Clinical Outcomes of a Novel A5/A4 Pulley Security Suture in the Treatment of Zone 1 FDP Avulsion Fracture

<b>Background:</b> In patients with a zone 1 flexor digitorum profundus (FDP) avulsion fracture, we suture the FDP tendon to the A5 or A4 pulley using an absorbable suture as an adjunct to standard surgical fixation. This minimises the proximal retraction force of the tendon during the early postoperative period. The aim of this study is to report the clinical outcomes of this approach. <b>Methods:</b> This is a retrospective study of all patients who underwent this technique over a 2-year period between January 2020 and December 2022. Patients aged 18-65 with isolated zone 1 FDP avulsion fracture and who complied with physical therapy and follow-up protocols were included. Demographic information, injury details, surgical methods and postoperative outcomes, including range of motion (ROM), Strickland score, grip strength and Quick disabilities of hand, shoulder and arm (Quick-DASH) score were measured. <b>Results:</b> Eight patients (three females, five males; average age 45.75) were included. Injuries occurred in the ring finger (3) and little finger (5), with sports-related injuries being the most common cause (4). Surgical methods varied, including K-wire, pull-out techniques and combinations of these techniques. At 1-year follow-up, the average active ROM was 87.5° ± 10.9° in the proximal interphalangeal (PIP) joint and 46.9° ± 11.5° in the distal interphalangeal (DIP) joint. Strickland score was excellent in two patients, good in four and fair in two. Grip strength averaged 78.12% of the contralateral side. Quick-DASH scores averaged 14.6 ± 6.8. No tendon ruptures or implant failures were observed. <b>Conclusions:</b> The absence of rupture and satisfactory functional outcomes suggest that this technique is a viable option for treating zone 1 FDP avulsion fracture. Further studies with larger sample sizes and longer follow-up periods are warranted. <b>Level of Evidence:</b> Level IV (Therapeutic).