[Subtalar fusion after conservative or surgical treatment of calcaneus fracture. A comparison of long-term results].

In a long-term follow-up we evaluated 40 patients out of 55 (73%) with a subtalar fusion. The operations took place from 5/84 to 5/91. In all cases the indication for the fusion was a post-traumatic arthritis after an intra-articular os calcis fracture. The evaluation of the overall results was carried out with three different scoring systems: a. The Hannover Scoring System. b. The Outcome-questionnaire, rating patient's complaints and the functional status based on the severity-symptom scale and functional status described for Carpaltunnel-syndrome by Levine et al. c. The clinical rating system (CRS) described by Kitaoka et al. The statistical evaluation was performed by analysis of variance (ANOVA). Level of significance was based on P = 0.05 and calculation of Pearson's correlation coefficient. The Os calcis fracture was the cause for the subtalar arthritis in all 40 patients (33 males and 7 females). The primary treatment of the calcaneal fracture was conservative (cons.) using a plaster in 23 patients (57.5%), while 17 patients (42.5%) underwent open reduction and plate fixation (op.). The interval between trauma and subtalar fusion averaged 3.5 years (3 months to 20 years). The interval between subtalar fusion and follow-up averaged 5.2 years (4-14 years). The mean age at the time of reexamination was 47 years (26-61 years). In the present study, complete pain relief could be achieved in 21 (52.5%; 58% op., 50% cons.) patients. A relevant restriction in the range of motion in the ankle joint was found in 26 (65%; 76% op., 58% cons.). In 23 patients (62%; 65% op., 59% cons.) the radiological evaluation revealed a grade 1 degree arthritis of the ankle joint, in the talonavicular joint in 17 patients (42.5%; 41% op., 45% cons.), and in the calcaneo-cuboid joint in 14 patients (35%; 47%., 27% cons.). The statistical analysis revealed a better outcome in the operative group compared with the conservative group, although the operated os calcis fractures in the majority were the more severe fracture types. In all evaluation systems a score between 61 and 69 points could be achieved with no significant difference between the operatively and conservatively treated groups and between the newly developed questionaire and the clinical-radiological scoring systems. For the questionaire this fulfills the requirements for a reliable outcome evaluation.