Evaluation of Radiographic Changes 5 Years After Arthroscopic Rotator Cuff Repair

Background:

Radiographic changes in the glenohumeral joint often occur after rotator cuff repair; however, the details of the progression and underlying causes remain unknown.

Purpose:

To retrospectively evaluate the timing and frequency of radiographic changes after arthroscopic rotator cuff repair and to clarify the predictive factors that affect the onset of such changes using multivariate analysis.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

We retrospectively reviewed 100 patients with 5 years of follow-up after arthroscopic rotator cuff repair and evaluated the postoperative shift in radiographic findings on plain radiographs every year during follow-up. Factors related to osteoarthritis, acromial spur re-formation, and greater tuberosity resorption at 5 years after surgery were evaluated using logistic regression analyses. Explanatory variables included preoperative factors, intraoperative factors, and postoperative retear. Baseline variables significant in the univariate analyses were included in the multivariate models.

Results:

Of the 100 patients, 12 developed osteoarthritis, 26 developed acromial spur formation, and 16 developed greater tuberosity resorption at 5 years after surgery. The incidence and grade of osteoarthritis and acromial spur gradually increased over time postoperatively. On the other hand, greater tuberosity resorption developed within 2 years after surgery but did not progress later. Multivariate analysis showed that a larger anteroposterior tear size (odds ratio [OR], 1.09; 95% CI, 1.01-1.17; P = .037) was a risk factor for postoperative osteoarthritis. Early retear (OR, 10.26; 95% CI, 1.03-102.40; P = .047) was a risk factor for acromial spur re-formation. Roughness of the greater tuberosity (OR, 9.07; 95% CI, 1.13-72.82; P = .038) and larger number of suture anchors (OR, 3.34; 95% CI, 1.66-6.74; P = .001) were risk factors for greater tuberosity resorption.

Conclusion:

Our study showed that radiographic changes occurred in 40% of patients within 5 years after arthroscopic rotator cuff repair. While the osteoarthritic changes and acromial spur re-formation gradually progressed postoperatively, the greater tuberosity resorption stopped within 2 years after surgery. Tear size, morphology of the greater tuberosity, and the number of suture anchors can affect radiographic changes. Furthermore, this study suggested that acromial spur re-formation may be an indicator of early retears.

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.

Risk factors of radiographic severity of massive rotator cuff tear

As massive rotator cuff tears progress, various radiographic changes occur; however, the factors associated with radiographic changes remain largely unknown. This study aimed to determine the factors that affect radiographic severity in massive rotator cuff tears using multivariate analyses. We retrospectively reviewed 210 shoulders with chronic massive rotator cuff tears. The dependent variables were superior migration of the humeral head (Hamada grades 2-3), narrowing of the glenohumeral joint (grade 4), and humeral head collapse (grade 5). Baseline variables that were significant in univariate analyses were included in multivariate models. There were 91, 59, 43, and 17 shoulders classified as Hamada grades 1, 2-3, 4, and 5, respectively. Multivariate analysis showed that infraspinatus tear (P = 0.015) and long head of biceps (LHB) tendon rupture (P = 0.007) were associated with superior migration of humeral head. Superior subscapularis tear (P = 0.003) and LHB tendon rupture (P < 0.001) were associated with narrowing of glenohumeral joint. Female sex (P = 0.006) and superior subscapularis tear (P = 0.006) were associated with humeral head collapse. This study identified the rupture of infraspinatus and LHB as risk factors of superior migration of humeral head, and the rupture of subscapularis and LHB and female sex as risk factors of cuff tear arthropathy.

A Rare Intra-articular Abnormality in the Posterior Radiocapitellar Joint: A Case Report

Introduction

Posterior radiocapitellar synovial plica excision is sometimes performed for lateral epicondylitis after debridement of the extensor carpi radialis brevis (ECRB) tendon. We describe a rare intra-articular abnormality of the posterior radiocapitellar joint diagnosed on posterior arthroscopic observation.

Case Report

A 48-year-old man presented with posterolateral pain and discomfort in his left elbow. A diagnosis of lateral epicondylitis was made, and arthroscopic debridement of the ECRB tendon was performed. Posterior arthroscopic examination revealed a tendon-like abnormality running longitudinally along the articular surface of the capitulum of the humerus. The abnormality was resected using a shaver, and symptoms improved postoperatively.

Conclusion

In patients with posterolateral pain and discomfort or catching of the elbow, posterior arthroscopic confirmation of the intra-articular structure is recommended after debridement of the ECRB tendon.

Fracture-Separation of the Medial Humeral Epicondyle Caused by Arm Wrestling: A Systematic Review

Background:

Arm wrestling is a popular sport in which various injuries have occurred, even in children.

Purpose:

To analyze reported fracture-separation of the medial humeral epicondyle (MHE) caused by arm wrestling to determine its mechanism and provide a current overview.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

The PubMed and Web of Science databases were searched using the terms “arm wrestling” and “humeral fracture” or “medial humeral epicondyle fracture”; and “sports” and “humeral fracture” or “medial humeral epicondyle fracture,” following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The inclusion criteria were English full-text articles on arm wrestling–induced MHE fracture that described patient characteristics and presented appropriate images. Studies with a lack of appropriate images or detailed description of the injury situation were excluded. The patient characteristics were evaluated, and the ratios of treatment selection and outcomes were evaluated using the chi-square test.

Results:

Included were 27 studies with a total of 68 patients, all boys with a mean age of 14.6 ± 1.24 years (based on n = 65, with 3 patients excluded from this calculation as no definitive age was provided). Boys aged 14 to 15 years accounted for 72% (49/68) of the cases. Fracture occurred suddenly during arm wrestling in 63 boys, while the other 5 boys experienced antecedent medial elbow pain. The match status at the time of injury, provided for 46 patients, was varied. In 31 boys with known match details, injury occurred when a participant suddenly added more force to change the match status. Eight patients displayed anterior and/or proximal displacement of the MHE fragment. Treatment was nonoperative in 25 patients and operative in 38 patients (n = 63, excluding 5 unknown patients). In 35 patients followed up for ≥3 months (mean, 17.6 ± 12.3 months), outcomes were not significantly different between the operative and nonoperative groups.

Conclusion:

MHE fracture-separation caused by arm wrestling occurred mostly in boys aged 14 to 15 years regardless of the match status. The likely direct cause is forceful traction of the attached flexor-pronator muscles. A relative mechanical imbalance during adolescence may be an underlying cause. A sudden change from concentric to eccentric contraction of the flexor-pronator muscles increases the likelihood of fracture occurrence.

Three-dimensional alignment of the upper extremity in the standing neutral position in healthy subjects

Background

Though alignment of the spine and lower extremities in the standing neutral position has been evaluated, a few studies evaluating the alignment of the upper extremities have also been made. This study assessed the normal alignment of the upper extremities in the standing neutral position and clarified the three-dimensional angular rotations of the upper extremity joints.

Methods

Computed tomography (CT) images of 158 upper extremities from 79 healthy volunteers were prospectively acquired in the standing neutral position using an upright CT scanner. Three-dimensional coordinate systems of the thorax, scapula, humerus, and forearm were designated, and three-dimensional angular rotations of the scapulothoracic, glenohumeral, and elbow joints were calculated.

Results

The median angle of the scapulothoracic joint was 9.2° (interquartile range [IQR], 5.2°–12.5°) of upward rotation, 29.0° (IQR, 24.9°–33.3°) of internal rotation, and 7.9° (IQR, 4.3°–11.8°) of anterior tilt. The median angle of the glenohumeral joint was 4.5° (IQR, 0.9°–7.8°) of abduction, 9.0° (IQR, 2.2°–19.0°) of internal rotation, and 0.3° (IQR, − 2.6°–3.1°) of extension. The median angle of the elbow joint was 9.8° (IQR, 6.9°–12.4°) of valgus, 90.2° (IQR, 79.6°–99.4°) of pronation, and 15.5° (IQR, 13.2°–18.1°) of flexion. Correlations in angular rotation values were found between the right and left upper extremities and between joints.

Conclusions

This study clarified the three-dimensional angular rotation of upper extremity joints in the standing neutral position using an upright CT scanner. Our results may provide important insights for the functional evaluation of upper extremity alignment.

Arthroscopic Distal Clavicle Resection for an Acromioclavicular Ganglion Cyst with Cuff Tear Arthropathy: A Case Report

CASE

A 77-year-old man with an acromioclavicular joint ganglion cyst with cuff tear arthropathy had a large mass in the left shoulder. Arthroscopic distal clavicle resection successfully relieved his symptoms without loss of shoulder function by enlargement of the bypass between the cyst and subacromial space through the acromioclavicular joint.

CONCLUSION

Arthroscopic distal clavicle resection can remove a 1-way check valve in a minimally invasive manner. This case indicated that arthroscopic distal clavicle resection could be a useful treatment option for patients with acromioclavicular joint ganglion cysts with functional but irreparable rotator cuff tears.

Bone Block Grafting for Posterior Instability After Anatomical Total Shoulder Arthroplasty: A Case Report

CASE

A 60-year-old woman with avascular necrosis of the right humeral head underwent anatomical total shoulder arthroplasty (TSA); however, recurrent posterior dislocation occurred 13 months postoperatively. We performed bone block grafting of an autologous iliac crest to the posterior glenoid and posterior capsular plication, after which satisfactory postoperative shoulder function without residual joint instability was achieved.

CONCLUSION

The presented case had recurrent posterior dislocation after TSA without any abnormal findings in the prosthetic components. Posterior bone block grafting with capsular plication should be considered a viable option for posterior instability after anatomical TSA.

Aging Aggravates the Progression of Muscle Degeneration After Rotator Cuff Tears in Mice

PURPOSE

The purpose of this study was to evaluate the impact of aging on muscle degeneration after rotator cuff tear (RCT) in mice.

METHODS

Young (12-week-old) and aged (50-to-60-week-old) female C57BL/6 mice were used (n = 29 for each group). The rotator cuff was transected, and the proximal humerus was removed to induce degeneration of the rotator cuff muscles. The mice were euthanized 4 and 12 weeks after the procedure (referred to as RCT-4wk mice and RCT-12wk mice, respectively) and compared with the sham-treated mice. The supraspinatus muscles were collected for histology, Western blot analysis, and gene expression analyses.

RESULTS

There was a significant increase in fat tissue in aged RCT-4wk mice (P = .001) and aged RCT-12wk mice (P < .001) compared with sham-treated aged mice, and aged RCT-12wk mice had a significantly increased fat area ratio compared with aged RCT-4wk mice (P < .001). The fat area was significantly larger in both the aged RCT-4wk (P = .002) and RCT-12wk mice (P < .001) than in the corresponding young mice. Muscular fibrosis was significantly increased in aged RCT-12wk mice compared with aged sham-treated mice (P = .005) and young RCT-12wk mice (P = .016). There were also significant increases in the expression of perilipin and transcripts of adipogenic and fibrogenic differentiation markers in aged RCT mice compared with young RCT mice.

CONCLUSION

The present results show that aging is critically involved in the pathology of muscular fatty infiltration and fibrosis after RCT, and muscular degeneration progresses over time in aged mice.

CLINICAL RELEVANCE

Aging promotes the progression of muscle degeneration in a mouse RCT model. Furthermore, this study shows that muscle degeneration occurs in aged mice even without denervation and that the model described in the present study is a useful tool for studying the pathology of muscle degeneration.

Blocking screw augmentation in intramedullary nailing for displaced surgical neck fractures of the proximal humerus

A displaced surgical neck fracture can be a good indication for antegrade intramedullary nailing. However, nail insertion may result in malreduction and translational displacement of the humeral head fragment because of muscle traction and size discrepancies between the diameters of the medullary canal and the intramedullary nail. We used blocking screw augmentation in 20 fractures with residual medial displacement of the distal fragment after nail insertion to anatomically reduce displacement of the fracture and to maintain the reduced position before bone union. A blocking screw was placed percutaneously at the lateral side of the canal. Next, a straight intramedullary nail was reinserted medial to the blocking screw. Finally, the nail was locked both proximally and distally. All cases showed bone union without fixation failure at the time of the final follow-up. Blocking screw augmentation with intramedullary nailing is feasible for the treatment of humeral surgical neck fractures and is thought to be helpful for fracture reduction during surgery and stable fixation after surgery.

Risk Factors for Loss of Active Shoulder Range of Motion in Massive Rotator Cuff Tears

Background:

Patients with massive rotator cuff tears often exhibit loss of active range of shoulder motion, which can interfere with activities of daily living. The risk factors for loss of motion remain largely unknown.

Purpose:

To clarify the predictive factors that affect the range of motion in chronic massive rotator cuff tears using multivariate analyses.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

The authors retrospectively reviewed 204 consecutive patients who were evaluated at their institution with chronic massive rotator cuff tears. In this study, the dependent variable was determined to be active anterior elevation limited to ≤90° or external rotation (ER) with the arm at the side limited to ≤0°. Explanatory variables included age; sex; affected side; duration of symptoms; smoking history; existence of diabetes, hypertension, or rheumatoid arthritis; involved tendons; presence of a 3-tendon tear; rupture of the long head of biceps tendon; superior migration of the humeral head; and cuff tear arthropathy. Baseline variables that were observed to be significant in the univariate analyses were included in multivariate models, which used logistic regression to identify independent predictors of loss of motion.

Results:

Overall, 73 patients (35.8%) exhibited limited anterior elevation, and 27 (13.2%) exhibited limited ER. Multivariate analyses showed that inferior subscapularis tear (odds ratio [OR], 14.66; 95% CI, 2.95-72.93; P = .001), smoking (OR, 4.13; 95% CI, 1.94-8.79; P < .001), superior migration of humeral head (OR, 3.92; 95% CI, 1.80-8.53; P = .001), and 3-tendon tear (OR, 3.29; 95% CI, 1.32-8.20; P = .011) were significantly associated with the loss of anterior elevation. Teres minor tear (OR, 73.37; 95% CI, 9.54-564.28; P < .001) and superior migration of the humeral head (OR, 3.55; 95% CI, 1.04-12.19; P = .044) were significantly associated with loss of ER.

Conclusion:

In the current study, a history of smoking, type of torn tendons, and superior migration of the humeral head were associated with loss of active shoulder motion. In particular, the status of inferior subscapularis or teres minor contributed to the onset of pseudoparalysis in massive rotator cuff tears.

Change of wrist motion before and after fixation of the distal radioulnar joint and resection of the distal ulna in a cadaveric model

OBJECTIVE

Recent study suggests the distal radioulnar joint (DRUJ) plays a role in flexion and extension of the wrist. We examined the range of motion (ROM) of the wrist before and after DRUJ fixation and distal ulnar resection in a cadaveric model.

METHODS

Twenty fresh cadaveric human wrists were transected and treated with two sequential interventions: (a) DRUJ fixation, and (b) distal ulnar resection. The angle of maximum flexion and extension of the wrist was measured before and after the procedures. Maximum force to the wrist was determined before the procedures using a digital pressure monitor.

RESULTS

The mean maximum wrist flexion ROM was 84.2° before the procedures. The ROM decreased to 82.5° after DRUJ fixation, and significantly increased to 88.2° after subsequent resection of the distal ulna. The mean maximum wrist extension ROM before the procedures was 73.5°. The ROM decreased to 71.6° after DRUJ fixation, and significantly increased to 77.1° after subsequent resection of the distal ulna.

CONCLUSIONS

Motion of the wrist is affected by DRUJ. This study suggests that the DRUJ might contribute to the ROM in flexion and extension of the wrist.

Total elbow arthroplasty using an augmented reality-assisted surgical technique

BACKGROUND

Precision placement of implants in total elbow arthroplasty (TEA) using conventional surgical techniques can be difficult and riddled with errors. Modern technologies such as augmented reality (AR) and 3-dimensional (3D) printing have already found useful applications in many fields of medicine. We proposed a cutting-edge surgical technique, augmented reality total elbow arthroplasty (ARTEA), that uses AR and 3D printing to provide 3D information for intuitive preoperative planning. The purpose of this study was to evaluate the accuracy of humeral and ulnar component placement using ARTEA.

METHODS

Twelve upper extremities from human frozen cadavers were used for experiments performed in this study. We scanned the extremities via computed tomography prior to performing TEA to plan placement sites using computer simulations. The ARTEA technique was used to perform TEA surgery on 6 of the extremities, whereas conventional (non-ARTEA) techniques were used on the other 6 extremities. Computed tomography scanning was repeated after TEA completion, and the error between the planned and actual placements of humeral and ulnar components was calculated and compared.

RESULTS

For humeral component placement, the mean positional error ± standard deviation of ARTEA vs. non-ARTEA was 1.4° ± 0.6° vs. 4.4° ± 0.9° in total rotation (P = .002) and 1.5 ± 0.6 mm vs. 8.6 ± 1.3 mm in total translation (P = .002). For ulnar component placement, the mean positional error ± standard deviation of ARTEA vs. non-ARTEA was 5.5° ± 3.1° vs. 19.5° ± 9.8° in total rotation (P = .004) and 1.5 ± 0.4 mm vs. 6.9 ± 1.6 mm in total translation (P = .002). Both rotational accuracy and translational accuracy were greater for joint components replaced using the ARTEA technique compared with the non-ARTEA technique (P < .05).

CONCLUSION

Compared with conventional surgical techniques, ARTEA had greater accuracy in prosthetic implant placement when used to perform TEA.

Nonunion of the coracoid process: a systematic review

INTRODUCTION

Although the coracoid process seems to play an important anatomical role, there are few reports concerning fracture nonunion of the coracoid process (CN) and its disorders. Therefore, there is no widely accepted standard for the treatment of CN.

MATERIALS AND METHODS

PubMed and Scopus were searched using "scapular fracture" and "coracoid fracture" as search terms. The inclusion criteria were English full-text articles concerning coracoid fracture, and articles that described patient characteristics and presented appropriate images. The exclusion criteria were descriptive cases, and cases without appropriate images. Citation tracking was conducted to find additional articles and notable full-text articles written in other languages. Fractures were classified using Ogawa's functional classification, with Eyres' anatomical classification used as a supplement when necessary.

RESULTS

Twenty-nine patients (26 men, 3 women) with 30 CN were identified. Nine CN had a predisposing factor such as seizure disorder and renal osteodystrophy. The fracture types were 12 Ogawa type I and 18 type II. Concurrent shoulder girdle injuries at the time of initial trauma/accident were varied. There were six cases of double disruption and two of triple disruption of the superior shoulder suspensory complex (SSSC), all of which had Ogawa type I fracture. Only six CN were isolated. The most frequent cause of CN was oversight by the previous physician (n = 11), followed by conservative treatment (n = 7). Although 12 patients with 13 CN had symptoms attributable to CN, most of these symptoms were insignificant. Although the acromioclavicular dislocation or CN persisted in eight patients, these residual abnormalities did not significantly affect the outcomes.

CONCLUSIONS

Physicians treating CN should recognize that CN itself is frequently asymptomatic, and a satisfactory outcome is achieved solely by treating the concurrent injuries, even if CN remains. When CN is suspected to produce symptoms, the physician must then determine the mechanism by which the symptoms are produced, and select a treatment strategy.

LEVEL OF EVIDENCE

V.

Evaluation of Dynamic Carpal Arch Stability following Carpal Tunnel Release Using Four-Dimensional Computed Tomography

Introduction  This study aimed to assess the carpal arch dynamics during active finger and wrist motion following carpal tunnel release using four-dimensional computed tomography (4D-CT). Materials and Methods  Four patients who diagnosed with bilateral carpal tunnel syndrome and underwent unilateral carpal tunnel release were prospectively included. 4D-CT of the bilateral wrists during active finger and wrist motion was performed for 10 seconds at five frames per second. The distances between the tip of tuberosity of the scaphoid and the volar ridge of the pisiform (S-P distance) and volar ridge of trapezium and the tip of hook of hamate (T-H distance) were measured at each position and the values of S-P and T-H distances were compared between the postoperative and contralateral wrists. Results  During finger motion, the S-P and T-H distances were not different at any position between the postoperative side and contralateral side. Conversely, S-P and T-H distances gradually increased in the postoperative wrists. The differences between the sides of S-P distance were significant, with >0 degrees of wrist extension, and differences of T-H distance were significant with >15 degrees of wrist extension. Conclusion  This study demonstrated the carpal arch dynamics using 4D-CT and revealed that the carpal arch was widened with the wrist in extension after carpal tunnel release. This study suggests that the transverse carpal ligament plays an important role in maintaining carpal arch stability.

Residual coracoclavicular separation after plate fixation for distal clavicle fractures: comparison between fracture patterns

Background

Plate fixation is an established treatment for Neer type II and V distal clavicle fractures; however, residual coracoclavicular (C-C) separation after osteosynthesis for unstable distal clavicle fractures has rarely been discussed. This study aimed to reveal the extent of postoperative C-C separation after plate fixation for distal clavicle fractures and to evaluate the relationship between residual C-C separation and the risk of postoperative complications.

Methods

We retrospectively reviewed 60 patients with a displaced distal clavicle fracture that was treated with a Scorpion plate without C-C reconstruction and successfully united. Distal clavicle fractures were divided as per the Neer classification into type IIA (12 patients), IIB (36 patients), and V (12 patients) groups. The modified C-C distance ratio at the time of injury and after bone union, and the postoperative complications (plate-related pain, delayed union, infection, and contracture) were compared among the three groups.

Results

The mean postoperative modified C-C distance ratio was 115.0% ± 12.0%; this ratio was significantly larger in the type IIB and V groups than in the type IIA group (P = .021 and P = .006, respectively). However, there was no significant difference in the frequency of postoperative complications among the three groups.

Conclusions

Our study demonstrated that a certain degree of C-C separation remained after plate fixation for Neer type II and V distal clavicle fractures, even when bone union was achieved. The postoperative residual C-C separation was greater for the type IIB and V groups than for the type IIA group; however, this difference may not affect postoperative complications.

Fractures of the coracoid process: a systematic review

Background

Although fracture of the coracoid process (CF) used to be considered rare, it is now more commonly encountered due to increased awareness and advances in imaging methods. This review aimed to analyze reported cases of CF to determine its mechanism and appropriate treatment.

Methods

PubMed and Scopus were searched using the terms "scapula fracture" and "coracoid fracture." The inclusion criteria were English full-text articles concerning CF that described patient characteristics with appropriate images. The exclusion criteria included cases without appropriate images and those with physeal injury or nonunion. Citation tracking was conducted to find additional articles and notable full-text articles in other languages. Fractures were mainly classified using Ogawa's classification.

Results

Ninety-seven studies were identified, including 197 patients (131 men, 33 women; average age 37.0±16.9 years). CF was classified as type I in 77%, type II in 19%, and avulsion fracture at the angle in 5%. Concurrent shoulder girdle injuries included acromioclavicular injury in 33%, clavicular fracture in 17%, acromion or lateral scapular spine fracture in 15%, and anterior shoulder instability in 11%. Among patients with type I CF, 69% had multiple disruptions of the superior shoulder suspensory complex. Conservative treatment was applied in 71% of isolated type I CF, while surgical treatment was applied in 76% of type I CF with multiple disruptions. Although the evaluation methods varied, 60% of patients were followed up for more than 6 months, and the outcomes were generally satisfactory for both conservative and surgical treatments.

Conclusion

CF occurred commonly in the age group with higher social activity. The most common fracture type was type I. The possible mechanism of CF is violent traction of the attached muscles, except for avulsion fracture at the angle. Type I CF with multiple disruptions of the superior shoulder suspensory complex requires surgical treatment, whereas conservative care is recommended for isolated type I and type II CFs.

Motion of the distal radioulnar joint in extension and flexion of the wrist using axial CT imaging of healthy volunteers

BACKGROUND

The midcarpal joint and the radiocarpal joint contribute to the extension and flexion of the wrist. Little is known about the contribution of the distal radioulnar joint (DRUJ) to the extension and flexion of the wrist. This study evaluated the ulnar motion in extension and flexion of the wrist using computed tomography (CT) imaging.

METHODS

A total of 30 wrists of healthy volunteers were enrolled. CT images of the axial sections of the DRUJ were obtained with 3 different positions of the wrist: 0° of extension (straight position), maximum active extension, and maximum active flexion. Each wrist motion was performed with 3 different forearm positions: neutral, pronation, and supination. Ulnar position at the DRUJ level was measured and ulnar position with the wrist in straight position was defined as baseline. The ulnar position was recorded as positive value when the position of the ulnar head was volar side and negative value when the position of the ulnar head was dorsal side. The difference from baseline in a position of maximum extension and flexion was evaluated.

RESULTS

In forearm neutral position and pronation, a value of ulnar position in maximum wrist flexion is significantly negative compared to that in the wrist straight position: the ulnar head moved dorsally from the wrist straight position to wrist flexion. In forearm supination, a value of ulnar position in maximum wrist extension is significantly positive compared to that in the wrist straight position: the ulnar head moved to the volar side from the wrist straight position to wrist extension.

CONCLUSIONS

The ulnar head moves during extension and flexion of the wrist. The direction of the ulnar motion was different according to the wrist and forearm position.

Osteosynthesis Using the Anatomical Plate With Grasping Arms for Unstable Distal Clavicle Fractures: A Technical Trick and Clinical Experience

SUMMARY

Plate fixation is an established method of treating distal clavicle fractures. However, it is often difficult to maintain the reduction of distal fragments with conventional plates, especially in cases where the distal fragments are small or comminuted. This study aimed to introduce a technical trick and clinical experience of osteosynthesis using an anatomical nonlocking plate with grasping arms (SCORPION NEO plate) for unstable distal clavicle fractures. During fixation, distal fragments are grasped by the plate arms and fixed with 2 screws. We retrospectively reviewed 41 patients who underwent osteosynthesis for unstable distal clavicle fractures (Neer type 2 and 5) using a SCORPION NEO plate. Patients were divided into 2 groups: type unstable 1, where the trapezoid ligament adhered to a distal fragment, and type unstable II (UII), where the trapezoid ligament adhered to a third fragment detached from a distal fragment. Although delayed union, plate loosening, plate-related pain, infection, and stiffness were observed in 2 (4.9%), 2 (4.9%), 3 (7.3%), 1 (2.4%), and 1 patient (2.4%), respectively; all fractures united at the time of final follow-up. Operating time for the UII group was significantly longer than that for the UI group. There were no significant differences between the 2 groups in postoperative complications and coracoclavicular distance ratios at the time of bone union. Our results demonstrated that osteosynthesis with the anatomical plate with grasping arms could be a viable option in the treatment of unstable distal clavicle fractures, especially in cases where distal fragments are not contiguous with the trapezoid ligament.

Risk factors and prognosis of humeral head inferior subluxation in proximal humeral fractures after osteosynthesis

Background

Humeral head inferior subluxation often occurs immediately after osteosynthesis for proximal humeral fracture; however, the underlying cause remains largely unknown. In addition, the prognosis of postoperative inferior subluxation has not been fully investigated. This study aimed to clarify the predictive factors that affected the onset of postoperative inferior subluxation using multivariate analysis and examine the postoperative course of inferior subluxation and its influence on postoperative outcomes.

Methods

We retrospectively reviewed 212 patients who underwent osteosynthesis for Neer 2- or 3-part proximal humeral fractures. In the multivariate analysis, the dependent variable was set as the inferior subluxation observed 1 week after the surgery. The explanatory variables included age, sex, affected side, body mass index, smoking, local osteoporosis, preoperative axillary nerve injury, time from injury to surgery, fracture dislocation, fracture pattern, preoperative inferior subluxation, surgical procedure, surgical approaches, blood loss, operative time, and postoperative drainage. Baseline variables, which were observed to be significant in the univariate analysis, were included in multivariate models. Furthermore, based on the presence of inferior subluxation at 1 week after the surgery, we divided the patients into two groups: with inferior subluxation (+IS group) and without inferior subluxation (−IS group). We compared the postoperative outcomes (incidence of postoperative complications and range of motion) between these two groups.

Results

Of 212 patients, 64 (30.7%) experienced inferior subluxation at 1 week after the surgery. On multivariate analyses, preoperative inferior subluxation (odds ratio = 4.69; 95% confidence interval = 2.45-9.76; P < .001) and longer operative time (odds ratio = 1.01; 95% confidence interval = 1.00-1.02; P = .049) were the risk factors for postoperative inferior subluxation. In the +IS group, inferior subluxation resolved at 1 year after the surgery in 89.5% of patients. There was no significant difference in the postoperative outcome between the +IS and −IS groups. However, four of six patients with persistent inferior subluxation, more than 6 months after the surgery, experienced complications, such as varus angulation of the humeral head or screw joint perforation.

Conclusions

This study provides new information on the risk factors for and prognosis of postosteosynthesis inferior subluxation in patients with proximal humeral fracture. Longer operative time and presence of preoperative inferior subluxation was associated with an increased risk of postoperative inferior subluxation, although it was temporary in most cases, and had no significant influence on the postoperative outcomes. However, in patients with persistent inferior subluxation of more than 6 months duration, inferior subluxation may be related to postoperative complications.

Factors related to large bone defects of bipolar lesions and a high number of instability episodes with anterior glenohumeral instability

Background

Significant bone defects are associated with poor clinical results after surgical stabilization in cases of glenohumeral instability. Although multiple factors are thought to adversely affect enlargement of bipolar bone loss and increased shoulder instability, these factors have not been sufficiently evaluated. The purpose of this study was to identify the factors related to greater bone defects and a higher number of instability episodes in patients with glenohumeral instability.

Methods

A total of 120 consecutive patients with symptomatic unilateral instability of the glenohumeral joint were retrospectively reviewed. Three-dimensional surface-rendered/registered models of bilateral glenoids and proximal humeri from computed tomography data were matched by software, and the volumes of bone defects identified in the glenoid and humeral head were assessed. After relationships between objective variables and explanatory variables were evaluated using bivariate analyses, factors related to large bone defects in the glenoid and humeral head and a high number of total instability episodes and self-irreducible dislocations greater than the respective 75th percentiles were evaluated using logistic regression analyses with significant variables on bivariate analyses.

Results

Larger humeral head defects (P < .001) and a higher number of total instability episodes (P = .032) were found to be factors related to large glenoid defects. On the other hand, male sex (P = .014), larger glenoid defects (P = .015), and larger number of self-irreducible dislocations (P = .027) were related to large humeral head bone defects. An increased number of total instability episodes was related to longer symptom duration (P = .001) and larger glenoid defects (P = .002), and an increased number of self-irreducible dislocations was related to larger humeral head defects (P = .007).

Conclusions

Whereas this study showed that bipolar lesions affect the amount of bone defects reciprocally, factors related to greater bone defects differed between the glenoid and the humeral head. Glenoid defects were related to the number of total instability episodes, whereas humeral head defects were related to the number of self-irreducible dislocations.

Differences of tensile strength in knot tying technique between orthopaedic surgical instructors and trainees

BACKGROUND

Knot tying technique is an extremely important basic skill for all surgeons. Clinically, knot slippage or suture breakage will lead to wound complications. Although some previous studies described the knot-tying technique of medical students or trainees, little information had been reported on the knot-tying technique of instructors. The objective of the preset study was to assess surgeons' manual knot tying techniques and to investigate the differences of tensile strength in knot tying technique between surgical instructors and trainees.

METHODS

A total of 48 orthopaedic surgeons (postgraduate year: PGY 2-18) participated. Surgeons were requested to tie surgical knots manually using same suture material. They were divided into two groups based on each career; instructors and trainees. Although four open conventional knots with four throws were chosen and done with self-selected methods, knot tying practice to have the appropriate square knots was done as education only for trainees before the actual trial. The knots were placed over a 30 cm long custom made smooth polished surface with two cylindrical rods. All knots were tested for tensile strength using a tensiometer. The surgical loops were loaded until the knot slipped or the suture broke. The tensile strength of each individual knot was defined as the force (N) required to result in knot failure. Simultaneously, knot failure was evaluated based on knot slippage or suture rupture. In terms of tensile strength or knot failure, statistical comparison was performed between groups using two-tailed Mann-Whitney U test or Fisher exact probability test, respectively.

RESULTS

Twenty-four instructors (PGY6-PGY18) and 24 trainees (PGY2-PGY5) were enrolled. Tensile strength was significantly greater in trainees (83.0 ± 27.7 N) than in instructors (49.9 ± 34.4 N, P = 0.0246). The ratio of slippage was significantly larger in instructors than in trainees (P < 0.001). Knot slippage (31.8 ± 17.7 N) was significantly worse than suture rupture (89.9 ± 22.2 N, P < 0.001) in tensile strength.

CONCLUSIONS

Mean tensile strength of knots done by trainees after practice was judged to be greater than that done by instructors in the present study. Clinically, knot slippage can lead to wound dehiscence, compared to suture rupture.

Retinoic Acid Receptor Agonists Suppress Muscle Fatty Infiltration in Mice

BACKGROUND

The infiltration of fat tissue into skeletal muscle, a condition referred to as muscle fatty infiltration or fatty degeneration, is regarded as an irreversible event that significantly compromises the motor function of skeletal muscle.

PURPOSE

To investigate the effect of retinoic acid receptor (RAR) agonists in suppressing the adipogenic differentiation of fibroadipogenic progenitors (FAPs) in vitro and fatty infiltration after rotator cuff tear in mice.

STUDY DESIGN

Controlled laboratory study.

METHODS

FAPs isolated from mouse skeletal muscle were cultured in adipogenic differentiation medium in the presence or absence of an RAR agonist. At the end of cell culture, adipogenic differentiation was evaluated by gene expression analysis and oil red O staining. A mouse model of fatty infiltration-which includes the resection of the rotator cuff, removal of the humeral head, and denervation the supraspinatus muscle-was used to induce fatty infiltration in the supraspinatus muscle. The mice were orally or intramuscularly administered with an RAR agonist after the surgery. Muscle fatty infiltration was evaluated by histology and gene expression analysis.

RESULTS

RAR agonists effectively inhibited the adipogenic differentiation of FAPs in vitro. Oral and intramuscular administration of RAR agonists suppressed the development of muscle fatty infiltration in the mice after rotator cuff tear. In accordance, we found a significant decrease in the number of intramuscular fat cells and suppressed expression in adipogenic markers. RAR agonists also increased the expression of the transcripts for collagens; however, an accumulation of collagenous tissues was not histologically evident in the present model.

CONCLUSION

Muscle fatty infiltration can be alleviated by RAR agonists through suppressing the adipogenic differentiation of FAPs. The results also suggest that RAR agonists are potential therapeutic agents for treating patients who are at risk of developing muscle fatty infiltration. The consequence of the increased expression of collagen transcripts by RAR agonists needs to be clarified.

CLINICAL RELEVANCE

RAR agonists can be used to prevent the development of muscle fatty infiltration after rotator cuff tear. Nevertheless, further studies are mandatory in a large animal model to examine the safety and efficacy of intramuscular injection of RAR agonists.

Risk factors for failure of reduction of anterior glenohumeral dislocation without sedation

BACKGROUND

Although anterior glenohumeral dislocations are common, the reduction procedure is often difficult, requiring sedation or anesthesia. To date, the risk factors for reduction failure without sedation have not been fully investigated. This study aimed to clarify the predictive factors that render the reduction of anterior glenohumeral dislocation without sedation difficult by use of multivariate analyses.

METHODS

We retrospectively reviewed 156 patients who underwent attempted reduction of anterior glenohumeral dislocation between 2006 and 2019. Patients were included based on the following criteria: traumatic dislocation, undergoing attempted reduction using the traction-countertraction method, and acute dislocation in which reduction was attempted within 2 days of the injury. The dependent variable was set as an irreducible glenohumeral dislocation without sedation, which was defined as a reduction failure in this study. Explanatory variables included age, sex, side of injury, recurrent dislocation, axillary nerve injury, time from dislocation to attempted reduction, greater tuberosity fracture, humeral neck fracture, glenoid rim fracture, and glenohumeral osteoarthritis. We evaluated these outcomes from radiographs and clinical notes. Univariate and multivariate analyses were performed. Baseline variables, which were observed to be significant in the univariate analysis, were included in multivariate models, which used logistic regression to identify independent predictors of reduction failure.

RESULTS

Of the 156 patients, 25 (16.0%) experienced reduction failure. Multivariate analyses showed that older age (≥55 years) (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.1-10.4; P = .036), greater tuberosity fractures (OR, 3.6; 95% CI, 1.1-12.2; P = .033), and glenoid rim fractures (OR, 11.5; 95% CI, 1.5-87.7; P = .018) were risk factors for reduction failure.

CONCLUSIONS

Our results demonstrated that multiple factors were associated with unsuccessful reduction of anterior glenohumeral dislocation without sedation. In elderly patients or patients with concurrent greater tuberosity fractures and glenoid rim fractures, reduction failure could occur in the absence of sedation; thus, the administration of sedatives or anesthesia should be considered.