Hepatocellular RECK as a Critical Regulator of Metabolic Dysfunction-associated Steatohepatitis Development.

BACKGROUND & AIMS: Reversion-inducing cysteine-rich protein with Kazal motifs (RECK) is an extracellular matrix regulator with anti-fibrotic effects. However, its expression and role in metabolic dysfunction-associated steatohepatitis (MASH) and hepatic fibrosis are poorly understood. METHODS: We generated a novel transgenic mouse model with RECK overexpression specifically in hepatocytes to investigate its role in Western diet (WD)-induced liver disease. Proteomic analysis and in vitro studies were performed to mechanistically link RECK to hepatic inflammation and fibrosis. RESULTS: Our results show that RECK expression is significantly decreased in liver biopsies from human patients diagnosed with MASH and correlated negatively with severity of metabolic dysfunction-associated steatotic liver disease (MASLD) and fibrosis. Similarly, RECK expression is downregulated in WD-induced MASH in wild-type mice. Hepatocyte-specific RECK overexpression significantly reduced hepatic pathology in WD-induced liver injury. Proteomic analysis highlighted changes in extracellular matrix and cell-signaling proteins. In vitro mechanistic studies linked RECK induction to reduced ADAM10 (a disintegrin and metalloproteinase domain-containing protein 10) and ADAM17 activity, amphiregulin release, epidermal growth factor receptor activation, and stellate cell activation. CONCLUSION: Our in vivo and mechanistic in vitro studies reveal that RECK is a novel upstream regulator of inflammation and fibrosis in the diseased liver, its induction is hepatoprotective, and thus highlights its potential as a novel therapeutic in MASH.

Is ChatGPT a trusted source of information for total hip and knee arthroplasty patients?

Aims: While internet search engines have been the primary information source for patients' questions, artificial intelligence large language models like ChatGPT are trending towards becoming the new primary source. The purpose of this study was to determine if ChatGPT can answer patient questions about total hip (THA) and knee arthroplasty (TKA) with consistent accuracy, comprehensiveness, and easy readability. Methods: We posed the 20 most Google-searched questions about THA and TKA, plus ten additional postoperative questions, to ChatGPT. Each question was asked twice to evaluate for consistency in quality. Following each response, we responded with, "Please explain so it is easier to understand," to evaluate ChatGPT's ability to reduce response reading grade level, measured as Flesch-Kincaid Grade Level (FKGL). Five resident physicians rated the 120 responses on 1 to 5 accuracy and comprehensiveness scales. Additionally, they answered a "yes" or "no" question regarding acceptability. Mean scores were calculated for each question, and responses were deemed acceptable if ≥ four raters answered "yes." Results: The mean accuracy and comprehensiveness scores were 4.26 (95% confidence interval (CI) 4.19 to 4.33) and 3.79 (95% CI 3.69 to 3.89), respectively. Out of all the responses, 59.2% (71/120; 95% CI 50.0% to 67.7%) were acceptable. ChatGPT was consistent when asked the same question twice, giving no significant difference in accuracy (t = 0.821; p = 0.415), comprehensiveness (t = 1.387; p = 0.171), acceptability (χ2 = 1.832; p = 0.176), and FKGL (t = 0.264; p = 0.793). There was a significantly lower FKGL (t = 2.204; p = 0.029) for easier responses (11.14; 95% CI 10.57 to 11.71) than original responses (12.15; 95% CI 11.45 to 12.85). Conclusion: ChatGPT answered THA and TKA patient questions with accuracy comparable to previous reports of websites, with adequate comprehensiveness, but with limited acceptability as the sole information source. ChatGPT has potential for answering patient questions about THA and TKA, but needs improvement.

Karyopherins in the Remodeling of Extracellular Matrix: Implications in Tendon Injury.

Rotator Cuff Tendinopathies (RCT) are debilitating conditions characterized by alterations in the extracellular matrix (ECM) of the shoulder tendon, resulting in pain, discomfort, and functional limitations. Specific mediators, including HIF-1α, TGF-ß, MMP-9 and others have been implicated in the morphological changes observed in the tendon ECM. These mediators rely on karyopherins, a family of nuclear proteins involved in nucleo-cytoplasmic transport; however, the role of karyopherins in RCT remains understudied despite their potential role in nuclear transport mechanisms. Also, the understanding regarding the precise contributions of karyopherins in RCT holds great promise for deciphering the underlying pathophysiological mechanisms of the disease and potentially fostering the development of targeted therapeutic strategies. This article critically discusses the implications, possibilities, and perspectives of karyopherins in the pathophysiology of RCT.

Baseball Pitchers who Suffer Latissimus Dorsi and Teres Major Tendon Injuries Have a High Return to Play Rate After Either Operative or Nonoperative Treatment.

Purpose: To provide a concise overview of the prevalence, diagnostic workup, management options, surgical techniques, and reported outcomes in the treatment of latissimus dorsi (LD) and teres major (TM) injuries in professional baseball pitchers. Methods: A systematic review of studies reporting on professional baseball players who sustained LD or TM injuries was performed. Data were collected including patient presentation, injury management strategies, return-to-play (RTP) rates, time to RTP, patient-reported outcome measures, player performance after RTP, preinjury factors associated with injury, and complications. Results: Nine studies with 159 professional baseball players with a LD or TM injury were identified. All studies (2 retrospective cohort studies with high risk of bias and 7 case series) reported shoulder pain after pitching, and magnetic resonance imaging was performed in all cases to confirm diagnosis. Twenty-three patients underwent surgical treatment, whereas 136 patients underwent nonsurgical treatment. Overall RTP rates and performance between surgical and nonsurgical groups were similar (75% to 100% vs 75% to 93%), although the largest study reported improved performance with surgery. Two studies described a surgical technique with a posterior axillary approach and endosteal button fixation of the LD tendon. All studies reported a progressive strengthening and throwing program prior to returning to sport. Conclusion: Professional baseball players who suffer a LD or TM injury have predictable clinical presentations and imaging findings. There is a high RTP rate and performance with both surgical and nonsurgical management. The heterogeneity and low level of evidence of available literature precludes comparative conclusions between treatment approaches. Level of Evidence: IV systematic review of Level III and IV studies.

Outcomes of Distal Femoral Osteotomy for Valgus Malalignment: A Systematic Review and Meta-analysis of Closing Wedge Versus Opening Wedge Techniques.

BACKGROUND: Valgus knee deformity increases the risk for lateral articular chondral damage, contributing to earlier onset and accelerated progression of osteoarthritis. Distal femoral osteotomy (DFO) unloads the lateral joint compartment and can be performed using closing wedge (CW) or opening wedge (OW) techniques. PURPOSE: To perform a systematic review and meta-analysis for patients with valgus knee deformity undergoing DFO to determine differences in patient-reported outcome measures (PROMs), complications, and survival rates, comparing CW versus OW DFO. STUDY DESIGN: Systematic review, Level of evidence, 4. METHODS: A literature review was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines utilizing PubMed, Cochrane Database, Ovid/MEDLINE, and Scopus. Inclusion criteria consisted of studies reporting outcomes in patients undergoing CW or OW DFO for the treatment of valgus knee deformities with symptomatic lateral compartment pathology with a minimum 2-year follow-up. PROMs and complications were analyzed using random-effects modeling to identify differences in outcomes as a function of surgical technique. Long-term survival data, defined as conversion to total knee arthroplasty, were analyzed using a multiple metaregression model as a function of individual study follow-up time points and surgical technique. RESULTS: In total, we included 23 retrospective studies (n = 619 knees), of which 10 studies (n = 271 knees) reported outcomes after CW DFO and 13 studies (n = 348 knees) reported on OW DFO outcomes. Good to excellent clinical outcomes were reported in PROMs when compared with preoperative values with both techniques, while no significant differences between techniques were appreciated on functional Knee Society Scores and Tegner scores. No significant differences were appreciated in the incidence of complications reported in patients undergoing CW (20%) versus OW (33%) DFO (P = .432). Pain requiring hardware removal was the most commonly reported complication in both groups. The survival rate for CW DFO was 81.5% (mean follow-up, 8.8 ± 4.3 years) compared with 90.5% for OW DFO (mean follow-up, 4.5 ± 1.5 years). Multiple metaregression demonstrated that patient follow-up (P < .001) was significantly associated with knee survival, while surgical technique (P = .810) was not a predictor of clinical failure. CONCLUSIONS: Both CW and OW DFO techniques were associated with good to excellent clinical outcomes with no significant differences in PROMs based on technique. Pain requiring hardware removal was the most common complication in both techniques, while long-term survivability was found to be a function of follow-up and not surgical technique. Technique selection should be based on shared patient-physician decision making with an emphasis on surgeon preference and technique familiarity.

Travel distance does not affect outcomes after total shoulder arthroplasty.

Background: The purpose of this investigation was to determine the effect of travel distance on achieving the minimal clinically important difference (MCID) on all three commonly used patient-reported outcome measures (PROMs) for the shoulder more than 1 year following total shoulder arthroplasty (TSA). Methods: Patients undergoing reverse or anatomic TSA at a high-volume tertiary referral center between September 2016 and August 2018 were retrospectively reviewed. Patients were divided into 2 groups: driving distance of >50 miles from the location of surgery (referral group) and driving distance of <50 miles (local group). Scores on preoperative and postoperative PROMs, including American Shoulder and Elbow Surgeons (ASES) score, Single Assessment Numeric Evaluation (SANE) score, and Constant Score (CS) at minimum 1-year follow-up were assessed. Chi-square analysis was used to analyze the achievement of MCID on any PROM or a combination of PROMs. Logistic regression was performed to determine whether travel distance and other variables of interest had an effect on achieving MCID on all three PROMs. Results: A total of 214 patients with minimum 1-year follow-up were included in the final analysis. Of these, 165 patients (77.1%) traveled <50 miles to their orthopedic provider at the time of surgery. The local group demonstrated significantly inferior preoperative SANE scores (P < .001) and significantly higher postoperative ASES scores (P = .001). A total of 166 (77%) patients achieved all three MCIDs postoperatively. There was no significant difference between distance groups for achievement of all MCIDs (P = .328). On multivariable regression, body mass index > 30 (odds ratio [OR], 5.78; 95% confidence interval [CI], 1.53-30.28), worker's compensation status (OR, 16.78; 95% CI, 2.34-161.39), and higher preoperative ASES score (OR, 1.04; 95% CI, 1.01-1.07) were associated with an increased risk of failure to achieve all MCIDs (P < .05). Age, adjusted gross income, private insurance, and travel distance were not significantly associated with failure to achieve all MCIDs. Conclusions: After controlling for age, sex, and adjusted gross income, distance traveled to a high-volume referral center did not have an effect on achieving the MCID on all three commonly used PROMs for the shoulder at least 1 year after undergoing TSA. Elevated body mass index, worker's compensation status, and higher preoperative ASES score were associated with an increased risk of failure to achieve all MCIDs after TSA.

No Difference in Clinical Outcomes for Arthroscopic Suprapectoral Versus Open Subpectoral Biceps Tenodesis at Midterm Follow-up: A Randomized Prospective Analysis.

BACKGROUND: We have previously reported the 1-year outcomes of arthroscopic suprapectoral biceps tenodesis (ASPBT) versus open subpectoral biceps tenodesis (OSPBT) for the management of long head of the biceps tendon (LHBT) pathology. While patients had similar 1-year biceps muscle strength and pain, longer-term functional outcomes are unknown. PURPOSE: To directly compare clinical outcomes of ASPBT versus OSPBT with interference screw fixation, distal to the bony bicipital groove, at a minimum of 2 years' follow-up. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 85 patients undergoing biceps tenodesis (BT) for LHBT disease were randomized into the ASPBT or OSPBT group. Both techniques utilized polyether ether ketone inference screws for tenodesis fixation. Patients completed American Shoulder and Elbow Surgeons (ASES), Constant subjective, and Single Assessment Numeric Evaluation (SANE) questionnaires preoperatively and again at 6 months, 12 months, and at the final follow-up at a minimum of 24 months. RESULTS: A total of 73 patients (37/42 randomized to ASPBT [88%]; 36/42 randomized to OSPBT [86%]) with a mean age of 50.4 ± 10.3 years and a mean body mass index of 29 ± 7.9 were included in clinical outcome analyses. The mean final follow-up was 2.9 years (ASPBT, 3 years; OSPBT, 2.8 years [range 2-5.2 years]). Comparison of demographic characteristics and intraoperative findings showed no significant differences in age, sex, concomitant procedures, and rotator cuff disease. No statistically significant differences in the ASES (P = .25), Constant subjective (P = .52), and SANE scores (P = .61) were found at the final follow-up. Clinical outcomes scores showed no significant improvement from a mean of 12.6 months to the final follow-up at 34.5 months (ASPBT: ASES, P = .43; Constant, P = .25; SANE, P = .45 vs OSPBT: ASES, P = .65; Constant, P = .78; SANE, P = .70). No patients required revision of BT in either group. CONCLUSION: This study reported a minimum of 2-year follow-up of patients undergoing ASPBT or OSPBT, utilizing the same interference screw technique, for the management of LHBT pathology in the setting of concomitant shoulder procedures. There were no significant differences in patient-reported outcomes and complication rates found at any time point. REGISTRATION: NCT02192073 (ClinicalTrials.gov identifier).

Incidence of Injury for Professional Soccer Players in the United States: A 6-Year Prospective Study of Major League Soccer.

Background: Despite an abundance of injury research focusing on European professional soccer athletes, there are limited injury data on professional soccer players in the United States. Purpose: To describe the epidemiology of injury across multiple years in Major League Soccer (MLS) players. Study Design: Descriptive epidemiology study. Methods: A web-based health management platform was used to prospectively collect injury data from all MLS teams between 2014 and 2019. An injury was defined as an incident that required medical attention and was recorded into the health management platform anytime over the course of the 2014-2019 seasons. Injuries and exposure data were recorded in training and match settings to calculate injury incidence. Results: A total of 9713 injuries were recorded between 2014 and 2019. A mean 1.1 injuries per year per player were identified, with midfielders sustaining the largest number of injuries. The most common injuries were hamstring strains (12.3%), ankle sprains (8.5%), and adductor strains (7.6%). The mean time missed per injury was 15.8 days, with 44.2% of injuries resulting in no days missed. Overall injury incidence was 8.7 per 1000 hours of exposure, declining over the course of the investigation, with a 4.1-times greater mean incidence during matches (14.0/1000 h) than training (3.4/1000 h). Conclusion: Between 2014 and 2019, the most commonly reported injuries in MLS players were hamstring strains, ankle sprains, and adductor strains. Injury incidence during matches was 4.1 times greater when compared with training, while overall injury incidence was found to decline during the course of the study period.

Return to Play and Player Performance After Foot Fracture in UEFA Soccer Players.

Background: There is a paucity of information on rate and time to return to play (RTP) in elite-level soccer players who have sustained foot fractures. Purpose: To (1) determine the rate and timing of RTP after foot fracture (eg, tarsal, metatarsal, or phalangeal), (2) investigate foot fracture reinjury incidence after RTP, and (3) evaluate performance after foot fracture as compared with matched, uninjured controls. Study Design: Descriptive epidemiology study. Methods: Athletes sustaining foot fractures were identified across the 5 major European soccer leagues (English Premier League, Bundesliga, La Liga, Ligue 1, and Serie A) between 2000 and 2016. Injured athletes were matched to controls (1:1) using demographic characteristics and performance metrics from 1 season before injury. The authors recorded RTP rate, reinjury incidence, player characteristics associated with RTP within 2 seasons of injury, player availability, field time, and performance metrics during the 4 seasons after injury. Results: A total of 192 elite soccer players sustaining a foot fracture were identified; 40 players (20.8%) underwent operative treatment. Athletes missed an average of 69.41 ± 59.43 days and 5.15 ± 23.28 games. In the 4 seasons after injury, 80% of players returned to play, with 72% returning to play within 1 season of injury. Nine players (5%) sustained a subsequent foot fracture. Athletes with a foot fracture demonstrated significantly longer league retention compared with uninjured controls (P < .001). Elite soccer players older than 30 years of age were less likely to RTP (odds ratio, 0.67; P = .002), whereas career experience, field position, and baseline performance showed no significant association with RTP rates. Injured athletes demonstrated similar performance to controls during the 4 years after injury, and there were no position-dependent differences on subgroup analysis. The players who underwent operative treatment had more assists per 90 minutes and more team points per game during the first season after injury compared with athletes treated nonoperatively. Conclusion: Foot fractures in elite soccer players resulted in moderate loss of play time (69.41 days). RTP rates were high at 80%, although players older than 30 years of age were less likely to RTP. On RTP, athletes who sustained a foot fracture maintained performance similar to preinjury levels and to uninjured controls.

Return to Play and Player Performance After Meniscal Tear Among Elite-Level European Soccer Players: A Matched Cohort Analysis of Injuries From 2006 to 2016.

BACKGROUND: Meniscal injuries are extremely common in soccer athletes, and little is known about postrecovery performance. PURPOSE: To (1) identify characteristics associated with return to play (RTP) to the same league level and (2) evaluate long-term effects that injury and management approach may have on player performance. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Using publicly available records, we identified athletes who sustained meniscal tears across the 5 major European soccer leagues (English Premier League, Bundesliga, La Liga, Ligue 1, and Serie A) between 2006 and 2016. Injured athletes were matched to controls 1:2 by demographics and performance. Investigations included rate of RTP to the same league level, reinjury, player characteristics associated with RTP within 2 seasons, long-term availability, field time, and performance metrics standardized to 90 minutes of play during the next 4 seasons. RESULTS: A total of 250 players sustaining meniscal tears were included, of which 106 (42%) received surgical management. Median absence was 57.5 days (interquartile range [IQR], 35-92) or 7 games (IQR, 4-12). Rate of RTP was 70%, and the reinjury rate 5% if a player could RTP. Age greater than 30 years was a negative predictor for RTP (odds ratio [OR], 0.62; P = .002), whereas higher preinjury goals per game (OR, 2.80; P = .04) and surgical management (OR, 1.38; P = .002) were positive predictors for RTP. Surgical management was associated with higher long-term availability (P < .01). As compared with the control, there were no significant differences in field time or performance metrics after RTP, either overall or by player position. As compared with nonoperative management, defenders undergoing surgery demonstrated decreased field time. Attackers and midfielders demonstrated similar field time and performance regardless of management. CONCLUSION: RTP of elite soccer athletes sustaining meniscal tear is contingent on age, preinjury performance, and management approach. Those who RTP to the same league level can be expected to demonstrate equivalent field time, performance, and long-term availability as noninjured athletes.

Bone Marrow Aspirate Concentrate Augmentation May Accelerate Allograft Ligamentization in Anterior Cruciate Ligament Reconstruction: A Double-Blinded Randomized Controlled Trial.

PURPOSE: To assess the effect of bone marrow aspiration concentrate (BMAC) augmentation on clinical outcomes and magnetic resonance imaging (MRI) findings in anterior cruciate ligament (ACL) reconstruction (ACLR) with bone-patellar tendon-bone (BTB) allografts. METHODS: A double-blinded, randomized controlled trial was conducted on 80 patients undergoing ACL reconstruction using BTB allografts. Patients were randomized to 2 groups: (1) bone marrow aspirate was collected from the iliac crest, concentrated, and approximately 2.5 mL was injected into the BTB allograft, or (2) a small sham incision was made at the iliac crest (control). MRI was performed at 3 months and 9 months postoperatively to determine the signal intensity ratio of the ACL graft. RESULTS: Seventy-three patients were available for follow-up at 1-year postoperatively (36 BMAC, 37 control). International Knee Documentation Committee (IKDC) scores were significantly greater in the BMAC group versus the control at the 9-month postoperative period (81.6 ± 10.5 vs 74.6 ± 14.2, P = .048). There was no significant difference in the proportion of patients who met the minimal clinically important difference for IKDC between the BMAC and control groups at 9 months (89% vs 85%; P = .7). Three months postoperatively, signal intensity ratio of the inferior third of the ACL graft was significantly greater in the BMAC group versus the control group (3.2 ± 2.2 vs 2.1 ± 1.5; P = .02). CONCLUSIONS: Patients who received BMAC augmentation of the BTB allograft during ACL reconstruction demonstrated greater signal intensity scores on MRI at 3 months, suggesting increased metabolic activity and remodeling, and potentially accelerated ligamentization. Additionally, patients in the BMAC group had greater patient-reported outcomes (IKDC) at 9 months postoperatively when compared with those who underwent a standard surgical procedure. There was no significant difference in the proportion of patients who met the minimal clinically important difference for IKDC between the BMAC and control groups at 9 months, suggesting limited clinical significance at this time point. LEVEL OF EVIDENCE: I, randomized control trial.

Hybrid interpenetrating hydrogel network favoring the bidirectional migration of tenocytes for rotator cuff tendon regeneration.

Replenishment of tenocytes to the injury site is an ideal strategy to improve healing response and accelerate the tendon ECM regeneration. The present study focused on the synthesis and characterization of a hybrid hydrogel scaffold system poly(propylene-fumarate)-alginate-polyvinyl alcohol-acrylic acid (PAPA) using poly(propylene-fumarate) (PPF), alginate, polyvinyl alcohol (PVA) and acrylic acid and the in vitro investigation of bidirectional mobility of swine shoulder tenocytes (SST) for its potential application in rotator-cuff tendon regeneration. IR analysis revealed the presence of alginate, PPF and PVA segments on the surface, SEM and AFM analyses revealed the porous and nano-topographical features of PAPA, respectively, swelling was 712.6 ± 84.21% with the EWC (%) of 87.59 ± 1.26 having the diffusional exponent and swelling constant 0.551 and 1.8, respectively. PAPA was biodegradable, cytocompatible and supported long-term survival of SSTs. SEM imaging revealed the adhesion, colonization, and sheet formation of SSTs within the PAPA hydrogel network. The SSTs seeded on the PAPA scaffolds were peculiar for their bidirectional migration as the anterograde movement was completed in 9 days whereas the retrograde infiltration occurred up to the depth of 198 µm. These findings suggest the promising translational potential of PAPA scaffold system in the management of rotator cuff tendon injury.

The Role of RECK in Hepatobiliary Neoplasia Reveals Its Therapeutic Potential in NASH.

Non-alcoholic fatty liver disease (NAFLD) is a multimorbidity disorder ranging from excess accumulation of fat in the liver (steatosis) to steatohepatitis (NASH) and end-stage cirrhosis, and the development of hepatocellular carcinoma (HCC) in a subset of patients. The defining features of NASH are inflammation and progressive fibrosis. Currently, no pharmaceutical therapies are available for NAFLD, NASH and HCC; therefore, developing novel treatment strategies is desperately needed. Reversion Inducing Cysteine Rich Protein with Kazal motifs (RECK) is a well-known modifier of the extracellular matrix in hepatic remodeling and transition to HCC. More recently, its role in regulating inflammatory and fibrogenic processes has emerged. Here, we summarize the most relevant findings that extend our current understanding of RECK as a regulator of inflammation and fibrosis, and its induction as a potential strategy to blunt the development and progression of NASH and HCC.

Acromioclavicular Joint Separation in UEFA Soccer Players: A Matched-Cohort Analysis of Return to Play and Player Performance From 1999 to 2018.

BACKGROUND: Acromioclavicular joint (ACJ) separation injuries are uncommon in professional soccer players, threatening future performance and team contributions. Data regarding return to play (RTP) in professional soccer players after ACJ separation are limited. PURPOSE: To determine the rate, time to RTP, and player performance after ACJ separation in soccer players from the top 5 professional European leagues when compared with a retrospective, matched cohort of uninjured players. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Professional soccer players suffering ACJ separation injuries between 1999 and 2018 were identified and were matched to uninjured players (2 controls to 1 injured player) by position, height, age, season year, and length of time played. Information on date of injury, timing to RTP, and player performance metrics (minutes played, games played, goals scored, assists made, and points per game) were collected from transfermarkt.co.uk, uefa.com, fifa.com, official team websites, public injury reports, and press releases. Change in performance metrics for the 4 seasons after the season of injury were based on metrics 1 season before injury. Univariate comparisons were performed using independent 2-group t tests and Wilcoxon rank-sum tests when normality of distributions was violated. RESULTS: A total 59 soccer players with ACJ separation injuries were identified. Mean age at injury was 24.6 ± 5.3 years. Of these, 81% of the players returned to play, with 69% returning within postinjury season 1. Mean time to RTP was 49.8 ± 24.3 days (5.9 ± 4.1 games). Two players suffered recurrent ACJ separation injuries in their professional soccer careers. There were no significant differences between athletes who sustained ACJ injuries versus control athletes in the number of games played, minutes per game per season, goals scored, assists, or points in the 4 seasons after injury. Defenders played fewer minutes and recorded fewer assists during postinjury season 1 when compared with control athletes. CONCLUSION: Of the 59 elite soccer players who sustained ACJ separation injuries during the study period, 81% returned to elite competition. Performance metrics were similar to preinjury levels and matched, uninjured control players.

Return-to-Play Times and Player Performance After Medial Collateral Ligament Injury in Elite-Level European Soccer Players.

BACKGROUND: Participation in elite-level soccer predisposes athletes to injuries of the medial collateral ligament (MCL), resulting in variable durations of time lost from sport. PURPOSE: To (1) determine the rate of return to play (RTP) and timing after MCL injuries, (2) investigate MCL reinjury incidence after RTP, and (3) evaluate the long-term effects of MCL injury on future performance. STUDY DESIGN: Descriptive epidemiology study. METHODS: Using publicly available records, we identified athletes who had sustained MCL injury between 2000 and 2016 across the 5 major European soccer leagues (English Premier League, Bundesliga, La Liga, Ligue 1, and Serie A). Injured athletes were matched to controls using demographic characteristics and performance metrics from the season before injury. We recorded injury severity, RTP rate, reinjury incidence, player characteristics associated with RTP within 2 seasons of injury, player availability, field time, and performance metrics during the 4 seasons after injury. RESULTS: A total of 59 athletes sustained 61 MCL injuries, with 86% (51/59) of injuries classified as moderate to severe and surgical intervention performed in 14% (8/59) of athletes. After injury, athletes missed a median of 33 days (range, 3-259 days) and 4 games (range, 1-30 games). Overall, 71% (42/59) of athletes returned successfully at the same level, with multivariable regression demonstrating no athlete characteristic predictive of RTP. MCL reinjury was reported in 3% (2/59) of athletes. Midfielders demonstrated decreased field time after RTP when compared with controls (P < .05). No significant differences in player performance for any position were identified out to 4 seasons after injury. Injured athletes had a significantly higher rate of long-term retention (P < .001). CONCLUSION: MCL injuries resulted in a median loss of 33 days in elite European soccer athletes, with the majority of injuries treated nonoperatively. RTP remained high, and few athletes experienced reinjury. While midfielders demonstrated a significant decrease in field time after RTP, player performance and long-term retention were not compromised. Future studies are warranted to better understand athlete-specific and external variables predictive of MCL injury and reinjury, while evaluating treatment and rehabilitation protocols to minimize time lost and to optimize athlete safety and health.

Fabella Syndrome and Common Peroneal Neuropathy following Total Knee Arthroplasty.

CASE: A 62-year-old man presented with persistent lateral knee pain 15 months following an uncomplicated total knee arthroplasty. There was a tendinous snapping structure over the lateral aspect of the knee in deep flexion with positive Tinel's sign over the fibular head. The patient underwent an uncomplicated flabella excision. The patient was cleared to return to work and full duty at two months postoperatively. CONCLUSION: Flabella syndrome is a rare but increasingly common mechanism of persistent lateral knee pain following total knee arthroplasty. Surgeons should be aware of this etiology of persistent lateral knee pain and offer treatment modalities to address this pathology.

Avulsion Injuries and Ruptures of the Proximal Rectus Femoris in Skeletally Mature, High-Level Athletes: A Critical Analysis Review.

¼: Injuries to the proximal rectus femoris remain rare, occurring primarily in soccer and American football athletes during kicking and sprinting because of its unique biarthrodial nature. ¼: The appropriate diagnosis is dependent on careful physical examination and imaging interpretation. ¼: While no universal treatment algorithm has been adopted for high-level athletes, recent investigations support operative repair using suture anchors to restore strength and function in order to allow an effective return to competition while minimizing the risk of injury recurrence. ¼: Complications following surgical management include injury to the lateral femoral cutaneous nerve and hematoma formation, and there are reports of residual pain and weakness with chronic injuries that fail the initial nonoperative treatment. ¼: Current investigations examining outcomes following treatment remain limited, warranting additional studies that examine patient-reported results, return-to-play rates, and the role of orthobiologics and accelerated rehabilitation protocols following injury to further improve athlete health and safety.

Return-to-Play Times and Player Performance After ACL Reconstruction in Elite UEFA Professional Soccer Players: A Matched-Cohort Analysis From 1999 to 2019.

BACKGROUND: Anterior cruciate ligament (ACL) rupture is one of the most common injuries afflicting soccer players and requires a lengthy recovery processes after reconstructive surgery. The impact of ACL reconstruction (ACLR) on return to play (RTP) time and player performance in professional soccer players remains poorly studied. PURPOSE/HYPOTHESIS: To determine player performance and RTP rate and time after ACLR in elite professional soccer players with a retrospective matched-cohort analysis. We expected that the RTP time and rate will be similar to those of other professional-level athletes. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Included were 51 players from 1 of the 5 elite Union of European Football Associations (UEFA) soccer leagues who suffered a complete ACL rupture between 1999 and 2019. These athletes were matched by position, age, season of injury, seasons played, and height and compared to uninjured control players. Change in performance metrics for the 4 years after the season of injury were compared with metrics 1 season before injury. Univariate 2-group comparisons were performed using independent 2-group t tests; Wilcoxon rank-sum tests were used when normality of distributions was violated. RESULTS: Overall, 41 players (80%) returned to play after ACL rupture, with 6 (12%) experiencing a subsequent ipsilateral or contralateral ACL tear. The mean (±SD) RTP time for soccer players after ACLR was 216 ± 109 days (26 ± 18 games). Injured athletes played significantly fewer games and minutes per season and recorded inferior performances for 2 seasons after their injury (P < .001). However, the game performance of injured players equaled or exceeded that of their matched controls by season 3 after injury, with the exception of attackers, who demonstrated a continued decline in performance (P < .001). CONCLUSION: Results indicated that the mean RTP time for soccer players after ACLR is short in comparison with other major sports leagues (216 days). However, RTP rates were high, and rerupture rates were comparable with those of other sports. With the exception of attackers, player performance largely equaled or exceeded that of matched controls by the third postinjury season.

Return to Play and Player Performance After Achilles Tendon Rupture in UEFA Professional Soccer Players: A Matched-Cohort Analysis of Players From 1999 to 2018.

BACKGROUND: Achilles tendon rupture (ATR) is a potentially career-ending injury in professional athletes. Limited information exists regarding return to play (RTP) in professional soccer players after this injury. PURPOSE: To determine the RTP rate and time in professional soccer players after ATR and to evaluate player performance relative to matched controls. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: We evaluated 132 professional soccer players who suffered an ATR between 1999 and 2018. These athletes were matched 2:1 to uninjured controls by position, age, season of injury, seasons played, and height. We collected information on the date of injury, the date of RTP, and player performance metrics (minutes played, games played, goals scored, assists made, and points per game) from official team websites, public injury reports, and press releases. Changes in performance metrics for the 4 years after the season of injury were compared with metrics 1 season before injury. Univariate comparisons were performed using independent-sample, 2-group t tests and Wilcoxon rank-sum tests when normality of distributions was violated. RESULTS: The mean age at ATR was 27.49 ± 4.06 years, and the mean time to RTP was 5.07 ± 2.61 months (18.19 ± 10.96 games). The RTP rate was 71% for the season after injury and 78% for return at any timepoint. Overall, 9% of the injured players experienced a rerupture during the study period. Compared with controls, the injured players played significantly less (-6.77 vs -1.81 games [P < .001] and -560.17 vs -171.17 minutes [P < .05]) and recorded fewer goals (-1.06 vs -0.29 [P < .05]) and assists (-0.76 vs -0.02 [P < .05]) during the season of their Achilles rupture. With the exception of midfielders, there were no significant differences in play time or performance metrics between injured and uninjured players at any postinjury timepoint. CONCLUSION: Soccer players who suffered an ATR had a 78% RTP rate, with a mean RTP time of 5 months. Injured players played less and demonstrated inferior performance during the season of injury. With the exception of midfielders, players displayed no significant differences in play time or performance during any of the 4 postinjury seasons.

Matrix regeneration proteins in the hypoxia-triggered exosomes of shoulder tenocytes and adipose-derived mesenchymal stem cells.

Regenerative functions of exosomes rely on their contents which are influenced by pathological stimuli, including hypoxia, in rotator cuff tendon injuries (RCTI). The hypoxic environment triggers tenocytes and adjacent adipose-derived mesenchymal stem cells (ADMSCs) to release regenerative mediators to the ECM via the exosomes which elicit autocrine/paracrine responses to protect the tendon matrix from injury. We investigated the exosomal protein contents from tenocytes and subcutaneous ADMSCs from the shoulder of Yucatan microswine cultured under hypoxic conditions (2% O2). The exosomal proteins were detected using high-resolution mass spectrometry nano-LC-MS/MS Tribrid system and were compiled using 'Scaffold' software. Hypoxic exosomes from tenocytes and ADMSCs carried 199 and 65 proteins, respectively. The key proteins identified by mass spectrometry and associated with ECM homeostasis from hypoxic ADMSCs included MMP2, COL6A, CTSD and TN-C and those from hypoxic tenocytes were THSB1, NSEP1, ITIH4 and TN-C. These findings were confirmed at the mRNA and protein level in the hypoxic ADMSCs and tenocytes. These proteins are involved in multiple signaling pathways of ECM repair/regeneration. This warrants further investigations for their translational significance in the management of RCTI.