Emily Bolthouse, DPT, CSCS1 Return to Running After a Allison Hunt, DPT, CSCS1 Karen Mandrachia, DPT, CSCS1 Tibial Stress Fracture: Lauren Monarski, DPT1 A Suggested Protocol Krishinda Lee, DPT, CPT1 Faculty Mentor: JK Loudon, PT, PhD, SCS, ATC, CSCS2 1Doctor of Physical Therapy Student at time of submission, Doctor of Physical Therapy Division, Department of Community and Family Medicine, Duke University School of Medicine, Durham, NC 2Associate Professor, Physical Therapy Education, Rockhurst University, Kansas City, MO ABSTRACT given year. Further, a higher incidence of order to identify potential injury-causing Background and Purpose: Typical injury has been appreciated in runners with factors. A sudden increase in the intensity treatment of tibial stress fractures requires previous lower extremity pathology.1 and duration of training puts the runner at cessation of weight bearing activity followed One overuse running injury that com- risk for developing a stress fracture.7 A study by a gradual return to running. The purpose monly plagues both elite and recreational by Matheson et al8 states approximately of this review was to examine the evidence athletes is a stress fracture. Stress fractures 30% of athletes who had stress fractures behind increasing running mileage by 10% account for 15% to 20% of overuse injuries incurred the injury within 12 weeks of a per week and develop an evidence-based in runners.2 A stress fracture is a mechanical change in training regimen. The mileage run return to running program. Methods: A failure of the bone in which activity of the per week can also be a factor in the occur- literature search was conducted using search osteoblasts cannot keep pace with activity of rence of stress injuries. Higher mileage per terms related to running, stress fractures, the osteoclasts. A repetitive, cyclical loading week is associated with increased risk of and bone healing. Relevant articles were of the bone with inadequate recovery tran- overuse injuries.7 Studies show that running identified through a 3-stage study selection spires and the bone is unable to repair itself more than 64 km/week (approximately 40 process. Findings: The search produced 15 between exercise sessions.3 Unfortunately, miles/week) is a significant risk factor for articles. One article contained a randomized the repetitive and high loading nature of run- lower extremity injuries.9 Likewise, limited controlled trial examining a graded training ning creates an ideal environment for stress evidence suggests running year round with- program. Eight articles contained return to fracture development. Other factors such as out a break from training is a significant risk running protocols. Clinical Relevance: This an increase in training intensity, running on factor for lower extremity injuries.1 article provides an evidence-based protocol hard surfaces, inappropriate footwear, and Other changes in training regimen such encompassing the most important aspects poor biomechanics may contribute as well.4 as changes in running surfaces or footwear of stress fracture management. Conclusion: The tibia is reported to be the most common are associated with injury as well.3 Both An original source or evidence for use of site of stress fracture occurrence, accounting Ballas et al7 and Taube et al10 suggest run- the 10% guideline was not found. Several for 35% to 56% of all stress fracture inju- ning on hard surfaces consistently (such as articles suggested protocols or evidence for ries.5 Tibial stress fractures in runners are concrete) may increase the risk of stress frac- certain aspects of treatment, but none pro- most commonly located at the junction tures. Conversely, van Gent and colleagues1 vided a complete evidence-based guideline of the middle and distal thirds of the tibia suggest the evidence behind this association or treatment plan. along the tibial shaft.6 is limited. Although some studies show foot- wear can play a preventative role in stress Key Words: bone, injury, rehabilitation, Etiology of Injury and Risk Factors injuries overall, it may not play a significant sport A number of extrinsic and intrinsic ele- role in the reduction of tibial stress fractures ments are considered risk factors for tibial specifically.11 Some evidence suggests that INTRODUCTION AND stress fractures. An extrinsic element is an proper footwear may be a protective factor BACKGROUND external factor that can impose additional for female runners only.1 Long distance running is a commonly stresses on the bone while running. Exam- Inappropriate running mechanics are practiced means of engaging in exercise, ples include training regimens, footwear, common intrinsic factors associated with physical activity, and leisure among the and running surfaces. An intrinsic element stress factors. Specifically detrimental are general population. Easy accessibility and is an internal factor that can impose addi- running mechanics such as deviations in a growing interest in disease prevention tional stresses to the bone. Examples of hip and ankle motions that increase tensile contribute to its increasing popularity.1 intrinsic elements include running mechan- forces on the tibia.5 Abnormal kinemat- Although distance running provides many ics, anatomical variations, and individual ics during running can also contribute to positive health effects, injuries can and health factors including poor bone health altered loading patterns on the tibia.5 Pohl do result from this training mode. Over- (osteoporosis and low bone density). et al5 identified increased peak hip adduc- use injuries frequently occur in the lower Evidence suggests that improper train- tion, peak rearfoot eversion, and peak abso- extremities due to repetitive tissue stress.1 ing regimens are a key extrinsic factor in lute free moment as significant predictors of Edwards et al2 estimate that 26% of recre- the occurrence of stress fractures. According tibial stress fractures. Hindfoot and forefoot ational and 65% of competitive runners will to Reeder et al,3 it is important to focus on varus and compensatory hyperpronation sustain some form of overuse injury in any the runner’s training regimen and history in were also linked to tibial stress injuries.12 Orthopaedic Practice Vol. 27;1:15 37 Bennell et al13 describe reduced muscle ing running volume is a factor in prevent- process consisted of one reviewer further size and strength, particularly in the calf ing an overuse or reinjury as it allows the assessing the title and qualitatively review- muscles, as another predisposing factor to body to gradually adjust to external impact ing the abstract of each paper. For a paper to stress fractures. Additionally, the interplay forces.16 The 10% rule alone however does be retained for further scrutiny, the title or between running mechanics and factors not adequately address the variance among the abstract had to be associated with tibial related to bone healing suggest that changes runners, or the numerous factors that can fractures, use humans as subjects, or allude in stride length and running speed may contribute to a stress fracture. In fact, Ben- to running related protocols. Exclusion cri- also be important to consider as an athlete nell et al13 reported there are no published teria for this stage of the selection included returns to running. studies comparing different return to run- femur, fibula, tarsal and foot bone fractures, Anatomical factors play a role in pre- ning programs that include evidence for muscular related running injuries, and lower disposition to stress fractures. Clinically progressive increases in loading. Despite the extremity injuries related to athletic activi- relevant leg length discrepancy is found to lack of evidence, the 10% rule has become ties other than running. increase the likelihood of stress fractures in a well-known standard rehabilitation proto- The third and final stage of the study an athletic population.13 A pes cavus foot is col for returning runners to their prior level selection involved two reviewers reading the linked to stress fracture incidence; because of training. Therefore, the purpose of this title, abstract, and full text of each article, this foot type is more rigid, it does not review was to examine the evidence behind again searching for relevance to our review’s absorb shock and passes impact forces to the 10% rule for return to running follow- purpose. Papers included during this final the tibia therefore increasing risk for a tibial ing a tibial stress fracture, and to develop an stage were confirmed via reading of the full stress injury.13 Abnormal lower extremity evidence-based and safe return to running text to include clear references to risk factors range of motion such as increased hip exter- program post tibial stress fracture. associated with stress fracture in addition nal rotation and decreased ankle dorsiflexion to return to running protocols, or currently are also associated with stress fractures.13 METHODS accepted treatment of tibial stress fractures. There are also physiological factors that Search Strategy Papers were excluded if they were opinion affect injury risk. A history of injuries is a The databases of Medline, SportDis- pieces/case studies, included only a limited significant health factor associated with cus, EMBASE, PEDRO, CINAHL, the population (females only, military only, pro- lower extremity injury, as is poor physi- Cochrane Library, and the National Guide- fessional athletes only), or were determined cal fitness