bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predictors of Outcomes after Arthroscopic Double-row Rotator Cuff Repair in 155 Cases
Authors: Katthagen Jan Christoph , Millett Peter J. , Espinoza-Ervin Christopher , Horan Marilee P. , Ho Charles P. , Warth Ryan J. , Dornan Grant 
Published: July 2016

Objectives: The purpose of this study was to analyze predictors of clinical outcomes of knotted versus knotless double-row self-reinforcing rotator cuff repairs of full-thickness rotator cuff tears with propensity score matching. Methods: Patients with arthroscopic repair of full-thickness rotator cuff tears involving the supraspinatus tendon using either a knotted or knotless linked, self-reinforcing double-row technique were included in the study. Preoperative subjective evaluation was performed using the ASES and SF-12 PCS scores. After a minimum two-year follow-up period, ASES and SF-12 PCS scores were collected again along with the SANE score, the QuickDASH score, and patient satisfaction. All data were collected prospectively and retrospectively reviewed. Postoperative ASES and SF-12 PCS scores were then modeled using inverse propensity score weighting in a multiple linear regression model (MLR) with multiple imputations. Age, sex, baseline ASES score, length of follow-up, number of anchors, worker’s compensation, previous cuff repair, and double-row repair technique (knotted or knotless) were the covariates used in this model. Results: 155 shoulders in 151 patients (109 men, 42 women; mean age at time of surgery 59±10 years) were eligible for inclusion. Outcomes data were available for 130 of 148 shoulders (87.8%) after exclusion of seven shoulders (4.5%) that underwent revision rotator cuff repair before final follow up (n=33/39 in the knotted group [84.6%]; n=97/109 [88.9%] in the knotless group).The mean follow-up was 2.9 years (range, 2.0-5.4 years). Overall, postoperative outcomes scores were significantly improved when compared to preoperative baselines (p<0.05), with a median postoperative ASES score of 97 for the entire cohort. Our model showed that previous rotator cuff repair had a significant negative effect on postoperative ASES (β = -12.7, p<0.001) and SF-12 PCS scores (β = -5.0, p = 0.036). A workers’ compensation claim (β = -10.6, p = 0.007) also had a significant negative effect on postoperative ASES scores. Higher baseline ASES score (β = +0.14, p = 0.025) positively influenced ASES outcomes. Use of a knotless technique also had a positive effect on postoperative scores (β = +2.5, p = 0.235). Age, gender, the length of follow-up and the numbers of anchors did not influence the outcomes (Table 1). Conclusion: Excellent clinical outcomes can be achieved a minimum of two years following arthroscopic repair of full-thickness rotator cuff tears using either the knotted or knotless linked double-row technique. Negative predictors of outcome include low preoperative ASES score, previous rotator cuff repair, and a workers’ compensation claim. Knotless double-row rotator cuff repair had a non-significantly positive effect on the postoperative ASES score compared to the knotted double-row suture bridge technique.
Pharmacological Inhibition of Myostatin Protects Against Atrophy and Weakness after ACL Tear
Authors: Wolfe Caroline Nicole , Gumucio Jonathan P. , Grekin Jeremy , Khouri Roger Karl , Bedi Asheesh , Mendias Christopher 
Published: July 2016

Objectives: Many patients who suffer ACL tears have persistent atrophy and weakness even after rehabilitation. Myostatin is a cytokine that directly induces muscle atrophy, and previous studies using rodent models and patients have demonstrated an up regulation of myostatin after ACL tear. Using a preclinical rat model, our objective was to determine if the use of a bioneutralizing antibody against myostatin could prevent muscle atrophy and weakness after ACL tear. Methods: This study was approved by our IACUC. The left ACL and was transected in 3mo-old male F344 rats. At the time of surgery rats received a single IP injection of either a bioneutralizing antibody against myostatin (10B3, GlaxoSmithKline) or a sham IgG (E1-82.15, GlaxoSmithKline) at a dose of 10mg/kg. Rats (N=8 per group) were sacrificed and tissue was harvested 7 days or 21 days after tear. Contractile force measurements of the extensor digitorum longus (EDL) were performed. The size of muscle fibers in histological sections from the EDL and distal vastus lateralis were also measured. RNA was isolated from the distal rectus femoris and gene expression analysis was performed with RT-qPCR. The expression of each gene was normalized to b actin, and further normalized to the expression of muscles from control, uninjured rats. A two-way ANOVA (alpha=0.05) followed by Holm Sidak post hoc sorting was used to evaluate the effect of time and treatment on measured parameters. Results: Inhibition of myostatin resulted in an increase in muscle fiber size at the 21D time point compared to all other groups (Table 1). While both the sham antibody and myostatin antibody groups increased maximum isometric force production from 7D to 21D, the myostatin antibody group at 21D had a further increase in force compared to the 21D sham group. The muscle E3 ubiquitin ligases atrogin-1 and muscle ring finger 1 (MuRF-1) are the major rate limiting enzymes in muscle protein degradation, and inhibition of myostatin resulted in decreases in the expression of these genes at 7D (Figure 1A). Additionally, IGF-1Ea and IGF-1Eb which are important growth factors that induce muscle protein synthesis, were elevated in the myostatin antibody groups at the 21D time point. For genes related to fibrosis (Figure 1B), although there was no significant difference in MMP-2, there was a significant decrease of MMP-8 expression in the 21D MSTN group when compared to the 21D sham. There were also increases in the expression of TIMP-1 and 2 in the 21D MSTN group. Conclusion: In a preclinical rat model, the targeted inhibition of myostatin protected leg muscles from muscle atrophy and improved force production after ACL tear. While the mechanism of action is not entirely clear, it is possible that the inhibition of myostatin preserves strength by limiting the expression of proteolytic enzymes in the post-acute atrophy phase and increasing protein synthesis in later phases.
Biomarker Changes in ACL Deficient Knees Compared with Contralaterals
Authors: Strauss Eric Jason , Kaplan Daniel James , Jazrawi Laith M. 
Published: July 2016

Objectives: Introduction: Though outcomes following ACL reconstruction are largely positive, patients’ post-operative recovery is highly variable, and is typically based off generalized timetables derived from population data. In an attempt to individualize prognostic estimates and establish how biomarker concentrations may change with injury, we sampled knee joint synovial fluid from patients with ACL tears with and without associated cartilage injuries and compared biomarker concentrations to samples obtained from the contralateral non-injured knee. Methods: 480 patients indicated for knee arthroscopy had samples drawn to form a synovial fluid database. If no injury history or symptoms were present in the contralateral knee, samples were drawn as well. For the current study, only patients that had confirmed ACL injury at the time of arthroscopy were included. Associated cartilage injury location, size and depth was documented. Synovial fluid samples were centrifuged, and the concentrations of 20 biomarkers were determined using a multiplex magnetic bead immunoassay. Concentrations were then compared between the three study groups (ACL tear with cartilage injury, ACL tears without cartilage injury, and healthy contralateral knees) using a Welch ANOVA test with pairwise comparisons. Results: The study included samples from 132 knees: 34 ACL tears without cartilage injury (mean age 34.0 years); 28 ACL tears with cartilage injury (mean age 36.3 years), and 72 contralateral knees (41.1 years). ANOVA testing demonstrated significant differences among groups for: MMP-3 (p>001); TIMP-1 (p=.001); TIMP-2 (p=.015); FGF-2 (p=.011); IL-6 (p=.001); and MIP-1b (p=.001). Pairwise comparisons demonstrated no significant differences between ACL tears with, and without cartilage damage, but did show both types of ACL tears had significantly higher concentrations of MMP-3, TIMP-1, IL-6, and MIP-1b than contralaterals. ACL tears without cartilage damage had significantly lower concentrations of TIMP-2 and FGF-2 (13) than contralaterals (Table 1). Conclusion: The course from surgery to symptomatic relief and functional improvement following ACL reconstruction is highly variable. Data from the current study demonstrated that cytokine concentrations are significantly different between ACL tears (+/- cartilage damage) and healthy knees. These validated differences can help establish synovial fluid biomarker analysis as a method for injury stratification ultimately providing patient-specific prognostic data.
Engaging Hill-Sachs Defects
Authors: Burns David , Chahal Jaskarndip , Shahrokhi Shahram , Henry Patrick , Wasserstein David , Whyne Cari , Theodoropoulos John S. , Ogilvie-Harris Darrell , Dwyer Tim 
Published: July 2016

Objectives: Anatomic studies have demonstrated that bipolar glenoid and humeral bone loss have a cumulative impact on shoulder instability, and that these defects may engage in functional positions depending on their size, location, and orientation, potentially resulting in failure of stabilization procedures. Determining which lesions pose a risk for engagement remains a challenge, with arthroscopic assessment and Itoi’s 3DCT based glenoid track method being the accepted approaches at this time. The purpose of this study was to investigate the interaction of humeral and glenoid bone defects on shoulder engagement in a cadaveric model. Two alternative approaches to predicting engagement were evaluated; 1) CT scanning the shoulder in abduction and external rotation 2) measurement of Bankart lesion width and a novel parameter, the intact anterior articular angle (IAAA), on conventional 2D multi-plane reformats. The results of these two approaches were compared to the results obtained using Itoi’s glenoid track method for predicting engagement. Methods: Hill-Sachs and Bony Bankart defects of varying size were created in 12 cadaveric upper limbs, producing 45 bipolar defect combinations. The shoulders were assessed for engagement using cone beam CT in various positions of function, from 30 to 90 degrees of both abduction and external rotation. The humeral and glenoid defects were characterized by measurement of their size, location, and orientation. Diagnostic performance measures for predicting engagement were calculated for both the abduction external rotation scan and 2D IAAA approaches using the glenoid track method as reference standard. Results: Engagement was predicted by Itoi’s glenoid track method in 24 of 45 specimens (53%). The abduction external rotation CT scan performed at 60 degrees of glenohumeral abduction (corresponding to 90 degrees of abduction relative to the trunk) and 90 degrees of external rotation predicted engagement accurately in 43 of 45 specimens (96%), with sensitivity and specificity of 92% and 100% respectively. A logistic model based on Bankart width and IAAA provided a prediction accuracy of 89% with sensitivity and specificity of 91% and 87%. Inter-rater agreement was excellent (Kappa = 1) for classification of engagement on the abduction external rotation CT, and good (intraclass correlation = 0.73) for measurement of IAAA. Conclusion: Bipolar lesions at risk for engagement can be identified using an abduction external rotation CT scan at 60 degrees of glenohumeral abduction and 90 degrees of external rotation, or by performing 2D measurements of Bankart width and IAAA on conventional CT multi-plane reformats. This information will be useful for decision making in the setting of bipolar bone defects prior to shoulder stabilization.
MRI Abnormalities Are Common In Little League Player’s Elbows
Authors: Pennock Andrew T. , Roocroft Joanna Helena , Bastrom Tracey P. , Kruk Peter 
Published: July 2016

Objectives: Youth baseball is extremely popular, but it has been associated with elbow pain and pathology. The purpose of this study was to examine pre- and post-season Magnetic Resonance Imaging (MRI) changes in Little League baseball players and correlate these findings with the players’ throwing history and physical exams. Methods: A prospective study of Little League players age 10 -13 years was performed. Players were recruited prior to the start of the season and underwent bilateral elbow MRI. All players underwent a physical exam and responded to a questionnaire addressing their playing history and arm pain. At the end of the season, the players underwent repeat physical exam and MRI of their throwing arm. MRIs were read by two blinded radiologists. During the season, player statistics including innings played and pitch counts were recorded. Physical exam findings and players statistics were compared between subjects with and without MRI changes utilizing chi-square and ANOVA techniques. Results: Twenty-six players were enrolled. On pre-season MRI, nine players (35%) had 12 positive MRI findings; edema of the medial epicondyle (ME) apophysis (7), fragmentation of ME (2), and edema of the sublime tubercle (3). The two factors associated with a positive MRI were year round play (47% vs 11%, p<0.01) and working with a private coach (71% vs 21%, p=0.02). A history of pain was also associated with year round play and a private coach (p<0.05). Loss of internal rotation was associated with an abnormal MRI (p = 0.04). Post-season, 25 players returned for follow-up. Ten players (40%) had an abnormal MRI of which 8 (32%) had new/worsening findings. There was a significant difference in distal humeral physeal width measured pre- to post-season (1.54 mm vs 2.31 mm p<0.001). There was a significant decrease in internal rotation measured pre- to post-season of the shoulder in all patients regardless of MRI findings (62° vs 43°, p=0.001). Pitch counts, player position, and throwing curve balls/sliders were not significantly associated with pain or MRI abnormality post season (p >0.10). Descriptively, 60% of self-reported pitchers/catchers had post season MRI findings versus 40% of other field positions (p=0.3). Conclusion: Pre-season and post-season MRI abnormalities of the medial elbow are common in Little League baseball players. While Little League pitching guidelines are intended to decrease overuse injuries, our data indicate that further refinement of these guidelines addressing year round play, pain and private coaching should be considered.
3-D Computed Tomography (CT) Comparison Of The Pre-injury And Post-repair Syndesmosis To Assess Anatomic Reduction
Authors: Turnbull Travis L. , Schon Jason , Williams Brady T. , Venderley Melanie , Dornan Grant , Backus Jonathon D. , LaPrade Robert F. , Clanton Thomas O. 
Published: July 2016

Objectives: Historically, unstable injuries to the distal tibiofibular syndesmosis have been repaired with syndesmotic screws. However, newer repair techniques with inherently flexible implants, including suture-button constructs, may be less susceptible to malreduction and more reliably restore the native anatomy. The purpose of this study was to compare the anatomic accuracy of reduction between a syndesmotic screw and suture-button constructs for syndesmosis repair using a pre-injury and postoperative 3-D model assessment. We hypothesized significant differences would be observed among repair techniques and suture-button constructs would most accurately restore the pre-injury syndesmotic volume. Methods: Twelve matched pairs of cadaveric specimens were dissected to identify the syndesmotic ligaments. Specimens were imaged with CT prior to the creation of a complete syndesmosis injury. The disrupted syndesmosis of each specimen was subsequently reduced using one of three randomly assigned repair techniques: (1) tri-cortical syndesmosis screw (3.5 x 50 mm), (2) one suture-button construct and (3) two suture-button constructs. Specimens were imaged postoperatively with CT. 3-D models of all scans and tibiofibular joint space volumes were created to assess restoration of the native syndesmosis (Figure 1). Volumetric joint space measurements were made starting at the distal aspect of the tibiofibular articulation and extended proximally with four 1 cm sections measured separately. Results: For each of the three fixation methods, the adjusted least squares means for total post-operative volumes of the syndesmosis were significantly decreased relative to the intact state. Total overall decreases in volume compared to the intact state for the one suture-button construct, two suture-button constructs, and syndesmotic screw were -561mm3, -964mm3, and -377mm3, respectively. Fixation with one suture-button construct was not significantly different from screw or two suture-button fixations. However, the total decrease in volume was significantly greater with the two suture-button repair compared to screw fixation ( p < .05). Conclusion: The most important finding of this study was that fixation with one suture-button construct was not significantly different from screw or two suture-button fixations. All repairs significantly reduced the volume of the syndesmosis postoperatively compared to the intact state. Fixation with two suture-buttons resulted in significantly greater decreased volume than screw fixation. The data from the present study suggests that syndesmotic over-compression at time zero, particularly when using multiple suture-button implants, may be another potential factor contributing to malreduction of syndesmosis injuries that deserves further investigation.
Differences in Acetabular Rim Thickness in Patients with Unilateral Symptomatic Pincer-Type Femoroacetabular Impingement
Authors: Weber Alexander E. , Kuhns Benjamin , Cvetanovich Gregory , Inoue Nozomu , Nho Shane Jay 
Published: July 2016

Objectives: The objective of this study was to identify the location and magnitude of difference in acetabular rim morphology between the symptomatic and asymptomatic acetabula in a cohort of patients with symptomatic unilateral pincer-type FAI. Methods: After IRB approval, computed tomography (CT) scans of 43 patients (22 males, 21 females) diagnosed with unilateral pincer-type FAI were obtained. CT images of both hips were imported in DICOM format and segmented into 3-dimensional (3D) hemi-pelvises using 3D reconstruction software (Mimics, Materialise, Leuven, Belgium). The point-cloud data of the asymptomatic hemi-pelvis was mirrored onto the symptomatic side. Protrusion of the symptomatic side was recorded as a positive value and appeared as red on the color map (Figure 1). Data was collected in 3° intervals and analyzed by quadrant using the clock face method; reflecting the 12-3, 3-6, 6-9, and 9-12 o’clock positions. Results: The symptomatic acetabular rim was on average 0.39 ± 0.36 mm thicker than the corresponding location on the asymptomatic rim. When the acetabular clock face was broken up into quadrants, reflecting the 12-3, 3-6, 6-9, and 9-12 o’clock positions, the 12-3 o’clock position demonstrated the greatest difference between symptomatic and asymptomatic sides (Table 1). The 12-3 o’clock quadrant demonstrated significantly greater difference between symptomatic and asymptomatic sides (0.53±0.22 mm) as compared to the 3-6 o’clock position (0.39±0.27 mm; p=0.006), the 6-9 o’clock position (0.34±0.05 mm; p<0.001), and the 9-12 o’clock position (0.33±0.03; p<0.001). There was no correlation between gender and magnitude of difference at any location. Conclusion: Small changes in acetabular rim morphology, on the order of 0.5 mm or less can be the difference between symptomatic pincer-type FAI and the asymptomatic state. Knowledge of the healthy, unaffected side in unilateral FAI may provide a better template for rim recession rather than broadly applying previously described anterior or lateral center-edge angle parameters.
The Effect of Purified Multi-potent Human Bone-marrow Derived Mesenchymal Stem Cells on Rotator Cuff Tendon Healing in an Athymic Rat
Authors: Degen Ryan , Carbone Andrew , Carballo Camilia , Zong Jianchun , Chen Tony , Ying Lilly , Lebaschi Amir , Deng Xiang-Hua , Rodeo Scott A. 
Published: July 2016

Objectives: Bone marrow concentrates are being used to augment soft tissue healing. However, only 0.01% of these cells meet the criteria of a mesenchymal stem cell (MSC), which likely accounts for the variability in reported results. Previous studies using an established rat rotator cuff repair model have demonstrated that bone marrow-derived MSCs had no effect on healing. In this study we evaluated the effect of purified human MSCs on rotator cuff healing in an athymic rat model. Our hypothesis is that purified human MSCs added to the repair site will improve biomechanical strength and fibrocartilage formation of the healing tendon. Methods: Fifty-two athymic rats underwent unilateral detachment and repair of the supraspinatus tendon with either fibrin glue (control) or fibrin glue with 106 hMSCs (experimental) applied at the repair site. Flow cytometry verified the stem cell phenotype of the cells as CD73+, CD90+, CD105+, CD 14-, CD34- and CD45-. Rats were sacrificed at 2 and 4 weeks, with 10 used for biomechanical testing and 3 for histologic analysis from each group. Results: Biomechanical testing revealed a significant increase in failure load (11.5±2.4 N vs. 8.5±2.4 N, p=0.002) and stiffness (7.1±1.2 N/mm vs. 5.7±2.1 N/mm, p&gt0.17).Biomechanical testing revealed a significant increase in failure load (11.5±2.4 N vs. 8.5±2.4 N, p=0.002) and stiffness (7.1±1.2 N/mm vs. 5.7±2.1 N/mm, p&lt0.001) in the experimental group compared with the control group at 2 weeks. Similarly, safranin-O staining identified increased fibrocartilage formation at the repair site at 2 weeks in the hMSC group (18.6±2.9% vs. 9.1±1.6%, p=0.026). These effects dissipated by 4 weeks, with no significant biomechanical or histologic differences between groups (p&gt0.17). Conclusion: These data demonstrate the potential for stem cells to augment tendon healing. This is the first study to use purified stem cells, rather than simple bone marrow concentrate. In the future, cell sorting techniques and culture expansion could be used to select and expand the small population of true stem cells in bone marrow. Furthermore, healing could potentially be improved with repeat cell injection at an additional post-operative time point. Application of hMSCs represents a potential solution for improving rotator cuff healing following repair. Further study is necessary to determine the clinical applicability of these results.