Active Elbow Research Articles

Modified Unipolar Latissimus Transfer to Restore Elbow Flexion in Musculocutaneous Nerve Palsy

Modified Unipolar Latissimus Transfer to Restore Elbow Flexion in Musculocutaneous Nerve Palsy

Outcomes of nonoperative management of displaced olecranon fractures in medically unwell patients.

BackgroundSurgical treatment of displaced olecranon fractures in the elderly has a high rate of complications, including wound breakdown and fixation failure. The purpose of this study was to assess the clinical, radiographic, and functional outcomes of nonsurgical management of displaced olecranon fractures in low-demand elderly and medically unwell patients.MethodsA retrospective review of 28 patients with displaced closed olecranon fractures was performed with an average follow-up of 11 months. The mean age at the time of injury was 79 ± 10 years. The average Charlson Comorbidity Index was 6.4 ± 2.6. Treatment modalities were at the discretion of the treating surgeon. A sling alone was used in 3 cases, an extension circumferential cast in 9, or a plaster or thermoplastic splint in 16. The mean period of immobilization was 5 ± 1 weeks. Outcomes included range of motion, ability to perform active overhead extension, as well as radiographic and functional outcomes.ResultsAt final follow-up, the mean elbow range of motion for the cohort was from 28° ± 21° extension to 127° ± 15° flexion. Active overhead elbow extension against gravity was noted or documented in 24 (86%) patients. Two patients (7%) were unable to perform active extension. No pain was noted in 18 elbows, severe pain was present in 1 elbow, and the remainder reported mild occasional pain. All olecranon fractures in this cohort were displaced on the initial lateral radiograph. The mean displacement was 11 ± 7 mm. Nonunion at final radiographic outcome was observed in 23 (82%) elbows. Two (7%) patients developed skin complications related to posteriorly placed splints; one of which was severe.DiscussionThis study adds to the growing literature that supports nonoperative management of displaced olecranon fractures in elderly and medically unwell patients with low upper extremity demand. Patients can be counseled that they have a good chance of obtaining overhead extension, with minimal pain. Posteriorly based splints should not be used to minimize skin complications.

Compensatory and adaptive mechanisms in children with congenital multiple arthrogryposis in the absence of active flexion in the elbow joint

To study the compensatory strategies in children with arthrogryposis with absent of active flexion in the elbow joint and estimate their dynamic after surgical treatment. We performed a clinical examination of 236 patients with arthrogryposis with deformities of the upper extremities due to arthrogryposis at the age of 10 months to 16 years. The examination was carried out before the operation, as well as at various times (from 1 month to 8 years) after. In 87 cases (67 patients), restoration of active elbow flexion was performed by transposition of latissimus dorsii or pectoralis major to the biceps position. The activity of the muscles involved that most commonly used in compensatory strategies (synergy of m. biceps brachii and m. deltoideus or m.biceps brachii and m. quadriceps femoris) in 10 patients (from 3 to 10 y.o.), was evaluated before and after (from 2 months to 2 years) surgery by surface electromyography. It was found that children's compensatory strategies are formed at the age of 6 months to 1 y.o.6 months after surgery, the using of compensatory strategies becomes more rare, and 12-18 months after surgery, when the strength of the forearm muscles was 4 points, they were not used at all. Compensatory strategies in children with the absence of active and preservation of passive flexion in the elbow joint are diverse. They depend on the amplitude of passive and active movements in the shoulder, the function of the hand and deformities of the lower extremities. These strategies in children with arthrogryposis are unstable and completely disappear when active movements in the elbow joint are restored in the functional range.

Functional Evaluation of Levator Scapulae Tendon to Supraspinatus in Adult Brachial Plexus Injuries.

Introduction Brachial plexus injuries are severe life-altering injuries. The surgical method to restore shoulder abduction in adult upper brachial plexus injuries involves the usage of nerve grafts and nerve transfers targeting the suprascapular and/or the axillary nerve. When the primary nerve surgery has been unsuccessful or recovery has been incomplete or with a late presentation, muscle transfer procedures are needed to provide or improve shoulder abduction. Levator scapulae to supraspinatus is a transfer to improve shoulder abduction in posttraumatic brachial plexus injuries. Material and Methods The study included 13 patients with the age ranging from 17 to 47 years with a mean age of 30 years. All these patients had preop shoulder abduction of Medical Research Council (MRC) grade ≤3. All had a minimum of MRC grade 4 of active elbow flexion. Eleven patients had primary surgery. Only patients with a minimum of 1 year postoperative follow-up were included. All 13 patients underwent levator scapulae transfer only. Results All patients had a stable shoulder postoperatively. The average increase in active shoulder abduction was from 6.15°(median: 0°) preoperatively to 61.92°(median: 60°), with an average gain in shoulder abduction of 49.61°(median: 50°). Conclusions Transfer of levator scapulae tendon to the supraspinatus is an option to improve shoulder abduction in posttraumatic brachial plexus. In conditions where supraspinatus alone is not functioning, levator scapulae is the best available transfer, considering its strength and maintaining the form of the shoulder unlike trapezius transfer. In patients with previous surgery where supraspinatus has recovered partially but not functionally significant, this tendon transfer can be considered for the augmentation of the existing shoulder abduction.

Delayed Rehabilitation Protocol after Rotator Cuff Repair

Rotator cuff tears are a frequent cause of shoulder pain that often require arthroscopic repair. After surgery an intense and well-studied rehabilitation protocol is needed to obtain the complete recovery of shoulder function. Fifty patients, who sustained arthroscopic rotator cuff repair for symptomatic, atraumatic and full-thickness supraspinatus tendon tear, were involved. According to our rehabilitation protocol, during the first four postoperative weeks, the arm was supported with an abduction sling pillow, and pendulum exercises, table slide and active elbow extension and flexion were conceded. Outcome measures (Oxford shoulder score (OSS), simple shoulder test (SST), patient-reported satisfaction), shoulder function (range of motion (ROM) and muscle strength), and MRI examination were evaluated. The mean OSS score and SST score increased from 16 to 30.2 and from 5.3 to 11.4, respectively. Patient-reported satisfaction was 96%. At 12 months, patients improved ROM and muscle strength. Postoperative passive anterior elevation was 176; external rotation averaged 47; internal rotation was 90. Postoperative muscle strength during anterior elevation was 8.3 ± 2.2 kg, internal rotation 6.8 ± 3 kg, external rotation 5.5 ± 2.3 kg. Five out of seven patients with recurrent tears evaluated their results as satisfactory. They reported improvements in terms of OSS and SST mean scores despite recurrent tears; therefore, they did not undergo revision surgery. The delayed postoperative physical therapy protocol was associated with improvements in the outcome measures and shoulder function compared to the preoperatory state and rotator cuff healing demonstrated by MRI.

Reproducibility and reliability of performance indicators to evaluate the therapeutic effectiveness of biofeedback therapy after elbow surgery: An observational case series.

Electromyographic biofeedback (EMG-BF) therapy provides information on the state of contraction of the targeted muscles and relaxation of their antagonists, which can facilitate early active range of motion (RoM) after elbow surgery. Our aim in this study was to calculate the minimum detectable change (MDC) during EMG-BF therapy, initiated in the early postoperative period after elbow surgery.This study is an observational case series. EMG-BF of muscle contraction and relaxation was provided during active elbow flexion and extension exercises. Patients completed 3 sets of 10 trials each of flexion and extension over 4 weeks. The total range of flexion-extension motion and scores on the Japanese Society for Surgery of the Hand version of the disability of the arm, shoulder, and hand questionnaire and the Japanese version of the Patient-Rated Elbow Evaluation were obtained at baseline and weekly during the 4-week intervention period. A prediction formula was developed from the time-series data obtained during the intervention period, using the least-squares method. The estimated value was calculated by removing the slope from the prediction formula and adding the initial scores to residuals between the measured scores and predicted scores individually. Systematic error, MDC at the 95th percentile cutoff (MDC95), repeatability of the measures, and the change from the baseline to each time-point of intervention were assessed.The MDC95 was obtained for all 3 outcome measures and the range of values was as follows: RoM, 8.3° to 22.5°; Japanese version of the Patient-Rated Elbow Evaluation score, 17.6 to 30.6 points; and disability of the arm, shoulder, and hand questionnaire subscale: disability and symptoms score, 14.2 to 22.9 points.The efficacy of EMG-BF after elbow surgery was reflected in earlier initiation of elbow RoM after surgery and improvement in patient-reported upper limb function scores. The calculated MDC95 cut-offs could be used as reference values to assess the therapeutic effects of EMG-BF in individuals.

C5/C6 brachial plexus palsy reconstruction using nerve surgery: long-term functional outcomes

IntroductionIn traumatic proximal brachial plexus lesions (i.e., C5/C6), reconstruction of the musculocutaneous, axillary and suprascapular nerves yields satisfactory short- and medium-term functional outcomes. HypothesisEarly functional outcomes after nerve surgery will be maintained in the long-term. MethodsA retrospective analysis was done using the medical records of 29 patients with C5/C6 palsy treated by nerve surgery. Active range of motion and strength at the elbow (i.e., flexion) and shoulder (i.e., flexion, abduction, external rotation with the elbow at the side of the body and with the arm 90° abducted ) were evaluated clinically using a goniometre and the British Medical Research Council grading scale, respectively. ResultsAt a mean follow-up of 46±15 months (25;76), the mean active elbow flexion was 126°±18° (90;150) and the mean strength was 3.8±0.5 (2;4). At the shoulder, mean active flexion, abduction, external rotation with the elbow at the side of the body and with the arm 90° abducted were 109°±39° (0;180), 99°±38° (0;180°), 12°±34° (−80;70) and 3°±21° (−40;50), while mean strength was 3.6±0.8 (0;4), 3.6±0.8 (0;4), 3.4±0.9 (0;4) and 2.5±1.2 (0;4), respectively. DiscussionIn cases of C5/C6 palsy, early nerve surgery yields satisfactory functional outcomes that are maintained over time for elbow flexion and shoulder elevation. However, when the teres minor is not reinnervated, it is difficult to restore satisfactory shoulder external rotation. Level of evidenceIV, Retrospective case study.

Neurophysiological signals for estimation of the result of latissimus dorsii muscle transfer to biceps brachii in patients with arthrogryposis

Background. One of the leading causes of restriction in daily-living activities in patients with arthrogryposis is severe hypoplasia (or aplasia) of the biceps brachii. Latissimus dorsii muscle transfer to the biceps brachii is one of the most used methods for the reconstruction of active elbow flexion in patients with arthrogryposis.
 Aim. The aim of the study is to identify neurophysiological correlates for evaluating the result of the transposition of the latissimus dorsii muscle to the biceps in patients with multiple congenital arthrogryposis.
 Materials and methods. From 2011 to 2018, we performed monopolar latissimus dorsii muscle transfer to the biceps for the restoration of active elbow flexion in 30 patients with arthrogryposis (44 upper extremities). The follow-up results were studied in 14 cases. For this purpose, we used clinical examination, surface electromyography (sEMG), and statistical analysis. The patients were examined before and from 1 month to 96 months (7 months; 224.5 months) after the surgery. The age of patients was from 1 to 10 years at the time of surgery (4.89 2.42 years).
 Results. Our study showed that the age of the child at the time of surgery does not significantly change the index of activation of the latissimus dorsii muscle. A decrease of coactivation of the latissimus dorsii muscle in the long term after surgery correlates with an increase in the strength of the displaced latissimus dorsii muscle, and an improvement in active flexion in the elbow. If the value of the index of coactivation of the latissimus dorsii muscle is less 42%, the muscle strength after surgery reaches 4 points. It was found that the index of coactivation of the latissimus dorsii muscle does not depend on the level of segmental damage to the spinal cord. However, the strength of the muscle depends on the level of spinal cord damage.
 Conclusion. The determination of the index coactivation of the latissimus dorsii muscle after surgery can be used to evaluate the results of the latissimus dorsii muscle transfer to the biceps in patients with arthrogryposis. The index of activation of the latissimus dorsii muscle must be less than 42% for effective elbow active flexion.

Bipolar Latissimus Dorsi Transfer for Arthrogryposis Multiplex Congenita: Minimum 10-Month Follow-Up

To examine the outcomes of patients who have undergone bipolar latissimus dorsi transfer for loss of elbow flexion in arthrogryposis multiplex congenita (AMC). This study retrospectively evaluated 6 cases (5 patients) of bipolar latissimus dorsi transfer performed to restore active elbow flexion in pediatric patients with AMC. Elbow range of motion and strength were evaluated before and after surgery. Functional outcomes were evaluated by the patients' ability to perform activities of daily living. Complications and patient satisfaction were also evaluated at final follow-up. The patients were a mean age of 7.8 ± 3 years. The mean follow-up was 30.2 months (range, 10-44 months). At most recent follow-up, all cases reported improved function of the surgical extremity when performing activities of daily living and overall satisfaction. The postoperative active range of motion was 76° ± 14°. All cases had active elbow flexion against gravity. One patient was noted to have decreased muscle activation of the transfer 6 months after surgery, but strength improved by the 10-month follow-up. No other complications were noted. We recommend bipolar latissimus dorsi transfer as a reliable option to restore functional elbow flexion in patients with AMC. Meticulous pedicle handling and assessment of the latissimus dorsi viability is paramount. Therapeutic V.

The role of biceps loading and muscle activation on radial head stability in anterior Monteggia injuries: An in vitro biomechanical study

IntroductionLittle evidence-based information is available to direct the optimal rehabilitation of patients with anterior Monteggia injuries. Purpose of the StudyThe aims of this biomechanical investigation were to (1) quantify the effect of biceps loading and (2) to compare the effect of simulated active and passive elbow flexion on radial head stability in anterior Monteggia injuries. Study DesignIn vitro biomechanical study. MethodsSix cadaveric arms were mounted in an elbow motion simulator. The effect of biceps loading, simulated active and passive elbow flexion motions was examined with application of 0N, 20N, 40N, 60N, 80N, and 100N of load. Simulated active and passive elbow flexion motions were then performed with the forearm supinated. Radial head translation relative to the capitellum was measured using an optical tracking system. After testing the intact elbows, the proximal ulna was osteotomized and realigned using a custom jig to simulate an anatomical reduction. We then sequentially sectioned the anterior radiocapitellar joint capsule, annular ligament, quadrate ligament, and the proximal and middle interosseous membrane to simulate soft tissue injuries commonly associated with anterior Monteggia fractures. ResultsGreater magnitudes of biceps loading significantly increased anterior radial head translation. However, there was no significant difference in radial head translation between simulated active and passive elbow flexion except in the final stage of soft tissue sectioning. There was a significant increase in anterior radial head translation with progressive injury states with both isometric biceps loading and simulated active and passive motion. ConclusionsOur results demonstrate that anatomic reduction of the ulna may not be sufficient to restore radial head alignment in anterior Monteggia injuries with a greater magnitude of soft tissue injury. In cases with significant soft tissue injury, the elbow should be immobilized in a flexed and supinated position to allow relaxation of the biceps and avoid movement of the elbow in the early postoperative period.

Deficits in corticospinal control of stretch reflex thresholds in stroke: Implications for motor impairment

ObjectivesThe corticospinal system (CS) regulates muscle activation through shifts in muscle-level tonic stretch-reflex thresholds (TSRT). This ability is impaired in stroke and contributes to sensorimotor impairments such as spasticity. We determined the role of CS in elbow flexor activity regulation in healthy and post-stroke subjects. We also determined whether CS modulation deficits were related to sensorimotor impairment intensity in post-stroke individuals. MethodsSeventeen healthy (59.8 ± 12.2 yr) and 27 stroke subjects (58.7 ± 10.1 yr) had transcranial magnetic stimulation (TMS) applied over the primary motor cortex (M1) flexor representation to elicit motor-evoked potentials (MEPs) in elbow flexors in different angular positions. In a subset of post-stroke subjects (n = 12), flexor TSRTs were measured in passive and active conditions, and TSRT modulation was determined. ResultsPosition-related MEP amplitude modulation was similar in healthy and mild stroke subjects, while subjects with more severe stroke exhibited less consistent modulation. MEP modulation in stroke was related to clinical upper limb motor impairment, spasticity, and the ability to modulate TSRTs between passive and active elbow movements. ConclusionsCS output was closely related to TSRT modulation. Impairments in TSRT regulation may underlie motor deficits in moderate-to-severe post-stroke individuals. SignificanceTranslation of these neurophysiological findings to clinical applications may enhance post-stroke motor recovery.

Restoration of Elbow Flexion With a Free Functional Gracilis Muscle Transfer in an Arthrogrypotic Patient Using a Motor Nerve to Pectoralis Major.

Background: Patients with arthrogryposis may exhibit inability to flex the elbow. A free functional gracilis muscle transfer (FFGMT) can be used to restore elbow flexion. In our search of the available literature, we have not seen any descriptions of using a motor branch to the pectoralis major as a donor nerve to establish elbow flexion. Methods: We performed an FFGMT for restoration of elbow flexion in an arthrogrypotic patient with no active elbow flexion, who had a Medical Research Council (MRC) muscle grade of 0. Results: We report our 4.5-year outcomes. After undergoing an FFGMT for elbow flexion, our patient was able to gain an MRC grade 4 and achieve an arc of motion of 25° to 140°. Conclusion: An FFGMT for elbow flexion may be performed successfully using a motor branch to the pectoralis major.

Comparative Clinical Outcomes of Reverse Total Shoulder Arthroplasty for Primary Cuff Tear Arthropathy Versus Severe Glenohumeral Osteoarthritis With Intact Rotator Cuff: A Matched-Cohort Analysis.

The purpose of this study was to compare the short- to mid-term outcomes of patients who underwent reverse total shoulder arthroplasty (RTSA) for severe glenohumeral osteoarthritis (GHOA) with an intact rotator cuff (RC) to a matched rotator cuff arthropathy (RCA) cohort. Between 2004 and 2014, all patients who underwent RTSA for severe GHOA with a minimum 2-year follow-up were identified. Demographic and baseline variables were extracted from the medical records. Subjects were matched in the ratio of 1:2 to RTSA subjects with RCA, while controlling for the demographic and intraoperative variables. Postoperative active forward elevation (AFE), active external rotation, American Shoulder and Elbow Surgeons Score (ASES), Visual Analog Scale (VAS), and Simple Shoulder Test were recorded. Complications and revision surgery rates were noted. Comparative multivariate analysis was performed. Preoperative Walch classification for each subject was obtained through radiograph review, and the impact of classification was assessed using one-way analysis of variance testing. One hundred thirty-six patients were available with mean follow-up 32.3 ± 12.3 months. Baseline range of motion and patient reported outcome scores were similar between the groups (P > 0.05), except for Simple Shoulder Test (intact rotator cuff: 5.7 ± 7.4 versus RCA: 2.4 ± 1.8, P = 0.037). The intact RC group had significantly, superior absolute outcome measures for active external rotation (P = 0.006), and SST (P = 0.048), but not for SANE (P = 0.055), VAS (P = 0.464), ASES (P = 0.084), and AFE (P = 0.099). No notable difference was observed between the groups for improvement in motion, survey scores, or complications. Walch osteoarthritis classification did not impact the outcome measurements in the severe GHOA with the intact RC group (P > 0.05). Patients who underwent RTSA for severe GHOA with intact RC demonstrate similar consistent improvement in outcomes to demographically similar patients with RCA. The severity of GHOA defined by the Walch classification did not impact the outcomes at the 2-year follow-up. Level III Therapeutic Study.

Spastic co-contraction is directly associated with altered cortical beta oscillations after stroke

ObjectiveSpastic co-contraction is a motor-disabling form of muscle overactivity occurring after a stroke, contributing to a limitation in active movement and a certain level of motor impairment. The cortical mechanisms underlying spastic co-contraction remain to be more fully elucidated, the present study aimed to investigate the role of the cortical beta oscillations in spastic co-contraction after a stroke. MethodWe recruited fifteen post-stroke participants and nine healthy controls. The participants were asked to perform active elbow extensions. In the study, multimodal analysis was performed to combine the evaluation of three-dimensional elbow kinematics, the elbow muscles electromyographic activations, and the cortical oscillatory activity. ResultsThe movement-related beta desynchronization was significantly decreased in post-stroke participants compared to healthy participants. We found a significant correlation between the movement-related beta desynchronization and the elbow flexors activation during the active elbow extension in post-stroke participants. When compared to healthy participants, post-stroke participants exhibited significant alterations in the elbow kinematics and greater muscle activation levels. ConclusionsCortical beta oscillation alterations may reflect an important neural mechanism underlying spastic co-contraction after a stroke. SignificanceMeasuring the cortical oscillatory activity could be useful to further characterize neuromuscular plasticity induced by recovery or therapeutic interventions.

Transverse Anterior Approach to the Elbow for Pediatric Displaced Lateral Humeral Condyle Fractures.

The anterior approach to the elbow for pediatric lateral condyle fractures (LCF) would provide a better visualization of the articular fracture resulting in better functional results, less complications and a more cosmetically-appealing scar than usually seen with the lateral approach. Retrospective study of children undergoing an open reduction and internal fixation of a displaced LCF via an anterior approach with a transverse incision. Bilateral elbow range of motion (ROM), upper limb alignment and complications were registered. A 4-point ordinal Likert-type scale was employed for parents to rate their level of satisfaction with the cosmetic appearance of the scar. Eighteen children of mean age 76 months (range 27 to 101 months) were included. Fractures were classified as Jackob's Type II in 14 cases and Milch's type II in all cases. Mean follow-up was 12 (range 4 to19) months.Successful condral fracture visualization and reduction was achieved in every case. No intra-operative or post-operative complications occurred. In all cases bone union was obtained 4 to 5 weeks after surgery and at final follow-up, active elbow ROM of at least 90%, was obtained. All parents claimed to be "very satisfied" with their child's scar. A lateral spur was identified in 66.7% o patients. The anterior approach to the elbow was both a feasible and safe allowing full anatomical cartilage reduction. Complications after this technique might decrease compared to the lateral approach but need future comparative studies. The rate of lateral spur did not decreased. Cosmetic scar results seem to be a clear advantage of this approach compared to the classical lateral approach.

The Inverted Free Functioning Gracilis Muscle Transfer For Restoration of Elbow Flexion Following Delayed Presentation or Failed Primary Nerve Reconstruction of Upper Trunk Injuries.

Free functional gracilis transfer is a well-established technique for restoring active elbow flexion in brachial plexus injuries following delayed presentation or failed nerve reconstruction procedures. In cases of delayed presentation or failed nerve reconstruction following upper trunk injuries, the lower trunk intraplexal median and ulnar nerves are spared, thereby making them available to reinnervate the transferred gracilis. Therefore, we have inverted the conventional free functional gracilis orientation so as to orient the flap's recipient nerve in closer proximity to donor median or ulnar nerve fascicles to enable a short, tension-free coaptation in the middle to distal arm. Herein is our descriptive surgical technique for performing an inverted free functional gracilis muscle transfer in order to restore elbow flexion in the setting of an upper trunk injury.

Impact of the EMG normalization method on muscle activation and the antagonist-agonist co-contraction index during active elbow extension: Practical implications for post-stroke subjects

Electromyographic (EMG) raw signals are sensitive to intrinsic and extrinsic factors. Consequently, EMG normalization is required to draw proper interpretations of standardized data. Specific recommendations are needed regarding a relevant EMG normalization method for participants who show atypical EMG patterns, such as post-stroke subjects. This study compared three EMG normalization methods (“isometric MVC”, “isokinetic MVC”, “isokinetic MVC kinematic-related”) on muscle activations and the antagonist-agonist co-contraction index. Fifteen post-stroke subjects and fifteen healthy controls performed active elbow extensions, followed by isometric and isokinetic maximum voluntary contractions (MVC). Muscle activations were obtained by normalizing EMG envelopes during active movement using a reference value determined for each EMG normalization method. The results showed no significant difference between the three EMG normalization methods in post-stroke subjects on muscle activation and the antagonist-agonist co-contraction index. We highlighted that the antagonist-agonist co-contraction index could underestimate the antagonist co-contraction in the presence of atypical EMG patterns. Based on its practicality and feasibility, we recommend the use of isometric MVC as a relevant procedure for EMG normalization in post-stroke subjects. We suggest combined analysis of the antagonist-agonist co-contraction index and agonist and antagonist activations to properly investigate antagonist co-contraction in the presence of atypical EMG patterns during movement.

Transfer of the rhomboid nerve for restoration of shoulder external rotation in partial brachial plexus palsy

Restoration of shoulder external rotation in partial brachial plexus palsies is a real challenge. The transfer of the spinal accessory nerve to the suprascapular nerve remains the gold standard. This transfer, however, cannot be always performed. Therefore, in these cases, we previously proposed the transfer of the rhomboid nerve to the suprascapular nerve through a posterior approach. The goal of the present study is to assess this technique through a short series.Eight male patients had a partial plexus palsy. Five patients had C5, C6 root injuries, two patients had C5, C6, C7 root injuries, and one patient had C5 to C8 root injuries. No patients had C5 or C6 root avulsions. In one patient, the spinal accessory nerve was injured and in seven patients, the proximal suprascapular nerve was not available. All patients underwent a transfer from the rhomboid nerve to the suprascapular nerve. Concerning shoulder elevation, transfers from the branch of the long head of the triceps or ulnar nerve fascicle were transferred to the axillary nerve. For elbow flexion, fascicles from the ulnar nerve, median nerve, or both were used. For elbow extension, three intercostal nerves in one patient and one fascicle from the ulnar nerve in two patients were transferred to the branch of the long head of the triceps. For wrist and finger extension, palliative surgery was proposed.All patients recovered external shoulder rotation (from 70–110º) and shoulder elevation (range, 80–140º). Active elbow flexion was coded M4 in seven patients and M3 in one patient. All patients recovered active elbow extension.The transfer of the rhomboid nerve to the suprascapular nerve is an efficient procedure for shoulder external rotation in partial brachial plexus palsies without C5 root avulsion. The results in terms of range-of-motion are, however, poorer than with the spinal accessory nerve. Therefore, this technique is appropriate if the spinal accessory nerve is injured or if the suprascapular nerve is not available in the cervical area. This technique must be associated with another transfer to the axillary nerve for shoulder elevation. The study of more patients will be necessary to confirm these results.

Effect of ulnar angulation and soft tissue sectioning on radial head stability in anterior Monteggia injuries: an in vitro biomechanical study

Radial head instability continues to be a challenge in the management of anterior Monteggia injuries; however, there is a paucity of literature on the factors that contribute to this instability. The aim of this biomechanical investigation was to examine the effects of ulnar angulation and soft tissue insufficiency on radial head stability in anterior Monteggia injuries. Six cadaveric arms were mounted in an elbow motion simulator. Radial head translation was measured during simulated active elbow flexion with the forearm supinated. After testing the elbows in the intact state, the ulna was osteotomized and tested at 0°, 10°, 20°, and 30° of extension angulation. To examine the effect of soft tissue insufficiency, the anterior radiocapitellar joint capsule, annular ligament, quadrate ligament, and the proximal and middle interosseous membrane (IOM) were sequentially sectioned. There was a significant increase in anterior radial head translation with greater ulnar extension angulation. Sequential soft tissue sectioning also significantly increased anterior radial head translation. There was no increase in radial head translation with isolated sectioning of the anterior radiocapitellar joint capsule. Additional sectioning of the annular ligament and quadrate ligament slightly increased anterior radial head translation but did not reach statistical significance. Subsequent sectioning of the proximal and middle IOM resulted in significant increases in anterior radial head translation. Our study demonstrates that progressive ulnar extension angulation results in an incremental increase in anterior radial head translation in anterior Monteggia injuries. Moreover, increasing magnitudes of soft tissue disruption result in greater anterior radial head instability.

Design Optimization of a Novel Networked Electromagnetic Soft Actuators System Based on Branch and Bound Algorithm

This paper presents a design optimization framework based on Branch and Bound Algorithm for novel networked electromagnetic soft actuators. The soft actuators work based on the operating principle of solenoids but are made of intrinsically soft materials. We confirmed that by scaling down the size of the soft actuators, their force to volume ratio increases. This suggests that by miniaturizing the actuators size and attaching them as a network based on the arrangement of actin and myosin filaments in skeletal muscles, the output force can be enhanced. In order to achieve the maximum output force, design parameters of a single soft actuator as well as those of a network are considered as design variables. The maximum available volume (thickness, width and length) and deflection range of the network are considered design constraints. The cost function, i.e. the output force is a non-linear mixed-integer function. A Branch and Bound optimization algorithm based on interval analysis is then proposed to solve the optimization problem. Numerical simulations are presented for a representative example of an active soft brace for the human elbow joint. The results suggest that an electromagnetic soft actuator network can provide sufficient torque to be used as a drive train for an active elbow brace for both flexion and extension over a range of around 93 degrees.