Biceps brachii long head overactivity associated with elbow flexion contracture in brachial plexus birth palsy

Kinematic Analysis of Reaching Tasks at Different Execution Speeds in Children with Neonatal Brachial Plexus Palsy

The aim of this study was to compare the kinematics of reaching tasks at different speeds between children with neonatal brachial plexus palsy (NBPP) and unaffected controls. This cross-sectional study included thirteen children with NBPP (10 ± 2 years old, of which six had upper Erb's palsy and seven had extended Erb's palsy) matched for age and sex with thirteen unaffected controls. Kinematic data were acquired using a Motion Monitor unit with a 3D motion tracking electromagnetic system (Liberty, Polhemus). Scapular, upper limb, and head were recorded during forward reaching tasks (hand on overhead ball and hand to head) and a backward reaching task (hand on the back pocket). The study revealed reduced shoulder flexion and extension in children with NBPP during hand on ball and on the back pocket tasks compared to unaffected controls. Limited elbow flexion was also observed in children with NBPP during the hand on ball and hand on the head tasks. During the hand to head task, children with NBPP presented increased head flexion compared to unaffected controls. Scapular kinematics analysis showed increased posterior tilt in children with NBPP during forward reaching (the hand on ball and hand to head tasks). In the backward reaching task (hand on the back pocket), the NBPP group exhibited reduced scapular external rotation compared to unaffected controls. These findings indicate distinct kinematics in the scapula, shoulder, elbow, and head during reaching tasks for children with NBPP compared to controls. Furthermore, different execution speeds did not alter the kinematic differences between the groups.

Tendon Lengthening Surgery for Elbow Flexion Contractures in Brachial Plexus Birth Palsy

PURPOSE

Flexion contracture of the elbow is a common deformity associated with brachial plexus birth palsy and is often managed with preventive night orthoses. For severe cases, however, surgical interventions may become necessary. This study evaluated the effectiveness of surgically releasing elbow flexion contractures exceeding 30° through partial tenotomy of the brachialis and biceps brachii muscles, along with a division of the lacertus fibrosus.

METHODS

We performed 36 anterior elbow releases on patients with injury to the upper trunk (C5-C6) of the brachial plexus and elbow flexion contractures between 30° and 80°. All releases involved lacertus fibrosus section and partial lengthening of the distal portion of the brachialis tendon. In severe cases, biceps brachii tenotomy was also performed. All participants had a minimum follow-up of 12 months and preoperative elbow flexion strength of at least grade 4 on the British Medical Research Council scale, with no deformities in the shape of the ulnohumeral joint or radial head subluxation.

RESULTS

Following a mean follow-up of 41 months, the average extension gain was 31° (range, 10°-50°). All patients maintained their flexion strength. Except for two participants with weaker triceps, the mean elbow extension gain was sustained throughout the follow-up period. There were no major or minor complications or reinterventions in the study.

CONCLUSIONS

Partial tenotomy of the brachialis and biceps brachii muscles, coupled with lacertus fibrosus section, is an effective treatment for elbow contractures exceeding 30° flexion. This method is successful in individuals with a functioning triceps brachii and elbow extension strength of at least grade 3 on the British Medical Research Council scale.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

A Novel Operation Technique for Forearm Deformities in Patients with Brachial Plexus Birth Injury: Retrospective Analysis of 14 Patients

Background: We aimed to evaluate the effectiveness of our novel operation technique that included radial shaft shortening plus supination producing osteotomy and transfer of the biceps brachii tendon to the brachialis tendon in patients with chronic radial head dislocation secondary to brachial plexus birth injury (BPBI). Methods: Fourteen patients with chronic radial head dislocation resulting from BPBI were included in this study, with a minimum 1-year postoperative follow-up period. All patients underwent the same surgical procedure. The range of motion of affected elbow was measured with a standard goniometer. The Mayo Elbow Performance Score (MEPS) was used to measure for evaluation of functional result of these patients. The affected elbow radiograph also obtained in the last visit for evaluation of compatibility of the radiocapitellar joint. Results: Fourteen patients (10 males and 4 females) were included in the study. The average age at the time of surgery was 7.2 (5-8) years and average follow-up was 73.2 ± 19 (36-131) months. Although the forearm active-passive pronation decreased, active-passive supination significantly improved postoperatively (p < 0.001). Ten patients had excellent MEPS results (90 and above), two patients with good results (75 and 80), one patient with fair (65) and one patient with poor result (55). Radiocapitellar reduction was achieved in 78.5% (11/14) of the patients. Conclusions: The novel surgical techniques that included radial shaft shortening plus supination producing osteotomy and transfer of the biceps brachii tendon to the brachialis tendon improved the functional outcomes of patients with chronic radial head dislocation secondary to BPBI. Level of Evidence: Level IV (Therapeutic).

Three-Dimensional Upper Limb Movement Analysis in Children and Adolescents With Brachial Plexus Birth Injury: A Systematic Review

BACKGROUND

To synthesize the current evidence on clinical use of three-dimensional upper limb movement analysis (3D-ULMA) in children and adolescents with brachial plexus birth injury (BPBI).

METHODS

MEDLINE, Embase, and Web of Science were searched for relevant studies up to April 2022. An automatic e-mail alert was installed to ensure no eligible article was missed. Articles evaluating 3D-ULMA in children and adolescents with BPBI were included. Covidence web-based platform was used for blind screening of eligible articles. Twenty-one observational studies with a final sample size of 609, encompassing 493 BPBI cases, met the inclusion criteria. Data were extracted using a custom form to support standardized extraction conforming to the Cochrane Checklist of items. Risk of bias was assessed using the Newcastle-Ottawa Scale, the Strengthening the Reporting of Observational Studies in Epidemiology checklist, and a specifically established quality assessment form for kinematic analysis studies.

RESULTS

Study setups differed, including six different types of kinematic devices. Twelve studies used the (modified) Mallet positions for their 3D-ULMA. Throughout the studies, 3D-ULMA was used for various purposes. The Newcastle-Ottawa Scale scored 16 articles with five stars or more, indicating fair to moderate quality.

CONCLUSIONS

This systematic review summarizes the different 3D-ULMA kinematic devices, test protocols, and their clinical use for BPBI. The use of 3D-ULMA provides valuable, objective, and quantified data to clinicians with regard to movement strategies; it complements existing clinical scales and can be implemented to evaluate effectiveness of therapy interventions. Implications for future research and clinical practice are discussed.

The Relationship Between Elbow Flexion Postures and Overhead Reaching in Birth Brachial Plexus Injuries

PURPOSE

The aim of this study was to investigate the effect of alterations in muscle length of the biceps in various elbow postures during shoulder elevation and muscle activation.

METHODS

Participants aged 5 years and older with a birth brachial plexus injury were asked to perform elevation shoulder (abduction and flexion) in 7 elbow conditions. Surface electromyography was applied to bilateral biceps and triceps.

RESULTS

Peak shoulder elevation was present in the immobilized 20° elbow posture. Muscle activity of the triceps and biceps was impacted by the elbow posture via immobilization.

CONCLUSIONS

Elbow postures in elongated postures, via immobilization, may result in higher shoulder elevation due to increased passive forces when there is an altered muscle state of the biceps in this population. Clinicians should consider the optimal elbow joint posture (<30°) to improve overhead reaching in this population.

Can the Sup-ER Protocol Decrease the Prevalence and Severity of Elbow Flexion Deformity in Brachial Plexus Birth Injuries?

BACKGROUND

Brachial plexus birth injuries (BPBIs) can often result in functional and cosmetic deficits including, according to a recent scoping review, elbow flexion contractures in up to 48%. A treatment algorithm that includes a custom long-arm orthosis to optimize early glenohumeral joint positioning (Sup-ER protocol) has been shown to improve shoulder range of motion. Although the protocol was not intentionally designed to affect the elbow, this study investigates the prevalence and severity of elbow flexion contractures in children treated with that protocol.

METHODS

This prospective cross-sectional cohort study examined 16 children aged 4 and older with BPBI severe enough to be treated with the Sup-ER protocol. Passive and active elbow flexion and extension range of motion (ROM) were assessed in both arms. Elbow flexion contractures were defined as > 5^o from neutral.

RESULTS

Within the cohort of 16 patients (mean age: 7.0 years, range: 4.5-11.6 years), the mean maximal passive elbow extension was -6.2° in the affected arm and + 5.1° (hyperextension) in the unaffected arm. Zero patients had a severe elbow flexion contracture (>30^o) and only 6/16 met the lowest threshold definition of elbow flexion contracture (>5^o), with a mean onset at 22 months of age.

CONCLUSIONS

This study suggests an unintended decreased prevalence and severity of elbow flexion contractures in children with more severe BPBI treated with the Sup-ER protocol, relative to published values.

Long-Term Outcomes of Biceps Rerouting for Flexible Supination Contractures in Children With Brachial Plexus Birth Injuries

PURPOSE

Forearm supination contractures occur in 7% of children with brachial plexus birth injuries (BPBI). Biceps rerouting is proposed when pronation has deteriorated but is passively correctable to at least 0° (neutral). The purpose of this investigation was to evaluate long-term outcomes of biceps rerouting for this indication, including magnitude and maintenance of correction, complications, and subsequent osteotomy.

METHODS

We conducted a retrospective review of all children with BPBI and forearm supination contractures treated with biceps rerouting alone, for the above indications, from 1993 to 2017 with at least 2 years follow-up. Demographic information, BPBI characteristics, surgical details, and ranges of motion were obtained from medical records. Pre- and postoperative active pronation (AP) and supination (AS), elbow flexion contracture, and arc of forearm rotation (Arc) were analyzed using linear mixed-effect models.

RESULTS

Twenty-five children (13 females; 13 left forearms; 15 global BPBI) underwent biceps rerouting at age 7 ± 3 years and were followed for 6 ± 3 years. Before surgery, the mean AP and AS were 6° ± 29° and 62° ± 27°, respectively. At the final follow-up, the mean AP, AS, and Arc were 39° ± 36°, 18° ± 34°, and 57° ± 42°, respectively. AP was significantly improved and AS was significantly decreased by 2 years after surgery and at the final follow-up. Neither Arc nor elbow flexion contracture changed significantly. Two of 25 (8%) children underwent subsequent forearm osteotomy.

CONCLUSIONS

Biceps rerouting in children with BPBI improves the forearm position when pronation is deteriorating by shifting the arc from supination to pronation without decreasing the arc of motion or worsening elbow flexion contractures. There is a low risk of complications and a limited need for subsequent forearm osteotomy. These results are maintained over time. When performed before passive pronation is reduced beyond neutral, this procedure may prevent severe supination contractures and reduce the need for forearm osteotomy.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Brachial plexus birth injury and cerebral palsy lead to a common contracture phenotype characterized by reduced functional muscle length and strength

Introduction

Brachial plexus birth injury (BPBI) and cerebral palsy (CP) both cause disabling contractures for which no curative treatments exist, largely because contracture pathophysiology is incompletely understood. The distinct neurologic nature of BPBI and CP suggest different potential contracture etiologies, although imbalanced muscle strength and insufficient muscle length have been variably implicated. The current study directly compares the muscle phenotype of elbow flexion contractures in human subjects with BPBI and CP to test the hypothesis that both conditions cause contractures characterized by a deficit in muscle length rather than an excess in muscle strength.

Methods

Subjects over 6 years of age with unilateral BPBI or hemiplegic CP, and with elbow flexion contractures greater than 10 degrees on the affected side, underwent bilateral elbow flexion isokinetic strength testing to identify peak torque and impulse, or area under the torque-angle curve. Subjects then underwent needle microendoscopic sarcomere length measurement of bilateral biceps brachii muscles at symmetric joint angles.

Results

In five subjects with unilateral BPBI and five with hemiplegic CP, peak torque and impulse were significantly lower on the affected versus unaffected sides, with no differences between BPBI and CP subjects in the percent reduction of either strength measurement. In both BPBI and CP, the percent reduction of impulse was significantly greater than that of peak torque, consistent with functionally shorter muscles. Similarly, in both conditions, affected muscles had significantly longer sarcomeres than unaffected muscles at symmetric joint angles, indicating fewer sarcomeres in series, with no differences between BPBI and CP subjects in relative sarcomere overstretch.

Discussion

The current study reveals a common phenotype of muscle contracture in BPBI and CP, with contractures in both conditions characterized by a similar deficit in muscle length rather than an excess in muscle strength. These findings support contracture treatments that lengthen rather than weaken affected muscles. Moreover, the discovery of a common contracture phenotype between CP and BPBI challenges the presumed dichotomy between upper and lower motor neuron lesions in contracture pathogenesis, instead revealing the broader concept of “myobrevopathy”, or disorder of short muscle, warranting increased investigation into the poorly understood mechanisms regulating muscle length.

Smart Graphene Nanoplatelet Strain Sensor for Natural Frequency Sensing of Stainless Steel (SS304) and Human Health Monitoring

The main purpose of this article is to monitor the natural frequency of stainless steel (SS304) with and without defect by spray-coated smart graphene nanoplatelet (GNPs)-doped poly (methyl methacrylate) (PMMA) nanocomposite strain sensor and human health by smart Lycra denim textile sensor. Methods such as impact hammer test and NI-daq, finite element method (FEM) simulation by Abaqus 6.12, and fast Fourier transform (FFT) study were applied for frequency monitoring of SS304. For human health monitoring, edema disease inspection, cough, and biceps locomotion were studied by graphene sol–gel textile sensor. We report eight sensors fabricated by scotch tape exfoliation method and their sensitivity was checked in terms of gauge factor (GF). The highest and lowest GF-based sensors were checked for sensitivity in the defect (hole) specimen. These sensors were used to sense the natural frequency of SS304 at three different positions in the cantilever beam. The same quantity of GNPs was used for making Lycra denim textile sensors for human health monitoring. The Lycra denim textile sensor showed a 216% change in resistance in the left calf muscle, which is less than right leg flexibility, indicating good sensitivity. In addition, the textile sensor helped in sensing coughing and biceps monitoring. The ease in fabrication and high sensitivity demonstrate the potential ability of GNPs for futuristic smart material for structural and human health monitoring.

Motion Analytics of Trapezius Muscle Activity in an 18-Year-Old Female with Extended Upper Brachial Plexus Birth Palsy

Background  The trapezius muscle is often utilized as a muscle or nerve donor for repairing shoulder function in those with brachial plexus birth palsy (BPBP). To evaluate the native role of the trapezius in the affected limb, we demonstrate use of the Motion Browser, a novel visual analytics system to assess an adolescent with BPBP.

Method  An 18-year-old female with extended upper trunk (C5–6–7) BPBP underwent bilateral upper extremity three-dimensional motion analysis with Motion Browser. Surface electromyography (EMG) from eight muscles in each limb which was recorded during six upper extremity movements, distinguishing between upper trapezius (UT) and lower trapezius (LT). The Motion Browser calculated active range of motion (AROM), compiled the EMG data into measures of muscle activity, and displayed the results in charts.

Results  All movements, excluding shoulder abduction, had similar AROM in affected and unaffected limbs. In the unaffected limb, LT was more active in proximal movements of shoulder abduction, and shoulder external and internal rotations. In the affected limb, LT was more active in distal movements of forearm pronation and supination; UT was more active in shoulder abduction.

Conclusion  In this female with BPBP, Motion Browser demonstrated that the native LT in the affected limb contributed to distal movements. Her results suggest that sacrificing her trapezius as a muscle or nerve donor may affect her distal functionality. Clinicians should exercise caution when considering nerve transfers in children with BPBP and consider individualized assessment of functionality before pursuing surgery.

Corrective Procedure for Flexion Contracture of the Elbow in Neonatal Palsy Sequelae: Long-term Follow-up

BACKGROUND

Aim of this paper is to validate a procedure for correcting elbow flexion contracture in patients suffering from brachial plexus neonatal palsy sequelae during their teens. Elbow flexion contracture represents an unsolved problem in the natural history of obstetric brachial plexus palsy (OBPP) because of the consistent deformity recurrence. Following a previous paper, in which an original technique was proposed in a small sample of patients, the authors show the possible correction of the deformity in a larger group of patients.

METHODS

The procedure includes a combination of a posterior approach to the elbow with olecranon tip section and an anterior one with capsulotomy and soft tissue release to improve elbow range of motion. A series of 26 patients, who underwent the procedure, were checked out in medium and long term. Collected data were age, type of brachial plexus palsy, length of hospitalization, duration of surgery, preoperative and postoperative elbow range of motion, preoperative and postoperative DASH scores and satisfaction scores. Explaining further details about the procedure, the Authors report their results, including a statistical analysis.

RESULTS

At the final follow-up, the mean increase of elbow extension was about 22°. Functional outcomes were successful as well, with a mean increase of 10 points of DASH score. Over 75% of patients were fully satisfied with their outcome.

CONCLUSIONS

The outcome has confirmed the good efficacy of the procedure in increasing elbow extension but also in improving cosmetic appearance in adolescents suffering from flexed elbow in OBPP sequelae.

Functional Elbow Range of Motion in Children and Adolescents

BACKGROUND

The functional elbow range of motion in children and adolescents has not been previously reported. In adults, a functional motion arc of 30 to 130 degrees of elbow flexion and 50 degrees of pronation to 50 degrees of supination is well established. Contemporary tasks such as cellular phone use and keyboarding require greater elbow flexion and pronation than the functional motion arc. Whether or not this is true in children has yet to be established. We hypothesize that to perform functional and contemporary tasks, children and adolescents use a greater range of elbow motion and forearm rotation as compared with adults.

METHODS

Twenty-eight subjects performed 8 functional tasks and 4 contemporary tasks. Kinematic data were captured using a 3-dimensional motion analysis system as previously described. Mean and SD was collected for elbow flexion, extension, pronation, and supination. Unpaired t tests were performed to compare elbow kinematics of children 6- to 11-year-old (n=14) to that of adolescents 12- to 17-year-old (n=14), with a significance criterion of P-value <0.05.

RESULTS

The mean arc of motion to achieve functional tasks was 28 to 146 degrees of elbow extension/flexion and 54 degrees of supination to 65 degrees of pronation. Contemporary tasks utilized 40 to 148 degrees of elbow extension/flexion and 49 degrees of supination to 65 degrees of pronation. A greater supination/pronation arc (107 degrees) and greater elbow flexion (148 degrees) were used to bring a cellular phone to the ear, whereas greater pronation (65 degrees) was used to type on a keyboard. Statistically significant differences were observed between children and adolescents in each of the 12 tasks, with the exception of using a fork.

CONCLUSIONS

A motion arc of 30 to 130 degrees of elbow flexion and 50 to 50 degrees of pronation/supination is sufficient to achieve most positional and functional tasks in children and adolescents. However, specific contemporary tasks such as the use of a cellular phone and typing on a keyboard utilize more elbow flexion and pronation. Awareness of greater use of flexion and pronation to achieve contemporary tasks may help guide surgeons in the care of patients with posttraumatic elbow and forearm deformities and contractures.

LEVEL OF EVIDENCE

Level II-investigation of a diagnostic test.

The morphologic change of the elbow with flexion contracture in upper obstetric brachial plexus palsy

BACKGROUND

Contracture of the elbow after obstetric brachial plexus palsy (OBPP) is well known; however, details of the 3-dimensional (3D) morphologic changes in the elbow joint in OBPP have not been clarified. This study aimed to clarify the 3D morphologic changes in the elbow joint by focusing on the distal humerus with flexion contracture in upper OBPP. We tested the hypothesis that the shape of the distal humerus with flexion contracture in upper OBPP is hypoplastic in the trochlea, capitellum, and olecranon fossa.

METHODS

We retrospectively studied 20 patients with elbow flexion contracture and residual OBPP. The approximate radius of the distal humerus, the shortest distance between the olecranon and coronoid fossa, and the size of the olecranon fossa were measured and compared between the affected and normal sides using 3D bone models to assess the distal humerus morphology.

RESULTS

The average radius of the distal humerus was smaller on the affected side than on the normal side. Furthermore, the average distance between the olecranon and coronoid fossa was greater and the average size of the olecranon fossa was smaller on the affected side than on the normal side. The size of the distal humerus was significantly smaller and the olecranon fossa was significantly shallower on the affected side.

CONCLUSIONS

Consistent with our original hypothesis, the distal humerus with flexion contracture in upper OBPP was hypoplastic. The shallow olecranon fossa might prevent full extension of the elbow even though soft tissue contracture release is performed. We recommend evaluation of the morphology of the olecranon fossa to determine the treatment plan for elbow flexion contracture with OBPP.

Motion Browser: Visualizing and Understanding Complex Upper Limb Movement Under Obstetrical Brachial Plexus Injuries

The brachial plexus is a complex network of peripheral nerves that enables sensing from and control of the movements of the arms and hand. Nowadays, the coordination between the muscles to generate simple movements is still not well understood, hindering the knowledge of how to best treat patients with this type of peripheral nerve injury. To acquire enough information for medical data analysis, physicians conduct motion analysis assessments with patients to produce a rich dataset of electromyographic signals from multiple muscles recorded with joint movements during real-world tasks. However, tools for the analysis and visualization of the data in a succinct and interpretable manner are currently not available. Without the ability to integrate, compare, and compute multiple data sources in one platform, physicians can only compute simple statistical values to describe patient's behavior vaguely, which limits the possibility to answer clinical questions and generate hypotheses for research. To address this challenge, we have developed MOTION BROWSER, an interactive visual analytics system which provides an efficient framework to extract and compare muscle activity patterns from the patient's limbs and coordinated views to help users analyze muscle signals, motion data, and video information to address different tasks. The system was developed as a result of a collaborative endeavor between computer scientists and orthopedic surgery and rehabilitation physicians. We present case studies showing physicians can utilize the information displayed to understand how individuals coordinate their muscles to initiate appropriate treatment and generate new hypotheses for future research.

Result of modified Outerbridge-Kashiwagi procedure for elbow flexion contractures in brachial plexus birth injury

We report the results of ten consecutive patients who had correction of an elbow flexion contracture of greater than 30° in brachial plexus birth injury using a modified Outerbridge-Kashiwagi procedure. All patients had minimum 23-month follow-up. Pre- and post-operative elbow range of motion and DASH scores were recorded in all patients. The operative technique for the procedure and post-operative course is discussed. Surgery was supplemented by botulinum toxin injection into the biceps brachii muscle in most cases. The average age at surgery was 14 years 10 months. The initial plexus lesion was global in eight patients and upper in two. Pre-operative flexion contractures averaged 51° (range 35 to 60) and post-operative averaged 21° (range 15 to 30). Of these patients, one had no change in active flexion, four had loss of active flexion, and five had gain of active flexion. All ten patients were satisfied with their results and stated that they would recommend the procedure to other patients. Level of evidence: IV.

Prevalence and etiology of elbow flexion contractures in brachial plexus birth injury: A scoping review

PURPOSE

To synthesize the evidence on the prevalence and etiology of elbow flexion contractures secondary to brachial plexus birth injury (BPBI).

METHODS

Using Arksey and O'Malley's scoping review framework, MEDLINE, EMBASE, PsycINFO, and CINAHL databases were searched, followed by a comprehensive grey literature search. Articles and abstracts of studies of all level of evidence on the prevalence, natural history, clinical presentation, etiology, and treatment of elbow flexion contractures in BPBI were included.

RESULTS

Of the 884 records found, 130 full text articles were reviewed, and 57 records were included. The median prevalence of elbow flexion contracture in BPBI was 48%. The magnitude of the contractures was between 5 and 90 degrees. Contractures > 30 degrees were found in 21% to 36% of children. With recent clinical and lab studies, there is stronger evidence that the contractures are largely due to the effects of denervation causing failure in the growth of the affected flexor muscles, while muscle imbalance, splint positioning, and postural preferences play a smaller role.

CONCLUSION

The etiology of elbow flexion contractures is multifaceted. The contribution of growth impairment in the affected muscles offers greater understanding as to why maintaining passive range of motion in these contractures can be difficult.

Correction of elbow flexion contracture by means of olecranon resection and anterior arthrolysis in obstetrical brachial plexus palsy sequelae

The authors have developed a particular surgical technique (olecranon bone resection together with anterior elbow arthrolysis) to increase the elbow's range of motion in adolescents and young adults suffering from elbow flexion contracture in obstetrical palsy sequelae. The surgical procedure was carried out in a preliminary group of 11 patients. The original procedure included a double incision: first of all by means of a posterior approach to resect the tip of the olecranon and then another incision carried out through the anteromedial aspect of the elbow, with a view to performing the anterior capsulotomy. Preoperatively, the average clinical elbow extension was 64.9°, whereas after surgery, the value increased to 43.63°. The average DASH score was 38.27 points before surgery, whereas it decreased to 29.98 points after surgery. A statistical analysis was also carried out to confirm the outcome. The procedure is reliable, is not time-consuming, and does not lead to any major complications.

Biceps Tendon Lengthening Surgery for Failed Serial Casting Patients With Elbow Flexion Contractures Following Brachial Plexus Birth Injury

OBJECTIVE

Assessment of surgical outcomes of biceps tendon lengthening (BTL) surgery in obstetric brachial plexus injury (OBPI) patients with elbow flexion contractures, who had unsuccessful serial casting.

BACKGROUND

Serial casting and splinting have been shown to be effective in correcting elbow flexion contractures in OBPI. However, the possibilities of radial head dislocations and other complications have been reported in serial casting and splinting. Literature indicates surgical intervention when such nonoperative techniques and range-of-motion exercises fail. Here, we demonstrated a significant reduction of the contractures of the affected elbow and improvement in arm length to more normal after BTL in these patients, who had unsuccessful serial casting.

METHODS AND PATIENTS

Ten OBPI patients (6 girls and 4 boys) with an average age of 11.2 years (4-17.7 years) had BTL surgery after unsuccessful serial casting.

RESULTS

Mean elbow flexion contracture was 40° before and 37° (average) after serial casting. Mean elbow flexion contracture was reduced to 8° (0°-20°) post-BTL surgical procedure with an average follow-up of 11 months. This was 75% improvement and statistically significant (P < .001) when compared to 7% insignificant (P = .08) improvement after serial casting.

CONCLUSION

These OBPI patients in our study had 75% significant reduction in elbow flexion contractures and achieved an improved and more normal length of the affected arm after the BTL surgery when compared to only 7% insignificant reduction and no improvement in arm length after serial casting.

Perspectives on glenohumeral joint contractures and shoulder dysfunction in children with perinatal brachial plexus palsy

Shoulder joint deformities continue to be a challenging aspect of treating upper plexus lesions in children with perinatal brachial plexus palsy (PBPP). It is increasingly recognized that PBPP affects the glenohumeral joint specifically, and that abnormal scapulothoracic movements are a compensatory development. The pathophysiology and assessment of glenohumeral joint contractures, the progression of scapular dyskinesia and skeletal dysplasia, and current shoulder imaging techniques are reviewed.

"Popeye muscle" morphology in OBPI elbow flexion contracture

BACKGROUND

The pathophysiology of elbow flexion contracture (EFC) in obstetrical brachial plexus injury (OBPI) is not established. In basic science models, neonatal denervation leads to impaired muscle growth. In clinical studies, diminished growth is correlated with extent of denervation, and improved with surgical repair. In EFC, the biceps are clinically short and round vs the contralateral size, termed the "Popeye muscle". The objective of this study was to determine if the biceps morphology (muscle belly and tendon length) in arms with EFC secondary to OBPI is different vs the contralateral.

METHODS

This is a retrospective matched-cohort study. Patients with unilateral EFC (>20°) secondary to OBPI were identified (median = 6.6 years, range = 4.7-16.8). A blinded radiologist used computed tomography to measure length of the biceps short head muscle belly, and tendon bilaterally using standardised anatomical landmarks.

RESULTS

Twelve patients were analyzed. The biceps muscle belly in the injured arm was shorter in all patients vs contralateral, mean difference = 3.6 cm (80%), p < 0.001. The biceps tendon in the injured arm was longer in all patients vs contralateral, mean difference = 1.13 cm (127%), p < 0.001. The total biceps length in the injured arm was shorter in all patients vs contralateral, mean difference = 2.5 cm (89%), p < 0.001.

CONCLUSIONS

This is the first human study confirming growth discrepancy of an elbow flexor in EFC. Distinct biceps morphology is demonstrated, with a significantly shorter muscle belly and overall length, but longer tendon vs normal. This is termed the "Popeye muscle" for its irregular morphology. Findings are consistent with impaired limb growth in denervation.

Contributions of muscle imbalance and impaired growth to postural and osseous shoulder deformity following brachial plexus birth palsy: a computational simulation analysis

PURPOSE

Two potential mechanisms leading to postural and osseous shoulder deformity after brachial plexus birth palsy are muscle imbalance between functioning internal rotators and paralyzed external rotators and impaired longitudinal growth of paralyzed muscles. Our goal was to evaluate the combined and isolated effects of these 2 mechanisms on transverse plane shoulder forces using a computational model of C5-6 brachial plexus injury.

METHODS

We modeled a C5-6 injury using a computational musculoskeletal upper limb model. Muscles expected to be denervated by C5-6 injury were classified as affected, with the remaining shoulder muscles classified as unaffected. To model muscle imbalance, affected muscles were given no resting tone whereas unaffected muscles were given resting tone at 30% of maximal activation. To model impaired growth, affected muscles were reduced in length by 30% compared with normal whereas unaffected muscles remained normal in length. Four scenarios were simulated: normal, muscle imbalance only, impaired growth only, and both muscle imbalance and impaired growth. Passive shoulder rotation range of motion and glenohumeral joint reaction forces were evaluated to assess postural and osseous deformity.

RESULTS

All impaired scenarios exhibited restricted range of motion and increased and posteriorly directed compressive glenohumeral joint forces. Individually, impaired muscle growth caused worse restriction in range of motion and higher and more posteriorly directed glenohumeral forces than did muscle imbalance. Combined muscle imbalance and impaired growth caused the most restricted joint range of motion and the highest joint reaction force of all scenarios.

CONCLUSIONS

Both muscle imbalance and impaired longitudinal growth contributed to range of motion and force changes consistent with clinically observed deformity, although the most substantial effects resulted from impaired muscle growth.

CLINICAL RELEVANCE

Simulations suggest that treatment strategies emphasizing treatment of impaired longitudinal growth are warranted for reducing deformity after brachial plexus birth palsy.

Late reconstruction of brachial plexus birth palsy

Brachial plexus birth palsy (BPBP) presents to the physician on a clinical spectrum, and may substantially impair the child. Potential interventions to improve function for the child with BPBP include physical therapy, microsurgical nerve reconstruction and nerve transfers, soft-tissue balancing and reconstruction with musculotendinous transfers, and osteotomies. Some interventions, such as nerve reconstruction, are best performed in infancy; others, such as muscle transfers and osteotomies, are performed to treat manifestations of this condition that appear later in childhood. Although controversy continues to exist regarding the natural history and surgical management of these patients, recent literature has improved our understanding of surgical indications, anticipated outcomes, and potential complications. On the basis of current evidence, we present here the recommendations for surgical intervention in the upper extremity of children with BPBP, and encourage early referral to a brachial plexus specialist to establish care.

Elbow Flexion Contractures in Childhood in Obstetric Brachial Plexus Lesions: A Longitudinal Study of 20 Neurosurgically Reconstructed Infants with 8-Year Follow-up

OBJECTIVE

 Little knowledge exists on the development of elbow flexion contractures in children with obstetrical brachial plexus lesion (OBPL). This study aims to evaluate the prognostic significance of several neuromuscular parameters in infants with OBPL regarding the later development of elbow flexion contractures.

METHODS

 Twenty infants with OBPL with insufficient signs of recovery in the first months of life who were neurosurgically reconstructed were included. At a mean age of 4.6 months, the following neuromuscular parameters were assessed: existence of flexion contractures, cross-sectional area (CSA) of upper arm muscles on MRI, Narakas classification, EMG results, and elbow muscle function using the Gilbert score. In childhood at follow-up at mean age of 7.7 years, we measured the amount of flexion contractures and the upper arm peak force (Newton). Statistical analysis is used to assess relations between these parameters.

RESULTS

 Flexion contractures of greater than 10 degrees occurred in 55% of our patient group. The relation between the parameters in infancy and the flexion contractures in childhood is almost nonexistent. Only the Narakas classification was related to the development of flexion contractures in childhood (p = 0.006). Infant muscle CSA is related to childhood peak muscle force.

CONCLUSION

 The role of infancy upper arm muscle hypotrophy/hypertrophy, reinnervation, and early elbow muscle function in the development of childhood elbow contractures remains unclear. In this cohort prediction of childhood flexion, contractures were not possible using infancy neuromuscular parameters. We suggest that contractures might be an adaptive process to optimize residual muscle function.

Significant improvement in nerve conduction, arm length, and upper extremity function after intraoperative electrical stimulation, neurolysis, and biceps tendon lengthening in obstetric brachial plexus patients

Background

Progressive loss of extension and concomitant bony deformity of the elbow are results of persistent biceps contracture in obstetric brachial plexus injury (OBPI) patients, if they do not fully recover. This adversely affects the growth and development and functions of the upper extremity.

Patients and method

We have performed biceps tendon lengthening (BTL) using a Z-plasty technique on OBPI patients aged 4 years to adulthood, who had been diagnosed with biceps tendon fixed flexion contractures. Ulnar, radial, and median nerve decompression was also performed at the same sitting. Somatosensory evoked potential (SSEP) monitoring was performed by stimulating the median and ulnar nerves at the wrist and the radial nerve over the dorsum of the hand and recording the peripheral, cervical, and cortical responses.

Seven children with obstetric brachial plexus palsy with an average age of 11 years (8.7–14.2 years) were included in this report. Mean follow-up time was 7.4 months (4–11 months). All the patients in this report had the elbow flexion contractures greater than 30°.

Results

Mean flexion contracture was 35° (30°–45°) preoperatively, which was improved to 0°–10° postoperatively with an average follow-up of 7 (4–11) months. This surgical procedure corrected the elbow flexion contractures, about an average of 25° and an improved length almost to normal, and improved the upper extremity functions. Neurophysiological data showed significant improvement in conduction of all three nerves tested after neurolysis. Further, median and radial nerve amplitude increase was statistically significant.

Conclusion

Statistically significant improvement in biceps length as well as nerve conduction was observed after the surgery. None of the children in our study lost biceps function, although weakness of the biceps is both a short- and long-term risk associated with biceps lengthening.

Computational sensitivity analysis to identify muscles that can mechanically contribute to shoulder deformity following brachial plexus birth palsy

PURPOSE

Two mechanisms, strength imbalance or impaired longitudinal muscle growth, potentially cause osseous and postural shoulder deformity in children with brachial plexus birth palsy. Our objective was to determine which muscles, via either deformity mechanism, were mechanically capable of producing forces that could promote shoulder deformity.

METHODS

In an upper limb computational musculoskeletal model, we simulated strength imbalance by allowing each muscle crossing the shoulder to produce 30% of its maximum force. To simulate impaired longitudinal muscle growth, the functional length of each muscle crossing the shoulder was reduced by 30%. We performed a sensitivity analysis to identify muscles that, through either simulated deformity mechanism, increased the posteriorly directed, compressive glenohumeral joint force consistent with osseous deformity or reduced the shoulder external rotation or abduction range of motion consistent with postural deformity.

RESULTS

Most of the increase in the posterior glenohumeral joint force by the strength imbalance mechanism was caused by the subscapularis, latissimus dorsi, and infraspinatus. Posterior glenohumeral joint force increased the most owing to impaired growth of the infraspinatus, subscapularis, and long head of biceps. Through the strength imbalance mechanism, the subscapularis, anterior deltoid, and pectoralis major muscles reduced external shoulder rotation by 28°, 17°, and 10°, respectively. Shoulder motion was reduced by 40° to 56° owing to impaired growth of the anterior deltoid, subscapularis, and long head of triceps.

CONCLUSIONS

The infraspinatus, subscapularis, latissimus dorsi, long head of biceps, anterior deltoid, pectoralis major, and long head of triceps were identified in this computational study as being the most capable of producing shoulder forces that may contribute to shoulder deformity following brachial plexus birth palsy.

CLINICAL RELEVANCE

The muscles mechanically capable of producing deforming shoulder forces should be the focus of experimental studies investigating the musculoskeletal consequences of brachial plexus birth palsy and are potentially critical targets for treating shoulder deformity.