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.

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 of the arm. It 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

Was observed three types of the insertion of the BB. Type I was characterized 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 characterized by a double tendon and was observed in 13.75% of all the limbs. The last and least common was Type III which was characterized by three tendons and occurred in 7.5% of the examined limbs. Additionally, the type of lacertus fibrosus (LF) was analyzed. In eight (10%) specimens it was absent, i.e. in two specimens with type II insertion and six specimens with type III, p = 0.0001. Therefore, it may be deduced that Type III BB insertion tendon predisposes to LF deficiency.

CONCLUSIONS

The biceps brachii tendon is characterized 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.

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.