Endoscopic Tendon Compression Bridge Technique for Repair of Partial-Thickness Gluteus Medius Tears With Concomitant Arthroscopy for Labral Tears: Minimum 2-Year Outcomes With Benchmark Control Group.

BACKGROUND: The transtendinous technique has been used to treat partial-thickness gluteus medius tears in the setting of concomitant arthroscopy for labral tears. The tendon compression bridge technique for gluteus medius repair has been developed as an alternative method, providing several advantages; however, comparative studies between the 2 techniques are lacking in the literature. PURPOSE: (1) To evaluate the short-term patient-reported outcomes (PROs) of the tendon compression bridge technique and (2) to compare these findings with short-term PROs of the transtendinous technique. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data were prospectively collected on patients who were followed for a minimum of 2 years after an endoscopic tendon compression bridge procedure for gluteus medius repair in the setting of concomitant hip arthroscopy for labral tears. The following PROs were collected preoperatively and postoperatively: modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score-Sports Specific Subscale, visual analog scale score for pain, and the International Hip Outcome Tool. Clinical outcomes were assessed using the Patient Acceptable Symptom State, minimal clinically important difference, and maximum outcome improvement satisfaction threshold. Patients were propensity matched 1:1 to a cohort that underwent gluteus medius repair using the endoscopic transtendinous technique with concomitant hip arthroscopy. RESULTS: A total of 48 hips (48 patients) that met inclusion criteria (age, 53.3 ± 9.8 years; 92% female; body mass index, 26.7 ± 4.6), with a mean follow-up of 38.5 ± 15.7 months, were matched to 48 hips (46 patients) that underwent gluteus medius repair using the transtendinous technique. Both groups demonstrated significant improvement from preoperative scores to latest follow-up (P < .05). Mean magnitude of improvement and latest follow-up scores were not significantly different between the tendon compression bridge group and the transtendinous group, and the groups demonstrated similar favorable rates of achieving Minimal Clinically Important Difference (79% vs 79%, respectively), Patient Acceptable Symptom State (73% vs 73%, respectively), and Maximum Outcome Improvement Satisfaction threshold (65% vs 58%, respectively) for modified Harris Hip Score (P > .05). Patient satisfaction between groups was similar (8.1 ± 2.2 vs 7.7 ± 2.7, respectively) (P = .475). CONCLUSION: At minimum 2-year follow-up, the endoscopic tendon compression bridge technique for partial-thickness gluteus medius tears, when performed with concomitant hip arthroscopy, was associated with significant improvement in functional outcomes. These postoperative results were comparable with those of a matched cohort that underwent the endoscopic transtendinous technique for partial-thickness gluteus medius tears, suggesting that the tendon compression bridge technique for gluteus medius repair is an effective treatment option for partial-thickness gluteus medius tears.

Utility of 3D Planning Software in Understanding Residual Proximal Femoral Deformity for Planning of Revision Hip Arthroscopy.

BACKGROUND: During the early evolution of femoroacetabular impingement (FAI) treatment, undercorrection of femoral deformity was a leading cause of hip arthroscopy failures. As the pendulum has swung, overresection of femoral deformity has increased in prevalence as a cause of persistent hip pain after arthroscopy. Computed tomography (CT) scans are increasingly being used in hip arthroscopy for preoperative planning purposes and may allow for improved 3-dimensional (3D) assessment of complex femoral deformities after previous femoroplasty. PURPOSE: To assess whether CT scans provide additional utility over standard radiographs in understanding proximal femoral morphology in patients being evaluated for revision hip arthroscopy after previous femoroplasty in the setting of FAI. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 3. METHODS: Preoperative CT scans and standard radiographs were obtained in 80 patients who underwent revision hip arthroscopy for FAI. The anteroposterior and Dunn radiographic views were used to assess patients for residual proximal femoral deformity and were compared with the CT scan views using a commercially available software program. Determinations of underresection were made using alpha angle, while overresection was determined according to a previously described technique. Chi-square tests were performed to determine statistical significance between radiographic and CT classifications of overresection, underresection, and concomitant over- and underresection. A kappa value was calculated to determine the agreement between measurements on the radiographs and CT scans. RESULTS: There were 30 patients (37.5%) for whom the CT scans revealed information about femoral morphology that was not detected on the radiographs. The kappa value of agreement was 0.28 between CT and radiographic measurements. Underresected cams were detected in 30 patients (37.5%) on CT scans versus 17 patients (21.3%) on radiographs (P = .024). Overresected cams were detected in 31 patients (38.8%) on CT scans versus 14 patients (17.5%) on radiographs (P = .0049). Concomitant areas of under- and overresection were detected in 12 patients (15.0%) on CT scans versus 3 patients (3.8%) on radiographs (P = .027). CONCLUSION: CT scans with 3D planning software may be more sensitive than traditional radiographic views at detecting aberrant proximal femoral anatomy in the setting of failed FAI surgery. The use of 3D planning software may be considered as an adjunctive tool to better understand complex deformity in the proximal femur for the planning of revision hip arthroscopy.

Fixation of the Proximal Hamstring Tendon Using an All-Suture Tensionable Knotless Technique.

Proximal hamstring injuries are a common sports and recreational injury among the active patient population. Surgical fixation of the tendons of the hamstring muscle complex, as opposed to conservative treatment alone, has shown improved patient outcomes, prompting the evolution of the suture anchors utilized in these repairs. Previous studies investigating the biomechanical properties of hamstring repair anchors have focused on double-row knotless techniques, in which the fixation of the overall construct relies on each individual anchor to maintain fixation. While these constructs have demonstrated biomechanical strength and clinical durability, each suture anchor represents a potential point of failure for the entire construct due to the crossed stitch anchor configuration. To address this limitation, recent tensionable knotless all-suture anchor designs have been implemented with success due to their smaller size and biomechanical strength. The aim of this technical note is, thus, to describe a technique for proximal hamstring repair using a tensionable knotless all-suture anchor construct that has 5 independent mattress sutures and, in doing so, employs the biomechanical strength of knotless fixation but eliminates the potential single point of failure seen with current knotless suture anchor designs.

Hip Arthroscopy Trends: Increasing Patient Out-of-Pocket Costs, Lower Surgeon Reimbursement, and Cost Reduction With Utilization of Ambulatory Surgery Centers.

PURPOSE: To (1) report on trends in immediate procedure reimbursement, patient out-of-pocket expenditures, and surgeon reimbursement in hip arthroscopy (2) compare trends in ambulatory surgery centers (ASC) versus outpatient hospitals (OH) utilization; (3) quantify the cost differences (if any) associated with ASC versus OH settings; and 4) determine the factors that predict ASC utilization for hip arthroscopy. METHODS: The cohort for this descriptive epidemiology study was any patient over 18 years identified in the IBM MarketScan Commercial Claims Encounter database who underwent an outpatient hip arthroscopy, identified by Current Procedural Terminology codes, in the United States from 2013 to 2017. Immediate procedure reimbursement, patient out-of-pocket expenditure, and surgeon reimbursement were calculated, and a multivariable model was used to determine the influence of specific factors on these outcome variables. Statistically significant P values were less than .05, and significant standardized differences were more than 0.1. RESULTS: The cohort included 20,335 patients. An increasing trend in ASC utilization was observed (P = .001), and ASC utilization for hip arthroscopy was 32.4% in 2017. Patient out-of-pocket expenditures for femoroacetabular impingement surgery increased 24.3% over the study period (P = .003), which was higher than the rate for immediate procedure reimbursement (4.2%; P = .007). ASCs were associated with $3,310 (28.8%; P = .001) reduction in immediate procedure reimbursement and $47 (6.2%; P = .001) reduction in patient out-of-pocket expenditure per hip arthroscopy. CONCLUSIONS: ASCs provide a significant cost difference for hip arthroscopy. Although there is an increasing trend toward ASC utilization, it remains relatively low at 32.4% in 2017. Thus, there are opportunities for expanded ASC utilization, which is associated with significant immediate procedure reimbursement difference of $3,310 and patient out-of-pocket expenditure difference of $47 per hip arthroscopy case, ultimately benefiting healthcare systems, surgeons, and patients alike. LEVEL OF EVIDENCE: Level III, retrospective comparative trial.

Return to Sport After Arthroscopic Capsular Repair in Elite Baseball Players.

Background: Chronic attritional midsubstance capsular tears arising from repetitive throwing stress are a rare but important source of pain and dysfunction in elite baseball players; however, little is known regarding outcomes after arthroscopic capsular repair. Purpose: To evaluate the patient-reported outcomes and return-to-sport (RTS) rates after arthroscopic capsular repair in elite baseball players. Study Design: Case series; Level of evidence, 4. Methods: We identified 11 elite-level baseball players who were treated with arthroscopic repair for a midsubstance glenohumeral capsular tear by a single surgeon with a uniform approach and a standardized postoperative protocol between 2012 and 2019. All players had at least 2 years of follow-up data. Demographic data and concomitant surgical procedures were recorded. Preoperative and postoperative Kerlan-Jobe Orthopaedic Clinic (KJOC) scores and Single Assessment Numeric Evaluation (SANE) scores were collected in a subset of the cohort, and statistical comparisons were made. A telephone survey was conducted to determine the patients' RTS level and outcome scores. Statistical comparisons between preoperative and postoperative outcomes scores were made using t tests. Results: Eight major league players, 1 minor league player, and 2 collegiate players were included. There were 9 pitchers, 1 catcher, and 1 outfielder. All patients had debridement of the posterosuperior labrum and rotator cuff. Two pitchers underwent a rotator cuff repair, and 1 outfielder underwent a posterior labral repair. The mean age at the time of surgery was 26.9 years (range, 20-34 years), with a mean follow-up of 3.5 years (range, 2.6-5.9 years). There were significant preoperative versus postoperative improvements in the mean KJOC (20.6 vs 89.8; P = .0002) and SANE (28.3 vs 86.7; P = .001) scores. All patients reported a high degree of satisfaction. At a mean of 16.3 months (range, 6.5-25.4 months), 10 of 11 (90.1%) players met the Conway-Jobe good or excellent criteria for RTS. Conclusion: Arthroscopic capsular repair provided significant improvements in functional outcomes in elite baseball players, high levels of patient satisfaction, and high levels of RTS.

Ambulatory Surgery Centers Significantly Decrease Total Health Care Expenditures in Primary Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Anterior cruciate ligament reconstruction (ACLR) is a commonly performed orthopaedic procedure. The volume and cost of ACLR procedures are increasing annually, but the drivers of these cost increases are not well described. PURPOSE: To analyze the modifiable drivers of total health care utilization (THU), immediate procedure reimbursement, and surgeon reimbursement for patients undergoing ACLR using a large national commercial insurance database from 2013 to 2017. STUDY DESIGN: Descriptive epidemiology study. METHODS: For this study, the cohort consisted of patients identified in the MarketScan Commercial Claims and Encounters database who underwent outpatient arthroscopic ACLR in the United States from 2013 to 2017. Patients with Current Procedural Terminology code 29888 were included. THU was defined as the sum of any payment related to the ACLR procedure from 90 days preoperatively to 180 days postoperatively. A multivariable model was utilized to describe the patient- and procedure-related drivers of THU, immediate procedure reimbursement, and surgeon reimbursement. RESULTS: There were 34,862 patients identified. On multivariable analysis, the main driver of THU and immediate procedure reimbursement was an outpatient hospital as the surgical setting (US$6789 increase in THU). The main driver of surgeon reimbursement was an out-of-network surgeon (US$1337 increase). Health maintenance organization as the insurance plan type decreased THU, immediate procedure reimbursement, and surgeon reimbursement (US$955, US$108, and US$38 decrease, respectively, compared with preferred provider organization; P < .05 for all). CONCLUSION: Performing procedures in more cost-efficient ambulatory surgery centers had the largest effect on decreasing health care expenditures for ACLR. Health maintenance organizations aided in cost-optimization efforts as well, but had a minor effect on surgeon reimbursement. Overall, this study increases transparency into what drives reimbursement and serves as a foundation for how to decrease health care expenditures related to ACLR.

Patient-Reported Outcomes Improve at 2-Year Minimum Follow-Up After Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Systematic Review.

PURPOSE: To provide an updated review of recent literature on postoperative outcomes following hip arthroscopy for femoroacetabular impingement syndrome (FAIS), focusing on larger-population studies with a minimum 2-year follow-up published within the last 5 years. METHODS: A literature search of the PubMed, Ovid Medline, Web of Science, and Cochrane databases was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles were screened for clinical studies published from 2017 to 2022 with greater than 100 patients and minimum 2-year follow-up. Exclusion criteria included failure to report postoperative patient-reported outcomes (PROs), no preoperative radiographic measurements, and surgery for pathology other than FAIS. Data collection included study characteristics, patient demographics, radiographic findings, intraoperative findings, procedures performed, postoperative PROs, and subsequent surgeries. RESULTS: Nine studies met inclusion criteria. Mean or median patient ages ranged from 32.3 to 41 years, with 4 studies reporting on greater than 50% female patients. Mean preoperative lateral center edge angles and alpha angles ranged from 30.2° to 37° and from 56.2° to 71°, respectively. Labral repairs (range 69.7%-100%) were performed more commonly than debridements (range 0%-26.3%). All studies demonstrated improved PROs at most recent follow-up. Seven studies reported mean or median modified Harris Hip Scores, with preoperative and postoperative values that ranged from 53.1 to 80 and from 67.4 to 100, respectively. Revision hip arthroscopies and conversions to hip arthroplasty ranged from 0.8% to 11.6% and from 0% to 34%, respectively. CONCLUSIONS: All included studies found improvements in PROs after hip arthroscopy for FAIS at a minimum of 2-year follow-up. Conversion to total hip arthroplasty is most common in older patients at minimum 10-year follow-up. LEVEL OF EVIDENCE: Level IV, systematic review of Level I through IV studies.

Hip Capsular Repair Results in Improved Patient-Reported Outcomes and Survivorship: A Systematic Review of the Literature.

PURPOSE: To determine whether routine capsular closure following hip arthroscopy for femoroacetabular impingement (FAI) in patients without dysplasia results in improved patient-reported outcomes (PROs) and increased survivorship rates. METHODS: A literature search of the PubMed, Embase, and Cochrane Library databases was performed using the Preferred Reporting for Systematic Reviews and Meta-Analyses guidelines for clinical studies reporting PROs following arthroscopic hip labral repair for FAI. A quality assessment was performed using the Methodological Index for Non-randomized Studies grading system. Inclusion criteria consisted of comparative clinical studies investigating routine capsular closure with nonclosure in patients undergoing hip arthroscopy for the treatment of FAI and labral tears. Exclusion criteria included non-English language, minimum follow-up of less than 2 years after surgery, technique articles, case reports, noncomparative case series of fewer than 10 patients, failure to report surgical technique, absence of postoperative PROs, or partial repair. Data collection included study characteristics, demographics, indications, radiographic metrics, perioperative findings, surgical technique, baseline and most recent PROs, and subsequent surgeries. RESULTS: A total of 531 articles were reviewed, of which 3 were included with 249 hips that underwent capsular repair and 157 hips that underwent capsulotomy with no repair. There were 2 Level III studies and 1 Level II study, with an average The Methodological Index for Non-randomized Studies score of 16.7. All studies cited FAI and labral tear as an indication for surgery. All studies demonstrated improved PROs from baseline to most recent follow-up. Postoperatively, the repair group reported modified Harris Hip Score values ranging from 80.8 to 87, whereas the nonrepair group reported scores ranging from 76 to 81.7. In addition, the repair group reported postoperative Hip Outcome Score - Sports-Specific Subscale values ranging from 68.1 to 9, whereas the nonrepair group reported scores ranging from 65.3 to 76.1. The studies also reported minimal clinically important difference for modified Harris Hip Score, with the repair group reporting percentages ranging from 71 to 100 and the nonrepair group reporting percentages ranging from 52 to 95.6. All 3 studies also observed a lower rate of hip survivorship in the nonrepair group, ranging from 94.6 to 100 in the repair group and 90.8 to 100 in the nonrepair group. There were no significant differences in the rate of revision arthroscopy between groups. CONCLUSIONS: Patients without dysplasia who undergo capsular repair have greater improvements in PROs and greater survivorship rates at early- and mid-term follow-up than patients who do not undergo capsular repair. LEVEL OF EVIDENCE: III, systematic review of level II and III studies.

Understanding Batter's Shoulder: Diagnosis, Treatment, and Outcomes.

PURPOSE OF REVIEW: Though most of the attention in recent literature on baseball injuries has been paid to throwers, one often overlooked aspect of the game is the effect of the batter's swing on the shoulder. It is well known that the batter's lead shoulder can experience significant translational forces during the player's swing, and that these are increased following a missed swing. The purpose of this paper is to review the background and pathophysiology as well as clinical presentation and treatment of players with Batter's shoulder. RECENT FINDINGS: Recent studies demonstrate that while nonoperative treatment of Batter's shoulder is still a viable first line of treatment, favorable outcomes have been reported with arthroscopic posterior labral repair for high level athletes. Batter's injury can cause significant pain and dysfunction in baseball hitters, especially during the follow through phase of swing. While conservative care can be attempted early, outcomes following arthroscopic posterior labral repair are favorable with a high rate of return to play.

Trends in Health Care Expenditures and Patient Out-of-Pocket Expenses in Primary Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Anterior cruciate ligament reconstruction (ACLR) is one of the most commonly performed orthopaedic procedures in the United States, and the number of procedures is increasing annually, as is the cost. Patients are expected to shoulder a larger out-of-pocket expenditure. PURPOSE: To answer the following questions: (1) How is reimbursement changing for ACLR, and how is this affecting patients' out-of-pocket expenditures? (2) How are reimbursements from payers and patients' out-of-pocket expenses for ACLR distributed, and how is this changing? (3) Does performing ACLR in an ambulatory surgery center (ASC) result in lower costs for payers and patients? STUDY DESIGN: Economic and decision analysis study; Level of evidence, 4. METHODS: A total of 37,763 patients who underwent outpatient primary arthroscopic ACLR in the United States between 2013 and 2017 were identified using the IBM MarketScan Commercial Claims and Encounters Database. Patients with concomitant procedures and revision ACLR were excluded. Recorded outcomes were total patient payments and reimbursed claim totals in US dollars. RESULTS: Day-of-surgery reimbursement decreased 4.3% from $11,536 in 2013 to $11,044 in 2017, while patient out-of-pocket expenses increased 36% from $1085 in 2013 to $1480 in 2017. Day-of-surgery charges were the highest expense for patients, followed by physical therapy and magnetic resonance imaging (MRI) costs. Total reimbursement for MRI decreased 22.5%, while patient out-of-pocket expenses for MRI increased 166%. ACLR performed in an outpatient hospital resulted in 61% greater day-of-surgery expenditure for payers compared with ACLR performed in an ASC; however, the median total patient out-of-pocket savings for ACLRs performed in an ASC versus outpatient hospital was only $11. CONCLUSION: Out-of-pocket expenses for patients are increasing as they are forced to cover a larger percentage of their health care costs despite overall payer reimbursement decreasing. High-deductible health plans reimbursed the least out of all insurance types while having the highest patient out-of-pocket expenditure.

Tendon progenitor cells as biological augmentation improve functional gait and reduce scar formation after rotator cuff repair.

BACKGROUND: High rates of structural failure are reported after rotator cuff repairs due to inability to recreate the native enthesis during healing. The development of biological augmentation methods that mitigate scar formation and regenerate the enthesis is still an unmet need. Since neonatal enthesis is capable of regeneration after injury, this study tested whether delivery of neonatal tendon progenitor cells (TPCs) into the adult injured environment can enhance functional and structural supraspinatus enthesis and tendon healing. METHODS: TPCs were isolated from Ai14 Rosa26-TdTomato mouse Achilles tendons and labeled using adenovirus-Cre. Fifty-two CB57BL/6J mice underwent detachment and acute repair of the supraspinatus tendon and received either a fibrin-only or TPC-fibrin gel. Immunofluorescence analysis was carried out to determine cellularity (DAPI), fibrocartilage (SOX9), macrophages (F4/80), myofibroblasts (α-smooth muscle actin), and scar (laminin). Assays for function (gait and biomechanical testing) and structure (micro-computed tomography imaging, picrosirius red/Alcian Blue staining, type I and III collagen staining) were carried out. RESULTS: Analysis of TdTomato cells after injury showed minimal retention of TPCs by day 7 and day 14, with detected cells localized near the bursa and deltoid rather than the enthesis/tendon. However, TPC delivery led to significantly increased %Sox9+ cells in the enthesis at day 7 after injury and decreased laminin intensity across almost all time points compared to fibrin-only treatment. Similarly, TPC-treated mice showed gait recovery by day 14 (paw area and stride length) and day 28 (stance time), while fibrin-treated mice failed to recover gait parameters. Despite improved gait, biomechanical testing showed no differences between groups. Structural analysis by micro-computed tomography suggests that TPC application improves cortical thickness after surgery compared to fibrin. Superior collagen alignment at the neo-enthesis was also observed in the TPC-augmented group at day 28, but no difference was detected in type I and III collagen intensity. CONCLUSION: We found that neonatal TPCs improved and restored functional gait by reducing overall scar formation, improving enthesis collagen alignment, and altering bony composition response after supraspinatus tendon repair. TPCs did not appear to integrate into the healing tissue, suggesting improved healing may be due to paracrine effects at early stages. Future work will determine the factors secreted by TPCs to develop translational targets.

Reverse shoulder arthroplasty for rotator cuff tears with and without prior failed rotator cuff repair: A large-scale comparative analysis.

Background: Large-scale data assessing the effect of a prior failed rotator cuff repair (RCR) on the outcome of reverse shoulder arthroplasty (RSA) is currently lacking. Therefore, this study aimed (1) to assess the course of patients undergoing RCR, specifically focusing on the need for conversion to RSA within two years, and (2) to compare outcomes following RSA performed for rotator cuff tears (RCTs) with and without prior RCR. Methods: This retrospective cohort study included data from the CMS Data Set (2016-2018). For the first study objective, we included patients undergoing an RCR; these were followed for 24 months to identify a conversion to RSA. For the second study objective, we included RSAs for RCTs, stratified by those with and without a prior RCR (preceding 24 months). Outcomes (hospitalization cost, institutional post-acute care discharge, 90-day readmission and health resource utilization up to 6 months post-RSA) were compared between propensity score-matched groups. Results: Out of 33,244 RCRs, 433 (1.3%) patients underwent RSA conversion within two years. Among 7534 RSA cases for RCTs, 245 (3.3%) had an RCR in the preceding two years. In the propensity score analysis, except for a minimal increase in the number of physical rehabilitation visits (RR 1.10; p = 0.0009), no differences were observed between those with and without prior RCR in terms of other RSA outcomes. These included hospitalization cost, discharge to institutional post-acute care facility, 90-day readmission and 6-month post-op cost. Conclusion: Rotator cuff repair in elderly patients, when utilizing currently employed indication criteria, results in low conversion rates to RSA within 2 years postoperatively. Furthermore, large dataset outcomes after RSA for RCT such as cost, post-acute care discharge, physical rehabilitation, and readmission rates appear not to be negatively affected by the presence of a prior RCR. Level of evidence: Level 3 evidence; Retrospective cohort study.

Outpatient versus inpatient total shoulder arthroplasty: A cost and outcome comparison in a comorbidity matched analysis.

BACKGROUND: Previous studies comparing total and reverse shoulder arthroplasty (TSA/RSA) are subject to surgeon selection bias. This study objective is to compare the outcomes and cost of outpatient TSA/RSA to inpatient TSA/RSA. METHODS: 108,889 elective inpatient and outpatient TSA/RSA from Medicare claims data (2016-2018). 90-day readmission and total 90-day costs were compared following propensity score matching. RESULTS: Younger and healthier patients are receiving outpatient TSA/RSA. Outpatient TSA/RSA was associated with fewer 90-day readmissions (OR 0.48 CI 0.38-0.59, p < 0.001) and lower 90-day costs (-20.1% CI -19.1%; -21.1%, p < 0.001). CONCLUSIONS: Outpatient TSA/RSA surgery offers lower complication rates and total costs. LEVEL OF EVIDENCE: III.

Administration of tranexamic acid during total shoulder arthroplasty is not associated with increased risk of complications in patients with a history of thrombotic events.

INTRODUCTION: Tranexamic acid (TXA) has been shown to reduce blood loss and transfusion risk in various orthopedic surgeries including shoulder arthroplasty. However, concerns still exist regarding its use in patients with a history of thrombotic events. Using national claims data, we aimed to study the safety of TXA administration in shoulder arthroplasty patients with a history of thrombotic events. METHODS: We used retrospective national claims data (Premier Healthcare) on 71,174 patients who underwent a total or reverse shoulder arthroplasty between 2010 and 2016. TXA use was evaluated specifically within a subgroup of patients with a history of thrombotic events such as myocardial infarction, deep venous thrombosis, pulmonary embolism, transient ischemic attack, or ischemic stroke. Studied outcomes were blood transfusion need, complications (including acute renal failure, new onset myocardial infarction, deep venous thrombosis, pulmonary embolism, transient ischemic attack, or ischemic stroke), and cost and length of hospitalization. Mixed-effects models measured the association between TXA use and outcomes, separately in patients with and without a history of thrombotic events. Odds ratios (OR) or percent change for continuous outcomes with 95% confidence intervals (CI) were reported. RESULTS: Overall, TXA was used in 13.7% (n = 9735) of patients, whereas 10.5% (n = 7475) of patients had a history of a thrombotic event. After adjustment for relevant covariates, TXA use (compared with no TXA use) in patients without a history of thrombotic events was associated with decreased odds of blood transfusions (OR, 0.48; CI, 0.24-0.98; P = .0444), whereas no increased odds for complications were observed (OR, 0.83; CI, 0.40-1.76; P = .6354). Similar results were observed in patients with a history of thrombotic events. Moreover, in this subgroup, TXA use was associated with a slight reduction in hospitalization cost (-8.9% CI: -13.1%; -4.6%; P < .0001; group median $18,830). CONCLUSIONS: Among shoulder arthroplasty patients, TXA use was not associated with increased complication odds, independent of a history of thrombotic events. These findings are in support of wider TXA use.

Incidental Asymptomatic Fibular Stress Fractures Presenting as Varus Knee Osteoarthritis: A Case Report.

Stress fractures are often missed, especially in unusual clinical settings. We report on 2 patients who presented to our orthopedic surgery clinic with incidental findings of asymptomatic proximal fibular tension side stress fractures in severe longstanding varus osteoarthritic knees. Initial plain films demonstrated an expansile deformity of the proximal fibular shaft, and differential diagnosis included a healed or healing fracture versus possible neoplasm. Magnetic resonance imaging with and without gadolinium was utilized to rule out the latter prior to planned total knee arthroplasty.

Restriction of Postoperative Joint Loading in a Murine Model of Anterior Cruciate Ligament Reconstruction: Botulinum Toxin Paralysis and External Fixation.

Control of knee motion in small animal models is necessary to study the effect of mechanical load on the healing process. This can be especially challenging in mice, which are being increasingly used for various orthopedic reconstruction models. We explored the feasibility of botulinum toxin (Botox; Allergan, Dublin, Ireland) paralysis and a newly designed external fixator to restrict motion of the knee in mice undergoing anterior cruciate ligament (ACL) reconstruction. Nineteen C57BL/6 mice were allocated to two groups: (1) Botox group (n = 9) and (2) external fixator group (n = 10). Mice in Botox group received two different doses of Botox: 0.25 unit (n = 3) and 0.5 unit (n = 6). Injection was performed 72 hours prior to ACL reconstruction into the quadriceps, hamstring, and calf muscles of the right hind leg. Mice in external fixator group received an external fixator following ACL reconstruction. Mice were monitored for survival, tolerance, and achievement of complete knee immobilization. All mice were meant for sacrifice on day 14 postoperatively. No perceptible change in gait was observed with 0.25 unit of Botox. All mice that received 0.5 unit of Botox had complete hind limb paralysis documented by footprint analysis 2 days after injection but failed to tolerate anesthesia and were euthanized 24 hours after operation due to their critical condition. In contrast, the external fixator was well tolerated and effectively immobilized the limb. There was a single occurrence of intraoperative technical error in the external fixator group that led to euthanasia. No mechanical failure or complication was observed. Botox paralysis was not a viable option for postoperative restriction of motion and joint loading in mice. However, external fixation was an effective method for complete knee immobilization and can be used in murine models requiring postoperative control of knee loading. This study introduces a robust research tool to allow control of postoperative joint loading in animal models such as ACL reconstruction, permitting study of the effects of mechanical load on the biologic aspects of tendon-to-bone healing.

Review of current understanding of post-traumatic osteoarthritis resulting from sports injuries.

Certain types of joint injuries, common in athletes, are known to have a high association with the development of osteoarthritis (OA). Post-traumatic osteoarthritis (PTOA) is especially debilitating due to its earlier onset than traditional OA, and its predisposition to affect a younger and more active population. Five common athletic injuries have been demonstrated to be risk factors for the development of OA. These include ACL rupture, meniscus tear, glenohumeral instability, patellar dislocation, and ankle instability. Though the mechanisms responsible for the development of PTOA are not entirely clear, certain kinematic, biologic, and mechanical factors have been implicated. In addition, there has been an increased emphasis on development of new methods to detect early OA changes in patients with known risk factors, as early intervention may prevent the development of end-stage OA. New imaging modalities as well as the identification of specific biomarkers may allow earlier detection. Though these developments hold promise, it is not entirely known what steps we can take today to prevent the future development of OA, even with early detection. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:397-405, 2017.

Involvement of Indian hedgehog signaling in mesenchymal stem cell-augmented rotator cuff tendon repair in an athymic rat model.

BACKGROUND: Bone marrow aspirate has been used in recent years to augment tendon-to-bone healing, including in rotator cuff repair. However, the healing mechanism in cell-based therapy has not been elucidated in detail. METHODS: Sixteen athymic nude rats were randomly allocated to 2 groups: experimental (human mesenchymal stem cells in fibrin glue carrier) and control (fibrin glue only). Animals were sacrificed at 2 and 4 weeks. Immunohistochemical staining was performed to evaluate Indian hedgehog (Ihh) signaling and SOX9 signaling in the healing enthesis. Macrophages were identified using CD68 and CD163 staining, and proliferating cells were identified using proliferating cell nuclear antigen staining. RESULTS: More organized and stronger staining for collagen II and a higher abundance of SOX9+ cells were observed at the enthesis in the experimental group at 2 weeks. There was significantly higher Gli1 and Patched1 expression in the experimental group at the enthesis at 2 weeks and higher numbers of Ihh+ cells in the enthesis of the experimental group vs control at both 2 weeks and 4 weeks postoperatively. There were more CD68+ cells localized to the tendon midsubstance at 2 weeks compared with 4 weeks, and there was a higher level of CD163 staining in the tendon midsubstance in the experimental group than in the control group at 4 weeks. CONCLUSION: Stem cell application had a positive effect on fibrocartilage formation at the healing rotator cuff repair site. Both SOX9 and Ihh signaling appear to play an important role in the healing process.

The Effect of Purified Human Bone Marrow-Derived Mesenchymal Stem Cells on Rotator Cuff Tendon Healing in an Athymic Rat.

PURPOSE: To evaluate the ability of purified human bone marrow-derived mesenchymal stem cells (MSCs) to augment healing of an acute small- to medium-sized rotator cuff repair in a small-animal model, evaluating the structure and composition of the healing tendon-bone interface with histologic and biomechanical analyses. METHODS: Fifty-two athymic rats underwent unilateral detachment and transosseous repair of the supraspinatus tendon augmented with either fibrin glue (control group) or fibrin glue with 106 human MSCs (experimental group) applied at the repair site. Flow cytometry verified the stem cell phenotype of the cells as CD73+, CD90+, CD105+, CD14-, CD34-, and CD45-. Rats were killed at 2 and 4 weeks, with 10 from each group used for biomechanical testing and 3 for histologic analysis. RESULTS: Safranin O staining identified increased fibrocartilage formation at the repair site at 2 weeks in the human MSC group (18.6% ± 2.9% vs 9.1% ± 1.6%, P = .026). Picrosirius staining identified decreased energy (36.88 ± 4.99 J vs 54.97 ± 8.33 J, P = .04) and increased coherence in the human MSC group (26.96% ± 15.32% vs 14.53% ± 4.10%, P = .05), indicating improved collagen orientation. Biomechanical testing showed a significant increase in failure load (11.5 ± 2.4 N vs 8.5 ± 2.4 N, P = .002) and stiffness (7.1 ± 1.2 N/mm vs 5.7 ± 2.1 N/mm, P < .001) in the experimental group compared with the control group at 2 weeks. These effects dissipated by 4 weeks, with no significant differences in fibrocartilage formation (35% ± 5.0% vs 26.6% ± 0.6%, P = .172) or biomechanical load to failure (24.6 ± 7.1 N vs 21.5 ± 4.1 N, P = .361) or stiffness (13.5 ± 3.1 N/mm vs 16.1 ± 5.6 N/mm, P = .384). All failures occurred at the bone-tendon interface. CONCLUSIONS: Rotator cuff repair augmentation with purified human MSCs improved early histologic appearance and biomechanical strength of the repair at 2 weeks, although the effects dissipated by 4 weeks with no significant differences between groups. CLINICAL RELEVANCE: Human MSCs may improve early rotator cuff healing during the first 2 weeks after repair.

Indian hedgehog signaling and the role of graft tension in tendon-to-bone healing: Evaluation in a rat ACL reconstruction model.

The structure and composition of the native enthesis is not recapitulated following tendon-to-bone repair. Indian Hedgehog (IHH) signaling has recently been shown to be important in enthesis development in a mouse model but no studies have evaluated IHH signaling in a healing model. Fourteen adult male rats underwent ACL reconstruction using a flexor tendon graft. Rats were assigned to two groups based on whether or not they received 0N or 10N of pre-tension of the graft. Specimens were evaluated at 3 and 6 weeks post-operatively using immunohistochemistry for three different protein markers of IHH signaling. Quantitative analysis of staining area and intensity using custom software demonstrated that IHH signaling was active in interface tissue formed at the healing tendon-bone interface. We also found increased staining area and intensity of IHH signaling proteins at 3 weeks in animals that received a pre-tensioned tendon graft. No significant differences were seen between the 3-week and 6-week time points. Our data suggests that the IHH signaling pathway is active during the tendon-bone healing process and appears to be mechanosensitive, as pre-tensioning of the graft at the time of surgery resulted in increased IHH signaling at three weeks.