Surgical treatment options for articular cartilage defects of the glenohumeral joint: A systematic review

Background

Many joint-preserving surgical interventions for cartilage defects of the knee have been adapted for use in the shoulder; however, there still exists no clear consensus for treatment. Thus, the purpose of this systematic review was to evaluate the outcomes of different interventions in patients with focal chondral lesions of the glenohumeral joint.

Methods

A literature search was conducted using PubMed, Embase, and Medline. Patients who underwent a joint-preserving surgical procedure to treat a focal chondral defect of the glenoid, humeral head or both were included. Patients treated for diffuse cartilage defects or with shoulder arthroplasty were excluded.

Results

Ten studies were included, with follow-up data available for 194 shoulders. Eight joint-preserving procedures were evaluated, with microfracture being the most common. One study evaluating microfracture reported significant improvements in patient-reported outcomes at short-term and long-term follow-up compared to preoperative scores. Across all studies, 32 patients underwent subsequent shoulder surgery, with 22 being arthroplasties.

Conclusions

We found improvements in patient-reported and functional outcomes across all studies. Although joint-preserving procedures have shown reasonable outcomes for focal chondral defects of the glenohumeral joint, long-term outcomes remain unknown, and the progression of osteoarthritis remains a concern. Higher quality evidence is required to make definitive recommendations.

Level of Evidence

IV.

Pediatric and Adolescent Shoulder Instability

PURPOSE OF REVIEW

Traumatic and atraumatic shoulder instability is common in pediatric and adolescent patients. It is well-established that young patients with anterior shoulder dislocation are at high risk of recurrent instability. This review assesses the current literature pertaining to management of both anterior instability and MDI in the pediatric and adolescent populations.

RECENT FINDINGS

Current research suggests that pediatric and adolescent patients with shoulder instability have excellent outcomes following arthroscopic Bankart repair; however, higher rates of recurrent instability requiring revision surgical management have been identified in patients with more than one dislocation episode pre-operatively, those with Hill-Sachs lesions and those under age 16. The addition of the remplissage procedure to an arthroscopic Bankart repair may be useful in preventing recurrent instability for patients with large Hill-Sachs lesions. Open procedures with bony glenoid augmentation may be indicated in patients with significant glenoid bone loss, or those who have failed primary surgical management, with promising outcomes reported following the Latarjet coracoid process transfer procedure in the adolescent population. Pediatric and adolescent patients with hyperlaxity, and those participating in swimming or gymnastics are more likely to have multidirectional instability (MDI). Non-surgical management with physical therapy is the mainstay of treatment for MDI with positive outcomes reported overall. In young patients with MDI who continue to have symptoms of instability and pain that effects daily activities or sports despite an adequate and appropriate course of rehabilitation, surgical management with capsulorrhaphy may be considered, with promising outcomes reported for both open and arthroscopic techniques. Attentive selection of timing and surgical procedure for pediatric and adolescent patients with anterior shoulder instability may help to prevent recurrent instability following shoulder stabilization. Although most pediatric and adolescent patients with MDI do well following non-surgical management alone, those that fail conservative management have good outcomes following arthroscopic or open capsulorrhaphy.

Is sling immobilization necessary after open Latarjet surgery for anterior shoulder instability? A randomized control trial

BACKGROUND

There is a current lack of knowledge regarding optimal rehabilitation and duration of sling immobilization after an open Latarjet procedure. A shift towards immediate self-rehabilitation protocols in shoulder surgery is observed to avoid postoperative stiffness and fasten return to sport. Avoiding sling immobilization could further simplify rehabilitation and provide an even faster return to activities of daily living and enhance patient satisfaction.

METHODS

This study is a single-center, randomized control trial. Sixty-eight patients will be instructed with the same standardized immediate postoperative self-rehabilitation protocol. Patients will be allocated 1:1 between a sling immobilization group for the first three postoperative weeks and no sling group without postoperative immobilization. The primary endpoint will be functional outcome at 6 months postoperative evaluated by the disease-specific Rowe score. Secondary endpoints will include baseline, 1.5-, 6-, and 12-month single assessment numeric evaluation (SANE) of instability score and visual analog pain scale (VAS). At the 6-month time point, graft bony union and position will be assessed by computed tomography. Motion capture technology will evaluate the baseline and 6-month postoperative range of motion. Finally, time to return to work and sport during the first postoperative year, along with patient satisfaction at one postoperative year, will also be recorded.

DISCUSSION

This study will allow further insights into the optimal rehabilitation protocol after open Latarjet surgery and enhance patient care by helping identify rehabilitation and coracoid graft-related factors influencing functional outcomes, bony union, range of motion, and patient satisfaction.

TRIAL REGISTRATION

The protocol was approved by the ethical committee board (CCER 2019-02,469) in April 2020 and by ClinicalTrials.gov (Identifier: NCT04479397 ) in July 2020.

Does glenohumeral offset affect clinical outcomes in a lateralized reverse total shoulder arthroplasty?

BACKGROUND

Reverse total shoulder arthroplasty (rTSA) exhibits high rates of success and low complication rates. rTSA has undergone numerous design adaptations over recent years, and lateralization of implant components provides theoretical and biomechanical benefits in stability and range of motion (ROM) as well as decreased rates of notching. However, the magnitude of implant lateralization and its effect on these outcomes is less well understood. The purpose of this study was to evaluate how increasing glenohumeral offset affects outcomes after rTSA, specifically in a lateralized humerus + medialized glenoid implant model.

METHODS

Primary rTSA using a lateralized humeral + medialized glenoid implant model performed at a single academic institution between 2012 and 2018 were retrospectively reviewed. Patient-reported outcome (PRO) parameters and clinical outcomes including ROM were evaluated both pre- and postoperatively. Pre- and postoperative radiographs were analyzed for measurement of glenohumeral offset, defined as the acromial-tuberosity offset (ATO) distance on the anteroposterior radiograph.

RESULTS

A total of 130 rTSAs were included in the analysis, with a mean follow-up of 35 mo. The mean postoperative absolute ATO was 16 mm, and the mean delta ATO (difference from pre- to postoperatively) was 4.6 mm further lateralized. Among all study patients, improvements in all ROM parameters and all PROs were observed from pre- to postoperative assessments. When assessing for the effects of lateralization on these outcomes, multivariate analysis failed to reveal a significant effect from the absolute postoperative ATO or the delta ATO on any outcome parameter.

CONCLUSIONS

rTSA using a lateralized humeral + medialized glenoid implant model exhibits excellent clinical outcomes in ROM and PROs. However, the magnitude of lateralization as measured radiographically by the ATO did not significantly affect these outcomes; patients exhibited universally good outcomes irrespective of the degree of offset restoration.

Patients with recurrent anterior shoulder instability exhibit altered glenohumeral and scapulothoracic joint kinematics during upper limb movement: A prospective comparative study

BACKGROUND

Altered shoulder kinematics in patients with recurrent anterior shoulder instability remains poorly understood. This prospective study aimed to quantify in vivo glenohumeral and scapulothoracic joint kinematics and joint-contact positions in patients with shoulder instability and healthy controls.

METHODS

Twenty patients with recurrent anterior shoulder instability (mean 28 years) and five patients without shoulder pathology (mean 39 years) were scanned using open CT in six static upper limb positions including 90° of abduction, combined abduction and external rotation, 90° of flexion, lift-off position (i.e. reaching behind the back) and the neutral shoulder with external rotation. Image datasets were digitally reconstructed to quantify shoulder joint kinematics and glenohumeral translation.

FINDINGS

At 90° of abduction, instability patients demonstrated significantly less glenohumeral abduction and a reciprocal increase in upward scapulothoracic rotation compared to controls (mean difference: 13.3°, p = 0.038). With the shoulder in combined abduction and external rotation, instability patients showed a significant increase in glenohumeral rotation and a reciprocal decrease in scapulothoracic rotation compared to controls (mean difference: 5.0°, p = 0.042). There were no significant differences in humeral head translation in the sagittal plane (anterior-posterior axis) for all motions tested (p > 0.05).

INTERPRETATION

Scapulothoracic and glenohumeral kinematics are significantly different between patients with recurrent anterior shoulder instability and those with a healthy shoulder. Instability patients compensate for reduced glenohumeral function during abduction by increasing scapular rotation. With the shoulder in combined abduction and external rotation position, greater glenohumeral joint angles without significantly increased humeral head translation suggest altered neuromuscular control in the unstable shoulder.

Glenohumeral Instability and Arm Pain in Overhead Throwing Athletes: A Correlational Study

Background

The overhead activity of throwing a baseball is arguably the most demanding athletic endeavor placed on the glenohumeral (GH) joint. Previous studies illustrate that 75-80% of baseball players will experience some degree of upper extremity (UE) pain. GH instability is thought to play a role.

Purpose

The purpose of this study was to investigate the relationship between GH joint hypermobility and instability with measures of arm pain and performance in overhead throwing athletes.

Methods

Actively competing baseball pitchers were recruited and evaluated once with the anterior-posterior Load and Shift examination procedure, the Kerlan-Jobe Orthopedic Clinic Shoulder and Elbow Questionnaire (KJOC), and the Functional Arm Scale for Throwers (FAST). Multivariate analysis was performed to identify correlation between severe GH capsular laxity (GH instability), mild capsular laxity (GH hypermobility), no capsular laxity (GH normal), and presence of shoulder pain when pitching.

Study Design

Cross-sectional Study.

Results

Forty-five pitchers were evaluated, 62.2% of throwing shoulders were classified normal stability, 26.7% were classified hypermobile, and 11.1% were classified unstable. Average KJOC scores for pitchers with the three mobility categories were 66.1 (normal), 59.7 (hypermobile), and 45.0 (unstable). Average FAST scores among the pitchers were 19.9 (normal), 34.2 (hypermobile), and 32.2 (unstable). Pitchers with GH instability and GH hypermobility demonstrated increased arm pain compared to athletes with normal GH joints; KJOC scores of 3.2, 5.5, and 7.4 (p = 0.0007), respectively.

Conclusion

Pitchers with GH instability and hypermobility demonstrated significantly increased ratings of arm pain compared to pitchers with no capsular laxity.

Level of Evidence

3b.

Concomitant glenohumeral injuries in patients with distal clavicle fractures undergoing arthroscopic-assisted surgery: a systematic review

Background

To determine the incidence of concomitant intra-articular glenohumeral injuries in patients undergoing surgical management from distal clavicle fractures (DCF) with shoulder arthroscopy and their impact on outcome.

Methods

This systematic review was conducted following the PRISMA guidelines. PubMed, EMBASE, and Virtual Health Library databases were accessed in October 2021. All the clinical studies evaluating the surgical management of DCF and using concomitant intra-operatory shoulder arthroscopy were included. Studies that did not specify the concomitant injury type were not eligible. Data from the incidence of intra-articular glenohumeral injuries, injury type, length of the follow-up, and clinical outcomes were retrieved. The quantitative content assessment was performed using the STROBE statement checklist. Evaluation of the publication bias of the included studies was performed using the risk of bias assessment tool for systematic reviews.

Results

Data from five retrospective and five prospective cohort studies were analyzed. Eight of the included studies were conducted on patient cohorts with Neer type II injuries. Data pooling revealed a mean of 17.70% of concomitant glenohumeral injuries, whereas 84.21% of them required additional surgical management (Table 1). Rotator cuff injuries, labral tears, and biceps pulley lesions were the most common concomitant injuries.

Conclusion

Preoperative MRI or diagnostic arthroscopy to evaluate glenohumeral associated injuries to DCF should be recommended.

The Outcomes of Soft-Tissue Repair for Posterior Shoulder Instability Surgery

BACKGROUND

This study aimed to assess the results after soft-tissue posterior instability surgery and address possible challenges during these operations.

METHODS

The databases of two tertiary hospitals were reviewed to identify patients treated for posterior shoulder instability between 2000 and 2015. Out of 198 treated patients, 19 cases underwent surgery with a mean follow-up of 35 months. Chart review was performed to obtain recurrence rates, revision rates, return to sport, persistent pain, subjective instability, subjective feeling of being better, complications, and range of motion after operative treatment of posterior shoulder instability. These outcomes were compared using the Fisher's exact and Mann-Whitney U tests.

RESULTS

After surgery, 6 (32%) patients had a recurrent subluxation, and 11 (58%) cases had persistent pain; moreover, 5 (26%) patients had a persistent feeling of instability, and 10 (53%) cases did not feel improvement after the operation. Furthermore, 10 (53%) patients required a revision, and there were 7 (37%) cases with a complication. Postoperatively, 75% of the patients had a full forward flexion, and 93% of the cases had full internal rotation; however, 64% of them had restrictions in external rotation.

CONCLUSION

There is a high rate of recurrent instability, need for revision, and complications after soft-tissue posterior instability surgery. Postoperative external rotation was impaired in most patients. Patients should be informed about these unsatisfactory results.

Kinematics and biomechanical validity of shoulder joint laxity tests as diagnostic criteria in multidirectional instability

BACKGROUND

Clinical laxity tests are commonly used together to identify individuals with multidirectional instability (MDI). However, their biomechanical validity in distinguishing distinct biomechanical characteristics consistent with MDI has not been demonstrated.

OBJECTIVE

To determine if differences in glenohumeral (GH) joint laxity exist between individuals diagnosed with multidirectional instability (MDI) and asymptomatic matched controls without MDI.

METHODS

Eighteen participants (9 swimmers with MDI, 9 non-swimming asymptomatic matched controls without MDI) participated in this observational study. Participants were classified as having MDI with a composite laxity score from three laxity tests (anterior/posterior drawer and sulcus tests). Single plane dynamic fluoroscopy captured joint motion with 2D-3D joint registration to derive 3D joint kinematics. Average GH translations occurring during the laxity tests were compared between groups using an independent sample's t-test. The relationship of composite laxity scores to overall translations was examined with a simple linear regression. Differences of each laxity test translation between groups were analyzed with a two-way repeated measures ANOVA.

RESULTS

Mean composite translations for swimmers were 1.7 mm greater (p = 0.04, 95% Confidence Interval (CI): 0.1, 3.3 mm) compared to controls. A moderate association occurred (r² = 0.40, p = 0.005) between composite laxity scores and composite translation. Greater translations for the posterior drawer (-2.4 mm, p = 0.04, 95% CI: -0.1, -4.6) and sulcus tests (-2.7 mm, p = 0.03, 95% CI: -0.3, -5.0) existed in swimmers compared to controls.

CONCLUSION

Significant differences in composite translation existed between symptomatic swimmers with MDI and asymptomatic control participants without MDI during GH joint laxity tests. The results provide initial biomechanically based construct validity for the clinical criteria used to identify individuals with MDI.

Chronic glenohumeral dislocations treated with arthroplasty: a systematic review

Background

The aim of this systematic review was to summarize the clinical outcomes and associated predictors of outcomes for chronic glenohumeral dislocations treated with arthroplasty.

Methods

A systematic literature search was performed with Embase, PubMed, CENTRAL, BIOSIS, and CINAHL databases from the inception of these databases through January 1, 2021 to identify all articles that examined outcomes or predictors of outcomes of arthroplasty in patients with chronic glenohumeral dislocations. Studies that examined outcomes for patients with a chronic glenohumeral dislocation (≥3 weeks) treated with hemiarthroplasty, anatomic total shoulder arthroplasty, or reverse total shoulder arthroplasty were included. Those with acute or subacute dislocations (<3 weeks), fracture dislocations, and those treated with joint preserving treatment modalities were excluded.

Results

We identified 195 articles; of which, 22 (201 patients/205 shoulders) met our inclusion criteria. A total of 14 studies reported outcomes of hemiarthroplasty, 10 studies reported outcomes of anatomic total shoulder arthroplasty, and 9 studies reported outcomes of reverse total shoulder arthroplasty. All studies documented clinical improvement after arthroplasty. Among 16 studies that measured range of motion, all 16 studies demonstrated improvement in range of motion postoperatively. Thirty-one reoperations (15%) were performed across all studies.

Conclusion

We found improved clinical outcomes after arthroplasty for the treatment of chronic glenohumeral fewer dislocations at a long-term follow-up. Some evidence suggests that reverse total shoulder arthroplasty may have superior outcomes and less complications compared with hemiarthroplasty and anatomic total shoulder arthroplasty. There is insufficient evidence regarding the potential influence that duration of dislocation, direction of dislocation, addition of concomitant procedures, or humeral component retroversion have on outcomes.

Bilateral glenohumeral septic arthritis secondary to mastitis with subsequent avascular necrosis: A case report

Introduction and importance

Septic arthritis is an orthopaedic emergency. Only 3% of septic arthritis patients present with glenohumeral involvement. Polyarticular disease with shoulder involvement constitutes 1% of this group. There is currently no documented case of bilateral glenohumeral septic arthritis with avascular necrosis secondary to mastitis.

Case presentation

We present a case of a 38-year-old African woman with bilateral glenohumeral septic arthritis after management for mastitis of the left breast. She had left, then right shoulder pain, fever, and reduced range of motion, with multiple arthroscopic washouts and antibiotic therapy instituted at various hospitals by various specialists, leading to the resolution of active infection. The patient developed bilateral humeral head avascular necrosis with complete collapse as evidenced on plain radiography 4 months later, and underwent hemiarthroplasty of the right shoulder. Biopsy at operation showed no active bone infection, and inflammatory markers were not elevated. She had reduced discomfort for the following 2 years but developed increasing pain on lifting and reduced range of motion. The moderate symptoms in her left shoulder managed non-operatively had remained unchanged. There were no elevated inflammatory markers 2-years post arthroplasty.

Clinical discussion

This case presents an uncommon scenario of bilateral septic arthritis secondary to mastitis, with rapid progression to avascular necrosis in an individual with no classical risk factors for avascular necrosis, despite appropriate antibiotic treatment and surgical interventions. Advanced collapse necessitated hemiarthroplasty of the dominant right side.

Conclusion

This case highlights the need for close radiographic follow-up in atypical presentations of septic arthritis and the dilemmas in managing advanced bilateral avascular necrosis with arthroplasty in a young patient.

•

Septic arthritis is an orthopaedic emergency.

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Mortality rates for septic arthritis range from 4 to 42% in monoarticular disease and up to 50% in polyarticular involvement.

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Only 3% of septic arthritis cases are glenohumeral, with 1% being polyarticular.

•

Humeral head avascular necrosis secondary to septic arthritis is rare.

Management of atraumatic shoulder instability in physiotherapy (MASIP): a survey of physiotherapy practice

BACKGROUND

The impact of atraumatic shoulder instability (ASI) on patients can be extensive, its management complex, with a biopsychosocial approach recommended. Currently how physiotherapists manage ASI is unknown or the extent to which current clinical practice aligns with existing evidence. At the time of this study no national guidelines or consensus to direct practice existed.

METHODS

A cross-sectional electronic survey was distributed between July-September 2018, targeting UK-based physiotherapists managing shoulder pathology. Respondents were invited to describe their management of ASI, and rate their awareness and utilisation of various treatment techniques on a Likert-scale; median and interquartile ranges were calculated. Free text survey items were analysed using quantitative content analysis (QCA) to identify codes and categories. Means and percentages were calculated to summarise QCA and descriptive data.

RESULTS

Valid survey responses were analysed (n = 135). Respondents had between 2 and 39 years of physiotherapy experience (mean = 13.9 years); the majority (71.1 %) reported that ASI made up < 10 % of their caseload. Only 22.9 % (n = 31/135) of respondents reported feeling 'very confident' in managing ASI; the majority feeling 'somewhat confident' (70.4 %, n = 95/135) or 'not confident' (6.7 %, n = 9/135). The majority of respondents (59.3 %) used an ASI classification system, > 90 % citing the Stanmore Classification. Physiotherapists adapted their management according to clinical presentation, responding to differing biopsychosocial needs of the patient scenario. Most respondents (> 80 %) did not use a protocol to guide their management. Exercise was the most utilised management approach for ASI, followed by education; novel treatment strategies, including cortical rehabilitation, were also reported.

CONCLUSION

Findings indicate physiotherapists utilise a wide range of treatment strategies and respond to biopsychosocial cues when managing patients with ASI. The majority reported not being very confident in managing this condition, however only a minority use rehabilitation protocols to support their management. Some interventions that respondents reported using lacked evidence to support their use in ASI management and further research regarding effectiveness is required. Guidelines have been published since this survey; the impact of these will need evaluating to determine their effectiveness in the future.

Current concepts in anterior glenohumeral instability: diagnosis and treatment

The glenohumeral joint is the most dislocated articulation, accounting for more than 50% of all joint dislocations. The reason behind shoulder instability should be investigated in detail for successful management, and the treatment plan should be individualized for all patients. Several classification systems have been proposed for glenohumeral instability. A physical exam is mandatory no matter what classification system is used. When treating patients with anterior shoulder instability, surgeons need to be aware of the critical size of the bone loss, which is commonly seen. The glenoid track concept was clinically adopted, and the measurement of the glenoid track for surgical decision-making is recommended. Detailed assessment of existing soft tissue injury to the labrum, capsule, glenohumeral ligaments, and rotator cuff is also mandatory as their presence influences the surgical outcome. Rehabilitation, arthroscopic repair techniques, open Bankart procedure, capsular plication, remplissage, Latarjet technique, iliac crest, and other bone grafts offer the surgeon different treatment options according to the type of patient and the lesions to be treated. Three-dimensional (3D) technologies can help to evaluate glenoid and humeral defects. Patient-specific guides are low-cost surgical instruments and can be used in shoulder instability surgery. 3D printing will undoubtedly become an essential tool to achieve the best results in glenohumeral instability surgery.

Beyond Euler/Cardan analysis: True glenohumeral axial rotation during arm elevation and rotation

BACKGROUND

Based on Euler/Cardan analysis, prior investigations have reported up to 80° of glenohumeral (GH) external rotation during arm elevation, dependent on the plane of elevation (PoE). However, the subtraction of Euler/Cardan angles does not compute the rotation around the humerus' longitudinal axis (i.e. axial rotation). Clinicians want to understand the true rotation around the humerus' longitudinal axis and rely on laboratories to inform their understanding of underlying shoulder biomechanics, especially for the GH joint since its motion cannot be visually ascertained. True GH axial rotation has not been previously measured in vivo, and its difference from Euler/Cardan (apparent) axial rotation is unknown.

RESEARCH QUESTION

What is the true GH axial rotation during arm elevation and external rotation, and does it vary from apparent axial rotation and by PoE?

METHODS

Twenty healthy subjects (10 M/10 F, ages 22-66) were recorded using biplane fluoroscopy while performing arm elevation in the coronal, scapular and sagittal planes, and external rotation in 0° and 90° of abduction. Apparent GH axial rotation was computed using the xz'y'' and yx'y'' sequences. True GH axial rotation was computed by integrating the projection of GH angular velocity onto the humerus' longitudinal axis. One-dimensional statistical parametric mapping was utilized to compare apparent versus true axial rotation, axial rotation versus 0°, and detect differences in axial rotation by PoE.

RESULTS

In contrast to apparent axial rotation, true GH axial rotation does not differ by PoE and is not different than 0° during arm elevation at higher elevation angles. The spherical area between the sequence-specific and actual humeral trajectory explains the difference between apparent and true axial rotation.

SIGNIFICANCE

Proper quantification of axial rotation is important because biomechanics literature informs clinical understanding of shoulder biomechanics. Clinicians care about true axial rotation, which should be reported in future studies of shoulder kinematics.

Evolving Concepts in the Management of Shoulder Instability

BACKGROUND

Shoulder instability exists on a spectrum ranging from subtle subluxation and pain to dislocation and can be the result of a traumatic event or repetitive microtrauma. Shoulder instability can result in significant disability and often requires surgical intervention, especially amongst younger, active patient populations. The optimal treatment of shoulder instability depends on the degree of instability and concomitant pathology involving the labrum, capsule, and bony anatomy of the glenoid and humeral head. Even with surgical intervention, recurrent instability remains a relatively common and difficult problem to address.

PURPOSE

With a focus on anterior instability, the purpose of this review article is to discuss the current assessment and treatment of shoulder instability, and highlight current and future treatment modalities, as well as to identify current trends and deficiencies in our current management. We also provide an algorithm for the surgical treatment of anterior shoulder instability.

METHODS

Literature databases were extensively searched for recent articles related to the mechanism, diagnosis, and treatment of shoulder instability to comprise a comprehensive review.

CONCLUSION

Although there are multiple treatment modalities available for shoulder instability, such as nonoperative management, open and arthroscopic Bankart repair, Latarjet procedures, and remplissage, orthopaedic surgeons continue to learn about the most appropriate method of management as increasing long-term outcomes become available.

Is limited shoulder abduction associated with poor scapulothoracic mobility after reverse shoulder arthroplasty?

INTRODUCTION

The contribution of the glenohumeral joint to shoulder abduction is acknowledged as an important factor for reverse total shoulder arthroplasty (RTSA) patients. In contrast, the degree of scapulothoracic joint contribution and its relation to RTSA patients with poor to excellent shoulder abduction are unclear.

MATERIALS AND METHODS

Twenty-three selectively recruited patients (74 ± 7 years, 11 males) with shoulder abduction ranging from poor to excellent at least 6 months after primary, unilateral RTSA participated in this study. Individual scapulothoracic and glenohumeral contributions at maximum shoulder abduction in the scapular plane were measured using 3D motion capture and correlations between scapulothoracic and glenohumeral contributions to shoulder abduction were assessed. Multiple regression analysis was used to determine the influence of age, body mass index, follow-up period, abduction strength and passive glenohumeral mobility on scapulothoracic and glenohumeral function.

RESULTS

Maximum shoulder abduction (range 48°-140°) was not significantly correlated with the scapulothoracic contribution (range 39°-75°, r = 0.40, p = 0.06), but there was a strong and significant correlation with the glenohumeral contribution (range - 9°-83°, r = 0.91, p < 0.001). Abduction strength was strongly associated with glenohumeral (p = 0.006) but not scapulothoracic (p = 0.34) joint contributions.

CONCLUSIONS

Limited shoulder abduction is not associated with insufficient scapulothoracic mobility, which rather provides a basic level of function for RTSA patients. Good to excellent shoulder abduction could only be achieved by increasing the glenohumeral contribution that was associated with postoperative abduction strength.

Glenoid Bone Loss in Shoulder Instability: Superiority of Three-Dimensional Computed Tomography over Two-Dimensional Magnetic Resonance Imaging Using Established Methodology

Backgroud

Recent literature suggests that three-dimensional magnetic resonance imaging (3D MRI) can replace 3D computed tomography (3D CT) when evaluating glenoid bone loss in patients with shoulder instability. We aimed to examine if 2D MRI in conjunction with a validated predictive formula for assessment of glenoid height is equivalent to the gold standard 3D CT scans for patients with recurrent glenohumeral instability.

Methods

Patients with recurrent shoulder instability and available imaging were retrospectively reviewed. Glenoid height on 3D CT and 2D MRI was measured by two blinded raters. Difference and equivalence testing were performed using a paired t-test and two one-sided tests, respectively. The interclass correlation coefficient (ICC) was used to test for interrater reliability, and percent agreement between the measurements of one reviewer was used to assess intrarater reliability.

Results

Using an equivalence margin of 1 mm, 3D CT and 2D MRI were found to be different (p = 0.123). The mean glenoid height was significantly different when measured on 2D MRI (39.09 ± 2.93 mm) compared to 3D CT (38.71 ± 2.89 mm) (p = 0.032). The mean glenoid width was significantly different between 3D CT (30.13 ± 2.43 mm) and 2D MRI (27.45 ± 1.72 mm) (p < 0.001). The 3D CT measurements had better interrater agreement (ICC, 0.91) than 2D MRI measurements (ICC, 0.8). intrarater agreement was also higher on CT.

Conclusions

Measurements of glenoid height using 3D CT and 2D MRI with subsequent calculation of the glenoid width using a validated methodology were not equivalent, and 3D CT was superior. Based on the validated methods for the measurement of glenoid bone loss on advanced imaging studies, 3D CT study must be preferred over 2D MRI in order to estimate the amount of glenoid bone loss in candidates for shoulder stabilization surgery and to assist in surgical decision-making.

Anterior glenohumeral instability: Current review with technical pearls and pitfalls of arthroscopic soft-tissue stabilization

The glenohumeral joint (GHJ) allows for a wide range of motion, but is also particularly vulnerable to episodes of instability. Anterior GHJ instability is especially frequent among young, athletic populations during contact sporting events. Many first time dislocators can be managed non-operatively with a period of immobilization and rehabilitation, however certain patient populations are at higher risk for recurrent instability and may require surgical intervention for adequate stabilization. Determination of the optimal treatment strategy should be made on a case-by-case basis while weighing both patient specific factors and injury patterns (i.e., bone loss). The purpose of this review is to describe the relevant anatomical stabilizers of the GHJ, risk factors for recurrent instability including bony lesions, indications for arthroscopic vs open surgical management, clinical history and physical examination techniques, imaging modalities, and pearls/pitfalls of arthroscopic soft-tissue stabilization for anterior glenohumeral instability.

Endoscopic brachial plexus neurolysis in the management of infraclavicular nerve injuries due to glenohumeral dislocation

INTRODUCTION

Infraclavicular brachial plexus (BP) injury secondary to glenohumeral joint (GHJ) dislocation is a rather common complication, which may be accountable for long-lasting deficits. The purpose of this study was to assess the potential benefits of BP neurolysis in such presentation, using an endoscopic approach.

MATERIALS AND METHODS

All patients who underwent endoscopic BP neurolysis in the setting of infraclavicular BP palsy due to GHJ dislocation were included. Preoperative physical examination was conducted to classify the observed motor and sensitive deficits into nerves and/or cord lesions. Six weeks after the trauma, examination was repeated and endoscopic BP neurolysis was elected if no significant improvements were observed. If nerve ruptures and/or severe damages were identified during surgery, nerve reconstructions were conducted within a month; in other cases, follow-up examinations were conducted at 6 weeks, 3 and 6 months to assess the course of postoperative recovery.

RESULTS

Eleven patients were included, including 6 men and 5 women, with a mean age of 43 ± 23 years (16;73). Six patients had at least one cord involved, four patients had isolated axillary nerve palsy, and one patient had a complete BP palsy. In 7 patients with cord lesions and/or isolated axillary nerve palsy, at least grade-3 strength, according to the British Medical Research Council grading system, was noted in all affected muscles within 6 weeks following the neurolysis; after 3 months of follow-up, grade-4 strength was observed in all muscles, and all but patients but one had fully recovered within 6 months. In 3 patients with isolated axillary nerve palsy, complete nerve ruptures (n=2) and severe damages (n=1) were identified under scopic magnification; secondary nerve transfers were conducted to reanimate the axillary nerve, and all patients fully recovered within a year. In one patient with complete BP palsy, improvements started after 6 months of follow-up, and full recovery was yielded after 2 years. No intra- and/or postoperative complications were noted.

CONCLUSIONS

At the cost of minimal additional morbidity, endoscopic BP neurolysis appears to be a safe and reliable procedure to shorten recovery delays in most patients presenting with BP palsy due to GHJ dislocation.

Current practices in the management of anterior glenohumeral instability in rugby union players

BACKGROUND

Rugby has the highest incidence of traumatic injuries of any sport, and glenohumeral injuries result in the lengthy delay in return to play. The purpose of this study is to survey surgeons from the American Shoulder and Elbow Surgeons (ASES), and the British Elbow and Shoulder Society (BESS) to evaluate the current state of management of anterior glenohumeral instability, and compare the differences in practices.

METHODS

A survey of surgeons from ASES and BESS was conducted. Treatment options were proposed in a variety of clinical scenarios of glenohumeral instability. The time of immobilization post-operatively, return to play, and attitudes on current contact regulations. Results were compared using the chi-square test or t-test.

RESULTS

Ninety-seven surgeons responded to the survey. There was a significant difference in treatment between ASES and BESS surgeons in the setting of primary dislocation (p < 0.05), but not recurrent dislocation (p > 0.05). The period of immobilization following injury and surgery was different between both treating groups. There was a significant difference in return to play between ASES and BESS surgeons with arthroscopic stabilization and open Bankart repair (p < 0.05), but not following conservative treatment or the Latarjet procedure (p > 0.05).

CONCLUSIONS

There remains wide variance on the management of glenohumeral instability in rugby union players among surgeons. While immobilization times post-operatively were similar, the BESS surgeons were more confident in allowing earlier return to play. There is also a significant concern that contact levels should be regulated to protect player safety.

LEVEL OF EVIDENCE

Level 4 (case series).

Instantaneous helical axis estimation of glenohumeral kinematics: The impact of rotator cuff pathology

The rotator cuff is theorized to contribute to force couples required to produce glenohumeral kinematics. Impairment in these force couples would theoretically result in impaired ball-and-socket kinematics. Although less frequently used than traditional kinematic descriptors (e.g., Euler angles, joint translations), helical axes are capable of identifying alterations in ball-and-socket kinematics by quantifying the variability (i.e., dispersion) in axis orientation and position during motion. Consequently, assessing glenohumeral helical dispersion may provide indirect evidence of rotator cuff function. The purpose of this exploratory study was to determine the extent to which rotator cuff pathology is associated with alterations in ball-and-socket kinematics. Fifty-one participants were classified into one of five groups based on an assessment of the supraspinatus using diagnostic imaging: asymptomatic healthy, asymptomatic tendinosis, asymptomatic partial-thickness tear, asymptomatic full-thickness tear, symptomatic full-thickness tear. Glenohumeral kinematics were quantified during coronal plane abduction using a biplane x-ray system and described using instantaneous helical axes. The degree to which glenohumeral motion coincided with ball-and-socket kinematics was described using the angular and positional dispersion about the optimal helical axis and pivot, respectively. No statistically significant difference was observed between groups in angular dispersion. However, symptomatic individuals with a full-thickness supraspinatus tear had significantly more positional dispersion than asymptomatic individuals with a healthy supraspinatus or tendinosis. These findings suggest that symptomatic individuals with a full-thickness supraspinatus tear exhibit impaired ball-and-socket kinematics, which is believed to be associated with a disruption of the glenohumeral force couples.

Effect of rotator cuff muscle activation on glenohumeral kinematics: A cadaveric study

Healthy shoulder function requires the coordination of the rotator cuff muscles to maintain the humeral head's position in the glenoid. While glenohumeral stability has been studied in various settings, few studies have characterized the effect of dynamic rotator cuff muscle loading on glenohumeral translation during shoulder motion. We hypothesize that dynamic rotator cuff muscle activation decreases joint translation during continuous passive abduction of the humerus in a cadaveric model of scapular plane glenohumeral abduction. The effect of different rotator cuff muscle activity on glenohumeral translation was assessed using a validated shoulder testing system. The Dynamic Load profile is a novel approach, based on musculoskeletal modeling of human subject motion. Passive humeral elevation in the scapular plane was applied via the testing system arm, while the rotator cuff muscles were activated according to the specified force profiles using stepper motors and a proportional control feedback loop. Glenohumeral translation was defined according to the International Society of Biomechanics. The Dynamic load profile minimized superior translation of the humeral head relative to the conventional loading profiles. The total magnitude of translation was not significantly different (0.805) among the loading profiles suggesting that the compressive forces from the rotator cuff primarily alter the direction of humeral head translation, not the magnitude. Rotator cuff muscle loading is an important element of cadaveric shoulder studies that must be considered to accurately simulate glenohumeral motion. A rotator cuff muscle activity profile based on human subject muscle activity reduces superior glenohumeral translation when compared to previous RC loading profiles.

Obesity is Associated with an Increased Prevalence of Glenohumeral Osteoarthritis and Arthroplasty: A Cohort Study

The relationship between obesity and glenohumeral osteoarthritis is relatively understudied. The purpose of this study was to better define this relationship by age- and gender-matching 596,874 patients across six body mass index (BMI) cohorts and determining the prevalence of glenohumeral osteoarthritis and the standardized rate of glenohumeral arthroplasty in each cohort. Individuals with a BMI over 24 were found to be at increased odds for developing glenohumeral osteoarthritis, compared to the normal BMI cohort, and individuals with a BMI over 30 were additionally found to be at increased odds for undergoing glenohumeral arthroplasty.

Accuracy of unguided and ultrasound guided Coracohumeral ligament infiltrations - a feasibility cadaveric case series

BACKGROUND

Coracohumeral ligament (CHL) thickening, contracture, and fibroplasia have been identified in glenohumeral idiopathic adhesive capsulitis (GHIAC). The CHL is the main structure responsible for the range of motion limitations. Favorable outcomes have been reported with CHL surgical release. Intra-articular glenohumeral joint corticosteroid infiltrations are utilized to disrupt the inflammatory process and reduce pain in GHIAC. The aim of this study was to investigate whether the CHL could be accurately targeted with a periligamentous infiltration.

METHODS

A convenience sample of 12 unembalmed cadaver shoulders (mean age: 74.5 years, range 66-87 years) without evidence of previous injury or surgery were utilized in this exploratory double factor feasibility cadaveric (unguided and ultrasound (US) guided) case series. Two clinicians trained in musculoskeletal infiltration techniques carried out the infiltrations on each shoulder with colored latex. One clinician infiltrated without guidance, the other with US-guidance. The injecting clinicians were blinded to the others infiltration procedure and the order was randomized. An anatomist blinded to the infiltration order performed a shoulder dissection and recorded the infiltrate location. Percentage calculation for accuracy of infiltration and a chi-square evaluation of the difference between unguided and US-guided infiltrations was applied.

RESULTS

An accuracy of 75% was achieved for unguided infiltration and 80% for US-guided infiltration techniques. Chi-squared indicated there was no significant difference (p = 0.82) between the unguided and US-guided techniques.

CONCLUSION

US-guided and unguided infiltrations achieved good accuracy targeting the CHL, suggesting infiltrations can specifically and accurately target the CHL. In vivo investigation using such infiltration techniques are warranted.

A musculoskeletal modelling approach to explain sit-to-stand difficulties in older people due to changes in muscle recruitment and movement strategies

By 2050 the proportion of over 65s is predicted to be 20% of the population. The consequences of an age-related reduction in muscle mass have not been fully investigated and, therefore, the aim of the present study was to quantify the muscle and joint contact forces using musculoskeletal modelling, during a sit-to-stand activity, to better explain difficulties in performing everyday activities for older people. A sit-to-stand activity with and without the use of arm rests was observed in ninety-five male participants, placed into groups of young (aged 18-35 years), middle-aged (aged 40-60 years) or older adults (aged 65 years and over). Older participants demonstrated significantly lower knee extensor and joint forces than the young when not using arm rests, compensating through elevated hip extensor and ankle plantarflexor muscle activity. The older group were also found to have higher shoulder joint contact forces whilst using arm rests. This tendency to reorganise muscle recruitment to include neighbouring groups or other parts of the body could make everyday activities more susceptible to age-related functional decline. Reductions in leg strength, via age- or atrophy- related means, creates increased reliance on the upper body and may result in further lower limb atrophy through disuse. The eventual decline of upper body function reduces strength reserves, leading to increased vulnerability, dependence on others and risk of institutionalisation.

Imaging of Traumatic Shoulder Girdle Injuries

Shoulder girdle trauma is one of the most common injuries encountered in emergency centers. These injuries can be easily overlooked due to the complex osteology of the shoulder. Although radiographs are usually sufficient for assessing traumatic shoulder injuries, cross-sectional imaging is sometimes indicated to assess portions of the shoulder not well visualized by radiographs. In this article, the authors review the spectrum of shoulder girdle injuries: sternoclavicular dislocations, clavicle fractures, acromioclavicular separations, shoulder dislocations, scapula fractures, and scapulothoracic dissociation. They also discuss the presentation, imaging evaluation, and classification of these injuries with emphasis on pitfalls in imaging diagnosis and indications for computed tomography/magnetic resonance.

The Veil of Obscuration: Additional Radiographic Sign of Posterior Shoulder Dislocation

OBJECTIVE

To describe a new radiographic sign, "veil of obscuration", associated with posterior glenohumeral joint (shoulder) dislocations and determine its incidence and validity compared to other known classic radiographic signs.

METHODS

Four-year retrospective study identified 30 acute posterior shoulder dislocation patients. Radiographs reviewed in consensus by 2 musculoskeletal radiologists for the "veil of obscuration", seen on AP shoulder radiographs and representing a comminuted fracture of the lesser tuberosity projecting over the humeral head or glenohumeral joint. Incidence of this radiographic sign of posterior glenohumeral joint dislocation in addition to other previously described classic radiographic signs, and association with other fractures, surgery, and mechanism of injury were evaluated. Continuous data was analyzed with student t-test and categorical data with Chi-Square test.

RESULTS

There were 20 right and 10 left posterior shoulder dislocations. Majority of injuries resulted from vehicle crash (44%). In most cases, reverse Hill-Sachs lesion (83%) and fixed internal rotation of the humeral head (76%) were present, followed by trough line (43%) and "veil of obscuration" (40%). Trough line was seen in significantly more major trauma and vehicle crashes (78% and 46%; P=0.015), while "veil of obscuration" was seen in more seizures (86%; P=0.037) and in all surgical patients. No significant difference in presence of other classic radiographic signs in regards to surgery.

CONCLUSION

The newly described radiographic sign of posterior shoulder dislocations named the "veil of obscuration" has comparable incidence as other classic radiographic signs and may be useful in the recognition and diagnosis of these injuries.

Modeling a rotator cuff tear: Individualized shoulder muscle forces influence glenohumeral joint contact force predictions

BACKGROUND

Rotator cuff tears in older individuals may result in decreased muscle forces and changes to force distribution across the glenohumeral joint. Reduced muscle forces may impact functional task performance, altering glenohumeral joint contact forces, potentially contributing to instability or joint damage risk. Our objective was to evaluate the influence of rotator cuff muscle force distribution on glenohumeral joint contact force during functional pull and axilla wash tasks using individualized computational models.

METHODS

Fourteen older individuals (age 63.4 yrs. (SD 1.8)) were studied; 7 with rotator cuff tear, 7 matched controls. Muscle volume measurements were used to scale a nominal upper limb model's muscle forces to develop individualized models and perform dynamic simulations of movement tracking participant-derived kinematics. Peak resultant glenohumeral joint contact force, and direction and magnitude of force components were compared between groups using ANCOVA.

FINDINGS

Results show individualized muscle force distributions for rotator cuff tear participants had reduced peak resultant joint contact force for pull and axilla wash (P ≤ 0.0456), with smaller compressive components of peak resultant force for pull (P = 0.0248). Peak forces for pull were within the glenoid. For axilla wash, peak joint contact was directed near/outside the glenoid rim for three participants; predictions required individualized muscle forces since nominal muscle forces did not affect joint force location.

INTERPRETATION

Older adults with rotator cuff tear had smaller peak resultant and compressive forces, possibly indicating increased instability or secondary joint damage risk. Outcomes suggest predicted joint contact force following rotator cuff tear is sensitive to including individualized muscle forces.

Biomechanics of posterior shoulder instability - current knowledge and literature review

Posterior instability of the shoulder is a rare condition and represents about 10% of shoulder instability. It has become more frequently recognized in the last year, even though it is more difficult to diagnose than anterior shoulder instability. As this form of shoulder pathology is somewhat rare, biomechanical knowledge is limited. The purpose of our study was to perform an extensive literature search, including PubMed and Medline, and to give an overview of the current knowledge on the biomechanics of posterior shoulder instability. The PubMed/Medline databases were utilized, and all articles related to posterior shoulder instability and biomechanics were included to form a comprehensive compilation of current knowledge. A total of 93 articles were deemed relevant according to our inclusion and exclusion criteria. As expected with any newly acknowledged pathology, biomechanical studies on posterior shoulder instability remain limited in the literature. Current biomechanical models are performed in a static manner, which limits their translation for explaining a dynamic pathology. Newer models should incorporate dynamic stabilization of both the rotator cuff and scapulothoracic joint. There is a current lack of knowledge with regards to the pathomechanism of posterior shoulder instability, with no consensus on appropriate treatment regimens. Further investigation is therefore required at both basic science and clinical levels.

The effect of glenohumeral plane of elevation on supraspinatus subacromial proximity

Shoulder pain is a common clinical problem affecting most individuals in their lifetime. Despite the high prevalence of rotator cuff pathology in these individuals, the pathogenesis of rotator cuff disease remains unclear. Position and motion related mechanisms of rotator cuff disease are often proposed, but poorly understood. The purpose of this study was to determine the impact of systematically altering glenohumeral plane on subacromial proximities across arm elevation as measures of tendon compression risk. Three-dimensional models of the humerus, scapula, coracoacromial ligament, and supraspinatus were reconstructed from MRIs in 20 subjects. Glenohumeral elevation was imposed on the humeral and supraspinatus tendon models for three glenohumeral planes, which were chosen to represent flexion, scapular plane abduction, and abduction based on average values from a previous study of asymptomatic individuals. Subacromial proximity was quantified as the minimum distance between the supraspinatus tendon and coracoacromial arch (acromion and coracoacromial ligament), the surface area of the supraspinatus tendon within 2 mm proximity to the coracoacromial arch, and the volume of intersection between the supraspinatus tendon and coracoacromial arch. The lowest modeled subacromial supraspinatus compression measures occurred during flexion at lower angles of elevation. This finding was consistent across all three measures of subacromial proximity. Knowledge of this range of reduced risk may be useful to inform future studies related to patient education and ergonomic design to prevent the development of shoulder pain and dysfunction.

Quantitative mapping of glenohumeral cartilage in asymptomatic subjects using 3 T magnetic resonance imaging

OBJECTIVE

The purpose of this study was to develop quantitative T2 mapping methodology in asymptomatic shoulders for the entire mappable region of the glenohumeral cartilage in the coronal and sagittal planes, to assess the feasibility and limitations of the development of a diagnostic tool for future application in symptomatic patients.

MATERIALS AND METHODS

Twenty-one asymptomatic volunteers underwent sagittal and coronal glenohumeral T2 mapping, as the spherical geometry of the humeral head obviates the need to evaluate the entire glenohumeral cartilage in a single plane. The humeral head cartilage orthogonal to the mapping plane was manually segmented in the sagittal and coronal planes, whereas the glenoid cartilage was segmented in the coronal plane. Cartilage T2 summary statistics were calculated and coverage in each mapping plane was qualitatively assessed.

RESULTS

The mean ± standard deviation of the glenoid cartilage T2 was 38 ± 2 ms. The coronal and sagittal mapping planes captured different regions of the humeral head with some overlap: inferior-medial to superior-lateral versus superior/superior-lateral to anterior-lateral and posterior-lateral respectively. The mean humeral head cartilage T2 in the coronal plane was 41 ± 3 ms, which was significantly different (p < 0.05) from the sagittal plane mean of 34 ± 2 ms.

CONCLUSION

This study measured characteristic glenoid and humeral head cartilage T2 values over the area mappable with two planes. Importantly, this study demonstrated that two-dimensional mapping in a single plane or two combined planes cannot capture the entirety of the semi-spherical humeral head cartilage. This highlights the need for three-dimensional T2 mapping techniques in the shoulder.

Glenohumeral osteoarthritis: frequency of underlying diagnoses and the role of arm dominance-a retrospective analysis in a community-based musculoskeletal practice

Patients with shoulder pain are commonly seen in adult primary care, and are typically referred to musculoskeletal specialists when their symptoms are persistent. Rotator cuff disorders (RCD) most commonly underlie non-traumatic shoulder pain in adults, and glenohumeral osteoarthritis (GHOA) has been considered to be relatively uncommon (Nakagawa et al., J Shoulder Elb Surg 8:580-584, 1999). Our impression has been that GHOA affects significant numbers of patients, is less well studied, and may be under recognized. Among adults referred to a musculoskeletal practice for shoulder pain evaluation, we determined the relative numbers of patients with a clinical diagnosis of RCD and GHOA by age and by gender, assessed the role of handedness in GHOA, and the proportion of patients with underlying conditions (versus primary or idiopathic GHOA). We also assessed the frequency of progression to operative management over a defined time interval. This is a retrospective case series of patients presenting to a musculoskeletal referral practice for shoulder pain. Patients with a clinical diagnosis of GHOA were identified with electronic medical records, and then assessed for demographic data, physical measures, comorbidities, and progression to surgical intervention within 2 years. Among non-traumatic shoulder pain patients presenting to our practice during a 9-month period in 2013, RCD was diagnosed in 984 patients, and GHOA was diagnosed in 209 patients. 152 of the GHOA patients (73%) had primary (idiopathic) GHOA, without associated inflammatory conditions or cuff arthropathy. Primary GHOA affected the dominant arm in 38.7%, the non-dominant arm in 33.8%, and was bilateral in 27.5%. Patients diagnosed with primary GHOA were older than those with RCD (69.8 ± 12.2 vs 57.1 ± 15.1; p = 0.0001). Women represented 54% of cases of primary GHOA, and their presentation age was older than men (72.9 ± 11.2 vs 66.1 ± 12.4; p = 0.0005). Primary GHOA patients had a mean BMI of 31.0 ± 6.3, 48.7% had hyperlipidemia and 57.2% had hypertension. 24.3% were treated surgically within 2 years of follow-up. GHOA is a significant cause of shoulder pain in older age groups, and the majority of these patients have primary (idiopathic) GHOA. Primary GHOA affects dominant and non-dominant arms at similar rates, suggesting that anatomical and/or systemic factors are more important than overuse in GHOA pathogenesis. Given the prominence of GHOA in older age groups, changes in population demographics, and limitations of non-operative treatment, continued increases in shoulder replacement surgery are likely. Efforts to further understand GHOA pathogenesis and develop new, more effective therapies are advocated.

Dynamic kinematics of the glenohumeral joint in shoulders with rotator cuff tears

Background

No clear trend has emerged from the literature regarding three-dimensional (3D) translations of the humerus relative to the scapula in shoulders with rotator cuff tears (RCTs). The purpose of this study was to evaluate the kinematics of RCT shoulders using 3D-to-two-dimensional (2D) model-to-image registration techniques.

Methods

Dynamic glenohumeral kinematics during scapular plane abduction and axial rotation were analyzed in 11 RCT patients and 10 healthy control subjects. We measured the 3D kinematic parameters of glenohumeral joints using X-ray images and CT-derived digitally reconstructed radiographs.

Results

For scapular plane abduction, the humeral head center was positioned significantly more medially in shoulders with RCTs than in controls at 135° of humeral abduction (p = 0.02; RCTs versus controls: − 0.9 ± 1.6 versus 0.3 ± 1.3 mm). There was no significant difference in the superior/inferior translation of the humeral head center (p = 0.99). For axial rotation in adducted position, the humeral head center was positioned significantly more anteriorly in shoulders with RCTs than in controls at − 30° of glenohumeral external rotation (p < 0.0001; RCTs versus controls: 3.0 ± 1.7 versus 0.3 ± 1.5 mm).

Conclusions

This study revealed the kinematics of shoulders with large to massive full-thickness RCTs: the humeral head center showed a medial shift at the late phase of scapular plane full abduction, and an anterior shift at the internal rotation position during full axial rotation. The kinematic data in this study, which describe the patterns of movement of shoulders with large to massive full-thickness RCTs, provide valuable information for future studies investigating glenohumeral translations in other pathological conditions of the shoulder. For clinical relevance, quantitative assessment of the dynamic kinematics of shoulders with RCTs might be a therapeutic indicator for achieving functional restoration.

Validation of single-plane fluoroscopy and 2D/3D shape-matching for quantifying shoulder complex kinematics

Fluoroscopy and 2D/3D shape-matching has emerged as the standard for non-invasively quantifying kinematics. However, its accuracy has not been well established for the shoulder complex when using single-plane fluoroscopy. The purpose of this study was to determine the accuracy of single-plane fluoroscopy and 2D/3D shape-matching for quantifying full shoulder complex kinematics. Tantalum markers were implanted into the clavicle, humerus, and scapula of four cadaveric shoulders. Biplane radiographs were obtained with the shoulder in five humerothoracic elevation positions (arm at the side, 30°, 60°, 90°, maximum). Images from both systems were used to perform marker tracking, while only those images acquired with the primary fluoroscopy system were used to perform 2D/3D shape-matching. Kinematics errors due to shape-matching were calculated as the difference between marker tracking and 2D/3D shape-matching and expressed as root mean square (RMS) error, bias, and precision. Overall RMS errors for the glenohumeral joint ranged from 0.7 to 3.3° and 1.2 to 4.2 mm, while errors for the acromioclavicular joint ranged from 1.7 to 3.4°. Errors associated with shape-matching individual bones ranged from 1.2 to 3.2° for the humerus, 0.5 to 1.6° for the scapula, and 0.4 to 3.7° for the clavicle. The results of the study demonstrate that single-plane fluoroscopy and 2D/3D shape-matching can accurately quantify full shoulder complex kinematics in static positions.

Examination of concomitant glenohumeral pathologies in patients treated arthroscopically for calcific tendinitis of the shoulder and implications for routine diagnostic joint exploration

Background

Glenohumeral exploration is routinely performed during arthroscopic removal of rotator cuff calcifications in patients with calcific tendinitis of the shoulder (CTS). However, evidence on the prevalence of intraarticular co-pathologies is lacking and the benefit of glenohumeral exploration remains elusive. The aim of the present study was to assess and quantify intraoperative pathologies during arthroscopic removal of rotator cuff calcifications in order to determine whether standardized diagnostic glenohumeral exploration appears justified in CTS patients.

Methods

One hundred forty five patients undergoing arthroscopic removal of calcific depots (CD) that failed conservative treatment were included in a retrospective cohort study. Radiographic parameters including number/localization of calcifications and acromial types, intraoperative arthroscopic findings such as configuration of glenohumeral ligaments, articular cartilage injuries, and characteristics of calcifications and sonographic parameters (characteristics/localization of calcification) were recorded.

Results

One hundred forty five patients were analyzed. All CDs were removed by elimination with a blunt hook probe via “squeeze-and-stir-technique” assessed postoperatively via conventional X-rays. Neither subacromial decompression nor refixation of the rotator cuff were performed in any patient. Prevalence of glenohumeral co-pathologies, such as partial tears of the proximal biceps tendon (2.1%), superior labral tears from anterior to posterior (SLAP) lesions (1.4%), and/or partial rotator cuff tears (0.7%) was low. Most frequently, glenohumeral articular cartilage was either entirely intact (ICRS grade 0 (humeral head/glenoid): 46%/48%) or showed very mild degenerative changes (ICRS grade 1: 30%/26%). Two patients (1.3%) required intraarticular surgical treatment due to a SLAP lesion type III (n = 1) and an intraarticular rupture of CD (n = 1).

Conclusions

Routine diagnostic glenohumeral exploration does not appear beneficial in arthroscopic treatment of CTS due to the low prevalence of intraarticular pathologies which most frequently do not require surgical treatment. Exploration of the glenohumeral joint in arthroscopic removal of CD should only be performed in case of founded suspicion of relevant concomitant intraarticular pathologies.

In vivo kinematic analysis of the glenohumeral joint during dynamic full axial rotation and scapular plane full abduction in healthy shoulders

PURPOSE

The purpose of this study was to evaluate the kinematics of healthy shoulders during dynamic full axial rotation and scapular plane full abduction using three-dimensional (3D)-to-two-dimensional (2D) model-to-image registration techniques.

METHODS

Dynamic glenohumeral kinematics during axial rotation and scapular plane abduction were analysed in 10 healthy participants. Continuous radiographic images of axial rotation and scapular plane abduction were taken using a flat panel radiographic detector. The participants received a computed tomography scan to generate virtual digitally reconstructed radiographs. The density-based digitally reconstructed radiographs were then compared with the serial radiographic images acquired using image correlations. These 3D-to-2D model-to-image registration techniques determined the 3D positions and orientations of the humerus and scapula during dynamic full axial rotation and scapular plane full abduction.

RESULTS

The humeral head centre translated an average of 2.5 ± 3.1 mm posteriorly, and 1.4 ± 1.0 mm superiorly in the early phase, then an average of 2.0 ± 0.8 mm inferiorly in the late phase during external rotation motion. The glenohumeral external rotation angle had a significant effect on the anterior/posterior (A/P) and superior/inferior (S/I) translation of the humeral head centre (both p < 0.05). 33.6 ± 15.6° of glenohumeral external rotation occurred during scapular plane abduction. The humeral head centre translated an average of 0.6 ± 0.9 mm superiorly in the early phase, then 1.7 ± 2.6 mm inferiorly in the late phase, and translated an average of 0.4 ± 0.5 mm medially in the early phase, then 1.6 ± 1.0 mm laterally in the late phase during scapular plane abduction. The humeral abduction angle had a significant effect on the S/I and lateral/medial (L/M) translation of the humeral head centre (both p < 0.05).

CONCLUSION

This study investigated 3D translations of the humerus relative to the scapula: during scapular plane full abduction, the humerus rotated 33.6° externally relative to the scapula, and during external rotation motion in the adducted position, the humeral head centre translated an average of 2.5 mm posteriorly. Kinematic data will provide important insights into evaluating the kinematics of pathological shoulders. For clinical relevance, quantitative assessment of dynamic healthy shoulder kinematics might be a physiological indicator for the assessment of pathological shoulders.

A systematic comparison of the closed shoulder reduction techniques

PURPOSE

To identify the optimal technique for closed reduction for shoulder instability, based on success rates, reduction time, complication risks, and pain level.

METHODS

A PubMed and EMBASE query was performed, screening all relevant literature of closed reduction techniques mentioning the success rate written in English, Dutch, German, and Arabic. Studies with a fracture dislocation or lacking information on success rates for closed reduction techniques were excluded. We used the modified Coleman Methodology Score (CMS) to assess the quality of included studies and excluded studies with a poor methodological quality (CMS < 50). Finally, a meta-analysis was performed on the data from all studies combined.

RESULTS

2099 studies were screened for their title and abstract, of which 217 studies were screened full-text and finally 13 studies were included. These studies included 9 randomized controlled trials, 2 retrospective comparative studies, and 2 prospective non-randomized comparative studies. A combined analysis revealed that the scapular manipulation is the most successful (97%), fastest (1.75 min), and least painful reduction technique (VAS 1,47); the "Fast, Reliable, and Safe" (FARES) method also scores high in terms of successful reduction (92%), reduction time (2.24 min), and intra-reduction pain (VAS 1.59); the traction-countertraction technique is highly successful (95%), but slower (6.05 min) and more painful (VAS 4.75).

CONCLUSION

For closed reduction of anterior shoulder dislocations, the combined data from the selected studies indicate that scapular manipulation is the most successful and fastest technique, with the shortest mean hospital stay and least pain during reduction. The FARES method seems the best alternative.

Prevention and management of post-instability glenohumeral arthropathy

Post-instability arthropathy may commonly develop in high-risk patients with a history of recurrent glenohumeral instability, both with and without surgical stabilization. Classically related to anterior shoulder instability, the incidence and rates of arthritic progression may vary widely. Radiographic arthritic changes may be present in up to two-thirds of patients after primary Bankart repair and 30% after Latarjet procedure, with increasing rates associated with recurrent dislocation history, prominent implant position, non-anatomic reconstruction, and/or lateralized bone graft placement. However, the presence radiographic arthrosis does not predict poor patient-reported function. After exhausting conservative measures, both joint-preserving and arthroplasty surgical options may be considered depending on a combination of patient-specific and anatomic factors. Arthroscopic procedures are optimally indicated for individuals with focal disease and may yield superior symptomatic relief when combined with treatment of combined shoulder pathology. For more advanced secondary arthropathy, total shoulder arthroplasty remains the most reliable option, although the clinical outcomes, wear characteristics, and implant survivorship remains a concern among active, young patients.

3D-CT of the shoulder in patients with glenohumeral instability

OBJECTIVE

To determine whether 3D-MR osseous reformats of the shoulder are equivalent to 3D-CT osseous reformats in patients with glenohumeral instability.

MATERIALS AND METHODS

Patients with glenohumeral instability, who were to be imaged with both CT and MRI, were prospectively selected. CT and MR were performed within 24 h of one another on 12 shoulders. Each MR study included an axial 3D isotropic VIBE sequence. The image data from the isotropic VIBE sequence were post-processed using subtraction and 3D software. CT data were post-processed using 3D software. The following measurements were obtained for both 3D-CT and 3D-MR post-processed images: height and width of the humeral head and glenoid, Hill-Sachs size and percent humeral head loss (if present), size of glenoid bone loss and percent glenoid bone loss (if present). Paired t-tests and two one-sided tests for equivalence were used to assess the differences between imaging modalities and equivalence.

RESULTS

The measurement differences from the 3D-CT and 3D-MR post-processed images were not statistically significant. The measurement differences for humeral height, glenoid height and glenoid width were borderline statistically significant; however, using any adjustment for multiple comparisons, this failed to be significant. Using an equivalence margin of 1 mm for measurements and 1.5% for percent bone loss, the 3D-MR and 3D-CT post-processed images were equivalent.

CONCLUSION

Three-dimensional-MR osseous models of the shoulder using a 3D isotropic VIBE sequence were equivalent to 3D-CT osseous models, and the differences between modalities were not statistically significant.

Isokinetic clinical assessment of rotator cuff strength in subacromial shoulder impingement

BACKGROUND

Current conservative management of subacromial shoulder impingement (SSI) includes generic strengthening exercises, especially for internal (IR) and external (ER) shoulder rotators. However, there is no evidence that the strength or the ratio of strength between these muscle groups is different between those with SSI (cases) and an asymptomatic population (controls).

OBJECTIVE

To identify if isokinetic rotator cuff strength or the ratio of strength is significantly different between cases and controls.

STUDY DESIGN

Case Control Study.

METHOD

Fifty one cases with SSI and 51 asymptomatic controls matched for age, gender, hand dominance and physical activity level completed isokinetic peak torque glenohumeral IR and ER testing. Within the SSI group, 31 dominant limbs were symptomatic and 20 non-dominant limbs were symptomatic. IR and ER were measured separately using continuous reciprocal concentric (con) and eccentric (ecc) contraction cycles at a speed of 60 degrees per second and again at 120 degrees per second. Values of peak torque (PT), relative peak torque (RPT) and ratios were compared using independent t-tests between the SSI and asymptomatic groups.

RESULTS

Significant strength differences between the two groups were present only when the symptomatic SSI shoulder was the dominant shoulder (con ER PT at 60°/second, ecc ER PT at 120°/second, ecc ER RPT at 120°/second and ecc IR PT at 60°/second and 120°/second).

CONCLUSIONS

Changes in rotator cuff strength in SSI may be related to limb dominance, which may have implications for strengthening regimes.

LEVEL OF EVIDENCE

Level 3a.

What can the Radiologist do to Help the Surgeon Manage Shoulder Instability?

Imaging of the shoulder forms an important adjunct in clinical decision making in patients with shoulder instability. The typical lesions related with classic anterior and anteroinferior shoulder dislocation are an anteroinferior labral avulsion with or without bony fragment of bone loss – a (bony) Bankart lesion – and a posterolateral humeral head impaction fracture – the Hill-Sachs lesions. These are relatively straightforward to identify on imaging, although normal variants of the inferior labrum and variants of labral damage may cause confusion. Other capsuloligamentous lesions, often associated with less typical types of instability, are much more difficult to identify correctly on imaging, as they occur in the anterosuperior part of the glenohumeral joint with its many normal variants or because they result in more subtle, and therefore easily overlooked, changes in morphology or signal intensity. This paper aims at describing the appearance of the normal and pathologic glenohumeral joint related to shoulder instability. Ample reference will be given as to why identification of abnormalities, whether normal or pathologic, is important to the surgeon facing a treatment decision.

A systematic and technical guide on how to reduce a shoulder dislocation

Objectives

Our objective is to provide a systematic and technical guide on how to reduce a shoulder dislocation, based on techniques that have been described in literature for patients with anterior and posterior shoulder instability.

Materials and methods

A PubMed and EMBASE query was performed, screening all relevant literature on the closed reduction techniques. Studies regarding open reduction techniques and studies with fracture dislocations were excluded.

Results

In this study we give an overview of 23 different techniques for closed reduction and 17 modifications of these techniques.

Discussion

In this review article we present a complete overview of the techniques, that have been described in the literature for closed reduction for shoulder dislocations. This manuscript can be regarded as a clinical guide how to perform a closed reduction maneuver, including several technical tips and tricks to optimize the success rate and to avoid complications.

Conclusion

There are 23 different reduction techniques with 17 modifications of these techniques. Knowledge of the different techniques is highly important for a good reduction.

Subject-specific musculoskeletal modeling in the evaluation of shoulder muscle and joint function

Upper limb muscle force estimation using Hill-type muscle models depends on musculotendon parameter values, which cannot be readily measured non-invasively. Generic and scaled-generic parameters may be quickly and easily employed, but these approaches do not account for an individual subject's joint torque capacity. The objective of the present study was to develop a subject-specific experimental testing and modeling framework to evaluate shoulder muscle and joint function during activities of daily living, and to assess the capacity of generic and scaled-generic musculotendon parameters to predict muscle and joint function. Three-dimensional musculoskeletal models of the shoulders of 6 healthy subjects were developed to calculate muscle and glenohumeral joint loading during abduction, flexion, horizontal flexion, nose touching and reaching using subject-specific, scaled-generic and generic musculotendon parameters. Muscle and glenohumeral joint forces calculated using generic and scaled-generic models were significantly different to those of subject-specific models (p<0.05), and task dependent; however, scaled-generic model calculations of shoulder glenohumeral joint force demonstrated better agreement with those of subject-specific models during abduction and flexion. Muscles in generic musculoskeletal models operated further from the plateau of their force-length curves than those of scaled-generic and subject-specific models, while muscles in subject-specific models operated over a wider region of their force length curves than those of the generic or scaled-generic models, reflecting diversity of subject shoulder strength. The findings of this study suggest that generic and scaled-generic musculotendon parameters may not provide sufficient accuracy in prediction of shoulder muscle and joint loading when compared to models that employ subject-specific parameter-estimation approaches.

Isolated glenohumeral range of motion, excluding side-to-side difference in humeral retroversion, in asymptomatic high-school baseball players

PURPOSE

Glenohumeral range of motion is correlated with shoulder capsular condition and is thus considered to be predictive of shoulder pathology. However, in throwing athletes, a side-to-side difference in humeral retroversion makes it difficult to evaluate capsular condition on the basis of glenohumeral range of motion measured by using the conventional technique. The purpose of this study was to measure isolated glenohumeral rotation, excluding side-to-side differences in humeral retroversion, in asymptomatic high-school baseball players.

METHODS

A total of 195 high-school baseball players (52 pitchers and 143 position players; median age, 16 years) and 20 high-school non-throwing athletes (median age, 16 years) without any shoulder symptoms were enroled in this study. Glenohumeral external and internal rotations were measured by using both a conventional technique and our ultrasound-assisted technique. This technique, neutral rotation, was standardized on the basis of the ultrasonographically visualized location of the bicipital groove to exclude side-to-side differences in humeral retroversion from the calculated rotation angle. Intra- and inter-observer agreements of rotational measurements were evaluated by using intra-class correlation coefficients (ICCs).

RESULTS

Isolated glenohumeral rotation measurements, excluding side-to-side differences in humeral retroversion, demonstrated excellent intra-observer (ICC > 0.89) and inter-observer (ICC > 0.78) agreements. Isolated glenohumeral internal rotation was significantly less in the dominant shoulder than in the non-dominant shoulder in asymptomatic baseball players (P < 0.001). Isolated glenohumeral external rotation in baseball players was significantly greater than in non-throwing athletes (P < 0.05). In the baseball players, humeral torsion in the dominant shoulder was significantly greater than that in the non-dominant shoulder (P < 0.001), indicating that the retroversion angle was greater in dominant shoulders than in non-dominant shoulders.

CONCLUSIONS

Isolated glenohumeral external and internal rotations can be measured with high intra- and inter-observer reliability with the exclusion of side-to-side differences in humeral retroversion. Capsular and muscular changes in the throwing shoulder may be better evaluated by using our ultrasound-assisted technique.

LEVEL OF EVIDENCE

Cross-sectional study, Level III.

Rotator cuff tears after total shoulder arthroplasty in primary osteoarthritis: A systematic review

Rotator cuff tears have been reported to be uncommon following total shoulder arthroplasty (TSA). Postoperative rotator cuff tears can lead to pain, proximal humeral migration, and glenoid component loosening. The purpose of this paper was to evaluate the incidence of post-TSA rotator cuff tears or dysfunction in osteoarthritic patients. A systematic review of multiple databases was performed using preferred reporting items for systematic reviews and meta-analyses guidelines. Levels I-IV evidence clinical studies of patients with primary osteoarthritis with a minimum 2-year follow-up were included. Fifteen studies with 1259 patients (1338 shoulders) were selected. Student's t-tests were used with a significant alpha value of 0.05. All patients demonstrated significant improvements in motion and validated clinical outcome scores (P < 0.001). Radiographic humeral head migration was the most commonly reported data point for extrapolation of rotator cuff integrity. After 6.6 ± 3.1 years, 29.9 ± 20.7% of shoulders demonstrated superior humeral head migration and 17.9 ± 14.3% migrated a distance more than 25% of the head. This was associated with an 11.3 ± 7.9% incidence of postoperative superior cuff tears. The incidence of radiographic anterior humeral head migration was 11.9 ± 15.9%, corresponding to a 3.0 ± 13.6% rate of subscapularis tears. We found an overall 1.2 ± 4.5% rate of reoperation for cuff injury. Nearly all studies reported indirect markers of rotator cuff dysfunction, such as radiographic humeral head migration and clinical exam findings. This systematic review suggests that rotator cuff dysfunction following TSA may be more common than previously reported. IV, systematic review of Levels I-IV studies.

The arthritic glenoid: anatomy and arthroplasty designs

The number of shoulder arthroplasty procedures has increased dramatically in recent years, with the primary indication being osteoarthritis (OA). Thus, morphology and subchondral bone changes associated with OA may be important factors to consider when choosing a replacement component. For surgical treatment, many implant options exist and survivability is often dependent on patient age, activity level, and progression of OA. In the placement of these replacement components, patient-specific guides now exist to improve component positioning, with the goal to improve long-term survivability by ensuring that intra-operative placement meets component design.

Anatomy of the capsulolabral complex and rotator interval related to glenohumeral instability

The glenohumeral joint with instability is a common diagnosis that often requires surgery. The aim of this review was to present an overview of the anatomy of the glenohumeral joint with emphasis on instability based on the current literature and to describe the detailed anatomy and anatomical variants of the glenohumeral joint associated with anterior and posterior shoulder instability. A review was performed using PubMed/MEDLINE using key words: Search terms were "glenohumeral", "shoulder instability", "cadaver", "rotator interval", "anatomy", and "anatomical study". During the last decade, the interest in both arthroscopic repair techniques and surgical anatomy of the glenohumeral ligament (superior, middle, and inferior), labrum, and rotator interval has increased. Understanding of the rotator interval and attachment of the inferior glenohumeral ligament on the glenoid or humeral head have evolved significantly. The knowledge of the detailed anatomy and anatomical variations is essential for the surgeon in order to understand the pathology, make a correct diagnosis of instability, and select proper treatment options. Proper understanding of anatomical variants can help us avoid misdiagnosis. Level of evidence V.

The Bristow-Latarjet procedure, a historical note on a technique in comeback

The Bristow-Latarjet procedure is a well-known surgical technique designed to treat shoulder instability. In this procedure, the coracoid process is transferred to the glenoid rim, to serve as augmentation of an associated bony defect. Because long-term results following a soft tissue procedure (Bankart repair) reveal that up to 21 and 33 % of the patients might experience recurrent instability and with the advent of the arthroscopic coracoid transfer, there is renewed interest in this procedure to treat shoulder instability. The aim of this study is to provide a historical overview, with emphasis on the original inventors Bristow and Latarjet, the complications and following modifications regarding the surgical approach, the coracoid transfer and the arthroscopic technique. Level of evidence V.

The stiff shoulder; A case study

Clinicians working in outpatient departments and advanced practitioner clinics frequently encounter patients presenting with multidirectional stiffness of the glenohumeral joint. This case report describes the assessment and treatment of a patient presenting with glenohumeral joint stiffness and describes the possible differential diagnoses. The evidence base used to inform the decision-making process is presented and the use of radiology that helped to ultimately establish the diagnosis is discussed. The clinical reasoning process of applying knowledge and experience to identify patient problems and to make appropriate decisions that result in positive patient outcomes is discussed. The case report highlights the importance of early diagnosis.

Collecting shoulder kinematics with electromagnetic tracking systems and digital inclinometers: A review

The shoulder complex presents unique challenges for measuring motion as the scapula, unlike any other bony segment in the body, glides and rotates underneath layers of soft tissue and skin. The ability for clinicians and researchers to collect meaningful kinematic data is dependent on the reliability and validity of the instrumentation utilized. The aim of this study was to review the relevant literature pertaining to the reliability and validity of electromagnetic tracking systems (ETS) and digital inclinometers for assessing shoulder complex motion. Advances in technology have led to the development of biomechanical instrumentation, like ETS, that allow for the collection of three-dimensional kinematic data. The existing evidence has demonstrated that ETS are reliable and valid instruments for collecting static and dynamic kinematic data of the shoulder complex. Similarly, digital inclinometers have become increasingly popular among clinicians due to their cost effectiveness and practical use in the clinical setting. The existing evidence supports the use of digital inclinometers for the collection of shoulder complex kinematics as these instruments have been demonstrated to yield acceptable reliability and validity. While digital inclinometers pose a disadvantage to ETS regarding accuracy, precision, and are limited to two-dimensional and static measurements, this instrument provides clinically meaningful data that allow clinicians and researchers the ability to measure, monitor, and compare shoulder complex kinematics.