Anterior Oblique Ligament Research Articles

The multidirectional roles of the anterior oblique ligament and dorsoradial ligament of the thumb carpometacarpal joint.

The multidirectional biomechanics of the thumb carpometacarpal (CMC) joint underlie the remarkable power and precision of the thumb. Because of the unconfined nature of thumb CMC articulation, these biomechanics are largely dictated by ligaments, notably the anterior oblique ligament (AOL) and the dorsoradial ligament (DRL). However, the rotational and translational stabilizing roles of these ligaments remain unclear, as evidenced by the variety of interventions employed to treat altered pathological CMC biomechanics. The purpose of this study was to determine the effects of sectioning the AOL (n = 8) or DRL (n = 8) on thumb CMC joint biomechanics (rotational range-of-motion [ROM] and stiffness, translational ROM) in 26 rotational directions, including internal and external rotation, and in eight translational directions. Using a robotic musculoskeletal simulation system, the first metacarpal of each specimen (n = 16) was rotated and translated with respect to the trapezium to determine biomechanics before and after ligament sectioning. We observed the greatest increase in rotational ROM and decrease in rotational stiffness in flexion directions and internal rotation following DRL transection and in extension directions following AOL transection. The greatest increase in translational ROM was in dorsal and radial directions following DRL transection and in volar directions following AOL transection. These data suggest the AOL and DRL play complementary stabilizing roles, primarily restraining translations in the direction of and rotations away from the ligament insertion sites. These findings may inform future interventions or implant designs for pathological CMC joints.

A Novel Ligamentous Complex in the Anteromedial Region of the Knee: A Cadaveric Study.

The medial knee structures have a primary role in stabilizing valgus and rotational stress, which makes them important in assessing the ligament-injured knee globally and choosing the most adequate treatment. To conduct a layer-by-layer dissection of the knee's anteromedial side and provide a qualitative and quantitative description of the anatomy and histology of a ligament in the anteromedial region of the knee, which we have termed the anterior oblique ligament (AOL). Also, to describe the AOL relationship with what we have termed the medial cross-a ligament complex that stabilizes the medial pivot. Descriptive laboratory study. A total of 35 fresh-frozen knees from transfemoral amputations that were exclusively performed for vascular reasons were dissected. Structures were identified after meticulous dissection, respecting the same protocol, measured with a digital caliper rule, and histologically studied for data. The AOL was found in all dissected knees, with a mean length of 31.47 ± 5.06 mm. This structure presented a ligament histology with densely organized collagen fibrils. The medial cross was represented by the superficial medial collateral ligament, AOL (anterior region), and posterior oblique ligament. This study demonstrated the presence of a ligament in the anteromedial region of the knee, termed the AOL. This structure was in the anterior part of a ligament complex-the medial cross. Studying and revisiting the medial compartment can provide important information for understanding joint instability and promoting better results in ligament reconstructions.

Biomechanical Comparison of Stability and Strength After Ulnar Collateral Ligament Reconstruction With Suture Anchor Fixation Versus Bone Tunnels.

Ulnar collateral ligament (UCL) injuries occur frequently in baseball players, and UCL reconstruction is performed when nonoperative treatment fails. To compare a novel all-suture anchor method of UCL reconstruction with a method using bone tunnels (Ito method) by investigating the displacement against valgus torque and the failure strength. Controlled laboratory study. Eight fresh-frozen cadaveric upper extremities (mean age, 82.0 years) were utilized in this study. To evaluate the displacement against valgus torque, the valgus stability test was performed for 4 anterior oblique ligament (AOL) conditions: intact AOL, resected AOL, reconstructed using the anchor method, and reconstructed using the Ito method. The load-to-failure test was performed to evaluate the failure strength of the anchor and Ito methods. Displacement against valgus load was compared between conditions using the repeated-measures 2-way analysis of variance with Bonferroni post hoc test, and failure strength between the anchor and Ito methods was compared using the unpaired t test. Displacements of the intact AOL and anchor method were significantly greater than those of the resected AOL at both 60° and 90° of flexion (intact AOL: P = .005 and P < .001, respectively; and anchor method: P = .024 and P < .001, respectively). The displacement of the Ito method at 90° of flexion was significantly greater than that of the resected AOL (P = .003), but no significant difference was observed at 60° of flexion (P = .109). There were no significant differences in displacement between the anchor and Ito methods at any flexion angle, nor was there a significant difference in failure torque between the anchor and Ito methods (16.3 ± 3.1 vs 17.6 ± 2.3 N·m, respectively; P = .537). The displacement and failure strength against a valgus load after UCL reconstruction using a suture anchor on the ulnar side were equal to those using bone tunnels. UCL reconstruction using a suture anchor on the ulnar side is simpler and less invasive than using bone tunnels, with similar outcomes.

Magnetic resonance imaging of the knee anteromedial quadrant

ObjectiveThis study aims to evaluate the possibility of characterizing an extra-articular thickening in the knee anteromedial quadrant in routine MRI scans.Materials and methodsFirstly, in a pilot study, for a better understanding of this extra-articular thickening trajectory in MRI, polytetrafluoroethylene (PTFE) tubes were attached to the ligament structure topography in two dissected pieces. Afterward, 100 knee MRI studies were randomly selected from our database, and 97 met the inclusion criteria. Two musculoskeletal radiologists interpreted the exams separately. Both had previously studied the ligament in the cadaveric knee MRI with the PTFE tube.ResultsThe intraobserver and interobserver agreement for the ligament identification was calculated using Cohen’s Kappa coefficient. The first radiologist identified the structure in 41 of the 97 scans (42.2%), and the second radiologist in 38 scans (39.2%). The interobserver agreement was substantial, with a Kappa of 0.68 and an agreement of 84.5%. The results suggest that this extra-articular thickening, recently called Anterior Oblique Ligament (AOL) in the literature, is a structure that can be frequently visualized on MRI scans with a high level of interobserver agreement in a relatively large number of exams.ConclusionTherefore, this study indicates that MRI is a promising method for evaluating this anteromedial thickening, and it may be used for future studies of the Anterior Oblique Ligament.

Anterior Cruciate and Anterior Oblique Ligament Reconstruction Using Hamstrings and Peroneus Longus’ Anterior Half Grafts

Anterior cruciate ligament injuries are common in high school and college with an estimated 120,000 cases per year in the United States. Most sports injuries occur without direct contact, and knee valgus with external rotation of the foot is the most common movement. This movement may be related to the injury of the anterior oblique ligament located in the anteromedial quadrant of the knee. This technical note presents anterior cruciate ligament reconstruction with extraarticular anteromedial reinforcement using hamstring and the anterior half of the peroneus longus grafts.

Investigating the contribution of the dorsal radial ligamentand the anterior obliqueligament to the stability of the trapeziometacarpal joint

Objectives: Investigate the contribution of the dorsal radial ligament (DRL) and the anterior oblique ligament (AOL) to the stability of the trapeziometacarpal joint (TMCJ). Subjects and methods: Cross-sectional descriptive study was conducted on thirty fresh frozen cadaveric hands at the Anatomy Department, University of Medicine and Pharmacy at Ho Chi Minh City. The dimensions of AOL and DRL were measured after dissection. The force-displacement system was adhered to the TMCJ, exerted the force in the direction of the thumb flexion, extension, abduction, adduction, and recorded the translation of the joint. Then either AOL or DRL was transected randomly and compared the translation of the stated directions. Results: Average age was 72.93±13.79. The dimensions of length, width, and thickness of AOL were 9.390±0.427 mm, 4.613±0.278 mm, and 1.011±0.083 mm, respectively; and of DRL were 9.726±0.383 mm, 5.047±0.304 mm, 1.812±0.145 mm. The transection of DRL resulted in more translation of TMCJ in direction of flexion, abduction, and adduction than the transection of AOL. Conclusions: DRL is significantly longer, wider and thicker than AOL (p&lt;0.01).DRL is more important than AOL in providing stability to the trapeziometacarpal joint. However, AOL has a certain role in the stability of the trapeziometacarpal joint.

Anatomical 3 Ligaments Reconstruction for Symptomatic Thumb Carpometacarpal Joint Instability.

Thumb carpometacarpal (CMC) joint instability is thought to be a debilitating disorder and, if left untreated, develops joint persistent synovitis and osteoarthritis. In this study, we report a novel surgical technique reconstructing the anterior oblique ligament, the dorsoradial ligament, and the intermetacarpal ligament simultaneously using both the transverse carpal ligament, and the palmaris longus tendon. Six patients with a mean age of 44 years showing no osteoarthritic changes by the radiographical examination underwent our anatomical three ligaments reconstruction for persistent painful thumb CMC joint instability. Clinical results with the mean follow-up of 20 months demonstrated that the pain was subjectively improved in all patients, both the grip and the pinch strength were increased significantly and good functional motion of the thumb could be observed after the operation. These findings indicated that our surgical procedure could be one option of treatment of the symptomatic CMC joint instability in early-stage arthritis.

Carpometacarpal Ligament Reconstruction, Surgical Technique and Outcomes.

Basal thumb arthritis is a common condition with the earliest stage described as a period of ligament laxity and joint instability, without radiographic signs of arthritis. The condition is usually managed conservatively but a number of individuals can present with persistence of symptoms. We would like to describe our preferred technique for the management carpometacarpal ligament instability and laxity. This technique utilizes a slip of the flexor carpi radialis tendon and offers reconstruction of the intermetacarpal, dorsoradial and anterior oblique ligaments in an anatomic fashion using standard instruments available. The author has performed this technique in 33 patients over a course of 10 years and long-term outcomes of these cases are presented in this paper.

Thumb carpometacarpal joint soft-tissue lesions in an asymptomatic population. An MRI study

The purpose of this study was to evaluate the prevalence of ligament pathology around the first carpometacarpal joint in an asymptomatic population. We used a compact office-based MRI system and examined the hands of 117 healthy volunteers. We checked the competence of the anterior oblique ligament and of the posterior ligament complex on the MRI images. Our results showed that, in 82% of the study population, both ligaments could be perfectly visualized, with consistent signal from origin to insertion. Examination found signal changes indicating a damaged or torn ligament in the other cases. This study suggests that ligament pathology seen on MRI should be interpreted with caution. In symptomatic patients, pathologic images are to be interpreted in the light of the relevant clinical context. Level of evidenceIII

In Vivo Assessment of Stiffness of Anterior Oblique Bundle of Ulnar Collateral Ligament Using Ultrasound Elastography

The Anterior oblique ligament (AOL) of the ulnar collateral ligament (UCL) attaches to the inferior aspect of the medial epicondyle of the humerus and the coronoid process of the ulna, and has an important role in life and exercise by inhibiting flexion and valgus of the elbow. Understanding the mechanical function of the UCL in vivo is important for the diagnosis and prevention of elbow injuries caused by baseball and other sports. In this study, we aimed to measure the stiffness of the AOL during changes in elbow flexion angle and pronation and supination using ultrasound elastography. The stiffness of the AOL decreased with increasing elbow flexion angle in all conditions, and was less affected by pronation and supination compared to the intermediate position at the same elbow flexion angle.

Knee anteromedial compartment dissection: Final results and anterior oblique ligament description.

The anteromedial region of the knee is little explored in the literature and may play an important role in anteromedial rotatory instability. The purpose of this study is to describe a ligamentous structure in the anteromedial region of the knee identified in a series of anatomical dissections of cadaveric specimens. Twenty-one cadaveric knees were dissected to study the medial compartment. Exclusion criteria were signs of trauma, previous surgery, signs of osteoarthritis, and poor preservation state. The main structures of this region were identified during medial dissection. After releasing the superficial medial collateral ligamentof the tibia, the anterior oblique ligament (AOL)was isolated. The morphology of the structure and its relationship with known anatomical parameters were determined. For the statistical analysis, the means and standard deviations were calculated for continuous variables. A 95% confidence interval was defined as significant. Student's t-tests were used for continuous variables. After dissection, a distinct ligamentous structure (AOL) was found in the medial region of the knee. This structure was found in 100% of the cases, was located extracapsularly and originated in the anterior aspect of the medial epicondyle, running obliquely toward the tibia. When crossing the joint, the ligament presented a fan-shaped opening, exhibiting a larger area at the tibial insertion. The AOL had a mean thickness of 6.83 ± 1.51 mm at its femoral origin and 13.39 ± 2.64 at its tibial insertion. It had a significantly (p = 0.0001) longer mean length with the knee at 90° of flexion (35.27 ± 6.59 mm) than with the knee in total extension (27.89 ± 5.46 mm), indicating that the ligament is tensioned in flexion. A new structure was identified in the anteromedial compartment of the knee with a ligamentous appearance. Further studies are necessary to identify its importance on knee stability. This study demonstrates the anatomy of a new medial structure of the knee. As a result, there will be a better understanding of the stability of the knee.

Ligamentous constraint of the first carpometacarpal joint

To examine the role of the ligaments in maintaining stability of the first carpometacarpal (CMC) joint, a sequential ligament sectioning study of sixteen specimens was performed. While a small compressive force was maintained, loads were applied to displace each specimen in four directions – volar, dorsal, radial, and ulnar. Translations of the specimen in both dorsal-volar and radial-ulnar axes were measured. Initially, the tests were conducted with the specimen intact. These tests were then repeated following sectioning of the CMC anterior oblique ligament (AOL), ulnar collateral ligament (UCL), intermetacarpal ligament (IML) and dorsal radial ligament (DRL). The first CMC joint translation was increased in the absence of IML and DRL (p < 0.05). Both IML and DRL were important in constraining the first CMC joint translation against external applied loads. Potential applications of these findings include the treatment of joint hypermobility and the reduction or delay of onset or progression of first CMC joint osteoarthritis.

Morphological study of mechanoreceptors in ligaments of the trapeziometacarpal joint

The complex stability of the trapeziometacarpal (TMC) joint depends on the role of ligaments and muscles around joints. The mechanoreceptors within ligaments and adequate regulation of peripheral neuromuscle reflexes promote joint dynamic stability. We know that the dorsal radial ligaments (DRL) and anterior oblique ligaments (AOL) play most respective roles of in controlling the stability of the TMC joint. This experiment has the following purposes (1) we want to describe the shape and distribution of mechanoreceptors in DRL and AOL of TMC joint using modified gold chloride staining techniques. (2) To explore whether there is a relationship between gender and the number of mechanoreceptors. Normal specimens of the thumb ligament were obtained from the upper limbs of 12 fresh frozen cadavers. The length, width and thickness of the DRL and AOL were measured. The DRLs and the AOLs were divided into the proximal, middle and distal sections. Each segments of ligament were made into 5 μm thick slices. The slices were stained by modified gold chlorine staining techniques after the slices were dehydrated with 70% alcohol. All the four typical types of nerve endings (the Ruffini corpuscles, Pacinian corpuscles, Golgi corpuscles, and free nerve endings) were found in these ligaments. Pacinian corpuscles were the predominant in all four complexes. Most mechanoreceptors were found in synovial membrane near both ends of the ligaments attached to the bone. The DRL was significantly thicker and tougher than the AOL. The DRL had significantly more mechanoreceptors than AOL. There were significant differences in terms of the number of whole mechanoreceptors in the DRL and the AOL due to the differences of gender. The morphology and distribution of mechanoreceptors are different from those reported in previous literature, suggesting that TMC joint have more complex proprioceptive functions. The proprioception of TMC joint in male maybe more powerful than female.

Role of the transverse ligament of the ulnar collateral ligament of the elbow: a biomechanical study.

BackgroundThe ulnar collateral ligament (UCL) complex of the elbow plays a primary role in valgus and posteromedial stability of the elbow. The anterior oblique ligament (AOL) of the UCL is believed to provide the majority of resistance to external forces on the medial elbow. The transverse ligament (TL) of the UCL is generally thought to have minimal contribution to the elbow’s overall stability. However, recent studies have suggested a more significant role for the TL. The primary aim of this study was to identify the TL’s contribution to the stability of the elbow joint in determining the joint stiffness and neutral zone variation in internal rotation.MethodsTwelve cadaveric elbows, set at a 90° flexion angle, were tested by applying an internal rotational force on the humerus to generate a medial opening torque at the level of the elbow. The specimens were preconditioned with 10 cycles of humeral internal rotation with sinusoidal torque ranging from 0 to 5 Nm. Elbow stiffness measures and joint neutral zone were first evaluated in its integrity during a final ramp loading. The test was subsequently repeated after cutting the TL at 33%, 66%, and 100% followed by the AOL in the same fashion.ResultsThe native UCL complex joint stiffness to internal rotation measured 1.52 ± 0.51 Nm/°. The first observable change occurred with 33% sectioning of the AOL, with further sectioning of the AOL minimizing the joint stiffness to 1.26 ± 0.32 Nm/° (P = .004). A 33% resection of the TL found an initial neutral zone variation of 0.376 ± 0.23° that increased to 0.771 ± 0.41° (P < .01) at full resection. These values were marginal when compared with the full resection of the AOL for which we have found 3.69 ± 1.65° (P < .01).ConclusionThe TL had no contribution to internal rotation elbow joint stiffness at a flexion angle of 90°. However, sequential sectioning of the TL was found to significantly increase the joint neutral zone when compared with the native cadaveric elbow at a flexion angle of 90°. This provides evidence toward the TL having some form of contribution to the elbow’s overall stability.

Risk factors for throwing elbow injuries during pitching analyzed by simulation using human musculoskeletal model in youth baseball pitchers

Pitching mechanics are believed to be risk factors for throwing elbow injury. Thus, a prospective study of abnormal mechanics in youth baseball players is needed. This study aimed to analyze the ulnar collateral ligament during normal pitching using SIMM (Software for Interactive Musculoskeletal Modeling) for analysis and investigate the risk parameters of throwing elbow injuries in youth baseball players. We hypothesized that excessive ulnar collateral ligament force during pitching would be a risk factor for throwing elbow injuries in this population. In this cohort study, youth baseball pitchers (aged 9-11 years) were instructed to throw a ball into a netted target. Using a SIMM musculoskeletal model, we analyzed the force of the anterior band of the anterior oblique ligament, posterior band of the anterior oblique ligament (AOL_PB), and elbow varus moment during pitching (foot contact to ball release). We calculated the integral of each force of the anterior band of the anterior oblique ligament and AOL_PB during pitching and summarized these data to establish an impulse at the medial epicondyle. Each participant was followed up for 12 months to assess the occurrence of throwing elbow injury. During the 12-month follow-up period, 18 pitchers (28.1%) reported throwing elbow injuries in the throwing arm. The results of this study showed that the maximum AOL_PB force and the impulse at the medial epicondyle were risk factors for throwing elbow injuries. The maximum AOL_PB force was significantly higher in the throwing elbow injury group than in the uninjured group (59.4 ± 17.8 N vs. 47.1 ± 17.5 N, P = .014). The impulse at the medial epicondyle was also significantly different (11.1 ± 4.0 N ･ s in the throwing elbow injury group vs. 8.3 ± 4.4 N ･ s in the uninjured group, P = .025). Increasing the AOL_PB force or the impulse at the medial epicondyle may increase the risk of throwing elbow injuries in youth baseball pitchers. It may be possible to reduce injury risk by focusing on ways to decrease AOL_PB load and cumulative stress on the medial epicondyle throughout the throwing motion while still maintaining high levels of ball velocity.

Tissue elasticity of the anterior oblique ligament of the ulnar collateral ligament during contraction of the flexor digitorum superficialis in shear-wave elastography

Tissue elasticity of the anterior oblique ligament of the ulnar collateral ligament during contraction of the flexor digitorum superficialis in shear-wave elastography

The origin structure of each finger in the flexor digitorum superficialis muscle.

The flexor digitorum superficialis muscle (FDS) is considered the most important of the forearm flexors for maintaining elbow valgus stability. However, the relationships between the origin structure of each finger ofthe FDS and the anterior oblique ligament (AOL) of the ulnar collateral ligament and the common tendon (CT) in the proximal part, and morphological features are unclear. The purpose of this study was to clarify the relationships between the origin structure of each finger of the FDS and the AOL and the CT, as well as to clarify the morphological features of the muscle belly of each finger of the FDS. This study examined 20 elbows. The origin of each finger was examined. Muscle mass, muscle fiber bundle length, and the pennation angle of each finger were also measured. In all cases, the third and fourth digits originated from the radius, the anterior common tendon (ACT), and the posterior common tendon (PCT). The second and fifth digits (18 elbows) or an independent fifth digit (2 elbows) originated from the ACT, the PCT, the AOL, and other soft tissues of the elbow. Muscle mass and muscle fiber bundle length in the muscle belly of the third and fourth digits were significantly heavier and longer, respectively, than in the muscle belly of the second and fifth digits. Because the second and fifth digits or an independent fifth digit originated from the AOL, their contraction may cause tension in the AOL.

Evaluation of anterior oblique ligament tension at the elbow joint angle—a cadaver study

The ulnar collateral ligament complex, particularly the anterior oblique ligament (AOL), is mainly a static stabilizer controlling valgus. Various studies have been conducted on the kinematics of elbow joints after ligament cutting; however, no biomechanical studies have measured the tension applied to the ligament. Finite element modeling (FEM) is a very useful tool for biomechanical evaluation of the elbow. However, an accurate FEM of elbow joints cannot be developed without information on the potential tension of ligaments applied during the flexion and extension of elbow joints. We believe that FEM of the elbow joint could be obtained by measuring the material properties and potential tension of the ligament applied during the flexion and extension of the elbow joint. This study aimed to measure the potential tension and material properties of the ligament during the flexion and extension of the elbow, by identifying the relation between ligament length and tension using mechanical testing. We included 10 elbows harvested from 7 fresh-frozen cadavers. The average age of the cadavers was 83.7 ± 5.65 years, and the samples included 8 elbows from 6 male cadavers and 2 elbows from 1 female cadaver. We measured the ligament length at each elbow angle by changing the elbow joint from 0° to 120° in 15° intervals. Thereafter, we extracted the AOL and divided into an anterior band (AB) and a posterior band (PB)and performed a mechanical test to calculate ligament stress. The ligament length of the AB gradually decreased as the flexion angle increased. Conversely, the ligament length of the PB gradually increased as the flexion angle increased. AB and PB lengths were approximately the same between 60° and 75°. The average ligament tension and stress of the AB gradually increased with elbow extension. In contrast, the average ligament tension and stress of the PB gradually increased with elbow flexion. The tension and stress of the AB and PB were balanced around the elbow joint at 60°. The AB was tenser on elbow extension, and the PB was tenser following elbow flexion. Also, the angle at which the AOL stress was equalized was 60°, suggesting that ∼60° is the angle at which the AOL is unlikely to be damaged.

The Effect of the Joint Capsule and Anterior Oblique Ligament on Dorsal Subluxation of the First Metacarpal During Key Pinch.

Laxity of the anterior oblique ligament (AOL) and/or the dorsoradial ligament (DRL) are believed to contribute to the progression of osteoarthritis in the trapeziometacarpal joint through increased dorsal subluxation. Stress radiographs during functional tasks, such as key pinch, can be used to evaluate such joint instability. Cadaveric experiments can explore joint contact pressures as well as subluxation under varying conditions, to gain knowledge about joint mechanics. The disturbance of supporting tissues, such as the joint capsule, during experiments may affect the recorded stability of the joint. To evaluate potential effects of opening the joint capsule and severing the AOL, eleven cadaveric specimens were rigged to simulate key pinch. An anteroposterior (AP) radiograph of the hand was recorded for each specimen while intact, after partially opening the joint capsule and after sectioning the AOL. First metacarpal subluxation levels were compared between the intact joint, partially open joint capsule, and sectioned AOL. Neither opening the joint capsule nor cutting the AOL had a statistically significant effect on metacarpal subluxation. The results indicate that partially opening the joint capsule has a negligible effect on joint mechanics and support recent studies that postulate that the AOL plays a less substantial role in preventing subluxation.

Ultrasound of Normal and Injured Ligaments and Retinacula of the Hand.

Clinical diagnosis of ligament and retinacular injuries of the hand may be challenging. Ultrasound (US) enables detailed high-resolution, dynamic, and real-time evaluation of these structures. This article is a comprehensive review of the intricate anatomy, optimal imaging technique, and normal US appearances of these ligaments and retinacula. The US features, pertinent biomechanics, clinical presentation, and differential diagnosis of injuries affecting the annular pulleys, differentiating from climber's finger; extensor hood including sagittal band and central slip rupture; proximal interphalangeal and metacarpophalangeal collateral ligaments including the Stener lesion and associated volar plate injury; and the anterior oblique or beak ligament of the trapeziometacarpal joint are reviewed. Emphasis is placed on optimal transducer positioning, value of dynamic US, injury severity, surgical indications, and other US findings with important management implications. US facilitates a timely accurate diagnosis of hand ligament and retinacular injury to ensure optimal patient management and minimize the risk of functional impairment of the hand.