OVERUSE INJURIES IN ATHLETICS CLINICAL APPROACH TO COMMON & STRESS FRACTURES IN ATHLETICS

– Written by Thomas P.A. Baltes, Ken Van Alsenoy and Pieter D'Hooghe, Qatar

INTRODUCTION gender1. In athletics stress fractures are risk factor contributes to the occurrence of Stress fractures are a common injury typically observed in the female long- insufficiency-type stress fractures, that may in sports (1.54 - 5.70 per 100 000 Athlete distance runners. In these athletes the occur, even in response to normal strain3. The Exposures)1. Elite Track and Field athletes repetitive load and impact absorbed by the location of stress fractures varies between have been shown to be particularly foot and ankle can cause distinct micro- sports, however stress fractures of the foot susceptible to this kind of injury, presenting fractures and abnormal remodelling. and ankle are most frequently observed in with the highest frequency of bone-stress When left untreated this process can the , followed by stress fractures of the injuries in both the 2012 London Olympics progress to form a fatigue-type stress metatarsals, and navicular bone1,2. and 2016 Rio Olympics2. With the seventeenth fracture3. Female athletes are at increased The importance of a multidisciplinary edition of the IAAF World Championships to risk of stress fractures in comparison to medical support team in elite sports is be held in Qatar this September, the medical their male counterparts as part of the well established. This is particularly true staff at Aspetar Orthopaedic and Sports Relative Energy Deficiency in Sport (RED-S) in the management of bone stress injuries, Medicine Hospital are preparing to deliver syndrome; a relative energy deficiency which can potentially be diagnosed in care to the participating athletes who are at impairing physiological functions, including the prodromal stage. If diagnosed early, increased risk for this type of injury. metabolic rate, menstrual function and progressive load management with The incidence and location of stress bone health4,5. In female athletes, and to a additional conservative measures (e.g. fractures varies between sports and among lesser extent in male athletes, this unique cushioned footwear; foot orthotics and

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Figure 1: Tibial of the anterior cortex. (a) Conventional sagittal radiograph showing endosteal thickening, periosteal reaction and an incomplete fracture line through the anterior tibial cortex (b) Coronal T2-weighted image demonstrating periosteal and bone marrow edema. Figure 2: Proximal IV metatarsal stress reaction; Long-axis T2-weighted image demonstrating extensive bone marrow edema of the distal metatarsal IV and surrounding soft-tissue edema. Figure 3: Stress fracture of the distal fibula. (a) Conventional coronal radiograph demonstrating periosteal reaction and endosteal sclerosis (b) Coronal T2-weighted image showing diffuse bone marrow edema and a discrete fracture line. Figure 4: Navicular stress fracture (a) Coronal and (b) Axial T2-weighted images demonstrating bone marrow edema and a clear fracture of the navicular bone (modified Saxena type 3). vitamin D and Calcium supplementation) medical support team to adequately answer TIBIAL STRESS FRACTURES may help to prevent bone stress injuries this question, it is important to understand Tibial stress fractures are the most evolving into stress fractures, reducing that treatment should be tailored to the common lower extremity stress fractures time lost from participation6,7. However, the healing propensity of the stress fracture. among active individuals (e.g. military clinical presentation of stress injuries is not Stress fractures are therefore classified recruits and athletes). Most commonly, tibial always clear cut and stress fractures may as low-risk or high-risk, depending on stress fractures occur at the posteromedial occur despite preventative measures by the their healing propensity (Table 1). Based cortex as a result of forces experienced medical and coaching teams. on available evidence we will discuss during walking and running8. These forces When faced with the adversity of a the diagnosis, management options and are hypothesized to be a combination of stress fracture, the main concern of athletes prognosis of (1) Tibial, (2) Metatarsal (3) impaction forces and muscular forces of is: ‘What treatment option will allow me Fibular and (4) Navicular stress fractures the gastrocnemius-soleus complex and to return to sport (RTS) quickest?’. For the (Figures 1-4). deep plantar flexors9. A less common (but

SPORTS MEDICINE AND SCIENCE IN ATHLETICS TARGETED TOPIC 281 OVERUSE INJURIES IN ATHLETICS

significantly more devastating) entity is Table 1 the anterior tibial cortex stress fracture. In contrast to posteromedial cortex fractures, they result from forces experienced during jumping.10 Anterior tibial cortex fractures High Risk Low Risk are considered high-risk stress injuries as they carry significant risk of complete Fifth metatarsal Medial tibia fracture and non-union11. Symptoms of tibial stress fractures Anterior tibia Metatarsals I-IV include pain induced by exercise, point tenderness and swelling over the tibial Navicular shaft. However, classic symptoms might be absent in some patients. The diagnostic Medial work-up of tibial stress fractures is Table 1: Classification of stress fractures according to healing propensity. initiated with conventional imaging. However, radiographic findings may lag behind clinical symptoms by 2-3 weeks, often rendering conventional Table 2 imaging insensitive12. Radiographs may demonstrate decreased cortical density, Grade 0 No abnormality periosteal reaction, endosteal thickening and intramedullary sclerosis. A discrete Periosteal edema with no associated bone marrow signal Grade 1 fracture line is a late finding. In case of abnormalities. negative radiographs, but high clinical Periosteal edema and bone marrow edema visible only on T2- Grade 2 suspicion, Magnetic Resonance Imaging weighted images. (MRI) is the preferred imaging technique. Periosteal edema and bone marrow edema visible on both T1 and MRI might be used to confirm the diagnosis Grade 3 T2 weighted images. and classify the severity of the bone stress injury according the modified Fredericson Multiple focal areas of intracortical signal abnormality and bone classification13. (Table 1) Grade 4A marrow edema visible on both T1-weighted and T2-weighted Treatment of posteromedial tibial images. fractures is primarily conservative as they Linear areas of intracortical signal abnormality and bone marrow Grade 4B have a high propensity to heal. Conservative edema visible on both T1 and T2 weighted images. rehabilitation is focused on activity Table 2: (Modified) Fredericson classification for tibial stress fractures (Kijowski R et al. 2012 modification with continued weight- Am J Roentgenol). bearing as tolerated 14. After the patient has been able to bear weight pain-free for two weeks, progressive return to full impact Table 3 activities can be initiated. Non-steroidal anti-inflammatory drugs (NSAIDs) should be avoided as they may hamper bone Stress reaction; signal change on MRI noted, but stress fracture Type 0.5 healing15. In contrast, anterior tibial cortex not imaged on CT stress fractures are considered high risk as Type 1* Fracture of dorsal cortex they are associated with high rates of non- union and complete fracture11. This can be Type 2* Fracture of dorsal cortex into navicular body contributed to poor vascularity, absence of musculotendinous support and structural Type 3* Complete propagation through both cortices tension on the anterior cortex. Conservative treatment of these fractures often is often Table 3: (Modified) Saxena Classification for Navicular stress fractures. unsatisfactory, with high rates of non-union and low percentages of return to sport16. However, randomized trials comparing injuries. Anterior tibial stress fractures secondary tension band plating, making it conservative treatment versus primary were found to be able to return to sport an interesting option in selected patients16. surgical intervention are lacking. at 24 weeks after conservative treatment. The prognosis of tibial stress injuries However, if conservative treatment failed METATARSAL STRESS FRACTURES depends on their severity13, ranging (53%), return to play was 28.4 weeks after Metatarsal stress fractures are the from a mean time of 16 days for grade 1 subsequent surgery11. Small case series have second most common stress fracture of injuries to a mean 71 days for grade 4b demonstrated quicker return to play with the foot and ankle. They are typically seen

282 athletics is lacking. In football players return to play times after a fifth metatarsal (stress) fractures were found not to differ between conservative and surgical treatment (74 days vs. 80 days) if consolidation occurred (33% vs. 75%)27. However, conservative treatment is often related to healing problems, delaying return to play. In professional soccer players mean return to play after intramedullary fixation of fifth metatarsal stress fractures was established to be 10.5 weeks25.

FIBULA STRESS FRACTURES Fibula stress fractures are rare but should be considered in the long-distance running and track and field athlete. They account for 4.6% to 21% of all stress fractures and are the most common within 4 to 7cm from the distal tip of the lateral malleolus28. They are considered low risk as the fibula only bears 10% of the load during activity and the risk of displacement is minimal29,30. The cause of fibular stress fractures is attributed to an increased traction and torsional force from the plantar flexors and peroneal muscles (e.g. during excessive pronation or supination). This mechanism is hypothesized to overload the lateral compartment increasing stress on the fibular structure31. Symptoms, like most stress fractures, in military personal performing marches fracture typically demonstrate linear start vague and are often described as (hence, march fractures). Stress fractures sclerosis perpendicular to the direction of persistent pain or tenderness over the most frequently affect the diaphysis and stress20. MRI findings include intramedullary fibula, with occasionally referred knee distal part of metatarsal III. This can be edema, periosteal edema and a fracture line pain. Symptoms are often aggravated with attributed to the low bending stiffness in severe cases. Various classifications have activity such as running and jumping14,29. of this metatarsal, due to its ligamentous been proposed to describe fifth metatarsal Standard radiographic changes consist of support17. Most stress fractures of metatarsal stress fractures 18,21,22. However, the Torg a sclerotic or radiolucent line at the level I-IV are considered low risk as they possess classification is the most commonly used23. of lateral malleolus but can be negative a high healing propensity. Metatarsal (Table 2). in up to 40% of cases32. Early stage MRI is V stress fracture typically involve the Treatment of metatarsal II-IV stress recommended, as it will be able to pick up diaphysis and should be differentiated fractures consists of activity modification periosteal reaction and fibular bone marrow from the more proximal traumatic avulsion and continued weight bearing, as they edema33. fractures. They are hypothesized to result possess a high healing propensity. Surgical Most athletes can be treated from forces experienced as the result treatment is reserved for those cases with conservatively as the fibula is a non- of bone morphology, cavus foot type or dorsiflexion of fracture fragments or in weightbearing osseous structure30. inappropriate foot wear18. Metatarsal V case of non-union (high tendency in base of Conservative treatment consists of fractures are classified as high-risk stress metatarsal II)8. In elite athletes, metatarsal V immobilisation with a non-weightbearing fractures as they often result in non-union stress fractures are advocated to be treated walker or removable cast for 2-6 weeks as a result of poor vascular supply19. surgically, as conservative treatment may followed by a gradual return to activity and Symptoms of metatarsal stress fractures result in increased risk of non-union and sports, as symptoms allow. Contributing include dull ache or pain at the base of may delay return to sport24. Fracture fixation biomechanical factors of foot and ankle such the affected metatarsal during weight using a single intramedullary screw is the as excessive pronation/supination should bearing exercise, often coinciding with current standard of care25. be addressed accordingly with footwear increase of training intensity or training Return to sport in Track and Field athletes and, where necessary, foot orthotics. volume. In case of a metatarsal II-IV stress for conservatively managed metatarsal II-IV Athletes with this type of stress fracture fracture, radiographs typically demonstrate fractures is a mean 11.7 weeks26. However, will take about 13 weeks to return to sport, periosteal reaction and cortical lucency. this outcome is based on a small case series however, some advocate a quicker return to Radiographs of first metatarsal stress of ten patients as return to play data in sport under the provision that the athlete is

SPORTS MEDICINE AND SCIENCE IN ATHLETICS TARGETED TOPIC 283 OVERUSE INJURIES IN ATHLETICS

conservatively. A subset of patients with anterior tibial stress fractures might benefit from surgical treatment, A multi-disciplinary however, high quality evidence is lacking. approach by the coaching 2. Stress fractures of metatarsal II-IV have a good healing tendency; Metatarsal staff and medical support V stress fractures should usually be treated surgically due to risk of non- union. team is essential to diagnose 3. Conservative treatment seems suitable for most uncomplicated fibula stress bone stress injuries and fractures, however, faster return to sports might be possible with surgical minimize injury time loss. management in elite athletes. 4. Stress fractures of the navicular bone are considered high risk and are often treated surgically. pain free while using a brace during sport bone stress injuries. Bone stress injuries of activities and is monitored closely32. In the the navicular are classified using the Saxena event of a delayed union, prolonged casting classification36,37. References can be considered. Non-unions often require Conservative treatment may be Available at www.aspetar.com/journal surgical intervention, however, literature on considered if the navicular stress injury is treatment of these injuries is lacking. 31. diagnosed in an early stage (Saxena Type 0.5). Conservative treatment consists of NAVICULAR FRACTURES immobilization and non-weight bearing Navicular stress fractures represent 14%- for 1-3 weeks until tenderness on palpation Thomas P.A. Baltes M.D. 25% of all stress fractures. In contrast to most of the N-spot is absent38. The subsequent Post Graduate Researcher stress fractures, they are predominantly in progressive loading programme may take male athletes (e.g. hurdling, jumping).8 The up to 4-6 months34. However, in case of a Aspetar Orthopaedic and Sports Medicine Hospital middle third of the navicular bone is the delayed or non-union, a more aggressive most frequently affected area. It is relatively approach by open reduction internal Doha, Qatar avascular, with a negative impact on fixation (ORIF) should be applied. For the 34 healing. The navicular bone is important elite athlete, surgical treatment is preferred Department of Orthopaedic Surgery for stability of the medial longitudinal arch as it minimises the risk of non-union and Amsterdam UMC, University of 34 and is subjected to high compression forces ensures a clear RTS timeframe . Amsterdam, Amsterdam Movement during the propulsive phase of gait. A cavus Return to sports outcome data after Sciences foot type, reduced ankle dorsiflexion and treatment of navicular stress fractures Amsterdam, The Netherlands an index-minus morphotype all amplify is scarce. The average return to sport compression loading in the navicular, after conservative treatment has been increasing the risk of a bone stress reaction35. reported to be > 6 months. Return to sport Academic Center for Evidence-based Navicular stress fractures are classified as after a surgical treatment of type 2 and 3 Sports Medicine (ACES), Amsterdam UMC, Amsterdam Movement Sciences, high-risk stress fractures due to limited navicular stress fractures averaged 4.2 (±1.5) vascularity14. months36,38. Amsterdam, The Netherlands Symptoms of navicular stress fractures include dull pain over the medio-dorsal CONCLUSION Ken Van Alsenoy M.Sc. aspect of the foot and palpation tenderness A multi-disciplinary approach by the Podiatrist over the navicular bone, (N-Spot). Clinically, coaching staff and medical support team is symptoms can be aggravated by functional essential to diagnose bone stress injuries in tests (e.g. single leg hopping, tip-toe the prodromal stage and minimize injury Pieter D'Hooghe M.D. walking). Most navicular stress fractures time loss. If diagnosed early, progressive load Chief of Surgery do not involve the plantar cortex, making management with additional conservative them difficult to identify on radiographs34. measures can prevent progression of bone Aspetar Orthopaedic and Sports Medicine Plain radiographs may show a sclerotic stress injuries. Management of stress Hospital or radiolucent line extending from the fractures should be tailored to the healing Doha, Qatar superior tension side of the navicular bone, propensity of the stress fracture. but it often lacks sensitivity28. MRI is the 1. Most stress fractures of the gold standard for diagnosing navicular posterior tibial cortex can be treated Contact: [email protected]

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