ligament of the knee in healthy subjects

Objective

The aim of our study was to determine inter-observer agreement in the ultrasonographic identification of the anterolateral ligament (ALL) and in the evaluation of its length and thickness in healthy subjects.

Methods

80 healthy volunteers (160 knees) (42 males and 38 females) were enrolled in the study. All subjects underwent ultrasound (US) examination of both knees, performed by two physicians with over ten years of musculoskeletal US experience. In order to keep the ALL under optimal tension, the knee was flexed at approximately 30-35°, slightly internally rotated and length and thickness of the ligament were measured.

Results

ALL was identified in 93.8% (150 out of 160) and in 92.5% (148 out of 160) of the knees by Evaluator 1 and Evaluator 2, respectively. Interobserver agreement was substantial to almost perfect for the visualization of the ALL ( =0.90) and for measurements of its length (ICC = 0.83), and strong for measurements of its thickness (ICC = 0.75).

Conclusion

In our study on healthy subjects, ALL has been visualized with a high rate of reproducibility. Further studies are needed to see if US may be a reliable and reproducible diagnostic tool in patients with traumatic or degenerative knee disorders.

Level of evidence

II, evidence obtained from cohort study.

Anterolateral Ligament of the Knee: Anatomy, Function, Imaging, and Treatment

The anterolateral ligament (ALL) of the knee has gained attention recently for its potential role in rotational stability of the knee, especially in association with anterior cruciate ligament (ACL) injuries. Anatomic studies have characterized the ALL as it runs in an anteroinferior and oblique direction from the lateral distal femur to the anterolateral proximal tibia, although the prevalence and variance of this ligament are not well understood. Magnetic resonance imaging and ultrasound have identified the ligament and linked it with the classically described Segond fracture. While the ALL likely plays a role in rotational stability of the knee, further studies investigating the significance of ALL injuries and the role of ALL reconstruction in combination with ACL reconstruction are warranted.

The anterolateral ligament: Anatomic implications for its reconstruction

BACKGROUND

The purpose of this study was to define the best anatomic parameters with which to perform an accurate anterolateral ligament (ALL) reconstruction. These parameters were anatomical insertions, allowing favorable isometry, length variation during flexion, and anthropometric predictors of ALL lengths.

METHODS

A total of 84 fresh-frozen cadaver knees were dissected to analyze the ALL, focusing on its femoral insertion. The ALL length was measured in different degrees of flexion (extension, 30°, 60°, and 90° of flexion) and rotation (neutral, internal or external rotation). The ALL width and thickness were measured. A correlation between ALL length, the general knee size and individual characteristics was investigated.

RESULTS

The ALL was present in 80 specimens (95%). The femoral footprint was always posterior (5.52±0.93 mm, range 3.83-6.94) and slightly proximal (1.51±0.75mm, range 0.63-2.37) to the lateral femoral epicondyle. The mean ALL length increased with internal rotation and decreased with external rotation (P<0.05). The maximum ALL length was found at 30° of flexion, and the minimum at 90°. There was a significant correlation between the ALL length and height, sex, and proximal femur dimensions.

CONCLUSION

In order to get an anatomical reconstruction with favorable isometry, it is recommended that the ALL femoral graft is implanted posterior and slightly proximal to the epicondyle. It is also suggested that the tension be adjusted by fixing the graft between 0 and 30° of flexion, being tighter near extension. This will allow good rotational stability without implying any stiffness.

Ultrasonographic visualization and assessment of the anterolateral ligament

PURPOSE

Injury to the anterolateral ligament (ALL) of the knee has recently received attention as a potential risk factor for failure of anterior cruciate ligament reconstruction. However, evaluation of the anterolateral ligament is currently difficult, and radiologic data are sparse with regard to the normal appearance of this ligament. The purpose of the present study was to determine whether the ALL could be identified and visualized using ultrasonography.

METHODS

Ten non-paired, fresh-frozen cadaveric knees underwent ultrasound by an experienced musculoskeletal radiologist using a Siemens S2000 Acuson Ultrasound machine with a 14-MHz linear transducer. After first identifying anatomical landmarks by palpation, a thin band of tissue originating in the vicinity of the fibular collateral ligament (FCL) origin was identified and followed up distally. The tibia was held at 30° of flexion and internally rotated to verify tightening of the structure. Under ultrasound guidance, 25-gauge hypodermic needles were placed at what were sonographically determined to be the origin and insertion points of the ligament. One-tenth of a CC of aniline blue dye was injected. The specimens were then dissected to confirm the presence and location of the ALL. If an ALL was found, distances between the epicentre of the injected dye and the actual origin and insertion points were calculated. Additionally, ligament length based on dissection images and ultrasound images was calculated.

RESULTS

Eight of ten specimens had an anterolateral structure that originated from the lateral femoral epicondyle just posterior and superior to the origin of the FCL and inserted on the lateral plateau approximately halfway between Gerdy's tubercle and the fibular head. The average length based on ultrasound was 3.8 cm (±.7; range 3.1-4.7) and 4.1 cm (±1.1; range 2.6-6.1) based on dissection. Length based on dissection and ultrasound had minimal agreement (ICC = .308; 95 % confidence interval .257-.382, p = .265). The average width of the structure on dissection was .8 cm (±.24; range .5-1.2). The mean distance from ultrasound-determined origin and insertion points to anatomical origin and insertion based on dissection was 10.9 mm (±2.9, range 7.0-15.8) and 12.5 mm (±5.7 range 3.2-19.3), respectively. Inter-observer reliability was excellent for all measurements based on dissection and ultrasound.

CONCLUSION

Ultrasound was unable to reliably identify the anterolateral structure from its femoral to tibial attachment sites. Distinguishing it from the posterior IT band and anterolateral capsule was challenging, and it is possible that the structure is a thickened band of fascia rather than a true ligament. As a clinical diagnostic tool, ultrasound likely offers little utility in the evaluation of the ALL for injury.

LEVEL OF EVIDENCE

IV.

Anterolateral Ligament Expert Group consensus paper on the management of internal rotation and instability of the anterior cruciate ligament - deficient knee

Purpose of this paper is to provide an overview of the latest research on the anterolateral ligament (ALL) and present the consensus of the ALL Expert Group on the anatomy, radiographic landmarks, biomechanics, clinical and radiographic diagnosis, lesion classification, surgical technique and clinical outcomes. A consensus on controversial subjects surrounding the ALL and anterolateral knee instability has been established based on the opinion of experts, the latest publications on the subject and an exchange of experiences during the ALL Experts Meeting (November 2015, Lyon, France). The ALL is found deep to the iliotibial band. The femoral origin is just posterior and proximal to the lateral epicondyle; the tibial attachment is 21.6 mm posterior to Gerdy's tubercle and 4-10 mm below the tibial joint line. On a lateral radiographic view the femoral origin is located in the postero-inferior quadrant and the tibial attachment is close to the centre of the proximal tibial plateau. Favourable isometry of an ALL reconstruction is seen when the femoral position is proximal and posterior to the lateral epicondyle, with the ALL being tight upon extension and lax upon flexion. The ALL can be visualised on ultrasound, or on T2-weighted coronal MRI scans with proton density fat-suppressed evaluation. The ALL injury is associated with a Segond fracture, and often occurs in conjunction with acute anterior cruciate ligament (ACL) injury. Recognition and repair of the ALL lesions should be considered to improve the control of rotational stability provided by ACL reconstruction. For high-risk patients, a combined ACL and ALL reconstruction improves rotational control and reduces the rate of re-rupture, without increased postoperative complication rates compared to ACL-only reconstruction. In conclusion this paper provides a contemporary consensus on all studied features of the ALL. The findings warrant future research in order to further test these early observations, with the ultimate goal of improving the long-term outcomes of ACL-injured patients. Level of evidence Level V-Expert opinion.

High prevalence of all complex Segond avulsion using ultrasound imaging

PURPOSE

The aim of this study was to determine the prevalence of a Segond avulsion fractures in acute ACL tears with ultrasound and to investigate whether other injuries can predict the avulsion.

MATERIALS AND METHODS

One hundred thirty-eight ultrasound analyses of acute knee trauma were collected and scored for diagnosed injuries. The reports of patients with an ACL tear (N = 87) were evaluated to determine possible increased prevalence of Segond avulsion fracture with ultrasound. The associations between the diagnosed injuries and presence of a Segond avulsion were scored. The sports carried out at the time of injury were evaluated as possible prognostic factor.

RESULTS

In 25/87 (29%) of the patients with an ACL tear, a Segond avulsion was observed in ultrasound. Lateral femoral condyle (LFC) impaction showed the strongest individual association with a Segond avulsion and was the best predicting variable. LFC impaction, sustained during low-risk pivoting sport, shows a stronger association with a Segond avulsion, as compared to LFC impaction sustained during high-risk pivoting sports.

CONCLUSION

Ultrasound shows a higher prevalence of Segond avulsions as literature shows with MRI or radiography. LFC impaction is the best variable in predicting this type of avulsion. Ultrasound examination should be considered, if this fracture was not diagnosed with MRI or radiographic analysis.

LEVEL OF EVIDENCE

IV.

The anterolateral complex in anterior cruciate ligament deficient knees demonstrate sonographic abnormalities on high-resolution sonography

PURPOSE

The presence of anterolateral ligament of the knee is still controversial, and some physicians prefer to call this structure anterolateral complex (ALC) to infer plural nature of structures involved. The purpose of this study was to describe the scanning techniques and to classify various sonographic appearances of the tibial-side ALC of the knee in subjects with anterior cruciate ligament (ACL) injury. It was hypothesized that sonographic abnormity of the ALC would be associated with ACL injury history.

METHODS

Patients with a history of unilateral ACL injury were prospectively recruited, and the ALC was sonographically evaluated. During the evaluation, the lateral femoral epicondyle was visualized in anatomic transverse view first. At this location, the ALC was typically most conspicuous between the short head of the biceps femoris muscle and the posterior and deep aspect of the iliotibial band superficial to the origin of the lateral collateral ligament. The ALC was followed distally to the broad insertion centralizing to the area posterior to Gerdy's tubercle. The appearance of the distal insertion of the ALC was classified based both on echogenicity and on the presence of a Segond fracture as follows: Grade 0: isoechoic to the rest of the ALC, Grade 1: hypoechoic, Grade 2: anechoic, and Grade 3: Segond fracture. The uninjured side was similarly scanned for comparison.

RESULTS

A total of 28 patients (13 men; mean age 22.1 ± 8.1 years old with range: 12-44; mean body mass index 25.0 with range: 18.9-39.2) were included in this study. The average time from injury to sonograhpic evaluation was 4 months (range: 2 days to 1 year). Of 28 ACL-deficient knees, 19 were (68%) graded as Grade 0 in the distal insertion of the ALC, 7 (25%) as Grade 1, 1 (3.5%) as Grade 2, and 1 (3.5%) as Grade 3. Contralateral knees showed 25 knees (89%) with Grade 0 and 3 knees (11%) with Grade 1.

CONCLUSION

ACL injury history was associated with a higher incidence of sonographic abnormalities within the distal insertion of the anterolateral complex.

LEVEL OF EVIDENCE

III.

Identification of the Anterolateral Ligament on Magnetic Resonance Imaging

Studies continue to demonstrate the importance of the anterolateral ligament (ALL) as a secondary restraint in rotational stability of the knee. No clinical exam exists to reliably test the ALL. Advanced imaging allows the surgeon to reliably identify the ALL as an independent structure of the lateral knee. This technique paper provides a reproducible method for identification of the ALL on 3T magnetic resonance imaging based on previously conducted cadaveric dissections of the ligament.

News You Can Use: The Knee Anterolateral Ligament and the ISAKOS Journal

The knee anterolateral ligament may be fiction, but we thought it fact. As true anatomic restoration of the anterior cruciate ligament (ACL) may not be possible today, we are open to the possibility that lateral augmentation of ACL reconstruction could be of benefit in some patients.