Shoe insoles in the workplace. Can custom-made biomechanic shoe orthoses prevent problems in the back and lower extremities? A randomized, controlled intervention trial of 146 military conscripts. Effect of viscoelastic insoles on pain. Prevention of common overuse injuries by the use of shock absorbing insoles. A prospective study. The effect of insoles on the incidence and severity of low back pain among workers whose job involves long-distance walking. A controlled randomized study of the effect of training with orthoses on the incidence of weight bearing induced back pain among infantry recruits.
Ninety-six women participated in a crossover study to evaluate the effectiveness of viscoelastic polyurethane insoles in reducing back, leg, and foot pain among adults who spend the majority of each work day standing. Twenty-five of the subjects reported that the insoles made their shoes too tight to be comfortable. The remainder, however, found the insoles very comfortable (P less than .002, Wilcoxon, signed-rank test) and reported significant reductions in back pain (P less than .02), foot pain (P less than .03), and leg pain (P less than .007). When these subjects were asked whether they would prefer to wear their shoes alone or with insoles, the preference for insoles was overwhelming (P less than .007, back; P less than .03, leg; and P less than .009, foot pain). It is concluded that viscoelastic insoles can effectively improve comfort and reduce back, leg, and foot pain in individuals who must stand throughout the day. 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.
                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.
                Prospective, randomized, controlled intervention trial.
                One female and 145 male military conscripts (aged 18 to 24 years), representing 25% of all new conscripts in a Danish regiment.
                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.
                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 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.
                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. The purpose of this study was to assess the effect of viscoelastic shoe inserts on pain in nursing students. Students (N = 100) were randomly assigned to control and viscoelastic groups. The viscoelastic group used viscoelastic insoles in their work shoes for five weeks. A pain questionnaire was used to measure location and intensity of post-work pain. The questionnaire was administered as a pre-test and after five weeks. Post-test comparisons between groups indicated significant differences which were not present at pre-test. The viscoelastic group reported a significant peripheral shift in pain location from back to lower extremity; the viscoelastic group also showed significant changes in duration of post-work pain and frequency of pain during the workday. The clinical efficacy of viscoelastic shoe inserts for modifying weight bearing-induced back pain is supported. Further clinical research into the therapeutic and prophylactic value of shock-attenuating shoe inserts for healthy as well as patient populations is advocated. Sedentary individuals, particularly new military recruits, who start a physical training program have a substantial risk of developing an overuse injury of the lower limb. In this study we investigated the effect of neoprene insoles on the incidence of overuse injuries during 9 weeks of basic military training. The experimental group consisted of 237 randomly selected new recruits, while 1151 recruits were the control group. Insoles were given to the experimental group and compliance was monitored. A panel of doctors documented and classified all injuries occurring during the 9 week period. A total of 54 (22.8%) and 237 (31.9%) injuries were reported in the experimental and control groups, respectively. In both groups, the majority of injuries were overuse (experimental group, 90.7%; control group, 86.4%). The mean weekly incidence of total overuse injuries and tibial stress syndrome was significantly lower (P less than 0.05) in the experimental group. The mean incidence of stress fractures was lower in the experimental group but not significantly so (0.05 less than P less than 0.1). This study shows that the incidence of total overuse injuries and tibial stress syndrome during 9 weeks of basic military training can be reduced by wearing insoles. The prevalence and incidence of low back pain in general society is high. Workers whose job involves walking long distances have an even higher tendency to suffer from low back pain. A positive effect of insoles in reducing low back pain was found in professional sports players. This was not examined on people whose job involves walking long distances. In this double blind prospective study we examined the effectiveness of insoles constructed in a computerized method to placebo insoles in 58 employees whose work entailed extensive walking and who suffered from low back pain. The evaluation was performed by the MILLION questionnaire, which is considered as a valid questionnaire for evaluation of low back pain. We calculated the differences of the pain intensity before and after the intervention, in the employees using the insoles manufactured by computer in comparison to the users of the placebo insoles. In each group, the analysis was performed in comparison to the baseline. A total of 81% of the employees preferred the real insoles as effective and comfortable in comparison to 19% of the users of the placebo insoles (P<0.05). The results of this study indicate a substantial improvement in the low back pain after the use of the true insoles. The average pain intensity according to the MILLION questionnaire before the use of the insoles was 5.46. However, after the use of the real insoles and the placebo insoles, the average pain intensity decreased to 3.96 and 5.11, respectively. The difference of the average pain intensity at the start of the study and after the use of the real insoles was significant: -1.49 (P=0.0001), whereas this difference after the use of the placebo insoles was not significant: -0.31 (P=0.1189). The reported severity of pain also decreased significantly: a level 5 pain and above was reported by 77% of the subjects at the start of the study. After the use of the real insoles only 37.9% of the subjects reported a similar degree of pain severity, and 50% of the subjects did so after the use of the placebo insoles (P< 0.05). We did not find a link between low back pain and other variables such as gender, age, number of offspring, work seniority, smoking, previous use of insoles and previous medication. This study demonstrates that the low back pain decreased significantly after the use of real insoles compared to placebo ones. Randomized controlled trial.
                To determine if the use of custom shoe orthoses can lessen the incidence of weight bearing-induced back pain.
                The scientific basis for the use of orthoses to prevent back pain is based principally on studies that show that shoe orthoses can attenuate the shock wave generated at heel strike. The repetitive impulsive loading that occurs because of this shock wave can cause wear of the mechanical structures of the back. Previous randomized studies showed mixed results in preventing back pain, were not blinded, and used orthoses for only short periods of time.
                A total of 404 eligible new infantry recruits without a history of prior back pain were randomly assigned to received either custom soft, semirigid biomechanical, or simple shoe inserts without supportive or shock absorbing qualities. Recruits were reviewed biweekly by an orthopaedist for back signs and symptoms during the course of 14 weeks of basic training
                The overall incidence of back pain was 14%. By intention-to treat and per-protocol analyses, there was no statistically significant difference between the incidence of either subjective or objective back pain among the 3 treatment groups. Significantly more recruits who received soft custom orthoses finished training in their assigned orthoses (67.5%) than those who received semirigid biomechanical orthoses (45.5%) or simple shoe inserts (48.6%), P = 0.001.
                The results of this study do not support the use of orthoses, either custom soft or semirigid biomechanical, as prophylactic treatment for weight bearing-induced back pain. Custom soft orthoses had a higher utilization rate than the semirigid biomechanical or simple shoe inserts. The pretraining physical fitness and sports participation of recruits were not related to the incidence of weight bearing-induced back pain.
There is strong evidence that insoles are not effective for the prevention of back pain. The current evidence on insoles as treatment for low-back pain does not allow any conclusions.
High quality trials are required for stronger conclusions.