Background/Objective <p>Doyle type 4c mallet finger, characterized by fracture fragments involving over 50% of the distal interphalangeal (DIP) joint surface, is traditionally managed surgically. However, the optimal treatment for patients without volar subluxation remains debated. This study aimed to compare clinical, radiological, and functional outcomes of surgical versus conservative management in Doyle type 4c mallet finger without volar subluxation.</p> Methods <p>A retrospective review included 39 patients (18 surgical, 21 conservative) with Doyle type 4c mallet finger. Surgical patients underwent the extension block technique, while conservative patients were treated with a Stack splint for 6–8 weeks. Outcomes assessed at final follow-up included DIP joint flexion, extension lag, dorsal prominence, Visual Analog Scale (VAS) scores, and Crawford classification. Radiographic evaluation included fracture displacement, postoperative articular step-off, and union.</p> Results <p>Preoperative fracture displacement was greater in the surgical group (<i>p</i> &lt; 0.001). At final follow-up postoperative articular step-off was higher in the conservative group (<i>p</i> &lt; 0.001). No significant differences were observed in DIP flexion, extension lag, or VAS scores. Dorsal prominence was more frequent in the conservative group (<i>p</i> = 0.028), whereas Crawford scores and complication rates were comparable (<i>p</i> = 0.435 and <i>p</i> = 0.288, respectively).</p> Conclusion <p>Conservative management with a Stack splint provides satisfactory functional outcomes in Doyle type 4c mallet finger, even for large fracture fragments. Complication rates were low, suggesting that large-fragment mallet finger cases can be effectively managed conservatively.</p> Level of evidence <p>IV</p>