Osteoporosis: A factor on residual limb pain in traumatic trans-tibial amputations

Residual limb pain is defined as a painful sensation or feeling from the remaining part of the leg. Aggressive bone edge, bone spur formation, neuroma, abscess or bursitis are common causes of residual limb pain. On the other hand, regional osteoporosis on femur and tibia is an inevitable consequence in patients with lower limb amputations. The etiology of bone loss is uncertain but it is likely to be a local phenomenon in lower limb amputees. Altered gait pattern, decreased weight load, disuse atrophy and lack of muscular action at the limb seem to be important causal factors in the development of both local and generalized osteoporosis. The aims of this study are: (i) To determine if there is significant bone mineral density (BMD) difference at proximal tibias and femurs between intact and amputated limbs, (ii) to investigate the factors affecting bone loss in these areas and (iii) to investigate the possible relationship between residual limb pain and local bone loss. The 36 men who participated in this study had amputations due to land-mine injuries. Dual energy X-ray absorptiometry was used to determine BMD of the proximal femur and proximal tibia. The non-amputated limb was used as a control for the amputated side. BMD values on the amputated side were significantly lower than non-amputated side. In addition, BMD values on the amputated limbs with residual limb pain were significantly less than in those without residual limb pain. Insufficient mechanical loading leads to bone loss in patients with trans-tibial amputations. Furthermore, bone loss at tibia may be a cause of residual limb pain. However, this needs to be confirmed with more specific studies in the future.