[Simple screw fixation for calcaneal fractures: 60 cases with preoperative computed tomography analysis].

PURPOSE OF THE STUDY: In accordance with the conclusions established at the SOFCOT symposium in 1988, we propose surgical treatment of displaced fractures of the calcaneus with screw fixation after reduction. We developed an original classification system of 3D computed tomography images which allows a precise description of the fractures and guides joint and calcaneal body reconstructions. The purpose of this work was to provide a precise analysis of operated fractures in order to identify prognostic factors and validate use of exclusive screw fixation for calcaneal fractures.

MATERIALS AND METHODS: This series included 60 operated articular fractures of the calcaneus. The Uthéza classification was: 12 vertical, 7 horizontal with 1 fracture line, 3 horizontal with 2 fracture lines, 23 mixed with 1 fracture line and 15 mixed with 2 fracture lines. 3D computed tomography evidenced the fundamental fracture lines and their anterior extension. Fixation was achieved with one screw inserted in a transverse position under the posterior facet and one oblique screw from the greater tuberosity to the sustentaculum tali. The medial and lateral Böhler angles were measured on plain x-rays. The analysis included search for a double line on the posterior talocalcaneal facet, secondary body displacement, the position of the oblique screw and the degree of posttraumatic subtalar wear. The clinical criteria established in the 1988 SOFCOT guidelines were recorded. Analysis of variance, Pearson and Spearman coefficients, and RIDITS analysis (the most powerful method available for evidencing a relationship between two qualitative variables one of which is ordinal) were used to search for prognostic elements and correlations.

RESULTS: No severe complications were encountered with the wide lateral access. A negative medial Böhler angle was significantly correlated with an additional posterior facet line. A mean 80 p. 100 reduction in the lowering of the medial part of the posterior facet and an 87 p. 100 reduction in lateral pivoting were achieved irrespective of the type of fracture. Minimal secondary body displacements were significantly related to anchorage of the oblique screw outside the sustentaculum tali. Functional outcome was satisfactory (very good + good + average) in 75 p. 100 of the cases and physical outcome in 50 p. 100 (very good + good) irrespective of the type of fracture. Outcome was significantly correlated with reduction in the Böhler angle, double lines on the posterior facet, secondary displacement and osteoarthritis.

DISCUSSION: The 3D analysis of posterior facet fractures using our classification was useful in guiding reconstruction with correction of the medial lowering and the lateral pivoting. A negative medial Böhler angle was a factor of poor prognosis: more posterior facet lines, joint wear and deterioration of the functional and physical outcome. Good outcome required good reduction of the Böhler angle and good anchorage of the oblique screw in the sustentaculum tali. Good subtalar mobility was associated with pain relief. Uniform anatomic and pathologic classifications and precise analysis criteria are needed for pertinent comparison between series and proper definition for indications for first-line reconstruction-arthrodesis.

CONCLUSION: Measurement of the medial Böhler angle improves the sensitivity of revision criteria for articular fractures of the calcaneus. Screw fixation has proven its reliability.