Achieving tendon enthesis regeneration across length scales.

Surgical reattachment of tendon to bone is a clinical challenge, with unacceptably high retear rates in the early period after repair. A primary reason for these repeated tears is that the multiscale toughening mechanisms found at the healthy tendon enthesis are not regenerated during tendon-to-bone healing. The need for technologies to improve these outcomes is pressing, and the tissue engineering community has responded with many advances that hold promise for eventually regenerating the multiscale tissue interface that transfers loads between the two dissimilar materials, tendon, and bone. This review provides an assessment of the state of these approaches, with the aim of identifying a critical agenda for future progress.

The effectiveness of intravenous zoledronic acid in elderly patients with osteoporosis after rotator cuff repair: a retrospective study.

The aim of this study was to investigate the effect of zoledronic acid (ZA) on postoperative healing and functional rehabilitation in osteoporotic patients with rotator cuff (RC) injury. 96 Patients were divided into three groups according to bone mineral density and ZA use (Group A: normal BMD; Group B: osteoporosis and intravenous ZA use; Group C: osteoporosis, without ZA use). Radiologic, functional and Serological outcomes were evaluated 6 months after surgery. The functional scores in all groups exhibited significant improvement 6 months after surgery. Inter-group comparison showed that Constant Shoulder joint function Score (CSS) of group A not significantly differing from that of group B, the other indicators were significantly better than those of group B and C. There were no significant differences in shoulder forward flexion, abductive Range of Motion between group B and C. Other indicators of group B were significantly improved compared to group C. The retear rate in group C (30.3%, 10/33) was higher than group A (6.1%, 2/33) and group B (13.3%, 4/30). In conclusion, the application of ZA can significantly reduce the rate of RC retear in elderly patients with osteoporosis after surgery, which is significant for postoperative shoulder joint functional rehabilitation.

Influence of statin use on progression of postoperative fatty infiltration in the arthroscopic rotator cuff repair.

PURPOSE: The purpose of this study was to determine the influence of hyperlipidemia and statin (hydroxyl-methylglutaryl-coenzyme-A reductase inhibitors) use on fatty infiltration (FI) of the rotator cuff muscle after arthroscopic rotator cuff repair (ARCR). The presence or absence of statin use and type of statins used (type 1 naturally derived statins and type 2 synthetic statins) were examined. METHODS: This was a retrospective review of 620 cases (620 shoulders) who underwent arthroscopic rotator cuff repair. Total cholesterol (TC), low-density lipoprotein (LDL), triglycerides (TG) levels, and statin use were reviewed with the medical records. FI of the cuff muscles and repair integrity were assessed by MRI. A generalized linear model was used to analyze the progression of fatty infiltration. Repair integrity was determined according to the Sugaya classification, with types 4 and 5 as retears. RESULTS: The mean age was 66.9 years (272, females). The overall retear rate was 16.1%. There was no significant difference in retears between statin use and non-use with a trend toward higher retear rates in the type 2 statins. FI progressed postoperatively, and multivariate regression showed that type 2 statin use was a significant risk factor (p = 0.006). Other significant risk factor were large-to-massive tear (p = 0.02) and retear (p < .0001). CONCLUSIONS: The progression of FI after ARCR was observed. The new generation of strong statins (type 2 statins) was a significant risk factor for the progression of postoperative fatty infiltration, while neither serum lipid level (TC, LDL, and TG) was significant.

Outcomes of Total Shoulder Arthroplasty With and Without Prior Rotator Cuff Repair: A Systematic Review.

Background: The effect of prior rotator cuff repair (RCR) on clinical outcomes after total shoulder arthroplasty (TSA) is unclear. Purpose: To systematically review the literature to compare the outcomes of TSA in patients with and without prior RCR. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines by searching the PubMed, Cochrane Library, and Embase databases to identify studies comparing outcomes of TSA with and without prior RCR. The inclusion criteria were full-text studies that directly compared outcomes between patients undergoing anatomic or reverse TSA with and without prior RCR. A quality assessment was performed using the Modified Coleman Methodology Score (MCMS), and risk of bias assessment was performed using the Risk Of Bias In Non-randomized Studies-of Interventions (ROBINS-I) tool. A total of 1542 articles were identified for review based on initial database queries. Weighted means of quantifiable demographics and patient-reported outcomes were calculated for all included studies and compiled, in addition to the MCMS and ROBINS-I tool. Results: Twelve studies (10 level 3, 2 level 4) met inclusion criteria, including a total of 885 patients who underwent RCR before TSA (mean age, 68.2 years) and 2275 patients with no prior RCR (mean age, 70.0 years). Of all outcomes evaluated, patients with reverse TSA showed superior results in the no prior RCR group. Three reverse TSA studies found the no prior RCR group to have significantly higher postoperative American Shoulder and Elbow Surgeons scores when compared with the prior RCR group (P < .05). Multiple reverse TSA studies found the no prior RCR group to have significantly higher postoperative Simple Shoulder Test scores (P < .05) and significantly improved forward elevation (P < .05) when compared with the prior RCR group. Of all outcomes in anatomic TSA studies, only complication rate was different between groups, with 1 study finding a significantly lower complication rate in the no prior RCR group (P = .01). Conclusion: Patients undergoing reverse TSA without prior RCR can be expected to experience statistically better outcomes when compared with patients with prior RCR, while patients undergoing anatomic TSA can be expected to have similar outcomes regardless of prior RCR status.

Aponeurotic Expansion as a Cause for Rotator Cuff Tears but Full Joint Movements in Patients: Magnetic Resonance Arthrography Images of Aponeurotic Expansion and the Clinical Situation.

This case report presents the detailed clinical and radiological findings of a 63-year-old male patient who presented with right shoulder pain. Magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) revealed significant tears in most of the rotator cuff muscles. Despite these findings, the patient was able to perform full shoulder movements, suggesting that aponeurotic expansion may play a crucial role in this scenario. This case highlights important clinical findings that could lead to potential changes in shoulder surgery and rehabilitation approaches.

Associations between fatty infiltration of rotator cuff muscles and tear size or location of rotator cuff tendon.

Background: Fatty infiltration (FI) of rotator cuff muscles in patients with rotator cuff tears is an important imaging factor for determining surgical indications. However, the associations between FI grade and the size or location of adjacent rotator cuff tears are not well-known. This study aimed to primarily determine whether tear size and location, especially for the SSc tendon, are associated with FI of adjacent rotator cuff muscles. The secondary aim was to clarify which patient factors are associated with rotator cuff muscle FI in rotator cuff tear cases. Methods: This study examined 373 shoulders of 348 patients (264 males and 109 females; mean age of 62.8 years) who underwent arthroscopic rotator cuff surgery. The FI grades of the supraspinatus (SSP), infraspinatus (ISP), and subscapularis (SSc) muscles were assessed using preoperative magnetic resonance imaging (MRI) using the Goutallier classification modified by Fuchs. According to the preoperative MRI and intraoperative findings, the tear size of the posterior-superior rotator cuff (SSP-ISP) was classified using a modified six-grade scale of the Cofield classification, and that of the SSc tear was classified using a six-grade scale according to the Lafosse classification. Age at surgery, sex, body mass index (BMI), presence of diabetes mellitus (DM) or hyperlipidemia (HL), trauma history, and duration of symptoms were investigated. Results: The FI grades of the SSP, ISP, and SSc were significantly associated with the size of the tears in those muscles (all P < 0.01). Furthermore, the FI grades of the SSP and the ISP were significantly associated with SSc tear size (P < 0.01), and the FI grade of the SSc was significantly associated with SSP-ISP tear size (P < 0.01). Patient age at surgery was significantly associated with FI grade (P < 0.01), with significant progression of the FI grade with advancing age. However, there were no significant associations between the FI grade and sex, BMI, presence of DM or HL, trauma history, and duration of symptoms. Conclusions: The FI grade of each of the rotator cuff muscles is affected by not only the tear severity of the muscle concerned but also by the severity of any tear in the adjacent rotator cuff.

Irreparable Cuff Injuries: Treatment Options and Clinical Outcomes.

Rotator cuff tear is a common source of pain and disfunction in shoulder, with prevalence increasing with age. Nonsurgical treatment is adequate for many patients; however, for those for whom surgical treatment is indicated, rotator cuff repair provides reliable pain relief and good functional results. However, massive and irreparable tears due to tear size, tendon retraction, muscle atrophy, fatty infiltration are a significant challenge for surgeons. Whenever irreparable tears coexist with cartilage degeneration/arthritis (rotator cuff arthropathy), the indication of reverse shoulder arthroplasty is the golden standard. However, in young patients without arthritis, joint preserving procedures, from debridement to muscle transfers, are preferred. Choosing the most appropriate treatment is not quite established in literature, each treatment modality present particular indications, advantages and disadvantages.

Effect of polydeoxyribonucleotide and polynucleotide on rotator cuff healing and fatty infiltration in a diabetic rat model.

Failure rate after chronic rotator cuff repair is considerably high. Moreover, diabetes mellitus is known as a compromising factor of rotator cuff tear. The effect of Polydeoxyribonucleotide (PDRN) and polynucleotide (PN) on tendon healing and fatty infiltration is unclear as tissue regeneration activator in diabetic state. Therefore, a diabetic rat model with chronic rotator cuff tear was made for mechanical, histologic and blood tests. In the animal study using a diabetic rat cuff repair model, the administration of PDRN and PN increased the load to failure of repaired cuffs and improved tendon healing and decreased fatty infiltration. Also, the plasma levels of vascular endothelial growth factor and fibroblast growth factor were elevated in PDRN and PN administrated groups. We concluded that PDRN and PN appear to boost tendon recovery and reduce the presence of fatty infiltration following cuff repair in diabetic state. Also, PN showed a later onset and a longer duration than PDRN associated with the mean plasma growth factors.

The relationship between the shape of rotator cuff tears and shoulder anatomical parameters.

BACKGROUND: The aim of this study is to investigate the potential relationship between shoulder anatomical parameters and the shape of rotator cuff tears (L-shaped, U-shaped, and crescent-shaped). MATERIALS AND METHODS: The study included 160 (n:160) patients. Patients were divided into four groups: crescent type, u type and L type tears and control group. There were 40 cases in each group. The operated patients were divided into three groups based on the shape of the tears in arthroscopic images. Measurements of Critical Shoulder Angle (CSA), Greater Tuberosity Angle (GTA), Acromion Index (AI), Lateral Acromion Angle (LAA), and Humerus Footprint width (coronal width and sagittal width) were taken in each group and compared. RESULTS: Patients were divided into four different groups: Crescent type group (n:40), L type group (n:40), U type group (n:40) and control group (n:40). Upon assessing the coronal and sagittal width measurements, The mean coranal width measurement of the L-type tear group was 12.62 ± 0.29 mm, which was significantly higher than all other groups (p < 0.05). The mean sagittal width of the L-type tear group was 34.95 ± 0.29 mm, which was significantly higher than all other groups (p < 0.05). When the groups were evaluated based on GTA, CSA, and AI data, the mean GTA measurement of the L-type tear group was 73.03 ± 0.95 degrees, which was significantly higher than all other groups (p < 0.05). The mean CSA measurement of the L-type tear group was 34.77 ± 0.66 degrees, which was significantly higher than all other groups (p < 0.05). The mean AI measurement of the L-type tear group was 0.77 ± 0.02, which was significantly higher than all other groups (p < 0.05). When the groups were evaluated based on LAA data, the mean LAA measurement of the L-type tear group was 76.98 ± 1.04 degrees, which was significantly lower than all other groups (p < 0.05). CONCLUSION: In our study, especially in L-shaped tears, measurements of GTA, CSA, AI, LAA, coronal and sagittal width were found to be different compared to the control group. These results suggest that shoulder anatomy affects the mechanisms of rotator cuff tear formation and that these parameters play a more significant role in L-shaped tears.

The bioinductive collagen implant yields positive histological, clinical and MRI outcomes in the management of rotator cuff tears: A systematic review.

PURPOSE: The aim of this study is to report and discuss the outcomes of clinical, histological and animal studies exploring the application of bio-inductive collagen implants (BCIs) to partial and full-thickness rotator cuff tears (PT- and FT-RCTs) in addition to reporting on cost-related factors. METHODS: Review of literature was performed using the PRISMA guidelines. A systematic electronic literature search was conducted using the CENTRAL, CINAHL, Cochrane Library, EBSCOhost, EMBASE and Google Scholar bibliographic databases. Microsoft Excel was used to create tables onto which extracted data were recorded. Tables were organized based on the research statement formulated using the PICO approach. No statistical analysis was performed. RESULTS: Nine studies evaluated clinical and MRI outcomes of BCI augmentation for FT-RCTs, seven evaluated similar outcomes when applied to PT-RCTs, two additional studies were case reports and three studies assessed application to FT- and PT-RCTs without stratification of results, one of which also reported on histological data. Two studies reported on histological data alone, and finally, two reported on healthcare costs. BCI augmentation, alone and combined with rotator cuff repair (RCR), displays generally good histological, postoperative clinical and MRI outcomes for PT- and FT-RCT treatment. Recent economic analyses seem to be in favour of the use of this procedure, when selected and applied for appropriate patient populations. CONCLUSION: Several studies have shown promising results of BCI application to PT- and FT-RCTs, both concomitantly and independently from RCR. Investigations report promising histological characteristics, improved clinical outcomes, increased tendon thickness, reduced defect size and lower re-tear rates. LEVEL OF EVIDENCE: Level IV.

Characteristics of Traumatic Versus Atraumatic Rotator Cuff Tears in Patients Under 50 Years of Age.

BACKGROUND:  The prevalence of rotator cuff tears (RCTs) is known to be lower in younger patients compared to older patients. Recent studies in patients less than 50 years of age who sustain an RCT have focused on etiology, pathogenesis, and clinical outcomes following treatment. There are fewer studies that have focused on the demographics and clinical characteristics that may predispose this patient population to develop a tear. The purpose of this study is to evaluate the difference in risk factors for degenerative tears compared to traumatic tears in patients under 50 years of age. METHODS: This single-center retrospective study utilized an internal registry of patients who had RCT injuries identified by the International Classification of Diseases (ICD)-10 code M75.1x and confirmed by MRI between 2018 and 2023. Patients 50 years of age or younger were included and then classified into traumatic versus atraumatic RCT etiology groups. Demographics, tear characteristics, and clinical comorbidities were compared between the cohorts. Statistical analyses included a two-sided student's t-test, Wilcoxon rank-sum test, Chi-square test, and Fisher's exact test. RESULTS: A total of 177 patients under 50 years of age were identified. There was a higher prevalence of traumatic tears (59.9% vs. 40.1%; p = 0.008), the majority of whom identified as male (75.5% vs. 49.3%, p<0.001) when compared to the atraumatic cohort. Full-thickness tears were more likely to be traumatic (p = 0.04) and seen in patients insured by workers' compensation (p = 0.05). There was no significant difference in the age or preoperative comorbidities between the two groups. CONCLUSIONS: Our study reveals a higher incidence of traumatic RCTs in a younger patient group. Sex, severity of tear, and workers' compensation were found to differ between traumatic and atraumatic cohorts. Further research is required to understand the interplay of these factors in younger patients' tear risk.

Muscle Advancement During Arthroscopic Rotator Cuff Repair as a Treatment Option for Irreparable Rotator Cuff Tears.

Background: The management of irreparable rotator cuff tears presents a surgical dilemma. However, supraspinatus muscle advancement (MA) could be used to convert irreparable to reparable tears without requiring a graft. Purpose: To compare the outcomes of patients with an irreparable tear who underwent rotator cuff repair with MA with those with a reparable large to massive cuff tear who underwent rotator cuff repair. Study Design: Cohort study; Level of evidence, 3. Methods: We enrolled 62 patients who underwent rotator cuff repair for a large to massive tear between January 2020 and May 2022. Among them, 29 patients underwent an MA procedure due to an inability to repair despite releases (MA group), whereas the other 33 patients did not require the procedure (NMA group). At 1 year postoperatively, follow-up assessments including magnetic resonance imaging were performed to evaluate group outcomes. Results: Despite there being more revision surgery cases and a poorer potential for cuff healing in the MA group, the retear rates in the MA and NMA groups were similar (31.0% vs 21.2%, respectively; P = .401), as were clinical outcomes, including the visual analog scale for pain (2.9 vs 1.9; P = .076), University of California, Los Angeles (27.0 vs 29.1; P = .185), Constant (70.1 vs 74.9; P = .063), and American Shoulder and Elbow Surgeons (74.5 vs 81.8; P = .168) scores. Postoperative muscle power during forward elevation was weaker in the MA group than in the NMA group (35.1 vs 45.8 N; P = .052), but external rotation power was comparable (49.3 vs 59.0 N; P = .121). Progress in fatty degeneration of the supraspinatus was not significantly different in the 2 groups (P = .43), although the MA group showed a nonsignificant decrease in supraspinatus atrophy (P = .092) due to the lateral shift produced by the procedure. Conclusion: The MA procedure for irreparable tears produced outcomes comparable with reparable tears, offering a valuable perspective on the efficiency of the procedure. The comparable but relatively high retear rates emphasize the need for further studies to compare with other treatment options for irreparable tears.

Association of Preoperative Shoulder Osteoarthritis Severity Score With Change in American Shoulder and Elbow Surgeons Score at 2 Years After Rotator Cuff Repair.

Background: The impact of early glenohumeral osteoarthritis (GHOA) on clinical outcomes after rotator cuff repair (RCR) remains unclear. The magnetic resonance imaging (MRI)-based Shoulder Osteoarthritis Severity (SOAS) score is a comprehensive approach to quantifying glenohumeral degeneration. Purpose: To investigate the association between SOAS scores and changes in American Shoulder and Elbow Surgeons (ASES) scores in patients who underwent RCR. Study Design: Cohort study; Level of evidence, 3. Methods: Two reviewers independently analyzed the preoperative MRI scans of 116 shoulders and assigned SOAS scores. Spearman correlation was used to calculate the association of mean SOAS scores with patient demographic characteristics and change in ASES scores over the 2-year follow-up period (ΔASES). Multivariate regression analysis was performed between the independent variables of patient age, sex, body mass index, and significant SOAS score components as determined by univariate analysis, with the dependent variable being ΔASES. Significance was defined as P < .05 for univariate analysis and P < .0125 after application of the Bonferroni correction for multivariate analysis. Results: The mean ASES scores were 55.8 ± 18.6 preoperatively and 92.1 ± 12.1 at 2 years postoperatively. The mean preoperative SOAS score was 15.2 ± 7.1. On univariate analysis, the total SOAS score was positively correlated with patient age (r S = 0.41; P < .001), whereas ΔASES was negatively correlated with patient age (r S = -0.27; P = .0032). Increasing SOAS subscores for supraspinatus/infraspinatus tear size (r S = -0.28; P = .024), tendon retraction (r S = -0.23; P = .015), muscle atrophy (r S = -0.20; P = .034), paralabral ganglia (r S = -0.23; P = .015), and cartilage degeneration (r S = -0.21; P = .024) were negatively correlated with ΔASES. A negative correlation was found between increasing total SOAS score and ΔASES (r S = -0.22; P = .016). On multivariate analysis, increasing supraspinatus/infraspinatus tear size was significantly and negatively correlated with ΔASES (ß = -3.3; P = .010). Conclusion: Increasing the total SOAS score was predictive of less improvement in ASES scores at 2 years postoperatively. On univariate analysis, SOAS subscores with the strongest negative correlations with ΔASES scores included tear size, muscle atrophy, tendon retraction, paralabral ganglia, and cartilage wear. On multivariate analysis, only tear size was significantly associated with a lower change in the ASES score.

A modified arthroscopic en masse suture bridge repair is effective for delaminated rotator cuff tears.

PURPOSE: This study aimed to clarify the characteristics of delaminated rotator cuff tears (RCTs) and evaluate the clinical outcomes of a modified arthroscopic en masse suture bridge repair for delaminated RCTs. METHODS: Patients with full-thickness RCTs, who underwent arthroscopic suture bridge repair with a minimum 2-year follow-up, were retrospectively reviewed. Patients were categorized into two groups based on the presence of delamination. Delaminated RCTs were treated using a modified en masse suture bridge technique, while nondelaminated RCTs received a conventional suture bridge technique. Preoperative and postoperative Constant scores and American Shoulder and Elbow Surgeons (ASES) scores were determined to evaluate clinical outcomes. Postoperative magnetic resonance imaging (MRI) was carried out to identify the integrity and retear of the repaired rotator cuff. RESULTS: A total of 172 patients were included in our study cohort, in which 67 (39%) delaminated RCTs were confirmed intraoperatively. The prevalence of delamination was significantly higher in large tears (53/102, 52%) compared to medium tears (14/70, 20%) (p < 0.001). No significant differences in age (n.s.) or gender (n.s.) were observed between the two groups. Both groups showed significant improvements in Constant and ASES scores postoperatively (both p < 0.001), with no significant differences between the groups (n.s.). The retear rates were 2/67 (3.0%) in the delamination group and 3/105 (2.9%) in the nondelamination group, showing no significant difference (n.s.). CONCLUSIONS: The modified arthroscopic en masse suture bridge technique was effective for repairing delaminated RCTs, yielding favourable clinical outcomes comparable to those of nondelaminated tears. LEVEL OF EVIDENCE: Level IV.

Humeral rotation osteotomy is not associated with glenohumeral and scapulohumeral decentering at long-term follow-up.

BACKGROUND: Weber rotational osteotomy which increases humeral retrotorsion in patients with anterior shoulder instability has become unpopular because of recurrence of instability and high rates of early onset OA. However, the wear pattern in patients after rotational osteotomy remains unknown. The aim of this study was to determine the influence of surgically increased humerus retrotorsion on glenohumeral and scapulohumeral centering in a long-term follow-up. METHODS: The data of 18 shoulders in 18 patients diagnosed with a unilateral chronic recurrent anterior shoulder instability treated with an internal rotation subcapital humerus osteotomy between 1984 and 1990 were drawn from a previously published cohort and enrolled in the study. All patients had available bilateral CT scans performed after a mean follow-up of 14 (12-18) years. On these CT scans a comparison of the operated and the contralateral healthy side with regards to humerus torsion, glenoid version, glenoid offset, glenohumeral and scapulohumeral subluxation indices, rotator cuff action lines and osteoarthritic changes (OA) was performed. RESULTS: The analysis of follow-up CT scans revealed a significantly higher mean humeral retrotorsion in the operated side compared to healthy side (41.6° ± 14.0° vs. 20.7°±8.2°, p<0.001). No differences were found in terms of glenohumeral subluxation index (0.50 ± 0.08 vs 0.51 ± 0.03, p = 0.259), scapulohumeral subluxation index (0.53 ± 0.09 vs 0.54 ± 0.03, p = 0.283), glenoid version (- 3.9° ± 4.6 vs - 4.1° ± 3.7, p = 0.424), glenoid offset (4.0 mm ± 2.8 vs 4.0 mm ± 1.3, p = 0.484), infraspinatus action lines (102.5° ± 4.7 vs 101.2° ± 2.1, p = 0.116) , subscapularis action lines (74.0° ± 6.0 vs 73.1° ± 2.3, p = 0.260) and resultant rotator cuff action lines (87.8° ± 4.9 vs 87.0° ± 1.8, p = 0.231) between operated and healthy shoulders. Osteoarthritic changes were observed in all operated shoulders and in 13 of 18 healthy shoulders. The OA Grade was mild in 5 patients, moderate in 11 and severe in 2 cases for operated shoulders and mild in 13 healthy shoulders at the last follow-up. CONCLUSION: The surgical increase of humeral retrotorsion by 20-30° did not affect glenohumeral and scapulohumeral centering in patients with a Weber rotational osteotomy after a long-term follow-up compared to the healthy side. While a high degree of early onset OA was observed it remains unclear whether the cause is the surgical interventions performed or the joint instability itself.

Rebound pain after arthroscopic cuff repair with interscalene brachial plexus block anesthesia is reduced by surgeon administered multimodal shoulder injections: A prospective randomized controlled trial.

PURPOSE: To compare the effects of additional multimodal shoulder injections on postoperative rebound pain in patients undergoing arthroscopic rotator cuff repair (ASRCR) under interscalene brachial plexus block (ISBPB) anesthesia. METHODS: A single-blind randomized controlled trial was conducted with 67 patients between April 2023 and December 2023. Patients undergoing ASRCR got an ISBPB anesthesia, not general anesthesia, were included with a minimum follow-up period of 48 h. The injection group received 40 mL of 0.75% ropivacaine, 20 mg morphine, 1:200,000 epinephrine, and saline solution, totaling 100 mL. Following surgery, the injection was administered to the subacromial space (50 ml) with blind suprascapular nerve block (25 ml) and blind axillary nerve block (25 ml). Controls received 100 mL of saline solution. Intravenous patient-controlled analgesia (IV-PCA) was used as adjuvant analgesia for all patients. The primary outcome was evaluated using the visual analog scale (VAS) pain score at 12 h after surgery, with secondary outcomes of the incidence of rebound pain and VAS pain scores at 0, 2, 4, 8, 24, 36, and 48 h postoperatively. Fentanyl in IV-PCA and rescue analgesic amounts, complications, and satisfaction were recorded. RESULTS: Sixty-seven patients (32 in the injection group, 35 in the control group) with a mean age of 61.1±9.0 years were included. The primary outcome assessment, VAS pain score at 12 h, significantly favored the injection group (2.7±0.93 vs. 4.1±1.70, p<0.001). The incidence of rebound pain was 18.8% and 65.7% in the injection and control groups, respectively (18.8% vs 65.7%, p<0.001). The injection group reported better VAS pain scores at 24, 36, and 48 h, and lower fentanyl use over the 48 h postoperative period (p=0.014). The use of rescue analgesics was similar between groups and no complications were associated with multimodal shoulder injections. Satisfaction levels were similar in both groups. CONCLUSION: The present study found that multimodal shoulder injections during ASRCR under ISBPB anesthesia significantly lowered VAS pain scores at 12 hours postoperatively and reduced the incidence of rebound pain compared to the control group. Pain levels were consistently lower from 12 to 48 hours postoperatively. Additionally, the injection group had reduced opioid consumption within the first 48 hours postoperatively, with no complications observed. LEVEL OF EVIDENCE: Level I, randomized controlled trial.

Supraspinatus Tendon Reconstruction Versus the Bridging Technique in a Rat Model: Histological, Biomechanical, and Functional Outcomes.

BACKGROUND: Massive irreparable rotator cuff tears (MIRCTs) are among the most challenging shoulder conditions to treat surgically. Supraspinatus tendon reconstruction (STR) is a recently introduced technique for MIRCTs based on fascia lata-muscle interface healing, which completely differs from the classic bridging technique with fascia lata-tendon interface healing. However, histological and biomechanical comparisons of the fascia-muscle and fascia-tendon interfaces have not been performed. PURPOSE: To investigate the histological and biomechanical healing of the fascia-bone interface and fascia-muscle interface after chronic MIRCTs in a rat model using different surgical methods. STUDY DESIGN: Controlled laboratory study. METHODS: The authors established a chronic MIRCT model in the right shoulder of rats and then repaired it using the STR or bridging repair technique. Evaluations were performed at 2, 4, 8, and 12 weeks, including histological, imaging, biomechanical, and functional analyses. RESULTS: Both techniques resulted in good fascia-bone interface healing based on the histological results. The STR group had significantly more cartilage formation at 8 and 12 weeks and higher Modified Tendon Maturity Score after 12 weeks at the fascia-bone interface compared with the bridging repair group and formed the typical 4-layered structure. Collagen fibers in the fascia-muscle and fascia-tendon interfaces exhibited normal muscle-tendon interface characteristics at 12 weeks. However, the STR group had more improvement in fatty infiltration compared with the bridging repair group. The ultimate failure load and stiffness did not differ between the STR and bridging repair groups 4 weeks postoperatively in both the fascia-bone interface and supraspinatus muscle-fascia-bone integrity. Movement distance and grasp time were significantly longer in the STR group than in the bridging repair group at 12 weeks and attached the level in the normal control groups. CONCLUSION: These results suggest that the fascia-muscle interface from the STR technique is histologically and functionally better than the fascia-tendon interface. Moreover, this study provides a theoretical basis for the clinical use of the STR technique. CLINICAL RELEVANCE: The fascia-muscle interface and fascia-tendon interface were the key points of the STR and bridging techniques, respectively. The fascia-muscle interface is histologically and functionally superior to the bridging technique, and the STR technique might be a better choice for the treatment of MIRCTs.

Does Surgical Intervention Alter the Natural History of Degenerative Rotator Cuff Tears? Comparative Analysis from a Prospective Longitudinal Study.

INTRODUCTION: The natural history of rotator cuff tears often involves progressive pain development, tear enlargement, and advancing muscle fatty degeneration. Both surgery and conservative management have proven to be effective treatments. Our study purpose was to compare the short to mid-term effects of rotator cuff repair on shoulder function, progression of tear size, and muscle degeneration compared to controls with asymptomatic tears that developed pain and were managed nonoperatively. METHODS: This comparative study consists of two separate longitudinal study arms. The control group consisted of asymptomatic degenerative cuff tears followed until pain development and then managed nonoperatively with continued surveillance. The surgical group consisted of subjects with degenerative tears that failed nonoperative treatment and underwent surgical intervention with a minimum of 2 years follow-up. Outcomes included VAS pain, ASES, AROM, strength, and ultrasonography. RESULTS: There were 83 controls and 65 surgical shoulders. The surgical group was younger at enrollment (58.9±5.3 yr vs. 61.2±7.8 yr, p=0.04). The median follow-up for control subjects after pain development was 5.1 years (IQR 3.6) and the median postoperative follow-up for the surgical group was 3.0 years (IQR 0.2). Baseline tear widths (median 14 mm, IQR 9 vs. 13 mm, IQR 8; p=0.45) and tear lengths (median 14 mm, IQR 13 vs. median 11 mm, IQR 8; p=0.06) were similar between the surgical group and controls. There were no differences in the baseline prevalence of fatty degeneration of the supraspinatus or infraspinatus muscles between groups (p=0.43 and p=0.58, respectively). At final follow-up, the surgical group demonstrated significantly lower VAS pain (0 [IQR 2] vs. 3.5 [IQR 4], p=0.0002), higher composite ASES (95 [IQR 13] vs. 65.8 [IQR 32], p=0.0002) and ADL scores (29 [IQR 4] vs. 22 [IQR 8], p=0.0002), greater abduction strength (69.6 N [SD 29] vs. 35.9 N [SD 29], p=0.0002), greater active forward elevation (155˚ [SD 8] vs. 142˚ [SD 28], p=0.002), greater active external rotation in abduction (mean 98.5˚, SD 12 vs. mean 78.2˚, SD 20; p=0.0002) compared to controls. Additionally, the prevalence of fatty muscle degeneration was lower in the surgical group for the supraspinatus and infraspinatus (25% vs. 41%, p=0.05; 17% vs. 34%, p=0.03; respectively). CONCLUSION: This prospective longitudinal study comparing a surgical cohort undergoing rotator cuff repair with a control group treated nonoperatively supports the notion that surgical intervention has the potential to alter the early natural history of degenerative rotator cuff disease. Patients in the surgical group demonstrated clinically relevant differences in pain and functional outcomes. Surgical intervention was protective against progressive muscle degeneration compared to nonoperative treatment.

Biomechanical and histological evaluation of aspirin in rotator cuff tear rat model.

Background: Aspirin is a representative non-steroidal anti-inflammatory drug (NSAIDs) and has been commonly used for the treatment of tendinopathy in clinical practice. In this study, we aimed to evaluate the biomechanical and histological healing effects of aspirin on the healing of the tendon-to-bone interface after rotator cuff tear repair. Methods: A total of 20 male Sprague-Dawley rats were randomly divided into two groups of 10 rats each. Group-C performed repaironly, and group-aspirin treated with aspirin after tendon repair. Group-aspirin rat were intraperitoneally injected with aspirin at 10 mg/kg every 24 h for 7 days. Eight weeks after surgery, the left shoulder of each rat was used for histological analysis and the right shoulder for biomechanical analysis. Results: In the biomechanical analysis, there was no significant difference in load-to-failure (group-C: 0.61 ± 0.32 N, group-aspirin: 0.74 ± 0.91 N; p = .697) and ultimate stress (group-C: 0.05 ± 0.01 MPa, group-aspirin: 0.29 ± 0.43 MPa; p = .095). For the elongation (group-C: 222.62 ± 57.98%, group-aspirin: 194.75 ± 75.16%; p = .028), group-aspirin confirmed a lower elongation level than group-C. In the histological evaluation, the Bonar score confirmed significant differences in collagen fiber density (group-C: 1.60 ± 0.52, group-aspirin: 2.60 ± 0.52, p = .001) and vascularity (group-C: 1.00 ± 0.47, group-aspirin: 2.20 ± 0.63, p = .001) between the groups. Conclusions: Aspirin injection after rotator cuff tear repair may enhance the healing effect during the early remodeling phase of tendon healing.

Three-Dimensional Morphological Analysis of the Suprascapular Notch in Patients with Arthroscopic Rotator Cuff Repair.

Background: The morphology of the suprascapular notch (SSN) and the ossification of the superior transverse suprascapular ligament (STSL) are risk factors for injury of the suprascapular nerve (SN) during arthroscopic shoulder procedures. The purpose of the current study was to compare preoperative clinical and radiologic characteristics between patients with and without STSL ossification and to evaluate SSN morphology in patients who underwent arthroscopic rotator cuff repair using a 3-dimensional (3D) reconstructed model. Methods: Patients who underwent arthroscopic rotator cuff repair and were given a computed tomography (CT) scan from March 2018 to August 2019 were included in this study. Patients were divided into 2 groups: those without STSL ossification (group I) and those with STSL ossification (group II). Tear size of the rotator cuff and fatty infiltration of rotator cuff muscles were assessed in preoperative magnetic resonance imaging. The morphology of the SSN was classified following Rengachary's classification. The transverse and vertical diameters of the SSN and the distances from anatomical landmarks to the STSL were measured. All measurements were completed using a 3D CT reconstructed scapula model. Results: A total of 200 patients were included in this study. One hundred seventy-eight patients (89.0%) without STSL ossification were included in group I, and 22 patients (11.0%) with STSL ossification were included in group II. Group II showed a significantly advanced age (61.0 ± 7.4 vs. 71.0 ± 7.3 years, p < 0.001) and a shorter transverse diameter of SSN (10.7 ± 3.1 mm vs. 6.1 ± 3.7 mm, p < 0.001) than group I. In the logistic regression analysis, age was an independent prognostic factor for STSL ossification (odds ratio, 1.201; 95% confidence interval, 1.112-1.296; p < 0.001). Patients in type VI showed significantly shorter transverse diameters than other types (p < 0.001). The patient with type I showed a significantly shorter distance from the articular surface of the glenoid to the SSN than those with other types (p < 0.001). Conclusions: In the 3D morphological analysis, age was the independent factor associated with STSL ossification in patients who underwent arthroscopic rotator cuff repair. Type VI showed significantly shorter transverse diameters than other types. Type I showed a significantly shorter distance from the articular surface of the glenoid to the SSN than other types.