The Prevalence and Impact of Contralateral Limb Pain in Veterans with Upper Limb Amputation

Background: Upper limb amputees (ULAs) are believed to be at increased risk for contralateral limb pain (CLP), in part, due to overreliance on the sound limb and increased susceptibility to overuse injuries. Upper limb prosthetic devices can be inefficient and uncomfortable and do not fully restore function. Thus, many ULAs reject or abandon prosthesis use, resulting in overreliance on the sound limb for daily activities. CLP impacts an estimated 32.7-35.9% of ULAs, however, prevalence and impact in U.S. Veterans with ULA have not been previously examined.
 
Objectives: 1) Describe the frequency and severity of CLP in Veterans with upper limb amputation; 2) examine the change in pain prevalence and intensity over one year; and 3) quantify the impact of CLP on health-related quality of life (HRQoL) and disability.

Methods: A longitudinal telephone survey of Veterans with ULA was conducted, with data collected at baseline and 1-year follow-up. All Veterans with major upper limb amputation who received care within the VA between 2010-2015 were identified from VA data sources, and mailed recruitment materials. This analysis included those with unilateral ULA who were asked to report whether they had CLP ‘in the past 4 weeks’, and describe the frequency and intensity of pain. The prevalence rates, frequency and intensity of CLP were quantified at baseline and follow-up, and 1-year changes were examined. To examine the impact of CLP intensity on health related quality of life (VR 12 MCS and PCS) and disability (QuickDASH) we developed 3 multivariable linear regression models, controlling for potential confounders.

Results: Eight hundred eight persons completed the baseline survey, and 585 completed both baseline and longitudinal follow-up. Prevalence of contralateral upper limb pain was 72.7% at baseline and 71.6% at follow-up. About 1/3 of participants experienced ‘daily or more frequent pain’ at baseline (31.3%) and at follow-up (32.4%). Average pain intensity at baseline and follow-up was 4.9 (sd 2.3) and 4.8 (sd 2.2) respectively. At one-year follow-up, most participants had persistent pain (59.8%), with 12.8% reporting resolved pain and 11.4% reporting incident pain. Among those with persistent pain, most had no change in pain intensity (56.3%), while 24.4% had improved pain and 19.3% worsened pain. On average, VR-12 MCS scores were 2.7 (CI -5.1, -0.3) and 6.6 (CI -9.9, -3.3) points lower for those reporting moderate and severe CLP, respectively, compared to none to mild pain. On average, VR-12 PCS scores were 4.2 (CI -6.3, -2.1)  and 8.4 (CI -11.1, -5.6) points lower for those with moderate and severe contralateral limb pain, respectively, compared to no to mild pain. Those with moderate and severe pain experienced greater disability; QuickDASH scores were 9.4 (CI 5.9, 12.9) and 20.7 (CI 16.0, 25.4) points higher, respectively, when compared to those with none to mild pain.
 

Discussion: More than two thirds of Veterans with ULA reported CLP. This prevalence rate is much higher than previously reported in the ULA population, and higher than reported in upper limb pain in studies representative of the US population. Over half our population reported persistent pain across the baseline and follow-up with no change in pain intensity. About 1/3 reported daily or more frequent pain. Moderate to severe CLP had a negative effect on mental health, physical health, and increased disability. Further research is needed to understand why prevalence rates in Veterans with CLP are so much higher than those reported in other ULA populations.

Conclusion: CLP is prevalent and persistent in the Veteran ULA population. Moderate to severe CLP negatively impacts health related quality of life and increases perceived disability.