Clinical and radiologic outcomes in patients with meniscal root tears.

BACKGROUND: Meniscal root tears can lead to early knee osteoarthritis and pain. This study aimed (1) to compare clinical and radiological outcomes between patients who underwent arthroscopic meniscal root repair after meniscal root tears and those who received non-surgical treatment, and (2) to identify whether baseline MRI findings could be potential predictors for future treatment strategies. METHODS: Patients with meniscal root tears were identified from our picture archiving and communication system from 2016 to 2020. Two radiologists reviewed radiographs and MRI studies using Kellgren-Lawrence (KL) grading and a modified Whole Organ MRI Scoring (WORMS) at baseline and follow-up. The median (interquartile range [IQR]) of follow-up radiographs and MRI studies were 134 (44-443) days and 502 (260-1176) days, respectively. MR images were assessed for root tear-related findings. Pain scores using visual analogue scale (VAS) and management strategies (non-surgical vs. arthroscopic root repair) were also collected. Chi-squared tests and independent t-tests were used to assess differences regarding clinical and imaging variables between treatment groups. Logistic regression analyses were performed to evaluate the associations between baseline MRI findings and each future treatment. RESULTS: Ninety patients were included. VAS pain scores were significantly (p < 0.01) lower after arthroscopic repair compared to conservative treatment (1.27±0.38vs.4±0.52) at the last follow-up visit with median (IQR) of 325 (180-1391) days. Increased meniscal extrusion (mm) was associated with higher odds of receiving non-surgical treatment (OR = 1.65, 95%CI 1.02-2.69, p = 0.04). The odds of having arthroscopic repair increased by 19% for every 1 mm increase in the distance of the tear from the root attachment (OR = 1.19, 95% CI: 1.05-1.36, p < 0.01). The odds of undergoing arthroscopic repair were reduced by 49% for every 1 mm increase in the extent of meniscal extrusion (OR = 0.51, 95% CI: 0.29-0.91, p = 0.02) as observed in the baseline MRI. CONCLUSIONS: Patients who underwent arthroscopic repair had lower pain scores than patients with conservative treatment in the follow-up. Distance of the torn meniscus to the root attachment and the extent of meniscal extrusion were significant predictors for arthroscopic repair in the next three weeks (time from the baseline MRI to the surgery date).

Degenerative medial and lateral menisci root tears: demographics, clinical presentation, imaging features, and associated findings.

PURPOSE: (I) Characterize the demographics and clinical features of patients with meniscal root tears (MRT); (II) analyze the morphology, extent, and grade of MRT on MRI; (III) evaluate associated abnormalities on imaging; and (IV) evaluate the associations between imaging findings, demographics, clinical features, and joint structural abnormalities. MATERIAL AND METHODS: A search was performed to identify meniscal root tears. Age, sex, BMI, and pain were recorded. Knee radiographs and MRI were reviewed. Presence, grade and morphology of MRT, meniscal extrusion, insufficiency fractures, as well as joint structural abnormalities were scored. For goals (I), (II), and (III), tabulations for categorical variables and mean for continuous variables were computed. MRT findings variables were described using percentages. For goal (IV), adjusted linear and logistic regression were employed. RESULTS: Ninety-six patients with a mean age of 56.6 years (69 females) and mean BMI of 28.9 kg/m2 were included; 88 of the MRT were located at the posterior horn of the medial meniscus (PHMM), and 82% were radial tear. The mean tear diameter was 3.8 mm, and 78/96 tears presented with meniscal extrusion. Nineteen patients presented with subchondral insufficiency fracture (SIF), which was significantly associated with the gap of the tear (p = 0.001) and grade of the meniscal root lesion (p = 0.005). CONCLUSION: MRT typically found in middle-aged to older overweight and obese women. Lesions were mostly radial tears and located at PHMM and were frequently associated with meniscal extrusion and SIF. Moreover, the presence of SIF was significantly associated with the gap width and grade of root tear.

No Differences in 2-Year Reoperation Rates for Meniscus Allograft Transplant With Concomitant Cartilage Restoration or Osteotomy: A National Database Study.

PURPOSE: To investigate reoperation rates after meniscus allograft transplant (MAT), comparing rates with and without concomitant articular cartilage and osteotomy procedures using a national insurance claims database. METHODS: We performed a retrospective cohort study of patients who underwent MAT from 2010 to 2021 with minimum 2 year follow-up using the PearlDiver database. Using Current Procedural Terminology (CPT) and International Classification of Diseases (ICD) codes, we identified patients who underwent concomitant procedures including chondroplasty or microfracture, cartilage restoration defined as osteochondral graft or autologous chondrocyte implantation (ACI), or osteotomy. Univariate logistic regressions identified risk factors for reoperation. Reoperations were classified as knee arthroplasty, interventional procedures, or diagnostic or debridement procedures. RESULTS: 750 patients were included with an average age of 29.6 years (interquartile range 21.0-36.8) and average follow-up time was 5.41 years (SD: 2.51). 90-day, 2-year, and all-time reoperation rates were 1.33%, 14.4%, and 27.6% respectively. MAT with cartilage restoration was associated with increased reoperation rate at 90 days (OR: 4.88; 95% CI: 1.38-19.27; p=.015), however there was no significant difference in reoperation rates at 2 years or to the end of follow-up. ACI had increased reoperation rates at 90 days (OR: 6.95; 95% CI: 1.45-25.96; p=.006), with no difference in reoperation rates 2 years post-operatively or to the end of follow-up. Osteochondral autograft and allograft were not associated with increased reoperation rates. CONCLUSION: 14.4% of patients in our cohort had a reoperation within 2 years of MAT. Nearly one in four patients undergoing MAT had concomitant cartilage restoration, showing that it is commonly performed on patients with articular cartilage damage. Concomitant osteochondral autograft, osteochondral allograft, chondroplasty, microfracture and osteotomy were not associated with any significant difference in reoperation rates. ACI was associated with increased reoperation rates at 90 days, but not later.

Concomitant Medial Collateral Ligament Injury Increases the Risk of Revision Anterior Cruciate Ligament Reconstruction.

PURPOSE: To compare rates of revisions between patients with isolated ACL reconstruction to those who had concomitant MCL injuries managed either operatively or non-operatively at time of index ACL reconstruction (ACLR). METHODS: The PearlDiver-Mariner Database was queried for all patients who underwent ACLR between 2016-2020 using laterality-specific International Classification of Diseases, Tenth Revision (ICD-10) and Current Procedural Terminology (CPT) codes. Patients were included if they were ages 15 or higher and had a minimum of 2 years follow-up after index ACLR. Patients were then divided into cohorts by presence or absence of concomitant MCL injury. The cohort of concomitant MCL injuries was further subdivided into those with MCL injuries managed non-operatively, with MCL repair, or with MCL reconstruction at time of index ACLR. Multivariate regression was performed between cohorts to evaluate for factors associated with revision ACLR. RESULTS: We identified 47,306 patients with isolated ACL injuries and 10,846 with concomitant MCL and ACL injuries. 93% of patients with concomitant MCL injuries had their MCL treated non-operatively; however, the annual proportion of patients being surgically managed for their MCL injury increased by 70% from 2016-2020. Concomitant MCL injury patients had higher odds of undergoing revision ACLR compared to patients with isolated ACL injuries (OR:1.50, 95%CI: 1.36-1.66, p<0.001). Amongst patients with concomitant MCL injuries, surgically managed patients had higher risk of revision ACLR compared to non-operatively managed MCL injuries (OR:1.39, 95%CI:1.01-1.86, p=0.034). CONCLUSIONS: Despite an increase in operatively managed concomitant MCL injuries, the majority of concomitant MCL injuries are still managed non-operatively at time of ACLR. Patients with concomitant MCL injury, particularly those managed operatively, at the time of ACLR are at increased risk of requiring revision ACLR compared to those with isolated ACL injuries.

How to Recognize, Correct, and Avoid Intraoperative Complications During Anterior Cruciate Ligament Reconstructions.

Technical complications are a leading cause of graft failure following anterior cruciate ligament reconstructions. Complications can occur during any phase of the procedure, from graft harvesting to tunnel preparation to graft fixation. Predicting potential causes of technical difficulty and developing strategies to avoid potential pitfalls can limit the number of intraoperative complications. If adverse events do occur intraoperatively, prompt recognition and treatment can lead to favorable outcomes. It is important to discuss strategies to understand potential complications and develop tactics to avoid and correct adverse events that can occur during anterior cruciate ligament reconstruction.

Incidence, risk factors, and complications of acromial stress fractures after reverse total shoulder arthroplasty.

BACKGROUND: An acromial stress fracture (ASF) is an uncommon complication after reverse total shoulder arthroplasty (RTSA) that can have severe clinical consequences on shoulder function. Although patient-specific factors have been identified to influence the risk of ASF, it is unclear whether modifying these factors can minimize risk. Moreover, there is limited information on the treatment outcomes of these fractures. Therefore, the purpose of this study was to determine modifiable risk factors for ASFs and the complication and revision rates of conservatively and operatively managed ASFs. METHODS: The PearlDiver database was queried to identify a cohort of patients who underwent RTSA with minimum 2-year follow-up. Current Procedural Terminology and International Classification of Diseases codes were used to compare the demographic characteristics, comorbidities, and medication use of patients with and without ASFs. Surgical complication and revision rates were compared between operatively and conservatively treated fractures. RESULTS: The overall incidence of ASFs was 1.4%. Patient-specific factors that were independently associated with the occurrence of an ASF included osteoporosis, rheumatologic disease, shoulder corticosteroid injection within 3 months before surgery, and chronic oral corticosteroid use. Among patients with osteoporosis, the initiation of physical therapy within 6 weeks after surgery also increased the risk of ASF. Patients who underwent surgical treatment of ASFs had a revision arthroplasty rate of 7.0% compared to a rate of 3.2% among those with conservatively managed fractures. CONCLUSION: ASFs are infrequent complications that can occur after RTSA. Preoperative factors that affect the quality of bone independently increase the fracture risk. Moreover, this risk can be minimized by avoiding shoulder corticosteroid injections 3 months before surgery and delaying physical therapy exercises among patients with osteoporosis. Surgical fixation of these fractures should be reserved for instances when conservative management has failed given high rates of infection, instability, and revision shoulder arthroplasty.

Overexpression of PRDM16 Improves Muscle Function after Rotator Cuff Tears.

INTRODUCTION: Muscle atrophy, fibrosis and fatty infiltration (FI) are commonly seen in rotator cuff tears (RCT), which are critical factors that directly determine the clinical outcomes for patients with this injury. Therefore, improving muscle quality after RCT is crucial in improving the clinical outcome of tendon repair. In recent years, it has been discovered that adults have functional beige/brown adipose tissue (BAT) which can secrete batokines to promote muscle growth. PRDM16, a PR-domain containing protein, was discovered with the ability to determine the brown fat cell fate and stimulate its development. Thus, the goal of this study is to discover the role of PRDM16 in improving muscle function after massive tendon tears using a transgenic mouse model with an elevated level of PRDM16 expression. METHODS: Transgenic aP2 driven PRDM16 overexpression mice and C57BL/6J mice underwent unilateral supraspinatus (SS) tendon transection and suprascapular nerve transection (TTDN) as described previously (N=8 in each group). DigiGait was performed to evaluate forelimb function at 6 weeks post the TTDN injury. Bilateral SS muscles, interscapular brown fat, epididymal white fat, and inguinal beige fat were harvested for analysis. The expression of PRDM16 in adipose tissue was detected by Western Blot. Masson's trichome staining was conducted to evaluate the muscle fibrosis and Oil Red O staining was used to determine the fat infiltration. Muscle fiber type was determined by MHC expression via immunostaining. All data was presented in the form of mean±SD. T-test and two-way ANOVA analysis was performed to determine a statistically significant difference between groups. Significance was considered when P<0.05. RESULTS: Western blot data showed an increased expression of PRDM16 protein in both white and brown fat in PRDM16-overexpression mice compared to wild-type (WT) mice. Even though PRDM16 overexpression had no effect on increasing muscle weight, it significantly improved the forelimbs function with longer brake, stance and stride time, larger stride length and paw area in mice after RCT. Additionally, PRDM16 overexpression mice showed no difference in amount of fibrosis when compared to WT mice, however, they had significantly reduced area of fatty infiltration. These mice also exhibited abundant MHC-IIx fiber percentage in supraspinatus muscle after TTDN. CONCLUSION: Overexpression of PRDM16 significantly improved muscle function and reduced fatty infiltration after rotator cuff tears. Promoting BAT activity is beneficial in improving rotator cuff muscle quality and shoulder function after RCT.

Utilization of Autologous Chondrocyte Implantation in the Knee Is Increasing While Reoperation Rates Are Decreasing Despite Increasing Preoperative Comorbidities.

PURPOSE: The primary purpose of this study was to assess the use of autologous chondrocyte implantation (ACI) procedures in the knee during last decade, and the secondary aims of the study were to determine reoperation rates after ACI and to identify associated risk factors. METHODS: A retrospective cohort study from 2010-2020 was performed using the PearlDiver database. The database was queried for the Current Procedural Terminology (CPT) code for ACI performed in any knee location, including the patellofemoral and tibiofemoral joints. Reoperation was defined as interventional knee procedures or total knee arthroplasty after ACI. Reoperations were identified using CPT and International Classification of Diseases codes. Univariate and multivariate logistic regression were used to identify risk factors for reoperation. Significance was defined as P < .05. RESULTS: Among the 2010 patients included in this study, there were 90-day and overall reoperation rates of 2.24% and 30.4%, respectively, with an average follow up of 4.8 ± 3.3 years. The most common reoperations included chondroplasty, meniscectomy, and microfracture. There was an increased rate of ACI performed from 2017-2019 (5.53/100,000) compared to 2014-2016 (4.16/100,000; P < .001). ACI surgeries performed in 2017-2019 were associated with decreased risk of reoperation within 2 years relative to 2014-2016 (odds ratio [OR] = 0.70; 95% confidence interval [CI], 0.52-0.94; P = .019). In the entire ACI cohort, older age (OR = 1.07; 95% CI, 1.05-1.09; P < .001) and tobacco use (OR = 2.13; 95% CI, 1.06-3.94; P = .022) were associated with increased risk of conversion to arthroplasty. Male sex was associated with decreased overall reoperation rates (OR = 0.73; 95% CI, 0.60-0.89; P = .002). CONCLUSIONS: There has been increasing use of ACI in the knee with decreased risk of reoperation since 2017 and the introduction of matrix-associated autologous chondrocyte implantation. Older age and tobacco use were predictors of increased risk of conversion to arthroplasty. Male sex was associated with decreased risk of reoperation. LEVEL OF EVIDENCE: Level IV, retrospective cohort design; database study.

Pre-existing Mental Health Diagnoses Are Associated With Higher Rates of Postoperative Complications, Readmissions, and Reoperations Following Arthroscopic Rotator Cuff Repair.

PURPOSE: To investigate the association between preoperative mental health disorders and postoperative complications, readmissions, and ipsilateral revision procedures among patients undergoing arthroscopic rotator cuff repair (RCR). METHODS: A retrospective cohort study from 2010 to 2020 was performed using the PearlDiver database. Current Procedural Terminology and International Classification of Diseases codes were used to compare patients with and without mental health disorders who underwent arthroscopic RCR. Mental health disorders evaluated in this study include depressive disorder, major depressive disorder, major depressive affective disorder, bipolar disorder, dysthymic disorder, adjustment disorder, separation anxiety disorder, and posttraumatic stress disorder. Patients were matched at a 1:1 ratio based on age, sex, Charlson Comorbidity Index, body mass index, and tobacco use. Rates of complications and subsequent surgeries were compared between patients with and without a preoperative diagnosis of a mental health disorder. RESULTS: The 1-year preoperative prevalence of a mental health disorder from 2010 to 2020 was 14.6%. After 1:1 matching, patients with a mental health disorder who underwent arthroscopic RCR were nearly twice as likely to undergo a revision procedure (odds ratio 1.94, 95% confidence interval 1.76-2.14, P < .001) and more than twice as likely to experience conversion to shoulder arthroplasty (odds ratio 2.29, 95% confidence interval 1.88-2.80, P < .001) within 2 years of initial arthroscopy when compared with patients without a mental disorder. Patients with a mental disorder also experienced increased risk for 90-day readmission (1.9% vs 0%, P < .001) as well as multiple postoperative medical complications. CONCLUSIONS: Patients with pre-existing mental health diagnoses experience increased rates of 90-day postoperative complications and readmissions following arthroscopic RCR. In addition, patients with mental health diagnoses are more likely to undergo revision repair and conversion to shoulder arthroplasty within 2 years of the index procedure. LEVEL OF EVIDENCE: Level III.

Incidence of Venous Thromboembolism After Hip Arthroscopy Is Low With or Without Prophylaxis but Risk Factors Include Oral Contraceptive Use, Obesity, and Malignancy.

PURPOSE: To determine the incidence of and risk factors for symptomatic venous thromboembolism (VTE) after hip arthroscopy (HA) and thromboprophylaxis prescription utilization for this procedure. METHODS: The PearlDiver Mariner database was queried using Current Procedural Terminology codes to identify adult patients (aged ≥ 18 years) who underwent HA between 2010 and 2020. Patient demographic information, including age, oral contraceptive use, and medical comorbidities, as well as perioperative thromboprophylaxis utilization, was recorded using International Classification of Diseases codes and National Drug Codes. The incidence of postoperative VTE within 90 days was determined. Multivariate logistic regression was used to identify predictors of perioperative thromboprophylaxis utilization and risk factors for VTE. RESULTS: The queried records identified 60,181 patients who met the inclusion criteria. Of these patients, 367 (0.6%) experienced VTE, including deep venous thrombosis (0.5%) and/or pulmonary embolism (0.2%). Approximately 2.1% of patients used thromboprophylaxis, including aspirin (1.1%), low-molecular-weight heparin (0.9%), and oral factor Xa inhibitors (0.1%). Oral contraceptive pill use (adjusted odds ratio [aOR], 2.16; 95% confidence interval [CI], 1.34-3.46), obesity (aOR, 1.37; 95% CI, 1.05-1.79), and a history of malignancy (aOR, 1.69; 95% CI, 1.12-2.54) were associated with increased odds of experiencing VTE. Perioperative thromboprophylaxis (aOR, 0.52; 95% CI, 0.19-1.39) was not significantly associated with decreased odds of experiencing VTE. However, obesity (aOR, 1.17; 95% CI, 1.00-1.38) and hypertension (aOR, 1.17; 95% CI, 1.02-1.36) were associated with increased odds of thromboprophylaxis prescription utilization. CONCLUSIONS: Although the overall risk of symptomatic VTE after HA remains low, oral contraceptive use, obesity, and a history of malignancy are associated with increased odds of thromboembolic events within 90 days. Routine thromboprophylaxis after HA may not be indicated in all patients but can be considered based on patient-specific risk factors. LEVEL OF EVIDENCE: Level III, retrospective prognostic comparative trial.

Complications and re-operations after extensor mechanism repair surgery in a large cross-sectional cohort: females and tobacco-users at highest risk for adverse outcomes.

PURPOSE: There is little information on patients most at risk for poor outcomes following surgical repair of extensor mechanism tendon injuries. The purpose of this study is to provide an epidemiological overview of patients undergoing patellar or quadriceps tendon repair and to assess the incidence of postoperative complications, readmissions, and revision repairs among this population. METHODS: Retrospective data were obtained using the PearlDiver database for patellar tendon repair and quadriceps tendon repair patients between 2010 and 2020. Baseline demographics, incidences of 90-day readmissions and postoperative complications, and reoperation rates were collected for each group. Multivariate logistic regression was performed to assess the predictive power of each demographic variable on the incidence of postoperative complications and reoperations. RESULTS: In total, 1543 patients underwent patellar tendon repair and 601 underwent quadriceps tendon repair. Complications within 90-days were observed in 33.7% of patients with patellar tendon repair and 39.2% of patients with quadriceps tendon repair. Reoperation rates were 4.2% and 4.8% for patellar tendon repair and quadriceps tendon repair, respectively. Females in both patellar tendon repair and quadriceps tendon repair groups were at significantly higher risk for post-operative complications (patellar tendon repair OR 3.0, 95% CI 2.4-3.7; quadriceps tendon repair OR 2.9, 95% CI 1.9-4.6; p < 0.001 for both). Older age (p < 0.001), female gender (p < 0.001), CCI (p < 0.001), tobacco use (p < 0.001), and obesity (p < 0.01) were all predictors of experiencing at least one complication following patellar tendon repair. For quadriceps tendon repair, female gender (p < 0.001) and CCI (p < 0.001) were the strongest predictors of experiencing at least one complication, while older age, tobacco use, and obesity (p < 0.05 for all) were also significant independent predictors. CONCLUSION: Patellar tendon repair patients are younger on average than quadriceps tendon repair patients. Although females are less likely to sustain extensor mechanism ruptures compared to males, females are significantly more likely to have at least one complication after quadriceps or patellar tendon repair. These findings may be used by surgeons, patients, and payors to understand who is most at risk for adverse outcomes following extensor mechanism repair surgery, resulting in earlier intervention and counseling to reduce the likelihood of a poor outcome following extensor mechanism repair surgery. LEVEL OF EVIDENCE: Level III.

Delayed ACL reconstruction increases rates of concomitant procedures and risk of subsequent surgery.

PURPOSE: To utilise a large cross-sectional database to analyse the effects of time duration between diagnosis of anterior cruciate ligament (ACL) tear and ACL reconstruction (ACLR) on concomitant procedures performed and subsequent surgery within 2 years. METHODS: An analysis from 2015 to 2018 was performed using the Mariner PearlDiver Patient Records Database. Current Procedural Terminology (CPT), and International Classification of Diseases (ICD-10) codes identified patients with a diagnosis of ACL tear who underwent subsequent ACLR. Patients were stratified in biweekly and bimonthly increments based on the time duration between initial diagnosis of ACL tear and surgical treatment. Chi-squared analysis was used to compare categorical variables, and trend analysis was performed with Cochran-Armitage independence testing. RESULTS: Of 11,867 patients who underwent ACLR, 76.1% underwent surgery within 2 months of injury diagnosis. Patients aged 10-19 were most likely to undergo surgery within 2 months of injury diagnosis (83.5%, P < 0.0001). As duration from injury diagnosis to ACLR increased from < 2 months to > 6 months, rates of concomitant meniscectomy increased from 9.1% to 20.5% (P < 0.0001). The overall 2-year subsequent surgery rate was 5.3%. The incidence of revision ACLR was highest for patients who underwent surgery > 6 months after diagnosis (P < 0.0001), whilst the incidence of ipsilateral lysis of adhesions and manipulation under anaesthesia (MUA) was highest for patients who underwent surgery < 2 months after diagnosis (P < 0.0001). ACLR at 6-8 weeks after diagnosis demonstrated the lowest risk for concomitant procedures as well as 2-year subsequent surgery. CONCLUSION: The majority of patients undergo ACL reconstruction within 2 months of initial ACL tear diagnosis. Delayed surgery greater than 6 months after the diagnosis of an ACL rupture leads to increased need for concomitant meniscectomy as well as higher risk for revision ACLR within 2 years, but immediate surgery may increase risk for knee arthrofibrosis. LEVEL OF EVIDENCE: IV.

Effect of obesity on short- and long-term complications of shoulder arthroplasty.

BACKGROUND: The proportion of patients undergoing total shoulder arthroplasty (TSA) with obesity continues to grow every year in the United States. Although comorbid obesity is common among TSA patients, the relationship of obesity on medical and surgical complications remains debated. The goal of this study was to evaluate a national database for postoperative medical and surgical complications in patients undergoing TSA with comorbid obesity. METHODS: Patients undergoing anatomic and reverse TSA were studied in the PearlDiver database. Current Procedural Terminology (CPT) and International Classification of Diseases (ICD) codes were used to compare patients with and without preoperative obesity who underwent TSA, and they were stratified based on body mass index (BMI) into nonobese, obese, morbidly obese, and superobese. A matched comparison was performed at a 1:1 ratio based on age, sex, diabetes, smoking, tobacco use, and Charlson Comorbidity Index. RESULTS: From 2010 to 2020, a total of 113,634 patients undergoing anatomic or reverse TSA were identified in a national database. During this time, the percentage of TSA patients with obesity increased every year. Matched cohort analysis demonstrated higher odds of readmission, deep vein thrombosis and pulmonary embolism, superficial infection, and prosthetic joint infection at 90 days postoperatively in the obesity group. There were no increased odds of mechanical complications or revision surgery at 2 years in the obesity group when matched to nonobese patients with similar comorbidities. CONCLUSION: The number of patients undergoing TSA with obesity is rising. Medical complications and infection after TSA are greater in obese patients even when matching for medical comorbidities, age, and sex, and rates of complication increase as BMI increases. Obesity is not an independent risk factor for mechanical surgical complications and revision surgery, and the relatively higher rates are likely due to an increased burden of other comorbidities. Surgeons should counsel obese patients appropriately regarding their perioperative risk of medical complication, but they should not expect higher rates of mechanical complication or revision surgery at 2-year follow-up when compared to a matched control group with similar comorbidities.

Periarticular injection in addition to interscalene nerve block can decrease opioid consumption and pain following total shoulder arthroplasty: a comparison cohort study.

BACKGROUND: Interscalene nerve block (INB) is an effective technique to provide postoperative analgesia for total shoulder arthroplasty (TSA). However, the analgesic effects of the block typically resolve between 8 and 24 hours postadministration, which results in rebound pain and subsequent increased opioid use. The objective of this study was to address this issue by determining how adding an intraoperative periarticular injection (PAI) in combination with INB affects acute postoperative opioid consumption and pain scores in patients undergoing TSA. We hypothesized that compared with INB alone, INB + PAI will significantly reduce opioid consumption and pain scores for the first 24 hours postsurgery. METHODS: We reviewed 130 consecutive patients who underwent elective primary TSA at a single tertiary institution. The first 65 patients were treated with INB alone, followed by 65 patients treated with INB + PAI. The INB used was 15-20 mL of 0.5% ropivacaine. The PAI used was 50 mL of a combination of ropivacaine (123 mg), epinephrine (0.25 mg), clonidine (40 µg), and ketorolac (15 mg). The PAI was injected using a standardized protocol: 10 mL into the subcutaneous tissues prior to incision, 15 mL into the supraspinatus fossa, 15 mL at the base of the coracoid process, and 10 mL into the deltoid and pectoralis muscles-a protocol analogous with a previously described technique. For all patients, a standardized postoperative oral pain medication protocol was used. The primary outcome was acute postoperative opioid consumption represented by morphine equivalent units (MEUs), whereas the secondary outcome was visual analog scale (VAS) pain scores over the first 24 hours postsurgery, operative time, length of stay, and acute perioperative complications. RESULTS: No significant differences in demographics existed between patients who received INB alone vs. INB + PAI. Patients who received INB + PAI had a significantly lower 24-hour postoperative opioid consumption compared to the INB alone group (38.6 ± 30.5 MEU vs. 60.5 ± 37.3 MEU, P < .001). Additionally, VAS pain scores for the first 24 hours postsurgery in the INB + PAI group were significantly lower compared to those for the INB alone group (2.9 ± 1.5 vs. 4.3 ± 1.6, P ≤ .001). No differences existed between groups regarding operative time, length of inpatient stay, and acute perioperative complications. CONCLUSION: Patients undergoing TSA with INB + PAI demonstrated significantly decreased 24-hour postoperative total opioid consumption and 24-hour postoperative pain scores compared to the group treated with INB alone. No increase in acute perioperative complications related to PAI was observed. Thus, compared to an INB, the addition of an intraoperative periarticular cocktail injection appears to be a safe and effective method to reduce acute postoperative pain following TSA.

The Role of Matrix Metalloproteinase-13 (MMP13) in TGFß/BMP Pathway Regulation of Fibro-Adipogenic Progenitor (FAP) Differentiation.

BACKGROUND/AIMS: Muscle fibrosis and fatty infiltration (FI) are common complications seen in various muscle disease states. Recent studies indicate that muscle residential fibro/adipogenic progenitors (FAPs) are the major cellular source for muscle fibrosis and FI. We previously showed that MMP13 knockout (KO) mice have significantly increased FI, suggesting an important role of MMP13 in muscle FI. However, how MMP13 affects the differentiation of FAPs remains unknown. METHODS: In order to assess the role of MMP-13 on FAP differentiation, we isolated FAPs from wildtype C57BL/6 and MMP13 knock out mice with FACS using CD31-, CD45-, Integrin α7- and Sca-1+ markers. FAPs were cultured in 24 well plate after FACS.in standard media till 80% confluent and then switched to adipogenic medium. In order to study the role of TGFß and BMP in their differentiation, FAPs from both wildtype and MMP13 KO mice were treated with TGFß1 (5 ng/ml). For MMP13 inhibitor treatment, FAPs from wildtype mice were incubated in adipogenic medium containing 10 µM MMP13 inhibitor (or vehicle) for 2 weeks. Immunofluorescence and gene expression analysis were used to assess FAP adipogenic and fibrogenic differentiation. FAPs were stained with Perilipin A (FITC, adipogenesis marker) and αSMA (Red, fibroblast marker), and DAPI. Real time PCR was performed for gene expression evaluation. A two-tailed Anova was used for statistical comparisons between groups, withp ≤ 0.05. Data are presented as mean ± standard deviation. RESULTS: In this study, we isolated FAPs from wildtype C57BL/6 and MMP13 KO mice and evaluated their adipogenic and fibrogenic differentiation in vitro. MMP13 KO FAPs demonstrated enhanced adipogenesis but reduced fibrogenesis compared to wildtype FAPs. Treating wildtype FAPs with an MMP13 inhibitor simulated phenotypes seen in MMP13 KO FAPs. In order to assess the role of MMP13 on TGFß/BMP signaling in regulating FAP differentiation, we treated wildtype and MMP13 KO FAPs with TGFß1, BMP7, TGFß inhibitor, and BMP inhibitor. TGFß1 treatment significantly enhanced fibrogenesis, but inhibited adipogenesis of wildtype FAPs. However, treatment with BMP7 showed the opposite effect. Interestingly, the effect of TGFß1/BMP7 was voided in MMP13 KO FAPs. Treating wildtype FAPs with MMP13 inhibitor also abolished the effect of TGFß1/BMP7 in FAP differentiation. CONCLUSION: Results from this study showed that TGFß1 inhibits FAP adipogenesis but stimulates FAP fibrogenesis. BMP7 was shown to promote FAP adipogenesis but reduce its fibrogenesis. The role of the TGFß/BMP signaling pathway regulating FAP differentiation was found to be MMP13 dependent. This study suggests that MMP13 is a critical downstream effector in TGFß/BMP pathway which may serve as a new therapeutic target for muscle fibrosis and FI.

Editorial Commentary: Stem Cell Exosomes Can Promote Healing and Muscle Function After Rotator Cuff Repair.

Stem cell-based therapies are a growing area of interest within regenerative musculoskeletal medicine. Exosomes represent an attractive emergent clinical strategy for the delivery of stem cell-derived growth factors and small molecules to a regenerating tissue environment. Stem cells themselves may not engraft into host tissue but more likely promote a pro-regenerative state through the release of autocrine and paracrine factors. Exosomes, a type of small membrane-bound extracellular vesicle secreted by cells, are of interest as an emergent clinical strategy because they have several key factors that could provide the elusive goal of stem cell therapies in a more practical manner. Exosomes from stem cells appear to have much of the machinery that could promote regenerative capabilities, including growth factors, micro-RNAs (miRNAs), and other signaling molecules that can induce the necessary growth signaling and transcriptional changes to induce a phenotypic change in the local delivery environment. It is important to note that they also have a limited host immune response and can be stored in a freezer, as opposed to many stem cell products that need specialized storage systems to maintain viability. For these reasons, exosome-based therapeutic solutions for rotator cuff repair offer a potential treatment strategy. Recent research provides a highly translational application of exosomes to a chronic rotator cuff repair model and shows efficacy in improving the biomechanical strength of tendon healing at the tendon-bone interface, in addition to partially ameliorating the development of fatty infiltration. Further work is needed to characterize the components of exosomes that result in their bioactivity in addition to considering their cost-effectiveness as a regenerative musculoskeletal treatment.

Biceps Tenodesis Demonstrates Lower Reoperation Rates Compared to SLAP Repair for Treatment of SLAP Tears in a Large Cross-Sectional Population.

PURPOSE: To use a contemporary cross-sectional data set to evaluate trends in surgical treatment for superior labrum anterior and posterior (SLAP) tears and compare surgical outcomes with respect to 2-year revision surgery rates following index SLAP repair versus biceps tenodesis (BT). METHODS: Patients diagnosed with a SLAP tear between 2010 and 2017 were queried using the Mariner PearlDiver database and stratified by demographic variables and surgical treatment with arthroscopic SLAP repair or arthroscopic/open BT. From 2015 to 2017, Current Procedural Terminology (CPT) and International Classification of Diseases 10th revision (ICD-10) codes were used to track ipsilateral subsequent reoperation within 2-years of index surgery. RESULTS: Between 2010 to 2017, 16.6% of 377,463 patients diagnosed with a SLAP tear underwent surgery (62.3% SLAP repair vs 37.7% BT). 52.4% of BT procedures were arthroscopic (47.6% open). The frequency of SLAP repairs decreased from 74.0% to 46.2% (61%), while the frequency of BTs increased from 26.0% to 53.8% (202%) during the study period. Patients under age 50 were more likely to undergo SLAP repair, and those undergoing BT were more likely to be over 50 with higher CCI and comorbidity risk. 6.3% of 16,186 patients identified with ICD-10 coding required reoperation within 2-years postoperatively. SLAP repair demonstrated a higher revision rate (6.8%; 95% CI, 6.3-7.4%) than BT (5.7%; 95% CI, 5.2-6.2%; P =.0002), (open 5.8% vs arthroscopic BT 5.5%). Arthroscopic debridement, including biceps tenotomy, revision SLAP repair, and revision BT were the most common subsequent procedures. Patients aged 40 to 49 had the highest rate of revision surgery (7.8%). CONCLUSIONS: The treatment trend for SLAP tears is changing, with SLAP repair becoming significantly less utilized and BT now becoming the preferred option, especially in patients over 50. Arthroscopic and open BT demonstrated slightly lower risk for reoperation than SLAP repair. LEVEL OF EVIDENCE: IV, cross-sectional study.

Younger Patients Are More Likely to Undergo Arthroscopic Meniscal Repair and Revision Meniscal Surgery in a Large Cross-Sectional Cohort.

PURPOSE: To evaluate recent trends in the treatment of meniscal tears with arthroscopic repair and debridement and to assess revision surgery within 2 years using a large cross-sectional database. METHODS: Patients with a diagnosis of meniscal tear from 2010 to 2017 were queried using the Mariner data set from PearlDiver. Patient demographic data were analyzed and tracked via International Classification of Diseases, Tenth Revision codes to investigate subsequent ipsilateral meniscal procedures and conversion to total knee arthroplasty within 2 years after index meniscal surgery. RESULTS: Of the 1,383,161 patients with a diagnosis of meniscal tear, 53.0% underwent surgical treatment. Surgical treatment consisted of meniscal debridement in 96.6% of patients and meniscal repair in 3.4%. The percentage of meniscal repairs increased from 2.7% to 4.4% over the 8-year period evaluated, whereas the percentage of meniscal debridement decreased from 97.3% to 95.6% (P < .0001). Younger patients were more likely to undergo meniscal repair (23% of those aged 10-19 years) than older patients (<1% of those aged ≥60 years). Among the 191,729 patients with International Classification of Diseases, Tenth Revision coding and 2-year follow-up, 10.6% of patients with index meniscal repair required a revision meniscal operation and 1.2% underwent conversion to arthroplasty. Subsequent meniscal procedures within 2 years after index meniscal repair included meniscal debridement in 81.6% of patients and revision repair in 18.4%. Patients who initially underwent meniscal debridement were less likely to undergo revision meniscal surgery (5.1%), but 4.7% required conversion to arthroplasty. Patients aged 10 to 19 years were most likely to undergo revision meniscal procedures after both index meniscal repair (12.8%) and meniscal debridement (8.8%). CONCLUSIONS: The rate of meniscal repair is increasing over time, with patients younger than 30 years most likely to undergo repair for a meniscal tear. Revision surgery for meniscal repair or debridement is more common in adolescents and patients who undergo an index meniscal repair. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Perioperative Thromboprophylaxis Is Associated With Lower Risk of Venous Thromboembolism After Knee Arthroscopy.

PURPOSE: To determine the rate of symptomatic venous thromboembolism (VTE) among patients undergoing arthroscopic knee procedures, risk factors associated with postoperative VTE, and current perioperative thromboprophylaxis prescription patterns associated with this population in the United States. METHODS: Medical records for patients ≥18 years of age were queried from the Mariner database using Current Procedural Terminology codes for knee arthroscopy performed in the United States from 2010 to 2020 in this cross-sectional study. Patients who received thromboprophylaxis and those diagnosed with VTE, including deep-vein thrombosis or pulmonary embolism, within 90 days of surgery were identified using International Classification of Diseases and National Drug Codes. Two multivariable logistic regression models were used to identify VTE risk factors and likelihood of perioperative thromboprophylaxis. Covariates included procedure type, age, oral contraceptive pill (OCP) use, and medical comorbidities. RESULTS: A total of 718,289 patients met inclusion criteria and 7,618 patients (1.06%) experienced VTE, including deep-vein thrombosis (n = 6,394, 0.9%) and/or pulmonary embolism (n = 2,211, 0.3%). A total of 10,769 patients (1.5%) filled perioperative thromboprophylaxis, including aspirin (n = 5,353, 0.7%), low-molecular-weight heparin (n = 4,563, 0.6%), and oral factor Xa inhibitors (n = 947, 0.1%). Perioperative thromboprophylaxis was associated with decreased odds of experiencing VTE (adjusted odds ratio [aOR] 0.65, 95% confidence interval [CI] 0.51-0.80). Procedure types categorized as moderate-to-greater risk were associated with increased odds of VTE (aOR 1.42, 95% CI 1.34-1.50). OCP use (aOR 1.63, 95% CI 1.38-1.91), obesity (aOR 1.17, 95% CI 1.11-1.24), renal disease (aOR 1.33, 95% CI 1.18-1.50) and congestive heart failure (aOR 1.30, 95% CI 1.13-1.50) were associated with increased odds of VTE. CONCLUSIONS: While the overall rate of symptomatic VTE following knee arthroscopy remains low, procedure types that are more complex and generally require restrictive rehabilitation protocols, OCP use, obesity, renal disease, and congestive heart failure are associated with increased odds of postoperative VTE. Conversely, the use of perioperative thromboprophylaxis is associated with significantly lower VTE risk. LEVEL OF EVIDENCE: III, retrospective comparative prognostic trial.

Complications after high tibial osteotomy and distal femoral osteotomy are associated with increasing medical comorbidities and tobacco use.

PURPOSE: The purpose of this study was to assess complications, reoperations, and their risk factors at 90 days and 2 years after high tibial osteotomy (HTO) and distal femoral osteotomy (DFO) in a national cohort. METHODS: The PearlDiver Mariner Dataset was queried using International Classification of Diseases (ICD) and Current Procedural Terminology (CPT) codes for HTO and DFO, complications, and subsequent surgery. Minimum follow-up was 2 years and complications were assessed at 90 days and 2 years. Hospital readmission in the first 90 days was also assessed. Univariate and multiple logistic regression were utilized to identify risk factors for complications and re-operation. RESULTS: The 90-day and 2-year complication rates after HTO (n = 1780) were 11.6% and 31.7%, compared to 21.5% (p < 0.0001) and 41.5% (p = 0.0001) after DFO (n = 446). Infection was the most frequent early (90-day) complication for both HTO and DFO cohorts, while hardware problems were most common at 2 years. Increasing Elixhauser Comorbidity Index (ECI) was associated with increased odds of infection, readmission, and hardware-associated complications in both cohorts. Gender and tobacco use were also associated with various complications after HTO. At 2 years, 23.7% of HTO patients and 26.2% of DFO patients had undergone subsequent surgery. Hardware removal occurred in 16.4% of HTO and 18.4% of DFO patients (n.s.), while 4.5% of HTO and 5.2% of DFO patients underwent total knee arthroplasty (TKA) within 2 years (n.s.). CONCLUSION: HTO and DFO have substantial complication rates in the short and mid term, with a higher rate of overall complications observed after DFO as compared to the HTO cohort. After both procedures, roughly one quarter of patients will undergo subsequent surgery within 2 years. Patients with tobacco use and numerous medical co-morbidities may not be optimal candidates due to increased complication rates. Elixhauser Comorbidity Index (ECI) may be an useful tool for risk assessment prior to surgery. LEVEL OF EVIDENCE: Retrospective cohort study, III.