Amputation-related back pain: Prevalence, associated risk factors and correlation with functional disability

ABSTRACT

To determine the prevalence and associated risk factors for post-amputation back pain in lower limb amputees, and to evaluate post amputation back pain-related functional disability. Nested case control study included fifty three lower limb amputees who were more than one year post amputation and ambulatory with prosthesis. All studied lower limb amputees were underwent full history taking, measurement of intensity, frequency and duration of post amputation back pain and measurement of post amputation back pain - related functional disability by using of the revised Oswestry low back pain disability questionnaire [RODQ]. The prevalence of the reported back pain by the studied sample of the lower limb amputees was 64%. The mean of back pain intensity was 5.6 +/- 2.4. The majority of these with post amputation back pain [62%] described their back pain as intermittent and 38% described their back pain as constant. More than twenty three percent of lower limb amputees reported their average back pain intensity as mild [1-4], 50% reported their average back pain as moderate [5 or 6], and 26.5% reported their average back pain as severe [7-10]. As age increased, the odds of development of back pain increased. The prevalence of back pain in men was more than in women [OR =1.8, 95% CI = 1.2-2.3]. The odds of development of back pain in lower limb amputees who resided in an urban areas was higher than that in who resided in rural area [OR =3.8, 95% CI = 2.9 - 4.6]. The odds of development of back pain was higher in lower limb amputees with low education level than in those with high education level [OR = 2.6; 95% CI =1.6-2.9]. Diabetes mellitus as a reason of lower limb amputation associated with the highest risk of development of back pain in lower limb amputees [OR=3.4; 95% CI=2.9-5.1]. The transfemoral amputation associated with a higher risk of development of back pain than the transtibial amputation [OR=3.6; 95% CI=2.1-4.2]. As the time since amputation increased the risk of development of back pain increased [OR of > 2years = 3.2; 95% CI 2.8 -3.6]. The risk of development of back pain in lower limb amputees increased with increasing of duration of daily use of their prosthesis [OR of >/= 5 hours use =4.4; 95% CI= 3.1- 5.3]. As the number of co morbidities increased, the risk of development of back pain increased [OR of one sephantom limb pain was associated with a high risk of development of back pain [OR =2.4; 95% CI= 1.9-3], Also, presence of residual limb pain increased the risk of development of back pain in lower limb amputees [OR=2.6; 95% CI=1.7-3.2]. However, pain in non amputated limb was not associated with odds of development of back pain [OR=0.8; 95% CI=0.3-1.3]. A significant difference was found between the functional disability in lower limb amputees with post amputation back pain and those without back pain [t = 3.2, p< 0.05]. A significant positive correlation was found between the degree of intensity of back pain in the lower limb amputees and the level of back pain - related functional disability [r = + 0.7, p< 0.5]. The prevalence of back pain among the lower limb amputees is high. Identifying risk factors in this study helps to determine the characteristics of lower limb amputees toward whom to direct measures to prevent post amputation back pain. Measurement of back pain intensity is important to assess the back pain-related functional disability