Impact of olecranon fracture malunion: Study on the importance of PUDA (Proximal Ulna Dorsal Angulation).

PURPOSE: The Proximal Ulna Dorsal Angulation (PUDA) is part of the proximal ulna's normal anatomy. The importance of restoring ulnar anatomy characteristics precisely after olecranon fracture is not known, however, failure to recreate the PUDA after surgery may result in poorer functional outcomes. The purpose of this study is to evaluate the impact of minimal proximal ulna malunion on elbow ROM and function at least one year after olecranon ORIF. METHOD: A retrospective comparative cohort study took place in three level-1 trauma centers. Forty-nine adult volunteers who underwent ORIF for olecranon fracture were included. Patients were separated into two groups according to PUDA malreduction-defined as more than 5° of difference between the fractured and the contralateral elbow. OUTCOME MEASUREMENTS: Radiographic ROM measurement, demographic data and quality of life questionnaires were recorded (PREE, MEPS, Q-DASH, SF12, VAS). RESULTS: The mean follow up was 3 years and 9 months (1-7 years). There was no difference in terms of outcome, quality of reduction or range of motion between patients treated with plate or tension band. The mean PUDA on the fracture side was different from the normal side (2.20 vs 4.90, p<0.001). Fourteen patients (29%) had PUDA malunion. Those patients had decreased elbow flexion (-7°, p=0.011), extension (-11.2°, p=0.013) and total ROM (-18.6°, p=0.006) as opposed to the control group. Both groups had comparable quality of life questionnaire scores. Alcohol consumption was the only risk factor associated with worse scores. CONCLUSION: Incidence of olecranon malunion-as defined by PUDA measurement - was 29% and it was associated with decreased elbow range of motion. Alcohol consumption was correlated with a worse prognosis in our series of patients. Tension band and plate fixation can maintain a good reduction in terms of PUDA and the choice of fixation method does not influence outcome. LEVEL OF EVIDENCE: III Therapeutic study.