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.

Three-Month Complication Rate of Ultrasound-Guided Soft Tissue Surgical Procedures Across Six Sports Medicine Clinics.

OBJECTIVES: To 1) determine the types and frequency of complications within 3 months following ultrasound-guided surgical procedures, and 2) identify any patient demographics, co-morbidities, or procedural characteristics that were associated with an increased risk of complications. METHODS: A retrospective chart review was performed at six Sports Medicine clinics across the United States. The Clavien-Dindo classification was used to categorize procedural complications on a 5-point scale from 1, representing any deviation in post-procedure care without requiring pharmacological or invasive treatment to 5, representing death. Generalized Estimating Equations for binomial outcomes with a logit link were used to estimate the overall and procedure-specific 3-month complication rates. RESULTS: Among 1902 patients, 8.1% (n = 154) had diabetes and 6.3% (n = 119) were current smokers. The analysis included 2,369 procedures, which were performed in either the upper extremity (44.1%, n = 1045) or lower extremity (55.2%, n = 1308) regions. The most common procedure was ultrasound-guided tenotomy (69.9%, n = 1655). Additional procedures included, trigger finger release (13.1%, n = 310), tendon scraping (8.0%, n = 189), carpal tunnel release (5.4%, n = 128), soft tissue release (2.1%, n = 50), and compartment fasciotomy (1.6%, n = 37). Overall, there was a complication rate of 1.2% (n = 29 complications; 95% CI: 0.8-1.7%). Individual procedures had complication rates that ranged from 0 to 2.7%. There were 13 Grade I complications in 13 patients, 12 Grade II complications in 10 patients, 4 Grade III complications in 4 patients, and 0 Grade IV or V complications. No associations between complication risk and any patient demographics (age, sex, BMI), co-morbidities (diabetes, smoker), or procedure characteristics (type, region) were identified. CONCLUSION: This retrospective review provides an evidence-based estimate supporting the low level of risk associated with ultrasound-guided surgical procedures for patients from a variety of geographical settings who are seeking care at private and academic-affiliated clinics.

Modifying Orthobiological PRP Therapies Are Imperative for the Advancement of Treatment Outcomes in Musculoskeletal Pathologies.

Autologous biological cellular preparations have materialized as a growing area of medical advancement in interventional (orthopedic) practices and surgical interventions to provide an optimal tissue healing environment, particularly in tissues where standard healing is disrupted and repair and ultimately restoration of function is at risk. These cellular therapies are often referred to as orthobiologics and are derived from patient's own tissues to prepare point of care platelet-rich plasma (PRP), bone marrow concentrate (BMC), and adipose tissue concentrate (ATC). Orthobiological preparations are biological materials comprised of a wide variety of cell populations, cytokines, growth factors, molecules, and signaling cells. They can modulate and influence many other resident cells after they have been administered in specific diseased microenvironments. Jointly, the various orthobiological cell preparations are proficient to counteract persistent inflammation, respond to catabolic reactions, and reinstate tissue homeostasis. Ultimately, precisely delivered orthobiologics with a proper dose and bioformulation will contribute to tissue repair. Progress has been made in understanding orthobiological technologies where the safety and relatively easy manipulation of orthobiological treatment tools has been demonstrated in clinical applications. Although more positive than negative patient outcome results have been registered in the literature, definitive and accepted standards to prepare specific cellular orthobiologics are still lacking. To promote significant and consistent clinical outcomes, we will present a review of methods for implementing dosing strategies, using bioformulations tailored to the pathoanatomic process of the tissue, and adopting variable preparation and injection volume policies. By optimizing the dose and specificity of orthobiologics, local cellular synergistic behavior will increase, potentially leading to better pain killing effects, effective immunomodulation, control of inflammation, and (neo) angiogenesis, ultimately contributing to functionally restored body movement patterns.

Mesenchymal stem cells for subchondral bone marrow lesions: From bench to bedside.

Subchondral bone marrow lesions (BMLs) are areas of disease within subchondral bone that appear as T1 hypointense and T2 hyperintense ill-defined areas of bone marrow on magnetic resonance imaging. The most common bone marrow lesions include subchondral lesions related to osteoarthritis, osteochondral defects, and avascular necrosis. Emerging therapies include autologous biologic therapeutics, in particular mesenchymal stem cells (MSCs), to maintain and improve cartilage health; MSCs have become a potential treatment option for BMLs given the unmet need for disease modification. Active areas in the preclinical research of bone marrow lesions include the paracrine function of MSCs in pathways of angiogenesis and inflammation, and the use of bioactive scaffolds to optimize the environment for implanted MSCs by facilitating chondrogenesis and higher bone volumes. A review of the clinical data demonstrates improvements in pain and functional outcomes when patients with knee osteoarthritis were treated with MSCs, suggesting that BM-MSCs can be a safe and effective treatment for patients with painful knee osteoarthritis with or without bone marrow lesions. Preliminary data examining MSCs in osteochondral defects suggest they can be beneficial as a subchondral injection alone, or as a surgical augmentation. In patients with hip avascular necrosis, those with earlier stage disease have improved outcomes when core decompression is augmented with MSCs, whereas patients in later stages post-collapse have equivalent outcomes with or without MSC treatment. While the evidence for the use of MSCs in conditions with associated bone marrow lesions seems promising, there remains a need for continued investigation into this treatment as a viable treatment option.

Amniotic dehydrated cell and protein concentrate versus corticosteroid in knee osteoarthritis: preliminary findings.

Objectives: The purpose is to report preliminary data on clinical response to dehydrated cell and protein concentrate (dCPC) versus corticosteroid (CSI). Design: A single-site prospective, randomized controlled single-blinded trial of patients with knee osteoarthritis. Methods: Pain and function were assessed using a visual analog scale (VAS), the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Emory Quality of Life (EQOL) measure at 1, 2, 3, 6, 9 and 12 months. Results: 51 patients were enrolled at the time of analysis (27 dCPC, 24 CSI). Both groups demonstrated improvement on the VAS, KOOS and EQOL. Largest differences were observed at 2 (p = 0.05), 3 (p = 0.012) and 6 months (p < 0.001) with a decrease of 1.66 in VAS at 6 months for dCPC (95% CI: -2.67 to -0.65) and 1.34 (95% CI: -2.37 to -0.3) for CSI. Time-averaged measures showed no difference between groups (p = 0.20). Limited data at 9 and 12 months trended toward improvement in the dCPC group. Conclusion: dCPC products may be used as a treatment for knee osteoarthritis. Larger trials are warranted. Clinical Trial Registration: NCT03710005 (ClinicalTrials.gov).

The purpose of this study was to discuss preliminary data from a clinical trial comparing a single injection of an amniotic-derived tissue product (dehydrated cell and protein concentrate [dCPC]) to corticosteroid for the treatment of knee osteoarthritis. The study took place at a single institution. 51 patients were enrolled at the time of analysis (27 dCPC, 24 corticosteroid). Both groups demonstrated improvement in pain and function 6 months after treatment. There was a larger improvement in the amniotic-derived tissue product group, but this did not reach a level of statistical significance. There were limited data beyond 6 months, but this trended toward a continued improvement in the amniotic-derived tissue product group. Findings suggest that these amniotic derived tissue products may be used as a treatment for knee osteoarthritis, but larger studies are needed.

American Medical Society for Sports Medicine sports ultrasound curriculum for sports medicine fellowships.

Sports ultrasound is commonly used by sports medicine physicians to enhance diagnostic and procedural accuracy. This expert consensus statement serves as an update to the 2015 American Medical Society for Sports Medicine recommended sports ultrasound curriculum for sports medicine fellowships. Although written in the context of the American sports medicine fellowship training model, we present a stepwise progression in both diagnostic and interventional sports ultrasound that may be applicable to the broader sports medicine community. The curriculum is divided into 12 units with each unit including didactic instructional sessions, practical hands-on instruction, independent scanning practice sessions and mentored clinical experience. To assist with prioritisation of learning, we have organised relevant pathology and procedures as essential, desirable and optional The expanded content can serve as an outline for continuing education postfellowship or for any physician to further advance their sports ultrasound knowledge and skill. We also provide updated scanning protocols, sample milestones and a sample objective structured clinical examination to aid fellowships with implementation of the curriculum and ongoing assessment of fellow progress.

American Medical Society for Sports Medicine Position Statement: Principles for the Responsible Use of Regenerative Medicine in Sports Medicine.

ABSTRACT: Many sports medicine physicians are currently considering introducing regenerative medicine into their practice. Regenerative medicine and the subclassification of orthobiologics are a complicated topic and have produced widely varying opinions. Although there is concern by government regulators, clinicians, scientists, patient advocacy organizations, and the media regarding the use of regenerative medicine products, there is also excitement about the potential benefits with growing evidence that certain regenerative medicine products are safe and potentially efficacious in treating musculoskeletal conditions. Sports medicine physicians would benefit from decision-making guidance about whether to introduce orthobiologics into their practice and how to do it responsibly. The purpose of this position statement is to provide sports medicine physicians with information regarding regenerative medicine terminology, a brief review of basic science and clinical studies within the subclassification of orthobiologics, regulatory considerations, and best practices for introducing regenerative medicine into clinical practice. This information will help sports medicine physicians make informed and responsible decisions about the role of regenerative medicine and orthobiologics in their practice.

American Medical Society for Sports Medicine Sports Ultrasound Curriculum for Sports Medicine Fellowships.

ABSTRACT: Sports ultrasound is commonly used by sports medicine physicians to enhance diagnostic and procedural accuracy. This expert consensus statement serves as an update to the 2015 American Medical Society for Sports Medicine recommended sports ultrasound curriculum for sports medicine fellowships. Although written in the context of the American sports medicine fellowship training model, we present a stepwise progression in both diagnostic and interventional sports ultrasound that may be applicable to the broader sports medicine community. The curriculum is divided into 12 units with each unit including didactic instructional sessions, practical hands-on instruction, independent scanning practice sessions, and mentored clinical experience. To assist with prioritization of learning, we have organized relevant pathology and procedures as essential, desirable, and optional. The expanded content can serve as an outline for continuing education postfellowship or for any physician to further advance their sports ultrasound knowledge and skill. We also provide updated scanning protocols, sample milestones, and a sample objective structured clinical examination (OSCE) to aid fellowships with implementation of the curriculum and ongoing assessment of fellow progress.

Biologics.

Biologics are a growing field that has shown immense promise for the treatment of musculoskeletal conditions both in orthopedic sports medicine and interventional pain management. These procedures utilize injection of supraphysiologic levels of platelets and growth factors to invoke the body's own inflammatory cascade to augment the healing of many bony and soft tissue conditions. While many patients improve with conservative care, there is a need to address the gap between those that improve with rehabilitation alone and those who ultimately require operative management. Orthobiologic procedures have the potential to fill this void. The purpose of this review is to summarize the basic science, evidence for use, and post-injection rehabilitation concepts of platelet-rich plasma (PRP) and mesenchymal stromal cells (MSCs) as they pertain to joints, tendons, ligaments, and the spine.

Platelet-Rich Plasma: New Performance Understandings and Therapeutic Considerations in 2020.

Emerging autologous cellular therapies that utilize platelet-rich plasma (PRP) applications have the potential to play adjunctive roles in a variety of regenerative medicine treatment plans. There is a global unmet need for tissue repair strategies to treat musculoskeletal (MSK) and spinal disorders, osteoarthritis (OA), and patients with chronic complex and recalcitrant wounds. PRP therapy is based on the fact that platelet growth factors (PGFs) support the three phases of wound healing and repair cascade (inflammation, proliferation, remodeling). Many different PRP formulations have been evaluated, originating from human, in vitro, and animal studies. However, recommendations from in vitro and animal research often lead to different clinical outcomes because it is difficult to translate non-clinical study outcomes and methodology recommendations to human clinical treatment protocols. In recent years, progress has been made in understanding PRP technology and the concepts for bioformulation, and new research directives and new indications have been suggested. In this review, we will discuss recent developments regarding PRP preparation and composition regarding platelet dosing, leukocyte activities concerning innate and adaptive immunomodulation, serotonin (5-HT) effects, and pain killing. Furthermore, we discuss PRP mechanisms related to inflammation and angiogenesis in tissue repair and regenerative processes. Lastly, we will review the effect of certain drugs on PRP activity, and the combination of PRP and rehabilitation protocols.

Bone Marrow Concentrate (BMC) Therapy in Musculoskeletal Disorders: Evidence-Based Policy Position Statement of American Society of Interventional Pain Physicians (ASIPP).

BACKGROUND: The use of bone marrow concentrate (BMC) for treatment of musculoskeletal disorders has become increasingly popular over the last several years, as technology has improved along with the need for better solutions for these pathologies. The use of cellular tissue raises a number of issues regarding the US Food and Drug Administration's (FDA) regulation in classifying these treatments as a drug versus just autologous tissue transplantation. In the case of BMC in musculoskeletal and spine care, this determination will likely hinge on whether BMC is homologous to the musculoskeletal system and spine. OBJECTIVES: The aim of this review is to describe the current regulatory guidelines set in place by the FDA, specifically the terminology around "minimal manipulation" and "homologous use" within Regulation 21 CFR Part 1271, and specifically how this applies to the use of BMC in interventional musculoskeletal medicine. METHODS: The methodology utilized here is similar to the methodology utilized in preparation of multiple guidelines employing the experience of a panel of experts from various medical specialties and subspecialties from differing regions of the world. The collaborators who developed these position statements have submitted their appropriate disclosures of conflicts of interest. Trustworthy standards were employed in the creation of these position statements. The literature pertaining to BMC, its effectiveness, adverse consequences, FDA regulations, criteria for meeting the standards of minimal manipulation, and homologous use were comprehensively reviewed using a best evidence synthesis of the available and relevant literature. RESULTS/Summary of Evidence: In conjunction with evidence-based medicine principles, the following position statements were developed: Statement 1: Based on a review of the literature in discussing the preparation of BMC using accepted methodologies, there is strong evidence of minimal manipulation in its preparation, and moderate evidence for homologous utility for various musculoskeletal and spinal conditions qualifies for the same surgical exemption. Statement 2: Assessment of clinical effectiveness based on extensive literature shows emerging evidence for multiple musculoskeletal and spinal conditions. • The evidence is highest for knee osteoarthritis with level II evidence based on relevant systematic reviews, randomized controlled trials and nonrandomized studies. There is level III evidence for knee cartilage conditions. • Based on the relevant systematic reviews, randomized trials, and nonrandomized studies, the evidence for disc injections is level III. • Based on the available literature without appropriate systematic reviews or randomized controlled trials, the evidence for all other conditions is level IV or limited for BMC injections. Statement 3: Based on an extensive review of the literature, there is strong evidence for the safety of BMC when performed by trained physicians with the appropriate precautions under image guidance utilizing a sterile technique. Statement 4: Musculoskeletal disorders and spinal disorders with related disability for economic and human toll, despite advancements with a wide array of treatment modalities. Statement 5: The 21st Century Cures Act was enacted in December 2016 with provisions to accelerate the development and translation of promising new therapies into clinical evaluation and use. Statement 6: Development of cell-based therapies is rapidly proliferating in a number of disease areas, including musculoskeletal disorders and spine. With mixed results, these therapies are greatly outpacing the evidence. The reckless publicity with unsubstantiated claims of beneficial outcomes having putative potential, and has led the FDA Federal Trade Commission (FTC) to issue multiple warnings. Thus the US FDA is considering the appropriateness of using various therapies, including BMC, for homologous use. Statement 7: Since the 1980's and the description of mesenchymal stem cells by Caplan et al, (now called medicinal signaling cells), the use of BMC in musculoskeletal and spinal disorders has been increasing in the management of pain and promoting tissue healing. Statement 8: The Public Health Service Act (PHSA) of the FDA requires minimal manipulation under same surgical procedure exemption. Homologous use of BMC in musculoskeletal and spinal disorders is provided by preclinical and clinical evidence. Statement 9: If the FDA does not accept BMC as homologous, then it will require an Investigational New Drug (IND) classification with FDA (351) cellular drug approval for use. Statement 10: This literature review and these position statements establish compliance with the FDA's intent and corroborates its present description of BMC as homologous with same surgical exemption, and exempt from IND, for use of BMC for treatment of musculoskeletal tissues, such as cartilage, bones, ligaments, muscles, tendons, and spinal discs. CONCLUSIONS: Based on the review of all available and pertinent literature, multiple position statements have been developed showing that BMC in musculoskeletal disorders meets the criteria of minimal manipulation and homologous use. KEY WORDS: Cell-based therapies, bone marrow concentrate, mesenchymal stem cells, medicinal signaling cells, Food and Drug Administration, human cells, tissues, and cellular tissue-based products, Public Health Service Act (PHSA), minimal manipulation, homologous use, same surgical procedure exemption.

Functional Outcomes Following Microfragmented Adipose Tissue Versus Bone Marrow Aspirate Concentrate Injections for Symptomatic Knee Osteoarthritis.

This study aimed to determine whether autologous orthobiologic tissue source affects pain and functional outcomes in patients with symptomatic knee osteoarthritis (OA) who received microfragmented adipose tissue (MFAT) or bone marrow aspirate concentrate (BMAC) injection. We retrospectively reviewed prospectively collected data from patients who received BMAC or MFAT injection for symptomatic knee OA. Patients completed baseline and follow-up surveys. Each survey included the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire, Emory Quality of Life (EQOL) questionnaire, and Visual Analog Scale (VAS) for pain. The follow-up responses were compared with baseline for all patients and between BMAC and MFAT groups. A total of 110 patients met inclusion criteria, with 76 patients (BMAC 41, MFAT 35) and 106 knees (BMAC 58, MFAT 48) having appropriate follow-up data. The BMAC group included 17 females and 24 males, with a mean age of 59 ± 11 years. The MFAT group included 23 females and 12 males, with a mean age of 63 ± 11 years. Minimum follow-up time was 0.5 years. Mean follow-up time was 1.80 ± 0.88 years for BMAC and 1.09 ± 0.49 years for MFAT. Both groups had significant improvement in EQOL, VAS, and all KOOS parameters preprocedure versus postprocedure (p < .001). There was not a significant difference when comparing postprocedure scores between groups (p = .09, .38, .63, .94, .17, .15, .70, respectively). These data demonstrate significant improvement in pain and function with both MFAT and BMAC injections in patients with symptomatic knee OA without a significant difference in improvement when comparing the two autologous tissue sources. Stem Cells Translational Medicine 2019;8:1149-1156.

Assessing clinical implications and perspectives of the pathophysiological effects of erythrocytes and plasma free hemoglobin in autologous biologics for use in musculoskeletal regenerative medicine therapies. A review.

Autologous biologics, defined as platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMC), are cell-based therapy treatment options in regenerative medicine practices, and have been increasingly used in orthopedics, sports medicine, and spinal disorders. These biological products are produced at point-of-care; thereby, avoiding expensive and cumbersome culturing and expansion techniques. Numerous commercial PRP and BMC systems are available but reports and knowledge of bio-cellular formulations produced by these systems are limited. This limited information hinders evaluating clinical and research outcomes and thus making conclusions about their biological effectiveness. Some of their important cellular and protein properties have not been characterized, which is critical for understanding the mechanisms of actions involved in tissue regenerative processes. The presence and role of red blood cells (RBCs) in any biologic has not been addressed extensively. Furthermore, some of the pathophysiological effects and phenomena related to RBCs have not been studied. A lack of a complete understanding of all of the biological components and their functional consequences hampers the development of clinical standards for any biological preparation. This paper aims to review the clinical implications and pathophysiological effects of RBCs in PRP and BMC; emphasizes hemolysis, eryptosis, and the release of macrophage inhibitory factor; and explains several effects on the microenvironment, such as inflammation, oxidative stress, vasoconstriction, and impaired cell metabolism.

Platelet-rich plasma versus Tenex in the treatment of medial and lateral epicondylitis.

BACKGROUND: Medial epicondylitis and lateral epicondylitis are among the most common elbow pathologies affecting people aged between 40 and 50 years. Although epicondylitis is often a self-limiting condition that improves with conservative treatment, the condition can be difficult to eradicate. The purpose of this study was to compare the effectiveness of platelet-rich plasma (PRP) injections and ultrasound-guided percutaneous tenotomy (Tenex) for the treatment of medial or lateral epicondylitis. Our hypothesis was that the Tenex procedure would not be inferior to PRP injections in the treatment of medial or lateral epicondylitis. METHODS: In this retrospective review, 62 of 75 patients were available for contact via phone and e-mail to complete post-procedure patient-reported outcome surveys. Subjective assessment of pain and function included a visual analog scale for pain; the Quick Disabilities of the Arm, Shoulder and Hand questionnaire; and the EuroQol-5D questionnaire. The inclusion criteria included age of 18 years or older and previous failure of nonoperative treatment. RESULTS: The average ages in the PRP and Tenex groups were 47 years and 51 years, respectively. The PRP cohort (n = 32) included 10 female and 22 male patients, whereas the Tenex cohort (n = 30) included 12 female and 18 male patients. The PRP and Tenex groups both demonstrated clinical and statistical improvement in visual analog scale pain scores; Quick Disabilities of the Arm, Shoulder and Hand scores; and EuroQol-5D scores. No statistically significant difference was found between the 2 treatment modalities. CONCLUSION: The PRP and Tenex procedures were both successful in producing clinically and statistically significant improvements in pain, function, and quality of life.

Ultrasound-Guided Percutaneous Needle Tenotomy for Chronic Tensor Fascia Lata Tendinopathy: A Case Series and Description of Sonographic Findings.

Proximal tensor fascia lata tendinopathy at its origin on the anterior superior iliac crest is one potential cause of lateral hip pain. However, there is limited literature regarding the mechanism, disease course, or management of this condition. There is growing evidence supporting the effective treatment of percutaneous needle tenotomy (PNT) for chronic tendinopathy. Only a single case series has examined the efficacy of PNT for tendinopathy about the hip and pelvis. Presented here are examples of 2 cases of chronic recalcitrant proximal ultrasound confirmed tensor fascia lata (tendinopathy effectively treated with ultrasound-guided PNT. LEVEL OF EVIDENCE: IV.

Ultrasound Findings of Delayed-Onset Muscle Soreness.

The purpose of this series was to retrospectively characterize the ultrasound findings of delayed-onset muscle soreness (DOMS). The Institutional Review Board approved our study, and informed consent was waived. A retrospective search of radiology reports using the key phrase "delayed-onset muscle soreness" and key word "DOMS" from 2001 to 2015 and teaching files was completed to identify cases. The sonograms were reviewed by 3 fellowship-trained musculoskeletal radiologists by consensus. Sonograms were retrospectively characterized with respect to echogenicity (hypoechoic, isoechoic, or hyperechoic), distribution of muscle involvement, and intramuscular pattern (focal versus diffuse and well defined versus poorly defined). Images were also reviewed for muscle enlargement, fluid collection, muscle fiber disruption, and increased flow on color or power Doppler imaging. There were a total of 6 patients identified (5 male and 1 female). The average age was 22 years (range, 7-44 years). Of the 6 patients, there were a total of 11 affected muscles in 7 extremities (1 bilateral case). The involved muscles were in the upper extremity: triceps brachii in 27% (3 of 11), biceps brachii in 18% (2 of 11), brachialis in 18% (2 of 11), brachioradialis in 18% (2 of 11), infraspinatus in 9% (1 of 11), and deltoid in 9% (1 of 11). On ultrasound imaging, the abnormal muscle was hyperechoic in 100% (11 of 11), well defined in 73% (8 of 11), poorly defined in 27% (3 of 11), diffuse in 73% (8 of 11), and focal in 27% (3 of 11). Increased muscle size was found in 82% (9 of 11) and minimal hyperemia in 87.5% (7 of 8). The ultrasound findings of DOMS include hyperechoic involvement of an upper extremity muscle, most commonly appearing well defined and diffuse with increased muscle size and minimal hyperemia.