Abstract
Objectives
Mallet fractures constitute approximately 30% of mallet finger injuries and their treatment remains controversial. This study aimed to assess the functional and radiological outcomes of mallet fractures treated with closed extension-block pinning.

Methods
A retrospective review was conducted on patients who underwent closed extension-block pinning for mallet fractures between December 2013 and May 2023. Twenty-one patients (76% male) included in the study were analyzed. Clinical and radiological assessments were performed to evaluate bone healing, joint function, pain, and daily functional limitations via QDASH, VAS, Crawford criteria.

Results
The mean age was 36 ± 13 years, with a follow-up duration averaging 53,1 ± 40 months. Mallet finger predominantly occurred due to sports injuries and falls (15 patients, 71,5%). Overall, bone union was achieved in 19 (90,5%) cases. The mean flexion of the DIP joint post-surgery was 67,1 ± 10,9 degrees, with three cases (14,2%) exhibiting extension lag and a mean extension limitation of 6,1 ± 10,3 degrees. Overall, patients reported high satisfaction with finger movements after surgery, with significantly lower postoperative pain and functional impairment scores, particularly among males (p<0,05). According to the Crawford evaluation criteria, 6 patients were classified as excellent, 11 patients as good, 2 patients as fair, and 2 patients as poor outcomes. One instance of postoperative complication noted a pin tract infection.

Conclusion
The closed extension-block pinning technique for mallet fractures offers minimally invasive, easy-to-learn application, fast procedure times, and safe outcomes in short to medium term, but complications such as nonunion may increase in delayed cases

Key words: mallet fracture; extension block pinning; extension loss; mid-term functional outcome; complication