Stress fractures are common among army recruits and women are affected more frequently than men. Anne Harriss and Nicola Corkiss examine the case of a female army recruit that shows how to rehabilitate individuals and looks at the evidence base for good practice.
A stress fracture (SF) is a musculoskeletal disorder most commonly found in athletes and military recruits (Milogram et al, 1985). It is a concern for military recruits due to: the expense associated in delaying training completion; the time required for rehabilitation; and the individual’s disillusionment (House et al, 2010).
These fractures result from repetitive high-impact activities including running and marching with weights during training; Roberts et al (2014), Hulkko (1988) and Matheson (1987) report that SFs can occur in the pelvis and spine, but usually affect the lower extremities where weight-bearing forces play a central role, (Aweid et al, 2013).
There is an abundance of data substantiating that SFs affect females more than males (Macleod et al, 1999), but the incidence is far higher in UK forces as opposed to the US or Israeli Defense Force, (Wentz et al, 2011). The higher risk is attributable to women’s lower aerobic capacity, reduced muscle mass, lower bone density and anatomical and hormone-related factors (Wentz et al, 2011).
SFs most commonly affect the tibia, metatarsals, fibula, femur and hip (Reece and Roiz de Sa, 2013), but the incidence of injury site most commonly affected can differ between serving forces (Wentz et al, 2011). This case study examines the impact of a tibial SF on Emma, an army recruit, and on her work related fitness. It examines variables used to assess her fitness for work and the role that the military regional occupational health team (ROHT) had in facilitating her employment.
Emma was referred to the ROHT following repeated episodes of lower leg pain while undertaking physical training. The course instructor requested confirmation of her fitness to continue with the eight-week programme. Emma self-medicated for pain precipitated by load-bearing exercises while running. The minimal discomfort at rest was manageable without analgesia. The training programme incorporated a range of activities with load-bearing components.
Emma, a 23-year logistician, completed her basic recruit training a year previously. Her day-to-day role incorporated warehouse work including moving and handling and computer-based activities. In addition, she undertook two guard duties per month, involving standing at the front gate with a weapon.
Emma’s working hours were variable. Camp-based working hours were Monday to Thursday 0800-1700 hrs and Friday 0800-1230 hrs but it could increase to 12 hours per day over the seven-day duration of any deployment. Physical training and load-bearing marching were integral to the requirements of her post.
Emma stated that she was experiencing discomfort similar to a previous injury sustained in basic training 12 months earlier, diagnosed as shin splints. She took a non-steroidal anti-inflammatory drug (NSAID) with good effect. Shin splints differ from SFs, as the pain results from musculoskeletal inflammation as opposed to a fracture (Davis, 2012).
Emma described an insidious onset of pain during load-carrying activities during the first week of the training course. This increased throughout the second week of the course, resulting in her slowing down in a group march, which led to her withdrawal from the activity. Her course instructor requested an assessment of her fitness to complete the training.
Pathology of stress fracture
Brukner and Khan (2006) describe an SF as an incomplete fracture resulting from stress on a localised area of bone. It is not attributable to a specific traumatic event, but by an unaccustomed, repetitive loading of the bone (Solomon et al, 2005).
This is typical of any physical military training that has a predisposition to be highly demanding physically, exposing the body to severe stresses in a short period of time (Duran-Stanton and Kirk, 2011). An increase in activity results in micro-fractures with insufficient time for the bone to repair. If not rested, an SF will be the result (Patel et al, 2011). Emma stated that she had experienced no traumatic injury and pain onset had gradually increased with the intensity of her course.
Bone remodeling occurs throughout life and is caused by multiple factors including: metabolic state; nutritional status; menstrual pattern; age; gender; fitness; and ethnicity (Pepper et al, 2006). Emma stated that her nutritional intake was sporadic and she often ate “on-the-go” with little thought for nutritional value.
There is some evidence to support that calcium intake is important in the prevention of an SF in cross-country runners, (Kelsey et al, 2007), but this was not substantiated in a similar study that was carried out in female military recruits (Lappe et al, 2005), with some relevance to Emma due to her cross-country training.
It became apparent that Emma consumed insufficient calories to sustain her on a physically demanding course. Armstrong et al (2004) identified that military personnel have strict eating regimes and limited availability of snacks; therefore they were unable to consume adequate calories. Glycogen depletion and impaired muscle recovery can occur between training sessions (Armstrong et al, 2004).
Women have less bone density than men, increasing their likelihood of sustaining an SF (Davis, 2012). Their bone density is regulated by their menstrual cycle; Emma experienced irregular cycles, often taking her contraceptive pill continuously for menstrual regulation.
Otter et al (1999) cited by Romani (2002) proposed that perfusion and re-perfusion of the bone after repetitive loads resulted in a temporary oxygen deficiency to the bone that was being stressed. This ischemia resulted in bone remodelling and a weakness that would result in an SF.
Romani et al (2002) described how blood normally flows through vessels within the bone and, as forces are applied, bone deforms and blood flow is temporarily restricted, causing a decrease in oxygen perfusion and an increase in osteoclast re-absorption resulting in a decrease in bone density.
A temporary lack of oxygen is not the only cause of ischemia. Repeated pressure to the capillaries is also thought to cause vessel microdamage, allowing fluid to leak into the surrounding tissue. The neutrophil and macrophage proliferation partially restricts the blood flow to the injured area, resulting in a decrease in the oxygen perfusion surrounding the damaged tissue (Romani et al, 2002).
The patho-physiology of an SF explains why Emma was now unable to perform weight-bearing activities even with the aid of analgesia. The pain associated with SFs results from pressure being applied to the bone through weight bearing and it subsides when resting. The area can be swollen and tender to touch (Romani et al, 2014). NSAIDs were prescribed for analgesia.
There is a dearth of research regarding NSAID use in the treatment of SF, with many believing that they slow down bone healing by inhibiting maturation of the callus. It is thought that they do this by affecting the prostaglandin synthesis that has been shown to be essential for healing of an SF (Kidd et al, 2012; Penman, 2002). Others, including Wheeler and Batt (2005), dispute this due to the limited research that has been carried out in humans. Emma was only taking medication when exercising, there were no immediate concerns regarding her use of NSAIDs and the effect they could pose on her recovery. Her functionality was restricted due to pain and her limited ability to carry out her job role associated with the SF.
The principal purpose of a fitness-to-work assessment is to determine the individual’s fitness to undertake their role effectively without risking the health and safety of themselves or others (Palmer et al 2013). Emma’s fitness was assessed using the Murugiah et al (2002) fitness-for-work model, incorporating consideration of personal aspects, work characteristics, the working environment and legal aspects.
The management referral requested confirmation of her fitness to complete the training course and her fitness to return to work. At this time, there was no definitive confirmation that her injury was an SF as the x-ray detected no abnormalities, and so an MRI was booked for the following day.
This assessment indicated that she would be unable to complete her training course. The average recovery period from an SF is estimated to be six weeks. After this time, she would commence a graduated return-to-fitness programme.
(Roberts et al, 2014). Her past medical history suggested that Emma had experienced a similar condition during her basic training but the outcome had not been as limiting as her current injury.
Her functional limitations resulted predominantly from the pain that she was experiencing, impacting on her ability to weight bear, run or stand for prolonged periods of time. This necessitated her being removed from the physical training course (PTC) and returned to her unit.
The initial assessment indicated Emma’s activity level should be reduced to ensure pain-free functionality, otherwise a prolonged recovery period and protracted return to her full potential was likely (Patel et al, 2011). In effect, this had already taken place from her diagnosis of shin splints 12 months earlier.
Emma withdrew from the course. Physically, she could walk with crutches, and so a return to some form of work with adjustments in place was agreed. Knowledge of the job role is imperative when undertaking an assessment (Everton et al, 2014).
The assessment included noting down lifestyle, leisure activities and nutrition as these can impact on successful rehabilitation and could be contributory factors in her injury (Palmer et al, 2013). Emma’s nutritional intake was inadequate for her physical activity, and she had an irregular menstrual cycle, (Davis, 2012), which could predispose her to SFs. These factors were discussed in detail, highlighting aspects that she could change to improve her recovery and reduce the likelihood of reoccurrence.
Characteristics of work
Murugiah et al (2002) highlight the importance of a thorough understanding of job specifications and what would be desirable and essential to find in them. An MRI for Emma confirmed a tibial SF, a physiotherapy referral had been made and pain control achieved. Collaborative working between Emma’s chain-of-command and multi-professional ROHT service was integral to developing a recovery programme. Engagement with management facilitated a holistic understanding of Emma’s role, providing a realistic understanding of adjustments that can be facilitated and incorporated within a six-week recovery programme. A medical discharge could result for those unable to participate in fitness assessments even if able to perform their employment role (Bacon et al, 2012).
It is unusual for military ROHT to have a referral for a soldier unless they are medically removed from the work environment, so this case is unique.
Emma began experiencing symptoms on day three of her course but, due to similar past experience, she believed she could self-medicate to manage her own recovery. A well-informed line manager resulted in a rapid referral: within 10 days of her injury, she had been seen by the ROHT service, and fracture clinic and had received physiotherapy. There was excellent communication between the clinical team and her line manager, ensuring effective working with the same formulated plan of returning her to a fully deployable grade and thus maximizing her working output.
As already highlighted, this soldier had experienced a similar injury, and it could be argued that it reoccurred due to a lack of her understanding of the contributory factors that she exposed herself to. SF is a common injury for both athletes and military recruits, especially females (Wentz et al, 2011).
Within the military environment, great emphasis is placed on maintaining soldiers on a deployable grade, but what is evident from this case is a soldier regaining their deployable grade should not be the only outcome sought. Should the medical team impart some form of education on the reasonings behind a soldier’s injury, they would be better prepared to avoid a reoccurrence in the future, as with Emma and her SF. The earlier the engagement, the better the outcome (Palmer et al, 2013). In conclusion, Emma sustained an injury common among her peers. With early intervention, education, engagement with treatment and collaborative working, a positive outcome for a return to work was reached.
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