Marcio Albers

The anterolateral complex of the knee: a pictorial essay

AbstractInjuries to the anterolateral complex of the knee can result in increased rotatory knee instability. However, to diagnose and treat patients with persistent instability properly, surgeons need to understand the multifactorial genesis as well as the complex anatomy of the anterolateral aspect of the knee in its entirety. While recent research focused primarily on one structure (anterolateral ligament—ALL), the purpose of this pictorial essay is to provide a detailed layer-by-layer description of the anterolateral complex of the knee, consisting of the iliotibial band with its superficial, middle, deep, and capsulo-osseous layer as well as the anterolateral joint capsule. This may help surgeons to not only understand the anatomy of this particular part of the knee, but may also provide guidance when performing extra-articular procedures in patients with rotatory knee instability. Level of evidence V.

The Segond Fracture Is an Avulsion of the Anterolateral Complex.

Background: The Segond fracture was classically described as an avulsion fracture of the anterolateral capsule of the knee. Recently, some authors have attributed its pathogenesis to the “anterolateral ligament” (ALL). Biomechanical studies that have attempted to reproduce this fracture in vitro have reported conflicting findings. Purpose: To determine the anatomic characteristics of the Segond fracture on plain radiographs and magnetic resonance imaging (MRI), to compare this location with the location of the ALL described in prior radiographic and anatomic publications, and to determine the fracture’s attachments to the soft tissue anterolateral structures of the knee. Study Design: Case series; Level of evidence, 4. Methods: A total of 36 anterior cruciate ligament–injured patients with Segond fractures (33 male, 3 female; mean age, 23.2 ± 8.4 years) were enrolled. MRI scans were reviewed to determine the anatomic characteristics of the Segond fracture, including the following: proximal-distal (PD) length, anterior-posterior (AP) width, medial-lateral (ML) width, PD distance to the lateral tibial plateau, AP distance to the Gerdy tubercle (GT), and AP distance from the GT to the posterior aspect of the fibular head. The attachment of the anterolateral structures to the Segond fragment was then categorized as the iliotibial band (ITB) or anterolateral capsule. Interrater reliability of the measurements was determined by calculating the Spearman rank correlation coefficient. MEDLINE, Web of Science, and the Cochrane Library were searched from inception to May 2016 for the following keywords: (1) “Segond fracture,” (2) “anterolateral ligament,” (3) “knee avulsion,” (4) “lateral tibia avulsion,” and (5) “tibial plateau avulsion.” All studies describing the anatomic location of the Segond fracture and the ALL were included in the systematic review. Results: On plain radiographs, the mean distance of the midpoint of the fracture to the lateral tibial plateau was 4.6 ± 2.2 mm. The avulsed fracture had a mean PD length of 9.2 ± 2.5 mm and a mean ML width of 2.4 ± 1.4 mm. On MRI, the mean distance of the proximal fracture to the tibial plateau was 3.4 ± 1.6 mm. The mean PD length was 8.7 ± 2.2 mm, while the mean AP width was 11.1 ± 2.2 mm. The mean distance between the GT and the center of the fracture was 26.9 ± 3.3 mm, while the mean distance between the GT and the posterior fibular head was 53.9 ± 4.4 mm. The mean distance of the midpoint of the fracture to the tibial plateau was 7.8 ± 2.7 mm, while the center of the fracture was 49.9% of the distance between the GT and the posterior aspect of the fibular head. Analysis of soft tissue structures attached to the fragment revealed that the ITB attached in 34 of 36 patients and the capsule attached in 34 of 36 patients. One patient had only the capsule attached, another had only the ITB attached, and the last showed neither clearly attached. A literature review of 20 included studies revealed no difference between the previously described Segond fracture location and the tibial insertion of the ALL. Conclusion: The results of this study confirmed that while the Segond fracture occurs at the location of the tibial insertion of the ALL, as reported in the literature, MRI was unable to identify any distinct ligamentous attachment. MRI analysis revealed that soft tissue attachments to the Segond fracture were the posterior fibers of the ITB and the lateral capsule in 94% of patients.

Gross, Arthroscopic, and Radiographic Anatomies of the Anterior Cruciate Ligament: Foundations for Anterior Cruciate Ligament Surgery

The anterior cruciate ligament (ACL) is one of the more studied structures in the knee joint. It is not a tubular structure, but is much narrower in its midsubstance and broader at its ends, producing an hourglass shape. The ACL is composed of 2 functional bundles, the anteromedial and posterolateral bundles, that are named for their location of insertion on the anterior surface of the tibial plateau. Although the relative contribution in terms of total cross-sectional area of the ACL has been noted to be equal in regards to each bundle, dynamically these bundles demonstrate different properties for knee function.

Anatomic and Histological Investigation of the Anterolateral Capsular Complex in the Fetal Knee

Background: There is currently disagreement with regard to the presence of a distinct ligament in the anterolateral capsular complex of the knee and its role in the pivot-shift mechanism and rotatory laxity of the knee. Purpose: To investigate the anatomic and histological properties of the anterolateral capsular complex of the fetal knee to determine whether there exists a distinct ligamentous structure running from the lateral femoral epicondyle inserting into the anterolateral tibia. Study Design: Descriptive laboratory study. Methods: Twenty-one unpaired, fresh fetal lower limbs, gestational age 18 to 22 weeks, were used for anatomic investigation. Two experienced orthopaedic surgeons performed the anatomic dissection using loupes (magnification ×3.5). Attention was focused on the anterolateral and lateral structures of the knee. After the skin and superficial fascia were removed, the iliotibial band was carefully separated from underlying structures. The anterolateral capsule was then examined under internal and external rotation and varus-valgus manual loading and at different knee flexion angles for the presence of any ligamentous structures. Eight additional unpaired, fetal lower limbs, gestational age 11 to 23 weeks, were used for histological analysis. Results: This study was not able to prove the presence of a distinct capsular or extracapsular ligamentous structure in the anterolateral capsular complex area. The presence of the fibular collateral ligament, a distal attachment of the biceps femoris, the entire lateral capsule, the iliotibial band, and the popliteus tendon in the anterolateral and lateral area of the knee was confirmed in all the samples. Histological analysis of the anterolateral capsule revealed a loose, hypocellular connective tissue with less organized collagen fibers compared with ligament and tendinous structures. Conclusion: The main finding of this study was that the presence of a distinct ligamentous structure in the anterolateral complex is not supported from a developmental point of view, while all other anatomic structures were present. Clinical Relevance: The inability to prove the existence of a distinct ligamentous structure, called the anterolateral ligament, in the anterolateral knee capsule may indicate that the other components of the anterolateral complex, such as the lateral capsule, the iliotibial band, and its capsule-osseous layer, are more important for knee rotatory stability.

How Can MRI Help with Decision-Making?

Football athletes are subjected to a myriad of injuries inherent to this dynamic, fast-paced sport. Being the most widely played sport in the world, orthopedic surgeons frequently encounter common injuries to footballers. Anterior cruciate ligament (ACL) tears are potentially severe injuries that may threaten the career of these athletes. It may affect players from all ages, from recreational weekend athlete to world-class professional players. The interaction between cleats and the play surface, opponent contact, individual characteristics, and style of play all play a role in the occurrence of ACL tears. Its treatment, however, can be divided in two major categories: operative and non-operative. Although ACL reconstruction is considered by many as the gold-standard treatment for patients who want to return to football, there are situations when non-operative treatment may suffice. The decision of the appropriate timing to return to play is subject of much attention and discussion, and graft tears are daunting injuries that may jeopardize an athlete’s career. There is increasing interest to drive the scientific decision-making process that would aid doctors, athletic trainers, agents, managers, and footballers to tailor the rehabilitation process to each athlete, allowing return to pre-injury level of play. Magnetic resonance imaging (MRI) may provide invaluable information in assessing the healing and maturation process of reconstructed ACL graft. It is a noninvasive tool which may provide insight into the biomechanical properties of the graft itself. This chapter will explore the best available scientific evidence in using MRI to assess ACL healing and graft maturation during rehabilitation, as an additional tool to guide ACL-injured footballers to safely return to competition.

Individualized Anterior Cruciate Ligament Graft Matching: In Vivo Comparison of Cross-sectional Areas of Hamstring, Patellar, and Quadriceps Tendon Grafts and ACL Insertion Area:

Background: Recent literature correlated anterior cruciate ligament (ACL) reconstruction failure to smaller diameter of the harvested hamstring (HS) autograft. However, this approach may be a simplification, as relation of graft size to native ACL size is not typically assessed and oversized grafts may impart their own complications. Purpose: To evaluate in vivo data to determine if the commonly used autografts reliably restore native ACL size. Study Design: Descriptive laboratory study. Methods: Intraoperative data of the tibial insertion area and HS graft diameter were collected and retrospectively evaluated for 46 patients who underwent ACL reconstruction with HS autografts. Magnetic resonance imaging measurements of the cross-sectional area (CSA) of the possible patellar tendon (PT) and quadriceps tendon (QT) autografts were also done for each patient. The percentages of tibial insertion site area restored by the 3 possible grafts were then calculated and compared for each individual. Results: The mean ACL tibial insertion area was 107.2 mm2 (60.5-155.5 mm2). The mean CSAs of PT, HS, and QT were 33.2, 55.3, and 71.4 mm2, respectively. When all grafts were evaluated, the percentage reconstruction of the insertion area varied from 16.2% to 123.1% on the tibial site and from 25.5% to 176.7% on the femoral site, differing significantly for each graft type (P < .05). On average, 32.8% of the tibial insertion area would have been filled with PT, 53.6% by HS, and 69.5% by QT. Based on previous cadaveric studies indicating that graft size goal should be 50.2% ± 15% of the tibial insertion area, 82.7% of patients in the HS group were within this range (36.9%, QT; 30.5%, PT), while 65.2% in the PT group were below it and 60.9% in the QT group were above it. Conclusion: ACL insertion size and the CSAs of 3 commonly used grafts vary greatly for each patient and are not correlated with one another. Thus, if the reconstructed ACL size is determined by the harvested autograft size alone, native ACL size may not be adequately restored. PT grafts tended to undersize the native ACL, while QT might oversize it. Clinical Relevance: These results may help surgeons in preoperative planning, as magnetic resonance imaging measurements can be helpful in determining individualized graft choice to adequately restore the native ACL.

Bone Bruise Patterns in Skeletally Immature Patients With Anterior Cruciate Ligament Injury: Shock-Absorbing Function of the Physis:

Background: Bone bruises are frequently found on magnetic resonance imaging (MRI) after anterior cruciate ligament (ACL) injury and have been related to the force associated with the trauma. Yet, little is known about the bone bruise distribution pattern of skeletally immature (SI) patients, as the presence of an open physis may play a role in energy dissipation given its unique structure. Purpose: To describe and compare the location and distribution of tibial and femoral bone bruises, observed on MRI, between 2 groups of ACL-injured knees: the first group with an open physis and the second with a closed physis. Additionally, based on the bone bruise distribution pattern, the secondary aim of the study was to propose a new classification of bone bruise in SI patients. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective review was conducted to identify all cases of primary ACL tears in patients ≤16 years old, with MRI within 6 weeks of injury between January 2012 and December 2016. Overall, 106 patients were identified: 53 with open physis (skeletally immature [SI] group) and 53 with closed physis as control (skeletally mature [SM] group). MRI scans were reviewed to assess for the presence and location of bone bruises. Longitudinal bone bruise distribution was described as epiphyseal and metaphyseal in both femur and tibia. The proposed classification for tibia and femur has 2 parts: the location of the bone bruise in the (I) lateral, (II) medial, or (III) medial and lateral parts of the bone; and if the bone bruise (a) does not or (b) does cross the physis. For the tibia, if the bone bruise is also present in the central portion, a letter C is added. Results: The SI group had significantly fewer bone bruises cross the physis and extend into the metaphysis than did the SM group for both the tibia (25% vs 85%, respectively; P < .0001) and the femur (4% vs 42%; P < .0001). The most common patterns observed in the SI group were type IIICa in the tibia (medial/lateral and central, not extending into the metaphysis: 42%) and type Ia in the femur (lateral, not extending into the metaphysis: 59%). Conclusion: The data from this study shows that patients with an open physis at the occurrence of an acute ACL rupture have unique bone bruise patterns as compared with those with a closed physis. In the SI patients, the bone bruise pattern is significantly less frequently observed in the tibial and femoral metaphysis.

Laparoscopic Treatment of Pubic Symphysis Instability With Anchors and Tape Suture

Patients with pubic symphysis instability who had failed nonoperative treatments may benefit from surgical repair. This disease process is rare, most commonly seen in postpartum women and athletes, and its surgical treatment is invasive and nonphysiological. Currently described surgical interventions, although limited, include plating, which provides an overly rigid construct with the risk of failure and possibly poor long-term outcomes particularly in athletes, and treatments such as curettage, more commonly used in the treatment of osteitis pubis. An emerging option is minimally invasive laparoscopic fixation using knotless anchors with a tape suture in a crisscross configuration. This possibly allows more physiological movement of the pubic symphysis in a less invasive manner. A detailed technical description and discussion of the technique are provided.