Biopsychosocial factors and low back pain in military personnel with lower limb loss: the ADVANCE study.

INTRODUCTION

Biopsychosocial factors influence low back pain (LBP) in the general population but may affect people with lower limb loss (LLL) differently. The first aim was to investigate the relationship between LBP, disability and injury status. We hypothesised that those with LLL (no lumbosacral injury) will have more LBP and functional disability than those with (i) non-lumbosacral and non-amputation trauma and (ii) a non-injured comparison group, but less LBP and functional disability than those with (iii) lumbosacral trauma. The second aim was to report the biopsychosocial factors of LBP for those with LLL (no lumbosacral injury), stratified by functional disability.

METHODS

Military and veteran personnel who did ('exposed', n=578) and did not ('unexposed', n=565) sustain combat trauma completed questionnaires for LBP severity, functional disability and biopsychosocial factors. The exposed group was subdivided into participants with lumbosacral injuries (exposed-lumbosacral (Exp-L)), those with LLL and no lumbosacral injuries (exposed-lower limb amputee (Exp-A)) and those with neither LLL nor lumbosacral injuries (exposed-non-lower limb amputee (Exp-NA)). LBP and functional disability were statistically compared for Exp-A versus unexposed, Exp-A versus Exp-L and Exp-A versus Exp-NA. Biopsychosocial factors were descriptively compared for Exp-A with and without functional disability.

RESULTS

Exp-A had worse LBP and functional disability than unexposed (both p<0.001), less LBP (p=0.02) and functional disability (p=0.001) than Exp-L, but no different from Exp-NA. Exp-A with functional disability experienced more LBP prior to LLL, higher body mass index, greater current opioid use, increased phantom and residuum pain and higher depression scores than those without.

CONCLUSION

LBP and functional disability were significantly worse in participants with LLL (without comorbid lumbosacral combat injury) than controls, although LBP and functional disability scores were low. Biopsychosocial factors, comorbid non-amputation combat trauma (including lumbosacral), history of LBP, phantom and residuum pain are associated with greater functional disability in people with LLL.