The Fate of the Shoulder Post Rotator Cuff Repair: Biomechanical Properties of the Supraspinatus Tendon and Surrounding Structures.

The study aimed to describe the changes in biomechanical properties of the supraspinatus tendon, deltoid muscle, and humeral head post arthroscopic rotator cuff repair using shear wave elastography. Shear wave velocity of the tendon, deltoid, and humeral head of 48 patients was measured at predetermined sites at 1 week, 6 weeks, 12 weeks, 6 months, and 12 months post repair. One-way ANOVA with Tukey's correction and Spearman's correlation were performed. Mean±SEM healing tendon stiffness, adjacent to tendon footprint, increased from 1 week (6.2±0.2 m/s) to 6 months (7.5±0.3 m/s) and 12 months (7.8±0.3 m/s) (P<0.001). Mean±SEM deltoid muscle stiffness was higher at 12 months (4.1±0.2 m/s) compared to 1 week (3.4±0.1 m/s) and 12 weeks (3.5±0.1 m/s) (P<0.05). Humeral head stiffness did not change. Following arthroscopic rotator cuff repair, supraspinatus tendon stiffness increased in a curvilinear fashion over 6 months. From 6 months, deltoid muscle stiffness increased, corresponding to when patients were instructed to return to normal activities.

First atroposelective Chan-Lam coupling for the synthesis of C-N linked biaryls.

The first atroposelective Chan-Lam coupling for the synthesis of C-N axial enantiomers is reported with good yields and ee. MnO2 additive is crucial for the success of the coupling. The longstanding problem of the lack of enantioselective synthesis to make chiral C-N linked atropisomers is solved.

An assessment of factors associated with early postoperative stiffness in arthroscopic rotator cuff repair.

BACKGROUND: Postoperative stiffness affects up to 20% of patients following arthroscopic rotator cuff repair. Recent evidence indicates that early postoperative stiffness may associated with lower retear rates. This study aimed to identify the independent predictors of early postoperative stiffness. METHODS: A retrospective cohort study of 1526 rotator cuff repairs was performed. Range of motion at 6-week postop was used to identify stiff patients. Stiffness was defined as external rotation <27.5o or forward flexion <145o . Multiple logistic regression analysis was used to identify the independent predictors of 6-week stiffness. RESULTS: The independent predictors for external rotation stiffness at 6-week postop were more recent cases (Wald = 60), restricted preoperative external rotation (Wald = 36), younger age (Wald = 21) and poorer surgeon-ranked tissue quality (Wald = 15). The independent predictors for forward flexion stiffness were more recent cases (Wald = 101), restricted preoperative forward flexion (Wald = 16) and external rotation (Wald = 13) and female patients (Wald = 12). All patients that developed early postoperative stiffness had recovered range of motion by 6 months to preoperative levels (P < 0.0001). A significantly greater proportion of younger patients (40-49) developed postoperative stiffness when compared to older patients aged 50-59 (P < 0.0062), 70-79 (P < 0.0126) and 80-89 (P < 0.004). Patients that retore had significantly greater average 6-week postoperative range of motion. CONCLUSIONS: Patients earlier in the study were found to have greater postoperative range of motion, which coincided with a more aggressive rehabilitation program with less immobilization. Thus, the data supports the hypothesis that a temporary period of shoulder stiffness facilitates tendon repair and ultimately a better outcome post rotator cuff repair.

Left bundle branch area pacing for heart failure patients requiring cardiac resynchronization therapy: A meta-analysis.

INTRODUCTION: Left bundle branch area pacing (LBBP) is a novel conduction system pacing method to achieve effective physiological pacing and an alternative to cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) for patients with heart failure with reduced ejection fraction (HFrEF). We conduted this meta-analysis and systemic review to review current data comparing BVP and LBBP in patients with HFrEF and indications for CRT. METHODS: We searched PubMed/Medline, Web of Science, and Cochrane Library from the inception of the database to November 2022. All studies that compared LBBP with BVP in patients with HFrEF and indications for CRT were included. Two reviewers performed study selection, data abstraction, and risk of bias assessment. We calculated risk ratios (RRs) with the Mantel-Haenszel method and mean difference (MD) with inverse variance using random effect models. We assessed heterogeneity using the I2 index, with I2 > 50% indicating significant heterogeneity. RESULTS: Ten studies (9 observational studies and 1 randomized controlled trial; 616 patients; 15 centers) published between 2020 and 2022 were included. We observed a shorter fluoroscopy time (MD: 9.68, 95% confidence interval [CI]: 4.49-14.87, I2 = 95%, p < .01, minutes) as well as a shorter procedural time (MD 33.68, 95% CI: 17.80-49.55, I2 = 73%, p < .01, minutes) during the implantation of LBBP CRT compared to conventional BVP CRT. LBBP was shown to have a greater reduction in QRS duration (MD 25.13, 95% CI: 20.06-30.20, I2 = 51%, p < .01, milliseconds), a greater left ventricular ejection fraction improvement (MD: 5.80, 95% CI: 4.81-6.78, I2 = 0%, p < .01, percentage), and a greater left ventricular end-diastolic diameter reduction (MD: 2.11, 95% CI: 0.12-4.10, I2 = 18%, p = .04, millimeter). There was a greater improvement in New York Heart Association function class with LBBP (MD: 0.37, 95% CI: 0.05-0.68, I2 = 61%, p = .02). LBBP was also associated with a lower risk of a composite of heart failure hospitalizations (HFH) and all-cause mortality (RR: 0.48, 95% CI: 0.25-0.90, I2 = 0%, p = .02) driven by reduced HFH (RR: 0.39, 95% CI: 0.19-0.82, I2 = 0%, p = .01). However, all-cause mortality rates were low in both groups (1.52% vs. 1.13%) and similar (RR: 0.98, 95% CI: 0.21-4.68, I2 = 0%, p = .87). CONCLUSION: This meta-analysis of primarily nonrandomized studies suggests that LBBP is associated with a greater improvement in left ventricular systolic function and a lower rate of HFH compared to BVP. There was uniformity of these findings in all of the included studies. However, it would be premature to conclude based solely on the current meta-analysis alone, given the limitations stated. Dedicated, well-designed, randomized controlled trials and observational studies are needed to elucidate better the comparative long-term efficacy and safety of LBBP CRT versus BIV CRT.

Developing the supraparticle technology for round window-mediated drug administration into the cochlea.

The semi-permeable round window membrane (RWM) is the gateway to the cochlea. Although the RWM is considered a minimally invasive and clinically accepted route for localised drug delivery to the cochlea, overcoming this barrier is challenging, hindering development of effective therapies for hearing loss. Neurotrophin 3 (NT3) is an emerging treatment option for hearing loss, but its therapeutic effect relies on sustained delivery across the RWM into the cochlea. Silica supraparticles (SPs) are drug delivery carriers capable of providing long-term NT3 delivery, when injected directly into the guinea pig cochlea. However, for clinical translation, a RWM delivery approach is desirable. Here, we aimed to test approaches to improve the longevity and biodistribution of NT3 inside the cochlea after RWM implantation of SPs in guinea pigs and cats. Three approaches were tested (i) coating the SPs to slow drug release (ii) improving the retention of SPs on the RWM using a clinically approved gel formulation and (iii) permeabilising the RWM with hyaluronic acid. A radioactive tracer (iodine 125: 125I) tagged to NT3 (125I NT3) was loaded into the SPs to characterise drug pharmacokinetics in vitro and in vivo. The neurotrophin-loaded SPs were coated using a chitosan and alginate layer-by-layer coating strategy, named as '(Chi/Alg)SPs', to promote long term drug release. The guinea pigs were implanted with 5× 125I NT3 loaded (Chi/Alg) SPs on the RWM, while cats were implanted with 30× (Chi/Alg) SPs. A cohort of animals were also implanted with SPs (controls). We found that the NT3 loaded (Chi/Alg)SPs exhibited a more linear release profile compared to NT3 loaded SPs alone. The 125I NT3 loaded (Chi/Alg)SPs in fibrin sealant had efficient drug loading (~5 µg of NT3 loaded per SP that weights ~50 µg) and elution capacities (~49% over one month) in vitro. Compared to the SPs in fibrin sealant, the (Chi/Alg)SPs in fibrin sealant had a significantly slower 125I NT3 drug release profile over the first 7 days in vitro (~12% for (Chi/Alg) SPs in fibrin sealant vs ~43% for SPs in fibrin sealant). One-month post-implantation of (Chi/Alg) SPs, gamma count measurements revealed an average of 0.3 µg NT3 remained in the guinea pig cochlea, while for the cat, 1.3 µg remained. Histological analysis of cochlear tissue revealed presence of a 125I NT3 signal localised in the basilar membrane of the lower basal turn in some cochleae after 4 weeks in guinea pigs and 8 weeks in cats. Comparatively, and in contrast to the in vitro release data, implantation of the SPs presented better NT3 retention and distribution inside the cochlea in both the guinea pigs and cats. No significant difference in drug entry was observed upon acute treatment of the RWM with hyaluronic acid. Collectively, our findings indicate that SPs and (Chi/Alg)SPs can facilitate drug transfer across the RWM, with detectable levels inside the cat cochlea even after 8 weeks with the intracochlear approach. This is the first study to examine neurotrophin pharmacokinetics in the cochlea for such an extended period of times in these two animal species. Whilst promising, we note that outcomes between animals were variable, and opposing results were found between in vitro and in vivo release studies. These findings have important clinical ramifications, emphasising the need to understand the physical properties and mechanics of this complex barrier in parallel with the development of therapies for hearing loss.

Identification of novel tetrahydroquinoxaline derived phenyl ureas as modulators of the hepatitis B virus nucleocapsid assembly.

A key step of hepatitis B virus (HBV) replication is the selective packaging of pregenomic RNA (pgRNA) by core protein (Cp) dimers, forming a nucleocapsid where the reverse transcriptional viral DNA replication takes place. One approach in the development of new anti-HBV drugs is to disrupt the assembly of HBV nucleocapsids by misdirecting Cp dimers to assemble morphologically normal capsids devoid of pgRNA. In this study, we built upon our previous discovery of benzamide-derived HBV capsid assembly modulators by exploring fused bicyclic scaffolds with an exocyclic amide that is ß, γ to the fused ring, and identified 1,2,3,4-tetrahydroquinoxaline derived phenyl ureas as a novel scaffold. Structure-activity relationship studies showed that a favorable hydrophobic substitution can be tolerated at the 2-position of the 1,2,3,4-tetrahydroquinoxaline core, and the resulting compound 88 demonstrated comparable or improved antiviral potencies in mouse and human hepatocyte-derived HBV-replicating cell lines compared to our previously reported benzamide compound, 38017 (8). In addition, a novel bis-urea series based on 1,2,3,4-tetrahydroquinoxaline was also found to inhibit HBV DNA replication with sub-micromolar EC50 values. The mode of action of these compounds is consistent with specific inhibition of pgRNA encapsidation into nucleocapsids in hepatocytes.

Man vs. machine: surgeon vs. elastography assessment of the quality of the rotator cuff.

Background: The most common complication of arthroscopic rotator cuff repair is retear, which is more common in larger tears and older patients. We hypothesized that the quality of the torn tendon is important in protecting against retear. Surgeons have traditionally assessed the quality of repaired tendons with a four-point Likert scale. Shear Wave Elastography Ultrasound (SWEUS) is a recent technological advancement that can quantify soft-tissue stiffness. This study aimed to determine how closely a surgeon's intraoperative ranking of tissue quality during rotator cuff repair correlated to postoperative supraspinatus tendon stiffness measured by SWEUS. Methods: This was a prospective case series on 50 patients undergoing arthroscopic rotator cuff repair, involving SWEUS measurements of each patient's supraspinatus tendon at 8 days, 6 weeks, 12 weeks, 6 months, and 12 months. The intraoperative surgeon score of tissue quality for each patient was ranked on a four-point Likert scale. Each patient's scores were compared to postoperative SWEUS velocity measurements of the supraspinatus tendon postrepair. Results: The SWEUS determined stiffness of supraspinatus tendons at their repaired insertion site postrepair increased by 22% from 6.3 ± 0.2 m/s to 7.7 ± 0.3 m/s over 12 months as the tendons healed (P = .0001). Supraspinatus tendon stiffness was greater in patients with smaller tears (r = -0.50, P = .001) and of younger age (r = -0.58, P = .00001). Surgeons also consistently rated younger patients (rs = -0.49, P = .0001) and smaller tears (rs = -0.56, P = .00001) as having superior intraoperative tendon quality. The correlations between SWEUS velocity and surgeon tissue quality rankings were modest at best and strongest at 12 weeks (rs = 0.27, P = .04). There were modest associations between SWEUS tendon stiffness and surgeon tendon mobility rankings at 6 weeks (rs = 0.26, P = .04) and repair quality rankings at 12 months (rs = 0.36, P = .02). Conclusions: These data support the finding that machines (SWEUS) are better at assessing torn rotator cuff tendon quality and whether that tendon will heal after repair than the 'person' performing the surgery. Supraspinatus tendons lose stiffness as they get older and when the tear is larger, likely explaining why retear post-cuff repair is more common with advanced age and larger tears.

Shoulder Arthroplasty as a Day Case: Is It Better?

Introduction: A retrospective case-controlled study was performed to evaluate the outcomes of shoulder arthroplasty performed as a day case in carefully selected patients, compared to the traditional inpatient approach. Materials and Methods: Patients who had total or hemiarthroplasty of the shoulder performed as a day case or inpatient procedure were recruited. The primary outcome compared rates of uneventful recovery, defined by the absence of complications or readmission to the hospital within six months of surgery, between the inpatient and outpatient groups. Secondary outcomes included examiner-determined functional and patient-determined pain scores at one, six, twelve, and twenty-four weeks post-surgery. A further assessment of patient-determined pain scores was carried out at least two years post-surgery (5.8 ± 3.2). Results: 73 patients (36 inpatients and 37 outpatients) were included in the study. Within this time frame, 25/36 inpatients (69%) had uneventful recoveries compared to 24/37 outpatients (65%) (p = 0.17). Outpatients showed significant improvement over pre-operative baseline levels in more secondary outcomes (strength and passive range-of-motion) by six months post-operation. Outpatients also performed significantly better than inpatients in external rotation (p < 0.05) and internal rotation (p = 0.05) at six weeks post-surgery. Both groups showed significant improvement compared to pre-operative baselines in all patient-determined secondary outcomes except the activity level at work and sports. Inpatients, however, experienced less severe pain at rest at six weeks (p = 0.03), significantly less frequent pain at night (p = 0.03), and extreme pain (p = 0.04) at 24 weeks, and less severe pain at night at 24 weeks (p < 0.01). By a minimum of two years post-operation, inpatients were more comfortable repeating their treatment setting for future arthroplasty (16/18) compared to outpatients (7/22) (p = 0.0002). Conclusions: At a minimum of two years of follow-up, there were no significant differences in rates of complications, hospitalizations, or revision surgeries between patients that underwent shoulder arthroplasty as an inpatient versus an outpatient. Outpatients demonstrated superior functional outcomes but reported more pain at six months post-surgery. Patients in both groups preferred inpatient treatment for any future shoulder arthroplasty. What is Known About This Subject: Shoulder arthroplasty is a complex procedure and has traditionally been performed on an inpatient basis, with patients admitted for six to seven days post-surgery. One of the primary reasons for this is the high level of post-operative pain, usually treated with hospital-based opioid therapy. Two studies demonstrated outpatient TSA to have a similar rate of complications as inpatient TSA; however, these studies only examined patients within a shorter-term 90-day post-operative period and did not evaluate functional outcomes between the two groups or in the longer term. What This Study Adds to Existing Knowledge: This study provides evidence supporting the longer-term results of shoulder arthroplasty done as a day case in carefully selected patients, which are comparable to outcomes in patients that are admitted to the hospital post-surgery.

Acromion and Distal Clavicle Grafts for Arthroscopic Glenoid Reconstruction.

BACKGROUND: We intended to determine if an acromion or distal clavicle bone graft could restore large glenoid defects using two novel, screw-free graft fixation techniques. METHODS: Twenty-four sawbone shoulder models were divided into four groups (n = 6 per group) according to fixation technique and bone graft: (1) modified buckle-down technique with clavicle graft, (2) modified buckle-down technique with acromion graft, (3) cross-link technique with acromion graft, (4) cross-link technique with clavicle graft. Testing was performed sequentially in (1) intact models, (2) after creation of a 30% by-width glenoid defect and (3) after repair. The shoulder joint was translated anteriorly, and glenohumeral contact pressures and load were measured to quantify the biomechanical stability. RESULTS: Maximum contact pressures were restored to 42-56% of intact glenoid using acromion and clavicle grafts with novel fixation techniques. Acromion grafts attained higher maximum contact pressures than clavicle grafts in all groups. Peak translational forces increased by 171-368% after all repairs. CONCLUSIONS: This controlled laboratory study on sawbone models found that both the acromion and distal clavicle are suitable autologous bone graft options for treating large anterior glenoid defects, having appropriate dimensions and contours for reconstructing the glenoid arc. The modified buckle-down and cross-link techniques are two graft fixation techniques that restore stability to the shoulder joint upon repairing a large glenoid defect and are advantageous in being screw-free and simple to execute.

Revision Rotator Cuff Repair With Versus Without an Arthroscopically Inserted Onlay Bioinductive Implant in Workers' Compensation Patients.

Background: The addition of onlay biological grafts to augment difficult rotator cuff repairs has shown encouraging results in a case series. Purpose/Hypothesis: The purpose of this study was to determine whether the addition of an onlay bioinductive implant would improve repair integrity, shear wave elastographic appearance of the repaired tendon and patch, and patient-rated and/or surgeon-measured shoulder function when used in workers' compensation patients undergoing revision arthroscopic rotator cuff repair. We hypothesized that the addition of the bioinductive implant would enhance repair integrity and clinical outcomes compared with standard repair. Study Design: Cohort study; Level of evidence, 3. Methods: A post hoc matched-cohort study was conducted on prospectively recruited workers' compensation patients who received a bioinductive implant for revision rotator cuff repair (n = 19). The control group was selected from consecutive workers' compensation revision rotator cuff repair patients before the introduction of bioinductive implants. Then, they were matched for age and tear size (n = 32). Kaplan-Meier curves were generated to compare the primary outcome of repair integrity between groups. The secondary outcomes were to evaluate the elastographic appearance of the tendon and patch in the bioinductive implant group and to compare patient-rated and surgeon-measured shoulder function between groups preoperatively and at 1 week, 6 weeks, 3 months, and 6 months postoperatively. Results: No major complications associated with the bioinductive implants were identified. Six months after the revision rotator cuff repair, the retear rate in the bioinductive implant group was 16% (3/19), compared with 19% (6/32) in the age- and tear size-matched control group (P = .458). At the final follow-up, the retear rate in the bioinductive implant group was 47% (9/19) at a mean of 14 months compared with 38% (12/32) at a mean of 29 months in the control group (P = .489). The shear wave elastographic stiffness of repaired tendons augmented with the bioinductive implant remained unchanged at 6 m/s from 1 week to 6 months postoperatively, which is lower than the stiffness of 10 m/s in healthy tendons. There were no significant differences in patient-rated or surgeon-measured outcomes between groups 6 months postoperatively. Conclusion: There were no differences in repair integrity or clinical outcomes between workers' compensation patients who underwent revision arthroscopic rotator cuff repair with an onlay bioinductive implant compared to those who underwent standard revision rotator cuff repair.

Ultrasound Guided Arthroscopic Removal of Calcific Tendonitis: A Minimum of 2-Year Followup.

Background: We have developed a novel technique for managing rotator cuff calcific tendonitis, involving arthroscopic debridement of calcific tendonitis with localization assistance from a breast biopsy needle under ultrasound guidance. While we have demonstrated encouraging results at six-month follow-up, the medium-term outcomes and the long-term outcomes of this technique at 2 years or beyond are unknown. The aim of this paper was to determine if this technique was successful in resolving symptoms after two years and beyond. Study Design: Retrospective Cohort Study. Methods: Patients who underwent arthroscopic debridement of calcific tendonitis with localization assistance from a breast biopsy needle under ultrasound guidance by a senior surgeon were evaluated using patient-rated pain scores and functional status with the use of the Likert scales and via examiner-rated shoulder range-of-motion and strength at the pre-operative visit, at 1, 6, 12, and 24 weeks post-operatively, and long-term at a mean of 249 weeks after surgery. Results: At a mean follow-up period of 4.8 years (range, 2-10 years), 31 patients (33 shoulders) experienced significant improvement in the severity of pain at rest, with overhead activities, and during sleep compared to their pre-operative presentation (p < 0.001). The patient experienced less frequent pain during activities and sleep, and a decreased frequency of extreme pain (p < 0.001). Passive range of abduction (p = 0.003), forward flexion (p < 0.001), and supraspinatus strength (p = 0.018) improved compared to the presurgical presentation. Out of 27 patients, 24 patients (89%) had complete resolution of calcific tendonitis, and 26 patients (96%) had an intact rotator cuff. Conclusion: Arthroscopic debridement of calcific tendonitis with localization assistance from a breast biopsy needle under ultrasound guidance was very effective. Patients had significant pain relief, improved range of motion, and a reduction in stiffness at a mean post-operative period of 4.8 years. Patients had a significant reduction in residual calcification, and rotator cuff integrity was largely preserved by long-term follow-up. What is known about this subject: Calcific tendonitis of the rotator cuff is one of the most painful and debilitating disorders of the shoulder. This condition is characterized by the deposition of calcium-phosphate crystals within the rotator cuff tendons. Arthroscopic debridement and excision of rotator cuff calcifications have proven to be efficacious treatments with regards to clinical and functional outcomes in the short and medium term. Identifying the calcific lesion intra-operatively, however, can prove to be challenging. Furthermore, inadequate excision of the calcific deposit has been shown to have poorer clinical outcomes. We designed a technique that utilizes the assistance of ultrasound to guide a localization-biopsy wire to the calcific lesion. This technique aids in precisely identifying the location of the lesion intra-operatively to optimize accuracy in removing the maximum amount of calcific deposit possible. A short-term follow-up study by us has demonstrated successful outcomes with regards to the return of function and relief of pain. However, there have been no studies evaluating the effectiveness of this particular technique beyond six months. What this study adds to current knowledge: At a mean of 4.8 years, arthroscopic debridement of calcific tendonitis, using our technique, was successful in relieving the severity and frequency of pain with overhead activities, pain at rest, and pain during sleep, as well as improving range of motion.

Reliability of a Novel Preoperative Protocol for Determining Graft Sizes for Superior Capsular Reconstruction Using Plain Film Radiography.

BACKGROUND: Superior capsular reconstruction (SCR) for massive, irreparable rotator cuff tears involves anchoring a graft between the superior glenoid and the greater tuberosity of the humerus. Optimizing the graft size is important. We aimed (1) to evaluate the reliability of plain film radiography in determining graft size for SCR and (2) to create a database to help predict future graft sizes. METHODS: An inter- and intra-rater reliability trial was conducted on 10 and 6 subjects with healthy shoulders, respectively, using plain film radiography to measure the distance between the superior glenoid and the supraspinatus footprint. The subjects were positioned upright with an abduction pillow modified to hold the shoulder at 30° abduction and 45° external rotation, afterwhich a true antero-posterior shoulder radiograph was captured. Thirty subjects were recruited for the database and grouped using the aforementioned protocol. RESULTS: The inter-rater and intra-rater trial agreement was excellent, with intraclass correlation coefficients of 0.94 (95% CI) and 0.76 (95% CI), respectively. Three medio-lateral patch sizes, of 33 mm, 38 mm, and 47 mm, were proposed based on the protocol in 30 subjects. CONCLUSIONS: Plain film radiography demonstrated excellent reliability in measuring the distance between the superior glenoid and the supraspinatus footprint. Three ordinal patch sizes are proposed.

Determinants of Operative Time in Arthroscopic Rotator Cuff Repair.

Arthroscopic rotator cuff repairs have been reported to take between 72 and 113 min to complete. This team has adopted its practice to reduce rotator cuff repair times. We aimed to determine (1) what factors reduced operative time, and (2) whether arthroscopic rotator cuff repairs could be performed in under 5 min. Consecutive rotator cuff repairs were filmed with the intent of capturing a <5-min repair. A retrospective analysis of prospectively collected data of 2232 patients who underwent primary arthroscopic rotator cuff repair by a single surgeon was performed using Spearman's correlations and multiple linear regression. Cohen's f2 values were calculated to quantify effect size. Video footage of a 4-min arthroscopic repair was captured on the 4th case. Backwards stepwise multivariate linear regression found that an undersurface repair technique (f2 = 0.08, p < 0.001), fewer surgical anchors (f2 = 0.06, p < 0.001), more recent case number (f2 = 0.01, p < 0.001), smaller tear size (f2 = 0.01, p < 0.001), increased assistant case number (f2 = 0.01, p < 0.001), female sex (f2 = 0.004, p < 0.001), higher repair quality ranking (f2 = 0.006, p < 0.001) and private hospital (f2 = 0.005, p < 0.001) were independently associated with a faster operative time. Use of the undersurface repair technique, reduced anchor number, smaller tear size, increased surgeon and assistant surgeon case number, performing repairs in a private hospital and female sex independently lowered operative time. A <5-min repair was captured.

Biomechanical Comparison of Synthetic Polytetrafluoroethylene (PTFE) vs Human Dermal Allograft (HDA), 2 vs 3 Glenoid Anchors, and Suture vs Minitape in Superior Capsule Reconstruction.

Background: Superior capsule reconstruction (SCR) is an option for the treatment of massive, irreparable rotator cuff tears. However, which materials yield the strongest constructs remains undetermined. Purposes: We sought to investigate whether SCR with polytetrafluoroethylene (PTFE) or human dermal allograft (HDA), 2 or 3 glenoid anchors, and suture or minitape resulted in better failure load properties at the patch-glenoid interface. Methods: We conducted a biomechanical study in 30 glenoid-sided SCR repairs in Sawbones models divided into 5 groups. Each was pulled to failure to assess mode of failure, peak load (N), stiffness (N/mm), yield load (N), peak energy (N m), and ultimate energy (N m). The 5 groups were as follows: group 1-PTFE, 2 anchors, and suture; group 2-PTFE, 2 anchors, and minitape; group 3-HDA, 2 anchors, and suture; group 4-HDA, 2 anchors, and minitape; group 5-PTFE, 3 anchors, and minitape. Results: Repairs failed by button-holing of suture/minitape. Group 5 had greater peak load, stiffness, yield load, and peak energy (384 ± 62 N; 24 ± 3 N/mm; 343 ± 42 N; 4 ± 2 N m) than group 3 (226 ± 67 N; 16 ± 4 N/mm; 194 ± 74 N; 2 ± 1 N m) or group 4 (274 ± 62 N; 17 ± 4 N/mm; 244 ± 50 N; 2 ± 1 N m) and greater ultimate energy (8 ± 3 N m) than all other groups. Conclusions: This biomechanical study of SCR repairs in Sawbones models found that yield load was greater in PTFE than HDA, 3 anchors were better than 2, and minitape was no better than suture.

A Systematic Temporal Assessment of Changes in Tendon Stiffness Following Rotator Cuff Repair.

OBJECTIVES: How the material properties of the human supraspinatus tendon change following arthroscopic rotator cuff repair is undetermined. Shear wave elastography ultrasound is a relatively new, noninvasive measure of tissue stiffness. We aimed to evaluate any temporal changes in stiffness and/or thickness of supraspinatus tendons in humans following primary arthroscopic rotator cuff repair. METHODS: Shear wave elastography was performed at three predetermined regions by a single sonographer at 1-, 6-, 12-, 24-, and 52 weeks postoperatively in 50 consecutive single-row inverted mattress primary arthroscopic rotator cuff repairs. One-way ANOVA with Tukey's correction and Spearman's correlation tests was performed. RESULTS: Of 50 patients, two retore by 1-week and were excluded. Two patients retore at 6 weeks, two at 12 weeks, and one at 24 weeks. The mean tendon stiffness in 48 patients at the tendon footprint increased by 21% (1.32 m/s) at 6 months (P < .001), with the lateral tendon stiffening before the medial tendon. Tendon thickness decreased by 11% (0.6 mm) at 6 weeks (P = .008), then stabilized to 24 weeks. Tendons that were less elastographically stiff at 1 week were more likely to be thinner at 6-weeks (r = .38, P = .010). CONCLUSIONS: The data supports the hypothesis that rotator cuff tendons repaired using the single-row inverted-mattress technique take 6 weeks to heal to bone. Unlike in other tendons, there was no hypertrophic healing response. Prior to 6 weeks, the tendon may stretch/thin-out, particularly if its material properties, as assessed by shear wave elastography, are inferior. The material properties of the tendon improved at the tendon insertion site first, then medially out to 12 months post-repair.

Predictors of Return to Work Following Primary Arthroscopic Rotator Cuff Repair: An Analysis of 1502 Cases.

BACKGROUND: It is undetermined which factors predict return to work after arthroscopic rotator cuff repair. PURPOSE: To identify which factors predicted return to work at any level and return to preinjury levels of work 6 months after arthroscopic rotator cuff repair. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Multiple logistic regression analysis of prospectively collected descriptive, preinjury, preoperative, and intraoperative data from 1502 consecutive primary arthroscopic rotator cuff repairs, performed by a single surgeon, was performed to identify independent predictors of return to work at 6 months postoperatively. RESULTS: Six months after arthroscopic rotator cuff repair, 76% of patients had returned to work, and 40% had returned to preinjury levels of work. Return to work at 6 months was likely if patients were still working after their injuries but before surgery (Wald statistic [W] = 55, P < .0001), were stronger in internal rotation preoperatively (W = 8, P = .004), had full-thickness tears (W = 9, P = .002), and were female (W = 5, P = .030). Patients who continued working postinjury but presurgery were 1.6 times more likely to return to work at any level at 6 months compared to patients who were not working (P < .0001). Patients who had a less strenuous preinjury level of work (W = 173, P < .0001), worked at a mild to moderate level post injury but presurgery, had greater preoperative behind-the-back lift-off strength (W = 8, P = .004), and had less preoperative passive external rotation range of motion (W = 5, P = .034) were more likely to return to preinjury levels of work at 6 months postoperatively. Specifically, patients who worked at a mild to moderate level postinjury but presurgery were 2.5 times more likely to return to work than patients who were not working, or who were working strenuously postinjury but presurgery (p < 0.0001). Patients who nominated their preinjury level of work as "light" were 11 times more likely to return to preinjury levels of work at 6 months compared to those who nominated it as "strenuous" (P < .0001). CONCLUSION: Six months after rotator cuff repair, patients who continued to work after injury but presurgery were the most likely to return to work at any level, and patients who had less strenuous preinjury levels of work were the most likely to return to their preinjury levels of work. Greater preoperative subscapularis strength independently predicted return to work at any level and to preinjury levels.

An evaluation of shear wave elastographic characteristics of the supraspinatus tendon after rotator cuff repair.

BACKGROUND: The main complication of rotator cuff repair is retear, which is most common in older patients and patients with greater tear sizes. However, it is unknown why these factors are associated with increased rates of retear. The aim of this study was to determine whether the factors associated with rotator cuff retear (age, tear size, sex, history of trauma, and duration of symptoms) are also associated with decreased mechanical stiffness of the supraspinatus tendon after repair, as assessed by shear wave elastography. METHODS: This was a prospective study of 50 patients undergoing primary rotator cuff repair. A sonographer conducted shear wave elastography ultrasound in all patients at 1, 6, 12, 26, and 52 weeks after repair. The shear wave velocity of the supraspinatus tendon was measured at the tendon-bone interface, 3 mm medial to the interface, and 6 mm medial to the interface. A multiple linear regression analysis was performed with calculation of Cohen F2 values to determine the factors that independently affected supraspinatus tendon stiffness postoperatively. RESULTS: For every decade increase in age, the shear wave velocity of the supraspinatus tendon decreased by 0.5 m/s (P = .004). Greater tear size correlated with reduced supraspinatus shear wave velocity (P < .03 at 6 weeks). Male patients had greater supraspinatus tendon stiffness than female patients (8.2 m/s vs. 6.9 m/s, P = .04). Tendons in patients with a history of trauma were approximately 16% stiffer postoperatively than those in patients with no trauma history (P < .001). Duration of symptoms had no impact on the mechanical stiffness of the supraspinatus tendon. CONCLUSION: Older age, larger tear size, female sex, and nontraumatic tear causation were independently associated with reduced shear wave velocity of the supraspinatus tendon postoperatively. The findings of our study correlate with the results of cohort studies assessing the influence of these variables on rotator cuff retear rates, suggesting that the mechanical stiffness of the supraspinatus tendon, as assessed by shear wave elastography, may have an important association with a successful repair.

Superior and Anterior Glenoid Labral Tears Are Associated With Increased Neurofilament Concentration.

BACKGROUND: Pain is a common presentation after glenohumeral labral injuries. However, the source of that pain is undetermined. PURPOSE/HYPOTHESIS: We aimed to determine if there is a differential expression of nerve fibers around the glenoid labrum and if torn labra have increased neuronal expression compared with untorn labra (rotator cuff repair labra). We hypothesized that the superior labrum would have a higher concentration of neurofilament than would the rest of the labrum and that the concentration of neurofilament would increase at the site of a labral tear. STUDY DESIGN: Descriptive laboratory study. METHODS: Seven labra were sampled at the 3-, 5-, 9-, and 12-o'clock positions during total shoulder arthroplasty. Samples were also collected at the 3-, 5-, and 12-o'clock positions during rotator cuff repair (16 labra), anterior labral repair (6 labra), type II superior labral anterior to posterior (SLAP) repair (4 labra), and capsular release for idiopathic capsulitis (5 labra). Sections were immunostained with antibodies to neurofilament, a specific neuronal marker that is used to identify central and peripheral nerve fibers, and the concentration and intensity of immunostained-positive cells assessed. RESULTS: The concentration of neurofilament staining was similar in the superior, anterior, posterior, and inferior glenoid labrum in untorn labra (8 neurofilament expressing cells per square millimeter; P = .3). Torn labra exhibited a 3- to 4-fold increase in neuronal expression, which was isolated to the location of the tear in SLAP (P = .09) and anterior labral tears (P = .02). The concentration of neurofilament expressing cells in torn glenoid labrum samples was comparable that in with the glenoid labrum of adhesive capsulitis samples (P = .7). CONCLUSION: This study supports the hypothesis that after a tear of the anterior or superior labrum the labrum in that region becomes populated with new nerves fibers and that these fibers may be responsible for the pain noted by patients with superior (SLAP) and/or anterior labral (Bankart) tears. CLINICAL RELEVANCE: This study suggests that neural infiltration contributes to the pain experienced by patients with labral tears. It may help with patient education and direct future management of labral lesions.

Biomechanical and morphological comparison of two interposition graft rotator cuff repair techniques.

BACKGROUND: Interposition graft rotator cuff repair is one option for the treatment of massive, otherwise irreparable rotator cuff tears. It is undetermined how different suturing techniques influence morphology at the patch-tendon interface in interposition rotator cuff repairs, particularly with respect to increased cross-sectional area at the repair site post-exposure to cyclic loading, which may influence healing. We aimed to analyze how the morphology of the grafts used in polytetrafluoroethylene (PTFE) interposition rotator cuff repairs differed according to whether the graft was secured using the multiple mattress technique or the weave technique respectively. METHODS: Twelve PTFE interposition rotator cuff repairs (two groups, n = 6) were cyclically loaded. The thickness, width, cross-sectional area at the individual patches and at the repair site, and patch elongation were compared between repairs using the 'multiple mattress' technique and repairs that used the 'weave' technique. RESULTS: At all loads, repair site cross-sectional area and thickness was greater in the weave group than in the multiple mattress group (P<0.05), despite repair site width being greater in the multiple mattress group (P<0.05). No significant differences in elongation were found between the multiple mattress and weave groups. CONCLUSION: Greater repair site cross-sectional area under cyclic loading was observed in polytetrafluoroethylene interposition rotator repairs that used the weave technique than in those that used the multiple mattress technique. Increased repair site cross-sectional area in the weave group occurred due to increased thickness and decreased width relative to the multiple mattress group. No differences in cross-sectional area were found between groups at the individual patches.

Factors influencing clinical outcomes in superior capsular reconstruction: A scoping review.

Background: It is undetermined how effective superior capsule/capsular reconstruction (SCR) is, and which factors influence clinical outcomes. Questions/purposes: (1) To identify which factors influence outcomes in SCR, (2) to evaluate the effect of graft integrity on clinical outcomes, and (3) to compare SCR to other procedures for irreparable rotator cuff tears. Methods: PubMed and EMBASE databases were searched for clinical SCR studies. Data on specific factors that influenced outcomes, that compared outcomes between intact/torn graft groups, or compared SCR to alternative treatments for irreparable tears were extracted by two investigators. Random-effects meta-analysis was performed to compare outcomes between intact vs torn SCR grafts. Results: 394 articles were identified. 100 full-text articles were screened. 13 studies were included for scoping review. Eight studies were meta-analyzed. Better clinical scores were found in younger patients, with intact/repairable subscapularis, without acetabulization/arthritis, who played sports. In patients with irreparable tears without arthritis, SCR produced similar clinical scores at 2 years as shoulder arthroplasty and partial infraspinatus repair, and greater improvements in ASES and Constant scores than latissimus dorsi tendon transfer. Intact grafts produced better VAS (mean difference [MD] = 0.97, 95% confidence interval [-1.45-0.50], P < 0.0001, I 2 = 67%, n [patients] = 261), ASES (MD = 8.29, [2.89-13.70], P = 0.003, I 2 = 74%, n = 281), external rotation (MD = 4.49, [0.36-8.61], P = 0.03, I 2 = 0%, n = 240), and acromiohumeral distance (MD = 2.45, [0.96-3.94], P = 0.001, I 2 = 92%, n = 260) than torn grafts. Conclusions: Patients who underwent SCR for irreparable rotator cuff tears were more likely to have better clinical outcomes if they were younger, had intact/repairable subscapularis, without acetabulization/arthritis, played sports and had intact grafts.