Predictive modeling of ambulatory outcomes after spinal cord injury using machine learning.

STUDY DESIGN: Retrospective multi-site cohort study. OBJECTIVES: To develop an accurate machine learning predictive model using predictor variables from the acute rehabilitation period to determine ambulatory status in spinal cord injury (SCI) one year post injury. SETTING: Model SCI System (SCIMS) database between January 2000 and May 2019. METHODS: Retrospective cohort study using data that were previously collected as part of the SCI Model System (SCIMS) database. A total of 4523 patients were analyzed comparing traditional models (van Middendorp and Hicks) compared to machine learning algorithms including Elastic Net Penalized Logistic Regression (ENPLR), Gradient Boosted Machine (GBM), and Artificial Neural Networks (ANN). RESULTS: Compared with GBM and ANN, ENPLR was determined to be the preferred model based on predictive accuracy metrics, calibration, and variable selection. The primary metric to judge discrimination was the area under the receiver operating characteristic curve (AUC). When compared to the van Middendorp all patients (0.916), ASIA A and D (0.951) and ASIA B and C (0.775) and Hicks all patients (0.89), ASIA A and D (0.934) and ASIA B and C (0.775), ENPLR demonstrated improved AUC for all patients (0.931), ASIA A and D (0.965) ASIA B and C (0.803). CONCLUSIONS: Utilizing artificial intelligence and machine learning methods are feasible for accurately classifying outcomes in SCI and may provide improved sensitivity in identifying which individuals are less likely to ambulate and may benefit from augmentative strategies, such as neuromodulation. Future directions should include the use of additional variables to further refine these models.

Improved Functional Outcomes of Combined Hip Arthroscopy and Periacetabular Osteotomy at Minimum 2-Year Follow-Up.

PURPOSE: To evaluate patient-reported outcomes (PROs) and survivorship at minimum 2-year follow-up after combined hip arthroscopy and periacetabular osteotomy (PAO) performed in the setting of a single anesthetic event. METHODS: Patients who underwent combined hip arthroscopy (M.J.P.) and PAO (J.M.M.) between January 2017 and June 2020 were identified. Preoperative and minimum 2-year postoperative PROs including Hip Outcome Score-Activities of Daily Living (HOS-ADL), HOS-Sport, modified Harris Hip Score (mHHS), Western Ontario and McMaster Universities Osteoarthritis Index, 12-Item Short Form Survey Mental Component Scores (SF-12 MCS), and 12-Item Short Form Survey Physical Component Score were collected and compared in addition to revision rate, conversion to total hip arthroplasty (THA), and patient satisfaction. RESULTS: Twenty-four of 29 patients (83%) eligible for the study were available for 2-year minimum follow-up with a median follow-up time of 2.5 years (range, 2.0-5.0). There were 19 females and 5 males with mean age of 31 ± 12 years. Mean preoperative lateral center edge angle was 20° ± 5° and alpha angle was 71° ± 11°. One patient underwent reoperation for removal of a symptomatic iliac crest screw at 11.7 months after operation. Two patients, a 33-year-old woman and a 37-year-old man, were converted to THA at 2.6 and 1.3 years, respectively, following the combined procedure. Both patients had a Tönnis grade of 1 on radiographs, as well as bipolar Outerbridge grade III/IV defects requiring microfracture of the acetabulum. For patients who did not convert to THA (n = 22), there was significant improvement from before to after surgery for all scores (P < .05) except SF-12 MCS. The minimal clinically significant difference and patient-acceptable symptom state rates for HOS-ADL, HOS-Sport, and mHHS were 72%, 82%, 86%, and 95%, 91%, and 95%, respectively. Median patient satisfaction was 10 (range, 4 to 10). CONCLUSIONS: Single-stage combined hip arthroscopy with periacetabular osteotomy for patients with symptomatic hip dysplasia results in improvement in PROs and arthroplasty free survivorship of 92% at median 2.5 year follow-up. LEVEL OF EVIDENCE: Level IV, case series.

Preoperative patient factors that predict achieving the minimal clinically important difference following arthroscopic treatment of snapping scapula syndrome.

BACKGROUND: The aim of this study was to define the minimal clinically important difference (MCID) values for patient-reported outcomes (PROs) after arthroscopic treatment of snapping scapula syndrome (SSS) using a distribution-based method, and to identify demographic, clinical, and intraoperative factors significantly associated with the achievement of MCID. It was hypothesized that subjective satisfaction scores after the procedure would be strongly associated with the achievement of MCID thresholds for the PROs and that pain, preoperative response to injection, and a scapulectomy in addition to bursal resection would be predictive of clinically relevant improvement. METHODS: Patients who underwent arthroscopic treatment of SSS between October 2005 and September 2020 with a minimum of 2-year short-term postoperative follow-up were enrolled in this retrospective single-center study. The MCID was calculated using a distribution-based approach for the following PROs: 12-Item Short Form Health Survey (SF-12), American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), Quick Disabilities of the Arm, Shoulder, and Hand questionnaire (QuickDASH), Single Assessment Numeric Evaluation (SANE), and visual analog scale (VAS) pain "today" and "at worst." The association between achievement of the MCID and postoperative subjective satisfaction was investigated, and factors associated with achievement of MCID were determined using bivariate analysis. RESULTS: Of a total of 190 patients assessed for eligibility, 77 patients (38.1 ± 14.3 years; 36 females) were included. Within the study population, statistically significant improvements in postoperative SF-12 physical component summary (PCS) (P < .001) and mental component summary (MCS) (P < 0.034), ASES (P < .001), QuickDASH (P < .001), SANE (P < .001), and VAS pain (P < .001) scores were observed at the minimum 2-year follow-up. The calculated MCID threshold values based on the study population were 5.0 for SF-12 PCS, 5.8 for SF-12 MCS, 11.3 for ASES, -10.5 for QuickDASH, 14.7 for SANE, 1.5 for VAS pain, and 1.7 for VAS pain at worst. Reaching the MCID was strongly associated with postoperative satisfaction (rated on a scale of 1-10). Across the PROs, younger age, favorable preoperative response to injection, partial scapuloplasty or scapulectomy, no prior surgery, and pain and function at baseline were significantly associated with attaining MCID. CONCLUSIONS: Patients who underwent arthroscopic treatment for SSS experienced clinically significant improvements in functional scores, pain, and quality of life. This study demonstrated predictive roles for certain patient-specific factors and diagnostic variables for achieving MCID in PROs, which may help surgeons preoperatively assess the probability of success and manage patient expectations.

Superior Capsule Reconstruction Using Acellular Dermal Allograft Secured at 45° of Glenohumeral Abduction Improves the Superior Stability of the Glenohumeral Joint in Irreparable Massive Posterosuperior Rotator Cuff Tears.

PURPOSE: The purpose of the current study was to create a dynamic cadaveric shoulder model to determine the effect of graft fixation angle on shoulder biomechanics following SCR and to assess which commonly used fixation angle (30° vs 45° of abduction) results in superior glenohumeral biomechanics. METHODS: Twelve fresh-frozen cadaveric shoulders were evaluated using a dynamic shoulder testing system. Humeral head translation, subacromial and glenohumeral contact pressures were compared among 4 conditions: 1) Intact, 2) Irreparable supra- and infraspinatus tendon tear, 3) SCR using acellular dermal allograft (ADA) fixation at 30° of abduction, and 4) SCR with ADA fixation at 45° of abduction. RESULTS: SCR at both 30° (0.287 mm, CI: -0.480 - 1.05 mm; P < .0001) and 45° (0.528 mm, CI: -0.239-1.305 mm; P = .0006) significantly decreased superior translation compared to the irreparably torn state. No significant changes in subacromial peak contact pressure were observed between any states. The average glenohumeral contact pressure increased significantly following creation of an irreparable RCT (373 kPa, CI: 304-443 vs 283 kPa, CI 214-352; P = .0147). The SCR performed at 45° (295 kPa, CI: 226-365, P = .0394) of abduction significantly decreased the average glenohumeral contact pressure compared to the RCT state. There was no statistically significant difference between the average glenohumeral contact pressure of the intact state and SCR at 30° and 45°. CONCLUSION: SCR improved the superior stability of the glenohumeral joint when the graft was secured at 30° or 45° of glenohumeral abduction. Fixation at 45° of glenohumeral abduction provided more stability than did fixation at 30°. CLINICAL RELEVANCE: Grafts attached at 45° of glenohumeral abduction biomechanically restore the glenohumeral stability after SCR using ADA better than fixation at 30° of glenohumeral abduction.

Preventing varus collapse in proximal humerus fracture fixation: 90-90 dual plating versus endosteal fibular allograft strut.

INTRODUCTION: Screw cut out and varus collapse are the most common complication of locked plate fixation of proximal humerus fractures. The purpose of this study was to compare dual plating and endosteal fibular allograft struts as augmentation strategies to prevent varus collapse. MATERIALS AND METHODS: A trapezoidal osteotomy was created at the metaphysis to create a 2-part proximal humerus model in 18 paired shoulder specimens. Each specimen was assigned to group A, B, or C and was fixed with either a lateral locking plate, a lateral locking plate and anterior one-third tubular plate in an orthogonal 90/90 configuration, or a lateral locking plate with intramedullary fibular strut, respectively. The specimens were stressed in axial compression to failure. Displacement, elastic limit, ultimate load, and stiffness were recorded and calculated. RESULTS: There was no difference in mean cyclic displacement between the three groups (0.71 mm vs 0.89 mm vs 0.61 mm for Group A, B, C, respectively). Lateral plating demonstrated the greatest absolute and relative displacement at the elastic limit (5.3 mm ± 1.5 and 4.4 mm ± 1.3) without significance. The elastic limit or yield point was greatest for fibular allograft, Group C (1223 N ± 501 vs 1048 N ± 367 for Group B and 951 N ± 249 for Group A) without significance. CONCLUSIONS: Dual plating of proximal humerus fractures in a 90-90 configuration demonstrates similar biomechanical properties as endosteal fibular strut allograft. Both strategies demonstrate superior stiffness to isolated lateral locked plating.

Full thickness quadriceps tendon grafts with bone had similar material properties to bone-patellar tendon-bone and a four-strand semitendinosus grafts: a biomechanical study.

PURPOSE: Despite increasing interest in utilizing quadriceps tendon (QT) grafts in anterior cruciate ligament reconstruction (ACLR), data on the optimal quadriceps graft thickness are limited. The purpose of this study was to characterize the mechanical properties for the quadriceps tendon, comparing full-thickness (FT) QT grafts with and without bone to a partial-thickness (PT) QT graft, and comparing the three QT grafts to four-stranded semitendinosus (4-SST) and bone-patellar tendon-bone (BTB) grafts and one experimental graft, the two-stranded rectus femoris (RF). METHODS: Forty-eight (n = 48) young cadaveric grafts (mean age 32 ± 6 years) were utilized for testing with N = 8 specimens in each of the following groups; (1) FT QT with bone, (2) FT QT without bone, (3) PT QT without bone, (4) BTB, (5) RF, and (6) 4-SST. Each specimen was harvested and rigidly fixed in custom clamps to a dynamic tensile testing machine for biomechanical evaluation. Graft ultimate load and stiffness were recorded. Independent groups one-factor ANOVAs and Tukey's pairwise comparisons were performed for statistical analyses. RESULTS: FT QT with bone and 4-SST grafts demonstrated similar ultimate loads to BTB grafts (both n.s), whereas PT QT demonstrate statistically significantly lower ultimate loads to BTB grafts (n.s) and 4-SST grafts (n.s). Furthermore, no statistically significant differences were observed between the ultimate loads of FT QT vs. PT QT grafts without bone (n.s) or between FT QT with vs. without bone (n.s). FT QT grafts with bone did not demonstrate statistically significantly greater ultimate loads than PT QT grafts without bone (n.s). The RF graft demonstrated statistically significantly lower ultimate loads to BTB grafts (p < 0.005) and 4-SST grafts (p < 0.014). CONCLUSIONS: Full thickness QT grafts with bone had similar material properties to BTB and a 4-SST grafts, while Partial thickness QT graft without bone had significantly lower material properties than BTB and 4-SST, in a biomechanical setting.

Tibial Slope Can Be Maintained During Medial Opening-Wedge Proximal Tibial Osteotomy With Sagittally Oriented Hinge, Posterior Plate Position, and Knee Hyperextension: A Cadaveric Study.

PURPOSE: The purpose of this study is (1) to determine if, when optimizing modern techniques, medial opening-wedge osteotomies can effectively maintain tibial slope and (2) to determine how different magnitude coronal plane corrections affect tibial slope. METHODS: Proximal tibial osteotomies (PTOs) were performed on 10 fresh-frozen cadaveric knees leaving a consistent lateral hinge, using either a 5-mm or a 10-mm trapezoidal wedged osteotomy plate. Techniques including posterior plate placement; a trapezoidal, sloped plate; and knee hyperextension were used during plate fixation to help close the anterior osteotomy gap. Medial coronal proximal tibia angle and posterior tibial slope were measured preosteotomy, after a 5-mm implant, and after a 10-mm implant using true anteroposterior and lateral fluoroscopic images. Three independent observers performed all radiographic measurements, and intraclass correlation coefficients were calculated. RESULTS: The 5-mm and 10-mm osteotomy plates increased the coronal medial proximal tibia angle by a mean of 3.4° (range, 3.0°-3.7°) and 7.3° (range, 6.7°-7.7°), respectively. The 5-mm and 10-mm trapezoidal wedged osteotomy plates decreased the posterior tibial slope by a mean of 0.9° (range, 0.5°-1.2°) and 0.3° (range, 0°-0.6°), respectively. Intraobserver reliability was found to be high for both the coronal medial proximal tibia angle (intraclass correlation coefficient [ICC] = 0.897 [0.821-0.946]) and the tibial slope measurements (ICC = 0.761 [0.672-0.826]). CONCLUSIONS: When optimizing the medial opening-wedge proximal tibial osteotomy, including utilization of a sagittally oriented hinge, placement of a trapezoidal plate posteriorly, and fixation with knee hyperextension, posterior tibial slope can be maintained regardless of the degree of coronal correction. CLINICAL RELEVANCE: Tibial slope has a significant effect on cruciate ligament stress and a better understanding of coronal plane correction, and its effect on tibial slope is critical when performing proximal tibia osteotomies.

Beighton Score, Tibial Slope, Tibial Subluxation, Quadriceps Circumference Difference, and Family History Are Risk Factors for Anterior Cruciate Ligament Graft Failure: A Retrospective Comparison of Primary and Revision Anterior Cruciate Ligament Reconstructions.

PURPOSE: To assess patient history, physical examination findings, magnetic resonance imaging (MRI) and 3-dimensional computed tomographic (3D CT) measurements of those with anterior cruciate ligament (ACL) graft failure compared with primary ACL tear patients to better discern risk factors for ACL graft failure. METHODS: We performed a retrospective review comparing patients who underwent revision ACL reconstruction (ACLR) with a primary ACLR group with minimum 1-year follow-up. Preoperative history, examination, and imaging data were collected and compared. Measurements were made on MRI, plain radiographs, and 3D CT. Inclusion criteria were patients who underwent primary ACLR by a single surgeon at a single center with minimum 1-year follow-up or ACL graft failure with revision ACLR performed by the same surgeon. RESULTS: A total of 109 primary ACLR patients, mean age 33.7 years (range 15 to 71), enrolled between July 2016 and July 2018 and 90 revision ACLR patients, mean age 32.9 years (range 16 to 65), were included. The revision ACLR group had increased Beighton score (4 versus 0; P < .001) and greater side-to-side differences in quadricep circumference (2 versus 0 cm; P < .001) compared with the primary ACLR group. A family history of ACL tear was significantly more likely in the revision group (47.8% versus 16.5%; P < .001). The revision group exhibited significantly increased lateral posterior tibial slope (7.9° versus 6.2°), anterolateral tibial subluxation (7.1 versus 4.9 mm), and anteromedial tibia subluxation (2.7 versus 0.5 mm; all P < .005). In the revision group, femoral tunnel malposition occurred in 66.7% in the deep-shallow position and 33.3% in the high-low position. The rate of tibial tunnel malposition was 9.7% from medial to lateral and 54.2% from anterior to posterior. Fifty-six patients (77.8%) had tunnel malposition in ≥2 positions. Allograft tissue was used for the index ACLR in 28% in the revision group compared with 14.7% in the primary group. CONCLUSION: Beighton score, quadriceps circumference side-to-side difference, family history of ACL tear, lateral posterior tibial slope, anterolateral tibial subluxation, and anteromedial tibia subluxation were all significantly different between primary and revision ACLR groups. In addition, there was a high rate of tunnel malposition in the revision ACLR group.

Patient-reported drug and latex allergies negatively affect outcomes after total and reverse shoulder arthroplasty.

BACKGROUND: Patient-reported allergies (PRAs) have been identified as a risk factor for worse outcomes and less satisfaction in patients undergoing knee and hip arthroplasty. Similar associations have not been elucidated in shoulder arthroplasty patients; however, previous research is sparse. The purpose of this study was to assess the outcomes following shoulder arthroplasty surgery with respect to patient-reported drug allergies. It was hypothesized that a higher number of allergies would be associated with worse patient-reported outcomes (PROs) following shoulder arthroplasty surgery. METHODS: Consecutive patients aged 18-89 years at the time of surgery who underwent primary shoulder arthroplasty between October 2005 and March 2018 performed by a single surgeon and had a minimum follow-up period of 1 year were reviewed. PRO scores, including the American Shoulder and Elbow Surgeons score, Single Assessment Numerical Evaluation score, QuickDASH (short version of Disabilities of the Arm, Shoulder and Hand questionnaire) score, and 12-Item Short Form Health Survey Physical Component Summary and Mental Component Summary scores, as well as patient satisfaction, were collected preoperatively and postoperatively. Early clinical failures were reported. Subjects were categorized into a 3-level factor based on the number of PRAs (0, 1, or ≥2), and bivariate comparisons of mean postoperative PRO scores were performed using Kruskal-Wallis analyses. Additionally, multivariate regression was performed to assess the effect of PRAs on PROs while controlling for age, sex, arthroplasty type, baseline PRO scores, and Charlson Comorbidity Index. RESULTS: Overall, 411 shoulders were included in the final study population (367 patients, 44 of whom were treated bilaterally). The population was predominately male patients (n = 265, 64.5%), and the median age at the time of surgery was 66.5 years (first quartile-third quartile, 61.3-71.4 years). Of the patients, 253 (61.6%) underwent total shoulder arthroplasty (TSA) whereas 158 (38.4%) underwent reverse TSA. Five patients (2 TSA and 3 reverse TSA patients) experienced early clinical failure and required revision surgery. Minimum 1-year PROs were obtained for 345 of 406 patients (85.0%) with a mean follow-up period of 1.9 ± 1.2 years. Nearly all postoperative PROs reflected a trend of worse outcomes with more preoperative PRAs; however, the QuickDASH score was the only score showing a significant difference between allergy groups (P = .004). Pair-wise comparison using Nemenyi post hoc testing showed that the QuickDASH score was significantly higher (worse outcomes) for the group with ≥2 allergies compared with the group with 0 allergies. PRA was found to be a statistically significant predictor of higher postoperative QuickDASH scores (P = .043) and was more influential than the Charlson Comorbidity Index and sex. Additionally, PRA was the only statistically significant predictor of patient satisfaction (P = .016). CONCLUSION: An increasing number of preoperative PRAs is associated with worse PROs and patient satisfaction following shoulder arthroplasty. The number of PRAs was the most influential predictor of patient satisfaction.

Consensus statement on the treatment of massive irreparable rotator cuff tears: a Delphi approach by the Neer Circle of the American Shoulder and Elbow Surgeons.

BACKGROUND: Management of massive irreparable rotator cuff tears (MIRCTs) remains controversial owing to variability in patient features and outcomes contributing to a lack of unanimity in treatment recommendations. The purpose of this study was to implement the Delphi process using experts from the Neer Circle of the American Shoulder and Elbow Surgeons to determine areas of consensus regarding treatment options for a variety of MIRCTs. METHODS: A panel of 120 shoulder surgeons were sent a survey regarding MIRCT treatments including arthroscopic débridement and partial cuff repair, graft augmentation, reverse shoulder arthroplasty (RSA), superior capsular reconstruction (SCR), and tendon transfer. An iterative Delphi process was then conducted with a first-round questionnaire consisting of 13 patient factors with the option for open-ended responses to identify important features influencing the treatment of MIRCTs. The second-round survey sought to determine the importance of patient factors related to the 6 included treatment options. A third-round survey asked participants to classify treatment options for 60 MIRCT patient scenarios as either preferred treatment, acceptable treatment, not acceptable/contraindicated, or unsure/no opinion. Patient scenarios were declared to achieve consensus for the preferred and not acceptable/contraindicated categories when at least 80% of the survey respondents agreed on a response, and a 90% threshold was required for the acceptable treatment category, defined by an acceptable treatment or preferred treatment response. RESULTS: Seventy-two members agreed to participate and were deemed to have the requisite expertise to contribute based on their survey responses regarding clinical practice and patient volume. There were 20 clinical scenarios that reached 90% consensus as an acceptable treatment, with RSA selected for 18 scenarios and arthroscopic débridement and/or partial repair selected for 2. RSA was selected as the singular preferred treatment option in 8 scenarios. Not acceptable/contraindicated treatment options reached consensus in 8 scenarios, of which, 4 related to SCR, 3 related to RSA, and 1 related to partial repair with graft augmentation. CONCLUSION: This Delphi process exhibited significant consensus regarding RSA as a preferred treatment strategy in older patients with pseudoparesis, an irreparable subscapularis, and dynamic instability. In addition, the process identified certain unacceptable treatments for MIRCTs such as SCR in older patients with pseudoparesis and an irreparable subscapularis or RSA in young patients with an intact or reparable subscapularis without pseudoparesis or dynamic instability. The publication of these scenarios and areas of consensus may serve as a useful guide for practitioners in the management of MIRCTs.

Clinical and Imaging Outcomes After Arthroscopic Superior Capsule Reconstruction With Human Dermal Allograft for Irreparable Posterosuperior Rotator Cuff Tears: A Minimum 2-Year Follow-Up.

PURPOSE: To report the clinical and structural outcomes for non-pseudoparalytic irreparable posterosuperior rotator cuff tears treated with superior capsule reconstruction (SCR) using dermal allograft (DA). METHODS: Patients who underwent SCR using DA with a mean thickness of 3 mm for irreparable posterosuperior rotator cuff tears and underwent surgery at least 2 years earlier were included. Outcomes were assessed prospectively by the American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation, and Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) scores; patient satisfaction; and visual analog scale for pain. Structurally, acromiohumeral distances (AHDs) were assessed both preoperatively and postoperatively (standard radiographs). Graft integrity was assessed by magnetic resonance imaging. Clinical failures were reported. RESULTS: We included 22 patients with a mean age of 56 years (range, 41-65 years) and a mean follow-up period of 2.1 years (range, 2-3 years). The ASES score improved from 54.0 to 83.9 (P < .001); the Single Assessment Numeric Evaluation score improved from 44.9 to 71.4 (P < .001); and Quick Disabilities of the Arm, Shoulder and Hand score (QuickDASH) improved from 37.6 to 16.2 (P = .001). Of the patients, 85% achieved an improvement in the ASES score that exceeded the minimal clinically important difference (11.1 points). The median patient satisfaction rating was 8.5 (range, 1-10). The median preoperative visual analog scale score decreased from 4 to 0 (range, 0-3) postoperatively (P < .001). Complete radiographs of 19 of 22 patients (86%) were obtained at a mean of 5.2 months (range, 1.4-10 months) postoperatively and showed a significant increase in the mean AHD from 7.0 mm preoperatively to 8.3 mm postoperatively (P = .029). Postoperative magnetic resonance imaging scans were obtained in 95% of the patients (21 of 22) at a mean of 2.5 months (range, 0.3-10.2 months) postoperatively and showed graft integrity rates of 100% (21 of 21) on the tuberosity side, 76% (16 of 21) at the midsubstance, and 81% (17 of 21) on the glenoid side. No significant differences in clinical outcome scores (P > 0.930) were found in patients with intact grafts versus those with torn grafts. The number of previous shoulder surgical procedures was a negative predictor of clinical outcome. There was 1 clinical failure. CONCLUSIONS: SCR using DA for irreparable tears improves outcomes with high satisfaction and high graft integrity at short-term follow-up. Graft integrity, although correlated with an increased AHD, had no correlation with clinical outcomes at final follow-up. LEVEL OF EVIDENCE: Level IV, case series.

A Systematic Review and Meta-analysis of Biceps Tenodesis Fixation Strengths: Fixation Type and Location Are Biomechanically Equivalent.

PURPOSE: The purpose of this meta-analysis and systematic review was to critically evaluate the biomechanical outcomes of different fixation constructs for a variety of biceps tenodesis techniques in cadaveric models based on both type of fixation and location. METHODS: A PROSPERO-registered systematic review (CCRD42018109243) of the current literature was conducted with the terms "long head of biceps" AND "tenodesis" AND "biomechanics" and numerous variations thereof in the PubMed, Embase, and Cochrane databases, yielding 1,460 abstracts. After screening by eligibility criteria, 18 full-text articles were included. The individual biomechanical factors evaluated included ultimate load to failure (in newtons), stiffness (in newtons per millimeter), and cyclic displacement (in millimeters). After reviewing the included literature, we performed a quality analysis of the studies (Quality Appraisal for Cadaveric Studies scale score) and a meta-analysis comparing raw mean differences in data between the suprapectoral and subpectoral fixation location groups, as well as between the fixation construct groups. RESULTS: Among the 18 included studies, 347 cadaveric specimens were evaluated for ultimate load to failure, stiffness, and cyclic displacement when comparing both location (suprapectoral vs subpectoral) and tenodesis fixation type (interference screw vs cortical button, suture anchor, or all-soft-tissue techniques). Interference screw fixation showed significantly greater mean stiffness by 8.0 N/mm (P = .013) compared with the other grouped techniques but did not show significant differences when evaluated for ultimate load to failure and cyclic displacement (P = .28 and P = .18, respectively). Additionally, no difference in construct strength was seen when comparing the fixation strength of suprapectoral versus subpectoral techniques for stiffness, ultimate load to failure, and cyclic loading (P = .47, P = .053, and P = .13, respectively). CONCLUSIONS: In this meta-analysis, no significant biomechanical differences were found when the results were stratified by specific surgical technique (interference screw vs other tenodesis techniques) and location (suprapectoral vs subpectoral biceps tenodesis). CLINICAL RELEVANCE: As a result of this study, when biomechanically evaluating specific tenodesis constructs, the individual clinician has the liberty of choosing the fixation technique based on his or her preference and knowledge of shortcomings of each type of fixation construct.

Medial Patellotibial Ligament Reconstruction Improves Patella Tracking When Combined With Medial Patellofemoral Reconstruction: An In Vitro Kinematic Study.

PURPOSE: To investigate the isolated and combined effects of medial patellofemoral ligament (MPFL) and medial patellotibial ligament (MPTL) deficiency and reconstruction on patellofemoral kinematics. METHODS: Sixteen matched-paired female cadaveric knee specimens with a mean age of 53.5 years (range, 26-65) were tested in 5 conditions: (1) intact, (2) MPFL or MPTL cut, (3) MPFL and MPTL combined cut, (4) MPFL or MPTL reconstruction, and (5) MPFL and MPTL combined reconstruction. Dynamic testing allowed continuous analysis of kinematics from 0° to 90° of knee flexion. Knees were also tested statically using a lateral load of 45 N at 0°, 30°, 60°, and 90° of flexion. In both dynamic and static loading tests, a motion capture system detected patellar position for each testing state to distinguish changes in patellar kinematics. Random-intercepts linear mixed-effects models were used to compare patellar kinematics. RESULTS: The MPFL is the primary restraint to lateral translation of the patella at all knee flexion angles. MPTL deficiency alone did not create significant patella instability, but further increased instability when the MPFL was deficient. Isolated MPFL and combined reconstruction provided improved stability. Through full range of motion native patella tracking was best recreated with combined ligament reconstruction. CONCLUSIONS: The MPFL plays the greatest role in medial patellar stability, but the MPTL appears to have an influence on patella tracking. This study provides further understanding to the impact of the MPFL and MPTL on patellofemoral motion with implications for reconstruction to improve stability and optimize patellofemoral tracking. CLINICAL RELEVANCE: This study provides further understanding of the role of the MPFL and MPTL on patellofemoral motion with implications for reconstruction to improve stability and optimize patellofemoral tracking.

Biomechanical Evaluation of Knotless and Knotted All-Suture Anchor Repair Constructs in 4 Bankart Repair Configurations.

PURPOSE: To evaluate the biomechanical performance of Bankart repair using 1.8-mm knotless all-suture anchors in comparison to 1.8-mm knotted all-suture anchors with both simple and horizontal mattress stitch configurations. METHODS: Thirty fresh-frozen human cadaveric shoulders were dissected to the capsule, leaving the glenoid and humeral capsular insertions intact. A standardized anteroinferior labral tear was created and repaired using 3 anchors. A 2 × 2 factorial design was implemented, with 6 matched pairs randomized between knotless and knotted anchor repairs and 6 matched pairs randomized into simple and horizontal mattress stitch configurations. In addition, 6 unpaired shoulders were used to evaluate the native capsulolabral state. First failure load, ultimate load, and stiffness were assessed. Linear mixed-effects modeling was used to compare endpoints. Digital image correlation was used to evaluate capsular strain throughout testing. Failure modes were reported qualitatively. RESULTS: The knotless all-suture anchor repair showed similar biomechanical strength to the knotted all-suture anchors for first failure load (coefficient, 142 N; 95% confidence interval [CI], -30 to 314 N; P = .12), ultimate load (coefficient, 11.1 N; 95% CI, -104.9 to 127.2 N; P = .847), and stiffness (coefficient, 3.4 N/mm2; 95% CI, -14.1 to 20.9 N/mm2; P = .697) when stitch configuration was held constant. No statistically significant differences were found on comparison of simple and mattress stitch configurations for first failure load (coefficient, -31 N; 95% CI, -205 to 143 N; P = .720), ultimate load (coefficient, 112 N; 95% CI, -321 to 97 N; P = .291), and stiffness (coefficient, -9.6 N/mm2; 95% CI, -27.3 to 8.1 N/mm2; P = .284) when anchor type was held constant. Specimens with knotless anchors and simple stitch techniques resulted in lower stiffness compared with the native state (P = .030). The knotless-mattress configuration resulted in significantly lower strain than the knotted-mattress (P = .037) and knotless-simple (P = .019) configurations and was the only configuration that did not result in a significant increase in strain compared with the intact specimens (P = .216). Fewer instances of suture slippage (loss of loop security) were observed with knotless anchors versus knotted anchors (11% vs 30%), and less soft-tissue failure was observed with the mattress stitch configuration versus the simple stitch configuration (36% vs 47%). CONCLUSIONS: Knotless and knotted all-suture anchor repairs with simple and mattress stitch configurations showed similar values of ultimate load, first failure load, and stiffness. However, the horizontal mattress stitch configuration proved to decrease capsular strain more similarly to the native state compared with the simple stitch configuration. Ultimate load and first failure load for all repairs were similar to those of the native state. CLINICAL RELEVANCE: Knotless all-suture anchors have a smaller diameter than solid anchors, can be inserted through curved guides, and preserve glenoid bone stock. This study presents knotless, tensionable all-suture anchor repair for labral tears that displays high biomechanical fixation strength, similar to the native capsulolabral state.

Minimum 2-year clinical outcomes after superior capsule reconstruction compared with reverse total shoulder arthroplasty for the treatment of irreparable posterosuperior rotator cuff tears in patients younger than 70 years.

BACKGROUND: To compare clinical outcomes following arthroscopic superior capsule reconstruction (SCR) using a dermal allograft (DA) with reverse total shoulder arthroplasty (RTSA) when used to treat irreparable posterosuperior rotator cuff tears without glenohumeral osteoarthritis (GHOA) in patients younger than 70 years. METHODS: In this case-control study, patients who underwent SCR or RTSA for the treatment of irreparable posterosuperior rotator cuff tears, who were younger than 70 years at the time of surgery, and who were at least 2 years out of surgery were included. Clinical outcomes were assessed using the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), Single Assessment Numerical Evaluation (SANE), Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) scores and the 12-Item Short Form Health Survey (SF-12). Return to sports and patient satisfaction along with clinical failures (recurrent pain or persistent pain or loss of function), revisions, and complications were reported. RESULTS: Two-year follow-up was obtained on 22/22 patients (100%) in the SCR group and 29/33 patients (88%) in the RTSA group. Group differences were significant for age (SCR mean, 57 ± 6.6 years, vs. RTSA mean, 63 ± 4.9 years; P < .001) and follow-up interval (SCR mean, 2.1 years, vs. RTSA mean, 2.9 years; P = .001). Preoperative outcome scores showed no significant differences (all P > .05) between groups. No significant differences in postoperative outcome scores were detected (P > .05) between SCR and RTSA: the mean ASES score was 82.6 ± 15.5 vs. 79.3 ± 21.4, mean SANE score was 71.4 ± 24.5 vs. 75.4 ± 23.3, mean QuickDASH score was 16.2 ± 16.9 vs. 25.3 ± 21.0, and mean SF-12 was 47.7 ± 8.8 vs. 46.9 ± 10.4. No significant differences in return-to-sport responses were noticed between groups at baseline or postoperatively (P = .585, P = .758). One SCR was revised at 1.2 years with revision SCR and 1 RTSA had the glenoid component revised day 1 postoperatively for instability. Both patient groups achieved successful clinical outcomes. CONCLUSION: SCR using DA results in similar postoperative functional outcomes in a younger patient population when compared to RTSA for the treatment of irreparable posterosuperior rotator cuff tears, without GHOA, at short-term follow-up.

Complications and implant survivorship following primary reverse total shoulder arthroplasty in patients younger than 65 years: a systematic review.

BACKGROUND: Concerns exist regarding the complication rates and implant survivorship of reverse total shoulder arthroplasty (RTSA) in younger patients. METHODS: A systematic review of the literature regarding the existing evidence on RTSA in patients younger than 65 years was performed using the CENTRAL (Cochrane Central Register of Controlled Trials), PubMed, and Embase databases on June 9, 2019. Articles published between 1995 and 2019 with combinations of the following keywords were identified: "reverse shoulder arthroplasty" and "65," "60," and/or "55." Complications, reoperations, and revisions were recorded. Reoperation-free survival and implant survival rates were grouped at 2, 5, and 10 years. Range of motion and clinical outcomes, along with postoperative radiographic results, were recorded. RESULTS: Data from 7 studies with a total of 286 shoulders were obtained for quantitative analysis. The mean patient age was 58.4 years (mean age range, 48.9-60.4 years), and the mean follow-up period was 4.7 years (mean follow-up range, 3.0-7.8 years). The overall rate of complications was 18.6%; reoperations, 14.4%; and revisions, 11.2%. The reoperation-free survival rate was 97% at 2 years, 88%-90% at 5 years, and 76% at 10 years. The implant survival rate was 99% at 2 years, 91%-98% at 5 years, and 88% at 10 years. Active abduction, forward elevation, and external rotation significantly improved from preoperatively to postoperatively. All clinical outcome measures significantly improved from preoperatively to postoperatively, with no decline seen over time. The overall rate of infrascapular notching was 22.7% at final follow-up. CONCLUSION: RTSA is safe and effective in patients younger than 65 years. Complication, reoperation, and revision rates were similar to those seen in older patient cohorts, without an increase in revisions owing to aseptic loosening. Clinical outcome scores showed significant and lasting improvements.

Influence of Medial Meniscus Bucket-Handle Repair in Setting of Anterior Cruciate Ligament Reconstruction on Tibiofemoral Contact Mechanics: A Biomechanical Study.

PURPOSE: To compare the impact of an inside-out repair versus meniscectomy of a medial meniscus bucket-handle tear in restoring native contact areas and pressures across the tibial plateaus in the setting of an anterior cruciate ligament (ACL) reconstruction (ACLR). METHODS: Ten fresh-frozen cadaveric knees were tested in 6 knee conditions (1: intact; 2: ACL torn and bucket-handle tear of medial meniscus, flipped; 3: bucket-handle tear of medial meniscus, reduced; 4: bucket-handle tear of medial meniscus, repaired via inside-out vertical mattress suture technique; 5: ACLR with bone patella tendon bone autograft and bucket-handle repair; 6: ACLR and medial meniscus bucket-handle tear debridement) at 4 flexion angles (0°, 30°, 45°, and 60°), under a 1,000-N axial load. Contact area and pressure were measured with Tekscan sensors. RESULTS: ACLR with a concurrent medial meniscectomy for a medial meniscus bucket-handle tear resulted in significantly decreased contact area (P < .05) and increased mean and peak pressure in both the medial and lateral compartments across all tested flexion angles (P < .05). The ACLR with medial meniscectomy state also demonstrated significantly lower contact area than the bucket-handle repair state between 30° and 60° of flexion (all P < .05). CONCLUSIONS: Resection of a bucket-handle medial meniscus tear concurrent with an ACLR resulted in significant increases in mean and peak contact pressures in not only the medial but also the lateral compartment. Preservation of the medial meniscus in the face of a bucket-handle tear is essential to more closely restore native tibiofemoral biomechanics. CLINICAL RELEVANCE: The increased mean and peak tibiofemoral contact pressure seen with excision of a bucket-handle medial meniscus tear would over time result in increased cartilaginous degradation and resultant osteoarthritis. Decreasing both of these factors through concomitant ACLR and inside-out bucket-handle meniscal repairs should improve patient outcomes by restoring knee biomechanics and kinematics closer to that of the native state.

Predicting Severe Cartilage Damage in the Hip: A Model Using Patient-Specific Data From 2,396 Hip Arthroscopies.

PURPOSE: To determine patient-specific factors that can be used to predict the presence of severe articular cartilage damage in the hip in patients without osteoarthritis. METHODS: The prevalence of severe (Outerbridge grade III or IV) cartilage damage to the acetabulum and femoral head was prospectively recorded at hip arthroscopy. Patients who underwent primary hip arthroscopic surgery between 2006 and 2016 performed by a single surgeon were included. Patients were excluded if they underwent previous hip surgery, had poor-quality radiographs, were younger than 16 years at the time of surgery, or had a minimal joint space of 2 mm or less. The relation between severe cartilage damage and preoperative patient characteristics was examined using multivariable logistic regression analysis with restricted cubic splines. RESULTS: Of the 2,396 hips presenting for hip arthroscopy, 995 (41%) had severe cartilage damage to the acetabulum and 257 (11%) had severe cartilage damage to the femoral head. Older age was a significant risk factor for severe cartilage damage both to the acetabulum (χ2 = 69.5, P < .001) and to the femoral head (χ2 = 53.9, P < .001). An age of 45 years was associated with a 1.96 (95% confidence interval, 1.54-2.49) increase in the odds of severe acetabular cartilage damage and a 3.94 (95% confidence interval, 2.61-5.94) increase in the odds of severe femoral head cartilage damage relative to an age of 20 years. Male sex was associated with severe cartilage damage to the acetabulum (χ2 = 66.7, P < .001), and a lower center-edge angle was a significant risk factor for severe cartilage damage to the femoral head (χ2 = 78.5, P < .001). Predictive nomograms were established for severe cartilage lesions. CONCLUSIONS: The primary risk factors for severe hip cartilage damage were older age for both the femoral head and acetabulum; a lower center-edge angle and larger Tönnis angle for the femoral head; and male sex, body mass index, alpha angle, and joint space for the acetabulum. The likelihood of cartilage damage to the hip can be estimated clinically using a prediction nomogram. LEVEL OF EVIDENCE: Level III, cross-sectional study.

The Influence of Naproxen on Biological Factors in Leukocyte-Rich Platelet-Rich Plasma: A Prospective Comparative Study.

PURPOSE: To quantify and compare normative catabolic and anabolic factor concentrations in leukocyte-rich platelet-rich plasma (LR-PRP) at various time points, including baseline, 1 week after initiating naproxen use, and after a 1-week washout period. METHODS: Asymptomatic healthy donors aged between 18 and 70 years were recruited (average age, 36.6 years; range, 25-64 years). Subjects were excluded from the study if they were actively taking any prescribed medications or nonsteroidal anti-inflammatory drugs (NSAIDs) or if they had any of the following at present or previously: blood or immunosuppression disorders, cancer, osteonecrosis, rheumatoid arthritis, avascular necrosis, NSAID intolerance, gastrointestinal or peptic ulcer disease, or kidney dysfunction. The anabolic factors vascular endothelial growth factor, fibroblast growth factor 2, platelet-derived growth factor AB (PDGF-AB), and platelet-derived growth factor AA (PDGF-AA) and the catabolic factors interleukin (IL) 1ß, IL-6, IL-8, and tumor necrosis factor α in LR-PRP were measured. Peripheral blood was drawn at 3 time points: baseline, after 1 week of naproxen use, and after a 1-week washout period. RESULTS: The angiogenic factors PDGF-AA (44% decrease in median) and PDGF-AB (47% decrease) significantly declined from baseline (P < .05) after 1 week of naproxen use. There was a significant recovery (P < .05) of PDGF-AA (94% increase) and PDGF-AB (153% increase) levels after the 1-week washout period, with a return to baseline levels. The catabolic factor IL-6 also had a significant decline from baseline (77% decrease in median, P < .05) after 1 week of naproxen use. After a 1-week washout period, the IL-6 level was similar to the baseline level (130% increase, P < .05). CONCLUSIONS: Naproxen use diminished several biological factors in LR-PRP; however, a 1-week washout period was sufficient for the recovery of PDGF-AA, PDGF-AB, and IL-6 to return to baseline levels. Tumor necrosis factor α, IL-1ß, IL-8, vascular endothelial growth factor, and fibroblast growth factor 2 did not show differences between the 3 time points of data collection. Discontinuing NSAIDs for a minimum of 1 week before LR-PRP treatment may improve certain biological factor levels. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Defining the three most responsive and specific CT measurements of ankle syndesmotic malreduction.

PURPOSE: The purpose of this study was to compare the reliability and accuracy of existing computed tomography (CT) methods for measuring the distal tibiofibular syndesmosis in uninjured, paired cadaveric specimens and in simulated malreduction models. It was hypothesized that a repeatable set of measurements exists to accurately and quantitatively describe the typical forms of syndesmotic malreduction using contralateral ankle comparison. METHODS: Twelve cadaveric lower-leg specimen pairs were imaged with CT to generate models for this study. Thirty-five measurements were performed on each native model. Next, four distinct fibular malreductions were produced via digital simulation and all measurements were repeated for each state: (1) 2-mm lateral translation; (2) 2-mm posterior translation; (3) 7-degree external rotation; (4) the previous three states combined. The modified standardized response mean (mSRM) was calculated for each measurement. To assess rater reliability and side-to-side agreements of the native state measurements, intraclass correlation coefficients (ICC) and Pearson correlation coefficients (PCC) were calculated, respectively. RESULTS: The most responsive measurements for detecting isolated malreduction were the Leporjärvi clear space for lateral translation, the Nault anterior tibiofibular distance for posterior translation, and the Nault talar dome angle for external rotation of the fibula. These measurements demonstrated fair to excellent inter-rater ICCs (0.64-0.76) and variable side-to-side PCCs (0.14-0.47). CONCLUSIONS: The most reliable method to assess the syndesmosis on CT was to compare side-to-side differences using three distinct measurements, one for each type of fibular malreduction, allowing assessment of the magnitude and directionality of syndesmosis malreduction. Reliable evaluation is essential for assessing subtle syndesmosis injuries, malreduction and surgical planning.