Verification of acromion marker cluster and scapula spinal marker cluster methods for tracking shoulder kinematics: a comparative study with upright four-dimensional computed tomography.

BACKGROUND: This study validated the accuracy of the acromion marker cluster (AMC) and scapula spinal marker cluster (SSMC) methods compared with upright four-dimensional computed tomography (4DCT) analysis. METHODS: Sixteen shoulders of eight healthy males underwent AMC and SSMC assessments. Active shoulder elevation was tracked using upright 4DCT and optical motion capture system. The scapulothoracic and glenohumeral rotation angles calculated from AMC and SSMC were compared with 4DCT. Additionally, the motion of these marker clusters on the skin with shoulder elevation was evaluated. RESULTS: The average differences between AMC and 4DCT during 10°-140° of humerothoracic elevation were - 2.2° ± 7.5° in scapulothoracic upward rotation, 14.0° ± 7.4° in internal rotation, 6.5° ± 7.5° in posterior tilting, 3.7° ± 8.1° in glenohumeral elevation, - 8.3° ± 10.7° in external rotation, and - 8.6° ± 8.9° in anterior plane of elevation. The difference between AMC and 4DCT was significant at 120° of humerothoracic elevation in scapulothoracic upward rotation, 50° in internal rotation, 90° in posterior tilting, 120° in glenohumeral elevation, 100° in external rotation, and 100° in anterior plane of elevation. However, the average differences between SSMC and 4DCT were - 7.5 ± 7.7° in scapulothoracic upward rotation, 2.0° ± 7.0° in internal rotation, 2.3° ± 7.2° in posterior tilting, 8.8° ± 7.9° in glenohumeral elevation, 2.0° ± 9.1° in external rotation, and 1.9° ± 10.1° in anterior plane of elevation. The difference between SSMC and 4DCT was significant at 50° of humerothoracic elevation in scapulothoracic upward rotation and 60° in glenohumeral elevation, with no significant differences observed in other rotations. Skin motion was significantly smaller in AMC (28.7 ± 4.0 mm) than SSMC (38.6 ± 5.8 mm). Although there was smaller skin motion in AMC, SSMC exhibited smaller differences in scapulothoracic internal rotation, posterior tilting, glenohumeral external rotation, and anterior plane of elevation compared to 4DCT. CONCLUSION: This study demonstrates that AMC is more accurate for assessing scapulothoracic upward rotation and glenohumeral elevation, while SSMC is preferable for evaluating scapulothoracic internal rotation, posterior tilting, glenohumeral external rotation, and anterior plane of elevation, with smaller differences compared to 4DCT.

Factors associated with resorption of calcific deposits in the shoulder with extracorporeal shock wave therapy.

BACKGROUND: Focused extracorporeal shock wave therapy (FSWT) is effective for treating calcific tendinitis of the shoulder. However, only a few reports exist on the factors related to calcium resorption after FSWT. Thus, this study aimed to investigate the factors associated with calcium resorption. METHODS: In 117 shoulders with chronic calcific rotator cuff tendinitis, FSWT was administered nine times once every 2 weeks (a total of 16 weeks). After nine sessions of FSWT, the shoulders were radiographed and categorized into complete resorption (CR) and incomplete resorption (ICR) groups. Evaluated parameters included age, duration of disease, Gärtner classification, size of calcium deposits, presence of blood flow around calcium deposits using the Doppler function of the ultrasound imaging system, Japanese Orthopaedic Association (JOA) score, University of California at Los Angeles score, disability of the arm, shoulder, and hand (UCLA) score, and tenderness. RESULTS: The CR group included 93 shoulders (79.4%) and the ICR group included 24 shoulders (20.6%). In the two-arm comparison, CR showed significantly longer disease duration (P=.012) and high tenderness (P=.0013). Blood flow around calcium deposits was observed in 79.5% of shoulders in the CR group (P<.0001) and 29.1% in the ICR group. Type 1 Gärtner classification (P=.0009) was observed in 28 shoulders (30.1%) in the CR group and 17 shoulders (70.8%) in the ICR group. The two groups had no significant differences in age, size of calcium deposits, JOA score, or UCLA score. Multiple logistic regression analysis was performed using the following items that showed significant differences: absence of blood flow (odds ratio [OR], 8.51, 95% confidence interval [CI]: 2.24-22.8), Gärtner classification (OR, 5.60, 95%CI: 1.73-13.3), and duration of disease (OR, 1.06, 95%CI: 0.97-1.26). Longer disease duration, Gärtner type 1, and absence of blood flow around calcium deposits resulted in difficulty in calcium resorption. CONCLUSION: Patients with Gärtner type 1 with prolonged disease duration and absence of blood flow around calcium deposits may have difficulty in achieving complete resorption.

Arthroscopic findings of the glenohumeral joint in symptomatic anterior instabilities: comparison between overhead throwing disorders and traumatic shoulder dislocation.

BACKGROUND: The term shoulder instability refers to a variety of mechanisms and clinical presentations. One of the common pathologies of throwing disorders is internal impingement with anterior instability. Most throwing athletes with symptomatic internal impingement with anterior instability exhibit positive apprehension and relocation test results, whereas those with recurrent anterior shoulder instability display positive apprehension test results. While the glenoid labrum-inferior glenohumeral ligament complex is a significant critical stabilizer for the prevention of anterior shoulder dislocation, the characteristics of the essential lesion in internal impingement with anterior instability have not been determined yet. This study aimed to compare the intra-articular lesion of athletes with internal impingement related to the overhead throwing motion in athletes with a traumatic shoulder dislocation. METHODS: Sixty-one athletes (all men; mean age, 25.2 ± 12.6 yr) who underwent an arthroscopic procedure were divided into 2 groups: 25 in the throwing group and 36 in the dislocation group. All shoulders had subtle glenohumeral instability defined by a positive anterior apprehension test and a relocation test. Those with voluntary and multidirectional instability and large glenoid bone loss (more than 25%) were excluded from the current study. All shoulders were evaluated for the following evidence: rotator cuff injury, superior labrum tear anterior and posterior lesions, labral pathologies including Bankart lesions, osteochondral lesions to the humeral head, biceps tendon fraying or rupture, and inferior glenohumeral ligament and middle glenohumeral ligament (MGHL) conditions. RESULTS: Arthroscopic findings of the throwing group showed more supraspinatus injuries (92% and 25%, P < .001), type II superior labrum tear anterior and posterior lesions (60% and 3%, P < .001), posterosuperior labral lesions (92% and 39%, P < .001), and hypoplastic MGHLs (56% and 6%, P < .001) and lesser Bankart lesions (8% and 92%, P < .05) than those of the dislocation group. CONCLUSIONS: These results indicate that the characteristic lesions of internal impingement with anterior instability in throwing athletes include partial thickness rotator cuff tears, superior labrum tear anterior and posterior lesions, posterosuperior labral tears, and hypoplastic MGHLs. As expected, the physiopathology of internal impingement with anterior instability in throwing athletes may be related to the dysfunction of the anterosuperior glenohumeral capsular ligament, including the MGHL, rather than the inferior glenohumeral ligament as in traumatic anterior shoulder dislocations. These findings would be useful for defining treatment strategies for internal impingement with anterior instability in overhead throwing athletes.

Anterior glenohumeral capsular ligament reconstruction with hamstring autograft for internal impingement with anterior instability of the shoulder in baseball players: preliminary surgical outcomes.

BACKGROUND: Shoulder pain and dysfunction are common in baseball players, and although "internal impingement" is recognized as one of the most common pathologies of shoulder dysfunction, the optimal surgical treatment for internal impingement with anterior instability of the shoulder remains controversial. This study evaluated baseball players' preliminary outcomes following anterior glenohumeral capsular ligament reconstruction for internal impingement with anterior instability of the shoulder. METHODS: Twelve baseball players (all male; mean age, 20.5 ± 2.2 years) with internal impingement and anterior instability managed via anterior glenohumeral capsular ligament reconstruction were examined. The mean follow-up period was 25.3 ± 4.6 months. Anterior glenohumeral capsular ligament reconstruction was performed with a knee hamstring autograft for balanced stability and laxity with two major targets: to prevent hyperangulation and translation in horizontal abduction and to mimic the individual arm cocking position at the final decision of tension. Preoperative and final follow-up evaluations were performed using Jobe's postoperative grading system; the Kerlan-Jobe Orthopaedic Clinic Overhead Athletes Shoulder and Elbow Score; Disabilities of the Arm, Shoulder and Hand sports module; plain radiographs; and magnetic resonance imaging. RESULTS: Jobe's postoperative grading system score, the Kerlan-Jobe Orthopaedic Clinic Overhead Athletes Shoulder and Elbow Score, and the Disabilities of the Arm, Shoulder and Hand sports module score improved significantly from 20.4 ± 12.2, 28.4 ± 8.3, and 80.2 ± 11.1 points preoperatively to 88.8 ± 13.6, 80.8 ± 7.7, and 22.4 ± 18.7 points postoperatively, respectively (P < .001, .0025, <0.001, respectively). Both clinical and imaging evaluations revealed improved internal impingement with anterior instability after anterior glenohumeral capsular ligament reconstruction. The mean external rotation at abduction significantly decreased from 113° preoperatively to 104° postoperatively. At follow-up, 10 of the 12 athletes (83.3%) returned to their prior competitive level. Plain radiographs and magnetic resonance imaging revealed no obvious loosening of the graft or screws. CONCLUSIONS: Anterior glenohumeral capsular ligament reconstruction resulted in preferable clinical outcomes for young baseball players who experienced pain during the throwing motion. Stabilization of the glenohumeral joint with autografting of the knee hamstring may thus represent a solution for internal impingement with anterior instability in overhead throwing athletes.

Three-Dimensional Quantitative Evaluation of the Scapular Skin Marker Movements in the Upright Posture.

Motion capture systems using skin markers are widely used to evaluate scapular kinematics. However, soft-tissue artifact (STA) is a major limitation, and there is insufficient knowledge of the marker movements from the original locations. This study explores a scapular STA, including marker movements with shoulder elevation using upright computed tomography (CT). Ten healthy males (twenty shoulders in total) had markers attached to scapular bony landmarks and underwent upright CT in the reference and elevated positions. Marker movements were calculated and compared between markers. The bone-based and marker-based scapulothoracic rotation angles were also compared in both positions. The median marker movement distances were 30.4 mm for the acromial angle, 53.1 mm for the root of the scapular spine, and 70.0 mm for the inferior angle. Marker movements were significantly smaller on the superolateral aspect of the scapula, and superior movement was largest in the directional movement. Scapulothoracic rotation angles were significantly smaller in the marker-based rotation angles than in the bone-based rotation angles of the elevated position. We noted that the markers especially did not track the inferior movement of the scapular motion with shoulder elevation, resulting in an underestimation of the marker-based rotation angles.

Lumbar spinal surgery improves locomotive syndrome in elderly patients with lumbar spinal canal stenosis: A multicenter prospective study.

BACKGROUND: Owing to musculoskeletal dysfunction, locomotive syndrome elevates the risk of requiring nursing care. Among degenerative musculoskeletal disorders, lumbar spinal canal stenosis (LSS) associates with locomotive syndrome; however, whether lumbar spinal surgery for LSS improves locomotive syndrome remains unclear. Hence, this study aimed to identify the efficacy of lumbar spinal surgery on locomotive syndrome among elderly patients with LSS. METHODS: We prospectively collected the clinical data from multiple institutions of patients (age >65 years) who underwent lumbar spinal surgery. Patients were examined for the locomotive syndrome risk test, including the stand-up Test, the two-step Test, and the 25-question risk assessment, 1-day preoperatively and 6-month and 1-year postoperatively. Using a logistic regression model, we identified factors associated with improvement of locomotive syndrome in the total assessment. RESULTS: Overall, we examined the data of 166 patients in this study. Upon converting each score of three tests to the stage of locomotive syndrome, the two-step test and the 25-question risk assessment revealed marked improvement in the postoperative distribution of stages. However, the stand-up test revealed a comparable distribution of stages pre- and postoperatively. In the total assessment, the postoperative distribution of stages was significantly improved than that preoperatively. The multivariable analysis revealed that failed back surgery syndrome [odds ratio (OR), 0.2; 95% confidence interval (CI): 0.04-1.05; P = 0.057)] and preoperative stage of 2 in stand-up test (OR, 0.2; 95% CI: 0.05-1.02; P = 0.054) tended to have inverse association with postoperative improvement of locomotive syndrome in the total assessment. CONCLUSIONS: Lumbar spinal surgery improved the stage of locomotive syndrome among elderly patients with LSS. This study suggests that lumbar spinal surgery for LSS could be beneficial in alleviating locomotive syndrome.

A designed cell-penetrating human SOCS2 protein suppresses GH-dependent cancer cell proliferation.

Suppressor of cytokine signaling (SOCS) 2, a negative regulator of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), which is associated with acromegaly and cancers, is a promising candidate molecule for treating various diseases. To facilitate its use in protein therapy, we designed and constructed a human SOCS2 protein containing a membrane-permeable peptide sequence and expressed it in an Escherichia coli system. The partially purified recombinant protein was effectively delivered into several cancer cell lines and inhibited cell growth. Biochemical analysis showed that the recombinant SOCS2 protein interacted with growth hormone receptor (GHR) and downregulated GH-STAT5 signaling target genes. Our results suggest that the designed cell-penetrating SOCS2 protein will be useful in intercellular protein therapy to cure cancers. Abbreviations: SOCS: suppressor of cytokine signaling; GH: growth hormone; GHR: growth hormone receptor; IGF-1: insulin-like growth factor 1; CP: cell-penetrating; STAT: signal transducer and activator of transcription; JAK: Janus kinase; HNF: hepatocyte nuclear factor; MTM: membrane-translocating motif; HIV: human immunodeficiency virus.

Lumbar spinal canal stenosis leads to locomotive syndrome in elderly patients.

BACKGROUND: Locomotive syndrome is a condition in which the ability to lead a normal life is restricted owing to a dysfunction in one or more of the parts of the musculoskeletal system. Although lumbar spinal canal stenosis (LSS) is considered to cause locomotive syndrome, a detailed assessment of the association between two pathologies has not yet been reported. METHODS: The clinical data of patients aged > 65 years old who planned to undergo surgery for LSS at multiple institutions were prospectively collected from April 2016 to August 2017. A total of 200 participants comprising 120 men and 80 women were enrolled in this study. Association of severity of LSS evaluated by Zurich Claudication Questionnaire scores with three locomotive syndrome risk tests (Stand-up Test, the Two-step Test, and a 25-question risk assessment) and Timed Up-and-Go Test were evaluated. RESULTS: In the total assessment of locomotive syndrome, 96.5% of the participants were diagnosed as grade 2, and the remaining 3.5% were diagnosed as grade 1. When the participants were divided into 3 groups according to the LSS severity, the scores of all locomotive syndrome risk tests were significantly worse with increasing LSS severity. Logistic regression analysis revealed that LSS severity was positively correlated with the risk level of locomotive syndrome evaluated by the Two-step Test (OR = 3.45, CI = 1.33-8.96). CONCLUSIONS: All LSS patients with surgical indications were diagnosed as having locomotive syndrome. In addition, our results indicated that LSS severity is potentially associated with the progression of locomotive syndrome. The treatment of LSS may be beneficial in alleviating the risk for locomotive syndrome.

Stride length of elderly patients with lumbar spinal stenosis: Multi-center study using the Two-Step test.

BACKGROUND: Short stride length is one of clinical symptoms associated with lumbar spinal stenosis (LSS). Short stride is a risk factor for falls; therefore, identification of factors associated with short stride is critical for fall prevention in LSS patients. Although the Two-Step test can conveniently assess maximal stride length, it has not become widely used; therefore, its data are limited. We identified the potential factors associated with short stride of elderly LSS patients using Two-Step test. METHODS: Clinical data of patients aged >65 years who planned to undergo surgery for LSS were prospectively collected at multiple institutions. Patients were assessed with the Two-Step test and Timed Up-and-Go Test prior to surgery; 357 consecutive patients were enrolled. We determined the cut-off value of the Two-Step test score for short stride, referring to the Timed Up-and-Go Test score of 13.5 s, used to indicate high risk of falls in elderly individuals. Logistic regression model was constructed to identify factors associated with short stride. RESULTS: The Two-Step test score showed moderate-to-strong inverse correlation with that of Timed Up-and-Go Test (r = -0.65, p < 0.001). Using the tentative Two-Step test cut-off value (0.93) for short stride, multivariable analysis showed that age ≥80 years (OR = 2.3, 95% CI:1.1-4.8), a score of <60 for lumbar function in Japanese Orthopedic Association Back Pain Evaluation Questionnaire (OR = 2.7, 95% CI:1.5-4.7), motor deficit (OR = 2.7, 95% CI:1.2-6.1), and sagittal vertical axis ≥50 mm (OR = 2.1, 95% CI:1.2-3.5) were factors significantly associated with short stride in elderly patients with LSS. CONCLUSIONS: Using the Two-Step test, we found that 80 years old and over, lumbar dysfunction, motor deficit of the lower extremities, and forward-bent posture were associated with short stride in LSS patients. Therefore, elderly LSS patients with these conditions may have a higher risk for falls.

Variation in stress distribution patterns across the radial head fovea in osteochondritis dissecans: predictive factors in radiographic findings.

BACKGROUND: Predictive factors for the development of osteoarthritis in adolescent osteochondritis dissecans (OCD) of the humeral capitellum remain unclear. The objectives of this study were to assess subchondral bone density in the radial head fovea of patients with OCD and to evaluate stress distribution in the radiocapitellar joint. The relationship between radiologic classification and stress distribution, according to multivariate ordinal regression analysis, was also investigated. METHODS: Computed tomography (CT) imaging data from 54 male patients with OCD (mean age, 13.1 years) were collected. Stress in the radial head fovea was measured using CT osteoabsorptiometry. A stress map was constructed and divided into 4 sections, and percentages of high-density regions in each section were quantitatively analyzed. Multivariate ordinal regression analyses were performed of bone density, incorporating the stage, location, and size of the OCD lesion and the presence of medial elbow disturbance in the radiographic images. RESULTS: The percentage of high-density area in the anteromedial, posteromedial, and the anterolateral sections of the radial head fovea were significantly increased compared with the posterolateral section. Multivariate ordinal regression analysis revealed that the location and size of the lesion and a history of excessive valgus stress were associated with imbalances in the radial head fovea. CONCLUSIONS: When the OCD lesion is large and located laterally and a medial epicondyle disturbance is apparent on radiographs, the risk for developing advanced radiocapitellar osteoarthritis should be considered. These findings can be useful in the decision-making process for treating OCD.

TIPE2 (Tumor Necrosis Factor α-induced Protein 8-like 2) Is a Novel Negative Regulator of TAK1 Signal.

TIPE2 (TNF-α-induced protein 8-like 2) is a novel death effector domain protein and is a negative regulator of the innate and adaptive immune response. Although it has been demonstrated that caspase-8 contributes to the negative regulation of TIPE2, the negative regulatory mechanism is not entirely understood. Here, we demonstrate that TIPE2 interacts with TGF-ß-activated kinase 1 (TAK1), a crucial regulatory molecule of inflammatory and immune signals, and consequently acts as a powerful negative regulator of TAK1. The interaction between endogenous TIPE2 and TAK1 was observed in RAW264.7 macrophage-like cells and mouse primary cells derived from spleen and thymus. The TIPE2 amino acid 101-140 region interacted with TAK1 by binding to the amino acid 200-291 region of the internal kinase domain of TAK1. TIPE2 interfered with the formation of the TAK1-TAB1-TAB2 complex and subsequently inhibited activation of TAK1 and its downstream molecules. Importantly, silencing TIPE2 through RNA interference attenuated the inhibitory action of TIPE2 on LPS- and TNF-α-stimulated TAK1 activity. Exogenous TIPE2 101-140, the region that interacts with TAK1, also inhibited LPS- and TNF-α-stimulated NF-κB reporter activity. Interestingly, cell-permeable TIPE2 protein maintained its binding ability with TAK1 and exhibited the same inhibitory action of native TIPE2 on TLR4 signaling in vitro Thus, cell-permeable TIPE2 protein is a potential candidate for intracellular protein therapy for TAK1-related diseases. The present study demonstrates that TIPE2 acts as a novel negative regulator of inflammatory and immune responses through TAK1 signaling.

Thoracic outlet syndrome in overhead athletes.

Background: We aimed to retrospectively compare the clinical outcomes of endoscopy-assisted first-rib resection for thoracic outlet syndrome (TOS) between overhead athletes and nonathletes and investigate the return to same-level sports rate in overhead athletes. Methods: We retrospectively reviewed 181 cases with TOS (75 women, 106 men; mean age, 28.4 years; range, 12-57 years) who underwent endoscopy-assisted first-rib resection. We divided into two groups: 79 overhead athletes and 102 nonathletes groups. A transaxillary approach for first-rib resection and neurovascular decompression was performed under magnified visualization. Endoscopic findings related to the neurovascular bundle, interscalene distance, and scalene muscle were evaluated intraoperatively. We assessed the Roos and Disability of the Arm, Shoulder, and Hand scores, return to same-level sports rate, and ball velocity. Results: Overhead athletes were significantly more likely to be men, younger, used the dominant side more frequently, and have a larger physique, more shoulder and elbow pain, and shorter symptom duration. The outcomes of the Roos score revealed significant differences in excellent or good results between overhead athletes (91.1%) and nonathletes (62.8%). The two groups significantly differed in preoperative and postoperative Disability of the Arm, Shoulder, and Hand and recovery rate scores (P = .007, < .001, < .001). Conclusion: Overhead athletes with TOS were more likely to be men, younger, dominant side more frequently, and have more shoulder and elbow pain, and a shorter symptom duration. Endoscopy-assisted transaxillary first-rib resection and neurolysis provided superior clinical outcomes in overhead athletes with TOS compared with nonathletes and a high return-to-same-level-play rate in sports.

Arthroscopic superior capsule reconstruction augmentation using a semitendinosus autograft in massive reparable rotator cuff tears.

Background: Arthroscopic superior capsule reconstruction (SCR) augmentation is a viable treatment option for massive reparable cuff tears. This study aimed to retrospectively compare clinical and imaging outcomes of patients with reparable massive rotator cuff tears after arthroscopic rotator cuff repair (ARCR) with those after SCR augmentation using a semitendinosus autograft. Methods: We retrospectively compared 50 patients with massive reparable rotator cuff tears who underwent ARCR and SCR augmentation (n = 25 each). Patients were clinically followed up for at least 2 years, and the American Shoulder and Elbow index, other patient-reported outcomes, active range of motion, and radiography and magnetic resonance imaging findings were assessed. Results: At the final follow-up, both patient groups showed significant improvements in forward elevation in range of motion and visual analog scale scores. Improvements in the American Shoulder and Elbow scores in the SCR augmentation group were significantly superior to those in the ARCR group (48.3 and 28.9, P < .01). There was a significant difference in the retear rate between the SCR augmentation group and ARCR group (20% and 56%, respectively; P = .009). Conclusion: Our study demonstrated that patient-reported outcomes and retear rates in patients who underwent SCR augmentation with rotator cuff repair for massive rotator cuff tears significantly improved compared with those in patients who underwent ARCR without augmentation. Augmentation with semitendinosus autografting during rotator cuff repair represents a solution for patients with massive reparable rotator cuff tears.

Dynamic evaluation of the sternoclavicular and acromioclavicular joints using an upright four-dimensional computed tomography.

In the analysis of the shoulder complex, the sequential changes occurring in the sternoclavicular and acromioclavicular joints during active shoulder motion are challenging to track. This study aimed to investigate the in vivo sternoclavicular and acromioclavicular joint motions during active elevation, including the sequential changes in these joint spaces using upright four-dimensional computed tomography (4DCT). Bilateral shoulders of 12 healthy volunteers upright 4DCT were obtained during active elevation similar to a "hands up" motion. The sternoclavicular and acromioclavicular rotation angles, joint distances, and closest points on the clavicle relative to the thorax and scapula were evaluated during 10°-140° of humerothoracic elevation. During humerothoracic elevation, the clavicle elevated, retracted, and rotated posteriorly relative to the thorax, whereas the scapula rotated upwardly, internally, and posteriorly relative to the clavicle. All the sternoclavicular and acromioclavicular joint rotation angles were significantly different at ≥ 30°-50° of humerothoracic elevation compared with 10° of humerothoracic elevation. The mean sternoclavicular and acromioclavicular joint distances were 2.2 ± 1.1 mm and 1.6 ± 0.9 mm, respectively. The closest points were located on the anteroinferior part of the medial and lateral clavicle in the sternoclavicular and acromioclavicular joints, respectively. Significant differences were observed in the acromioclavicular joint distance and anterior/posterior movements of the closest points in the sternoclavicular and acromioclavicular joints compared with 10° of humerothoracic elevation. Our sternoclavicular and acromioclavicular closest point results indicate that the impingement tends to occur at the anteroinferior part of the medial and lateral aspects of the clavicle and may be related to osteoarthritis.

Drug-dependent analgesic efficacy in interscalene block for postoperative pain after arthroscopic rotator cuff repair: a comparison between ropivacaine and levobupivacaine.

Background: Interscalene brachial plexus block (ISB) for arthroscopic rotator cuff repair (ARCR) provides high analgesic efficacy for postoperative pain. However, different drug efficacies remain unclear. This retrospective study compared the efficacy of ropivacaine and levobupivacaine in a single-dose ISB for pain control after ARCR. Methods: This study included 173 patients who underwent ARCR; they were divided into the ISBR group (n = 61) that received ISB with 20 mL 0.375% ropivacaine and 3.3 mg dexamethasone, and the ISBL group (n = 112) that received ISB with 20 mL 0.25% levobupivacaine and 3.3 mg dexamethasone. Visual analog scale (VAS) pain scores were evaluated at 1, 4, 8, 12, 24, and 48 hours, postoperatively. Rebound pain was defined as a difference of ≥ 5 points between the highest and lowest VAS pain scores. Results: The mean VAS pain scores at 1 hour were not significantly different between the groups. ISBL administration resulted in significantly lower VAS pain scores at 4, 8, 12, and 24 hours than ISBR administration. Rebound pain rates in the ISBR and ISBL groups were 41.0% and 17.9%, respectively. Rebound pain was more frequent in the ISBR than in the ISBL group. Conclusion: ISB with levobupivacaine and dexamethasone can provide more effective postoperative pain control after ARCR than ropivacaine and dexamethasone.

Three-dimensional shoulder kinematics: Upright four-dimensional computed tomography in comparison with an optical three-dimensional motion capture system.

Although shoulder kinematics have been analyzed by various methods, dynamic shoulder motion is difficult to track. This study aimed to validate the shoulder kinematic analysis using upright four-dimensional computed tomography (4DCT) and to compare the results with optical three-dimensional motion capture. During active elevation, bilateral shoulders of 10 healthy volunteers were tracked using 4DCT and motion capture. The scapulothoracic and glenohumeral rotations and the scapulohumeral rhythm (SHR) at each position were calculated, and the differences between 4DCT and motion capture were compared. During 10-140° of humerothoracic elevation, the scapulothoracic joint showed upward rotation, internal rotation, and posterior tilting, and the glenohumeral joint showed elevation, external rotation, and anterior plane of elevation in both analyses. In scapulothoracic rotations, the mean differences between the two analyses were -2.6° in upward rotation, 13.9° in internal rotation, and 6.4° in posterior tilting, and became significant with humerothoracic elevation ≥110° in upward rotation, ≥50° in internal rotation, and ≥100° in posterior tilting. In glenohumeral rotations, the mean differences were 3.7° in elevation, 9.1° in internal rotation, and -8.8° in anterior plane of elevation, and became significant with humerothoracic elevation ≥110° in elevation, ≥90° in internal rotation, and ≥100° in anterior plane of elevation. The mean overall SHRs were 1.8 in 4DCT and 2.4 in motion capture, and the differences became significant with humerothoracic elevation ≥100°. The 4DCT analysis of in vivo shoulder kinematics using upright computed tomography scanner is feasible, but the values were different from those by skin-based analysis at the elevated arm positions.

Evaluation of hypervascularity in synovitis of the shoulder using ultrasound: comparison of preoperative ultrasound findings and intraoperative arthroscopic findings.

Background: Synovitis of the shoulder causes pain; however, it is difficult to accurately determine the area and degree of synovitis from preoperative images. This study investigated the correlation between intraoperative arthroscopic findings and preoperative power Doppler ultrasonography (PDUS) findings for synovitis evaluation. Methods: Forty patients (mean age = 62.0 years; 24 men and 16 women) underwent arthroscopic surgery for partial rotator cuff tears. Three observation areas were evaluated: rotator interval (RI), subacromial bursa, and bicipital groove. The Doppler flow areas and PDUS grade were measured one day before surgery. Arthroscopic findings were visualized intraoperatively and classified into 3 groups: pale, pink, and red. The correlation between the arthroscopic classification and PDUS findings was analyzed. Results: The correlation between intraoperative arthroscopic classification and preoperative PDUS findings, Doppler flow area and PDUS grade, was high for the RI (r = 0.82, 0.70). There was no correlation for the subacromial bursa (r = 0.01, -0.02) and the bicipital groove (r = -0.03, 0.3). Conclusion: Hypervascularity findings in the PDUS were highly correlated with arthroscopic color classification in the RI. Therefore, visualization of hypervascularity in the RI area could be a reliable measure for the assessment of glenohumeral synovitis in patients with partial-thickness rotator cuff tear.

Development and validation of machine learning-based predictive model for clinical outcome of decompression surgery for lumbar spinal canal stenosis.

BACKGROUND CONTEXT: Although the results of decompression surgery for lumbar spinal canal stenosis (LSS) are favorable, it is still difficult to predict the postoperative health-related quality of life of patients before surgery. PURPOSE: The purpose of this study was to develop and validate a machine learning model to predict the postoperative outcome of decompression surgery for patients with LSS. STUDY DESIGN/SETTING: A multicentered retrospective study. PATIENT SAMPLE: A total of 848 patients who underwent decompression surgery for LSS at an academic hospital, tertiary center, and private hospital were included (age 71±9 years, 68% male, 91% LSS, level treated 1.8±0.8, operation time 69±37 minutes, blood loss 48±113 mL, and length of hospital stay 12±5 days). OUTCOME MEASURES: Baseline and 2 years postoperative health-related quality of life. METHODS: The subjects were randomly assigned in a 7:3 ratio to a model building cohort and a testing cohort to test the models' accuracy. Twelve predictive algorithms using 68 preoperative factors were used to predict each domain of the Japanese Orthopedic Association Back Pain Evaluation Questionnaire and visual analog scale scores at 2 years postoperatively. The final predictive values were generated using an ensemble of the top five algorithms in prediction accuracy. RESULTS: The correlation coefficients of the top algorithms for each domain established using the preoperative factors were excellent (correlation coefficient: 0.95-0.97 [relative error: 0.06-0.14]). The performance evaluation of each Japanese Orthopedic Association Back Pain Evaluation Questionnaire domain and visual analog scale score by the ensemble of the top five algorithms in the testing cohort was favorable (mean absolute error [MAE] 8.9-17.4, median difference [MD] 8.1-15.6/100 points), with the highest accuracy for mental status (MAE 8.9, MD 8.1) and the lowest for buttock and leg numbness (MAE 1.7, MD 1.6/10 points). A strong linear correlation was observed between the predicted and measured values (linear correlation 0.82-0.89), while 4% to 6% of the subjects had predicted values of greater than±3 standard deviations of the MAE. CONCLUSIONS: We successfully developed a machine learning model to predict the postoperative outcomes of decompression surgery for patients with LSS using patient data from three different institutions in three different settings. Thorough analyses for the subjects with deviations from the actual measured values may further improve the predictive probability of this model.

Endoscopic-Assisted Transaxillary Approach for First Rib Resection in Thoracic Outlet Syndrome.

PURPOSE: To assess the feasibility, safety, and clinical outcomes of an endoscopic-assisted transaxillary approach of first rib resection for thoracic outlet syndrome (TOS) and to compare the differences in demographic and clinical data between satisfactory and unsatisfactory outcomes using this approach. METHODS: We retrospectively identified patients who underwent endoscopic-assisted first rib partial resection. A transaxillary approach for the first rib resection and neurovascular decompression were undertaken under magnified visualization. Endoscopic classification of neurovascular bundle (NVB) patterns and interscalene distance (ISD) between anterior and middle scalene muscles were evaluated intraoperatively. We assessed the Roos and DASH scores. RESULTS: We reviewed 131 cases of TOS (48 women and 83 men; mean age 26.2 years; range 12 to 57). Roos classification revealed 80.2% excellent or good results. DASH scores improved significantly from 40.7 ± 20.0 to 15.7 ± 19.6 (P < .001). The complication rate was low (5.3%), with 4 pneumothorax and 3 other complications. Intraoperative NVB classification revealed 30 cases of parallel type, in which the artery and nerve travel in parallel; 69 oblique types, and 30 vertical types, in which the nerve was completely behind the middle scalene muscle or abnormal band. The ISD was narrower (5.4 ± 3.6 mm) than in previous cadaveric studies. The ISD in the parallel patterns was wider than that in the vertical patterns. In the satisfactory group, we found a significantly larger number of men, younger patients, athletes, and patients with a lower preoperative DASH score. CONCLUSIONS: An endoscopic-assisted transaxillary approach for first rib resection in TOS provides an excellent magnified visualization, safely allowing sufficient decompression of the neurovascular bundle and satisfactory surgical outcomes. Younger male athletes with TOS may be better candidates for this procedure. LEVEL OF EVIDENCE: IV, therapeutic case series.

Predictors of Unsuccessful Nonoperative Management of Capitellar Osteochondritis Dissecans.

BACKGROUND: Osteochondritis dissecans of the humeral capitellum (capitellar OCD) is a common injury among adolescent throwing athletes. Some younger patients with incomplete maturity of the epiphysis and early-stage capitellar OCD are good candidates for nonoperative treatment. However, during initial examination, predicting the need for surgical treatment in patients with capitellar OCD is difficult. PURPOSE: To perform multivariate ordered logistic regression analysis of data obtained from patients' medical records and images on initial examination and identify the predictors of unsuccessful nonoperative management of capitellar OCD. STUDY DESIGN: Cohort study (prognosis); Level of evidence, 2. METHODS: This study included 245 elbows with capitellar OCD (all male; mean age, 14 years [range, 10-27 years]). Patients were divided into 3 groups comprising 148 elbows requiring an immediate operation on initial examination, 48 requiring nonsurgical treatment, and 49 requiring an operation after nonoperative management. Baseline data and radiographic parameters, such as lesion location, lesion size, modified Minami classification, radial head size, skeletal age difference between both elbows on initial examination, lesion size on computed tomography, and staging on magnetic resonance imaging, were retrospectively reviewed. Univariate and multivariate ordered logistic regression analyses of spontaneous healing of the lesion were conducted. RESULTS: Univariate logistic regression analysis showed that radial head enlargement and skeletal age difference were significantly associated with spontaneous healing. In multivariate ordered logistic regression analysis, radial head enlargement (anteroposterior and lateral) and skeletal age difference were significant predictors of lack of spontaneous healing (odds ratio [OR], 2.76, P =.025; OR, 7.92, P =.026; and OR, 1.84, P =.0089, respectively). CONCLUSION: To predict spontaneous healing in the moderate stage, plain radiographs would be important to evaluate radiocapitellar congruity and skeletal age. This study showed that preoperative radiographic findings of radial head enlargement and advanced skeletal age of the throwing side compared with that of the nonthrowing side were predictors of advanced-stage capitellar OCD. Despite several limitations, the statistical significance and correlations herein provide important information on preoperative surgical planning to surgeons.