IntroductionGiven the absence of a satisfying plate system to deal with multifragmentary or subcapital distal ulnar fractures, the Distal Ulna Locking Plate (DUL, I.T.S. GmbH, Graz, Austria) could become a useful treatment option. This study aimed to evaluate the results of this anatomically pre-contoured plate regarding patients with unstable or displaced distal ulnar fractures.MethodsIn a prospective clinical trial, 20 patients (18 female, two male; mean age 70 years (24–91 years)) with unstable or displaced distal ulna fractures between December 2010 and August 2015 were analyzed. All patients were treated with open reduction and internal fixation using the DUL. They were evaluated at three follow-up appointments at 3, 6 and 12 months postoperatively regarding their bone healing, ulnar variance (UV), range of motion (ROM) and grip strength. Patient related outcomes were measured using the Disability of the Arm, Shoulder and Hand (DASH), the Patient Rated Wrist Evaluation (PRWE) questionnaires, and the Visual Analogue Scale (VAS). The results after one year were compared to the outcome of the healthy contralateral side.ResultsAll fractures treated with open reduction and internal fixation using the Distal Ulna Locking Plate healed within 6 months and showed stable ulnar variances after surgery. ROM (rotational plane 81.1 ± 9.0°, sagittal plane 55.1 ± 14.6°, frontal plane 33.0 ± 9.4°) and grip strength (18.7 ± 7.1 N) at the follow-up after 12 month had similar values compared with the uninjured side. The mean DASH score (36.4 ± 29.0), the PRWE-score (14.5 ± 27.0), and the VAS (at rest 0.5 ± 1.1, during activity 1.2 ± 2.4) after one year had no significant difference to the uninjured side. The surgeon’s overall satisfaction rate regarding plate handling reached 81.8%.ConclusionStabilization of unstable distal ulna fractures using the DUL restores nearly normal anatomy and function. Its pre-countered design, volar placement, and enhanced stability present a satisfying plate system.Trial registrationThe trial was retrospectively Registered atwww.clinicaltrials.govon 16 December 2021 (Trial Registration Number: NCT05329012).