Incidence of Low Back Pain in Athletes and Differential Diagnosis and Evaluation of Athletes with Back or Leg Pain

Kenneth Nwosu, MD

Christopher M. Bono, MD

Dr. Bono or an immediate family member has received nonincome support (such as equipment or services), commercially derived honoraria, or other nonresearch–related funding (such as paid travel) from United HealthCare and Wolters Kluwer Health—Lippincott Williams & Wilkins; and serves as a board member, owner, officer, or committee member of AAOS, Journal of the American Academy of Orthopaedic Surgeons, and North American Spine Society. Neither Dr. Nwosu nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article.

Introduction

Low back pain (LBP) is nearly universal in the general population with a documented lifetime prevalence of 65% to 80%; 15% of the U.S. population reports frequent or persistent episodes.¹ The economic impact in this country has ranged from $84.1 to $624.8 billion annually.² Similarly, a high prevalence has been cited in other countries as well, with Biering-Sørensen and Hilden³ reporting that 405 to 60% of individuals aged 30 to 40 years in Denmark had a history of LBP. Considering the causes of LBP, frequent bending and twisting were the most frequent cause of back injuries in one study.⁴ Such movements are pervasive in most sports, and thus it is no surprise that low back injuries are exceedingly common in athletes. Sudden unexpected maximum efforts as well as lifting in combination with lateral bending and twisting are found to be particularly injurious.⁵ Overall, the static and dynamic forces exerted on the low back are exponentially magnified by the intense power generated during a golf or baseball swing, gymnast’s landing, power-lifter’s squat, boxer’s punch, cycler’s tuck, or a ballerina’s arabesque.⁶ In fact, LBP is the most common cause of lost playing time among professional athletes.⁷

In a discussion of LBP in athletes, it is important to delineate LBP as a symptom rather than a diagnosis, which may be influenced by many factors, including athleticism.⁶ In nonathletes, a variety of nonmechanical factors can predispose to LBP such as anxiety, depression, and stressful life events.⁸ Supportively, case-control studies have indicated that psychosocial factors are more influential than mechanical factors. In athletes, however, mechanical factors are more often implicated because they are modifiable via technique and training alterations. Furthermore, athletes, particularly those at the professional or competitive level, have a strong drive and vested interest in returning to play despite pain. Notwithstanding, the psychological and emotional burden of LBP in athletes should not be overlooked or underestimated.

Incidence

The published prevalence of LBP in athletes widely ranges, being influenced heavily by sports type; gender; and training intensity, frequency, and technique.⁹^,¹⁰^,¹¹ Observing a 10-year period of time, Keene et al reported that 7% of 4790 varsity college athletes had LBP,¹² with
rates highest in football players, gymnasts, and wrestlers. Diagnosis of acute muscle strain occurred most frequently (59%) compared with overuse injuries (2%), which were the least common.

Influence of Sports Type

From review of a variety of studies, it appears that the incidence of LBP is not equivalent among all sports and athletes. Among athletes participating in a variety of sports, Keene and Drummond found the highest incidence of LBP in football players, gymnasts, and wrestlers.¹³ Granhed and Morelli¹¹ found a higher prevalence of LBP in wrestlers (59%) compared with weight lifters (23%) and a control population (31%). There is a common perception that running, because of the repetitive axial loading, can be injurious to the lumbar spine. In reality, the incidence of LBP in runners is comparatively low, ranging from 1.1% to 22.5%.¹⁴ Furthermore, runners do not have a higher prevalence of radiographic degenerative changes than nonrunners.¹⁵

Ferguson et al¹⁶ reported a high incidence of LBP in collegiate interior linemen, citing that 50% sought consultation for this complaint during a 1-year period. Of these, half were found to have spondylolysis, and 16.5% had spondylolisthesis. This group postulated that this was likely the result of repetitive posterior element loading during tackles. Others sports that require repeated hyperextension, such as gymnastics, diving, and volleyball, may be associated with a high incidence of LBP.¹⁷ Rossi et al¹⁴ documented 32% and 63% incidences of spondylolysis among competitive gymnasts and divers, respectively.

Hyperextension is not the only mechanism by which LBP is thought to develop. High rates of LBP have also been commonly reported with sports requiring repetitive rotation of the torso such as tennis, badminton, squash, and golf. Spencer and Jackson et al¹⁸ found that 90% of tournament golfers have had back injuries. Specifically, in professional golfers, Tall and Devault et al¹⁹ reported a 29% incidence of LBP.

Although LBP is quite prevalent in athletes while competing, it does not seem to be a permanent complaint despite longstanding radiographic changes. For example, in a study of former athletes, wrestlers had a high prevalence of old, healed fractures, and weight lifters had substantially decreased intervertebral disk heights. However, none of the wrestlers and only 5% of the weight lifters reported that they were disturbed by LBP during work compared with 70% of nonathlete control participants.¹¹

Low Back Pain with Associated Leg Pain

In both athletes and nonathletes, LBP often concomitantly presents with radicular leg pain. Because it can be a part of the degenerative cascade, disk herniations can lead to lumbar root compression and irritation. The prevalence of LBP with associated leg pain (LBPLP) in the general population has varied from 1.2% to 43%.²⁰ The literature is sparse regarding the prevalence of LBPLP in athletes. One study reported a 58% prevalence of one or more disk herniations in Olympic athletes with LBP, some of whom had leg pain.²¹ Of note, the L5 to S1 disk was most commonly affected in this study.

Although not helpful in estimating incidence or prevalence, recent reports of treatment outcomes in athletes with lumbar disk herniations and associated leg pain implicitly support that it occurs with at least some frequency.²² Furthermore, Hsu et al reported that perception of a positive outcome in athletes may be different than nonathletes.²² This group found that age was a negative predictor of career length, and experience was a positive predictor of clinical outcome in athletes with disk herniations and LBPLP. Of note, National Football League (NFL) athletes were more likely to have a positive outcome compared with those in other sports when treated surgically.²²

Evaluation

History

Evaluation of athletes with LBP begins with a thorough history. The onset and duration of symptoms must be noted. Whereas sudden onset of acute symptoms can suggest an acute fracture or disk herniation, a slow, indolent presentation is more consistent with pain from disk degeneration, spondylolysis, or stress fracture. The location of pain is an important feature to note. Pain that is localized to one midline point without radiation is consistent with dysfunction of a single motion segment. Symptoms that diffusely involve multiple levels are more suggestive of muscular pain. Directionality of pain provocation can be helpful in distinguishing disk-related pain, which is aggravated by bending forward, and posterior element pain (e.g., pars interarticularis or facet joints), which is worsened with extension and often relieved with flexion. The type of sport, position played, and volume of training should be recorded because these can be factors in the onset of LBP. So-called red flag symptoms such as
fever, malaise, weight loss, neurologic abnormalities, or night pain can indicate serious conditions such as infection or tumor that require more aggressive diagnostic imaging workup.

FIGURE 16-1 Clinical photographs of normal static coronal (A) and sagittal (B) posture.

Physical Examination

Athletes often develop side-to-side musculoskeletal asymmetry. The spinal column is no exception. Thus, gait and static posture should be observed for abnormalities (Figure 16-1). Posterior inspection should note the presence of shoulder, trunk, or pelvic asymmetry. Lateral inspection should confirm normal spinal curvature, including moderate lumbar lordosis without thoracic hyperkyphosis.

Next, the athlete should be observed flexing, extending, and rotating through the lumbar spine. Importantly, the pelvis should be kept fixed during rotation so as to isolate movement to the lumbar spine. Distinction should be made between painless limitation of motion, which suggests loss of flexibility, and painful motion, indicating that the motion is loading a pain generator.

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