Evaluation of Upper Extremity Reachable Workspace in Children With Brachial Plexus Birth Injury.

PURPOSE: Brachial plexus birth injury (BPBI) results in upper extremity (UE) movement limitations. Current assessments of UE function used to inform clinical decision-making only evaluate a limited set of static postures and/or movements and have been criticized for being insensitive to certain meaningful differences in function. Reachable workspace provides a numeric and visual assessment of global UE movement ability by quantifying the regions in space that patients can reach with their hands, and it can be collected using real-time feedback to elicit a best-effort acquisition of function. This study evaluated the ability of a real-time feedback reachable workspace tool to assess UE movement in BPBI. METHODS: Twenty-two children with BPBI participated. Reachable workspace data were collected with three-dimensional motion capture using real-time visual feedback to measure UE reaching ability in all regions surrounding the body. All outer, far-from-body points reached by the hand were recorded and analyzed by region. A two-way, within-subjects analysis of variance was used to assess interlimb differences in percentage workspace reached and median reach distance for each of the six regions. RESULTS: The affected limb had significantly less percentage workspace reached than the unaffected limb for all six regions (mean interlimb differences by region, 5.7%-38.6%). The affected limb had significantly less median reach distance than the unaffected limb for all six regions (mean interlimb differences by region, 3.1%-36.8%). CONCLUSIONS: The workspace approach was capable of detecting UE movement impairments of the BPBI-affected limb. The reported deficits in workspace on the affected limb correspond to common movement impairments in BPBI, such as limitations in shoulder elevation, external rotation, extension, and elbow extension. CLINICAL RELEVANCE: The real-time feedback reachable workspace tool is sufficiently robust for assessing UE movement impairments in children with BPBI.

Impact of tendon transfer on scapulothoracic and glenohumeral motion in children with brachial plexus birth injuries.

BACKGROUND: Tendon transfers are often utilized to improve shoulder external rotation and abduction in children with brachial plexus birth injuries and are designed to improve glenohumeral (GH) joint motion. However, changes in scapulothoracic (ST) and glenohumeral (GH) joint function after tendon transfer are not well defined. The purpose of this study was to quantify changes in GH, ST, and humerothoracic (HT) joint function before and after tendon transfer, and we hypothesized that tendon transfers would reorient the arc of motion into more external rotation and abduction, but not increase GH motion. METHODS: Motion analysis was performed in 15 children (ages 3-16) before and after transfer of teres major and/or latissimus dorsi. Scapulothoracic, GH, and HT joint angles were measured in a neutral, resting position and each of the modified Mallet positions. Joint angular displacements from the neutral position and the total arc of internal-external rotation for each joint were also calculated. Relevant joint angles, joint angular displacements, and internal-external rotation arcs were compared using multivariate analyses of variance with repeated measures and univariate post-hoc analyses. RESULTS: Glenohumeral and HT external rotation were significantly increased in all positions postoperatively. The arc of GH internal-external rotation was unchanged, but oriented in more external rotation after surgery. Only 6 patients gained active external rotation. Glenohumeral and HT internal rotation were significantly decreased after surgery, but ST internal rotation was significantly increased. Two patients had loss of midline function. In the abduction position, GH elevation joint angles were unchanged, but ST and HT elevation increased. DISCUSSION: Only four patients gained active GH external rotation and maintained their internal rotation. Each of those patients underwent isolated tendon transfer without concomitant joint release. Seven patients maintained their preoperative internal rotation, which was attributed to increased ST internal rotation. The other half of patients lost internal rotation and gained external rotation through reorientation of the arc of rotation. Nine patients gained HT elevation, with three attributed to increased ST upward rotation, five attributed to a combination of increased ST upward rotation and increased GH elevation, and one attributed to increased GH abduction contracture. These findings challenge the dogma that teres major/latissimus dorsi tendon transfers augment GH motion and highlight the importance of ST function for outcome determination.

Scapulothoracic and Glenohumeral Contributions to Humerothoracic Kinematics in Single Versus Double Tendon Transfers in Patients With Brachial Plexus Birth Injury.

PURPOSE: Evidence suggests that patients with brachial plexus birth injury are more likely to retain midline function following a teres major tendon transfer without a concomitant latissimus dorsi transfer. Both procedures increase shoulder external rotation and abduction, but whether increased loss of midline frequency following double transfer is due to glenohumeral (GH) joint motion or scapulothoracic (ST) compensation is unknown. We hypothesized that double tendon transfers would exhibit greater GH external rotation than single tendon transfers, thus requiring greater ST rotation to internally rotate the shoulder, while GH and ST contributions to elevation remained equivalent between both groups. METHODS: Twenty-six postsurgical children with C5/C6 brachial plexus birth injuries participated in this study. Thirteen patients with single tendon transfers were matched with 13 with double tendon transfer. Coordinate systems of the thorax, scapula, and humerus were measured utilizing motion capture in 6 arm positions. Joint angles were calculated by the helical (ST) and modified globe method (GH and humerothoracic [HT]). Differences between groups were compared with repeated measures of multivariate analyses of variance for each position. Pending significant multivariate analyses of variance, univariate analyses of variance determined joint differences between transfer groups. RESULTS: Joint rotations from neutral were similar between groups in 5 of 6 tested positions, with double tendon transfers consistently demonstrating 15°-20˚ more internal rotation at the GH and HT joints. Still, only the internal rotation position showed statistically significant differences in GH and HT joint angles. The ST joint angles were similar in this position (45.2˚ and 48.5˚). CONCLUSIONS: The arc of motion for patients with double tendon transfer was more internally rotated than in patients with single tendon transfer at the GH and HT joints for all positions. However, both groups demonstrated little active rotation from neutral. Based on this data, teres major-only tendon transfers may not reduce the risk of loss of midline function. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.

Comparison of Shoulder Motion Measurements by Visual Estimate, Goniometer and Motion Capture.

BACKGROUND: Brachial plexus birth injuries (BPBI) can result in lasting impairments of external rotation and cross-body adduction (CBA) that disrupt functional activities such as dressing, grooming, or throwing a ball. The purpose of this study was to compare the quantification of shoulder humerothoracic (HT) external rotation (ER), and glenohumeral (GH) CBA by 3 methods - physician visual estimate, goniometer measurement by an occupational therapist, and motion capture. METHODS: Twenty-six patients with BPBI (average age of 9.9±3.2 y) participated in this study. Mallet scores and visual estimates of passive HT ER and GH CBA were recorded by a physician. The passive measures were repeated by an occupational therapist using a goniometer while motion capture measures were simultaneously collected. Active HT ER was also measured by motion capture. The passive measures were compared with analyses of variance with repeated measures, intraclass correlations, and Bland-Altman plots. External rotation Mallet scores determined by motion capture and by the physician were compared. RESULTS: The measures of GH CBA were not statistically different and demonstrated good agreement, but substantial variation. For HT ER, all measures were significantly different and demonstrated poor agreement and substantial variation. When the joint angles measured by motion capture were used to determine the Mallet score, 79% of external rotation Mallet scores assigned by the physician were incorrectly categorized, with the physician always scoring the participant higher than predicted motion capture Mallet score. CONCLUSIONS: Both GH CBA and HT ER measures demonstrated substantial variability between measurement types, but only HT ER joint angles were significantly different. In addition, more than three-quarters of external rotation Mallet scores were misclassified by the physician. Motion capture measurements offer the benefit of less susceptibility to patients' compensatory and/or out-of-plane movements and should be considered for clinical assessment of shoulder range of motion in children with BPBI. If motion capture is unavailable, the use of a goniometer provides more accurate clinical measures of shoulder motion than visual estimates and care should be taken to minimize and account for compensatory movement strategies. LEVEL OF EVIDENCE: Level IV Case series.

Assessment of the relationship between Brachial Plexus Profile activity short form scores and modified Mallet scores.

INTRODUCTION: This study aims to assess the relationship between the modified Mallet classification and the Brachial Plexus Profile activity short form (BP-PRO activity SF). The therapist or surgeon classifies upper extremity movement for the modified Mallet classification, while the BP-PRO assesses parents' perceptions of difficulty performing activities. PURPOSE: To provide a deeper understanding of the relationship of functional and perceived outcome measurements. STUDY DESIGN: Prospective, correlational design. METHODS: Eighty children with brachial plexus birth injuries were evaluated using the modified Mallet classification, while parents simultaneously answered the BP-PRO activity SF questions. All patients had undergone one of three surgical interventions to improve shoulder function. The relationship between the two measures, patient injury levels, and surgical histories were assessed. RESULTS: The average modified Mallet scores and BP-PRO activity SF scores weakly correlated (r = 0.312, P = .005) and both measures differentiated between C5-6 and C5-7 injury levels (P = .03 and P = .02, respectively). Conversely, the modified Mallet scores could differentiate between the three surgical groups (F = 8.2, P < .001), while the BP-PRO activity SF could not (P = .54). CONCLUSION: The results suggest that these tools measure different aspects of patient outcomes. The Mallet classification may be more focused on shoulder motion than the BP-PRO activity SF. Additional questions that specifically require shoulder function could be incorporated into the BP-PRO activity SF to improve understanding of patient/parent perceptions of shoulder function for children with brachial plexus injuries. Clinicians should be aware of the strengths, weaknesses, and limitations of each outcome assessment tool for appropriate use and interpretation of results.

Effect of Glenohumeral Reduction Type Combined With Tendon Transfer for Brachial Plexus Injury on Objective, Functional, and Patient-Reported Outcomes.

PURPOSE: Glenohumeral (GH) joint reductions are frequently performed during tendon transfer surgery for brachial plexus birth injuries (BPBI); however, the effect of reduction method (none required, closed, surgical) has not been assessed. This study compared objective, functional, and patient-reported outcomes between children who underwent a tendon transfer and (1) did not require GH reduction, (2) required concomitant closed GH reduction, or (3) required concomitant surgical GH reduction. METHODS: Fifty-four children with BPBI who previously underwent teres major and/or latissimus dorsi transfer with or without concomitant GH reduction participated. Joint reduction method was classified as none required (n = 21), closed (n = 9), or surgical (n = 24). Motion capture was collected in a neutral position, abduction, external rotation, and internal rotation. Glenohumeral joint angles and displacements were calculated. Joint angular displacements represented the differences between the joint angles in each terminal position and the joint angles of the arm at rest in the neutral position. A hand surgeon determined modified Mallet scores. Participants' parents completed the Brachial Plexus Profile Activity Short Form (BP-PRO-SF) to assess physical activity performance. RESULTS: The no-reduction group had significantly less GH elevation than the surgical-reduction group for all positions and significantly less GH elevation than the closed-reduction group for the neutral, external rotation, and internal rotation positions. There were no differences in GH rotation angles. Glenohumeral joint displacements from neutral and modified Mallet scores were similar. The no-reduction group demonstrated significantly greater BP-PRO-SF scores than the surgical-reduction group. CONCLUSIONS: Patients who underwent a closed or surgical GH joint reduction consistently displayed more GH elevation. Clinically, this corresponds to an abduction contracture. Whereas increased abduction contracture provided a benefit of greater overhead motion, modified Mallet scores were similar between groups. The surgical-reduction group demonstrated lower BP-PRO-SF outcomes. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Scapular Stabilization Limits Glenohumeral Stretching in Children With Brachial Plexus Injuries.

PURPOSE: To quantify the effects of scapular stabilization on scapulothoracic and glenohumeral (GH) stretching. METHODS: Motion capture data during external rotation and abduction with and without scapular stabilization were collected and analyzed for 26 children with brachial plexus birth palsy. These positions were performed by an experienced occupational therapist and by the child's caretaker. Scapulothoracic and GH joint angular displacements were compared between stretches with no stabilization, stabilization performed by the therapist, and stabilization performed by the caretaker. The relationship between the age and ability of the therapist and caretaker to perform the stretches with scapular stabilization was also assessed. RESULTS: During external rotation there were no significant differences in either the scapulothoracic or GH joint during stabilization by either the therapist or the caretaker. During abduction, both scapulothoracic and GH joint angular displacements were statistically different. Scapulothoracic upward rotation angular displacement significantly decreased with scapular stabilization by the therapist and caretaker. Glenohumeral elevation angular displacement significantly decreased with scapular stabilization performed by the therapist and caretaker. There were only weak correlations between age and the differences in scapulothoracic and GH joint angular displacement performed by both the therapist and the caretaker. CONCLUSIONS: The findings of this study indicate that scapular stabilization may be detrimental to passive stretching of the GH joint in children, as demonstrated by a reduced stretch. Based on the findings of this study, we have changed our practice to recommend passive stretches without scapular stabilization for children aged 5 years and older with brachial plexus birth palsy. In infants and children aged less than 5 years, we now recommend stretching with and without scapular stabilization until the effect of scapular stabilization is objectively assessed in these age groups. LEVEL OF EVIDENCE/TYPE OF STUDY: Therapeutic IV.

Motion Necessary to Achieve Mallet Internal Rotation Positions in Children With Brachial Plexus Birth Palsy.

BACKGROUND: Upper extremity function in children with brachial plexus birth palsy (BPBP) is assessed with clinical tests such as the Mallet classification, which uses a hand to spine position to assess shoulder internal rotation, or the modified Mallet classification, which adds an additional internal rotation task (hand to belly). Children with BPBP frequently have difficulty performing the hand to spine task. This study compared scapulothoracic and glenohumeral (GH) parameters associated with successful completion of the hand to spine and hand to belly modified Mallet positions. METHODS: Motion capture measurement of 32 children with BPBP was performed in hand on spine, internal rotation (hand to belly), hand to mouth, and maximal humerothoracic extension positions. Modified Mallet scores were determined by a hand surgeon. RESULTS: Children with better hand to spine performance demonstrated significantly greater GH extension and a nonsignificant trend toward increased GH internal rotation compared with children with scores <3. Children with better internal rotation position performance demonstrated significantly greater GH internal rotation and no significant difference in GH extension. Hand on spine and internal rotation Mallet scores moderately correlated (Pearson r=0.469); however, 54% of children who could place their palms flat on their bellies could not reach behind their backs. CONCLUSIONS: Successfully reaching behind one's back requires both internal rotation and extension, representing a multiplanar motion. The hand to belly performance is less affected by extension and should be considered for internal rotation assessment, particularly for children undergoing surgical intervention that may affect internal rotation. LEVEL OF EVIDENCE: Level II.

Analysis of Shoulder Complex Function After Posterior Spinal Fusion in Adolescents With Idiopathic Scoliosis.

BACKGROUND: Nonsurgically treated patients with AIS demonstrate altered scapular kinematics and decreased patient-reported shoulder function compared with typically developing adolescents. It is unknown whether surgical correction of the spine deformity has beneficial or detrimental effects on scapulothoracic joint function, as previous assessments of shoulder function following surgery have only focused on humerothoracic motion. The objective of this study was to perform a comprehensive analysis of scapular kinematics before and after PSF and compare postoperative scapular kinematics in AIS to those of a typically developing cohort. METHODS: Typically developing adolescents (n=33) and patients with AIS (n=20) with a planned PSF surgery were recruited. Motion capture was used to analyze scapular kinematics at rest and in full abduction. AIS subjects were evaluated before surgery and at a 6-month follow-up. Individual changes following surgery were assessed, and postoperative scapular kinematics were compared with the typically developing subjects. RESULTS: Patients with AIS patients in this study demonstrated significant losses of scapulothoracic range of motion for the convex side shoulder and gains of scapulothoracic range of motion for the concave side shoulder following PSF. When compared with typically developing adolescents, the resting scapular position of the postoperative AIS group seemed normalized, but the AIS group still exhibited altered scapular motion, particularly along the upward rotation and tilt axes. CONCLUSIONS: Patients with AIS demonstrated significant changes at the scapulothoracic joint following PSF. Compared with typically developing adolescents, scapular resting position normalized, but the AIS group still demonstrated altered scapular kinematics, including patterns associated with shoulder pathology. The results of this study will inform the course of short-term postoperative rehabilitation by addressing the upper extremity implications of PSF for individuals with AIS. LEVEL OF EVIDENCE: Level III.

Shoulder Complex Mechanics in Adolescent Idiopathic Scoliosis and Their Relation to Patient-perceived Function.

BACKGROUND: Proper contribution of the scapulothoracic joint is necessary for adequate shoulder complex function. Associations between trunk shape and abnormal scapular kinematics and subsequent shoulder dysfunction have been established; however, the extent of shoulder dysfunction in adolescent idiopathic scoliosis (AIS) is still poorly understood. The purpose of this study was to perform a comprehensive analysis of scapular kinematics during multiplanar arm motion in patients with AIS and compare kinematics and patient-reported function with that of a typically developing cohort. METHODS: Typically developing adolescents (n=33) and patients with AIS (n=26) with no history of spine or shoulder surgery were recruited for this study. A 3-dimensional optoelectronic motion capture system was used to analyze scapular kinematics in 4 positions: rest, full abduction, forward reach, and hand to spine. Subjects in each group also completed the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire as a measure of patient-reported function. RESULTS: The convex shoulders of the patients with AIS exhibited deficits in scapular upward rotation and posterior tilt in all positions and reduced protraction range of motion during reaching. The AIS group also reported worse patient-perceived shoulder function than the typically developing group; however, this dysfunction was not related to specific scapular kinematic patterns. CONCLUSIONS: Patients with AIS show alterations in scapular kinematics that are associated with shoulder pathology. Despite displaying an unaffected ability to place the hand in space, the underlying joint mechanics place these adolescents at risk for future pathology. Accordingly, consideration of scapulothoracic and glenohumeral joint function is warranted in the treatment of AIS. LEVEL OF EVIDENCE: Level III-cross-sectional comparison.

Efficacy of 3 therapeutic taping configurations for children with brachial plexus birth palsy.

STUDY DESIGN: Cross-sectional clinical measurement study. INTRODUCTION: Scapular winging is a frequent complaint among children with brachial plexus birth palsy (BPBP). Therapeutic taping for scapular stabilization has been reported to decrease scapular winging. PURPOSE OF THE STUDY: This study aimed to determine which therapeutic taping construct was most effective for children with BPBP. METHODS: Twenty-eight children with BPBP participated in motion capture assessment with 4 taping conditions: (1) no tape, (2) facilitation of rhomboid major and rhomboid minor, (3) facilitation of middle and lower trapezius, and (4) facilitation of rhomboid major, rhomboid minor, and middle and lower trapezius (combination of both 2 and 3, referred to as combined taping). The participants held their arms in 4 positions: (1) neutral with arms by their sides, (2) hand to mouth, (3) hand to belly, and (4) maximum crossbody adduction (CBA). The scapulothoracic, glenohumeral and humerothoracic (HT) joint angles and joint angular displacements were compared using multivariate analyses of variance with Bonferroni corrections. RESULTS: Scapular winging was significantly decreased in both the trapezius and combined taping conditions in all positions compared with no tape. Rhomboids taping had no effect. Combined taping reduced HT CBA in the CBA position. CONCLUSIONS: Rhomboid taping cannot be recommended for treatment of children with BPBP. Both trapezius and combined taping approaches reduced scapular winging, but HT CBA was limited with combined taping. Therefore, therapeutic taping of middle and lower trapezius was the most effective configuration for scapular stabilization in children with BPBP. Resting posture improved, but performance of the positions was not significantly improved. LEVEL OF EVIDENCE: Level II.

A Comprehensive Method to Measure 3-Dimensional Bra Motion During Physical Activity.

Breast and bra motion research aims to understand how the breasts/bra move to aid development of apparel that minimizes motion. Most previously published research has tracked nipple motion to represent bra motion. However, this method does not provide information regarding regional tissue motion. A more comprehensive approach might facilitate understanding how the entire soft-tissue mass moves during physical activities. This study developed and tested an objective method to comprehensively measure 3-dimensional bra motion, including regional displacement and velocity, displacement phasing, and surface stretch. To test the method, 6 females were fitted with a minimally supportive, seamless bra (small bra n = 3; large bra n = 3). Data were collected as participants ran on a treadmill. Results indicated marker displacement, velocity, link stretch, and link stretch velocities reached as high as 52.6 (6.8) mm, 504.8 (88.7) mm/s, 29.5% (7.1%) of minimum length, and 3.8 (1.0) mm/s/mm, respectively, with the large bra having greater motions compared with the small. Most bra motion occurred above/below the nipple region and at the bra's strap-body interface, independent of bra size. Importantly, maximum marker displacement and velocity did not occur at the nipple. Measurements obtained from this new method may be important for designing innovative clothing that minimizes bra motion during physical activity.

Errors Associated With Utilizing Prescribed Scapular Kinematics to Estimate Unconstrained, Natural Upper Extremity Motion in Musculoskeletal Modeling.

Musculoskeletal modeling is capable of estimating physiological parameters that cannot be directly measured, however, the validity of the results must be assessed. Several models utilize a scapular rhythm to prescribe kinematics, yet it is unknown how well they replicate natural scapular motion. This study evaluated kinematic errors associated with a model that employs a scapular rhythm using 2 shoulder movements: abduction and forward reach. Two versions of the model were tested: the original MoBL ARMS model that utilizes a scapular rhythm, and a modified MoBL ARMS model that permits unconstrained scapular motion. Model estimates were compared against scapulothoracic kinematics directly measured from motion capture. Three-dimensional scapulothoracic resultant angle errors associated with the rhythm model were greater than 10° for abduction (mean: 16.4°, max: 22.4°) and forward reach (mean: 11.1°, max: 16.5°). Errors generally increased with humerothoracic elevation with all subjects reporting greater than 10° differences at elevations greater than 45°. Errors associated with the unconstrained model were less than 10°. Consequently, use of the original MoBL ARMS model is cautioned for applications requiring precise scapulothoracic kinematics. These findings can help determine which research questions are suitable for investigation with these models and assist in contextualizing model results.

Therapeutic Taping for Scapular Stabilization in Children With Brachial Plexus Birth Palsy.

OBJECTIVE: In this study, we aimed to assess whether therapeutic taping for scapular stabilization affected scapulothoracic, glenohumeral, and humerothoracic joint function in children with brachial plexus birth palsy and scapular winging. METHOD: Motion capture data were collected with and without therapeutic taping to assist the middle and lower trapezius in seven positions for 26 children. Data were compared with one-way multivariate analyses of variance. RESULTS: With therapeutic taping, scapular winging decreased considerably in all positions except abduction. Additionally, there were increased glenohumeral cross-body adduction and internal rotation angles in four positions. The only change in humerothoracic function was an increase of 3° of external rotation in the external rotation position. CONCLUSION: Therapeutic taping for scapular stabilization resulted in a small but statistically significant decrease in scapular winging. Overall performance of positions was largely unchanged. The increased glenohumeral joint angles with therapeutic taping may be beneficial for joint development; however, the long-term impact remains unknown.

Increasing plantarflexion angle during landing reduces vertical ground reaction forces, loading rates and the hip's contribution to support moment within participants.

The ankle joint's role in shock absorption during landing has been researched in many studies, which have found that landing with higher amounts of plantarflexion (PF) results in lower peak vertical ground reaction forces and loading rates. However, there has not yet been a study that compares drop landings within participants along a quantitative continuum of PF angles. Using a custom-written real-time feedback program, participants adjusted their ankles to an instructed PF angle and dropped onto two force platforms. For increasing PF, peak ground reaction force and peak loading rate during weight acceptance decreased significantly. The hip's contribution to peak support moment decreased as PF at initial contact increased up to 30°. The ankle and knee contributions increased over this same continuum of PF angles. There appears to be no optimal PF angle based on peak ground reaction force and loading rate measurements, but there may be an optimum where joint contributions to peak support moment converge and the hip moment's contribution is minimised.

Limited glenohumeral cross-body adduction in children with brachial plexus birth palsy: a contributor to scapular winging.

BACKGROUND: Approximately 1 of every 1000 live births results in life-long impairments because of a brachial plexus injury. The long-term sequelae of persistent injuries include glenohumeral joint dysplasia and glenohumeral internal rotation and adduction contractures. Scapular winging is also common, and patients and their families often express concern regarding this observed scapular winging. It is difficult for clinicians to adequately address these concerns without a satisfying explanation for why scapular winging occurs in children with brachial plexus birth palsy. This study examined our proposed theory that a glenohumeral cross-body abduction contracture leads to the appearance of scapular winging in children with residual brachial plexus birth palsy. METHODS: Sixteen children with brachial plexus injuries were enrolled in this study. Three-dimensional locations of markers placed on the thorax, scapula, and humerus were recorded in the hand to mouth Mallet position. The unaffected limbs served as a control. Scapulothoracic and glenohumeral cross-body adduction angles were compared between the affected and unaffected limbs. RESULTS: The affected limbs demonstrated significantly greater scapulothoracic and significantly smaller glenohumeral cross-body adduction angles than the unaffected limbs. The affected limbs also exhibited a significantly lower glenohumeral cross-body adduction to scapulothoracic cross-body adduction ratio. CONCLUSIONS: The results of this study support the theory that brachial plexus injuries can lead to a glenohumeral cross-body abduction contracture. Affected children demonstrated increased scapulothoracic cross-body adduction that is likely a compensatory mechanism because of decreased glenohumeral cross-body adduction. These findings are unique and better define the etiology of scapular winging in children with brachial plexus injuries. This information can be relayed to patients and their families when explaining the appearance of scapular winging. LEVEL OF EVIDENCE: Level II.

Scapulothoracic and glenohumeral contributions to motion in children with brachial plexus birth palsy.

BACKGROUND: Brachial plexus birth palsy occurs in 0.4 to 4.6 of every 1000 live births, with residual shoulder dysfunction in approximately one third of cases. Clinical measures, such as the Mallet classification, provide no insight into the scapulothoracic and glenohumeral contributions to tested global shoulder movements. This study describes the scapulothoracic and glenohumeral components of shoulder motion during the modified Mallet test. METHODS: Twelve children with Erb's palsy (C5-6) and 8 children with extended Erb's palsy (C5-7) were recruited. The unaffected limbs of 6 subjects were also tested. Locations of markers placed on the thorax, humerus, and scapula were recorded in a neutral position and each of the modified Mallet positions. Scapulothoracic, glenohumeral, and humerothoracic helical displacements and acromion process linear displacements were compared between groups. RESULTS: The brachial plexus birth palsy groups exhibited significantly smaller glenohumeral displacements in all modified Mallet positions and significantly larger scapulothoracic displacements in the global external rotation and hand to mouth positions. Discriminant function analysis using only humerothoracic variables correctly classified 76.9% of subjects. Discriminant function analysis incorporating scapulothoracic, glenohumeral, and acromion process displacement variables produced accuracy of 92.6%. CONCLUSIONS: Children with brachial plexus birth palsy demonstrated decreased glenohumeral contributions to achieve every modified Mallet position and increased scapulothoracic contribution in two positions compared with the unaffected group. Different scapulothoracic and glenohumeral strategies were identified between groups. Finally, scapulothoracic and glenohumeral components of shoulder motion are more specific than humerothoracic measures to diagnostic classification.

Evaluating the acromion marker cluster as a method for measuring scapular orientation in children with brachial plexus birth palsy.

Several studies have described using an acromion marker cluster for measuring scapular orientation in healthy adults performing planar motions. It is unknown whether the acromion marker cluster method will provide the same level of accuracy in children with brachial plexus birth palsy. This study compared this method to palpation for calculating scapular orientation in children with brachial plexus birth palsy performing clinically relevant movements. Scapular orientation in ten patients was determined by palpation and an acromion marker cluster in neutral and six Modified Mallet positions. RMSEs and mean relative errors were calculated. Resultant RMSEs ranged from 5.2 degrees to 21.4 degrees. The averages of the mean relative errors across all positions for each axis were 177.4% for upward/downward rotation, 865.0% for internal/external rotation, and 166.2% for anterior/posterior tilt. The acromion marker cluster method did not accurately measure scapular rotation relative to the total movement on an individual or group basis in the population. With most relative errors over 100%, the acromion marker cluster method often produced errors larger than the actual measured motion. The accuracy of the acromion marker cluster method limits its use as a clinical tool for measuring scapular kinematics on children with brachial plexus birth palsy.

Reachable workspace with real-time motion capture feedback to quantify upper extremity function: A study on children with brachial plexus birth injury.

Clinical upper extremity (UE) functional assessments and motion capture measures are limited to a set of postures and/or motions that may provide an incomplete evaluation of UE functionality. Reachable workspace analysis offers a more global assessment of UE function, but is reliant on patient compliance with instructions and may result in underestimates of a patient's true UE function. This study evaluated a clinical tool that incorporates real-time visual feedback with motion capture to provide an innovative means of engaging patients to ensure a 'best effort' quantification of their available UE workspace. Reachable workspace for 10 children with brachial plexus birth injury was collected with and without real-time feedback on the affected and unaffected limbs. Real-time feedback consisted of subjects reaching for virtual targets surrounding their physical space using a virtual cursor controlled by the real-time location of their hand. Real-time feedback resulted in significantly greater workspace in multiple regions on both the affected (3/6 octants; mean differences 10.8%-20.0%) and unaffected (6/6 octants; mean differences 24.3%-40.0%) limbs. Use of real-time feedback also yielded significant interlimb differences in workspace across more regions (4/6 octants; mean differences 29.0%-39.9% vs. 1/6 octants; mean difference 17%). Finally, real-time feedback resulted in significant interlimb differences in median reach distance across more regions (4/6 octants; mean differences 7.5%-44.8% vs. 1/6 octants; mean difference 11.2%). A reachable workspace tool with real-time feedback results in more workspace and UE function recorded and offers a highly visual and intuitive depiction of a patient's UE abilities.

Assessment of approaches to estimate scapular orientation in children with brachial plexus birth injury.

BACKGROUND: Challenges in measuring dynamic scapular orientation limit assessment of scapulothoracic and glenohumeral contributions to shoulder function in children with brachial plexus birth injury (BPBI). Double calibration acromion marker cluster (D-AMC) and linear model approaches have been validated to estimate scapular motion in healthy adults, but neither has been evaluated in BPBI. RESEARCH QUESTION: Are the linear model and D-AMC approaches able to accurately estimate scapular orientation in children with BPBI at functional arm postures? METHODS: Seventeen children with BPBI positioned their affected limbs in 11 static positions while their segment orientations were measured with motion capture. Linear model and D-AMC estimates of scapular orientation were compared against palpation at six of the static positions with functional relevance to BPBI using a three-way repeat measures ANOVA and a comparison of root mean square errors (RMSE) against literature AMC values for healthy adults. RESULTS: The D-AMC was similar to palpation across all positions and scapular axes while the linear model differed from palpation in a few instances. RMSEs of the D-AMC (3.7-14.8°) and particularly the linear model (4.6-24.8°) were generally at or beyond the upper range of past AMC analyses on healthy adults (1.6-14.2°), especially for more complex, multiplanar arm postures. Despite the D-AMC outperforming the linear model, this approach still produced clinically meaningful (>10°) errors for roughly (12.7-22.5%) of subjects. SIGNIFICANCE: Current methods for estimating dynamic scapular orientation remain less than ideal for BPBI. Use of the D-AMC may be appropriate to gain broad insights into general dynamic scapulothoracic and glenohumeral function; however, given their potential for producing clinically meaningful errors, the D-AMC and linear model are not recommended for diagnostic purposes or outcomes assessment on an individual patient basis unless their patient-specific accuracy has been evaluated and confirmed prior to use.