Introduction
The American Medical Association defines shin splints as "pain and discomfort in the leg from repetitive running on hard surfaces, a forcible use of the foot flexors; diagnosis should be limited to musculotendinous inflammation excluding fracture and ischemic disorders."1 Little progress has been made in drawing distinct boundaries between the numerous pathological conditions of the shin, such as medial tibial stress syndrome, stress fracture, and compartment syndrome. Therefore, any type of shin pain is often diagnosed by clinicians as "shin splints." There is evidence that these conditions exist along a bone stress injury continuum, which may ultimately result in a fracture.2 Stress reaction in bone is a significant problem among military recruits and athletes.3 The incidence of shin splints in the military was shown to be ~4% in a training population.4 Because of the cost involved in managing these injuries, as well as lost training time and unit readiness, an effective intervention for shin splints would be beneficial to the military. The purposes of this study were to review current shin splint management practices, to present preliminary data on treatment using the Shin Saver orthosis, and to propose a treatment-based classification system for the management of shin pain.
Conventional Treatments
Currently, little evidence exists in the literature to support the use of the most commonly applied interventions for the treatment of shin splints. Traditional treatments include cryotherapy, stretching and strengthening, the use of nonsteroidal anti-inflammatory drugs (NSAIDs), modification of training regimens, orthotic devices to correct for biomechanical abnormalities, and rest.
Cryotherapy
In a study involving >2,700 midshipmen, Andrish et al.4 found that subjects with shin splints who were assigned to a treatment program using only rest and ice application showed statistically significant results, compared with four other treatment options (p < 0.03). Military facilities commonly use ice massage or crushed ice for the treatment of lower extremity overuse injuries such as shin splints. Unfortunately, limited access to this modality may render it impractical in some training populations.
Stretching and Strengthening
Stretching, although commonly used to treat shin splints, has not been proved effective by current research.4-6 Stretches typically prescribed for shin pain are directed at the triceps surae complex and include the sitting towel stretch and the standing calf stretch.7 A number of experts suggest using ankle-strengthening exercises in the management of shin splints.1,5,7,8 At present, data supporting or refuting the implementation of stretching and strengthening programs for treatment of shin splints remain equivocal.
NSAIDs
NSAIDs have been recommended as part of a comprehensive treatment program for the treatment of shin splints.1 NSAIDs are a commonly prescribed pharmacological treatment for pain and inflammation9 and are regularly used in military clinics for these effects. It can often take as long as 10 to 14 days before significant anti-inflammatory effects are noted.10 The risks associated with taking NSAIDs at this level often outweigh the potential benefits.11-13 There is a 1 to 3% chance that the patient may experience significant side effects associated with higher anti-inflammatory dosages, including gastrointestinal ulcers, bleeding, or perforation.11-15 Clinicians may consider acetaminophen as a practical option for pain control if inflammation is not a concern.
Modification of Training Regimens
Yeung and Yeung16 examined the effects of altering training variables, including frequency and duration, reduction in running distance, and graduated running programs, on the incidence of injury. Their findings suggested that reductions in training frequency, duration, and total running distance had significant effects on injury reduction. These reductions were seen only with the implementation of a graduated running program of >2-week duration.16 In a recent Cochrane Database of Systematic Reviews report, three trials were analyzed with a combined total of 2,177 subjects (514 in intervention groups and 1,663 in control groups). The review concluded that reductions in distance, frequency, and duration might be effective in preventing soft tissue injuries associated with running.17
All active duty soldiers in training are required to pass an Army Physical Fitness Test (APFT), which includes a 2-mile run. For this reason, unit leadership has a particular interest in pushing soldiers to improve their running tolerance. Physical therapists at military installations typically use a graduated walk-to-run protocol intended to return soldiers to a level of function consistent with their operational requirements. Walk-to-run programs theoretically impart an appropriate amount of stress to remodeling bone and soft tissue, ensuring optimal strength and tissue integrity in accordance with the dictates of Wolff's Law.18 To date, no data exist showing whether these programs affect the amount of time required to return these soldiers to full duty.
Relative Rest
Numerous authors have commented on the effectiveness of rest as a treatment for shin splints. Bates8 and others suggested that rest allows time for healing and inflammation reduction.5,19-22 Similarly, Kortebein et al.20 stated that the initial management of medial tibial stress syndrome usually entails some type of relative rest of the involved extremity (specifically from the inciting activity, most commonly running). Beck5 stated that 61% of orthopedic surgeons recommend rest, for 1 to 16 weeks (mean, 6.6 weeks; SD, 3.5 days), as the primary treatment for medial tibial stress syndrome. Multiple studies support rest from high-impact activity as an essential treatment option for overuse-type injuries.4,5,8,19-22 However, no agreement on specific guidelines for the amount and timing of rest required could be drawn from these sources. One study stated that the recommended treatment of stress injuries is usually 2 to 12 weeks of rest of the injured limb.22 Resumption of activity is often not advised until pain has disappeared completely. A gradual return to full activity is purportedly of utmost importance in preventing the recurrence of shin splints.4,21 These findings are consistent with current practice patterns in Army clinics.
Shoe Orthotics
In a recent Cochrane Database of Systematic Reviews report, data pooled from 12 studies indicated that shock-absorbing insoles could decrease stress fracture incidence by >50%.23 Although the quality of evidence was rated as poor to moderate, the positive treatment outcome should not be dismissed.
Shin Orthoses
In a recent randomized controlled trial, Allen et al.24 investigated the effects of a pneumatic leg brace on return to activity and pain among soldiers with tibial stress fractures. The investigators determined that the Aircast leg brace (Aircast Corp., Summit, New Jersey) demonstrated no additional benefit in the treatment of tibial stress fractures in a military training population. This contrasted with the report of Swenson et al.,25 who reported a substantial positive effect using the Aircast leg brace in the treatment of tibial stress fractures in a collegiate athlete population. A relatively new device has been marketed for the management of shin pain. Alimed (Dedham, Massachusetts) advertises that the Shin Saver orthosis "helps reduce the deep muscle ache associated with shin splints." Repeated attempts to contact Alimed regarding research supporting this claim were unsuccessful. The Shin Saver is an elastic neoprene sleeve with a padded aluminum bar designed to be centered over the most symptomatic portion of the medial or lateral leg (Fig. 1). Although no evidence currently exists to support this claim, this study provides preliminary data on the use of this orthotic device for a military training population.
Methods
Subjects
Twenty-five active duty soldiers diagnosed with shin splints were randomly assigned to a shin orthosis group or a traditional treatment group. Exclusionary criteria included soldiers who were diagnosed with a stress fracture with triple-phase bone scans, had <6 weeks remaining in training, or had concurrent lower extremity pathological conditions that would limit their ability to complete a requisite 0.5-mile run.
The institutional review board of Brooke Army Medical Center (San Antonio, Texas) approved this study. All eligible subjects were advised of the potential risks and benefits of participating in the study, and all subjects completed an informed consent form. No external funding was received for this study; however, the Shin Saver shin orthoses were donated by the manufacturer (Alimed).
Procedure
All subjects meeting the aforementioned requirements were randomized by using a random-number generator and were blocked in groups of four to either a shin orthosis (experimental) group or a traditional treatment (control) group. Subjects in the experimental group were fitted with the Shin Saver orthosis according to the manufacturer's instructions. Subjects were instructed to place the bar over the area of pain and wear the brace during all daily activities, except when bathing or sleeping. Subjects were advised to adjust the brace if wear caused pain or skin breakdown. Treatment for the experimental group included use of the orthotic device, a prescription for activity modification, and ice massage after each biweekly assessment. Treatment for subjects in the control group was identical to that for the experimental group except that no orthotic device was used.
Seven days after enrollment in the study, subjects began a walk-to-run program. The program consisted of walking 1 mile on a track, followed by a run of up to 0.5 mile. Before each assessment, each subject was instructed to run at his or her own pace until 10 sequential steps of pain were experienced or 0.5 mile of running was completed. Subjects continued with this protocol until they were able to successfully complete a 0.5-mile run pain free or until they completed their 6th week of study participation. Six weeks was established as the endpoint because of field training requirements that would prevent the subjects from attending further assessment sessions.
Data extracted from each session included pain scores before and after activity and the distance run before the onset of pain, with a global rating of change (GRC) upon completion of the study. Each subject's perception of pain was evaluated before and after the walk-to-run program using a 10-cm, unmarked, visual analog scale (VAS) for pain, as described by Price et al.26 The VAS has been demonstrated to be reliable,26-28 generalizable,27 and internally consistent27,28 in measuring pain sensation and intensity. Clinically meaningful changes in VAS results are defined as ≥1.5 cm.29-31 The GRC quantified subjects' selfperceived improvement. Clinically meaningful changes for the GRC are defined as ≥2 points.32
Statistical Analyses
Independent t tests were used to analyze categorical variables. The independent variable was group, with two levels (experimental and control). Dependent variables were days to completion of the 0.5-mile run, number of treatment sessions to completion, and GRC assessment. The α level was set at 0.05 for all tests. Data analyses were performed using Microsoft Excel for Windows 2000 (Microsoft, Redmond, Washington).
Results
Of the 25 subjects initially enrolled in the study, seven from the experimental group and six from the control group completed all elements of the study. Six (46%) experimental group subjects and six (50%) control group subjects did not complete the study. Three of the experimental group subjects were excluded from the study following enrollment after subsequent diagnosis of a tibial stress fracture. Two dropped out within the first 2 weeks after positive bone scan findings. The third subject was diagnosed later in the study because of delayed administration of the bone scan. The remaining subjects who did not complete the study were dropped because of failure to return for scheduled follow-up visits or because of permanent change of station. The enrollment period extended from May 2002 to October 2002.
Descriptive statistics for all 25 subjects by group are shown in Table I. Baseline values for the two groups were not significantly different with respect to age (p = 0.77), height (p = 0.49), weight (p = 0.30), or initial VAS score (p = 0.19). VAS scores at intake versus after 1 week of relative rest (before and after runs) revealed no significant improvement in symptoms in either group. No significant difference in the days to completion of the 0.5-mile run (p > 0.575; power, 0.65; meaningful effect size, 14 days), in the GRC (p > 0.578; power, 0.39; meaningful effect size, 2 points), or in the number of treatment sessions required (p > 0.889; power, 0.48; meaningful effect size, two sessions) was noted between groups. Values are shown in Table II. Two subjects reported some relief of shin pain with the use of the shin orthosis. Five subjects reported no improvement or worsening of symptoms with the device.
Discussion
Soldiers in a training environment with shin splints are subject to a number of factors that may limit their ability to recover from overuse injuries such as shin splints. An intervention that aids in recovery from overuse injuries would be advantageous for both the patient and the military. The present pilot study is the first to assess the Shin Saver by Alimed as a treatment for shin splints. No conclusions about the device's effectiveness were reached because of the small sample size, high dropout rate, small effect size, and resultant low power. Despite multiple months collecting data, researchers were unable to obtain enough subjects to detect a clinically meaningful difference. Several reasons for poor compliance and a high dropout rate were identified. Some subjects admitted discontinuing use of the device because of discomfort. Complaints included local skin breakdown, induration, and/or excessive sweating with the brace (Fig. 2). The nature of a military training environment makes it inherently difficult to study soldiers, whose priorities are predetermined for them. All subjects were in advanced individual training and were occasionally unable to attend scheduled biweekly assessments by researchers if assigned to a morning detail. Direct communication by telephone with the subjects proved difficult to coordinate, making tracking lost subjects nearly impossible. Another factor contributing to the loss of subjects included an Army requirement to pass an APFT before graduating or being allowed to go on leave. Several subjects allowed their physical profiles to lapse and then opted to run with pain to pass the APFT. These subjects were placed back on profile and returned to the study with pain levels higher than their original baseline VAS scores.
The present study provides preliminary qualitative support both for and against the use of the Shin Saver orthotic device for military trainees. Five subjects reported that symptoms did not change or worsened with Shin Saver orthosis wear. These reports may be attributable to the discomfort of the brace or aggravation of an ongoing inflammatory process. A subgroup of responders tended to be more satisfied with treatment and experienced greater subjective improvement in symptoms with the orthosis. Researchers noted that these subjects typically indicated athletic involvement before entering the military. The factors that contributed to their responsiveness to treatment may include those listed above, as well as physical factors that were not assessed in this study.
A diagnosis of "shin splints" is, by its very nature, nonspecific. The general lack of agreement regarding definition, diagnosis, and management of shin splints in the literature illustrates the multifaceted nature of this pathological condition. Successful management of shin pain continues to challenge health care providers serving military and civilian patients. For other highvolume conditions such as low back pain, there has been a call to classify patients based on their response to treatment.33 Despite the apparent practicality and inherent wisdom of this approach, such a management strategy is not widely practiced for shin pain in military clinics. A treatment-based classification system for shin pain would identify patients who respond to a specific intervention based on physical examination findings and the presence of certain predisposing factors. For instance, patient classification could be based on an individual's probability of responding to a distal, local, proximal, or systemic treatment approach.
When considering various classification schemes for shin pain, it is likely that there would be a group that responded well to distal management. Accommodation for different foot types or excessive pronation during running would characterize this type of approach. Strategies using this approach might include rigid or semi-rigid orthotic devices or shock-absorbing insoles. Another group might consist of responders to local treatment around the site of pain. This could include the use of cryotherapy and possibly the Shin Saver orthosis. Patients in the third group might respond best to proximal symptom management, either through manual treatment of joints up the kinetic chain or core strengthening. Members of the fourth classification group could benefit from systemic management through the administration of NSAIDs to reduce pain and inflammation.
One of the few shin splint treatment studies involving U.S. soldiers was a 1974 study by Andrish et al.4 This randomized controlled trial involved >2,700 first-year U.S. Navy midshipmen who participated in a prophylactic regimen to prevent shin pain, with treatment if they developed shin splints. Subjects assigned to a treatment program using only rest and ice application showed significantly better results, compared with four other treatment options (p < 0.03). The other options also included the use of ice and prohibition of running but added modalities such as aspirin, phenylbutazone, heel cord stretching, or a short walking cast for 1 week.4 A comparison between the study by Andrish et al.4 and the current pilot study is difficult because of different training populations, variance in the ability of soldiers to seek care, and the outcome measures used. It would therefore be inappropriate to infer strong commonalities between these studies.
Shin pain management practices currently include a variety of modalities that are unsupported in the literature. Although anecdotal evidence exists for many of these, a thorough evaluation of their effectiveness is necessary to ensure that practitioners are providing evidence-based, cost-effective care. Therefore, the treatment protocol established in the 1974 study by Andrish et al.4 must serve as the cornerstone for shin splint management in a military population. Ice, along with rest, should serve as the minimal treatment for these soldiers. Unfortunately, this intervention is often unavailable in training environments. Access to ice can be improved for soldiers who require it by installing ice machines in all garrison living and training areas. This should be done to remain consistent with the best available evidence for the management of shin pain until more effective methods are identified. Further investigation and development of a treatment-based classification system may enhance our ability to manage this widespread and costly condition.
Conclusions
No conclusions could be drawn regarding the use of the Shin Saver orthotic device in an active duty training population. Until further research is conducted, the authors recommend use of ice and rest as the primary intervention strategy for the treatment of shin splints. A study outlining a treatment-based classification system would be the next logical step.
© 2006 Association of Military Surgeons of the United States Provided by ProQuest LLC. All Rights Reserved.
Source: Military Medicine
