Experts Achieve Consensus on a Majority of Statements Regarding Platelet-Rich Plasma Treatments for Treatment of Musculoskeletal Pathology.

PURPOSE: To establish consensus statements on platelet-rich plasma (PRP) for the treatment of musculoskeletal pathologies. METHODS: A consensus process on the treatment of PRP using a modified Delphi technique was conducted. Thirty-five orthopaedic surgeons and sports medicine physicians participated in these consensus statements on PRP. The participants were composed of representatives of the Biologic Association, representing 9 international orthopaedic and musculoskeletal professional societies invited due to their active interest in the study of orthobiologics. Consensus was defined as achieving 80% to 89% agreement, strong consensus was defined as 90% to 99% agreement, and unanimous consensus was indicated by 100% agreement with a proposed statement. RESULTS: There was consensus on 62% of statements about PRP. CONCLUSIONS: (1) PRP should be classified based on platelet count, leukocyte count, red blood count, activation method, and pure-plasma versus fibrin matrix; (2) PRP characteristics for reporting in research studies are platelet count, leukocyte count, neutrophil count, red blood cell count, total volume, the volume of injection, delivery method, and the number of injections; (3) the prognostic factors for those undergoing PRP injections are age, body mass index, severity/grade of pathology, chronicity of pathology, prior injections and response, primary diagnosis (primary vs postsurgery vs post-trauma vs psoriatic), comorbidities, and smoking; (4) regarding age and body mass index, there is no minimum or maximum, but clinical judgment should be used at extremes of either; (5) the ideal dose of PRP is undetermined; and (6) the minimal volume required is unclear and may depend on the pathology. LEVEL OF EVIDENCE: Level V, expert opinion.

An Initial Injection and a Crossover Injection of Amniotic Suspension Allograft Following Failed Treatment with Hyaluronic Acid or Saline Are Equally Effective in the Treatment of Moderate Symptomatic Knee Osteoarthritis Over 12 Months.

PURPOSE: The purpose of this crossover study was to determine the efficacy of amniotic suspension allograft (ASA) for moderate symptomatic knee osteoarthritis following failed treatment with hyaluronic acid (HA) or saline through 12 months' postcrossover injection using patient-reported and safety outcomes. METHODS: In this multicenter study, 95 patients from a 200-patient single-blind randomized controlled trial were eligible to crossover and receive a single injection of ASA 3 months after failed treatment with HA or saline. Patient-reported outcomes, including Knee Injury and Osteoarthritis Outcome Score (KOOS) and visual analog scale (VAS), were collected out to 12 months postcrossover to determine pain and function. Radiographs and blood were collected for assessment of changes. Statistical analyses were performed using mixed effects model for repeated measures. RESULTS: Treatment with ASA following failed treatment with HA or saline resulted in significant improvements in KOOS and VAS scores compared with crossover baseline. There were no differences in radiographic measures or anti-human leukocyte antigen serum levels compared with baseline and no severe adverse events reported. In addition, more than 55% of patients were responders at months 3, 6, and 12 as measured by the Outcome Measures in Arthritis Clinical Trials-Osteoarthritis Research Society International simplified responder criteria. There were no significant differences between the original ASA randomized group and crossover cohorts at any of the time points evaluated, suggesting that prior failed treatment with HA or saline did not significantly impact outcomes following treatment with ASA. CONCLUSIONS: This study showed that patients who previously failed treatment with HA or saline had statistically significant improvements in pain and function scores following a crossover injection of ASA that was sustained for 12 months, as measured by KOOS and VAS. There were no serious adverse events reported, and the injection was safe. LEVEL OF EVIDENCE: II, prospective cohort study.

Editorial Commentary: When Treating Cartilage Lesions With Osseous Involvement, Biologic "Chondrofacilitation" Using Either Bone Marrow Aspirate Concentrate or Mesenchymal Stem Cells Augments Microfracture.

The use of biologic augmentation following microfracture for symptomatic cartilage defects of the knee with osseous involvement shows encouraging results. Bone marrow aspirate concentrate provides growth factors to the injury site, such as vascular endothelial growth factor, platelet-derived growth factor, transforming growth factor-ßa, and bone morphogenetic proteins in addition to the mesenchymal stem cells present in the concentrate. Cellular-based therapies like mesenchymal stem cells are becoming more widely used in conjunction with surgical treatment of focal cartilage lesions with early promising results. Both treatment options improve clinical and radiographic outcomes. As for the efficacy of mesenchymal stem cells versus bone marrow aspirate concentrate, we believe that both have promising results.

Complications Following Biologic Therapeutic Injections: A Multicenter Case Series.

PURPOSE: To describe the complications that occur following biologic therapeutic injections. METHODS: We queried physician members of the Biologic Association, a multidisciplinary organization dedicated to providing a unified voice for all matters related to musculoskeletal biologics and regenerative medicine. Patients included in this study must have (1) received a biologic injection, (2) sustained an adverse reaction, and (3) had a minimum of 1-year follow-up after the injection. Patient demographic information, medical comorbidities, diagnoses, and previous treatments were recorded. The type of injection, injection setting, injection manufacturers, and specific details about the complication and outcome were collected. RESULTS: In total, 14 patients were identified across 6 institutions in the United States (mean age 63 years, range: 36-83 years). The most common injections in this series were intra-articular knee injections (50%), followed intra-articular shoulder injections (21.4%). The most common underlying diagnosis was osteoarthritis (78.5%). Types of injections included umbilical cord blood, platelet-rich plasma, bone marrow aspirate concentrate, placental tissue, and unspecified "stem cell" injections. Complications included infection (50%), suspected sterile inflammatory response (42.9%), and a combination of both (7.1%). The most common pathogen identified from infection cases was Escherichia coli (n = 4). All patients who had isolated infections underwent treatment with at least one subsequent surgical intervention (mean: 3.6, range: 1-12) and intravenous antibiotic therapy. CONCLUSIONS: This study demonstrates that serious complications can occur following treatment with biologic injections, including infections requiring multiple surgical procedures and inflammatory reactions. LEVEL OF EVIDENCE: Level IV, case series.

Safety and Efficacy of an Amniotic Suspension Allograft Injection Over 12 Months in a Single-Blinded, Randomized Controlled Trial for Symptomatic Osteoarthritis of the Knee.

PURPOSE: The purpose of this study is to determine the efficacy of amniotic suspension allograft (ASA) compared to hyaluronic acid (HA) and saline at up to 12 months of follow-up through the use of patient-reported outcomes, immunoglobulin levels, and anti-human leukocyte antigen (HLA) levels. METHODS: Within this multicenter study, 200 patients were randomized 1:1:1 to a single intra-articular injection of saline, HA, or ASA. Patient-reported outcomes, including Knee Injury and Osteoarthritis Outcome Score (KOOS) and visual analog scale (VAS) score, were collected at multiple time points (baseline, 1 week, 6 weeks, 3 months, 6 months) out to 12 months to assess improvements in pain and function. Radiographs at baseline and 12 months were taken to determine radiographic changes, while blood was collected at baseline, 6 weeks, and 6 months to determine changes in immunoglobulins and anti-HLA levels. Statistical analyses were performed using last observation carried forward and mixed effects model for repeated measures. RESULTS: Treatment with ASA resulted in significant improvements in KOOS and VAS scores that were maintained through 12 months (P < .05). Treatment with ASA resulted in a 63.2% responder rate at 12 months using the Outcome Measures in Arthritis Clinical Trials-Osteoarthritis Research Society International simplified definition. There were no significant differences between groups for radiographic measures in the index knee, immunoglobulins, C-reactive protein, or anti-HLA serum levels (P > .05). The number and type of adverse events (AEs) reported for ASA were comparable to the HA injection group, while no treatment-emergent AEs were reported for the saline group. CONCLUSIONS: This randomized controlled trial of ASA vs HA and saline for the treatment of symptomatic knee osteoarthritis demonstrated clinically meaningful improved outcomes with ASA over the controls out to 12 months postinjection. No concerning immunologic or adverse reactions to the ASA injection were identified with regards to severe AEs, immunoglobulin, or anti-HLA levels. LEVEL OF EVIDENCE: Level I, randomized controlled multicenter trial.

Assessing the Resident Progenitor Cell Population and the Vascularity of the Adult Human Meniscus.

PURPOSE: To identify, characterize, and compare the resident progenitor cell populations within the red-red, red-white, and white-white (WW) zones of freshly harvested human cadaver menisci and to characterize the vascularity of human menisci using immunofluorescence and 3-dimensional (3D) imaging. METHODS: Fresh adult human menisci were harvested from healthy donors. Menisci were enzymatically digested, mononuclear cells isolated, and characterized using flow cytometry with antibodies against mesenchymal stem cell surface markers (CD105, CD90, CD44, and CD29). Cells were expanded in culture, characterized, and compared with bone marrow-derived mesenchymal stem cells. Trilineage differentiation potential of cultured cells was determined. Vasculature of menisci was mapped in 3D using a modified uDisco clearing and immunofluorescence against vascular markers CD31, lectin, and alpha smooth muscle actin. RESULTS: There were no significant differences in the clonogenicity of isolated cells between the 3 zones. Flow cytometry showed presence of CD44+CD105+CD29+CD90+ cells in all 3 zones with high prevalence in the WW zone. Progenitors from all zones were found to be potent to differentiate to mesenchymal lineages. Larger vessels in the red-red zone of meniscus were observed spanning toward red-white, sprouting to smaller arterioles and venules. CD31+ cells were identified in all zones using the 3D imaging and co-localization of additional markers of vasculature (lectin and alpha smooth muscle actin) was observed. CONCLUSIONS: The presence of resident mesenchymal progenitors was evident in all 3 meniscal zones of healthy adult donors without injury. In addition, our results demonstrate the presence of vascularization in the WW zone. CLINICAL RELEVANCE: The existence of progenitors and presence of microvasculature in the WW zone of the meniscus suggests the potential for repair and biologic augmentation strategies in that zone of the meniscus in young healthy adults. Further research is necessary to fully define the functionality of the meniscal blood supply and its implications for repair.

How to Address the Medial Patellofemoral Ligament, Tibial Tubercle, and Articular Cartilage in Patients With Recurrent Patellar Instability.

Patellofemoral instability is a common pathology especially in the adolescent female population.1,2 Prompt diagnosis and management is critical to prevent future episodes of instability as well as to reduce the risk of cartilaginous injury to the patellofemoral articular surface. Initial management of a first-time patellar dislocation has historically been nonsurgical; however, the presence of intra-articular loose bodies or osseocartilaginous injury may require surgical intervention.3,4 More recent evidence has shown patients with specific risk factors such as skeletal immaturity, an incompetent medial soft-tissue sleeve, family history of patellar dislocation, elevated tibial tubercle to trochlear groove distance, patella alta, and high-grade trochlear dysplasia experience high rates of re-dislocation after initial nonsurgical management.4-9 Based on this, the provider needs to consider these risk factors and the possibility of initial surgical management in these patient populations following a first-time patellar dislocation. Surgical options for management of patellar instability and cartilaginous injury include medial patellofemoral ligament repair, medial patellofemoral ligament reconstruction, tibial tubercle osteotomy, and various cartilaginous repair/restoration procedures. It is important to be knowledgeable about the clinical and anatomic/radiographic risk factors associated with patients presenting with patellar instability, the algorithm for treatment, the indications and surgical technique for medial patellofemoral ligament reconstruction and tibial tubercle osteotomy, and management of cartilaginous injury to the patellofemoral joint.

Editorial Commentary: Anterior Cruciate Ligament Injury and Reconstruction in Soccer Players: The Major Challenge Is Always Going for Our Goals!

Anterior cruciate ligament (ACL) injury affects a large number of athletes worldwide, and long-term rate of return to soccer is approximately 50% or less. ACL injury, which is noncontact in approximately 90% of cases, has a complex multifactorial etiology. Younger and higher-level players do better, and 10-year outcomes are superior to baseline. The role of genomics, hormonal status, neuromuscular deficiencies, anatomy, and the environment are all potential contributory risk factors that vary with respect to the individual, especially the female athlete. Furthermore, ACL injury results in a local and regional catabolic cascade and cytokine release, creating an intra-articular environment that is a homeostatic perfect storm and spectrum of scalable articular cartilage and meniscal injury. Once these complexities in the knee organ are defined and understood, the surgeon's early objectives are stabilization, repair, and restoration with full harmonization of biomechanics, neuromuscular control, and homeostasis. The goal is optimizing long-term outcomes, decreasing the rate of subsequent ACL injury, and preventing osteoarthritis.

Degenerative Meniscus Lesions: An Expert Consensus Statement Using the Modified Delphi Technique.

PURPOSE: The purpose of this study was to perform an evidence-based, expert consensus survey using the Delphi panel methodology to develop recommendations for the treatment of degenerative meniscus tears. METHODS: Twenty panel members were asked to respond to 10 open-ended questions in rounds 1 and 2. The results of the first 2 rounds served to develop a Likert-style questionnaire for round 3. In round 4, the panel members outside consensus were contacted and asked to either change their score in view of the group's response or argue their case. The level of agreement for round 4 was defined as 80%. RESULTS: There was 100% agreement on the following items: insidious onset, physiological part of aging, tears often multiplanar, not all tears cause symptoms, outcomes depend on degree of osteoarthritis, obesity is a predictor of poor outcome, and younger patients (<50 years) have better outcomes. There was between 90% and 100% agreement on the following items: tears are nontraumatic, radiographs should be weightbearing, initial treatment should be conservative, platelet-rich plasma is not a good option, repairable and peripheral tears should be repaired, microfracture is not a good option for chondral defects, the majority of patients obtain significant improvement and decrease in pain with surgery but results are variable, short-term symptoms have better outcomes, and malalignment and root tears have poor outcomes. CONCLUSIONS: This consensus statement agreed that degenerative meniscus tears are a normal part of aging. Not all tears cause symptoms and, when symptomatic, they should initially be treated nonoperatively. Repairable tears should be repaired. The outcome of arthroscopic partial meniscectomy depends on the degree of osteoarthritis, the character of the meniscus lesion, the degree of loss of joint space, the amount of malalignment, and obesity. The majority of patients had significant improvement, but younger patients and patients with short-term symptoms have better outcomes. LEVEL OF EVIDENCE: Level V - expert opinion.

Editorial Commentary: Platelet-Rich Plasma Details Are Critical to Outcome Catching Is Always Better Than Fishing.

The use of platelet-rich plasma (PRP) and the spectrum of orthobiological interventions has been a major innovation in orthopedic surgery and medicine. Biological-based therapies for musculoskeletal disorders and injuries have gained popularity in the past decade and created significant expectation as the future of sports medicine, based on theoretical advantages including minimal invasiveness, greater healing potential, faster recovery, and a less expensive alternative to surgery. These therapies for musculoskeletal intervention include PRP, bone marrow aspirate concentrate, cellular-based therapies, and tissue engineering. Surgeons must always identify and respect the gap between hope, knowledge, and evidence to be successful and efficient in the care of patients. Age, body mass index, and dietary factors may have significant impact on the performance of PRP as a therapeutic intervention. It is imperative that the clinician be armed with a meticulous, comprehensive, and refined technique, protocol, and algorithm to be successful in the use of the PRP.

How to Manage Cartilage Injuries?

Although small cartilage injuries are commonly found in knee arthroscopy procedures, significant chondral and osteochondral injuries are relatively infrequent. Incidence of cartilage injury rises when considering traumatic origin, especially when approaching significant ligamentous or meniscal pathology. Options for restoration span the gamut from benign neglect to open procedures that restore both cartilage and subchondral bone. The best choice of procedure largely depends on lesion size, depth, and location. Smaller lesions isolated to cartilage <2 cm2 can be treated with marrow stimulation techniques such as microfracture with or without biologic options (bone marrow aspirate concentrate or platelet-rich plasma with or without cartilage precursors or scaffolds). Microfracture alone in larger lesions has been reported to be less durable and it is therefore not recommended for larger lesions. Smaller lesions <2 cm2 that include a subchondral injury can be treated with osteochondral autograft implantation, in which a core of cartilage and bone is transferred from a relative non-weightbearing surface to the lesion. Larger osteochondral lesions >2 cm2 are better treated with osteochondral allograft transplantation, where osteochondral cores from a size-matched, fresh cadaver are matched to the patient's lesion. This option may require multiple cores to be placed in a "snowman" pattern; however, recent literature demonstrated that a single plug might produce better outcomes. Alternatively, for large chondral-only lesions, a resurfacing procedure may be chosen that may include biologic options. Autologous chondrocyte implantation (ACI), currently in its third iteration (matrix ACI [MACI]), is an excellent choice with good long-term durability. In addition, MACI may be used for chondral lesions in the patellofemoral joint where matching the native joint topology may be more difficult. If the patient has an underlying bone marrow lesion but an intact cartilage cap that appears healthy on arthroscopic examination, one may consider a core decompression and injection with biologics such as BMAC and bony scaffold with fibrin glue (also known as bioplasty). It is also critical that the surgeon address any concomitant knee pathology that would compromise cartilage restoration. This includes addressing malalignment with distal femoral, proximal tibial, or tibial tubercle osteotomy, significant meniscal deficiency with meniscal transplant, and any instability from lack of cruciate or collateral ligaments with ligament reconstruction.

Editorial Commentary: Second-Generation Microfracture-We Are Only As Strong As Our Weakest Link.

Injuries to the articular cartilage of the knee are increasingly common, especially in athletes. The operative management of these focal chondral lesions continues to be a regenerative challenge. The microfracture (MFx) procedure has become a first-line arthroscopic treatment method for small, symptomatic chondral lesions, and it frequently serves as the standard technique against which other cartilage repair procedures are compared. Over time, outcome studies have defined the weaknesses and limitations of first-generation MFx. The second iteration of MFx seeks to optimize regeneration using the trilogy of cells, scaffolds, and growth factors. As surgeons, we are only as strong as our weakest link.

Biological Treatment for Osteoarthritis of the Knee: Moving from Bench to Bedside-Current Practical Concepts.

Biological-based therapies for cartilage pathology have gained considerable recognition in the last few decades due to their potential benefits including their minimal invasiveness, capacity for unprecedented healing, and potential for rapid recovery. Consequently, these therapies are likely to have the most noteworthy impact on patients with degenerative joint changes who want to remain active. Currently, the most researched treatments include platelet-rich plasma (PRP), bone marrow aspirate concentrate (BMAC), and cell-based therapies. Although further basic science research and well-designed randomized clinical trials are needed to elucidate the long-term role of these therapies in the treatment of osteoarthritis, there is compelling evidence for their use for certain indications. This article aims to review the existing literature for biological-based treatment options for osteoarthritis, critically assessing the current evidence-based recommendations and identify potential avenues for development.

Clinical Outcomes After Arthroscopic Release of Patellofemoral Arthrofibrosis in Patients With Prior Anterior Cruciate Ligament Reconstruction.

PURPOSE: The purpose of this study was to review our results of arthroscopic release in patients diagnosed with refractory patellofemoral arthrofibrosis (PFA) after having undergone anterior cruciate ligament (ACL) reconstruction. METHODS: From 2006 to 2016, all patients who underwent arthroscopic release for refractory PFA after ACL reconstruction were reviewed retrospectively. All patients then completed surveys containing the International Knee Documentation Committee (IKDC) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and were asked 2 subjective questions. Patients included in the study exhibited at least one finding of PFA and failed conservative treatment for at least 3 months. Included patients also had a minimum of 12 months of postoperative follow-up after PFA release. Patients who underwent any other concomitant surgery in the same operative setting as arthroscopic release for PFA were excluded from the study. RESULTS: Thirty-two patients were included in the study. The mean age was 32.8 years (range, 19-58 years) with an average follow-up of 43.6 months (range, 16-98 months). There was a statistically significant increase preoperatively to postoperatively in the IKDC score from 49.6 to 69.4 (P < .00001), and 16 of 32 patients (50%) achieved a minimal clinically important difference (MCID). WOMAC scores also significantly increased from 74 to 85.3 (P < .00001), with 15 of 32 patients (47%) achieving MCID. Thirty-one patients (97%) reported that the procedure helped, and 25 patients (78%) said they would have the procedure again. CONCLUSIONS: Arthroscopic release, consisting of an extended lateral release, debridement of the notch/fat pad, and manual manipulation of the patella, results in significant increases in validated outcome measures and is well tolerated by patients. LEVEL OF EVIDENCE: Level IV, case series.

Higher compliance to a neuromuscular injury prevention program improves overall injury rate in male football players.

PURPOSE: The 11+ injury prevention program has been shown to decrease injury rate. However, few studies have investigated compliance and if it is correlated to time loss. The purpose of this study was to (1) analyze how differences in compliance may impact injury rate and (2) if compliance may impact time loss due to injury. METHODS: This study was a Level 1 prospective cluster randomized controlled trial conducted in NCAA men's football (soccer) teams that examined the efficacy of the 11+ injury prevention program. The two outcome variables examined were number of injuries and number of days missed from competition. Twenty-seven teams (n = 675 players) used the 11+ program. Compliance, injuries and time loss were recorded. There were three compliance categories, low (LC, 1-19 doses/season), moderate (MC, 20-39 doses/season), and high (HC, > 40 doses/season). RESULTS: There was a significant difference among the groups for injuries, p = 0.04, pη2 = 0.23. The LC group [mean (M) = 13.25, 95% confidence interval (CI) 9.82-16.68, injury rate (IR) = 10.35 ± 2.21] had a significantly higher injury rate than the HC group (M = 8.33, 95%CI 6.05-10.62, IR = 10.35 ± 2.21), p = 0.02. The MC group (M = 11.21, 95%CI 9.38-13.05, IR = 8.55 ± 2.46) was not significantly different than the LC group, p = 0.29, but was significantly greater than the HC group, p = 0.05. When examined as a continuous variable, compliance was significantly negatively related to injury rate (p = 0.004). It was also significantly negatively related to number of days missed (p = 0.012). CONCLUSIONS: When compliance was high, there was a significant reduction in injury and time loss. This evidence reinforces the importance of consistent injury prevention program utilization. Clinically, these findings have important implications when discussing the importance of consistent utilization of an injury prevention protocol in sport. LEVEL OF EVIDENCE: Level 1-Randomized controlled trial (RCT).

Does the FIFA 11+ Injury Prevention Program Reduce the Incidence of ACL Injury in Male Soccer Players?

BACKGROUND: The FIFA 11+ injury prevention program has been shown to decrease the risk of soccer injuries in men and women. The program has also been shown to decrease time loss resulting from injury. However, previous studies have not specifically investigated how the program might impact the rate of anterior cruciate ligament (ACL) injury in male soccer players. QUESTIONS/PURPOSES: The purpose of this study was to examine if the FIFA 11+ injury prevention program can (1) reduce the overall number of ACL injuries in men who play competitive college soccer and whether any potential reduction in rate of ACL injuries differed based on (2) game versus practice setting; (3) player position; (4) level of play (Division I or II); or (5) field type. METHODS: This study was a prospective cluster randomized controlled trial, which was conducted in 61 Division I and Division II National Collegiate Athletic Association men's soccer teams over the course of one competitive soccer season. The FIFA 11+ is a 15- to 20-minute on-the-field dynamic warm-up program used before training and games and was utilized as the intervention throughout the entire competitive season. Sixty-five teams were randomized: 34 to the control group (850 players) and 31 to the intervention group (675 players). Four intervention teams did not complete the study and did not submit their data, noting insufficient time to complete the program, reducing the number for per-protocol analysis to 61. Compliance to the FIFA 11+ program, athletic exposures, specific injuries, ACL injuries, and time loss resulting from injury were collected and recorded using a secure Internet-based system. At the end of the season, the data in the injury surveillance system were crosshatched with each individual institution's internal database. At that time, the certified athletic trainer signed off on the injury collection data to confirm their accuracy and completeness. RESULTS: A lower proportion of athletes in the intervention group experienced knee injuries (25% [34 of 136]) compared with the control group (75% [102 of 136]; relative risk [RR], 0.42; 95% confidence interval [CI], 0.29-0.61; p < 0.001). When the data were stratified for ACL injury, fewer ACL injuries were reported in the intervention group (16% [three of 19]) compared with the control group (84% [16 of 19]), accounting for a 4.25-fold reduction in the likelihood of incurring ACL injury (RR, 0.236; 95% CI, 0.193-0.93; number needed to treat = 70; p < 0.001). With the numbers available, there was no difference between the ACL injury rate within the FIFA 11+ group and the control group with respect to game and practice sessions (games-intervention: 1.055% [three of 15] versus control: 1.80% [12 of 15]; RR, 0.31; 95% CI, 0.09-1.11; p = 0.073 and practices-intervention: 0% [zero of four] versus control: 0.60% [four of four]; RR, 0.14; 95% CI, 0.01-2.59; p = 0.186). With the data that were available, there were no differences in incidence rate (IR) or injury by player position for forwards (IR control = 0.339 versus IR intervention = 0), midfielders (IR control = 0.54 versus IR intervention = 0.227), defenders (IR control = 0.339 versus IR intervention = 0.085), and goalkeepers (IR control = 0.0 versus IR intervention = 0.0) (p = 0.327). There were no differences in the number of ACL injuries for the Division I intervention group (0.70% [two of nine]) compared with the control group (1.05% [seven of nine]; RR, 0.30; CI, 0.06-1.45; p = 0.136). However, there were fewer ACL injuries incurred in the Division II intervention group (0.35% [one of 10]) compared with the control group (1.35% [nine of 10]; RR, 0.12; CI, 0.02-0.93; p = 0.042). There was no difference between the number of ACL injuries in the control group versus in the intervention group that occurred on grass versus turf (Wald chi square [1] = 0.473, b = 0.147, SE = 0.21, p = 0.492). However, there were more ACL injuries that occurred on artificial turf identified in the control group (1.35% [nine of 10]) versus the intervention group (0.35% [one of 10]; RR, 0.14; 95% CI, 0.02-1.10; p = 0.049). CONCLUSIONS: This program, if implemented correctly, has the potential to decrease the rate of ACL injury in competitive soccer players. In addition, this may also enhance the development and dissemination of injury prevention protocols and may mitigate risk to athletes who utilize the program consistently. Further studies are necessary to analyze the cost-effectiveness of the program implementation and to analyze the efficacy of the FIFA 11+ in the female collegiate soccer cohort. LEVEL OF EVIDENCE: Level I, therapeutic study.

Editorial Commentary: The Acellular Osteochondral Allograft, the Emperor Has New Clothes.

For larger lesions (>2.5-cm2), clinical evidence and practice have shown that fresh osteochondral allograft have good durability, with 88% return to sport and greater than 75% 10-year survival rates for treatment of large femoral condyle lesions. That said, the use of fresh osteochondral allografts in clinical practice is limited by the availability of acceptable donor tissues for eligible patients in a timely fashion. Significant diminution of chondrocyte viability and density occurs during the preservation and storage period. All osteochondral allografts are not equal in performance and outcome. Chondrocyte density and viability are critical for successful transplantation and outcome in the short and long term. This commentary highlights the high failure rates of tissue when it is acellular.

Editorial Commentary: Focal Cartilage Defects in Young Patients Indicate Autologous Chondrocyte Implantation Sooner Rather Than Later.

Articular cartilage lesions, whether acute or chronic, are among the most common and difficult-to-treat conditions of the knee in the adolescent and athletic population. The results from a study in this issue as well as some in the previous literature suggest that autologous chondrocyte implantation yields long-term improvement in function and symptoms and may be a viable treatment for young to adult athletes or patients with high physical demands and a long active lifespan. No intervention in the young symptomatic patient will yield inferior results because it appears that no treatment over time has deleterious effects. Treatment in young athletes should include (1) early stabilization of ligament injuries, (2) resurfacing chondral defects, (3) correction of malalignment, (4) restoration of meniscal integrity, and (5) utilization of a chondroprotective strategy with orthobiological interventions.

Management of knee articular cartilage injuries in athletes: chondroprotection, chondrofacilitation, and resurfacing.

UNLABELLED: Articular cartilage defects of the knee are common among athletes where the physical demands of sport result in significant stresses on joints. Chondral defects are associated with pain and functional impairment that limit sporting participation and may progress to joint degeneration and frank arthritis. Management of established chondral lesions aims to allow athletes to return to high-impact sports and can be considered in terms of protection of existing cartilage, chondrofacilitation, and resurfacing. Repaired and regenerated cartilage must closely resemble and function like normal hyaline cartilage, and this ability may be the most significant factor for the return to sport. Based on our experiences and the available literature, we outline how athletes can best protect their cartilage, how physicians can facilitate intrinsic repair of established lesions, and which methods of cartilage restoration or resurfacing should be used in different situations. LEVEL OF EVIDENCE: IV.

Cartilage issues in football-today's problems and tomorrow's solutions.

Articular cartilage injury is prevalent in football players and results from chronic joint stress or acute traumatic injuries. Articular cartilage injury can often result in progressive painful impairment of joint function and limit sports participation. Management of articular cartilage injury in athletes aims to return the player to competition, and requires effective and durable joint surface restoration that resembles normal hyaline articular cartilage that can withstand the high joint stresses of football. Existing articular cartilage repair techniques can return the athlete with articular cartilage injury to high-impact sports, but treatment does not produce normal articular cartilage, and this limits the success rate and durability of current cartilage repair in athletes. Novel scientific concepts and treatment techniques that apply modern tissue engineering technologies promise further advancement in the treatment of these challenging injuries in the high demand athletic population. We review the current knowledge of cartilage injury pathophysiology, epidemiology and aetiology, and outline existing management algorithms, developing treatment options and future strategies to manage articular cartilage injuries in football players.