Review and comparison of linear algorithms to quantify muscle fatigue based on sEMG signals.

Surface electromyography techniques are widely used in field of motion analysis and ergonomics combining precise muscular activation assessment with low-invasiveness and wearability. The aim of this investigation is to identify the myoelectrical manifestations of fatigue and to compare the effectiveness of sEMG-based quantitative indices for fatigue assessment. The investigated indexes are the ARV and RMS signal amplitudes, the mean frequency, the median frequency, the Dimitrov index, the instantaneous mean frequency and Wavelet distribution-based WIRE51 index. Two different protocols were developed, and the activity of the lateral deltoid and middle trapezius muscles was recorded. The WIRE51 index is found to have the highest sensitivity in the detection of the difference between the repetitions of each exercise for both protocols. Due to the lack of a unified standard for the performance comparison of fatigue indices, a correlation analysis was carried out between the result provided by the indices and the subjective fatigue perception employing the RPE scale.

The aim of this study is to compare quantitative indices for assessing muscular fatigue from the sEMG acquisitions. The assessment is accomplished with an experimental investigation of ten subjects and two repetitive movement types. The best performing indices are found to be the WIRE51 and the Dimitrov ones.

Phrenic Nerve as an Alternative Donor for Nerve Transfer to Restore Shoulder Abduction in Severe Multiple Root Injuries of the Adult Brachial Plexus.

PURPOSE: Nerve transfer is the gold standard to restore shoulder abduction in acute brachial plexus injuries. The aim of this study was to compare the phrenic nerve (Ph) to the spinal accessory nerve (XI) as the donor nerve for this purpose. METHODS: A retrospective chart review was performed on 136 patients with acute brachial plexus injuries who received a nerve transfer of the shoulder with either the Ph (94 patients) or XI (42 patients). Each group was divided into 3 subgroups based on the recipient nerve. The maximum degree of shoulder abduction was recorded after 2 years of postoperative follow-up. A generalized estimating equation model was performed to examine the variables affecting shoulder abduction over time. RESULTS: The maximum degrees of shoulder abduction achieved were 61.9° ± 38.7° in patients with Ph and 51.1° ± 37.3° in patients with XI. More than M3 shoulder abduction was achieved by 67% of patients with Ph versus 59% of patients with XI. The regression analysis showed that the age at the time of surgery correlated more with the functional outcome over time than the choice of donor nerve. CONCLUSIONS: In multiple root brachial plexus injuries, the Ph exhibited similar outcomes to the XI for shoulder abduction. Our routine exploration of the supraclavicular plexus exposes the Ph conveniently for nerve transfer. The phrenic nerve should be considered as an alternative when the XI is not available or is reserved for secondary reconstruction. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Acromiohumeral distance changes with posture in healthy adults and patients while wearing a shoulder abduction brace.

[Purpose] To examine the humeral head positions while wearing an abduction brace in the sitting and supine positions in healthy adults and patients who have been operated on for shoulder joint diseases. [Participants and Methods] Thirty participants were included in the study, of which 15 were healthy adults (without any orthopedic diseases) and 15 had shoulder diseases (post-arthroscopic repair of a rotator cuff tear). The acromion and humeral head were observed on ultrasound. The acromiohumeral distance was measured once in two different positions while wearing the brace: edge sitting and supine. [Results] The mean acromiohumeral distance in the healthy group was 7.9 ± 1.1 mm while sitting and 7.2 ± 1.0 mm in the supine position. In the disease group it was 7.6 ± 0.9 mm while sitting and 6.3 ± 1.1 mm in the supine position. Multiple logical regression revealed that the acromiohumeral distance was not affected by the participant's age, height, or weight. [Conclusion] The acromiohumeral distance was significantly reduced in the supine position despite the use of an abduction brace. Therefore, patients must use a pillow/towel to support the shoulder joint to prevent unnecessary stress while the cuff tendons are healing.

Upper extremity nerve transfers for acute flaccid myelitis: a systematic literature review.

BACKGROUND: Acute flaccid myelitis (AFM) is a rare disease that commonly affects young children. AFM's pathophysiology involves loss of lower motor neurons following a viral infection and induces acute asymmetric flaccid paralysis most commonly in the upper extremities. Nerve transfers have emerged as a treatment option for these patients with permanent motor deficits. OBJECTIVE: To summarize the literature and report safety and efficacy outcomes following nerve transfers for recovery of shoulder abduction and external rotation, and elbow flexion and extension in pediatric patients with AFM. Recovery of at least antigravity function was defined as a successful outcome. This systematic review was performed according to the PRISMA guidelines. The PubMed, Embase and Cochrane databases were utilized. RESULTS: Five studies comprising 44 patients (median age 2.95 years; 71% male), and 93 upper extremity nerve transfers were included. Thirty-eight patients received 65 nerve transfer procedures aiming for recovery of shoulder abduction and/or external rotation with a transfer to the axillary and/or suprascapular nerve. The recovery of shoulder abduction and external rotation was achieved in 40.7% (n = 11/27) and 60% (n = 6/10) of patients, respectively. Time from injury to surgery showed an inverse relationship with the odds for successful recovery (OR: 0.81; 95% CI: 0.64-1.02; p = 0.07); however, statistical significance was not reached. Successful recovery of elbow flexion with a transfer to the musculocutaneous was reported at a rate of 92.3% (n = 12/13). Successful re-innervation of the radial nerve with recovery of elbow extension was found in 75% (n = 6/8) of patients. No complications were reported. CONCLUSIONS: Upper extremity nerve transfers appear to be promising and safe for AFM patients. Shoulder abduction is the most challenging upper extremity function to recover. Further studies are warranted to identify whether nerve transfers are associated with superior outcomes when performed earlier.

Possible donor nerves for axillary nerve reconstruction in dual neurotization for restoring shoulder abduction in brachial plexus injuries: a systematic review and meta-analysis.

Restoring shoulder abduction is one of the main priorities in the surgical treatment of brachial plexus injuries. Double nerve transfer to the axillary nerve and suprascapular nerve is widely used and considered the best option. The most common donor nerve for the suprascapular nerve is the spinal accessory nerve. However, donor nerves for axillary nerve reconstructions vary and it is still unclear which donor nerve has the best outcome. The aim of this study was to perform a systematic review on reconstructions of suprascapular and axillary nerves and to perform a meta-analysis investigating the outcomes of different donor nerves on axillary nerve reconstructions. We conducted a systematic search of English literature from March 2001 to December 2020 following PRISMA guidelines. Two outcomes were assessed, abduction strength using the Medical Research Council (MRC) scale and range of motion (ROM). Twenty-two studies describing the use of donor nerves met the inclusion criteria for the systematic review. Donor nerves investigated included the radial nerve, intercostal nerves, medial pectoral nerve, ulnar nerve fascicle, median nerve fascicle and the lower subscapular nerve. Fifteen studies that investigated the radial and intercostal nerves met the inclusion criteria for a meta-analysis. We found no statistically significant difference between either of these nerves in the abduction strength according to MRC score (radial nerve 3.66 ± 1.02 vs intercostal nerves 3.48 ± 0.64, p = 0.086). However, the difference in ROM was statistically significant (radial nerve 106.33 ± 39.01 vs. intercostal nerve 80.42 ± 24.9, p < 0.001). Our findings support using a branch of the radial nerve for the triceps muscle as a donor for axillary nerve reconstruction when possible. Intercostal nerves can be used in cases of total brachial plexus injury or involvement of the C7 root or posterior fascicle. Other promising methods need to be studied more thoroughly in order to validate and compare their results with the more commonly used methods.

Altered muscle recruitment patterns during isometric shoulder abduction in individuals with chronic upper trapezius pain: a cross sectional study.

BACKGROUND: Upper trapezius (UT) pain with myofascial trigger points (MTrPs) can affect movement at the glenohumeral joint as well as at the scapulothoracic joint. The investigation of muscle recruitment patterns can discern motor control strategies. The purpose of this study was to compare shoulder muscle recruitment patterns and muscle activity according to various loads between individuals with and without chronic UT pain. METHODS: In this cross-sectional study, twenty-four participants that had UT pain with MTrPs and sex, age, body weight matched 24 controls with no UT pain were recruited. Surface EMG electrodes were attached to the UT, the serratus anterior (SA), the lower trapezius (LT) and the middle deltoid (MD). All participants performed isometric shoulder abduction with a load of 25%, 50%, or 75% of the maximum strength at 60° of shoulder abduction. The EMG activity, the activity ratio (SA/UT, LT/UT, MD/UT), and the relative contribution of each muscle activity were calculated. RESULTS: MD activity was significantly decreased in the UT pain group compared to that in the control group (p < 0.05). The EMG activity ratio of SA/UT (p < 0.025) and the relative contribution of SA activity to shoulder abduction (p < 0.05) were significantly greater in the UT pain group than in the control group in the 25% loading condition. CONCLUSION: The results of present study showed that UT pain with MTrPs may increase the relative contribution of SA activity and decrease MD activity at low loads. Altered recruitment patterns of scapular upward rotators can be altered in the proper scapular position, which results in decreased MD activity. Clinicians should consider altered recruitment patterns when managing UT pain. TRIAL REGISTRATION: Clinical Research Information Service: Clinical Research Information Service (KCT0007370; 08/06/2022).

A biomechanical study on the effect of long head of biceps tenotomy on supraspinatus load and humeral head position during shoulder abduction.

INTRODUCTION: The purpose of this study was to determine the effect of biceps tendon tenotomy on the load of the supraspinatus tendon/muscle complex during abduction of the arm from 0° to 15°. METHODS: Eleven fresh frozen human cadaver shoulders (6 males, 5 females, age ranged 44-88 years, mean upper extremity weight 2.96 ± 0.56 kg) were included. The specimens were sequentially mounted onto a custom-made fixture attached to a pulley system and load cell. The pulley system was used to pull the supraspinatus tendon/muscle complex along its fiber directions to abduct the arm to 15°. Abduction angles were recorded with a digital inclinometer. Two conditions were tested: (1) long head biceps tendon (LHBT) intact and in normal anatomical position; (2) LHBT cut within the bicipital groove. Qualitative visual inspection of humeral head displacement during abduction was also included. Descriptive statistics were calculated. The Shapiro-Wilk test was used to establish normal data distribution, and the paired t-test was used to compare the 2 conditions. RESULTS: For the intact condition (LHBT intact), the mean load was 45.71 ± 21.04 N. For the biceps tenotomy test, the load measured 41.37 ± 23.43 N. These differences were not significant (P = .1480). In the tenotomy condition, the humeral head initially displaced inferior, and with initiation of abduction, the humeral head translated superior to its normal position. CONCLUSION: The results suggest that the LHBT has no critical role with initial abduction of the arm. Furthermore, the LHBT does not appear to increase loads required for the supraspinatus muscle/tendon complex to perform the same action of abduction.

Teres major transfer to restore external rotation of shoulder in Erb palsy patients.

BACKGROUND: The lack of external rotation and shoulder abduction as sequelae of obstetric brachial plexus palsy requires a release of the subscapularis muscle associated with tendon transfer of the internal rotator of the shoulder. The aim of this study was to present the results of a teres major transfer to the infraspinatus tendon. METHODS: This study included 20 patients (9 boys and 11 girls) with a mean age of 3 years 8 months (range, 1.5-14 years). The average follow-up time was 42 months (range, 12-48 months) to determine whether external rotation weakness and internal rotation contracture sequelae were managed by anterior release of the subscapularis and teres major tendon transfer to the infraspinatus tendon. RESULTS: We found marked improvement in shoulder abduction from 67° before surgery to 158° after surgery. We also found marked improvements in active external rotation from 8° before surgery to 85° after surgery and in passive external rotation from 0° preoperatively to 72° postoperatively. Two cases showed a loss of the last degrees of internal rotation, but this improved after physiotherapy. CONCLUSIONS: Anterior release of the subscapularis tendon with a teres major transfer to the infraspinatus tendon significantly improves shoulder function in Erb palsy patients with internal rotation contracture.

The extent of brachial plexus injury: an important factor in spinal accessory nerve to suprascapular nerve transfer outcomes.

Objective: The purpose of this study was to assess the association between extent of brachial plexus injury and shoulder abduction/external rotation outcomes after spinal accessory nerve (SAN) to suprascapular nerve (SSN) transfer.Methods: A systematic review of the literature was conducted according to PRISMA guidelines. Inclusion criteria were studies reporting outcomes on patients undergoing SAN to SSN nerve transfer. Patients were excluded for the following reasons: age under 18, nerve transfer for reanimation of the shoulder other than SAN to SSN, and less than 12 months of follow-up postoperatively. Pooled analysis was performed, and primary outcomes were Medical Research Council (MRC) score and range of motion (ROM) for shoulder abduction and external rotation. Univariate logistic regression analysis was used to assess the association between extent of brachial plexus injury and shoulder abduction/external rotation outcomes after SAN to SSN transfer. A multivariate logistic regression analysis model including age, injury to surgery interval, and extent of injury as factors was also created.Results: Univariate logistic regression analysis showed greater extent of injury to be a predictor of poorer shoulder abduction outcomes (OR: 0.502; 95% CI: 0.260-0.971, p = 0.040). Multivariate logistic regression analysis confirmed this association (OR: 0.55; 95% CI: 0.236-0.877, p = 0.019). Extent of injury was not significantly associated with external rotation outcomes on univariate analysis (OR: 0.435; 95% CI: 0.095-1.995, p = 0.284) or multivariate analysis (OR: 0.445; 95% CI: 0.097-2.046, p = 0.298). Age and injury to surgery interval were not significantly associated with postoperative outcomes.Conclusions: More extensive brachial plexus injuries are associated with inferior outcomes after SAN to SSN transfer. A potential explanation for this finding includes lost contribution of muscles from the shoulder girdle that receive innervation from outside of the upper brachial plexus. The relationship between extent of injury and postoperative outcomes is important to recognize when determining and discussing operative intervention with patients.

Comparative study of single and dual nerve transfers for repairing shoulder abduction.

OBJECTIVE: The purpose of this study was to compare the effects of single and dual nerve transfer for the repair of shoulder abduction in patients with upper or upper and middle trunk root avulsion. METHODS: We carried out a retrospective analysis of 20 patients with C5-C6 or C5-C7 root avulsion treated by nerve transfer in our hospital. The patients were divided into two groups according to the different operation methods. In group A, ten patients had transferred the spinal accessory nerve to the suprascapular nerve. Ten patients in group B underwent dual nerve transfer to reconstruct shoulder abduction, including the spinal accessory nerve transfer to the suprascapular nerve and two intercostal nerves or the long head of triceps nerve branch transfer to the anterior branch of the axillary nerve. There was no difference in age, preoperative interval, follow-up time, and injury type between the two groups. We used shoulder abduction strength, shoulder abduction angle, and Samardzic's shoulder joint evaluation standard as the postoperative evaluation index. Shoulder abductor muscle strength equals or above M3 was considered to be an effective recovery. RESULTS: Of the 20 cases, 15 obtained equals or more M3 of shoulder abduction strength, and the overall effective rate was 75%. The effective rate of shoulder abduction power in group A was 60% (6/10) while group B was 90% (9/10); however, the difference was not statistically significant (p > 0.05). The average shoulder abduction angle was 55° (SD = 19.29) in group A and 77° (SD = 20.44) in group B; the angle was significantly better in group B than that in group A (p < 0.05). Based on Samardzic's standard, the excellent and good rate of group A was 90% and in group B was 50%. The difference was statistically significant (p < 0.05). CONCLUSION: For patients with nerve root avulsion of C5-C6 or C5-C7, repairing suprascapular nerve and axillary nerve at the same time is more effective than repairing suprascapular nerve alone in terms of shoulder abduction angle and excellent rate of functional recovery of the shoulder joint. Therefore, we recommend the repair of the suprascapular nerve and the axillary nerve simultaneously if conditions permit.

Comparison of the trapezius and serratus anterior muscles isolation ratio during different shoulder abduction exercises.

[Purpose] To measure the activities of the upper, middle, and lower trapezius and serratus anterior muscles during shoulder abduction at two angles and compare their relative isolation. [Subjects and Methods] Ten men were enrolled. The tester measured the isolation ratios of upper, middle, and lower trapezius and serratus anterior muscles during shoulder abduction exercises at 60° and 120°. [Results] Neither the upper nor the lower trapezius isolation ratios differed statistically between 60° and 120°. The middle trapezius showed higher isolation ratio at 60° than at 120°. The serratus anterior showed higher isolation ratio at 120° than at 60°. [Conclusion] The upper, lower, and middle trapezius can be strengthened sufficiently with exercises at a low range of angles.

Same-session and between-day intra-rater reliability of hand-held dynamometer measurements of isometric shoulder extensor strength.

[Purpose] The purpose of present study was to establish the same-session and between-day intra-rater reliability of measurements of extensor strength in the maximum abducted position (MABP) using hand-held dynamometer (HHD). [Subjects] Thirteen healthy volunteers (10 male, 3 female; mean ± SD: age 19.8 ± 0.8 y) participated in the study. [Methods] Participants in the prone position with maximum abduction of shoulder were instructed to hold the contraction against the ground reaction force, and peak isometric force was recorded using the HHD on the floor. Participants performed maximum isometric contractions lasting 3 s, with 3 trials in one session. Between-day measurements were performed in 2 sessions separated by a 1-week interval. Intra-rater reliability was determined using intraclass correlation coefficients (ICC). Systematic errors were assessed using Bland-Altman analysis for between-day data. [Results] ICC values for same-session data and between-day data were found to be "almost perfect". Systematic errors not existed and only random error existed. [Conclusion] The measurement method used in this study can easily control for experimental conditions and allow precise measurement because the lack of stabilization and the impact of tester strength are removed. Thus, extensor strength in MABP measurement is beneficial for muscle strength assessment.

Intra- and inter-rater reliability of isometric shoulder extensor and internal rotator strength measurements performed using a hand-held dynamometer.

[Purpose] The purpose of the present study was to establish the intra- and inter-rater reliability of measurement of extensor strength in the maximum shoulder abducted position and internal rotator strength in the 90° abducted and the 90° external rotated position using a hand-held dynamometer. [Subjects and Methods] Twelve healthy volunteers (12 male; mean ± SD: age 19.0 ± 1.1 years) participated in the study. The examiners were two students who had nonclinical experience with a hand-held dynamometer measurement. The examiners and participants were blinded to measurement results by the recorder. Participants in the prone position were instructed to hold the contraction against the ground reaction force, and peak isometric force was recorded using the hand-held dynamometer on the floor. Reliability was determined using intraclass correlation coefficients. [Results] The intra- and inter-rater reliability data were found to be "almost perfect". [Conclusion] This study investigated intra- and inter-rater reliability and reveald high reliability. Thus, the measurement method used in the present study can evaluate muscle strength by a simple measurement technique.

Shoulder position increases ulnar nerve strain at the elbow of patients with cubital tunnel syndrome.

BACKGROUND: Previous studies have shown that the shoulder internal rotation elbow flexion (SIREF) test, which is a modified elbow flexion (EF) test, has significantly higher sensitivity than the EF test in patients with cubital tunnel syndrome (CubTS). Here, we hypothesized that this increase in sensitivity was due to increase in the ulnar nerve strain around the elbow introduced by the additional shoulder position. METHODS: Ulnar nerve strain at the elbow was intraoperatively measured at both the EF test and SIREF test positions in 20 patients with CubTS before simple decompression. Statistical analysis was performed with the Wilcoxon signed rank test at a confidence level of 99% (P < .001). RESULTS: Mean ulnar nerve strain in the EF test position was 18.9% ± 12.1%, whereas that in the SIREF test position was 24.7% ± 14.0%. Ulnar nerve strain was higher in the SIREF than in the EF test position in all cases, and the difference was significant (mean, 5.8% ± 0.9%; 95% confidence interval, 3.90%-7.73%). CONCLUSION: This study indicated that increased sensitivity in the SIREF test compared with the EF test was due to the increase in ulnar nerve strain around the elbow. To the best of our knowledge, this is the first study showing that shoulder position changes the ulnar nerve strain around the elbow in living patients with CubTS.

Increased horizontal shoulder abduction is associated with an increase in shoulder joint load in baseball pitching.

BACKGROUND: Soft tissues of the shoulder undergoes substantial stresses due to humeral head movement, and this may contribute to throwing shoulder injuries in baseball pitchers. Prevention and management of throwing shoulder injuries critically rely on reduction of shear force at the shoulder joint. However, the amount and direction of the force applied to the shoulder during the throwing motion have not been clarified. The purpose of this study was to analyze forces applied to the shoulder during a baseball pitch. METHODS: We performed biomechanical analysis of 213 baseball pitchers of various ages and skill levels. Throwing motion was analyzed with a 3-dimensional motion capture system. The Euler angle sequence was adopted to describe angular values of the upper arm relative to the trunk for shoulder rotation, and inverse dynamics was used to estimate the resultant joint forces at the shoulder. RESULTS: There was a significant relation between horizontal abduction/adduction angle and resultant anterior/posterior force at the point of maximum external rotation (MER) (r = -0.63, P < .01), whereby increased horizontal abduction was associated with increased resultant anterior force. There was a significant but weak correlation between abduction/adduction angle and superior/inferior force at MER (r = 0.24, P < .01). Comparison among the groups with variable ages and skill levels showed larger horizontal abduction and smaller external rotation angles at MER in the adult amateur player group, whereas normalized compression force and internal rotation torque values at MER were smaller in the junior high school- and elementary school-aged groups. DISCUSSION: These results suggest that excessive horizontal abduction at MER increases anterior shear force in the shoulder and may lead to shoulder injuries. Focusing on reducing horizontal abduction at MER in the throwing motion may be key to preventing and managing shoulder injuries in baseball pitchers.

The value of provocative tests in diagnosis of cervical radiculopathy.

BACKGROUND: This study was aimed at assessing the accuracy of provocative tests in diagnosis of acute or chronic Cervical Radiculopathy (CR) based on an electrodiagnostic reference criterion. MATERIALS AND METHODS: Shoulder Abduction Test (SAT), Spurling Test (ST), Upper Limb Tension Test (ULTT), and electromyography were done on 97 patients who referred to Electrodiagnostic center in the university hospital from January 2010 to March 2011. All of the participants had neck and radicular pain for at least 3 weeks. They were classified according to electrodiagnostic findings. Then diagnostic values of provocative tests were assessed in diagnosis of acute or chronic CR on the basis of reference criterion. RESULTS: SAT and ST were more specific (85%) compared to ULTT, while ULTT was more sensitive (60.46% in acute and 35.29% in chronic) than the other two. SAT and ST had a significant accuracy for comparison between acute and chronic CR (P < 0.05). CONCLUSION: ULTT is suitable for screening of CR, while SAT and ST can support diagnosis. SAT and ST are good diagnostic tests for comparison between acute and chronic CR.

Comparison of Shoulder Muscles Activation for Shoulder Abduction between Forward Shoulder Posture and Asymptomatic Persons.

[Purpose] This study investigated the differences in shoulder muscles activities during shoulder abduction between a forward shoulder posture group and asymptomatic group. [Subjects] Seven males with forward shoulder posture (FHS) and seven asymptomatic males were recruited. [Methods] We measured the upper and middle trapezius (UT and MT), serratus anterior (SA), and clavicle portion of the pectoralis major (cPM) in the right side during shoulder abduction. [Results] The activities of the UT and cPM in the FHS group were significantly more increased when compared with the asymptomatic group. The activities of the MT and SA in the FHS group were significantly more decreased when compared with the asymptomatic group. [Conclusion] We suggest that forward shoulder posture may become a potential risk factor evoking the various shoulder disorders.

Latissimus dorsi tendon transfer to restore shoulder abduction in patients with deltoid paralysis: A novel technique.

Background: Shoulder abduction is an essential movement for placement of the hand in space and thus for upper limb function. The objective of this study was to introduce and test the effectiveness of a new technique of latissimus dorsi tendon transfer to deltoid insertion to restore shoulder abduction. Methods: We prospectively included 10 male patients with a lost deltoid function. Their mean age was 34.6 years (range, 25-46). We describe a new technique to compensate for the loss of the deltoid function using a latissimus dorsi tendon transfer augmented with a semitendinosus tendon graft. The tendon graft is passed over the acromion and attached to the anatomical deltoid insertion. Postoperatively, a shoulder spica in 90° abduction was used for six weeks followed by physiotherapy. Results: Patients were followed up for a mean of 25.4 months (range, 12-48). The mean range of active shoulder abduction rose to 110° (range, 90-140°) with a mean gain of 83° of abduction. Conclusions: This procedure can be a useful technique for restoration of a significant range and strength of active shoulder abduction.

Posterior division of ipsilateral C7 transfer to C5 for shoulder abduction limitation.

Background: Reparation of C5 by proximal selective ipsilateral C7 transfer has been reported for the treatment of neurogenic shoulder abduction limitation as an alternative to the reparation of the suprascapular nerve (SSN) and the axillary nerve (AXN) by distal nerve transfers. However, there is a lack of evidence to support either strategy leading to better outcomes based on long-term follow-up. Objective: The purpose of the study was to investigate the safety and long-term outcomes of the posterior division of ipsilateral C7 (PDIC7) transfer to C5 in treating neurogenic shoulder abduction limitation. Methods: A total of 27 cases with limited shoulder abduction caused by C5 injury (24 cases of trauma, 2 cases of neuritis, and 1 case of iatrogenic injury) underwent PDIC7 transfer to the C5 root. A total of 12 cases (11 cases of trauma and 1 case of neuritis) of C5 injury underwent spinal accessory nerve (SAN) transfer to SSN plus the triceps muscular branch of the radial nerve (TMBRN) transfer to AXN. The patients were followed up for at least 12 months for muscle strength and shoulder abduction range of motion (ROM). Results: In cases that underwent PDIC7 transfer, the average shoulder abduction was 105.9° at the 12-month follow-up. In total, 26 of 27 patients recovered at least M3 (13 reached M4) (Medical Research Council Grading) of the deltoid. In cases that underwent SAN transfer to SSN plus TMBRN to AXN, the average shoulder abduction was 84.6° at the 12-month follow-up. In total, 11 of 12 patients recovered at least M3 (4 reached M4) of the deltoid. Conclusion: Posterior division of ipsilateral C7 transfer is a one-stage, safe, and effective surgical procedure for patients with neurogenic shoulder abduction limitation.

Comparative accuracy of a shoulder range motion measurement sensor and Vicon 3D motion capture for shoulder abduction in frozen shoulder.

BACKGROUND: Although patients with frozen shoulders have the range of motion (ROM) of their shoulder's abduction movements measured at hospital and the physical therapy visits, multiple visits to check for progress is often difficult. Thus, we developed an artificial intelligence-based image recognition detectable sensor (AIRDS) intended for easy use at home. OBJECTIVE: The purpose of this study was to determine the accuracy of a sensor (AIRDS) measuring shoulder abduction angle, thus offering a valid and feasible system for monitoring patients with frozen shoulder. METHODS: Ten patients with frozen shoulder (5 males, 5 females) performed shoulder joint movements while being measured with the AIRDS system and the 3-dimensional Vicon system. The measure of the outcome included the linear regression of the shoulder abduction joint kinematics. RESULTS: Linear regression analysis of the AIRDS system and the Vicon system demonstrated a significant correlation coefficient of R2= 0.9979 (P< 0.05). CONCLUSIONS: Our results provide novel, promising evidence that AIRDS can accurately measure the timing and total spatial characteristics of clinical movements. AIRDS is designed to provide real-time ROM measurements for joint mobility using artificial intelligence instead of the judgement of the physical therapist.