Persistent pain is common 1 year after ankle and wrist fracture surgery: a register-based questionnaire study.

BACKGROUND: Substantial literature documents that persistent postsurgical pain is a possible outcome of many common surgical procedures. As fracture-related surgery implies a risk of developing neuropathic pain and complex regional pain syndrome (CRPS), further studies investigating the prevalence and pain characteristics are required. METHODS: All patients undergoing primary surgery because of ankle or wrist fracture at Hvidovre and Odense University Hospitals, Denmark, between April 15, 2013 and April 15, 2014, were identified from the Danish Fracture Database. A questionnaire regarding pain characteristics was sent to patients 1 yr after primary surgery. RESULTS: Replies were received from 328 patients, of whom 18.9% experienced persistent postsurgical pain defined as pain daily or constantly at a level that interfered much or very much with daily activities, 42.8% reported symptoms suggestive of neuropathic pain, and 4.0% fulfilled the diagnostic patient-reported research criteria for CRPS. CONCLUSIONS: Persistent postsurgical pain 1 yr after wrist and ankle fracture surgery is frequent, and a large proportion of patients experience symptoms suggestive of neuropathic pain and CRPS. Patients should be informed about the substantial risk of developing persistent postsurgical pain. Future studies investigating risk factors for persistent postsurgical pain that include both surgically and conservatively treated fractures are required.

Optokinetic stimulation increases limb pain and forehead hyperalgesia in complex regional pain syndrome.

BACKGROUND: Ambiguous visual stimuli increase limb pain in patients with complex regional pain syndrome (CRPS), possibly due to afferent sensory feedback conflicts. Conflicting sensory stimuli can also generate unpleasant sensations in healthy people such as during motion sickness. We wanted to investigate the mechanisms underlying the link between sensory conflicts and pain in CRPS using optokinetic stimulation (OKS) - a method known to induce motion sickness. METHODS: Twenty-one CRPS patients underwent OKS and rated symptoms of motion sickness. Patients also rated limb pain and pain-related distress before, during and after OKS. In addition, pressure-pain and sharpness sensations were investigated on both sides of the forehead and in the affected and contralateral limb before and after OKS. RESULTS: Limb pain and forehead hyperalgesia to pressure increased in parallel in response to OKS. In a subgroup of nauseated patients who withdrew early from OKS, hyperalgesia to pressure in the ipsilateral forehead persisted longer than in the remaining participants. Sharpness sensations remained constant at all sites. CONCLUSIONS: Sensory conflicts may facilitate pain in CRPS by activating the mechanisms of general facilitation of nociception and, during more severe sensory conflicts, also a facilitatory mechanism that operates mainly ipsilateral to the affected limb.

Electrical impedance assessment of muscle changes following exercise.

Electrical impedance measurements have been assessed as a method of detecting changes in striated muscle following vigorous exercise. Transverse and longitudinal resistivities of the calf and thigh have been measured before and after four subjects ran a half marathon (21 km). No changes were observed in longitudinal resistivity but transverse resistivity rose by an average of 7% following the race. These results are consistent with changes in the muscle fibre membranes or interstitial fluid content.