Relationship between pain, nerve injury and clinical outcomes after flexor tendon injuries in zones 1-2: a retrospective cohort study

Introduction The influence of pain and a concomitant digital nerve injury on the course of rehabilitation after flexor tendon injury remains ambiguous. The objectives of the study were to: i) analyse the evolution of pain spanning one year after a primary flexor tendon repair in zones 1-3; ii) examine the differences in pain levels in patients with and without digital nerve injury; and iii) evaluate the relationship between pain, digital nerve injury and pain medication, total active motion (TAM), DASH scores and patient satisfaction.Methods Data from 189 patients were retrieved from a flexor tendon registry between 2014 and 2020. Differences in pain, TAM, DASH and patient satisfaction were analysed. Multiple linear and binary logistic regression analyses were performed to determine the relationship between clinical outcomes.Results Pain significantly decreased in the course of rehabilitation (p < 0.001 to 0.006). No relationship could be identified between nerve injury and pain (p = 0.21-0.97). In week 6, the presence of pain and a nerve injury were significantly associated with lower TAM scores (p = 0.001). In week 13, pain during motion (p < 0.001) and the presence of a nerve injury (p = 0.036) were significantly associated with worse DASH scores. Patient satisfaction was significantly inversely correlated to pain during motion in weeks 13 and 26 (p < 0.001).Conclusion We found a significant relationship between pain during motion and pain medication intake, TAM, DASH scores and patient satisfaction. It is therefore advisable to closely monitor this parameter after flexor tendon injuries.