Outcomes of Primary Flexor Tendon Repairs in Zones 2 and 3: A Retrospective Cohort Study

PURPOSE: The aims of this retrospective cohort study were to present outcomes of zone 2 and 3 primary flexor tendon repairs and to evaluate how clinical outcomes change over time within and between zones of injury at weeks 6, 13, and 26. METHODS: Data were retrieved from a multicenter flexor tendon cohort registry from 2014 to 2021. The inclusion criteria were: (1) adult patients after primary flexor tendon surgery in zone 2 or 3, (2) flexor digitorum profundus laceration of >50%, (3) 4–6 multistrand flexor digitorum profundus core suture, and (4) early active motion protocol. The primary outcome was the range of motion. Secondary outcomes were strength, patient satisfaction on an 11-point Likert scale, and self-reported physical function measured with the Disability of the Arm, Shoulder, and Hand questionnaire 6, 13, and 26 weeks after surgery. RESULTS: We evaluated 33 patients after 39 tendon repairs in zone 3 and 174 repairs in zone 2 of 163 patients. Range of motion significantly improved over time in both zones (P < .001 to .01). Between-group range of motion differences were nonsignificant except for week 26 (P < .001) for the zone 3 group. Hand strength significantly improved in both zones over time (P < .001 to .01), while between-zone strength differences were statistically nonsignificant (P = .37 to .93). Patient satisfaction was generally good to high (mean 6.8 to 8.0 points) with significant within-group changes in both zones (P < .001). There were no relevant between-zone differences in Disability of the Arm, Shoulder, and Hand scores at any time point. CONCLUSIONS: Patients had significantly improved clinical outcomes in both zones. The zone of injury significantly affected the total active motion scores at the final assessment after 26 weeks for the zone 3 injuries. For the secondary outcomes hand strength, patient satisfaction, and Disability of the Arm, Shoulder, and Hand scores, we discovered no significant between-group differences. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.