Sports Medicine Concepts for the Emergency Physician
November 4, 2012
Sports Medicine Concepts for the Emergency Physician
Authors:
Manish Mannan, MD, Fellow, Wright State University/Kettering Sports Medicine, Integrated Fellowship in Sports Medicine, Dayton, OH.
James Tytko, MD, Clinical Associate Professor, Department of Family Medicine and Department of Emergency Medicine Program Director, Wright State University/Kettering Sports Medicine Integrated Fellowship in Sports Medicine, Dayton, OH.
Peer Reviewer:
Christopher J. Haines, DO, FAAP, FACEP, Assistant Professor of Emergency Medicine and Pediatrics, Drexel University College of Medicine; Director, Department of Emergency Medicine and Medical Director, Critical Care Transport Team, St. Christopher's Hospital for Children, Philadelphia, PA.
This article was adapted from one that originally appeared in the June 2012 issue of Primary Care Reports.
Introduction
Encouraging individuals to be active through recreational and competitive athletics has led to increased participation in organized sports. With this comes an increase in sport-related injuries that a physician may see on the athletic field or in the emergency department. Sports medicine is a broad field that encompasses prevention, assessment of acute injuries, and rehabilitation and reconditioning to recover function. Emergency physicians may have an interest in sports medicine or may actually practice components of sports medicine as team and sideline physicians at athletic events. This review will discuss methods to assess concussions seen in sports, evolving concepts for ankle and anterior cruciate ligament injuries in the knee, and the use of musculoskeletal ultrasound to evaluate sport-related injuries. The article will conclude with a discussion of platelet-rich plasma and prolotherapy to accelerate healing, two controversial modalities that have seen limited use in high-performance professional athletes, but may also see use in the high-functioning amateur athlete who desires a more rapid recovery.
Injuries in Sports Medicine
In addition to the 7.6 million students who participate in high school sports annually,,1 more than 30 million athletes participate in club and recreational sports.2,3 In the United States, an estimated 7 million children and adults receive medical care for sports injury each year.4 The highest rates occur in children ages 5-14 years (59.3/1000 persons) and in the 15- to 24-year-old age group (56.4/1000 persons). The rate of injury in males is more than twice that in females. In a 1999 study, sports injuries among high school athletes resulted in approximately 2 million injuries, 500,000 doctor visits, and 30,000 hospitalizations annually.5,6 The most common injuries in sports medicine are sprains, strains, fractures, and concussions, but less common injuries include eye injuries, dental injuries, neck and cervical injuries, dehydration, and heat illnesses.4,7 The most common reasons for sports-related emergency department visits for children and adolescents are injuries associated with basketball and pedal cycling (almost 900,000 a year), football and baseball injuries (250,000 visits per year), and soccer injuries (100,000 visits per year). The findings do not suggest that these sports are necessarily more dangerous; there may be more people engaging in these activities. Injuries on the playground account for about 137,000 emergency department visits yearly.4,8
Concussions
An estimated 300,000 concussions occur in sports every year.9 A study summarizing 16 years of NCAA injury surveillance data showed an increase in the concussion injury rate per 1000 athletic exposures from 0.17 in 1988-1999 to 0.34 in 2003-2004.10 One athletic exposure is defined as one athlete participating in one practice or game. This increase in the concussion injury rate is partially because of an increase in sports activity and partially because of increased awareness and understanding of concussion. The most recent consensus statement on concussion was released at the Third International Conference on Concussion in Sports held in Zurich in 2008. (See Table 1.)
Table 1: Definition of Concussion from the Third International Conference on Concussion19
Concussion is defined as a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces. Several common features that incorporate clinical, pathologic, and biomechanical injury constructs that may be utilized in defining the nature of a concussive head injury include:
|
Concussion is caused by rotational and angular forces to the brain.11,12 These shear forces disrupt neural membranes, allowing potassium efflux into extracellular space. The increase in calcium and excitatory amino acids are followed by further potassium efflux into extracellular space. This leads to suppression of neuronal activity.11-15 The disruption of autonomic regulation can persist for many weeks, and the brain may be vulnerable to additional injury such as extremes of blood pressure. A catecholamine surge from the second impact to the head or body may cause vascular congestion, cerebral edema, increased intracranial pressure, and, ultimately, coma and death.14 There have been a few documented cases of the "second impact syndrome," and all of these deaths have occurred in persons younger than 20 years of age.11,14
The suspected diagnosis of concussion can include one or more of the following clinical domains:16
(a) Symptoms — somatic (e.g., headache, pressure in the head, neck pain, nausea or vomiting, dizziness, tinnitus, blurred vision, sensitivity to light, sensitivity to sound, fatigue or low energy); cognitive (e.g., feeling like in a fog, feeling slowed down, "don't feel right," difficulty concentrating, difficulty remembering, confusion, slowed reaction time, inability to focus); and/or emotional (e.g., lability, personality changes, anxiety, depression);
(b) Physical signs (e.g., loss of consciousness, seizure or convulsions, amnesia, balance problems);
(c) Behavioral changes (e.g., irritability, sadness);
(d) Cognitive impairment (e.g., slowed reaction times);
(e) Sleep disturbance (e.g., drowsiness, increased or decreased sleep, difficulty initiating sleep).
Baseline self-reported symptom (SRS) scales can be used at the time of pre-participation exam. This baseline score can assist in determining when the injury has resolved in a case in which an athlete sustains a concussion. However, athletes may present with concussion-related symptoms at baseline. A recent study showed that a history of previous concussion, acute fatigue, physical illness, or orthopedic injury can alter normal baseline responses. If the athlete is currently experiencing fatigue, physical illness, or orthopedic injury, baseline testing should be postponed until the athlete improves.17
In a recent study evaluating the sex differences in the concussion symptoms of high school athletes, there was no difference in the number of symptoms reported, but there was a difference in the type of symptoms reported. Males reported amnesia, confusion, and disorientation more frequently than females, whereas females reported more drowsiness and phonophobia than did males. No differences were observed for the symptom resolution time in this study.18
An athlete with concussion may be evaluated initially in the emergency department. In addition to the points outlined above, the key features of this exam should include a determination of the need for emergent neuroimaging to exclude a more severe brain injury involving a structural abnormality. It is worth mentioning that conventional structural neuroimaging is generally normal in concussive injury. Brain CT or MRI brain scan contributes little to concussion evaluation but should be employed whenever suspicion of an intracerebral structural lesion exists. Examples of such situations may include prolonged disturbance of conscious state, focal neurological deficit, evidence of skull fracture, or worsening symptoms. Once a serious structural injury is excluded, an evaluation involving a symptom checklist, sideline assessment tools, a neuropsychological test, and postural stability test are used to diagnose concussion.16 Although none are exclusively effective, combining these tools can increase sensitivity and specificity. (See Table 2.)
Table 2: Various Assessment Tools Used in Concussion Diagnosis and Management24
Type |
Examples |
Symptoms checklists |
Graded Symptom scale Head Injury Scale Post Concussive Symptoms Scale McGill Abbreviated Concussion Evaluation Concussion Symptom Inventory |
Neuropsychological testing |
Written Tests Trail Making Test Digit Symbol Substitution Test Controlled Oral Word Association Test Hopkins Verbal Association Test Stroop Color and Word Test Computer Based Tests HeadMinder™ (http://www.headminder.com/site/home.html) CogState® Sport (http://www.cogstate.com/go/sport) ImPACT® (http://www.impacttest.com/) ANAM4™ - The Automated Neuropsychological Assessment Metrics, Version 4 (http://vistalifesciences.com/anam-faq.html) |
Postural stability testing |
BESS (Balance Error Scoring System) modified version SOT (Sensory Organization Test) |
Sideline assessment tools |
SAC (Standardized Assessment of Concussion) SCAT 2 (Sport Concussion Assessment Tool) |
Standard orientation questions are not sensitive enough to identify subtle changes caused by concussion. The Standardized Assessment of Concussion (SAC) was developed as a tool for the immediate assessment of concussion in athletes. The SAC tests domains of neuropsychological function that are most commonly affected by concussion: orientation, immediate memory, concentration, and delayed recall. (See Table 3.) Concussed athletes typically decrease their SAC score by 3 points from their baseline or when compared to uninjured controls. The limitation of the SAC test is the need for baseline measurements to maximize its sensitivity.
Table 3: Standardized Assessment of Concussion (SAC)
Introduction: I am going to ask you some questions. Please listen carefully and give your best effort. |
||
Orientation: I am going to ask you some questions about today. Scoring: 1 point for each correct answer (Maximum score 5) |
What month is it? What's the date today? What's the day of the week? What year is it? What time is it right now? (within 1 hr) |
|
Immediate Memory: I am going to test your memory. I will read you a list of words and when I am done, repeat back as many words as you can remember, in any order (Trial 1) I am going to repeat that list again (Trial 2). Repeat back as many words as you can remember in any order, even if I said the word before. Repeat again (Trial 3) Complete all 3 trials regardless of score on trials 1 and 2. Scoring: 1 point for each correct response. Total score equals sum across all 3 trails. (Maximum score 15) Do not inform the subject that delayed recall will be tested |
Elbow Apple Carpet Saddle Bubble |
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Concentration Digits in Reverse Order: I am going to read you a string of numbers and when I am done, you repeat them back to me backwards, in reverse order of how I read them to you. For example, if I say 7-1-9, you would say 9-1-7. If correct, go to next string length, if incorrect, read trial 2. Scoring: 1 point for each string length. Stop after incorrect on both trials. (maximum score 4) |
4-9-3 3-8-1-4 6-2-9-7-1 7-1-8-4-6-2 |
6-2-9 3-2-7-9 1-5-2-8-6 5-3-9-1-4-8 |
Concentration Months in Reverse Order: Now tell me the months of the year in reverse order. Start with the last month and go backward. So you'll start with December, NovemberGo ahead. Scoring: 1 point for entire sequence correct (Maximum score 1) |
Dec-Nov-Oct-Sept-Aug-Jul-Jun-May-Apr-Mar-Feb-Jan |
|
Delayed Recall: Do you remember that list of words I read a few times earlier? Tell me as many words from the list as you can remember in any order. Scoring: 1 point for each word recalled. (Maximum score 5) |
Elbow Apple Carpet Saddle Bubble |
|
SAC Scoring Summary: (Maximum score 30) |
Orientation: 5 Immediate memory: 15 Concentration digits in reverse order: 4 Concentration months in reverse order: 1 Delayed recall: 5
|
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The orientation questions in the SAC have been analyzed and found "too easy" to detect subtle orientation changes from concussion.20 The modified Maddocks questions, which are part of SCAT 2, are more challenging and, thus, more sensitive for sideline assessment. (See Table 4.)
Table 4: Modified Maddocks Score Sideline Assessment Tool41
The physician should say to the patient: "I am going to ask you a few questions, please listen carefully and give your best effort." |
||
Score 1 point for each correct answer. |
||
Question |
Incorrect Answer |
Correct Answer |
At what venue are we today? |
0 |
1 |
Which half is it now? |
0 |
1 |
Who scored last in this match? |
0 |
1 |
What team did you play last week/game? |
0 |
1 |
Did your team win the last game? |
0 |
1 |
Total Maddocks Score |
||
It appears that postural stability testing provides a useful tool for objectively assessing the motor domain of neurological functioning, and is a valid addition to the assessment of athletes suffering from concussion, particularly where symptoms or signs indicate a balance component. A modified Balance Error Scoring System (BESS) 6 can be used for assessment. (See Table 5.)
Table 5: Balance Error Scoring System — Modified (BESS) 664
This balance testing is based on a modified version of the Balance Error Scoring System (BESS) 6. A stopwatch or watch with a second hand is required for this testing. Balance Testing "I am now going to test your balance. Please take your shoes off, roll up your pant legs above ankle (if applicable), and remove any ankle taping (if applicable). This test will consist of three 20-second tests with different stances." (a) Double-leg Stance: "The first stance is standing with your feet together with your hands on your hips and with your eyes closed. You should try to maintain stability in that position for 20 seconds. I will be counting the number of times you move out of this position. I will start timing when you are set and have closed your eyes." (b) Single-leg Stance: "If you were to kick a ball, which foot would you use? [This will be the dominant foot] Now stand on your non-dominant foot. The dominant leg should be held in approximately 30 degrees of hip flexion and 45 degrees of knee flexion. Again, you should try to maintain stability for 20 seconds with your hands on your hips and your eyes closed. I will be counting the number of times you move out of this position. If you stumble out of this position, open your eyes and return to the start position and continue balancing. I will start timing when you are set and have closed your eyes." (c) Tandem stance: "Now stand heel-to-toe with your non-dominant foot in back. Your weight should be evenly distributed across both feet. Again, you should try to maintain stability for 20 seconds with your hands on your hips and your eyes closed. I will be counting the number of times you move out of this position. If you stumble out of this position, open your eyes and return to the start position and continue balancing. I will start timing when you are set and have closed your eyes." Balance testing — types of errors 1. Hands lifted off iliac crest 2. Opening eyes 3. Step, stumble, or fall 4. Moving hip into > 30 degrees abduction 5. Lifting forefoot or heel 6. Remaining out of test position > 5 sec Each of the 20-second trials is scored by counting the errors, or deviations from the proper stance, accumulated by the athlete. The examiner will begin counting errors only after the individual has assumed the proper start position. The modified BESS is calculated by adding one error point for each error during the three 20-second tests. The maximum total number of errors for any single condition is 10. If a athlete commits multiple errors simultaneously, only one error is recorded but the athlete should quickly return to the testing position, and counting should resume once subject is set. Subjects who are unable to maintain the testing procedure for a minimum of 5 seconds at the start are assigned the highest possible score, 10, for that testing condition. Which foot was tested: left or right (i.e., which is the non-dominant foot)? Condition Total errors Double-leg stance (feet together) of 10 Single-leg stance (non-dominant foot) of 10 Tandem stance (non-dominant foot at back) of 10 Balance examination score (30 minus total errors) of 30 |
The cornerstone of concussion management is physical and cognitive rest until symptoms resolve and then a gradual program of exertion prior to medical clearance and return to play. A well-known phenomenon called "second impact syndrome" carries the risk of sudden death in an athlete and should be kept in mind while making a return-to-play decision. It may take minutes, hours, days, or weeks to recover from the symptoms. It is inappropriate for a child or adolescent athlete with a concussion to return to play on the same day as injury regardless of the level of athletic performance. During the period of recovery while symptomatic following an injury, it is important to place emphasis on the necessity to have both physical and cognitive rest. Activities that require concentration and attention (e.g., scholastic work, video games, text messaging, etc.) may aggravate symptoms and possibly delay recovery. The recovery and outcome of this injury may be modified by a number of factors that may require more sophisticated management strategies. Once complete symptomatic and cognitive recovery are achieved, an athlete can be started on a graded return-to-play protocol.16,19,21
The application of neuropsychological testing in concussion has been shown to be of clinical importance and is designed to identify subtle cognitive deficits.15 Although in most cases cognitive recovery largely overlaps with the time course of symptom recovery, it has been recognized that cognitive recovery more commonly follows clinical symptom resolution, suggesting that the assessment of cognitive function should be an important component in any return to play modus operandi. Neuropsychological assessment should not be the solitary basis of management decisions; rather, it should be seen as an aid to the clinical decision-making process in combination with a range of clinical domains and investigational results.15,16 Various commercial computer-based screening tools (e.g., ImPACT®) are often utilized in sports clinics to assist in return to play decision making. (See Table 2.) In a majority of cases, neuropsychological testing is not done until the patient is symptom-free. In certain situations (e.g., child and adolescent athletes), testing may be done early while the patient is still symptomatic to assist in determining management. In patients with a complicated history, prolonged recovery time, or requiring medication to control symptoms, a formal neuropsychological evaluation through a neurophysiologist may be required to assist in return to play decision making. Athletes with concerning historical factors or concussive symptoms lasting more than 7-10 days may benefit from referral to an expert in concussion management. Some of these factors may include previous history of concussions, severity, comorbidities like ADHD, and sleep disorders.16
Helmets have been ineffective in the prevention of concussion injury, although a study conducted by Collins et al suggests that a newer design of football helmets (e.g., the Riddell Revolution®, Elyria, OH) may have some protective role from concussion.22 Recently, a new system was developed to evaluate the protective performance of football helmets to integrate player head impact exposure and the risk of concussion. The Summation Test for the Analysis of Risk (STAR) relates on-field impact exposure to a series of drop tests performed at four impact location and six impact energy levels. The data from all drop tests are combined into one number using a complex formula. This new evaluation system is supposed to provide consumers with a meaningful metric to assess relative performance of football helmets.23
Concussion has different objectives in on-field assessment when the immediate safety of the athlete needs to be ensured and sideline assessment is needed to accurately determine what actions should be taken after the concussion occurs. The off-field/office assessment is required to determine the extent of the concussion and also to make the return to play decision. If physicians do not complete comprehensive assessments, they potentially could place athletes in dangerous situations. To ensure athletes' safety, established guidelines must be followed.25 Baseline measurements of subjective symptoms, balance testing, and neuropsychological testing should be obtained in high-risk contact/collision sports activity in the pre-participation physical exam. Managing a concussion can be challenging and requires a delicate balance between returning the player to sports as soon as possible and ensuring the athlete's safety. Clinicians should not be pressured by athletes, coaches, or teammates to return athletes to play too early.
Ankle Injury
Ankle sprains are the most frequent injuries sustained in sports and often lead to chronic pain, swelling, and functional instability. In the United States, there are approximately 2 million moderate-to-severe ankle sprains every year, which accounts for an estimated 14-33% of all sports-related injuries. Up to 40% of individuals who sustain acute ankle sprains have been found to have symptoms of chronic ankle instability and recurrent injury.26,27 These data suggest that considerable morbidity and unnecessary medical cost potentially may be averted with effective ankle injury prevention and treatment programs.26,28-32
In a review of 22 studies, Kerkhoffs et al found that functional treatment was preferable to immobilization for the initial treatment of acutely injured ankles.33 Rehabilitation can begin when the pain and swelling are under control. A review of clinical trials supports the use of NSAIDs in the early phase of ankle sprains (less than 2 weeks). Functional ankle rehabilitation starts by normal joint range of motion (ROM), followed by gentle stretching and progressive weight-bearing exercises. Resistance exercises can begin when there is no pain through the available ROM with full weight bearing.34
Proprioceptive exercises are an integral part of acute ankle sprain rehabilitation. Patients with functional ankle stability following an acute ankle sprain have been found to have a significant deficit in balance compared with the controls. Proprioceptive training using ankle disks/wobble boards has been shown to significantly improve balance testing and decrease the symptoms of functional instability.35-38
The use of ankle support and taping has been found helpful in preventing recurrent ankle injury. This benefit is related to enhancement of proprioceptive function of an injured ankle with taping or bracing. Following a review of 113 studies, Thacker et al recommended the use of ankle orthosis for 6 months after an athlete sustains moderate-to-severe ankle sprain.39-40
ACL Injury
Most ligament injuries are the result of excessive external forces applied to the limbs, while meniscus injuries are more likely secondary to torsional force generated within the limbs. However, anterior cruciate ligament (ACL) injury can occur without any application of external force to the knee joint. There are approximately 200,000 ACL and posterior cruciate ligament (PCL) injuries annually in the United States alone. Typically, an ACL injury is considered a season-ending injury for an athlete, with average recovery time and return to sports taking about 6 to 9 months. In addition, the psychological impact of such an injury can be tremendous.42
Multiple studies and randomized, controlled trials have shown the usefulness of an ACL injury prevention program among athletes. Female athletes have two- to 10-fold higher incidence of ACL injury compared with their male counterparts.43 The difference in anatomy — including greater Q angle, increased femoral anteversion, excessive tibial torsion, and excessive subtalar pronation compared with male equivalents — have been noted.44,45 In addition, women typically have a narrower A-shaped intercondylar notch compared with wider U-shaped notch in males of the same height and weight.46
Irrespective of various risk factors, injury prevention programs have been successful in reducing the risk of lower limb injuries, including ACL injury. Most of these programs have emphasized proper landing techniques, which includes landing softly on the fore foot and then rolling back on the rear foot, avoiding excessive genu valgum at the knees on landing and squatting, and engaging hip and knee flexion on landing and with lateral maneuvers. In addition, increasing strength and flexibility of hamstrings, gluteus medius, and hip abductors has been utilized in most ACL prevention protocols.43,47-53 The prophylactic use of a functional knee brace has not been able to demonstrate statistically significant injury reduction and is not currently recommended.42,54
Musculoskeletal Ultrasound
During the past 10 years, musculoskeletal ultrasound (MSKUS) has become a useful imaging, as well as an interventional modality in sports medicine. With the rapid development and sophistication of this modality, increased understanding of the pathophysiology of many disorders has been established. With increased utilization of MSKUS in sports medicine, it will be useful for emergency physicians to become familiar with the advantages and disadvantages of the MSKUS. Musculoskeletal ultrasound is invaluable for its ready availability, low cost, speed, and diagnostic accuracy. Musculoskeletal ultrasound also offers some specific advantages over MRI, such as higher resolution capabilities and the ability to examine the tissue in both static and dynamic states with the patient in different positions. MSKUS allows rapid real-time evaluation and also rapid comparison with the same structures on the contra-lateral side.55,56
Ultrasound is safe and free from ionizing radiation. In patients who have contraindications to use of MRI or MRI claustrophobia, ultrasound can be an attractive alternative, assuming the lesion is suitable for evaluation by ultrasound. In ultrasound machines with power Doppler capabilities, it allows for evaluation for "neovascularization" in tendinopathies.
One disadvantage of MSKUS is that it is operator-dependent and requires a long learning curve for competence in scan skills. MSKUS cannot penetrate the bones to any useful levels, but is very useful in the detection of bony erosions, calluses, and stress fractures. Artifacts are common pitfalls in the evaluation with MSKUS, with the most common being anisotropy.57
The shoulder is one of the most common applications of the MSKUS due to the high incidence of rotator cuff disorders related to increasing age and sporting activities. (See Figure 1.) Although the use of ultrasound is operator-dependent, in skilled hands and with appropriate equipment, this technique provides assessment of rotator cuff pathology with high sensitivity and specificity in the diagnosis of both partial and full-thickness tears.55,56
Figure 1: Long-Axis Views of Supraspinatus Tendon on MSKUS Showing Normal Tendon on the Left and a Significant Tear as Marked on the Right in a Different Patient
Interventional ultrasound refers to a wide and heterogeneous range of invasive procedures performed percutaneously using ultrasound guidance. Most of these procedures include aspiration of fluid from a joint or injection of medication either into a joint cavity, tendon sheath, or para-articular soft tissue.57
Platelet-rich Plasma Therapy
Platelet-rich plasma therapy (PRP), derived from the patient's own blood and injected into the area of injury (i.e., tendon, ligament, etc.), has been promoted as an option to treat both acute and chronic musculoskeletal problems and to promote healing. Most sports medicine physicians have to deal with situations when rapid recovery and early return to play is strongly desired by the athletes. Athletes may feel it affects their sports future, and in professional sports, it may translate directly into fame and money. PRP has been used as a treatment option with the objective of decreasing recovery time and facilitating earlier return to play.
Various growth factors are known for having tissue-healing properties. Early studies focused on purified isolated growth factors that have a role in tissue healing. It is now well known that to target various signaling pathways, there is a need to administer a balanced combination of mediators. Isolated growth factors likely would not be able to satisfy the multiple requirements of the injured tissue.
The clinical rationale behind PRP therapy is that the treatment contains many biologically active growth factors, including proteins responsible for homeostasis. These growth factors support regeneration of new connective tissue and also assist in revascularization. The higher concentration of cytokines and growth factors in PRP may act locally as regulators of most basic repair functions in acute and chronic injuries.58 Typical hematomas formed after acute muscle tear contain about 94% red blood cells (RBC) and 6% platelets. RBCs in general do not contribute to the healing process. The idea behind the PRP therapy is to reverse the RBC:platelet ratio from about 94% RBC and 6% platelets to 94% platelets and 6% RBC to stimulate recovery.59,60
The main growth factors in the PRP concentrate are the transforming growth factor-beta (TGF-beta), platelet-derived growth factor (PDGF), vascular endothelial factor, epithelial growth factor, hepatocyte growth factor, and insulin-like growth factor 1.58,60-62 Most of these growth factors play a role in muscle, ligament, cartilage, and bone healing by stimulating angiogenesis, epithelialization, cell differentiation, and formation of extracellular matrix.60-63 In particular, TGF-beta is one of the most important factors involved in cartilage regeneration.65,66 TGF-beta also counteracts with most of the suppressive effects of inflammatory mediators, including interleukin-1, on cartilage-specific macromolecules synthesis.59,67
Various in vitro and in vivo studies have been conducted to show the usefulness of PRP therapy after acute injury.59,65-74 In one study, after ultrasound-guided injections of platelet-released growth factors in 22 muscle injuries of 20 high-level professional athletes, full functional recovery was restored in as early as half of the expected time.75 Furthermore, fibrosis did not appear in any of the treated cases and no re-injuries occurred in any athletes after resuming their sports activities. There is a report of significant acceleration in functional recovery after surgical repair of ruptured Achilles tendons compared with a matched group who had conventional surgery.76 PRP therapy has been used to enhance the healing of meniscal defects67 and to stimulate chondrocytes63-66 to synthesize cartilaginous tissues in animal models.77,78 These results are intriguing, since both the avascular cartilage and meniscus have limited chances of proper functional repair.
PRP treatment is an option in athletes with chronic tendon injury. Positive effects of PRP on tendon healing have been documented in animal studies.62,79 Most of the human studies published on the use of PRP for the treatment of chronic tendon injuries are case studies. In a cohort study conducted by Mishra et al, there was a reported reduction in pain in patients treated with PRP therapy in cases of chronic severe lateral epicondylitis.80 Another small study using autologous blood injections followed by dry needling of tendon under ultrasound guidance suggested successful outcome in cases of refractory medial epicondylitis (golfer's elbow).81 Two studies have shown the benefit of PRP therapy in patellar tendinopathy.82,83
Cartilage injury is a significant part of morbidity of athletes and the general population. Studies are being conducted to see the results of PRP treatment in patients with cartilage injury and osteoarthritis. In vitro studies have shown the evidence of enhanced secretion of hyaluronic acid by synovial fibroblast from arthritic patients when exposed to preparations rich in platelet-released growth factors.84 In a pilot study of more than 100 patients with osteoarthritis treated with an intra-articular PRP injection, statistically significant improvement in pain and function were observed. In this study, mild pain reaction and minimal effusion after the injection were the most common side effects reported. The patients were followed up at 2, 6, and 12 months post-treatment. The positive beneficial effects of improved function and pain reduction were observed at 12 months follow-up, with a mean duration of beneficial effects lasting 9 months. However, the overall symptom reduction and quality of life at the 12-month follow-up continued to remain much higher than the baseline symptom evaluation conducted before the initiation of the therapy.85 The intra-articular injection of PRP has been compared with the intra-articular hyaluronan injection. This observational retrospective cohort study in patients with knee osteoarthritis showed better pain control and improvement in function in patients treated with PRP compared with hyaluronan injections.86
Overall, there is sufficient evidence from in vitro and animal studies to strongly suggest the usefulness of PRP therapy and its role in tissue regeneration and also in chronic tendinopathies. However, there is a lack of adequately powered studies and RCTs to substantiate the routine use of PRP therapy in humans.87 In general, the use of PRP appears to be safe with mixed results on the potential beneficial effects of PRP over traditional management.
Prolotherapy
Prolotherapy seeks to rehabilitate an incompetent structure by the generation of new collagen tissue accomplished by injecting a proliferant solution into the osseo-ligamenteous junction. The goal of most rehabilitative programs is to improve the performance of supporting musculature, but the ligament insufficiency and instability of the joint structures is ignored. Prolotherapy focuses on the rehabilitation of passive structures, including ligaments and tendons, with a goal to neutralize instability, correct the dysfunction of these structures, and, thus, alleviate pain.
The healing cascade is comprised of three stages:88-90
- Early inflammation when the tissue damage results in spillage of cell contents into the wound sites. The granulocytes debride the wound in this early stage.
- Late inflammation when macrophages and monophages secrete humoral factors to attract fibroblasts.
- Fibroblasts lay down new collagen fibers, adding strength to the wound.
After injury, connective tissue can return to its normal length, but it only regains 50-70% of its original strength.91 Weakened ligaments may result in instability and recurrent injuries in the affected area. Nociceptors in the ligaments have limited stretch capabilities, and any abnormal stretch of the ligament results in stretching of the pain receptors, culminating in pain response and muscle inhibition. This may result in exercise intolerance, which in turn may result in progressive weakening of the ligaments and instability. This perpetuates the vicious cycle and results in poor rehabilitative outcome. Any interruption in the healing process may lead to even poorer outcome.90,91
Solutions used for prolotherapy work by triggering inflammation and eventually fibroblastic proliferation. In one study, histological samples of tissue from the posterior sacroiliac joint ligament were taken 2 weeks before prolotherapy. Repeat samples were taken from the same ligament 3 months after the prolotherapy treatment. Comparison of these tissue samples by light microscopy revealed an increased number of total collagen fibers in 3 months post prolotherapy treatment compared with samples taken 2 weeks before the therapy.92
Different agents have been used for prolotherapy in the past, including a mixture of glucose, glycerine, and phenol. Currently, dextrose solution and sodium morrhuate are commonly used. Irritants like phenol and tannic acid work by causing local cell death, thus stimulating the healing process. Osmotics like glucose solution and glycerine or zinc sulfate dehydrate the tissue, thus causing local damage and inflammation.90 Since the first step in healing is inflammation, NSAIDs should be avoided in patients receiving prolotherapy.
The potential toxicity from injection of phenol has been analyzed. Phenol is produced in humans during the digestion of proteins and is rapidly metabolized by the liver to less-toxic substances. The concentration of naturally occurring phenol present in the urines of untreated patients is greater than the amount that might be injected during a prolotherapy session. Furthermore, phenol has a half-life of 1-4.5 hours and is completely eliminated from the body in 24 hours; therefore, there is little chance of chronic cumulative toxicity.93
However, prolotherapy injections are not without risk. Cases of death have been reported with inadvertent injection of zinc sulfate and phenol solution in the subarachnoid spaces, resulting in severe arachnoiditis and subsequent death.94 There have been two reported cases of sterile meningitis after inadvertent injection of a P2G (phenol, glucose, glycerine, lidocaine, and water) solution by accidently puncturing the dura while attempting to inject the interspinous ligament.95 Both of these cases resolved without complications. Several authors maintain that with proper technique and strict adherence to the appropriate injection procedure, the risk can be minimized.
Animal and human studies have shown evidence of beneficial effects with prolotherapy in various structural and ligamentous abnormalities, including mechanical low back pain,96-99 discogenic pain,91,98,100 osteitis pubis,99,101 foot problems,102 fibromyalgia,103 and overuse tendinopathies.104
Conclusion
With increasing athletic activity and increasing awareness of injury among the general public, more patients are likely to present to the emergency department for evaluation. It is important for the emergency physician to be up to date on concussion assessment. Knowledge about the long-term consequences of acute ankle and knee injuries will assist in providing appropriate discharge instructions and referrals for follow-up. Musculoskeletal ultrasound may be an option for evaluation of ligamentous injuries, such as around the shoulder. And patients may inquire about platelet-rich plasma therapy or prolotherapy after having read about it newspapers and magazines.
References
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