Talus Visualization in Ankle Fractures: How Much Are We Really Seeing?

Background: Despite appropriate care, a subset of patients with ankle fractures has persistent pain. This condition may be associated with intra-articular pathology, which is present up to 65% of the time. Purpose: To quantify how much of the talus is visible through an open approach to a standard supination external rotation bimalleolar ankle fracture as a percentage of the entire weightbearing surface of the talus. Study Design: Descriptive laboratory study. Methods: Standard ankle approaches to lateral and medial malleolar fractures were performed in 4 cadaveric ankles from 2 cadavers. Osteotomies were made to simulate a supination external rotation bimalleolar ankle fracture based on the Lauge-Hansen classification. The visible segments of talar cartilage were removed. The tali were then exhumed, and the entire weightbearing superior portion of the talus was assessed and compared with the amount of cartilage removed by an open approach. The mean of the data points as well as the 95% confidence interval were calculated. Results: Four ankle specimens from 2 cadavers were used for these measurements. The mean surface area of the talus was 14.0 cm2 (95% CI, 13.3-14.7 cm2), while the mean area visible via an open approach was 2.1 cm2 (95% CI, 0.5-3.6 cm2). The mean proportion of the talus visualized via an open approach was 14.8% (95% CI, 3.6-26.1%). Conclusion: These findings indicate that the true area of weightbearing talar surface visible during an open exposure may be less than what many surgeons postulate. Clinical Relevance: Only a small fracture of the talus is visible via an open approach to the talus during fracture fixation. This could warrant arthroscopic evaluation of these injuries to evaluate and treat osteocondral lesions resulting from ankle fractures.

Characteristics of supination-external rotation Salter-Harris II ankle fractures in computed tomography

Background: Recent literature has shown that Salter-Harris (S-H)Ⅱfractures are the most common ankle fractures and carry a higher rate of growth disturbance. Recent literature has shown that Salter-Harris (S-H) Ⅱ fractures are the most common ankle fractures. CT characteristics of S-H Ⅱ ankle fractures are not well depicted. The purpose of this study was to evaluate supination-external rotation (SER) S-HⅡankle fractures by CT and to analyze the features of the associated fibular fracture to further determine the injury mechanism.Methods: The radiographs and CT with S-H Ⅱankle fractures were reviewed. Patients suffered from SER injury were included. The medial tibial cortex (MTC) of the distal tibia broken or intact, the metaphyseal fracture angle (MFA) 5-10mm proximal to the physis was documented in axial CT. The length of the metaphyseal fragment was measured in saggital CT. The correlation of the upper limits between fibular fracture and metaphyseal fragment was analyzed. In presence of the fibular fracture, the fracture pattern was classified based on the location and morphology of the fracture line.Results: Seventy-nine SER S-HⅡankle fractures were identified. Stage 1 was present in 35 and stage 2 in 44. In axial CT, the mean MFA was 11.2 degrees. MTC was fully broken in one case and 20, in stage 1 and stage 2, respectively (P=0.001). In saggital CT, the mean length of metaphyseal fragment was 35.3mm. The length of this fragment was 35.0mm, 35.5mm, in stage 1 and stage 2, respectively (P=0.868). The upper part of the fibular fracture line was located at the same level or higher than that of metaphyseal fragment. In 44 cases with associated fibular fracture, forty were in distal metaphysis with oblique fracture line for which 4 types were demonstrated with plantar flexion. Other 4 were in distal diaphysis with spiral fracture line.Conclusions: For SER S-H Ⅱ ankle fractures, MTC and orientation of the fracture plane can be shown in CT to help to make an appropriate preoperative plan. In addition to SER, majority of the concurrent fibular fracture was in the distal metaphysis with oblique fracture line and plantar flexion.