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A Nontraumatic Clay Shoveler's Fracture in a Runner

2021; Lippincott Williams & Wilkins; Volume: 20; Issue: 1 Linguagem: Inglês

10.1249/jsr.0000000000000794

1537-8918

Ryan Sorell, Kyle Wieschhaus, Stephen M. Simons,

Winter Sports Injuries and Performance

Background Lower cervical or upper thoracic spinous process avulsion fractures are commonly known as a "clay shoveler's fracture" named for the frequent injury seen in early 20th century Australian road construction workers (1). This fracture pattern has not been reported as a runner injury. A thorough literature review yielded only a few case reports of clay shoveler's fracture occurring in nontraumatic settings. Osteoporosis secondary to the female athlete triad may have been a critical predisposing risk factor for this rare fracture. The female athlete triad is defined as a medical condition often observed in physically active girls and women and involves three components: 1) low-energy availability with or without disordered eating, 2) menstrual dysfunction, and 3) low bone mineral density. Female athletes often present with one or more of the three triad components, and early intervention is essential to prevent its progression to serious end points that include clinical eating disorders, amenorrhea, and osteoporosis (2). The female athlete triad has been further elaborated with the more recent concept of Relative Energy Deficiency in Sport (RED-S). RED-S refers to impaired physiological functioning caused by relative energy deficiency and includes, but is not limited to, impairments of metabolic rate, menstrual function, bone health, immunity, protein synthesis, and cardiovascular health (3). Low-energy availability (LEA), the etiologic requirement of RED-S, is a mismatch between an athlete's energy intake (diet) and the energy expended in exercise, leaving inadequate energy to support the functions required by the body to maintain optimal health and performance, leading to numerous adverse physiologic consequences. There are known impairments of metabolic rate, menstrual function, bone health, immunity, protein synthesis, and cardiovascular health (3). Research regarding these syndromes has helped increase understanding of not only how and why these abnormalities occur but also how to evaluate for and treat to optimize the health of the female athlete. Case Presentation History An 18-year-old female National Collegiate Athletic Association (NCAA) Division 1 cross-country athlete presented to the training room with a chief complaint of neck pain. Symptom onset occurred 3 d earlier upon completing a swim workout. She described the pain as sharp and centrally located in her lower neck and upper back. She denied radiating pain or associated neurologic deficits. She did not recall any sentinel event that triggered her pain. She did note that she "did not feel right" while performing a biceps curl to overhead press during a weight training session 3 d prior to the swim. She attributed this odd feeling to poor form or excessive weight effort. History was unremarkable for musculoskeletal injury. Examination Body mass index (BMI) was 18.9 kg·m2, and vitals were normal. Focused examination: neck range of motion was limited by midline lower cervical pain. Tenderness to moderate direct palpation over C7 to T2 spinous processes was noted. Upper-extremity neurologic examination was normal. There was no focused shoulder examination. Absent a traumatic origin, a soft tissue muscle source for the pain was presumed. Initial management included a recommended few days rest from aggravating activity. Symptoms did not improve after one further week of rest. Imaging Cervical and thoracic spine X-rays demonstrated a T1 avulsion fracture. A computed tomography (CT) was obtained to assess for additional injury (Fig.). The CT confirmed only the T1 avulsion fracture — displaced approximately 50%.Figure: Sagittal CT of T1 clay shovelers fracture.An atraumatic fracture and no previous fracture or stress fracture history without apparent cause prompted further history for contributing factors. A menstrual history revealed menarche at age 14 years with continuing oligomenorrhea to present day. She alternated between regular periods (every 28 d) when out of season, with less consistent or absent menstruation in the fall and spring when competing. Her last menstrual period was 4 months prior to presentation. Using criteria set forth by De Souza et al. (2) in the Female Athlete Triad Coalition Consensus, a dual-energy X-ray absorptiometry (DXA) scan was indicated. This was based on the patient's vertebral fracture as a low-energy nontraumatic fracture coupled with her history of secondary oligomenorrhea. The DXA Z-score for the lumbar spine was −3.3. The left and right femoral neck scores were −1.4 and −0.3, respectively. The patient's age of 18 years was below the calculation level of the DXA software. For the purpose of obtaining the data, the patient's age was advanced to 20 years. The numbers were then placed into a bone mineral density calculator to obtain the true estimate of the Z score. The Z score calculated for an 18-year-old was not significantly different than the machine calculated score for a 20-year-old. Preseason laboratories, obtained just 3 wk prior to presentation included a ferritin, 45 ng/mL; hemoglobin, 13.5 gm/dl; vitamin D, 13.5 ng/ml. No further laboratory tests were obtained. Assessment Final diagnosis was cervical spine avulsion fracture, "clay shoveler's fracture," in the setting of female athlete triad and severe osteoporosis. The patient was an identical twin. Her twin, also recruited to NCAA Division 1 track and cross-country, had similar menstrual history without stress fracture history. The sister did suffer a traumatic fracture of the wrist from a bicycle accident. Her BMI was noted to be 17.9 kg·m2. The twin was advised to undergo DXA testing. Her DXA Z-scores were −4.3, −1.9, and −1.5 for the lumbar spine, left and right femoral necks respectively. The patient was managed with further rest, as needed use of a soft cervical collar, and oral analgesics. Both the injured athlete and her sister were initiated on transdermal estrogen with cyclic progesterone and provided with nutrition counseling. The patient's pain gradually subsided. She used an exercise bicycle and gradually advanced to running first using a gravitational assisted treadmill. During this period, her nutrition also was closely monitored to ensure correction and prevention of LEA. Discussion This is the first reported case of a clay shoveler's fracture in a collegiate runner. Although the precise mechanism of injury remains uncertain, an overuse fracture of insufficient bone is plausible. A clay shoveler's fracture was known historically as an occupational hazard of manual laborers whose job entailed shoveling, metal dipping, land grading, tree removal, and road construction. The incidence of this type of fracture subsided as modern machinery replaced the need for such repetitive physically demanding work. Now, cases are reported in various sports, including rock climbing, power lifting, volleyball, American football, amateur golf, baseball, wrestling, and kayak paddling (4,5). These cases suggest repetitive rotational movement patterns that cause bone failure. Two mechanisms are suggested. An acute (abrupt symptom onset) type suffered by the individual introducing a novel activity or movement pattern and the acute-on-chronic type noted in high-intensity athletes. The latter experience prodromal neck/upper back pain before the eventual fracture occurs. Our case presents both a never before described clay shoveler's fracture in a runner and a possible third contributing mechanism of insufficiency fracture from osteoporotic bone. Since this athlete experienced pain immediately following a swim workout and 3 d following a weight lifting workout, it is unclear if these activities solely, or in combination with running, contributed to the fracture. The previously reported athletic clay shoveler's fractures are most likely fatigue fractures. Our present case could be a fatigue fracture, but more likely represents an insufficiency fracture (6). The female athlete triad should be considered when an elite female athlete presents with an unusual injury to bone. This condition is widely accepted as LEA, menstrual dysfunction, and low bone mineral density that predisposes to bone stress injury (7). Of elite female athletes, those with low BMIs, oligmenorrhea/amenorrhea, and participation in low-impact sports are at even greater risk of falling victim to this pathology (7–10). RED-S is a syndrome of impaired physiology functioning in the setting of LEA. RED-S can cause multiple physiologic consequences including low bone mineral density, a critical component of the female athlete triad (3). Trabecular bone, as the vertebral spine in the present case, compromised by low bone mineral density, is particularly vulnerable to overuse stress fractures (11,12). Bone mineral density testing with DXA scans should be considered in athletes presenting with components of the female athlete triad. Testing is indicated if any one of the "high-risk" triad risk factors is present, including history of an eating disorder, low BMI (≤17.5 kg·m2), delayed menarche beyond age 15, current amenorrhea, two prior stress fractures, or a single high-risk stress reaction/fracture. DXA testing also may be indicated for individuals suffering from multiple "moderate" risk factors. Consensus statements highlight the importance of recognition, prevention, and treatment (2,3). The guidelines recommend nonpharmacologic management, specifically modification of exercise and nutrition, to correct the state of LEA. Nutritionists, physiologists, as well as mental health professionals, are an integral part of the team (2,3). As recent as 2019, the International Association of Athletics Federations recommended intensive monitoring of not only intake of calories, carbohydrates, and fluids in a food-first manner, but recognizing that timing and supplementation also are key to maintaining adequate energy availability (13). Treatment with hormonal therapy may be indicated once decreased bone mineral density has occurred, and there is no improvement after 12 months of nonpharmacologic interventions. An individualized structured return to participation plan may be just as critical to preventing reinjury of the athlete (3). The athlete and her family were quite alarmed and concerned about the markedly low bone density and the probable consequent fracture. Her twin was equally surprised and concerned. Given the test results, the desire to return to athletics and to moderate future fracture risk, the athletes and their parents elected to forego the recommended 12 month trial of nonpharmacologic therapy. The patient and her sister were both prescribed continuous transdermal estrogen (physiologic 17B-E2) with cyclic progesterone. Transdermal estrogen is superior at improving bone density than combined oral contraceptives and nonpharmacologic interventions alone (14). This therapy is recommended for athletes' aged 16 to 21 years with decreased bone mineral density and triad risk factors to minimize further bone loss in this critical period (15). This presentation is made more intriguing by the confluence of circumstances occurring in twins. Similar bone pathology, one injured and the other never injured. At the time of this submission, the sentinel case, twin A, has suffered three more stress fractures, whereas her twin sister remains injury free while at the same time performing at a very high level. Existing literature contains only a single case study of monozygotic teen athletes suffering from the female athlete triad. That case highlighted the difficulty in treating this syndrome and noted lack of structured support as an aspect that may have contributed to this (16). There are multiple studies using twins to investigate genetic influence to overall bone health (16–21), response to nutrition and exercise (22,23), and possible diagnostic and therapeutic targets (24). Currently, the vast majority of these twin studies have focused on perimenopausal and postmenopausal women. Additional twin research has studied the effects of energy intake on weight, performance, and metabolic/hormonal responses (25–27). These studies suggest genetic influences, but unfortunately, thus far, only male athletes have been studied. There is a current literature gap regarding twin female athletes experiencing the female athlete triad and the attendant bone health concerns. Conclusions A nontraumatic cervical spine avulsion fracture; "clay shoveler's" fracture has not been reported in a runner. This fracture usually occurs as an acute injury from sudden traction force or result from repetitive overload as a stress fracture. Although the weight-lifting incident is suspect, the proximate cause of the fracture remains a mystery. The female athlete triad and consequent osteoporosis probably contributed to this unusual fracture. Several fractures are known as "high-risk" stress fractures attributed to the female athlete triad. This particular fracture has not been described in this context. As had been suggested in prior case studies, a clay shoveler's fracture is managed nonoperatively. Most heal as a fracture nonunion. Surgical resection is reserved for relentless pain. Additionally, in this case, it also was important to address the potential contribution of osteoporosis and the patient's LEA with hormone therapy and nutritional support.