Superior Rotator Cuff Research Articles

Anterior Capsular Reconstruction With Proximal Biceps Tendon for Large to Massive Rotator Cuff Tears

Massive rotator cuff tears (RCT) have traditionally been a challenging clinical problem for shoulder surgeons. A broad variety of treatment options have been proposed to address this problem, but outcomes have been as variable as the techniques themselves. Superior capsular reconstruction has been presented as a way to restore the restraining effect of the superior joint capsule and balanced force couples in massive tears of the superior rotator cuff. The purpose of this article is to propose a technical modification of the superior capsular reconstruction in large to massive RCT, and, especially in anterior L-shaped RCT, using the long head of the biceps tendon autograft to reinforce the weakest area of the anterior capsule, not as an augmentation of the rotator cuff, but as a static stabilizer of the humeral head, allowing the rotator cuff repair to heal without tension.

Arthroscopic Humeral Bone Tunnel–Based Tendon Grafting and Trapezius Transfer for Irreparable Posterior Superior Rotator Cuff Tear

Irreparable posterior rotator cuff tears pose challenges to orthopaedic surgeons, especially when the medial remaining rotator cuff is not reusable. Trapezius transfer is biomechanically favorable due to the similar vector of the transferred muscle to the native posterior superior rotator cuff. Regarding combined tendon grafting in trapezius transfer, onto-surface tendon attachment to the humerus was reported in most previous reports. For better tendon–humeral head connection, we introduce an humeral bone tunnel–based tendon grafting technique. In this technique, we use the hamstring tendons and the anterior half of the peroneus tendon to make 3 grafts. The most critical steps of this technique are the proper creation of the humeral tunnels and graft implantation. We consider the introduction of this technique will shed light in the field of trapezius transfer for Irreparable posterior rotator cuff tears.

Supraspinatus tendon reconstruction using open infraspinatus tendon shift and autologous biceps tendon interposition grafts

IntroductionInferior tendon quality, wide retraction, and tendon stumps that cannot be mobilized define the limits of what is technically feasible for open and arthroscopic rotator cuff reconstruction. The aim of this study was to develop a procedure that enables the open reconstruction of otherwise non-reconstructable rotator cuff tears.MethodsFrom 2014 to 2018, 23 operations were performed on 21 patients (mean age 63) using open procedure involving separating the infraspinatus tendon from the point of insertion on the greater tubercle and mobilizing it proximally and ventrally into the defective area. Any remaining defects were augmented using an autologous biceps tendon interposition graft. This augmentation was performed to achieve complete closure of the defect. Furthermore, the augmentation of the rupture zone was intended to strengthen the tendon stumps of the SSP and ISP to better neutralize the initial tensile forces. After a postoperative period of 12 months–4 years, clinical examination and functional tests were carried out, the Constant score was determined, and radiological and magnetic resonance imaging check-up examinations were performed.ResultsThe technique resulted in a low-tension closure of an otherwise “non-repairable” superior rotator cuff defect. All patients experienced a significant functional improvement, a reduction in pain, and an increase in muscle strength. An improvement in the Constant score from 48 points preoperatively to 87 points postoperatively (p < 0.05) was observed. In 19 patients (90%), the magnetic resonance image showed an intact reconstruction. Re-rupture was seen in three patients (14%).ConclusionThe surgical procedure using infraspinatus tendon shift and autologous biceps tendon interposition grafts resulted in the successful reconstruction of otherwise non-reconstructable massive rotator cuff lesions. The complete closure of the defect was observed.

The Effect of Acromioplasty on the Critical Shoulder Angle and Acromial Index

PurposeTo evaluate the effect of acromioplasty using a cutting block technique on bony coverage as measured by the critical shoulder angle (CSA) and acromial index (AI).MethodsThis study is a retrospective radiographic review using data from a previous prospective randomized clinical trial that offered enrollment to patients aged 18 years or older with a full-thickness tear of the superior rotator cuff between October 2007 and January 2011. Each patient was allocated to repair with either acromioplasty using a cutting block technique or non-acromioplasty treatment arms in a blinded fashion. Medical and demographic information was recorded for each patient. Between January 2017 and December 2017, patients were contacted for repeat follow-up clinical evaluation and radiographs. Measurements of acromial index and critical shoulder angle were performed on pre- and postoperative radiographs by a single reviewer.ResultsSeventy-one (75%) patients were available for follow up. The 2 groups were similar in terms of baseline demographics and acromial type. When compared with preoperative measures, acromioplasty did not result in significant reductions in mean CSA (34.5° vs 35.5°; P = .293) or AI (0.68 vs 0.66; P = .283). Furthermore, postoperative CSA (34.5° vs 36.2°, P = .052) and AI (0.66 vs 0.67, P = .535) demonstrated no statistically significant differences between patients with and without acromioplasty, respectively.ConclusionsThere was no statistically significant change in either the CSA or AI following acromioplasty, nor was there a significant postoperative difference in CSA or AI between the group that underwent acromioplasty and the group that did not.Clinical RelevanceSome studies suggest a greater postoperative CSA may result in greater risk of retear after arthroscopic rotator cuff repair. The CSA and AI may not be modifiable with acromioplasty.

Arthroscopic Superior Capsular Reconstruction for Treatment of Massive Irreparable Rotator Cuff Tears: An Update of the Technique for 2020.

The treatment of massive, irreparable rotator cuff tears presents a substantial challenge to health-care professionals. Treatment options range from nonoperative to operative, including debridement, partial repair, biceps tenotomy, bridging patch grafts, muscle transfers, and reverse total shoulder arthroplasty. However, the results of such treatments are often mixed, and many carry a substantial risk of complications. Superior capsular reconstruction has been described as a surgical alternative to the aforementioned procedures. Superior capsular reconstruction is a technique that provides an anatomic reconstruction of the superior capsule of the glenohumeral joint, with the goal of restoring the normal restraint to superior translation that is lost with a deficient superior rotator cuff. The technique described in the present article highlights the pearls and pitfalls learned over the last several years of performing arthroscopic reconstruction of the superior capsule with dermal allograft.

Angle of approach to the superior rotator cuff of arthroscopic instruments depends on the acromial morphology: an experimental study in 3D printed human shoulders

BackgroundPortal placement is a key factor for the success of arthroscopic procedures, particularly in rotator cuff repair. We hypothesize that the acromial anatomy may strongly determine the position of the shoulder bony landmarks and limit the surgeon’s freedom to position the arthroscopic approaches in direction towards the acromion. The purpose of this study was to analyze the relation between different acromial shapes and the freedom of movement of arthroscopic instruments relative to the rotator cuff from standardized arthroscopic portals in a laboratory study on 3D shoulder models.Methods3D models of shoulders with a broad range of different acromial shapes were printed using CT and MRI scans. Angles from the portals to defined points on the rotator cuff and the supraglenoid tubercle were measured. In conventional radiographs, the critical shoulder angle, the scapular body acromial angle, and the glenoid acromial angle were measured and compared with the measured angles to the rotator cuff.ResultsThere was a large variation of angles of approach of instruments to the rotator cuff between the seven shoulders for each portal. From the joint line portal and the posterior edge portal, the biggest angles were measured to the posterior cuff. From the intermediate portal, the angles were largest to the intermediate rotator cuff and from the anterior portals to the anterior cuff. To the supraglenoid tubercle, best access was from anterior. For all portals, there was a big correlation between the glenoid acromial angle and the scapular body acromial angle with the angles of approach to the tendon and especially to the supraglenoid tubercle.ConclusionThe access to the rotator cuff from almost every portal is influenced by the acromial shape. As hypothesized, a small (small GAA) and flat (big SBAA) acromion provide an easier approach to the rotator cuff from almost every portal. Therefore, it may severely influence the instruments maneuverability.

Mobilization After Superior Rotator Cuff Repair: Sling Versus No-Sling. A Randomized Prospective Study

Mobilization After Superior Rotator Cuff Repair: Sling Versus No-Sling. A Randomized Prospective Study

Risk of latissimus dorsi tendon rupture after arthroscopic transfer for posterior superior rotator cuff tear: a comparative analysis of 3 humeral head fixation techniques

To compare latissimus dorsi tendon rupture rates after arthroscopic transfer for posterior superior rotator cuff tear using 3 different humeral head fixation techniques. One-hundred fifty consecutive latissimus dorsi transfers were included. Inclusion criteria weremassive irreparable posterosuperior rotator cuff tear with advanced fatty infiltration associated with persistent pain and limited range of motion after failed conservative treatments or surgery. All transfers were arthroscopically assisted and fixed in a transosseous tunnel with a cortical button (group 1, n = 59), "over the top" onto the footprint of the supraspinatus (group 2, n = 47), or posteriorly onto the footprint of the infraspinatus (group 3, n = 44) with 2 suture anchors. The tendons were marked with 3 metallic clips placed intraoperatively at a fixed distance of 2, 4, and 6 cm from the tip. Immediate postoperative standard anteroposterior radiographs were performed to confirm the position of the clips and to determine whether the clips displaced on subsequent radiographs during follow-up, indicating tendon rupture. Repeat radiographs at 3-monthfollow-up showed higher risk of latissimus dorsi transfer rupture rate in 27/59 patients in group 1 (46%), 11/47 in group 2 (24%), and 7/44 in group 3 (15%). Posterior anchor fixation of the latissimus dorsi tendon onto the infraspinatus footprint had the lowest rupture rate.

Postoperative Mobilization After Superior Rotator Cuff Repair: Sling versus No-sling. A Randomized Controlled Trial: Sling versus no-sling after RCR

Objectives Patients are commonly advised to wear a sling for 4–6 weeks after rotator cuff repair (RCR) despite negative effects of early immobilization and benefits of motion rehabilitation. The study aimed to compare clinical and radiographic outcomes up to 6 months following RCR with sling immobilization and without sling immobilization. Methods We randomized 80 patients scheduled for arthroscopic repair of small or medium superior rotator cuff tears into 2 equal groups: ‘sling’ and ‘no-sling’ groups. Passive mobilization was performed in both groups during the first 4 postoperative weeks followed by a progressive active mobilization. Patients were evaluated clinically at 10 days, 1.5, 3 and 6 months, and using ultrasound at 6 months. Uni- and multi-variable analyses were performed to determine if postoperative scores are associated with gender, age at surgery, immobilization, arm dominance, biceps procedure, resection of the distal clavicle, as well as preoperative scores. Results The two groups had similar preoperative patient characteristics, function, or adjuvant procedures. At 10 days, there was no difference in pain among the two groups (5.2±2.3 vs 5.2±1.9, p=0.996). In comparison to the sling group, the no-sling group showed greater external rotation (23.5±15.6 vs 15.3±14.6, p=0.017) and active elevation (110.9±31.9 vs 97.0±25.0, p=0.038) at 1.5 months, as well as better active elevation (139.0±24.7 vs 125.8±24.4, p=0.015) and internal rotation (&gt;T12 in 50% vs 27.5%, p=0.011) at 3 months. Ultrasound revealed no differences at 6 months in tendon thickness anteriorly (p=0.472) or posteriorly (p=639), bursitis (p=1.000), echogenicity (p=0.422), or repair integrity (p=0.902). Multi-variable analyses confirmed that ASES score increased with patient age (beta, 0.60; p=0.009), SANE decreased with sling immobilization (beta, -6.3; p=0.014), and that pain increased with sling immobilization (beta, 0.77; p=0.022). Conclusion No immobilization after RCR is associated with better early mobility and functional scores in comparison to sling immobilization. Postoperative immobilization with slings may therefore not be required for patients treated for small or medium tears.

No Sling After Rotator Cuff Repair: Balancing Short-Term Benefit with Long-Term Health of Shoulder: Commentary on an article by Jérôme Tirefort, MD, et al.: "Postoperative Mobilization After Superior Rotator Cuff Repair: Sling Versus No Sling. A Randomized Prospective Study".

No Sling After Rotator Cuff Repair: Balancing Short-Term Benefit with Long-Term Health of Shoulder: Commentary on an article by Jérôme Tirefort, MD, et al.: "Postoperative Mobilization After Superior Rotator Cuff Repair: Sling Versus No Sling. A Randomized Prospective Study".

Arthroscopic repair of combined anterior and superior cuff tear

Purpose The aim of this study is to evaluate the results of arthroscopic repair of combined anterior and superior cuff tear. Patients and methods One-stage arthroscopic repair of concomitant supraspinatus and subscapularis tendon tear was performed in 25 patients. All patients were evaluated at a minimum 1-year follow-up with a visual analog scale score for pain; subjective shoulder value, which was used for subjective evaluation of the affected shoulder as a percentage of the normal one; range of motion; the American Shoulder and Elbow Surgeons score; and University of California at Los Angeles scores for clinical assessment. Belly-Press test and lift-off test, in particular back-to-hand distance, were used to evaluate subscapularis function. Empty can test was used to evaluate the supraspinatus strength. Results The mean age at the time of surgery was 53.9±11.3 years. The rate of dominant arm involvement was 60% of the patients. At the final follow-up, the mean visual analog scale score improved significantly to 0.38±0.01 points postoperatively (P Conclusion The arthroscopic tackling of concomitant shoulder anterior and superior rotator cuff tears showed satisfactory results and fastened the return to normal activity at 1-year follow-up, as well as postoperative stiffness was avoided. Level of evidence: Level III, case–control study.

Clinical and radiological effects of platelet-rich plasma on interstitial supraspinatus lesion: A randomized, double-blind, controlled trial

Aim To assess effectiveness of ultra-sound guided platelet-rich plasma infiltrations (PRP) on the supraspinatus interstitial tear healing. Background Symptomatic interstitial superior rotator cuff tear management remains challenging, as conservative management is rarely fully effective, and surgical management requires a long recovery period of 6 months. PRP infiltration might thus represent a valuable alternative. Methods We conducted a randomized, double-blind, controlled trial involving 80 patients suffering from a symptomatic isolated supraspinatus tendon interstitial tear. Patients received two intratendinous injections separated by 1 month, of either PRP (n = 41) or saline solution (n = 39). The primary outcome was tear size evolution, measured on magnetic-resonance arthrogram performed at baseline and at month 7. Results The tendon tear volume did not change between groups : 0 mm3 (range : −84 to +41) for PRP group and 9.8 mm3 (range : −264 to +270 mm3) for saline group (P = 0.175). Comparison between baseline and month 7 on the whole cohort showed a statistically significant decrease in median lesion size from 29 mm3 (range : 4–301) to 19 mm3 (range : 0–292) (P = 0.0293), and a significant improvement for all the clinical scores (VAS, SANE, Constant, and ASES scores) (P > 0.001). There were no between-group significant differences with respect to the clinical scores evolution. Main side effects identified were present on 26/80 patients (PRP : 18/41 ; control : 8/39 ; P = 0.0256), and consisted of : significant pain following injections (PRP : 11/41 ; control : 6/39), frozen shoulder (PRP : 8/41 ; control : 3/39), development of bursal- or articular-tear pattern at month 7 (PRP : 4/41 ; control : 1/39). Nine patients had to benefit a surgical rotator cuff repair after month 7 (PRP : 7/41 ; control : 2/40 ; P = 0.182). Conclusions PRP was not superior to saline injection regarding supraspinatus interstitial tear healing and clinical outcomes improvement. We observed a clinical and radiological improvement on the merged PRP and placebo groups between months 0 and 7. More side effects were observed on the PRP group. The potential costs of two PRP infiltrations are estimated as EURO 1100.

Do subscapularis tears really result in superior humeral migration?

ObjectivesThe aim of this study was to analyse the effect of subscapularis tear on superior humeral excursion (SHE) and acromiohumeral distance (AHD). The hypothesis was that subscapularis tears do not result in superior humeral excursion. MethodsPatients who underwent shoulder arthroscopy between August of 2011 and 2015 were reevaluated. Those with isolated Bankart lesion were used as control group and included in the Group 1, isolated full-thickness supraspinatus tear in the Group 2, isolated subscapularis tear in the Group 3, and combined subscapularis and supraspinatus tear in the Group 4. The mean SHE and AHD measurements on magnetic resonance imaging of these groups were compared to reveal any difference in superior humeral migration (SHM). ResultsThere were 30 patients in each group. The mean age of Group 1 (26.44 ± 8.34) was younger than the other 3 groups. The mean AHD and SHE were higher in Group 1 and 3 (Mean AHD: 12.89 ± 2.24 and 12.28 ± 1.9, respectively. Mean SHE: −3.2 ± 0.99 and −2.78 ± 0.64, respectively) than Group 2 and 4 (Mean AHD: 6.2 ± 1.78 and 6.16 ± 1.52, respectively. Mean SHE: 0.72 ± 0.65 and 1.24 ± 0.63, respectively). The AHD and SHE were strongly correlated with each other (Pearson correlation coefficient = 0.184). The inter-observer and intra-observer correlation of the measurements of SHE on MRI were excellent with intraclass correlation coefficient of 0.95 and 0.94, respectively. ConclusionSubscapularis tears do not lead to SHM and subacromial impingement. However, superior rotator cuff tears can still lead to SHM and subacromial impingement even when subscapularis tendon is intact. Level of evidenceLevel III, diagnostic study.

Biomechanical Comparison of 3 Glenoid-Side Fixation Techniques for Superior Capsular Reconstruction

Background: Superior capsular reconstruction (SCR) was recently introduced as a treatment for irreparable superior rotator cuff tears in younger patients. Purpose/Hypothesis: The purpose was to assess the biomechanical strength of 3 methods for fixation of the graft to the glenoid for SCR. It was hypothesized that a 4-anchor technique would provide greater load to failure than 3-anchor techniques. Study Design: Controlled laboratory study. Methods: Thirty-six cadaveric specimens were randomized into 3 groups of previously established glenoid-side graft fixation techniques: (1) three 3.5-mm knotless screw-in anchors, (2) three 3.0-mm knotless push-in anchors, and (3) a 4-anchor hybrid construct with two 3.0-mm knotted push-in anchors and two 2.9-mm knotless push-in anchors. The repairs were cyclically loaded at 0.5 Hz from 10 to 200 N, then pulled to failure. Elongation, stiffness, maximum load at failure, and mode of failure were recorded and calculated. Results: There were no significant differences in graft elongation or stiffness among the 3 techniques (P > .37 and P > .26, respectively). Maximum load to failure was significantly greater in technique 1 (mean ± SD, 427.85 ± 119.70 N) than technique 3 (319.5 ± 57.60 N) (P = 0.024). There were no significant differences in load to failure between techniques 1 and 2 or between techniques 2 and 3. Conclusion: Glenoid-side graft fixation with 3 threaded 3.5-mm suture anchors showed a significant superior pull-out strength when compared with a 4-anchor hybrid technique and thus might be recommended in SCR for patients with irreparable superior rotator cuff tears to achieve maximum stability. Clinical Relevance: SCR presents a novel alternative for treatment of irreparable superior rotator cuff tears in younger patients. Glenoid fixation is essential to provide adequate fixation of the graft to prevent the humeral head from rising and to restore normal biomechanics.

The high frequency of superior labrum, biceps tendon, and superior rotator cuff pathologies in patients with subscapularis tears: A cohort study.

The purpose of this study was to assess the frequency of superior labrum anterior posterior (SLAP) lesions, long head of biceps tendon (LHBT) pathologies, and superior rotator cuff tears accompanying subscapularis tears. We hypothesised that LHBT lesions, superior rotator cuff tears, and especially SLAP lesions were very frequent with subscapularis tears. The digital files of patients who underwent shoulder arthroscopy were reviewed retrospectively. One hundred and eleven patients with subscapularis tears evident on surgery videos were examined. Superior labrum, LHBT, and superior rotator cuff lesions were investigated by the authors of this study. The statistical analyses were made with SPSS statistics software, and significance was set at P<0.05 value. There were 111 patients with both subscapularis tears and surgery videos. The mean age was 58.09±10.21, and 63.1% of the patients were female. 98.2% of the 111 patients had a SLAP lesion. 7.2% of those were SLAP I and 91% were SLAP II lesions while 1.8% were healthy. The 75.7% of the patients had a LHBT pathology, and 83.8% had superior cuff tear. Subscapularis tears were almost always accompanied by SLAP lesions. On the other hand, biceps tendon pathologies and superior rotator cuff tears were also very frequent with subscapularis tears. Prognostic study, Level IV (retrospective cohort study).

The female geriatric proximal humeral fracture: protagonist for straight antegrade nailing?

IntroductionStraight antegrade humeral nailing (SAHN) has become a standard technique for the surgical fixation of proximal humeral fractures, which predominantly affect elderly females. The nail’s proximal anchoring point has been demonstrated to be critical to ensure reliable fixation in osteoporotic bone and to prevent iatrogenic damage to the superior rotator cuff bony insertion. Anatomical variations of the proximal humerus, however, may preclude satisfactory anchoring of the nail’s proximal end and may bare the risk of rotator cuff violation, even though the nail is inserted as recommended. The aim of this study was to evaluate the anatomical suitability of proximal humeri of geriatric females aged 75 years and older for SAHN. Specifically, we sought to assess the proportion of humeri not anatomically amenable to SAHN for proximal humeral fracture.Materials and MethodsA total of 303 proximal humeri of 241 females aged 75 years and older (mean age 84.5 ± 5.0 years; range 75–102 years) were analyzed for this study. Multiplanar two-dimensional reformations (true ap, true lateral, and axial) were reconstructed from shoulder computed tomography (CT) data sets. The straight antegrade nail’s ideal entry point, “critical point” (CP), and critical distance (CD; distance between ideal entry point and CP) were determined. The rate of proximal humeri not anatomically suitable for SAHN (critical type) was assessed regarding proximal reaming diameters of currently available straight antegrade humeral nails.ResultsOverall, 35.6% (108/303) of all proximal humeri were found to be “critical types” (CD <8 mm) as to the recommended minimal proximal reaming diameter of 10 mm of straight antegrade nails currently in use. Moreover, 43.2% (131/303) of the humeri were considered “critical types” with regard to the alternatively used larger proximal reaming diameter of 11.5 mm. Mean CD was 9.0 ± 1.7 mm (range 3.5–13.5 mm) and did not correlate with age (r = −0.04, P = 0.54). No significant differences in CD and rate of “critical types” were found between left and right humeri as well as between females aged between 75 and 84 years (n = 151) and females aged 85 and older (n = 152).ConclusionsMore than a third of proximal humeri of geriatric females are “critical types” as to SAHN and may, therefore, be at risk for procedure-related complications, such as rotator cuff violation, fixation failure, and potential malreduction. In view of this finding, we recommend to routinely analyze multiplanar CT reformations of the uninjured contralateral side prior to surgery to improve selection of patients for SAHN and to minimize foreseeable complications. For “critical type” humeri, an alternative surgical procedure should be considered.

The Rotator Cuff and the Superior Capsule: Why We Need Both

Tears of the rotator cuff are frequent. An estimated 250,000 to 500,000 repairs are performed annually in the United States. Rotator cuff repairs have been successful despite fatty infiltration and atrophy of the rotator cuff muscles. Although the emphasis in rotator cuff repair has historically focused on re-establishing the tendon attachment, there is growing interest in and understanding of the role of the superior capsule. The superior capsule is attached to the undersurface of the supraspinatus and infraspinatus muscle-tendon units, and it resists superior translation of the humeral head. Herein, we propose that it is the defect in the superior capsule that is the “essential lesion” in a superior rotator cuff tear, as opposed to the defect in the rotator cuff itself. We propose that rotator cuff repair must restore the normal capsular anatomy to provide normal biomechanics of the joint and thus a positive clinical outcome.

Perioperative Rotator Cuff Injury and Disease With Anatomic Total Shoulder Arthroplasty

Rotator cuff disease is a relatively uncommon but important complication in total shoulder arthroplasty (TSA). Posterior superior cuff injury is not commonly encountered in the setting of glenohumeral osteoarthritis, but has been reported in 5% to 10% of standard anatomic shoulder replacements. In these cases, cuff lesions that are small or moderate are usually amenable to direct repair during the time of standard arthroplasty implantation. Glenoid component implantation is typically avoided in patients with massive tears due to concerns for eccentric wear of the component from abnormal humeral shear forces. Rotator cuff disease in the postoperative setting after standard TSA may occur either traumatically or chronically. Traumatic rupture of the subscapularis is a challenging problem that typically requires surgical repair of the tendon or consideration for capsular reconstruction with allograft and pectoralis major transfer if the tendon is irreparable. Chronic secondary cuff dysfunction affects the posterior superior rotator cuff and has been reported in up to 55% of the patients with retained implants over 15 years. For these patients, conversion to a reverse TSA has demonstrated adequate clinical outcomes.

Influence of rotator cuff tears on glenohumeral stability during abduction tasks.

One of the main goals in reconstructing rotator cuff tears is the restoration of glenohumeral joint stability, which is subsequently of utmost importance in order to prevent degenerative damage such as superior labral anterior posterior (SLAP) lesion, arthrosis, and malfunction. The goal of the current study was to facilitate musculoskeletal models in order to estimate glenohumeral instability introduced by muscle weakness due to cuff lesions. Inverse dynamics simulations were used to compute joint reaction forces for several static abduction tasks with different muscle weakness. Results were compared with the existing literature in order to ensure the model validity. Further arm positions taken from activities of daily living, requiring the rotator cuff muscles were modeled and their contribution to joint kinetics computed. Weakness of the superior rotator cuff muscles (supraspinatus; infraspinatus) leads to a deviation of the joint reaction force to the cranial dorsal rim of the glenoid. Massive rotator cuff defects showed higher potential for glenohumeral instability in contrast to single muscle ruptures. The teres minor muscle seems to substitute lost joint torque during several simulated muscle tears to maintain joint stability. Joint instability increases with cuff tear size. Weakness of the upper part of the rotator cuff leads to a joint reaction force closer to the upper glenoid rim. This indicates the comorbidity of cuff tears with SLAP lesions. The teres minor is crucial for maintaining joint stability in case of massive cuff defects and should be uprated in clinical decision-making. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1628-1635, 2016.

Superior Capsule Reconstruction Technique Using an Acellular Dermal Allograft

Chronic, massive, irreparable rotator cuff tears remain one of the most challenging pathologies in shoulder surgery to treat. Because of this, many treatment options exist for the management of chronic retracted rotator cuff tears. Superior capsule reconstruction is one option that provides the potential to restore and rebalance the force couples necessary for dynamic shoulder function. We describe an all-arthroscopic technique using an acellular dermal allograft for superior capsule reconstruction indicated for patients with a deficient superior rotator cuff. This technique provides an option for patients with an irreparable rotator cuff tear without compromising future treatment options. Although this is a relatively new and unproven method for treating chronic irreparable rotator cuff tears, our short-term results are promising. Nevertheless, larger studies with long-term follow-up are required to fully evaluate the success of this technique.