Detecting and dissecting signaling crosstalk via the multilayer network integration of signaling and regulatory interactions.

The versatility of cellular response arises from the communication, or crosstalk, of signaling pathways in a complex network of signaling and transcriptional regulatory interactions. Understanding the various mechanisms underlying crosstalk on a global scale requires untargeted computational approaches. We present a network-based statistical approach, MuXTalk, that uses high-dimensional edges called multilinks to model the unique ways in which signaling and regulatory interactions can interface. We demonstrate that the signaling-regulatory interface is located primarily in the intermediary region between signaling pathways where crosstalk occurs, and that multilinks can differentiate between distinct signaling-transcriptional mechanisms. Using statistically over-represented multilinks as proxies of crosstalk, we infer crosstalk among 60 signaling pathways, expanding currently available crosstalk databases by more than five-fold. MuXTalk surpasses existing methods in terms of model performance metrics, identifies additions to manual curation efforts, and pinpoints potential mediators of crosstalk. Moreover, it accommodates the inherent context-dependence of crosstalk, allowing future applications to cell type- and disease-specific crosstalk.

Editorial Commentary: Acute Treatment Including Cerclage Result in Best Surgical Outcomes for High-Grade Acromioclavicular Joint Separations.

Despite years of research, optimal treatment of acute high-grade acromioclavicular joint (ACJ) separations remains controversial. ACJ separations occur in a "multiplanar" fashion and identification of horizonal plane instability is paramount to differentiate between high-grade versus low-grade injuries. As surgeons, we treat a self-selected group of patients referred for surgery, and our physiotherapy colleagues may rehabilitate many patients with both "low-grade" and "high-grade" separations who compensate. Of importance, ACJ separations stabilized <3 weeks after injury have the best chance of healing in a close-to anatomic position. The addition of the ACJ cerclage augmentation improves horizontal plane stability while the soft tissues heal and likely improves outcome.

The relationship between preoperative Goutallier stage and retear rates following posterosuperior rotator cuff repair: a systematic review.

BACKGROUND: An association between higher preoperative Goutallier stage and higher retear rates following primary rotator cuff repairs has been previously reported. However, there are few reviews which have described clear retear rates for each repaired tendon classified according to preoperative Goutallier stage. The purpose of this study was therefore to systematically review the literature on the relationship between preoperative Goutallier stage and retear rates and provide predictable retear rates following primary repair of posterosuperior rotator cuff tears. METHODS: A systematic literature review was performed in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and checklist utilizing PubMed, MEDLINE, and Cochrane Library. English-language studies of Level I through IV evidence examining the clinical results of primarily repaired posterosuperior rotator cuff tears as a function of Goutallier stage using magnetic resonance imaging were included. The primary outcome of interest was retear rates according to preoperative Goutallier stage. As a secondary outcome, rotator cuff tears were divided into 2 subgroups (Goutallier stage 0-2 and 3-4) and retear rates were assessed between the 2 subgroups. A random effects model with binomial within-study variance was used for both outcomes. RESULTS: Nine studies (687 shoulders) satisfied all inclusion criteria and reported sufficient data for statistical analysis. In the supraspinatus muscle group, rotator cuff muscles with preoperative Goutallier stages of 0, 1, and 2 had retear rates of 19.1%, 27.8%, and 33.5%, respectively, with no significant differences between each category. In contrast, when preoperative Goutallier stage of 3 and 4 existed, significant differences compared to Goutallier 0, 1, and 2 were observed with a retear rate of 74.1% and 78.5%, respectively. In the infraspinatus muscle group, the retear rates following rotator cuff repairs were 20.0%, 32.1%, and 35.1% in Goutallier 0, 1, and 2, respectively, with no significant differences between each category. In Goutallier 3 and 4, the rate was 76.6% and 100.0%, respectively, with significant differences compared to Goutallier 0, 1, and 2. CONCLUSION: The results of this study have clearly demonstrated that retear rates following surgical repair of the rotator cuff increased in proportion to the preoperative Goutallier stage in both the supraspinatus and infraspinatus muscles.

Graft Healing Is More Important Than Graft Technique: Superior Capsular Reconstruction Versus Bridging Grafts-A Prospective Randomized Controlled Trial.

PURPOSE: To compare superior capsular reconstruction (SCR) versus bridging graft (BG) for massive irreparable rotator cuff tears (RCTs). METHODS: A prospective double-blind randomized study was conducted to compare SCR versus BG for massive irreparable RCTs. Fifty patients (mean age: 60.2 ± 6.0 years) with chronic tears (mean duration of symptoms: 5 ± 5.2 years) were intraoperatively randomized following partial repair to SCR or BG using human dermal allograft. All patients underwent standardized rehabilitation and were followed at 3, 6, 12, and 24 months clinically and radiographically. Magnetic resonance imaging were obtained at 12 months to determine graft integrity. RESULTS: At 2 years, 46 patients were available for follow-up. Mean American Shoulder and Elbow Surgeons (ASES), Western Ontario Rotator Cuff (WORC), and Quick Disabilities of the Arm, Shoulder and Hand scores were 74.8 ± 23.9, 66.0 ± 28.3, and 24.7 ± 26.1 for the SCR group, and 77.9 ± 19.9, 69.5 ± 24.5, and 25.0 ± 19.1 for the BG group, respectively, with no significant difference between groups. Magnetic resonance imaging demonstrated 18 of 24 (75%) in the SCR group and 14 of 22 (64%) in the BG group were intact at 12 months (P = .53). Patients with intact grafts compared with those with retorn grafts, whether SCR or BG, had greater ASES and WORC scores at 24 months (ASES 81.0 ± 18.7 vs 65.7 ± 24.4, P = .021 and WORC 72.3 ± 24.6 vs 53.7 ± 26.7, P = .04) and greater acromiohumeral intervals on radiographs at all follow-up time points. CONCLUSIONS: When performing arthroscopic reconstruction using human dermal allograft for an irreparable RCT, whether the proximal edge of the graft is attached on the glenoid bone or to the torn tendon does not significantly change short-term clinical and radiographic outcomes. LEVEL OF EVIDENCE: I, therapeutic.

Editorial Commentary: Causes of Failure After Arthroscopic Rotator Cuff Repair.

Causes of failure after arthroscopic rotator cuff repair include patient factors, tear factors, and surgical factors. Failure may occur at the suture-tendon interface, the bone-tendon interface, or the bone-anchor interface. Low bone mineral density (BMD) in the greater tuberosity has been reported as a prognostic factor for recurrent tears following rotator cuff repair, and although most studies suggest the tendon-to-suture interface as the "weakest link," patients with low BMD may have lower suture anchor pull-out strength. A potential alternative cause of failure is the suture cutting through the greater tuberosity bone in patients with low BMD. Knotless suture bridge constructs or single-row constructs may be more susceptible to a suture cutting through the bone. The knotted suture bridge technique, wherein the medial mattress sutures are tied, may to some extent "shield" against complete cut-through. When bone quality appears poor, a common response is to change the type of anchor, size of anchor, or the location of the anchor. Other factors, such as bone preparation, suture type, suture tensioning, and anchor type (e.g., internal vs external locking), may all potentially affect suture cutting through weak bone.

Platelet-Rich Plasma in Patients With Partial-Thickness Rotator Cuff Tears or Tendinopathy Leads to Significantly Improved Short-Term Pain Relief and Function Compared With Corticosteroid Injection: A Double-Blind Randomized Controlled Trial.

PURPOSE: To perform a randomized controlled trial comparing platelet-rich plasma (PRP) with standard corticosteroid (CS) injection in providing pain relief and improved function in patients with rotator cuff tendinopathy and partial-thickness rotator cuff tears (PTRCTs). METHODS: This double-blind randomized controlled trial enrolled patients with ultrasound-proven or magnetic resonance imaging-proven PTRCTs who received either an ultrasound-guided PRP or CS injection. Patients completed patient-reported outcome assessments at baseline and at 6 weeks, 3 months, and 12 months after injection. The primary outcome was improvement in the visual analog scale (VAS) score for pain. Secondary outcomes included changes in American Shoulder and Elbow Surgeons (ASES) and Western Ontario Rotator Cuff Index (WORC) scores. Treatment failure was defined as subsequent injection, consent to undergo surgery, or operative intervention. RESULTS: We followed up 99 patients (47 in the PRP group and 52 in the CS group) until 12 months after injection. There were no differences in baseline patient demographic characteristics including age, sex, or duration of symptoms. Despite randomization, patients in the PRP group had worse baseline VAS (46.0 vs 34.7, P = .01), ASES (53.9 vs 61.8, P = .02), and WORC (42.2 vs 49.5, P = .03) scores. At 3 months after injection, the PRP group had superior improvement in VAS (-13.6 vs 0.4, P = .03), ASES (13.0 vs 2.9, P = .02), and WORC (16.8 vs 5.8, P = .03) scores. There were no differences in patient-reported outcomes at 6 weeks or 12 months. There was no difference in the rate of failure (P = .31) or conversion to surgery (P = .83) between groups. CONCLUSIONS: Patients with PTRCTs or tendinopathy experienced clinical improvement in pain and patient-reported outcome scores after both ultrasound-guided CS and PRP injections. Patients who received PRP obtained superior improvement in pain and function at short-term follow-up (3 months). There was no sustained benefit of PRP over CS at longer-term follow-up (12 months). LEVEL OF EVIDENCE: Level I, randomized controlled trial.

Evaluation and Management of Glenohumeral Instability With Associated Bone Loss: An Expert Consensus Statement Using the Modified Delphi Technique.

PURPOSE: To establish an international expert consensus, using the modified Delphi technique, on the evaluation and management of glenohumeral instability with associated bone loss. METHODS: A working group of 6 individuals generated a list of statements related to history and physical examination, imaging and specialized diagnostic tests, bone loss quantification and classification, treatment outcomes and complications, and rehabilitation for the management of glenohumeral instability associated with bone loss to form the basis of an initial survey for rating by a group of experts. The expert group (composed of 22 high-volume glenohumeral instability experts) was surveyed on 3 occasions to establish a consensus on the statements. Items with over 70% agreement and less than 10% disagreement achieved consensus. RESULTS: After a total of 3 rounds, 31 statements achieved consensus. Eighty-six percent of the experts agreed that a history of multiple dislocations and failed soft-tissue surgery should raise suspicion about the possibility of an associated bone deficit. Ninety-five percent of the experts agreed that 3-dimensional (3D) computed tomography (CT) is the most accurate diagnostic method to evaluate and quantify bone loss. Eighty-six percent of the experts agreed that any of the available methods to measure glenoid bone deficiency is adequate; however, 91% of the experts thought that an en face view of the glenoid using 3D CT provides the most accurate method. Ninety-five percent of the experts agreed that Hill-Sachs lesions are poorly quantified and classified by current imaging systems. Ninety percent of the experts agreed that in cases with a glenoid bone deficit greater than 20%, glenoid bone graft reconstruction should be performed and any of the available options is valid. There was no consensus among experts on how Hill-Sachs injuries should be managed or on how postoperative rehabilitation should be carried out. CONCLUSIONS: The essential statements on which the experts reached consensus included the following: A history of multiple dislocations and failed soft-tissue surgery should make surgeons consider the possibility of an associated bone deficit. Three-dimensional CT is the most accurate diagnostic method to evaluate and quantify bone loss. Although any of the available methods to measure glenoid bone deficiency is adequate, an en face view of the glenoid using 3D CT provides the most accurate method. Hill-Sachs lesions are poorly quantified and classified by current imaging systems. Finally, in cases with a glenoid bone deficit greater than 20%, glenoid bone graft reconstruction should be performed. LEVEL OF EVIDENCE: Level V, consensus statement.

Determining the rate of full-thickness progression in partial-thickness rotator cuff tears: a systematic review.

BACKGROUND: Partial-thickness rotator cuff tears are likely at least as common as full-thickness rotator cuff tears, and it is critical for surgeons to have knowledge of the tear progression rate of partial-thickness rotator cuff tears when determining surgical or nonsurgical treatment. However, a systematic review investigating the rate of tear progression of partial-thickness rotator cuff tears has not been performed. Therefore, the purpose of this study was to systematically review the literature and determine the rate of full-thickness progression in nonoperatively treated partial-thickness rotator cuff tears. METHODS: A systematic review of the literature was performed following the PRISMA guidelines and checklist using the PubMed, MEDLINE, and Cochrane Library databases. English-language studies of Level I through IV evidence examining partial-thickness rotator cuff tears with description of the change in tear size were included. Studies using imaging modalities other than magnetic resonance imaging (MRI) or ultrasonography (US) for serial imaging and studies without description of the number of tears that progressed to full-thickness tears were excluded. The primary outcome was to determine the per-month progression rate from a partial-thickness tear to a full-thickness tear confirmed on either MRI or US. The progression rates, which were divided into 3 groups-symptomatic, asymptomatic and combined (asymptomatic + symptomatic)-were calculated using a random effects model with binomial within-study variance. RESULTS: Four studies were included, and 257 tears were analyzed statistically for tear progression. The average follow-up was 34 months (standard deviation, 19 months). The overall rate of progression to a full-thickness tear was 0.26% per month (95% confidence interval [CI], 0.15%-0.36% per month). In the symptomatic and asymptomatic groups, the rates were 0.22% per month (95% CI, 0.09%-0.34% per month) and 0.32% per month (95% CI, 0.15%-0.49% per month), respectively, which showed no significant difference (P =.341). CONCLUSIONS: This study demonstrated that partial-thickness tears progress to full-thickness tears over time but at a relatively low rate at short- to intermediate-term follow-up. There was no significant difference in the per-month rates of full-thickness progression between symptomatic and asymptomatic tears.

Editorial Commentary: Working Around the Coracoid-The Lighthouse to the Shoulder.

Working around the coracoid has now become commonplace in arthroscopic shoulder surgery. No longer is there a safe side and a "suicide"; therefore, it is important to recognize the potential for neurovascular injury when surgery is performed about the coracoid. Although safe zones and distances are important, when more complex procedures are performed arthroscopically, direct visualization and identification of neurovascular structures is critical in avoiding iatrogenic injury.

Full-Thickness Rotator Cuff Tears: What Is the Rate of Tear Progression? A Systematic Review.

PURPOSE: To systematically review the literature and determine the rate of radiographic tear progression of nonoperatively treated full-thickness rotator cuff tears. METHODS: The PubMed, Embase, and Cochrane Library databases were systematically reviewed to identify all articles related to nonoperatively treated rotator cuff tears. English-language studies of Level I through IV evidence examining chronic, full-thickness rotator cuff tears in adults were included. Partial-thickness tears were excluded. Rotator cuff tears were analyzed according to the presence or absence of symptoms. The primary outcome was radiographic tear progression defined as an increase in tear size of 5 mm or greater on magnetic resonance imaging or ultrasound. RESULTS: Eight studies were included for statistical analysis, and 411 tears were analyzed for progression. No difference in the rate of tear progression was detected between the asymptomatic and symptomatic groups (40.6% at 46.8 months and 34.1% at 37.8 months, respectively; P = .65). Calculation of the number needed to treat showed that for an 8% retear rate at 2-year follow-up, approximately 7 patients with rotator cuff tears would have to undergo operative repair to prevent 1 tear from progressing radiographically. CONCLUSIONS: This study showed that with the data available, asymptomatic and symptomatic rotator cuff tears carry similar rates of tear progression over time. Most of these tears will not progress significantly over short- to intermediate-term follow-up. LEVEL OF EVIDENCE: Level IV, systematic review of Level I through IV evidence.

Mechanical and imaging evaluation of the effect of sutures on tendons: tape sutures are protective to suture pulling through tendon.

BACKGROUND: High-strength sutures, including #2 and tape-type, are popular when performing arthroscopic rotator cuff repair. Although the most common mechanism of anatomic failure of rotator cuff repair is suture pulling through tendon, the effect of sutures on the suture-tendon interface has rarely been investigated. We evaluated the effect of commercially available modern high-strength standard #2 and tape-type sutures on tendon. METHODS: Isolated sutures (FiberTape, #2 FiberWire [Arthrex Inc., Naples, FL, USA], Ultratape, and #2 Ultrabraid [Smith & Nephew, Andover, MA, USA]) and suture-tendon constructs using sheep infraspinatus tendons were evaluated using mechanical testing and imaging (microcomputed tomography) techniques. RESULTS: For the 4 suture-tendon constructs evaluated, maximum and residual displacements were all less than 3 mm. Whether evaluating isolated sutures or suture-tendon constructs, tape-type sutures had smaller displacements than standard #2 sutures when products from the same company were compared. On initial suture passing and after mechanical testing, hole volume was larger in constructs with tape-type rather than standard #2 sutures comparing within the same company. Collectively, constructs with larger hole volumes after mechanical testing had stiffer sutures. The percentage difference in hole volume was larger for standard #2 than tape-type sutures: FiberWire (43%), Ultrabraid (17%), FiberTape (11%), and Ultratape (9%). CONCLUSIONS: Tape-type sutures created larger final holes than standard #2 sutures from the same company. When initially passed through the tendon, tape-type sutures produced larger holes than standard #2 sutures; however, standard #2 sutures enlarged their initially smaller holes more and displaced more than tape-type sutures during cyclic loading, which suggests that tape-type sutures may be protective to suture pulling through tendon.

What happens to patients when we do not repair their cuff tears? Five-year rotator cuff quality-of-life index outcomes following nonoperative treatment of patients with full-thickness rotator cuff tears.

BACKGROUND: The purpose of this study was to examine 5-year outcomes in a prospective cohort of patients previously enrolled in a nonoperative rotator cuff tear treatment program. METHODS: Patients with chronic (>3 months), full-thickness rotator cuff tears (demonstrated on imaging) who were referred to 1 of 2 senior shoulder surgeons were enrolled in the study between October 2008 and September 2010. They participated in a comprehensive, nonoperative, home-based treatment program. After 3 months, the outcome in these patients was defined as "successful" or "failed." Patients in the successful group were essentially asymptomatic and did not require surgery. Patients in the failed group were symptomatic and consented to undergo surgical repair. All patients were followed up at 1 year, 2 years, and 5 or more years. RESULTS: At 5 or more years, all patients were contacted for follow-up; the response rate was 84%. Approximately 75% of patients remained successfully treated with nonoperative treatment at 5 years and reported a mean rotator cuff quality-of-life index score of 83 of 100 (SD, 16). Furthermore, between 2 and 5 years, only 3 patients who had previously been defined as having a successful outcome became more symptomatic and underwent surgical rotator cuff repair. Those in whom nonoperative treatment had failed and who underwent surgical repair had a mean rotator cuff quality-of-life index score of 89 (SD, 11) at 5-year follow-up. The operative and nonoperative groups at 5-year follow-up were not significantly different (P = .11). CONCLUSION: Nonoperative treatment is an effective and lasting option for many patients with a chronic, full-thickness rotator cuff tear. While some clinicians may argue that nonoperative treatment delays inevitable surgical repair, our study shows that patients can do very well over time.

Graft Augmentation Versus Bridging for Large to Massive Rotator Cuff Tears: A Systematic Review.

PURPOSE: To systematically review the literature on the healing rates and clinical outcomes of the 2 different graft indications (i.e., augmentation vs bridging) during rotator cuff repair. METHODS: A systematic literature review was performed for clinical studies of rotator cuff repair using grafts for large to massive tears. The primary outcome was tendon healing on either magnetic resonance imaging or ultrasound. The secondary outcomes included visual analog scale for pain, American Shoulder and Elbow Surgeons score, and University of California at Los Angeles score, and forward elevation. Studies were divided into augmentation and bridging groups, and outcomes were compared statistically. RESULTS: Twelve studies with 13 study groups were included: 167 repairs in the augmentation group and 247 repairs in the bridging group. For augmentation and bridging groups, the mean age was 62.2 and 62.8 years and the mean follow-up was 28.5 and 37.7 months, respectively. The estimated healing rates were 64.0% for augmentation and 77.9% for bridging. Although both procedures had improved clinical outcomes, no statistical difference between groups was detected except lower visual analog scale in the bridging group at follow-up. CONCLUSIONS: Bridging grafts had no significant difference in healing or clinical outcomes when compared with a graft used for augmentation. Bridging grafts may be considered for this difficult patient population with large to massive rotator cuff tears. LEVEL OF EVIDENCE: Level IV, systematic review of Level II to IV studies.

Arthroscopic repair of massive, contracted, immobile tears using interval slides: clinical and MRI structural follow-up.

PURPOSE: The purpose of this study was to determine clinical and structural outcomes of arthroscopic repair of massive, contracted, immobile rotator cuff tears using interval slides. METHODS: Eleven patients who had rotator cuff tears that were irreparable using standard mobilization techniques, but were repaired using interval slides were reviewed. Patients were evaluated at mean 25.2 months (±10.3) post-operatively utilizing a standardized clinical examination and by magnetic resonance imaging (MRI). RESULTS: American Shoulder and Elbow Surgeons (ASES) and Simple Shoulder Test (SST) scores improved significantly (ASES p = 0.0001; SST p = 0.0001) from pre- to post-operative. Range of motion in forward elevation and external rotation increased from pre- to post-operative, though not significantly. Strength via manual muscle testing improved on forward elevation (p = 0.001) and external rotation (p = 0.007) from pre- to post-operative. Post-operative MRI demonstrated massive re-tearing to the original size in 6 patients (55 %) and intact rotator cuffs with tissue spanning the defects in 5 (45 %) patients. CONCLUSIONS: In patients with massive, contracted, immobile tears, an interval slide technique may be utilized as a salvage procedure. Arthroscopic repair of massive, contracted, immobile rotator cuff tears using interval slide techniques can lead to good clinical and satisfactory structural outcomes. LEVEL OF EVIDENCE: IV.

Rotator cuff tears in young patients: a different disease than rotator cuff tears in elderly patients.

BACKGROUND: The purpose of this study was to conduct a systematic review of the literature to evaluate the characteristics of injury and treatment outcomes of rotator cuff tears in young patients. METHODS: A systematic electronic search was performed for clinical studies evaluating rotator cuff tears in patients younger than 40 years with special emphasis on reporting of injury characteristics and treatment outcomes with a minimum 1-year follow-up. RESULTS: Twelve studies (involving 336 patients) met inclusion criteria. The mean age of the patients was 28 years (range, 16-40 years), with a mean follow-up of 39 months. There were 2 distinct subgroups. The majority of studies (7 of 10) showed that patients typically had a full-thickness tear with an acute traumatic etiology. However, within the subgroup of elite throwers, 5 of 6 studies demonstrated a majority of tears that were partial thickness stemming from chronic overuse. Rotator cuff repair improved pain and strength in almost all studies reporting on these parameters. Eighty-seven percent of patients reported they were satisfied. However, all studies examining elite throwers showed significant difficulty in returning to play (25%-97%). CONCLUSIONS: In young patients with rotator cuff tears, there are 2 primary groups. (1) A majority group with rotator cuff tears of traumatic origin responded well to both arthroscopic and open rotator cuff repair in terms of pain relief and self-reported outcomes postoperatively. These patients reported high levels of satisfaction and return to preinjury level of play. (2) A unique subpopulation composed of elite throwers had improved outcomes but suboptimal return to play.

Validating the Glenoid Track Concept Using Dynamic Arthroscopic Assessment.

Background: Failure after isolated Bankart repair has led surgeons to consider when to address the Hill-Sachs lesion, which is thought to be a contributor to recurrent instability. One approach utilizes the glenoid track concept to determine whether a Hill-Sachs lesion is classified as "off-track," suggesting that the addition of a remplissage procedure may aid stability. However, the accuracy and reliability of using this approach require validation using an appropriate reference. Purpose: To determine the accuracy and reliability of using the glenoid track concept against dynamic arthroscopic assessment of Hill-Sachs lesion engagement. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: A total of 49 patients undergoing arthroscopic Bankart repair surgery for recurrent traumatic anterior shoulder instability were enrolled in this diagnostic validation study. Shoulders were classified as on-track or off-track using 3-dimensional computed tomography (3DCT) and static arthroscopic measurements. These classifications were compared with dynamic arthroscopic assessment (engagement of the Hill-Sachs lesion on the anterior glenoid rim in the 'athletic position') to determine their accuracy and reliability. Results: The 3DCT-based measurements to determine glenoid track status had a higher positive predictive value (66% vs 42%), higher specificity (47% vs 42%), and higher accuracy (65% vs 59%) compared with static arthroscopic measurements. Static arthroscopic measurements to determine glenoid track status had a higher negative predictive value (96% vs 64%) and higher sensitivity (96% vs 81%) compared with 3DCT-based measurements. Interrater reliability (Krippendorff α) was 'fair' for determining the glenoid track status using 3DCT (0.368; 95% CI, 0.217-0.519) and 'moderate' for static arthroscopic measurements (0.523; 95% CI, 0.364-0.666). Intrarater reliability (intraclass correlation coefficient [ICC] 3,k) was 'moderate' for 3DCT measurements (0.660; 95% CI, 0.444-0.798) and 'good' for static arthroscopic measurements (0.769; 95% CI, 0.629-0.862). Conclusion: Determining glenoid track status using either 3DCT or static arthroscopic measurements yielded moderate accuracy and reliability. Surgeons using the glenoid track concept to aid surgical decision-making in traumatic recurrent anterior shoulder instability should utilize 3DCT or static arthroscopic measurements with caution.

Strain-resolved community proteomics reveals recombining genomes of acidophilic bacteria.

Microbes comprise the majority of extant organisms, yet much remains to be learned about the nature and driving forces of microbial diversification. Our understanding of how microorganisms adapt and evolve can be advanced by genome-wide documentation of the patterns of genetic exchange, particularly if analyses target coexisting members of natural communities. Here we use community genomic data sets to identify, with strain specificity, expressed proteins from the dominant member of a genomically uncharacterized, natural, acidophilic biofilm. Proteomics results reveal a genome shaped by recombination involving chromosomal regions of tens to hundreds of kilobases long that are derived from two closely related bacterial populations. Inter-population genetic exchange was confirmed by multilocus sequence typing of isolates and of uncultivated natural consortia. The findings suggest that exchange of large blocks of gene variants is crucial for the adaptation to specific ecological niches within the very acidic, metal-rich environment. Mass-spectrometry-based discrimination of expressed protein products that differ by as little as a single amino acid enables us to distinguish the behaviour of closely related coexisting organisms. This is important, given that microorganisms grouped together as a single species may have quite distinct roles in natural systems and their interactions might be key to ecosystem optimization. Because proteomic data simultaneously convey information about genome type and activity, strain-resolved community proteomics is an important complement to cultivation-independent genomic (metagenomic) analysis of microorganisms in the natural environment.

Arthroscopic superior capsular reconstruction with dermal allograft for primary and recurrent rotator cuff tears.

Background: The aim of this study was to compare the clinical outcomes and retear rate of arthroscopic superior capsular reconstruction (SCR) with dermal allograft following structural failure of a previous rotator cuff repair, with a cohort of primary SCRs. Methods: This was a retrospective comparative study with a study group comprising 22 patients who were followed up at a minimum of 24 (mean, 41; range, 27-65) months after SCR with dermal allograft performed for structural failure of a previous rotator cuff repair. The control group included 13 patients who previously underwent a primary SCR using dermal allograft and were followed up for 24 months. Clinical outcome measures comprised range of motion, the American Shoulder and Elbow Surgeons score, and the Western Ontario Rotator Cuff (WORC) Index. Radiological outcomes included the acromiohumeral interval and graft integrity on magnetic resonance imaging at one year. Logistic regression was used to determine whether SCR being undertaken as either a primary or revision procedure influenced functional outcomes or retear rate. Results: The mean age at the time of surgery was 58 (range, 39-74) years for the study group and 60 (range, 48-70) years for the control group. Forward flexion improved from a mean of 117° (range, 7°-180°) preoperatively to 140° (range, 45°-170°) postoperatively (P = .11), and external rotation increased from a mean of 31° (range, 0°-70°) preoperatively to 36° (range, 0°-60°) postoperatively (P = .23). The American Shoulder and Elbow Surgeons score improved (P = 0) from a mean of 38 (range, 12-68) to 73 (range, 17-95), and the WORC Index improved (P = 0) from a mean of 29 (range, 7-58) to 59 (range, 30-97). Following SCR, there was no significant change in the acromiohumeral interval. The graft was intact in 42% of cases on magnetic resonance imaging and none of the retears underwent further surgery. Compared to revision SCR, primary SCR resulted in a significant improvement in forward flexion (P = .001), external rotation (P = 0), and WORC Index (P = .019). Logistic regression demonstrated that SCR performed as a revision procedure was associated with a higher retear rate (P = .006) and worse forward flexion (P = .009) and external rotation (P = .008). Conclusion: SCR using human dermal allograft following structural failure of a previous rotator cuff repair can lead to an improvement in clinical outcomes but the results are inferior to primary procedures.

Open and arthroscopic posterior bone block with iliac crest autograft for posterior shoulder instability - systematic review of clinical and radiological outcomes.

INTRODUCTION: Posterior shoulder instability (PSI) is a rare and challenging pathology to manage. The aim of this review was to assess and compare whether open and arthroscopic iliac crest bone graft (ICBG) bone block procedures succeeded in improving functional and clinical outcomes as well as radiological outcomes of union and graft resorption. HYPOTHESIS: We hypothesised that there will be no difference in recurrence rate and functional outcome between open and arthroscopic procedures but there will be a higher complication rate with open bone block procedures. METHODS: A systematic review was conducted in accordance with PRISMA guidelines using the online databases MEDLINE and Embase. The review was registered on the PROSPERO database. Studies of open or arthroscopic ICBG bone block procedures reporting patient reported outcome measures, recurrence, complications and progression to osteoarthritis and radiological outcomes of graft union and resorption were selected. Studies were appraised using the Methodical index for non-randomised studies (MINORS) tool. RESULTS: 14 studies satisfied the inclusion criteria; five studies were arthroscopic and nine used open techniques. A total of 183 patients and 201 shoulders were included, mean age was 25 years range (14-75 years). Recurrent instability ranged from 0% to 12.5% for arthroscopic and 0% to 36.4% for open studies. Arthroscopic studies had statistically significant increases in numerous functional outcome scores but there was no evidence for similar improvements in open studies. Osteoarthritis at follow-up ranged from 12.5% to 47% in arthroscopic and 0% to 81.8% for open studies. Arthroscopic complication rate ranged from 6.7% to 75% compared to 0% to 80% for open studies. Majority of complications were metalware related requiring surgical intervention. Partial graft resorption ranged from 7.7-100% after arthroscopic and 4.8-100% after open procedures. High union rates were seen with both open and arthroscopic techniques. CONCLUSION: This study highlights a lack of high-level evidence for arthroscopic and open posterior bone block procedures using ICBG to manage PSI. Functional and instability outcome scores showed significant improvement with arthroscopic ICBG bone block procedures however limited evidence was available for open studies. Metalwork related complications requiring revision and radiographic progression to osteoarthritis was high in both arthroscopic and open studies. LEVEL OF EVIDENCE: IV, systematic review.