Biologic Adjuvants to Rotator Cuff Repairs Induce Anti-inflammatory Macrophage 2 Polarization and Reduce Inflammatory Macrophage 1 Polarization In Vitro.

PURPOSE: To examine the effect of various biologic adjuvants on the polarization of macrophages in an in vitro model for rotator cuff tears. METHODS: Tissue was harvested from 6 patients undergoing arthroscopic rotator cuff repair. An in vitro model of the supraspinatus and subacromial bursa was created and treated with control, platelet-rich plasma (PRP), autologous activated serum (AAS), or a combination of PRP+AAS. The effect of treatment on macrophage polarization between M1 proinflammatory macrophages or M2 anti-inflammatory macrophages was measured using gene expression, protein expression, flow cytometry, and nitric oxide production. RESULTS: Tendon and bursa treated with PRP, AAS, and PRP+AAS significantly decreased the gene expression of M1 markers interleukin (IL)-12 and tumor necrosis factor-alpha while significantly increasing the expression of M2 markers arginase, IL-10, and transforming growth factor-ß (P < .05) compared with treatment with control. Enzyme-linked immunosorbent assay analysis of protein production demonstrated that, compared with control, coculture treated with PRP, AAS, and PRP+AAS significantly decreased markers of M1-macrophages (IL-6, IL-12, and tumor necrosis factor-alpha) while significantly increasing the expression of markers of M2-macrophages (arginase, IL-10, and transforming growth factor-beta) (P < .05). Flow cytometry analysis of surface markers demonstrated that compared with control, tendon and bursa treated with PRP, AAS, and PRP+AAS significantly decreased markers of M1-macrophages (CD80, CD86, CD64, CD16) while significantly increasing the expression of markers of M2-macrophages (CD163 and CD206) (P < .05). Treatment of the coculture with PRP, AAS, and PRP+AAS consistently demonstrated a decrease in nitric oxide production (P < .05) compared with control. AAS and PRP+AAS demonstrated an increased macrophage shift to M2 compared with PRP alone, whereas there was not as uniform of a shift when comparing PRP+AAS with AAS alone. CONCLUSIONS: In an in vitro model of rotator cuff tears, the treatment of supraspinatus tendon and subacromial bursa with PRP, AAS, and PRP+AAS demonstrated an increase in markers of anti-inflammatory M2-macrophages and a concomitant decrease in markers of proinflammatory M1-macrophages. AAS and PRP+AAS contributed to a large shift to macrophage polarization to the anti-inflammatory M2 compared with PRP. CLINICAL RELEVANCE: The mechanism of biologic adjuvant effects on the rotator cuff remains poorly understood. This study suggests that they may contribute to polarization of macrophages for their proinflammatory (M1) state to the anti-inflammatory (M2) state.

Human Rotator Cuff Tears Reveal an Age-Dependent Increase in Markers of Cellular Senescence and Selective Removal of Senescent Cells With Dasatinib + Quercetin Increases Genetic Expression of COL1A1 In Vitro.

PURPOSE: To quantify cellular senescence in supraspinatus tendon and subacromial bursa of humans with rotator cuff tears and to investigate the in vitro efficacy of the senolytic dasatinib + quercetin (D+Q) to eliminate senescent cells and alter tenogenic differentiation. METHODS: Tissue was harvested from 41 patients (mean age, 62 years) undergoing arthroscopic rotator cuff repairs. In part 1 (n = 35), senescence was quantified using immunohistochemistry and gene expression for senescent cell markers (p16 and p21) and the senescence-associated secretory phenotype (SASP) (interleukin [IL] 6, IL-8, matrix metalloproteinase [MMP] 3, monocyte chemoattractant protein [MCP] 1). Senescence was compared between patients <60 and ≥60 years old. In part 2 (n = 6) , an in vitro model of rotator cuff tears was treated with D+Q or control. D+Q, a chemotherapeutic and plant flavanol, respectively, kill senescent cells. Gene expression analysis assessed the ability of D+Q to kill senescent cells and alter markers of tenogenic differentiation. RESULTS: Part 1 revealed an age-dependent significant increase in the relative expression of p21, IL-6, and IL-8 in tendon and p21, p16, IL-6, IL-8, and MMP-3 in bursa (P < .05). A significant increase was seen in immunohistochemical staining of bursa p21 (P = .028). In part 2, D+Q significantly decreased expression of p21, IL-6, and IL-8 in tendon and p21 and IL-8 in bursa (P < .05). Enzyme-linked immunosorbent assay analysis showed decreased release of the SASP (IL-6, MMP-3, MCP-1; P = .002, P = .024, P < .001, respectively). Tendon (P = .022) and bursa (P = .027) treated with D+Q increased the expression of COL1A1. CONCLUSIONS: While there was an age-dependent increase in markers of cellular senescence, this relationship was not consistently seen across all markers and tissues. Dasatinib + quercetin had moderate efficacy in decreasing senescence in these tissues and increasing COL1A1 expression. CLINICAL RELEVANCE: This study reveals that cellular senescence may be a therapeutic target to alter the biological aging of rotator cuffs and identifies D+Q as a potential therapy.

Biomechanical evaluation of subscapularis peel repairs augmented with the long head of the biceps tendon for anatomic total shoulder arthroplasty.

BACKGROUND: Subscapularis failure is a troublesome complication following anatomic total shoulder arthroplasty (aTSA). Commonly discarded during aTSA, the long head of the biceps tendon (LHBT) may offer an efficient and cheap autograft for the augmentation of the subscapularis repair during aTSA. The purpose of this study was to biomechanically compare a standard subscapularis peel repair to 2 methods of subscapularis peel repair augmented with LHBT. METHODS: 18 human cadaveric shoulders (61 ± 9 years of age) were used in this study. Shoulders were randomly assigned to biomechanically compare subscapularis peel repair with (1) traditional single-row repair, (2) single row with horizontal LHBT augmentation, or (3) single row with V-shaped LHBT augmentation. Shoulders underwent biomechanical testing on a servohydraulic testing system to compare cyclic displacement, load to failure, and stiffness. RESULTS: There were no significant differences in the cyclic displacement between the 3 techniques in the superior, middle, or inferior portion of the subscapularis repair (P > .05). The horizontal (436.7 ± 113.3 N; P = .011) and V-shape (563.3 ± 101.0 N; P < .001) repair demonstrated significantly greater load to failure compared with traditional repair (344.4 ± 82.4 N). The V-shape repair had significantly greater load to failure compared to the horizontal repair (P < .001). The horizontal (61.6 ± 8.4 N/mm; P < .001) and the V-shape (62.8 ± 6.1; P < .001) repairs demonstrated significantly greater stiffness compared to the traditional repair (47.6 ± 6.2 N). There was no significant difference in the stiffness of the horizontal and V-shape repairs (P = .770). CONCLUSIONS: Subscapularis peel repair augmentation with LHBT autograft following aTSA confers greater time zero load to failure and stiffness when compared to a standard subscapularis peel repair.

Suture Tape Augmentation for the Repair of Index Finger Radial Collateral Ligament Injury: A Biomechanical Study.

PURPOSE: Despite their clinical importance in maintaining the stability of the pinch mechanism, injuries of the radial collateral ligament (RCL) of the index finger may be underrecognized and underreported. The purpose of this biomechanical study was to compare the repair of index finger RCL tears with either a standard suture anchor or suture tape augmentation. METHODS: The index fingers from 24 fresh-frozen human cadavers underwent repair of torn RCLs using either a standard suture anchor or suture tape augmentation. Following the repairs, the initial displacement of the repair with a 3-N ulnar deviating load was evaluated. Next, the change in displacement (cyclic deformation) of the repair after 1,000 cycles of 3 N of ulnar deviating force was calculated (displacement of the 1000th cycle - displacement of the first cycle). Finally, the amount of force required to cause clinical failure (30° ulnar deviation) of the repair was determined. RESULTS: Suture tape augmentation repairs displayed significantly less cyclic deformation (0.8 ± 0.5 mm) after cyclic loading than suture anchor repairs (1.8 ± 0.7 mm). There was no significant difference in the force required to cause the clinical failure of the repairs between the suture tape (35.1 ± 18.1 N) and suture anchor (24.5 ± 9.2 N) repairs. CONCLUSIONS: Index finger RCL repair with suture tape augmentation results in decreased deformation with repetitive motion compared with RCL repair alone. CLINICAL RELEVANCE: Suture tape augmentation may allow for early mobilization following index finger RCL repair by acting as a brace that protects the repaired ligament from deforming forces.

Bicortical suspensory button fixation yields greater ultimate load to failure over unicortical all-suture anchor fixation in distal biceps brachii tendon repair.

BACKGROUND: Various distal biceps tendon repair techniques exist, each with their own biomechanical profile. Recently, all-suture anchor fixation has recently become an intriguing option for distal biceps fixation, compared with the proven track record of the suspensory cortical button. In addition, intramedullary techniques have been utilized as a means to avoid complications such as nerve damage seen with extramedullary fixation. PURPOSE: The purpose of this study is to perform a comparative biomechanical analysis of 4 unique distal biceps tendon fixation methods: Unicortical/intramedullary all-suture anchor fixation (UIAS), Bicortical/extramedullary all-suture anchor fixation (BEAS), Unicortical/intramedullary suspensory button fixation (UISB), and Bicortical/extramedullary suspensory button fixation (BESB). STUDY DESIGN: Controlled Laboratory study. METHODS: 24 fresh-frozen cadaveric elbows were randomized into 4 groups providing data from 6 specimens, with each group undergoing a different repair technique. The specimens underwent 2 studies: Cyclic loading and Ultimate Load to failure (ULTF) testing. The repaired elbows were cycled 3000 times between 0 and 90 degrees of flexion, with displacement under cyclic loading at the repair site measured using a differential variable reductance transducer. ULTF test was performed with the elbow flexed at 90 degrees. The modes of failure were recorded. RESULTS: The mean cyclic displacements between the 4 groups were as follows: UIAS: 1.45 ± 1.04 mm; BEAS: 2.75 ± 1.32 mm; UISB: 1.45 ± .776 mm; BESB: 2.66 ± 1.18 mm (p= 0.077). Bicortical repairs displayed greater displacement after cyclic loading when compared with unicortical repairs regardless of anchor used (p= 0.007). The mean ULTF for each group was as follows: all-suture intramedullary: 200 N; all-suture extramedullary: 330 N; cortical-button intramedullary: 256 N; cortical-button extramedullary: 342 N). All-suture unicortical/intramedullary repair had a significantly lower ULTF (200 N) compared with cortical-button Bicortical/extramedullary repair (342 N) (p=0.043). CONCLUSION: Bicortical/extramedullary suspensory button fixation demonstrated a greater ultimate load to failure when compared with unicortical/intramedullary all-suture anchor fixation. These findings suggest that bicortical/extramedullary suspensory cortical button fixation is a biomechanically superior construct as compared to unicortical/intramedullary all-suture anchor fixation. However, there was no significant difference in ULTF between extra-medullary, Bicortical button or Bicortical, all-suture anchor fixation.

Reverse Shoulder Arthroplasty Patients Younger Than 60 Years Old Exhibit Lower Clinically Significant Single Assessment Numeric Evaluation (SANE) Scores Compared to Older Patients.

INTRODUCTION: The incidence of reverse shoulder arthroplasty (RTSA) in the United States has increased. Patients under 60 years old with failed rotator cuff repairs or degenerative joint disease with glenoid deformity may be candidates for RTSA and contribute to this increase. The single assessment numeric evaluation (SANE) score is a reliable post-operative scoring technique when compared with other post-operative measures. This study aimed to compare the effect of age on the likelihood of reaching clinically significant SANE scores following RTSA. METHODS: A multicenter retrospective review was performed with a consecutive series of RTSA from December 2015 to September 2021. Patients were stratified into groups based on their age at the time of operation: (1) less than 60 years old, (2) 60-69 years old, (3) 70-79 years old, and (3) greater than 80 years old. The proportions of patients in all cohorts reaching and surpassing clinically significant thresholds at each visit were determined. Likelihood ratios were determined for each age cohort to compare the likelihood of reaching clinically significant SANE scores. RESULTS: A total of 292 of 885 (33%) patients had completed survey data over two years and were included in the study. The 70-79-year-old group was 3.152 (p=.035) times more likely to achieve minimal clinically important difference (MCID) and 2.125 (p=.048) times more likely to achieve patient-acceptable symptomatic state (PASS) compared with patients <60 years old. The cohort who was 80+ years old was also 4.867 (p=.045) times more likely to achieve MCID compared to the <60-year-old cohort. The <60 cohort had the lowest proportion of all patient cohorts achieving MCID. CONCLUSION: A lower proportion of patients younger than 60 years old undergoing RTSA achieved clinically significant post-operative SANE scores. The 70-79-year-old age group was more likely to reach MCID and PASS, and the patients who were 80+ years old were more likely to reach MCID compared to patients younger than 60 years old.

Plate vs. intramedullary screw fixation of chevron olecranon osteotomies: a biomechanical study.

Background: Intra-articular distal humerus fractures frequently require olecranon osteotomies for adequate exposure, but fixation of olecranon osteotomies is associated with high rates of hardware-related complications requiring subsequent reoperation for removal. Intramedullary screw fixation is an attractive option to attempt to minimize hardware prominence. The purpose of this biomechanical study is to directly compare intramedullary screw fixation (IMSF) with plate fixation (PF) of chevron olecranon osteotomies. It was hypothesized that PF would be biomechanically superior to IMSF. Methods: Chevron olecranon osteotomies of 12 matched pairs of fresh-frozen human cadaveric elbows were repaired with either precontoured proximal ulna locking plates or cannulated screws with a washer. Displacement and amplitude of displacement at the dorsal and medial aspects of the osteotomies under cyclic loading conditions were measured. Finally, the specimens were loaded to failure. Results: The IMSF group had significantly greater medial displacement (P = .034) and dorsal amplitude (P = .029) than the PF group. Medial displacement was negatively correlated with bone mineral density in the IMSF group (r = -0.66, P = .035) but not in the PF group (r = .160, P = .64). Mean load to failure between groups, however, was not statistically significant (P = .183). Conclusions: While there was no statistically significant difference in the load to failure between the two groups, IMSF repair resulted in significantly greater displacement of the medial osteotomy site during cyclic loading and greater amplitude of displacement dorsally with loading force. Decreased bone mineral density was associated with an increased displacement of the medial repair site. These results suggest that IMSF of olecranon osteotomies may result in increased fracture site displacement when compared to PF; this displacement may be greater in patients with poor bone quality.

Location of distal pronator quadratus repair in distal radius fractures: A cadaveric biomechanical study.

BACKGROUND: We aimed to biomechanically evaluate the distal pronator quadratus and compare two locations of distal transection on the strength of the subsequent repair. METHODS: Eighteen fresh-frozen cadaveric specimens were dissected to the pronator quadratus muscle. Specimens were randomly allocated for transection of the pronator quadratus at the myotendinous junction (red group) or parallel to the myotendinous junction at the midsection of the distal tendinous zone (white group). For both groups, repair of the muscle was performed using two figure-of-8 sutures. The radius and ulna were positioned in 90° of wrist extension. The proximal muscular pronator quadratus was fixed in a cryo-clamp. Load-to-failure testing of the repair was performed at 1 mm/s with maximum amount of force applied to the pronator quadratus recorded for each specimen. FINDINGS: The pronator quadratus had a mean width, height, and area of 31.41 ± 5.74 mm, 53.79 ± 7.46 mm, and 1604.27 ± 429.20 mm2 respectively. The pronator quadratus distal tendinous zone had a mean width, height, and area of 29.71 ± 5.83 mm, 12.22 ± 2.79 mm, 282.94 ± 148.30 mm2 respectively. There was no significant difference between the two groups for pronator quadratus height, width, total area, or tendinous zone height, width, or total area. The average load to failure for the white group was significantly higher than that of the red group (29.46 ± 4.24 N vs. 13.78 N ± 6.66 N). INTERPRETATION: Incision and repair of the pronator quadratus in the distal tendinous region is stronger than incision and repair at the red myotendinous junction of the distal PQ.

Biomechanical Efficacy of Tape Cerclage as an Augment or Stand-alone for Coracoclavicular Ligament Reconstruction.

BACKGROUND: Loss of initial reduction of the acromioclavicular joint after coracoclavicular (CC) ligament reconstruction remains a challenge for various repair techniques. Previous studies using polydioxanone suture cerclage augments for CC ligament reconstruction demonstrated poor clinical and biomechanical outcomes. Tape-style sutures have recently gained popularity because of their added stiffness and strength relative to traditional sutures. These tape cerclage systems have yet to be biomechanically studied in CC ligament reconstruction. PURPOSE: To determine the efficacy of a tape cerclage system as an augment to CC ligament reconstruction. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 24 human cadaveric shoulders were utilized. These were divided into 4 repair groups: anatomic CC ligament reconstruction (ACCR), ACCR with a tape cerclage augment (ACCR + C), tendon graft sling with a cerclage augment (TGS + C), or tape cerclage sling alone (CS). The repairs underwent superior/inferior cyclic loading to evaluate for displacement. Specimens were visually inspected for cortical erosion by the tape cerclage after cyclic loading. Finally, the constructs underwent superior plane load-to-failure testing. RESULTS: Less displacement after cyclic loading was observed in the ACCR + C (mean ± SD, 0.42 ± 0.32 mm), TGS + C (0.92 ± 0.42 mm), and CS (0.93 ± 0.39 mm) groups as compared with the ACCR group (4.42 ± 3.40 mm; P = .002). ACCR + C (813.3 ± 257.5 N), TGS + C (558.0 ± 120.7 N), and CS (759.5 ± 173.7 N) demonstrated significantly greater load at failure relative to ACCR (329.2 ± 118.2 N) (P < .001). ACCR + C (60.88 ± 17.3 N/mm), TGS + C (44.97 ± 9.15 N/mm), and CS (54.52 ± 14.24 N/mm) conferred greater stiffness than ACCR (27.43 ± 6.94 N/mm) (P = .001). No cortical erosion was demonstrated in any specimen after cyclic loading. CONCLUSION: In a cadaveric model at time zero, repairs utilizing a tape cerclage system confer significantly greater load to failure and stiffness, as well as decreased displacement with cyclic loading, when compared with traditional ACCR repair. CLINICAL RELEVANCE: Tape cerclage augmentation may provide a useful augment for CC ligament reconstruction.

Deltotrapezial Stabilization of Acromioclavicular Joint Rotational Stability: A Biomechanical Evaluation.

Background: Despite advances in surgical management of acromioclavicular (AC) joint reconstruction, many patients fail to maintain sustained anatomic reduction postoperatively. Purpose: To determine the biomechanical support of the deltoid and trapezius on AC joint stability, focusing on the rotational stability provided by the muscles to posterior and anterior clavicular rotation. A novel technique was attempted to repair the deltoid and trapezius anatomically. Study Design: Controlled laboratory study. Methods: Twelve human cadaveric shoulders (mean ± SD age, 60.25 ± 10.25 years) underwent servohydraulic testing. Shoulders were randomly assigned to undergo serial defects to either the deltoid or trapezius surrounding the AC joint capsule, followed by a combined deltotrapezial muscle defect. Deltotrapezial defects were repaired with an all-suture anchor using an anatomic technique. The torque (N·m) required to rotate the clavicle 20° anterior and 20° posterior was recorded for the following conditions: intact (native), deltoid defect, trapezius defect, combined deltotrapezial defect, and repair. Results: When compared with the native condition, the deltoid defect decreased the torque required to rotate the clavicle 20° posteriorly by 7.1% (P = .206) and 20° anteriorly by 6.1% (P = .002); the trapezial defect decreased the amount of rotational torque posteriorly by 5.3% (P = .079) and anteriorly by 4.9% (P = .032); and the combined deltotrapezial defect decreased the amount of rotational torque posteriorly by 9.9% (P = .002) and anteriorly by 9.4% (P < .001). Anatomic deltotrapezial repair increased posterior rotational torque by 5.3% posteriorly as compared with the combined deltotrapezial defect (P = .001) but failed to increase anterior rotational torque (P > .999). The rotational torque of the repair was significantly lower than the native joint in the posterior (P = .017) and anterior (P < .001) directions. Conclusion: This study demonstrated that the deltoid and trapezius play a role in clavicular rotational stabilization. The proposed anatomic repair improved posterior rotational stability but did not improve anterior rotational stability as compared with the combined deltotrapezial defect; however, neither was restored to native stability. Clinical Relevance: Traumatic or iatrogenic damage to the deltotrapezial fascia and the inability to restore anatomic deltotrapezial attachments to the acromioclavicular joint may contribute to rotational instability. Limiting damage and improving the repair of these muscles should be a consideration during AC reconstruction.

Biomechanical Evaluation of the Efficacy of Suture Tape Augmentation for Subscapularis Peel Repair.

Background: Failure of a subscapularis repair construct after anatomic total shoulder arthroplasty can result in difficulty with internal rotation and an increased likelihood of dislocation. Although suture tape has been demonstrated to be an efficacious augment for tendonous repairs elsewhere in the body, it has not been investigated as a method for augmenting subscapularis peel repairs. Purpose: To determine the biomechanical efficacy of suture tape augmentation for the repair of a subscapularis peel. Study Design: Controlled laboratory study. Methods: Twelve human cadaveric shoulders underwent a subscapularis peel. Specimens were randomly split into 2 groups: 6 specimens underwent repair using a transosseous bone tunnel technique with 3 high-strength sutures placed with a Mason-Allen configuration (control group), and 6 specimens underwent the control repair using augmentation with 2 suture tapes placed in an inverted mattress fashion and secured to the proximal humerus using a suture anchor (augmentation group). Shoulders underwent biomechanical testing to compare repair displacement with cyclic loading, load at ultimate failure, and construct stiffness. Results: There were no significant between-group differences in displacement after cyclic loading at the superior (P = .87), middle (P = .47), or inferior (P = .77) portions of the subscapularis tendon. Load to failure was significantly greater in the augmentation group (585.1 ± 97.4 N) than in the control group (358.5 ± 81.8 N) (P = .001). Stiffness was also greater in the augmentation group (71.8 ± 13.7 N/mm) when compared with the control group (48.7 ± 5.7 N/mm) (P = .003). Conclusion: Subscapularis peel repair with augmentation via 2 inverted mattress suture tapes secured with an anchor in the proximal humerus conferred significantly greater load at ultimate failure and construct stiffness when compared with a traditional repair using 3 Mason-Allen sutures. There was no difference in repair displacement with cyclic loading between the repair groups. Clinical Relevance: Suture tape augmentation of subscapularis peel repairs after shoulder arthroplasty provides an effective segment to the strength of the repair.

Substantial clinical benefit values demonstrate a high degree of variability when stratified by time and geographic region.

Background: A Substantial Clinical Benefit (SCB) value is the amount of change in a patient-reported outcome measure required for a patient to feel they significantly improved from an intervention. Previously published SCB values are often cited by researchers when publishing outcomes data. Where these SCB values are set can have a large impact on the conclusions drawn from a study citing them. As such, the goal of this study was to determine the generalizability of SCB values for a procedure when stratified by time from surgery and geographic region. Methods: A nationwide outcomes database was utilized to obtain preoperative, one-year, and two-year postoperative outcome measurements for patients who underwent anatomic total shoulder arthroplasty (TSA) or reverse TSA. The data were divided into three geographic regions: the South, the Midwest, and the West. An East region was not included due to its limited number of patients. SCB values were calculated for four outcomes measures: Single Assessment Numeric Evaluation score, American Shoulder Elbow Surgeons score, Visual Analog Scale, and Western Ontario Osteoarthritis of the Shoulder score. SCB values were calculated for each region, for each procedure, and at both one and two years postoperatively. To determine the variability of potential SCBs within each region, simulated datasets were created to determine a distribution of possible calculated SCBs. Results: A total of 380 anatomic TSA patients and 543 reverse TSA patients were included for analysis. There was a high degree of variability of SCB values when stratified by procedure, time, and region. While some simulated datasets did produce homogenous SCB distributions among regions, some outcome measures demonstrated a large heterogeneity in distribution among regions, with concomitant large distributions of values within individual regions. Conclusions: There is notable heterogeneity of SCB values when stratified by region or time. The current method of citing previously published SCB values for determining the efficacy of an intervention may be inappropriate. It is likely that this variability holds true in other areas of orthopedics.

Optimization of tissue adhesive curing time for surgical wound closure.

AIMS: Tissue adhesives (TAs) are a commonly used adjunct to traditional surgical wound closures. However, TAs must be allowed to dry before application of a surgical dressing, increasing operating time and reducing intraoperative efficiency. The goal of this study is to identify a practical method for decreasing the curing time for TAs. METHODS: Six techniques were tested to determine which one resulted in the quickest drying time for 2-octyle cyanoacrylate (Dermabond) skin adhesive. These were nothing (control), fanning with a hand (Fanning), covering with a hand (Covering), bringing operating room lights close (OR Lights), ultraviolet lights (UV Light), or prewarming the TA applicator in a hot water bath (Hot Water Bath). Equal amounts of TA were applied to a reproducible plexiglass surface and allowed to dry while undergoing one of the six techniques. The time to complete dryness was recorded for ten specimens for each of the six techniques. RESULTS: Use of the Covering, OR Lights, and Hot Water Bath techniques were associated with a 25- (p = 0.042), 27- (p = 0.023), and 30-second (p = 0.009) reduction in drying time, respectively, when compared to controls. The UV Light (p = 0.404) and Fanning (p = 1.000) methods had no effect on drying time. CONCLUSION: Use of the Covering, OR Lights, and Hot Water Bath techniques present a means for reducing overall operating time for surgeons using TA for closure augmentation, which can increase intraoperative efficiency. Further studies are needed to validate this in vivo.Cite this article: Bone Jt Open 2022;3(8):607-610.

Glenohumeral Arthrodesis for Treatment of Unique Instability with Axillary Nerve Injury: A Case Report.

Introduction: Traumatic shoulder dislocations in elderly patients can result in significant shoulder pathology. Rotator cuff tears and recurrent instability are common complications follow a dislocation event, while axillary nerve injury is less common. While there have been rare cases of recurrent shoulder instability with concomitant axillary nerve injury, there have been no prior cases, in which concurrent fracture fragmentation resulted in the initial gross instability. Case Report: A 68-year-old male with painful gross instability presents following a traumatic dislocation. The patient sustained an axillary nerve injury to the ipsilateral side resulting in a non-functioning deltoid. Pre-operative X-rays showed recurrent chronic glenohumeral dislocation, computerized tomography imaging showed a greater tuberosity fracture, and magnetic resonance imaging showed a massive cuff tear with retraction and atrophy. Given the level of instability and deltoid dysfunction, the patient was treated with shoulder arthrodesis. Intraoperatively, a large fragment of greater tuberosity with ligamentous attachments was found adhered to the anterior glenoid. After arthrodesis, the patient's pain and function improved significantly. Conclusion: When treating elderly patients with gross instability following a traumatic dislocation, surgeons should keep in mind the high likelihood of concomitant avulsion fracture, and that migratory cortical fragments can be a nidus for a patient's instability. When selected for appropriately, these patients can be effectively treated with shoulder arthrodesis with excellent improvements of pain and functionality.

Activated Serum Increases In Vitro Cellular Proliferation and Growth Factor Expression of Musculoskeletal Cells.

The purpose of this study was to investigate proteomic alteration that occurs to whole blood when converted to activated serum (AS) using an autologous thrombin system. This study further sought to evaluate the functional in vitro effect of AS on tenocytes, chondrocytes, subacromial bursal cells, and osteoblasts. The peptide/protein composition of AS was analyzed by liquid chromatography−mass spectrophotometry (LC-MS). The cell lines were treated with AS, and cellular proliferation was quantified 48 h after treatment. Platelet-derived growth factor (PDGF), insulin-like growth factor 1 (IGF-1), vascular endothelial growth factor (VEGF), interleukin-1 beta (IL-1ß), and interleukin-1 receptor antagonist (IL-1Ra) were quantified utilizing enzyme-linked immunosorbent assays (ELISAs). LC-MS identified 357 proteins across the AS and whole blood. Fifty-four of the proteins identified had significant differences between the relative protein abundance of the AS samples compared to whole blood. Treatment with AS in all cell lines significantly increased proliferation compared to control cells at 48 h. Increased PDGF, VEGF, and IGF-1 in all cell lines exposed to AS compared to the control (p < 0.05) were observed. These findings suggest that treatment with AS increases in vitro cellular proliferation and the release of growth factors that may play a role in tissue repair.

Efficacy of Arthroscopic Shavers for the Retrieval and Processing of Connective Tissue Progenitor Cells from Subacromial Bursal Tissue.

The purpose of this study is to determine if arthroscopic shavers can effectively collect and process connective tissue progenitor (CTP) cells from subacromial bursal tissue for utilization in rotator cuff repair augmentation. Subacromial bursal tissue was collected and processed using two arthroscopic shavers, Shaver A and Shaver B, in 10 patients undergoing arthroscopic rotator cuff repair. Each shaver was used in a random order for the same patient. Tissue samples underwent testing for cellular proliferation, cellular concentration, number of colony-forming units (CFU), live/dead assay, fluorescence-activated cells sorting (FACS) analysis, cytokine analysis, and growth factor analysis. Shaver A produced more CFUs compared to Shaver B (210.3 vs. 125.9; p < 0.001). At 3 weeks, cells collected via Shaver A had greater cellular proliferation (0.35 vs. 0.51; p < 0.001) as well as more viable cells (214,773 vs. 132,356 cells/gram; p < 0.001). Tissue collected with Shaver B had greater amounts of the cytokines MMP-1 (3741 vs. 5500 pg/mL; p < 0.001), MMP-3 (1131 vs. 1871 pg/mL; p < 0.001), and MMP-13 (179 vs. 401 pg/mL; p < 0.001), while those collected with Shaver A had greater vascular endothelial growth factor (VEGF) (47.8 vs. 9.0 pg/mL; p < 0.05). Arthroscopic shavers are capable of harvesting and processing CTP cells from subacromial bursal tissue. Different shavers may produce different yields of viable CTP cells.

Clinical Outcomes following Biologically Enhanced Demineralized Bone Matrix Augmentation of Complex Rotator Cuff Repair.

Complex rotator cuff tears provide a significant challenge for treating surgeons, given their high failure rate following repair and the associated morbidity. The purpose of this study is to evaluate the clinical outcomes of patients who underwent biologically enhanced demineralized bone matrix augmentation of rotator cuff repairs. Twenty patients with complex rotator cuff tears underwent arthroscopic rotator cuff repair by a single surgeon with demineralized bone matrix (DBM) augmentation that was biologically enhanced with platelet-rich plasma and concentrated bone marrow aspirate. Post-operative MRI was used to determine surgical success. Patient reported outcome measures and range of motion data were collected pre-operatively and at the final post-operative visit for each patient. Ten patients (50%) with DBM augmentation of their arthroscopic rotator cuff repair were deemed non-failures. The failure group had less improvement of visual analogue pain scale (p = 0.017), Simple Shoulder Test (p = 0.032), Single Assessment Numerical Evaluation (p = 0.006) and abduction (p = 0.046). There was no difference between the groups for change in American Shoulder and Elbow Society score (p = 0.096), Constant-Murley score (p = 0.086), forward elevation (p = 0.191) or external rotation (p = 0.333). The present study found that 50% of patients who underwent biologically enhanced DBM augmentation of their rotator cuff repair demonstrated MRI-determined failure of supraspinatus healing.

Inpatient versus outpatient shoulder arthroplasty outcomes: A propensity score matched risk-adjusted analysis demonstrates the safety of outpatient shoulder arthroplasty.

OBJECTIVES: Beginning January 1, 2021 total shoulder arthroplasty (TSA) was removed from the Medicare (U.S national healthcare for patients ≥ 65years of age) inpatient-only list. Furthermore, there is limited data comparing outpatient and inpatient TSA among recent contemporary large population databases. This study aimed to analyze shoulder arthroplasty outcomes between inpatient and outpatient procedures at the national level. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was utilized (2015-2019). Cases with a current procedural terminology of 23472 indicative of primary TSA and reverse total shoulder arthroplasty were included (N = 22,452). Outcomes were then analyzed in two approaches: unmatched analysis and propensity score matched risk-adjusted analysis. RESULTS: Overall, 9.7% (N = 2,185) of cases were performed outpatient and 90.3% (N = 20,357) of cases were performed inpatient. The rate of outpatient procedures has been steadily increasing (2015: 8.3%, 2016: 14.7%, 2017: 15.8%, 2018: 26.5%, 2019: 34.6%; P < 0.001). Outpatients were more likely to be male (50.7% vs. 43.7%) and younger (age < 65; 37.0% vs. 27.9%) and less likely to be ASA class 3 or 4 (49.5% vs. 58.3%). Outpatients had fewer comorbidities including obesity (46.1% vs. 51.9%), hypertension (60.5% vs. 67.4%), diabetes (15.1 vs. 18.2%), chronic obstructive pulmonary disease (4.8% vs. 7.0%), bleeding disorders (1.3% vs. 2.5%), or chronic steroid use (3.5% vs. 5.0%; all P < 0.001). In a non-risk matched analysis of outcomes, outpatient procedures displayed lower rates of any adverse event (3.5% vs. 5.3%; P < 0.001), minor adverse events (1.5% vs. 3.0%; P = 0.001), and readmission (2.2% vs. 2.8%; P = 0.025). Following a propensity score matched analysis, two risk matched cohorts of outpatient (N = 2,172) and inpatient (N = 2,172) procedures were identified. Subsequent analysis of outcomes revealed no significant differences in outcome metrics between risk-matched outpatient and inpatient procedures. CONCLUSIONS: From 2015 to 2019, there has been a four-fold increase in the proportion of outpatient shoulder arthroplasty cases in the ACS-NSQIP database. This study shows that outpatient shoulder arthroplasty may be safely performed in a select cohort of patients without increased risk of adverse events. After adjusting for comorbidities, there were no differences in clinical outcomes or rates of adverse outcomes between inpatient and outpatient shoulder arthroplasty. LEVEL OF EVIDENCE: Retrospective Observational Study, Level IV.

The Role of the Trapezius in Stabilization of the Acromioclavicular Joint: A Biomechanical Evaluation.

Background: Acromioclavicular joint (ACJ) injuries are common, and many are adequately treated nonoperatively. Biomechanical studies have mainly focused on static ligamentous stabilizers. Few studies have quantified ACJ stabilization provided by the trapezius. Purpose/Hypothesis: To elucidate the stabilization provided by the trapezius to the ACJ during scapular internal and external rotation (protraction and retraction). It was hypothesized that sequential trapezial resection would result in increasing ACJ instability. Study Design: Controlled laboratory study. Methods: A biomechanical approach was pursued, with 10 cadaveric shoulders with the trapezius anatomically force loaded to normal. The trapezius was then serially transected over 8 trials, which alternated between clavicular defects (CD) and scapular defects (SD); each sequential defect consisted of 25% of the clavicular or scapular trapezial attachment. After each defect, specimens were tested with angle-controlled scapular internal and external rotation (12°) with rotary torque measurements to evaluate ACJ stability. Results: The mean resistance in rotary torque for 12° of scapular internal rotation (protraction) with native specimens was 7.0 ± 2.0 N·m. Overall, internal rotation demonstrated a significant decrease in ACJ stability with trapezial injury (P < .001). Eight sequential defects resulted in the following significant percentage decreases in rotary torque from native internal rotation: 1.5% (25% CD; 0% SD), 5.6% (25% CD; 25% SD), 5.1% (50% CD; 25% SD), 6.5% (50% CD; 50% SD), 3.8% (75% CD; 50% SD), 7.1% (75% CD; 75% SD), 6.7% (100% CD; 75% SD), and 12.3% (100% CD 100% SD) (P < .001). The mean resistance in rotary torque for 12° of scapular external rotation (retraction) with native specimens was 7.1 ± 1.7 N·m. External rotation did not demonstrate a significant decrease in ACJ stability with trapezial injury (P = .596). The 8 sequential defects resulted in decreases in rotary torque from native external rotation of 0%, 3.8%, 4.0%, 3.2%, 3.5%, 3.4%, 4.2%, and 0.7%. Conclusion: Trapezial injury resulted in increased instability in the setting of scapular internal rotation (protraction) of the ACJ. Clinical Relevance: These findings validate the inclusion of deltotrapezial fascial injury consideration in the modified Rockwood classification system. Repair of the trapezial insertion on the ACJ may provide improved outcomes in the setting of ACJ reconstruction.

Venous thromboembolism complications in shoulder surgery: current concepts.

Venous thromboembolism (VTE) is a rare yet known complication of shoulder surgery. Concerning shoulder arthroplasty, reported rates of VTE range from 0.2% to 16%. Unlike many lower extremity procedures, particularly total hip and knee arthroplasty, chemical prophylactic guidelines for VTE in shoulder surgeries have not been established. Some argue that doing so is unnecessary. On the contrary, mechanical prophylaxis is nearly universally accepted in shoulder surgery, particularly for more lengthy procedures. With limited VTE incidence in shoulder surgery, treatment is anecdotally derived from the hip and knee arthroplasty literature. Recent studies have successfully identified risk factors for VTE related to the patient and to the surgery itself. Awareness of these risk factors by the surgeon and declaration of these factors to the patient should be discussed as part of the informed consent process. Further investigational studies and larger patient cohorts will be necessary to optimise VTE prevention in shoulder surgeries.