title: Can custom-made biomechanic shoe orthoses prevent problems in the back and lower extremities? A randomized, controlled intervention trial of 146 military conscripts.
abstract: BACKGROUND
  Shock-absorbing and biomechanic shoe orthoses are frequently used in the prevention and treatment of back and lower extremity problems. One review concludes that the former is clinically effective in relation to prevention, whereas the latter has been tested in only 1 randomized clinical trial, concluding that stress fractures could be prevented.
  
  
  OBJECTIVE
  To investigate if biomechanic shoe orthoses can prevent problems in the back and lower extremities and if reducing the number of days off-duty because of back or lower extremity problems is possible.
  
  
  METHODS
  Prospective, randomized, controlled intervention trial.
  
  
  METHODS
  One female and 145 male military conscripts (aged 18 to 24 years), representing 25% of all new conscripts in a Danish regiment.
  
  
  METHODS
  Health data were collected by questionnaires at initiation of the study and 3 months later. Custom-made biomechanic shoe orthoses to be worn in military boots were provided to all in the study group during the 3-month intervention period. No intervention was provided for the control group. Differences between the 2 groups were tested with the chi-square test, and statistical significance was accepted at P <.05. Risk ratio (RR), risk difference (ARR), numbers needed to prevent (NNP), and cost per successfully prevented case were calculated.
  
  
  METHODS
  Outcome variables included self-reported back and/or lower extremity problems; specific problems in the back or knees or shin splints, Achilles tendonitis, sprained ankle, or other problems in the lower extremity; number of subjects with at least 1 day off-duty because of back or lower extremity problems and total number of days off-duty within the first 3 months of military service because of back or lower extremity problems.
  
  
  RESULTS
  Results were significantly better in an actual-use analysis in the intervention group for total number of subjects with back or lower extremity problems (RR 0.7, ARR 19%, NNP 5, cost 98 US dollars); number of subjects with shin splints (RR 0.2, ARR 19%, NNP 5, cost 101 US dollars); number of off-duty days because of back or lower extremity problems (RR 0.6, ARR < 1%, NNP 200, cost 3750 US dollars). In an intention-to-treat analysis, a significant difference was found for only number of subjects with shin splints (RR 0.3, ARR 18%, NNP 6 cost 105 US dollars), whereas a worst-case analysis revealed no significant differences between the study groups.
  
  
  CONCLUSIONS
  This study shows that it may be possible to prevent certain musculoskeletal problems in the back or lower extremities among military conscripts by using custom-made biomechanic shoe orthoses. However, because care-seeking for lower extremity problems is rare, using this method of prevention in military conscripts would be too costly. We also noted that the choice of statistical approach determined the outcome.
authors.affiliation: Researcher, The Medical Research Unit, Ringkjøbing County, Ringkjøbing, Denmark. fekl@ringamt.dk
authors.forename: Kristian
authors.initials: K
authors.lastname: Larsen
authors.forename: Flemming
authors.initials: F
authors.lastname: Weidich
authors.forename: Charlotte
authors.initials: C
authors.lastname: Leboeuf-Yde
mesh_terms: D000293:Adolescent; D000328:Adult; D001265:Athletic Injuries / Q000517:prevention & control; D001416:Back Pain / Q000191:economics / Q000517:prevention & control*; D003718:Denmark; D005260:Female; D017048:Health Care Costs; D006801:Humans; D007869:Leg Injuries / Q000191:economics / Q000517:prevention & control*; D008297:Male; D008889:Military Personnel; D009784:Occupational Diseases / Q000191:economics / Q000517:prevention & control*; D009989:Orthotic Devices; D012775:Shoes; D018582:Sick Leave; D016896:Treatment Outcome