Does the critical shoulder angle decrease after acromioplasty? A systematic review and meta-analysis

Background Rotator cuff tears are one of the most common shoulder injuries in the older population. This study aimed to determine whether acromioplasty reliably decreases the critical shoulder angle (CSA) and describe any associated complications. Methods A systematic literature review was performed according to PRISMA guidelines using PubMed, EMBASE, Web of Science, and Cochrane Library Database. Two reviewers independently screened the titles and abstracts using prespecified criteria. Studies where the acromioplasty was performed as a surgical procedure were included. Patient characteristics and degree of CSA reduction were collected from each individual study. All statistical analyses were performed using Review Manager (RevMan) 5.4.1 software. A random-effects model was used for meta-analysis. Results A total of 9 studies involving 1236 patients were included in the meta-analysis. The age of patients ranged from 23 to 82 years. The follow-up period ranged from 12 to 30 months. Of the 9 studies, 8 (88.9%) were retrospective, 1 (11.1%) was prospective, 5 were comparative, and 4 were case series. The mean CSA was significantly reduced from 36.1° ± 4.6° to 33.7° ± 4.2 (p < 0.05). The meta-analysis showed an overall best estimate of the mean difference in pre- and postoperative CSA equal to 2.63° (95% confidence interval: 2.15, 3.11] (p < 0.00001). Conclusions Acromioplasty can significantly reduce CSA, notably in cases of high preoperative CSA. In addition, the effect of lateral acromioplasty on the CSA was more significant compared to anterolateral acromioplasty. Acromioplasty was not associated with complications during the short-term follow-up.

The Biomechanical and Histological Processes of Rerouting Biceps to Treat Chronic Irreparable Rotator Cuff Tears in a Rabbit Model

Background: Recently, the biceps was rerouted into a newly fabricated bicipital groove for in situ superior capsular reconstruction (SCR), resulting in promising time-zero cadaveric and clinical outcomes. However, no studies have determined the in vivo biomechanical and histological processes after the biceps is transposed to a nonanatomic position. Purpose: To explore the in vivo biomechanical and histological processes of the rerouting biceps tendon to treat chronic irreparable rotator cuff tears (IRCTs) in a rabbit model. Study Design: Controlled laboratory study. Methods: A total of 94 skeletally mature male rabbits were used to create a chronic IRCT model in the supraspinatus tendon. Then, the biceps rerouting procedures were performed in rabbits with chronic IRCT. Eighteen rabbits were sacrificed at 1, 3, 6, 9, and 12 weeks postoperatively for biomechanical testing, micro—computed tomography scanning, and histological analysis. The biomechanical and histological changes of intra- and extra-articular portions of the rerouting biceps were evaluated at each time point, with the contralateral native superior capsule (NSC) and the native biceps (NB) as controls, respectively. The morphology and bone formation of the fabricated bicipital grooves were evaluated, with native grooves as controls. Results: The intra-articular rerouting biceps tendon was progressively remodeled over time, displaying denser fibers and more mature collagen than those of the NSC, with gradual improvements in the tendon-to-bone healing interface from 6 to 12 weeks. Consequently, the failure load and stiffness of the intra-articular rerouting biceps portion increased with time and were significantly higher than those of the NSC from 9 weeks. Similarly, the extra-articular portion of the rerouting biceps progressively healed into a new bicipital groove, as demonstrated by a smaller tendon-to-bone interface from 6 to 12 weeks, resulting in greater failure load and stiffness at 9 and 12 weeks than those of the NB attachment. The newly fabricated bicipital groove showed similar morphology to that of the native groove with sufficient trabecular bone formed underneath. Conclusion: The rerouting biceps could progressively remodel and heal into the newly fabricated bicipital groove over time, resulting in greater biomechanical performances in intra- and extra-articular portions than the NSC and the NB attachment. Clinical Relevance: The biceps rerouting technique may be a feasible procedure to perform in situ SCR to treat IRCT in the future clinical practice; however, more clinical evidence is required.

Arthroscopic remplissage is safe and effective: clinical and magnetic resonance results at a minimum 3 years of follow-up

Background Large Hill–Sachs lesions are considered a risk factor for recurrence of instability after arthroscopic Bankart repair alone. The aim of this study was to demonstrate that remplissage is a safe procedure that effectively reduces the risk of recurrent dislocations without causing fatty degeneration of the infraspinatus at medium-term follow-up. Methods Patients who underwent arthroscopic Bankart repair and remplissage with a minimum 3 years of follow-up were included. Constant–Murley (CMS), American Shoulder and Elbow Surgeons (ASES), and Walch–Duplay scores were evaluated. Magnetic resonance imaging (MRI) was performed to detect the appearance of fatty infiltration inside the infraspinatus muscle, the percentage of the Hill–Sachs lesion filled by the tendon and its integration, and the onset of rotator cuff tears. Results Thirteen patients (14 shoulders) with a mean follow-up of 55.93 (± 18.16) months were enrolled. The Walch–Duplay score was 95.00 [87.25–100.00], with a return to sport rate of 100%. Both the CMS and the ASES indicated excellent results. The affected shoulders showed a statistically significant reduction in active external rotation both with the arm at the side (ER1) and with the arm at 90° of abduction (ER2) (p = 0.0005 and p = 0.0010, respectively). A reduction in infraspinatus isometric strength was found for both ER1 and ER2, but this reduction was only statistically relevant in ER2 (p = 0.0342). There was a traumatic recurrence of instability in two cases (14.28%). MRI evaluation demonstrated an absence of adipose infiltration in 50% of cases and only a minimal amount in the remaining 50%. In 12 cases (85.72%), the capsulotenodesis completely filled the lesion and good tendon–bone integration was observed. Conclusion Arthroscopic remplissage provided successful clinical outcomes without fatty infiltration of the infraspinatus and with good healing of the tissues. The low risk of recurrence was associated with an objective limitation on active external rotation, but this did not influence the patients' daily or sports activities. Level of evidence: Cohort study, level of evidence 3.

Fibro-adipogenesis in Injured Rotator Cuff Muscle

Purpose of Review Fibro-adipogenic progenitors were first characterized in 2010 and later found to contribute significantly to muscle regeneration and mediate degenerative changes in muscle following injury. These progenitors were also found to have an influence on the rotator cuff muscle’s response to chronic injury which is defined by fibrosis accompanied by massive fatty degeneration. The purpose of this review is to highlight progenitor cells, their contribution to fibro-adipogenesis in rotator cuff tissue, and the factors influencing fibro-adipogenesis in this tissue. Recent Findings Fibro-adipogenic progenitors are a key mediator of the fatty infiltration notably prevalent in rotator cuff injury. Relative to other muscle groups, the rotator cuff has relatively high rates of fibro-adipogenesis following massive chronic rotator cuff tears. This may be linked to the pre-injury density of fibro-adipogenic progenitors in muscle tissue affecting post-injury levels of fibro-adipogenesis. In addition, suprascapular nerve injury in rat models of rotator cuff tears has demonstrated worse, histologic, and biomechanical properties and lower healing rates of rotator cuff repairs. However, fatty infiltration in the rotator cuff following suprascapular nerve compression has been shown to be reversible following release of the nerve compression. Summary The fibro-adipogenic response to acute and chronic injury in rotator cuff tissue is determined by a complex array of factors including progenitor cell influence, transcriptional pathways, chronicity of the injury, anatomic location of injury, microenvironmental influences, and the severity of nerve involvement. Elucidating the complex interactions of these factors will provide potential targets for therapeutic intervention in vivo.

Early Efficacy Assessment of Arthroscopic Lower Trapezius Transfer With Tendon Autograft in the Management of Massive Irreparable Posterosuperior Rotator Cuff Tears

Objectives: To explore the indications and surgical techniques for arthroscopic lower trapezius transfer (LTT) with tendon autograft in managing massive irreparable posterosuperior rotator cuff tears (PSRCTs); to validate the feasibility, safety, and efficacy of this technique.Methods: This study retrospectively enrolled 23 patients with massive irreparable PSRCTs, admitted to and followed up by the Taizhou Hospital of Zhejiang province between July 2020 and April 2021, and treated with ipsilateral LTT and ipsilateral hamstring tendon autograft. The control group consisted of 23 patients with massive RCTs receiving conventional repair procedures within the same frame. Follow-up data at the preoperative visit, and postoperative month 3 were collected to assess the active range of motion, Constant–Murley Score (CMS),American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), University of California, Los Angeles (UCLA)shoulder score, visual analog scale (VAS)and the post-operative MRI results, all of which could provide a comprehensive postoperative early efficacy assessment.Results: Three months follow-up visits were completed for all patients, revealing improvements in all aspects compared to the preoperative state, with no complications, such as postoperative infection of surgical sites and nerve injuries of infection and nerve injury. The distribution of active shoulder range of motion of patients and function scores with two types of operation was as follow: angles of flexion and lifting (130.00° ± 31.55° vs. 90.78° ± 19.85°), abduction (123.26° ± 30.47°vs. 85.87° ± 18.74°), external rotation at side (101.74° ± 14.74° vs. 91.74° ± 11.92°), external rotation at 90° abduction (41.52° ± 21.97° vs. 24.57° ±12.60°), VAS (0.74± 0.81 vs. 1.87 ±0.87), CMS(56.3 ± 13.01 vs. 48.30 ± 8.38), UCLA shoulder score (24.04 ± 2.88 vs.20.96 ± 3.47), ASES (72.91 ± 9.99 vs.60.74 ± 8.84). Significantly better improvements were found in the study group on month 3.19 of 23 patients in the study group and 17 of 23 patients in the control group underwent MRI on the 3 months follow up. Retear was found in only one patient who had grade 4 subscapularis tendon injury, However, revision was not performed due to postoperative pain relief and functional improvement.Conclusion: Compared to conventional repair procedures, in the early postoperative period, LTT with tendon autograft could achieve better pain relief, more rapid motor functional recovery, and higher functional scores for massive irreparable PSRCTs.

Advanced Glycation End-products Are Associated With Limited Range of Motion of the Shoulder Joint Following Rotator Cuff Tears

Background: Most degenerative rotator cuff tears (RCTs) are associated with a limited range of motion (ROM) of the shoulder joint. Additionally, patients with diabetes mellitus (DM) show a higher frequency of limited ROM. Recently, advanced glycation end products (AGEs) of proteins have been observed to cause tissue fibrosis, primarily through abnormal collagen cross-linking and oxidative stress. In this study, we investigated the effect of AGEs on ROM limitation in the shoulder capsule and its relationship with DM.Methods: 16 patients (8 each in the DM and non-DM groups) who underwent arthroscopic surgery for RCT with limited shoulder ROM were included in this study. AGE-related pathologies in both groups were compared, and the relationship between AGE accumulation and shoulder joint ROM was evaluated. Shoulder capsule tissue was harvested and subjected to histological and in vitro evaluation. Results: The DM group displayed high levels of AGEs and reactive oxygen species (ROS), and reduced cell viability. There was a significant positive correlation between ROS expression, apoptosis, and preoperative hemoglobin A1c. ROS expression, apoptosis, and ROM of the shoulder joint showed a negative correlation. The NADPH oxidase (NOX) expression and collagen III/I ratio were significantly higher in the DM group than in the non-DM group.Conclusions: The DM group showed significant AGE deposition in the shoulder capsule. Additionally, there was a significant association between AGEs and ROM limitation. The oxidative stress induced by AGE deposition, which leads to fibrosis and local inflammation, might contribute to the limited ROM of the shoulder joint.

Recurrence in traumatic anterior shoulder dislocations increases the prevalence of Hill–Sachs and Bankart lesions: a systematic review and meta-analysis

Purpose The extent of shoulder instability and the indication for surgery may be determined by the prevalence or size of associated lesions. However, a varying prevalence is reported and the actual values are therefore unclear. In addition, it is unclear whether these lesions are present after the first dislocation and whether or not these lesions increase in size after recurrence. The aim of this systematic review was (1) to determine the prevalence of lesions associated with traumatic anterior shoulder dislocations, (2) to determine if the prevalence is higher following recurrent dislocations compared to first-time dislocations and (3) to determine if the prevalence is higher following complete dislocations compared to subluxations. Methods PubMed, EMBASE, Cochrane and Web of Science were searched. Studies examining shoulders after traumatic anterior dislocations during arthroscopy or with MRI/MRA or CT published after 1999 were included. A total of 22 studies (1920 shoulders) were included. Results The proportion of Hill–Sachs and Bankart lesions was higher in recurrent dislocations (85%; 66%) compared to first-time dislocations (71%; 59%) and this was statistically significant (P < 0.01; P = 0.05). No significant difference between recurrent and first-time dislocations was observed for SLAP lesions, rotator-cuff tears, bony Bankart lesions, HAGL lesions and ALPSA lesions. The proportion of Hill–Sachs lesions was significantly higher in complete dislocations (82%) compared to subluxations (54%; P < 0.01). Conclusion Higher proportions of Hill–Sachs and Bankart were observed in recurrent dislocations compared to first-time dislocations. No difference was observed for bony Bankart, HAGL, SLAP, rotator-cuff tear and ALPSA. Especially when a Hill–Sachs or Bankart is present after first-time dislocation, early surgical stabilization may need to be considered as other lesions may not be expected after recurrence and to limit lesion growth. However, results should be interpreted with caution due to substantial heterogeneity and large variance. Level of evidence IV.