Neuropathic Pain Mechanisms in Patients with Chronic Sports Injuries:A Diagnostic Model Useful in Sports Medicine?

Objective.The pathophysiology of chronic sports injuries such as overuse or tendinopathy remains largely unknown. With this exploratory study, we aim to detect signs of sensitization of the nervous system. Sensitization is an indication of the involvement of neuropathic mechanisms in patients with chronic sports injuries.Design.Sensory descriptors were assessed by means of a neuropathic pain questionnaire (DN4-interview) and by three methods of sensory testing. The test results were integrated in a scoring system.Setting.Patients were recruited from an outpatient clinic of a University Medical Centre and at primary care physical therapy practices.Patients.Fifteen athletes with a unilateral chronic sports injury were included.Outcome Measures.All subjects filled out the seven-items of the DN4-interview to assess sensory descriptors. Next, the presence of brush-evoked allodynia was assessed and pain thresholds with Von Frey monofilaments and a pressure algometer were measured in all patients to determine signs of sensitization.Results.Based on the scoring system, in 4 out of 15 patients (27%) the presence of sensitization could be detected. In two other patients, signs of hypoalgesia were observed.Conclusions.The involvement of sensitization as an explanation for the pain in chronic sports injuries is credible in a considerable proportion of patients. With respect to treatment, the establishment of such neuropathic pain mechanisms is of clinical significance.