Anatomical considerations and clinical implications of bicipital aponeurosis: A magnetic resonance imaging study.

The bicipital aponeurosis (BA) is the distal aponeurosis of the biceps brachii which usually covers the median nerve (MN), and the brachial artery (BrA) and sometimes causes compression of these structures. Since these situations are rarely reported in the literature, BA frequently does not come to mind as a cause of such compression. Therefore, the diagnosis may be delayed. In this study, we aimed to investigate the morphometry of BA and its relationship with the surrounding neurovascular structures and to draw attention to BA as a structure that can cause entrapment of the MN and rarely, the BrA. We examined the MRIs of the elbow of 279 patients (107 women, 172 men) aged between 18 and 72 years. We measured the thickness, length and width of BA, and investigated the anatomical relationship between BA, BrA, and MN. The respective median thickness, width, and length of BA were 0.7 (0.4-1.8 mm), 18.0 (6.0-34.0 mm), and 32.0 (18.0-50.0 mm), respectively. In all sections examined, the BA covered the BrA and MN, and was located immediately anterior to the BrA. In 225 (80.6%) of 279 MRIs, the BrA was located anterior to the MN and posterior to the BA. In the remaining 54 (19.4%) MRIs, the MN was located anterior to the BrA and posterior to the BA. The respective median thickness, width, and length of the BA were 0.7 mm, 18.0 mm, and 32.0 mm, respectively. It covered the BrA and MN and was located immediately anterior to the BrA. The BA sometimes causes compression syndromes of these structures, therefore, for physicians, it is important to understand the anatomy of the BA.

Effect of lacertus fibrosus release on perineural pressure of the median nerve at the elbow: a cadaveric study.

PURPOSE: The lacertus fibrosus (or bicipital aponeurosis) is a potential site of proximal median neuropathy at the elbow. Lacertus syndrome with motor and/or sensory symptoms has been addressed with a minimally invasive surgical lacertus release. This study evaluates if a lacertus release alters the maximal perineural pressure (Pmax) of the median nerve at the level of the lacertus fibrosus during elbow flexion. METHODS: Seven upper limbs from four fresh cadavers were included. Perineural pressure of the median nerve at the level of the lacertus fibrosus was measured continuously during automated elbow flexions by the biceps brachii muscle. RESULTS: The mean Pmax before the lacertus release was significantly different than the mean Pmax after the lacertus release (669.15 mmHg vs 77.01 mmHg, p = 0.0180). The mean Pmax after the lacertus release decreased with an average 81.41%. CONCLUSION: A simple surgical release of the lacertus fibrosus significantly decreases the maximal perineural pressure of the median nerve at the level of the lacertus fibrosus during elbow flexion.

The biomechanical role of the lacertus fibrosus of the biceps brachii Muscle.

PURPOSE: The lacertus fibrosus (LF) is involved in various surgeries. However, the biomechanical contribution of the LF remains unclear. The aim of this study was to determine the role of the lacertus fibrosus on the elbow and forearm kinematics and on the biceps brachii muscle lever arms. METHODS: This biomechanical study was performed on seven fresh-frozen upper limbs of cadavers. Elbow flexion, forearm supination, and biceps brachii muscle lever arms were analyzed in the intact conditions (I) and after superficial (R) and deep part (R2) of the lacertus fibrosus release, respectively. RESULTS: Elbow flexion shows a significant difference (p < 0.0001) between I, R, R2. Abduction/adduction shows a significant difference between I-R (p < 0.0001) and I-R2 (p < 0.0001). Supination does not show a significant difference in mean maximum amplitude, but between 40 and 70%, there are significant differences. There is a significant mean decrease of lever arm in flexion (28%) and supination (50%) after superficial and deep part of the lacertus fibrosus release. CONCLUSION: The results of this study show that the lacertus fibrosus increases the lever arm during flexion and supination. It limits the flexion and abduction of the elbow and supination of the forearm. Lacertus fibrosus maintains the rhythmicity between the elbow flexion and supination of the forearm. LEVEL OF EVIDENCE: Basic science study, biomechanics.

High-resolution ultrasound in the assessment of the distal biceps brachii tendinous complex.

OBJECTIVE: To establish a high-resolution US technique that enables a systematic morphometric examination of the three components that form the distal biceps brachii tendinous complex; the internal bicipital aponeurosis, the distal biceps brachii tendon and the external bicipital aponeurosis (also known as lacertus fibrosus). MATERIALS AND METHODS: Fifty cryopreserved cadaver body donor elbows were dissected to obtain morphometric reference values and to establish reliable landmarks for the US examination. Then, a systematic US technique was designed and validated by a one-to-one US/dissection analysis of 11 cryopreserved cadaver body donor elbows. Finally, the systematic US technique was carried out in 44 healthy volunteers and morphometric parameters were compared to those obtained in the first part of the study. RESULTS: Mean dissection reference values: internal bicipital aponeurosis width 39.61 mm (10.02 SD) and thickness 0.75 mm (0.24 SD), distal biceps brachii tendon width 8.38 mm (1.87 SD) and thickness 2.73 mm (0.69 SD), external bicipital aponeurosis width 11.17 mm (5.84 SD) and thickness 0.85 mm (0.28 SD). One-to-one US/dissection correlation was overall good (intraclass correlation coefficient 0.876, p < 0.0001). When comparing volunteer US/dissection measurements, significant differences were encountered in all measures except for internal bicipital aponeurosis width. However, the overall magnitude of such significant differences was < 0.7 mm. CONCLUSIONS: Using the systematics hereby proposed, high-resolution US is reliable for the morphometric assessment of the distal biceps brachii tendinous complex. The external bicipital aponeurosis is morphometrically the most variable structure.

Ultrasound classification of traumatic distal biceps brachii tendon injuries.

OBJECTIVE: The present work is aimed at analysing ultrasound findings in patients with distal biceps brachii tendon (DBBT) injuries to assess the sensitivity of ultrasound in detecting the different forms of injury, and to compare ultrasound results with magnetic resonance imaging (MRI) and surgical results. MATERIALS AND METHODS: A total of 120 patients with traumatic DBBT injuries examined between 2011 and 2015 were analysed. We compared ultrasound results with MRI results when surgery was not indicated and with MRI and surgical results when surgery was indicated. RESULTS: For major DBBT injuries (complete tears and high-grade partial tears), the concordance study between exploration methods and surgical results found that ultrasound presented a slight statistically significant advantage over MRI (ultrasound: κ = 0.95-very good-95% CI 0.88 to 1.01, MRI: κ = 0.63-good-95% CI 0.42 to 0.84, kappa difference p < 0.01). Minor injuries, in which most tendon fibres remain intact (tendinopathies, elongations and low-grade partial tears), are the most difficult to interpret, as ultrasound and MRI reports disagreed in 12 out of 39 cases and no surgical confirmation could be obtained. CONCLUSIONS: Based on present results and previous MRI classifications, we establish a traumatic DBBT injury ultrasound classification. The sensitivity and ultrasound-surgery correlation results in the diagnosis of major DBBT injuries obtained in the present study support the recommendation that ultrasound can be used as a first-line imaging modality to evaluate DBBT injuries.

Ultrasound visualization of an underestimated structure: the bicipital aponeurosis.

PURPOSE: We established a detailed sonographic approach to the bicipital aponeurosis (BA), because different pathologies of this, sometimes underestimated, structure are associated with vascular, neural and muscular lesions; emphasizing its further implementation in routine clinical examinations. METHODS: The BA of 100 volunteers, in sitting position with the elbow lying on a suitable table, was investigated. Patients were aged between 18 and 28 with no history of distal biceps injury. Examination was performed using an 18-6 MHz linear transducer (LA435; system MyLab25 by Esaote, Genoa, Italy) utilizing the highest frequency, scanned in two planes (longitudinal and transverse view). In each proband, scanning was done with and without isometric contraction of the biceps brachii muscle. RESULTS: The BA was characterized by two clearly distinguishable white lines enveloping a hypoechoic band. In all longitudinal images (plane 1), the lacertus fibrosus was clearly seen arising from the biceps muscle belly, the biceps tendon or the myotendinous junction, respectively. In transverse images (plane 2) the BA spanned the brachial artery and the median nerve in all subjects. In almost all probands (97/100), the BA was best distinguishable during isometric contraction of the biceps muscle. CONCLUSION: With the described sonographic approach, it should be feasible to detect alterations and unusual ruptures of the BA. Therefore, we suggest additional BA scanning during clinical examinations of several pathologies, not only for BA augmentation procedures in distal biceps tendon tears.

Anatomical variations of the biceps brachii insertion: a proposal for a new classification.

BACKGROUND: The biceps brachii (BB) muscle is one of the three muscles located in the anterior compartment of the arm. Its insertion consists of two parts. The first part - main tendon - attached in the radial tuberosity and the second part - lacertus fibrosus (LF) - in the fascia of the forearm flexors. The intention of research was to reveal the morphological diversity of the insertion of this muscle. Thanks to the results of this work, have been created a classification of the distal attachment of BB. The results of that research can be used to further develop surgical procedures in the given region. MATERIALS AND METHODS: Eighty (40 left, and 40 right, 42 female, 38 male) upper limbs fixed in 10% formalin solution were examined. RESULTS: We observed three types of the insertion of the BB. Type I was characterised by a single tendon and occurred most frequently in 78.75% of the examined limbs. The second most common type was type II which was characterised by a double tendon and was observed in 13.75% of all the limbs. The last and least common was type III which was characterised by three tendons and occurred in 7.5% of the examined limbs. Additionally, the type of LF was analysed. In 8 (10%) specimens it was absent, i.e. in 2 specimens with type II insertion and 6 specimens with type III (p = 0.0001). Therefore, it may be deduced that type III BB insertion tendon predisposes to LF deficiency. CONCLUSIONS: The BB tendon is characterised by high morphological variability. The new classification proposes three types of distal attachment: type I - one tendon; type II - two separated band-shaped tendons; type III - three separated band-shaped tendons. The presence of type III BB tendon predisposes to a lack of LF.

Bifurcated distal biceps brachii tendon coexisting with separated bicipital aponeurosis: a complex variational case report.

Variations appearing in biceps brachii muscle are common with accessory head, different origins, variant insertion, and different pattern of nerve innervation. However, variations appearing in both origin and insertion, and with other anomalous morphology at the same time are seldom. Here we report a complex variational case on the right arm of a 91-year-old Japanese female cadaver. The complex variations included (1) the biceps brachii muscle bifurcated at its distal ending; (2) the long head had its own tendon, which divided into two parts, i.e., a lateral part fused into the fascia between the brachioradialis and extensor carpi brevis, and a medial part attached to the radius about one centimeter ahead of the radial tuberosity; (3) the short head had an accessory origin from the shoulder capsule; (4) the bicipital aponeurosis was of two parts with an anterior superior layer formed by the long head and a posterior deep one formed by the short head; (5) the musculocutaneous nerve was especially underdeveloped that only innervated the coracobrachialis; (6) the existence of communicating branch between the musculocutaneous and median nerves, and the median nerve issued muscular branches to the biceps brachii and brachialis muscles, and (7) the brachioradial muscle had two accessory muscular bundles that originated from the fascia of the brachial muscle (proximal one) and from the bicipital aponeurosis (distal one).

Acute Upper Extremity Ischaemia as a Result of Muscular Hypertrophy: The Popeye Syndrome.

Arterial entrapment syndrome (AES) at the elbow level is very rare. In cases of acute upper extremity ischaemia presenting in middle-aged patients with evident muscular hypertrophy, AES should always be included in the differential diagnosis. A thorough clinical examination should always follow, particularly when symptoms appear after reported strenuous upper extremity activity, and emergent surgical decompression is mandatory to avoid thrombotic complications in the affected arm in the future.

Augmentation of Distal Biceps Tendon Ruptures With the Lacertus Fibrosus: A Biomechanical Study in a Tendon-Deficient Model.

BACKGROUND: Chronic distal biceps tendon ruptures may require tendon graft augmentation secondary to tendon attrition or retraction. The lacertus fibrosus is a local, cost-effective graft that can be used to supplement reconstruction. PURPOSE: To compare the biomechanical strength of distal biceps tendon repairs with and without lacertus fibrosus augmentation in a tendon-deficient cadaveric model. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen fresh-frozen matched cadaveric pairs of elbows were randomized into 2 groups: (1) standard distal biceps tendon repair and (2) tendon-deficient (50% step cut) repair with lacertus fibrosus augmentation. All repairs were completed using an oval bone trough and 2 double-loaded No. 2 braided nonabsorbable sutures in a locked Krackow fashion tied over a lateral bone bridge. For the lacertus augmentation group, the lacertus was wrapped circumferentially in a tubular fashion around the tendon to restore the native size and incorporated into the Krackow suture. All specimens underwent cyclic loading and then were loaded to failure. Displacement, stiffness, load to failure, and mode of failure were recorded. RESULTS: The standard repair and lacertus augmentation groups had similar displacements on cyclic loading (1.66 ± 0.62 vs 1.62 ± 0.58 mm, respectively; P = .894). The stiffness was significantly greater for the standard repair group (21.3 ± 2.5 vs 18.5 ± 3.5 N/mm; P = .044). Both groups provided excellent mean peak load to failure strengths, despite the standard repair group having significantly greater strength (462.4 ± 140.5 vs 377.3 ± 101.1 N; P = .022). The primary mode of failure in the standard repair group was fracture at the bone bridge (n = 5/8) compared with suture pullout (n = 4/8) in the lacertus augmentation group. CONCLUSION: Lacertus fibrosus augmentation of a tendon-deficient biceps repair was less stiff and had lower mean load to failure compared with repair of the native tendon in this cadaveric model, but these values remained biomechanically acceptable above critical thresholds. Consequently, lacertus fibrosus augmentation is a viable option for chronic distal biceps tendon ruptures with tendon attrition. CLINICAL RELEVANCE: Chronic distal biceps tendon ruptures may require autograft or allograft reconstruction secondary to tendon scarring, shortening, attrition, and degeneration. The lacertus fibrosus is a cost-effective and low-morbidity local autograft that can be used to augment repairs.

Outcome of Distal Biceps Tendon Repair With and Without Concomitant Bicipital Aponeurosis Repair.

BACKGROUND: The bicipital aponeurosis (BA) can often be torn concomitantly with a distal biceps tendon (DBT) rupture. Its repair, although recommended by some, has not commonly been addressed during the surgical management of DBT ruptures, and to date, surgical repair of the BA with DBT repair has not been evaluated clinically. PURPOSE: To utilize subjective and objective outcome measures to examine the safety and efficacy of 2-incision DBT repair with and without repair of the BA in patients with a DBT rupture. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Demographic and surgical data were reviewed retrospectively. Patients returned to the clinic to complete subjective outcome measures and objective measurements of range of motion, strength, and biceps contour. All patients were evaluated at least 1 year after surgical treatment. RESULTS: Data from 24 male patients with a DBT rupture were used for the analysis; 13 (54%) underwent concomitant DBT and BA repair, and 11 (46%) underwent isolated DBT repair. There were no complications at 1 year in either group. The DBT + BA repair group returned to recreational activities faster (77% within 6 months and 100% within 1 year) than the isolated DBT repair group (36% within 6 months, 91% within 1 year, and 100% after more than 2 years) (P = .05). There was a trend toward better Patient-Rated Elbow Evaluation pain scores in the DBT + BA repair group than in the isolated DBT repair group (1.2 vs 5.3, respectively; P = .18). A trend also emerged toward closer return to subjective preinjury strength (77% vs 44%, respectively; P = .14). No significant difference emerged in patient satisfaction with the biceps contour, subjective scores on functional activities and disability, or objective measurements of strength, contour, and range of motion. CONCLUSION: This pilot study suggests that repair of the BA in conjunction with DBT repair leads to a faster return to recreational activities compared with isolated DBT repair. Also noted was a trend toward subjectively improved pain and greater perceived strength, after DBT + BA repair, although this was not statistically significant. Further investigation with a larger population is required to better elucidate these potential differences.