Background Assessment of tibiofibular reduction presents an intra- and postoperative challenge. Numerous two-dimensional measurement methods have been described, most of them highly dependent on leg orientation and rater. Aim of the present work was to develop a standardized and orientation-independent 3D based method for the assessment of syndesmotic joint position. Methods In a retrospective single center study, 3D models of bilateral ankle joints, either after unilateral syndesmosis stabilization (operative group) or with no injury (native group) were superimposed (best fit matching) and aligned uniformly. Based on center of gravity calculations three orientation- and rater-independent parameters were determined: tibiofibular clears space (CS), vertical offset between both fibulae, and translation angle of the fibulae about tibia axis. Results Bilateral CT datasets of 57 native and 47 postoperative patients were analyzed. In the native group mean CS was 2.7 (SD, 0.8; range, 0.7–4.9) mm, mean CS side difference was 0.62 (SD, 0.45) mm and mean translation angle was 1.6 (SD, 1.4) degrees regarding absolute values. The operative group was found to show a significantly higher CS side difference of 0.88 (SD, 0.75) mm compared to native group (P = .046). Compared to the healthy contralateral side, operated fibulae showed mean proximal displacement of 0.56 (SD, 1.67) mm (P = .025), dorsal displacement of 1.5 (SD 4.1) degrees (P = .017). Conclusion By using 3D best fit matching, orientation- and rater-dependent errors can be minimized. Large interindividual and small intraindividual differences of uninjured couples support previous recommendations for bilateral imaging. Trial registration: AZ 131/18-ek; AZ 361/19-ek Level of evidence Level III.

No abstract

Purpose To analyze the indications, radiological short-term outcomes, and complications of ankle fractures in geriatric patients treated with a triangular external fixator (AEF) until fracture healing. Furthermore, the effect of an additional osteosynthesis to AEF on the radiological outcome was investigated. Methods Retrospective analysis of ankle fractures treated in a Level I Trauma Center between 2005 and 2015 with an AEF in patients aged ≥ 65 years until fracture has healed. The combination of AEF and at least one additional osteosynthesis of a malleolus was defined as hybrid external fixator (HEF). At the time of AEF removal, a preserved ankle joint congruity was defined as good radiological outcome. Incongruity more than 2 mm was defined as poor radiologic results. Results 16 patients (13 women, 3 men) with a mean age of 74 years (SD 6.2) were treated with AEF until fracture healing, 9 with a single AEF and 7 with a HEF. Stabilization with HEF (n = 7 [100%]) showed higher rates of good radiological outcome than AEF alone (n = 4 [44%] of 9; p = 0.034). The duration of therapy did not differ between HEF and AEF (70 day vs 77 days). 4 patients (22%) required surgical revision. Conclusion It could be shown that osteosynthesis in addition to AEF leads to a better radiological short-term results than using AEF alone. Therefore, in the situation where an AEF is considered as the definitive treatment option for an ankle fracture in geriatric patients with expected or existing soft tissue problems, it should be done or completed as a HEF. Level of evidence Therapeutic level IV.

Not available.

Introduction Incongruent stabilization of the distal tibiofibular joint (syndesmosis) results in poorer long-term outcome in malleolar fractures. The aim was to analyze whether the orientation of the syndesmotic stabilization would affect the immediate reduction imaged in computed tomography (CT). Materials and methods The syndesmotic congruity in 114 ankle fractures with stabilization of the syndesmosis were retrospectively analyzed in the post-operative bilateral CT scans. The incisura device angle (IDA) was defined and correlated with the side-to-side difference of Leporjärvi clear-space (ΔLCS), anterior tibiofibular distance (ΔantTFD) and Nault talar dome angle (ΔNTDA) regardless of the stabilization technique and separately for suture button system and syndesmotic screw. Asymmetric reduction was defined as ΔLCS > 2 mm and |ΔantTFD|> 2 mm. Results Regardless of the stabilization technique, no correlation between the IDA and the ΔLCS (r = 0.069), the ΔantTFD (r = 0.019) nor the ΔNTDA (r = 0.177) could be observed. There were no differences between suture button system and syndesmotic screw. Asymmetrical reduction was detected in 46% of the cases, while sagittal asymmetry was most common. No association was found between the orientation of stabilization device and occurrence of asymmetrical reduction (p > 0.05). The results of suture button system and syndesmotic screw were comparable in this respect (p > 0.05). Conclusion Poor correlation between the orientation of the stabilization device and the immediate post-operative congruity of the syndesmosis could be shown. In contrast to current literature, this study did not show difference of suture button system over syndesmotic screw in this regard. Careful adjustment of the fibula in anteroposterior orientation should be given special attention.