Supraspinatus Repair Research Articles

Early postoperative repair status after rotator cuff repair cannot be accurately classified using questionnaires of patient function and isokinetic strength evaluation

This study investigated if patients with an intact tendon repair or partial-thickness retear early after rotator cuff repair display differences in clinical evaluations and whether early tendon healing can be predicted using these assessments. We prospectively evaluated 60 patients at 16weeks after arthroscopic supraspinatus repair. Evaluation included the Oxford Shoulder Score, 11-item version of the Disabilities of the Arm, Shoulder and Hand, visual analog scale for pain, 12-item Short Form Health Survey, isokinetic strength, and magnetic resonance imaging (MRI). Independent t tests investigated clinical differences in patients based on the Sugaya MRI rotator cuff classification system (grades 1, 2, or 3). Discriminant analysis determined whether intact repairs (Sugaya grade 1) and partial-thickness retears (Sugaya grades 2 and 3) could be predicted. No differences (P<.05) existed in the clinical or strength measures. Although discriminant analysis revealed the 11-item version of the Disabilities of the Arm, Shoulder and Hand produced a 97% true-positive rate for predicting partial thickness retears, it also produced a 90% false-positive rate whereby it incorrectly predicted a retear in 90% of patients whose repair was intact. The ability to discriminate between groups was enhanced with up to 5 variables entered; however, only 87% of the partial-retear group and 36% of the intact-repair group were correctly classified. No differences in clinical scores existed between patients stratified by the Sugaya MRI classification system at 16weeks. An intact repair or partial-thickness retear could not be accurately predicted. Our results suggest that correct classification of healing in the early postoperative stages should involve imaging.

A 3D finite element model for geometrical and mechanical comparison of different supraspinatus repair techniques

Contact pressure and contact area are among the most important mechanical factors studied to predict the effectiveness of a rotator cuff repair. The suture configurations can strongly affect these factors but are rarely correlated with each other. For example, there is a significant difference between the single-row technique and the transosseous or transosseous-like approaches in terms of footprint contact area coverage. A finite element model-based approach is presented and applied to account for various parameters (eg, suture pretension, geometry of the repair, effect of the sutures, geometry of the lesion) and to compare the efficacy of different repair techniques in covering the original footprint. The model allows us to evaluate the effect of parameters such as suture configuration and position and suture pretension. The validity of such an approach was assessed in comparing 3 different repair techniques: single row, transosseous equivalent, and double row. Results from the application of the models show that the double-row and transosseous-equivalent techniques lead to progressive increase of the contact area compared with the single-row approach, supporting the conclusion that transosseous-equivalent fixation leads to an increase of the contact area and a better distribution of the pressure coverage. The 3-dimensional finite element model approach allows multiple variables to be assessed singularly, weighing the specific influence. Moreover, the approach presented in this study could be a valid tool to predict and to reproduce different configurations, identifying how to reduce the stress over the tendon and when a repair could be effective or not.

Do Postoperative Platelet-Rich Plasma Injections Accelerate Early Tendon Healing and Functional Recovery After Arthroscopic Supraspinatus Repair?

Background: Tendon-bone healing after rotator cuff repair directly correlates with a successful outcome. Biological therapies that elevate local growth-factor concentrations may potentiate healing after surgery. Purpose: To ascertain whether postoperative and repeated application of platelet-rich plasma (PRP) to the tendon repair site improves early tendon healing and enhances early functional recovery after double-row arthroscopic supraspinatus repair. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 60 patients underwent arthroscopic double-row supraspinatus tendon repair. After randomization, half the patients received 2 ultrasound-guided injections of PRP to the repair site at postoperative days 7 and 14. Early structural healing was assessed with MRI at 16 weeks, and cuff appearances were graded according to the Sugaya classification. Functional scores were recorded with the Oxford Shoulder Score; Quick Disability of the Arm, Shoulder and Hand; visual analog scale for pain; and Short Form–12 quality-of-life score both preoperatively and at postoperative weeks 6, 12, and 16; isokinetic strength and active range of motion were measured at 16 weeks. Results: PRP treatment did not improve early functional recovery, range of motion, or strength or influence pain scores at any time point after arthroscopic supraspinatus repair. There was no difference in structural integrity of the supraspinatus repair on MRI between the PRP group (0% full-thickness retear; 23% partial tear; 77% intact) and the control group (7% full-thickness retear; 23% partial tear; 70% intact) at 16 weeks postoperatively (P = .35). Conclusion: After arthroscopic supraspinatus tendon repair, image-guided PRP treatment on 2 occasions does not improve early tendon-bone healing or functional recovery.

Silencing of TGIF1 in bone mesenchymal stem cells applied to the post-operative rotator cuff improves both functional and histologic outcomes.

Stem cells have long been hypothesized to improve outcomes following rotator cuff repair. However, these cells must be signaled in order to do so. TGIF1 is a transcription factor that has been found to be down-regulated in cells involved in chondrogenesis. We therefore wished to examine whether stem cells expressing lower levels of TGIF1 could better improve outcomes following rotator cuff repair than stem cells expressing normal levels of TGIF1. Bone mesenchymal stem cells (BMSCs) were transduced with TGIF1 siRNA to suppress native TGIF1. Nontransduced BMSCs were also obtained for the control group. Following suprapinatus tendon repair, rats were either treated with transduced BMSCs or nontransduced BMSCs. Histologic and functional testing were performed on both groups. Rats treated with transduced TGIF1 siRNA BMSCs following suprapinatus repair expressed significantly higher levels of chondrogenic proteins at 4 weeks than rats treated with nontransduced BMSCs. Further, rats treated with BMSCs transduced with TGIF1 siRNA had both a significantly greater maximum load at failure and stiffness. Rats treated with transduced TGIF1 siRNA BMSCs following supraspinatus repair perform better both histologically and functionally at 4 weeks.

Effect of scapular dyskinesis on supraspinatus repair healing in a rat model

Rotator cuff tears are common conditions that often require surgical repair to improve function and to relieve pain. Unfortunately, repair failure remains a common problem after rotator cuff repair surgery. Several factors may contribute to repair failure, including age, tear size, and time from injury. However, the mechanical mechanisms resulting in repair failure are not well understood, making clinical management difficult. Specifically, altered scapular motion (termed scapular dyskinesis) may be one important and modifiable factor contributing to the risk of repair failure. Therefore, the objective of this study was to determine the effect of scapular dyskinesis on supraspinatus tendon healing after repair. A rat model of scapular dyskinesis was used. Seventy adult male Sprague-Dawley rats (400-450 g) were randomized into 2 groups: nerve transection of the accessory and long thoracic nerves (SD) or sham nerve transection (Sham control). After this procedure, all rats underwent unilateral detachment and repair of the supraspinatus tendon. All rats were sacrificed at 2, 4, and 8 weeks after surgery. Shoulder function, passive joint mechanics, and tendon properties (mechanical, histologic, organizational, and compositional) were evaluated. Scapular dyskinesis alters joint function and may lead to compromised supraspinatus tendon properties. Specifically, diminished mechanical properties, altered histology, and decreased tendon organization were observed for some parameters. This study identifies scapular dyskinesis as one underlying mechanism leading to compromise of supraspinatus healing after repair. Identifying modifiable factors that lead to compromised tendon healing will help improve clinical outcomes after repair.

Effect of intramuscular botulinum toxin-A in a rat rotator cuff repair model: an experimental study.

Rotator cuff repair is associated with multiple complications, significant morbidity, and reintervention, which could be mitigated by postoperative chemodeneveration with botulinum toxin-A (BTX-A). This study evaluated the antinociceptive and paralytic effects of BTX-A on an experimental supraspinatus repair rat model and its effect on functional outcomes (running performance). Thirty rats were grouped into the surgical repair group (group A), repair + intramuscular BTX-A group (group B), or control group (group C). At the end of the 3-month follow-up, running performance of the rats on a motorized treadmill was evaluated in four time periods (0-30 min, 30-60 min, 60-90 min, and 90-110 min), and penalty points (i.e., number of shock stimuli per lane) were recorded. Afterwards, the supraspinatus muscles were removed and evaluated histologically. Regarding running performance, group B received significantly fewer penalty points than did group A (p<0.05). The penalty points received were not significantly different between groups B and C in the first three time periods, but were significantly higher in group B at the 90-110-min interval than in group C. On necropsy, all repaired tendons were intact, with no sign of failure at the repair site. Histological evaluation revealed marked degeneration and necrosis of muscles in both repair groups, which was much less evident in group B. Groups A and B had less fatty infiltration than group C. BTX-A injections resulted in a better function based on running performance, probably due to decreased tissue tension at the repair site and less pain. Further studies on humans are needed to demonstrate this effect clinically.

Biomechanical Analysis of Articular-Sided Partial-Thickness Rotator Cuff Tear and Repair

Background: Articular-sided partial-thickness rotator cuff tears are common injuries in throwing athletes. The superior shoulder capsule beneath the supraspinatus and infraspinatus tendons works as a stabilizer of the glenohumeral joint. Purpose: To assess the effect of articular-sided partial-thickness rotator cuff tear and repair on shoulder biomechanics. The hypothesis was that shoulder laxity might be changed because of superior capsular plication in transtendon repair of articular-sided partial-thickness rotator cuff tears. Study Design: Controlled laboratory study. Methods: Nine fresh-frozen cadaveric shoulders were tested by using a custom shoulder-testing system at the simulated late-cocking phase and acceleration phase of throwing motion. Maximum glenohumeral external rotation angle, anterior translation, position of the humeral head apex with respect to the glenoid, internal impingement area, and glenohumeral and subacromial contact pressures were measured. Each specimen underwent 3 stages of testing: stage 1, with the intact shoulder; stage 2, after creation of articular-sided partial-thickness tears of the supraspinatus and infraspinatus tendons; and stage 3, after transtendon repair of the torn tendons by using 2 suture anchors. Results: Articular-sided partial-thickness tears did not significantly change any of the shoulder biomechanical measurements. In the simulated late-cocking phase, transtendon rotator cuff repair resulted in decreased maximum external rotation angle by 4.2° (P = .03), posterior shift of the humeral head (1.1-mm shift; P = .02), decreased glenohumeral contact pressure by 1.7 MPa (56%; P = .004), and decreased internal impingement area by 26.4 mm2 (65%; P < .001) compared with values in the torn shoulder. In the acceleration phase, the humeral head shifted inferiorly (1.2-mm shift; P = .03 vs torn shoulder), and glenohumeral anterior translation (1.5-mm decrease; P = .03 vs torn shoulder) and subacromial contact pressure (32% decrease; P = .004 vs intact shoulder) decreased significantly after transtendon repair. Conclusion: Transtendon repair of articular-sided partial-thickness supraspinatus and infraspinatus tears decreased glenohumeral and subacromial contact pressures at time zero; these changes might lead to reduced secondary subacromial and internal impingements and consequently progression to full-thickness rotator cuff tear. However, repair of the tendons decreased anterior translation and external rotation and changed the positional relationship between the humeral head and the glenoid. Clinical Relevance: Careful attention should be paid to shoulder laxity and range of motion when transtendon repair is chosen to treat articular-sided partial-thickness rotator cuff tears, specifically in throwing athletes.

Effect of glenohumeral abduction on supraspinatus repair tension

A pilot x-ray study was performed on three healthy subjects using a x-ray fluoroscopy InSight (Hologic, Inc. Bedford, MA, USA) in true anterior-posterior (AP) view, to determine what position the shoulder is placed in when wearing a sling only (Donjoy Ultrasling II (DJO, Normanhurst, NSW, Australia)), sling with small abduction pillow (Donjoy Ultrasling II (DJO)) and sling with large abduction pillow (ProCare Shoulder Abduction Kit (DJO)). Figure 1: AP view of a shoulder X-Ray

Relative Fixation Strength of Rabbit Subscapularis Repair Is Comparable to Human Supraspinatus Repair at Time 0

Recent evidence suggests that the rabbit subscapularis tendon may be anatomically, biomechanically, and histologically suitable to study rotator cuff pathology and repair. However, biomechanical comparisons of rotator cuff repairs in this model have not been evaluated and compared to those in human cadaveric specimens. We quantified the biomechanical properties of the repaired rabbit subscapularis tendon after (1) single-row, (2) double-row, and (3) transosseous-equivalent rotator cuff repair techniques and compared the ratios of repairs to previously published data for human repairs. Tensile testing was performed on 21 New Zealand White rabbit subscapularis tendon-humerus complexes for single-row repair, double-row repair, and transosseous-equivalent repair (n = 7 for each group). Video digitizing software was used to quantify deformation. Load elongation data were then used to quantify structural properties. We compared the ratios of rotator cuff repairs for the rabbit data to data from human supraspinatus repair studies previously performed in our laboratory. For our primary end points (linear stiffness, yield load, ultimate load, and energy absorbed to failure), with the numbers available, our statistical power to detect a clinically important difference (defined as 15%) was 85%. The ratios of single-row/double-row repair were 0.72, 0.73, 0.71, and 0.66 for human supraspinatus and 0.77, 0.74, 0.79, and 0.89 for rabbit subscapularis repair for linear stiffness, yield load, ultimate load, and energy absorbed to failure, respectively. The ratios of double-row/transosseous-equivalent repair were 1.0, 0.86, 0.70, and 0.41 for human supraspinatus and 1.22, 0.85, 0.76, and 0.60 for rabbit subscapularis for linear stiffness, yield load, ultimate load, and energy absorbed to failure, respectively. There were no differences comparing rabbit to human repair ratios for any parameter (p > 0.09 for all comparisons). Subscapularis repairs in the rabbit at Time 0 result in comparable ratios to human supraspinatus repairs. The biomechanical similarities between the different types of rotator cuff repair in the rabbit subscapularis and human supraspinatus at Time 0 provide more evidence that the rabbit subscapularis may be an appropriate model to study rotator cuff repairs.

The influence of partial subscapularis tendon tears combined with supraspinatus tendon tears

With the advent of arthroscopy, more partial subscapularis tears are being recognized. The biomechanical effects of partial subscapularis tears are unknown, and there is no consensus as to their treatment. Therefore, the objective of this study was to evaluate and to quantify the changes in range of motion and glenohumeral kinematics for isolated subscapularis partial tears, combined subscapularis and supraspinatus tears, supraspinatus repair, and combined supraspinatus and subscapularis repair. Six cadaveric shoulders were tested in the scapular plane with 0°, 30°, and 60° shoulder abduction under 6 conditions: intact; ¼ subscapularis tear; ½ subscapularis tear; ½ subscapularis and complete supraspinatus tear; supraspinatus repair; and supraspinatus and subscapularis repair. Maximum internal and external rotation and glenohumeral kinematics were measured under physiologic muscle loading condition. A repeated measures analysis of variance with a Tukey post hoc test was used for statistical analysis. Maximum external rotation was significantly increased after ¼ subscapularis tear at 30° abduction and in all abduction angles with ½ subscapularis tear (P < .05). The 2 repair conditions did not restore external rotation to the intact level. At maximum internal and external rotation, there was a significant superior shift in the humeral head apex position with ¼ subscapularis tear at 30° abduction and with ½ subscapularis tear at 60° abduction (P < .05). Repair of the supraspinatus tendon partially corrected abnormal kinematics; however, neither repair restored abnormal kinematics to intact. Additional repair of the partial subscapularis tear with supraspinatus tear did not affect external rotation or glenohumeral kinematics. Further studies are needed to evaluate different subscapularis repair techniques. Basic science study, biomechanics.

Anterior Capsulolabral Lesions Combined With Supraspinatus Tendon Tears: Biomechanical Effects of the Pathologic Condition and Repair in Human Cadaveric Shoulders

Our purpose was to investigate the effect of supraspinatus tendon tear combined with anterior capsulolabral injury on glenohumeral joint biomechanics and to identify which structures should be repaired when both pathologic conditions are present. Eight cadaveric shoulders were tested on a custom system. Five conditions were tested: intact supraspinatus full-thickness tear, supraspinatus tear combined with Bankart lesion, supraspinatus repair, and supraspinatus repair combined with Bankart repair. Rotational range of motion, glenohumeral kinematics, and the force required for anteroinferior dislocation were measured at 30° and 60° of glenohumeral abduction. Repeated-measures analysis of variance with Tukey post hoc test was used for statistical analysis. Bankart lesions combined with supraspinatus tears significantly increased total rotational range of motion (7.6° ± 6.3° at 30° of glenohumeral abduction and 14.1° ± 10.3° at 60° of glenohumeral abduction; P < .05). Bankart lesions combined with supraspinatus tears also significantly decreased the force required for dislocation normalized to range of motion (26.6% ± 21.0% at 60° of abduction) compared with intact shoulders (P= .04). Bankart repair combined with supraspinatus repair restored range of motion and the force required for dislocation; however, Bankart repair combined with supraspinatus repair shifted the humeral head posteriorly at the midrange of rotation in 30° and 60° of abduction (P < .05). Supraspinatus tendon tears combined with Bankart lesions increased humeral rotational range of motion and decreased the force required for dislocation. Repair of both pathologic conditions successfully restored range of motion and increased the force required for dislocation. Both supraspinatus tendon and anterior labral repair are suggested for patients with combined Bankart lesions and supraspinatus tears to restore shoulder function and possibly prevent recurrent dislocation. However, when repairing both pathologic conditions, care should be taken not to overtighten the joint, which may lead to stiffness or osteoarthritis.

Biomechanical evaluation of augmentation of suture-bridge supraspinatus repair with additional anterior fixation

Studies have recently focused on evaluating the ability of the supraspinatus repair to withstand rotational loads. Other studies have focused on the importance of minimizing gap formation to avoid decreased healing and failure of repair. The objective of this study was to use a loading model that incorporates external rotation to biomechanically evaluate augmenting a suture-bridge technique for supraspinatus repair with an additional anterior fixation. Eight matched cadaveric shoulder pairs were randomized to 2 different types of repairs after a simulated supraspinatus tear. One group received a standard suture-bridge technique, and the other underwent a suture-bridge repair with an additional anterior fixation consisting of a 4.5-mm suture anchor. A custom apparatus was used to test all specimens, allowing for dynamic external rotation from 0° to 30° during loading. Cyclic loading was performed for 30 cycles from 0 to 90 N, followed by load to failure using a materials-testing machine. No differences were found in linear stiffness, yield load, ultimate load, and energy absorbed for load to failure between the 2 groups (P > .05). There was a reduction in anterior gapping at ultimate load between the anterior augmentation repair group (6.4 ± 3.1 mm) and the standard suture bridge (9.4 ± 2.8 mm; P = .037). There does not appear to be a biomechanical advantage with the addition of an anterior suture augmentation of a suture bridge for a supraspinatus repair. However, using an anterior augmentation for a suture bridge prevents gap formation at ultimate load in a biomechanical, dynamic external rotation model.

Erratum to “Suprascapular neuropathy: what does the literature show?” [J Shoulder Elbow Surg 2012; vol 2,1 no 6, pp 835-46

In the abovementioned article, Figures 3 and 5 are reprinted illustrations for which the authors received permission to reproduce. Acknowledgment of permission was not included in the original figure legends. The figure legends, including the acknowledgment of items borrowed, are reprinted below. Figure 3 A schematic shows a massive rotator cuff tear, with retraction of the tear causing a traction injury to the suprascapular nerve at the suprascapular notch. (Reprinted with permission from Elsevier; Lafosse et al. Arthroscopic release of suprascapular nerve entrapment at the suprascapular notch: technique and preliminary results. Arthroscopy 2007;23:34-42. http://dx.doi.org/10.1016/j.arthro.2006.10.003.) Figure 5 A schematic shows resolution of the traction and compression on the suprascapular nerve with repair of the massive rotator cuff tear. (Reprinted with permission from Elsevier; Costouros et al. Reversal of suprascapular neuropathy following arthroscopic repair of massive supraspinatus and infraspinatus rotator cuff tears. Arthroscopy 2007; 23:1152-61. http://dx.doi.org/10.1016/j.arthro.2007.06.014.) The publisher and production staff apologize for this oversight and for any inconvenience caused to the authors or readership. Suprascapular neuropathy: what does the literature show?Journal of Shoulder and Elbow SurgeryVol. 21Issue 6PreviewSuprascapular neuropathy remains a rare, albeit increasingly recognized, diagnosis. Despite its relatively low prevalence, it must be kept in the shoulder surgeon’s mind as a potential cause of shoulder pain, particularly in patients where the history, physical examination, and imaging studies do not adequately explain a patient’s symptoms or disability. Although challenging to identify, suprascapular neuropathy can be successfully treated. The current literature shows that the location and mechanism of nerve injury are the most important factors guiding management. Full-Text PDF

Retraction of Supraspinatus Muscle and Tendon as Predictors of Success of Rotator Cuff Repair

Background: The structural failure rate of rotator cuff repair can exceed 50%. Important predictors for repair failure are preoperative fatty muscle infiltration and myotendinous retraction. Purpose: To quantitatively assess the prognostic value of preoperative retraction of both the supraspinatus muscle and tendon for the outcome of supraspinatus repair. Study Design: Cohort study; Level of evidence, 3. Methods: In 33 shoulders with complete supraspinatus tendon ruptures subjected to arthroscopic repair, magnetic resonance imaging (MRI) scans taken preoperatively and after a mean follow-up of 24 months were studied. The exact position of the lateral extension of the supraspinatus muscle and of the tendon end was evaluated and correlated with the preoperative stage of fatty infiltration (Goutallier) and the failure rate of tendon repair. Results: The mean lengthening of the muscle and tendon end was −3 mm and 4 mm in the failed repairs (n = 19) and 14 mm and 8 mm in the successful repairs (n = 14). If the supraspinatus had preoperative Goutallier stages 2 to 3 and a tendon length of less than 15 mm, the failure rate was 92%, but if the tendon length was greater than 15 mm, the failure rate was only 33%. With Goutallier stages 0 to 1, the corresponding failure rates were 57% and 25%, respectively. Conclusion: Rotator cuff repair lengthens the tendon, even if the repair fails. The possibility to lengthen the myotendinous unit is related to the preoperative length of the tendon. The combination of Goutallier grading and preoperative tendon length appears to be a more powerful predictor for the reparability of a tendon tear than Goutallier grading alone.

Fiber-aligned polymer scaffolds for rotator cuff repair in a rat model

Repair techniques of rotator cuff tendon tears have improved in recent years; nonetheless, the failure rate remains high. Despite the availability of various graft materials for repair augmentation, there has yet to be a biomechanical study using fiber-aligned scaffolds invivo. The objective of this study was to evaluate the efficacy of fiber-aligned nanofibrous polymer scaffolds as a potential treatment-delivery vehicle in a rat rotator cuff injury model. Scaffolds with and without sacrificial fibers were fabricated via electrospinning and implanted to augment supraspinatus repair in rats. Repairs without scaffold augmentation were also performed to serve as controls. Rats were sacrificed at 4 and 8 weeks postoperatively, and repairs were evaluated histologically and biomechanically. Both scaffold formulations remained in place, with more noticeable cellular infiltration and colonization at 4 and 8 weeks after injury and repair for scaffolds lacking sacrificial fibers. Specimens with scaffolds were larger in cross-sectional area compared with controls. Biomechanical testing revealed no significant differences in structural properties between the groups. Some apparent material properties were significantly reduced in the scaffold groups. These reductions were due to increases in cross-sectional area, most likely caused by the extra thickness of the implanted scaffold material. No differences were observed between the 2 scaffold groups. No adverse effect of surgical implantation of overlaid fiber-aligned scaffolds on structural properties of supraspinatus tendons in rat rotator cuff repair was demonstrated, validating this model as a platform for targeted delivery.

Combined tears of the subscapularis and supraspinatus tendon: clinical outcome, rotator cuff strength and structural integrity following open repair

Anterosuperior rotator cuff tears involving the subscapularis and supraspinatus tendons are less common than other tears of the rotator cuff. The purpose of this study was to report the clinical outcome, rotator cuff strength and structural integrity of open repair of combined anterosuperior rotator cuff tears. Forty-eight patients at an average age of 58 years underwent open repair of a combined supraspinatus and subscapularis tendon tear. The follow-up evaluation included clinical scores, rotator cuff strength testing with a custom-made force measurement plate (FMP) and postoperative MRI to evaluate repair integrity and muscle cross-sectional area. After a mean follow-up of 49 months the average Constant score improved from 43 points preoperatively to 79 points postoperatively. The SST and the pain VAS were significantly improved by the procedure (each <0.05). The combined tear group with partial subscapularis tears (G1) did not achieve significantly better score results than the combined tear group with a full-thickness subscapularis tear (G2) (p > 0.05). Strength for all rotator cuff components was reduced significantly (p < 0.05) compared with the contralateral shoulder in both groups. MRI revealed a retear-rate of 4% for the subscapularis and a retear-rate of 19% for the supraspinatus. Postoperative muscle cross-sectional area of all rotator cuff muscles did not differ significantly between G1 and G2 (p > 0.05). Open repair of combined anterosuperior rotator cuff tears achieved good postoperative results despite a residual rotator cuff strength deficit. Combined supraspinatus-/full-thickness subscapularis tears achieved equal clinical and radiographic results compared with supraspinatus-/partial-thickness subscapularis tears.

Fatal Venous Air Embolism During Shoulder Arthroscopy

Venous air embolism is a potential surgical complication when a negative pressure gradient exists between the surgical site and the right atrium of the heart. It occurs more commonly when the operative site is over the heart, the pressure of gas in the body cavity exceeds that of the venous sinusoids (15 to 30 mm Hg), air rather than carbon dioxide is injected, or the venous sinusoids of bone marrow are exposed1,2. Shoulder arthroscopy satisfies many of these criteria: the beach-chair and lateral decubitus positions place the surgical site over the right atrium, the standard settings for arthroscopic pumps are at pressures of >30 mm Hg, air bubbles are often observed entering the joint, and venous sinusoids are exposed anytime that osseous work (i.e., distal clavicular excision, acromioplasty, or fracture repair) is performed. Two case reports of fatal venous air embolism following knee arthroscopy3,4 with intentional air insufflation have appeared in the literature, but we are not aware of any reported case following liquid-only arthroscopy. We present the case of a patient undergoing revision arthroscopic rotator cuff repair and distal clavicular excision who experienced acute intraoperative cardiopulmonary collapse and was resuscitated, but died on postoperative day 14. The patient was undergoing liquid-only arthroscopy, and we postulated that air entered the joint through an unrecognized air reservoir: commercially available 3-L arthroscopic fluid bags. A forty-seven-year-old woman presented with a six-month history of severe pain in the right shoulder. The history, physical examination, and magnetic resonance imaging revealed a small, full-thickness tear of the supraspinatus tendon. After the failure of six months of conservative treatment, she elected to undergo arthroscopic supraspinatus repair and subacromial …

Simultaneous Acute Rotator Cuff Tear and Distal Biceps Rupture in a Strongman Competitor

Acute rotator cuff tear is commonly associated with tearing of the proximal biceps tendon, but has never been reported to occur simultaneously with a distal biceps tendon rupture. A 38-year-old right-hand-dominant strongman competitor attempted a 300-pound overhead axle press and experienced immediate pain in the right shoulder and elbow. He had no known systemic risk factors for tendon ruptures including hyperparathyroidism, hemodialysis, alcoholism, rheumatoid arthritis, statin medications, fluoroquinolones, and steroid use.Right shoulder magnetic resonance imaging (MRI) showed a full-thickness supraspinatus tear with 3 cm of retraction. There was minimal fatty infiltration of the supraspinatus on the sagittal cuts consistent with acute rupture. The subscapularis was intact. The long head of the biceps tendon had mild medial subluxation but was completely within the bicipital groove. Right elbow MRI showed a complete distal biceps tendon rupture. Thirteen days after his injury, the patient underwent arthroscopic supraspinatus repair and proximal biceps tenodesis. Distal biceps tendon repair was performed using the modified 2-incision muscle-splitting technique. At 24-month follow-up, the patient was pain free and had returned to full activity including weightlifting but had not returned to strongman competition.This is the first report of simultaneous acute full thickness ruptures of the rotator cuff and distal biceps tendon. This case report underscores the importance of a complete physical examination and a high index of suspicion for additional concomitant injuries, particularly in athletes with unusually high stresses to the body.

Differential Suture Loading in an Experimental Rotator Cuff Repair

Background Repairs of large rotator cuff tears often fail to heal. A possible factor in these failures is excessive tension in the repair sutures, causing them to pull through the tendon. Hypothesis Arm positions encountered during early rehabilitation after cuff repair can dramatically increase the relative tension in the different sutures of the cuff repair. Study Design Controlled laboratory study. Methods In a cadaver model, a 4-suture supraspinatus repair was carried out with transosseous sutures. After the repair, the arm was placed in 12 different positions. The tension in each suture was monitored using individual load cells. Results When the arm was externally rotated relative to the plane of the scapula, the tension in the anterior suture was over 10 times that in the posterior suture (P <. 001). When the arm was internally rotated, the tension in the posterior suture was over 10 times that in the anterior suture (P <. 0005). When the arm was in neutral rotation, there was no significant difference in the suture tension. Conclusions This study is the first report of direct suture tension measurement after a model rotator cuff repair. In this model, 30° of either internal or external rotation of the arm in relation to the plane of the scapula created substantial imbalances in the tension between the most anterior and most posterior sutures of a supraspinatus repair, regardless of the position of abduction. Clinical Relevance Avoiding external rotation stretching during the healing of supraspinatus repairs may prevent tension overload in the critical anterior suture.

Electromyographic Activity in the Immobilized Shoulder Girdle Musculature During Ipsilateral Kinetic Chain Exercises

Smith J, Dahm DL, Kotajarvi BR, Boon AJ, Laskowski ER, Jacofsky DJ, Kaufman KR. Electromyographic activity in the immobilized shoulder girdle musculature during ipsilateral kinetic chain exercises. Objective To quantify the electromyographic activity in the shoulder girdle musculature during ipsilateral kinetic chain exercises performed in a shoulder immobilizer in asymptomatic men. Design Descriptive. Setting Motion analysis laboratory at a tertiary care center. Participants Five asymptomatic male volunteers, ages 24 to 32 years. Intervention Fine-wire (supraspinatus, infraspinatus, upper subscapularis) and surface (deltoids, trapezii, biceps, serratus anterior) electrodes recorded electromyographic activity from each muscle during a split-stance cross-body rotation (twisting to the opposite side at high, mid, and low levels), split stance attempted ipsilateral floor touch, and attempted overhead reach. All movements were initiated from the immobilized scapula and were tested with and without a combined step. Main Outcome Measure Mean peak normalized (percentage of maximum voluntary contraction [%MVC]) electromyographic activity of each muscle during each exercise. Results For all exercises, biceps and infraspinatus activity remained low (<10% MVC), whereas upper subscapularis activity was moderate to very high (29%−68% MVC). Supraspinatus activity was low (<20% MVC) for all motions except the attempted overhead reach (23% MVC). Serratus electromyographic activity was less than 20% of MVC for all motions and was most responsive to added stepping (23%−136% MVC without stepping vs 24%−199% MVC with stepping). Cross-body rotation at lower heights progressively increased serratus activity while decreasing supraspinatus, upper trapezius, and anterior deltoid activity. Conclusions Based on these electromyographic data, selected kinetic chain exercises could potentially be implemented during periods of shoulder immobilization. All exercises examined could potentially be safe after superior labral anteroposterior repair, but not after subscapularis repair. All exercises, with the exception of the attempted overhead reach, could potentially be safe after supraspinatus repair, with or without concomitant infraspinatus repair. Early activation of the serratus anterior could potentially be achieved by performing cross-body rotations, particularly at lower heights.