Original articleCan custom-made biomechanic shoe orthoses prevent problems in the back and lower extremities? A randomized, controlled intervention trial of 146 military conscripts☆
Introduction
The prevalence of back and lower extremity problems in general is high,1 particularly during the first 3 months of military service.2 The most common musculoskeletal problems in the Danish Army are back problems, knee problems, shin splints, Achilles tendonitis, and sprained ankles.2 Shock-absorbing and biomechanic shoe orthoses (BSO) are frequently used in the prevention and treatment of back and lower extremity problems. One review concludes that shock-absorbing insoles in footwear reduces the incidence of stress fractures in athletes and military personnel.3 In several randomized, controlled studies, researchers conclude that preventing overuse injuries in the back and lower extremities by use of shock absorbing insoles is possible.4, 5, 6, 7, 8 We succeeded in finding only 1 randomized clinical trial in which BSO were used for prevention of back and lower extremity problems.9 According to the results from this study, reducing the incidence of stress fractures with semi-rigid and in particular soft BSO is possible.
The theory behind the use of BSO is that control of the subtalar and midtarsal pronation has a positive effect on the closed kinetic, linked movements in the whole lower extremity and back during walking and running.10 Prevention of excessive subtalar and midtarsal joint pronation is thought to prevent excessive medial rotation of the tibia, femur, and pelvis, which in turn prevents further mechanical stress on the knee, hip, and back.10, 11, 12 A connection between subtalar and midtarsal joint problems and lower extremity and back problems has been described.13, 14, 15, 16, 17, 18
The purpose of this trial is to investigate if BSO can prevent problems in the back and lower extremities and if their use can reduce the number of days off-duty during the first 3 months of military service because of back or lower extremity problems.
Section snippets
Study subjects
The estimated sample size was calculated with MEDSTAT (Version 2.12) to 55 subjects per group, with alpha at 5%, beta at 10%, and least relevant difference at 20%. We expected that 10% of subjects would be unwilling to participate and that we would have a drop-out rate of 10%. Therefore, all 154 male and female conscripts (aged 18 to 24 years) from all over Denmark, who were drafted to start in August 1999 at the Jutland Dragoon Regiment, Holstebro, Denmark, were asked to consider joining the
Results
Of the 154 persons drafted, 1 female and 146 male conscripts were available and willing to participate in the trial. One person was excluded because of current use of BSO. After randomization, the two groups consisted of an intervention group of 77 subjects and a control group of 69 subjects (Fig 1). At baseline evaluation, the 3-month period prevalence rates were similar in both groups on all collected data.
At follow-up evaluation, data were collected from 67 (87%) conscripts in the
Discussion
This study clearly illustrates the different results in relation to the choice of analysis. When the actual use of BSO wastested, results were superior to when the actual intervention was tested (ie, intention-to-treat). All significant results were not present in the worst-case analysis.
In addition, estimates of the NNP put the results in perspective. These ranged from 5 in preventing any problems in the back and lower extremities to 200 in preventing off-duty days. However, when the costs of
Conclusion
Although BSO, in accordance with the study by Finestone et al,9 has a statistically significant preventive effect on certain musculoskeletal problems in those who actually use them, the fact that relatively few conscripts seek care for this type of injury prevention is not economically feasible.
References (19)
- et al.
Update and rationale for the intervented functional foot orthosis
Clin Podiatr Med Surg
(1994) - et al.
The shock attenuation characteristics of four different insoles when worn in a military boot during running and marching
Gait Posture
(1999) - et al.
Muskel-og skeletsygdomme i Danmark
Forsvarets registreringssystem til infirmerihenvendelser
(1998)- et al.
Interventions for preventing and treating stress reactions of bone of the lower limbs in young adults
Cochrane Database Syst Rev
(2000) - et al.
Prevention of overuse injuries of the foot by improved shoe shock attenuation. A randomized prospective study
Clin Orthop
(1992) - et al.
Prevention of lower limb pain in soldiers using shock-absorbing orthotic inserts
J Am Podiatr Med Assoc
(1996) - et al.
Soreness in lower extremities and back is reduced by use of shock absorbing heel inserts
Int J Sports Med
(1993) - et al.
Prevention of common overuse injuries by the use of shock absorbing insoles. A prospective study
Am J Sports Med
(1990)
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Submit reprint requests to: Kristian Larsen, PT, The Medical Research Unit in Ringkjøbing County, Amtsradhuset, Torvet 7, DK-6950 Ringkjøbing, Denmark (e-mail: [email protected]).