Ankle Arthrodesis Combined With Mosaic Bone Autograft Transplantation for End-Stage Ankle Osteoarthritis With Large Cysts of Talar Dome.

End-stage ankle osteoarthritis with large cysts of talar dome can be challenging to treat. Twenty patients diagnosed as end-stage ankle arthritis with large talar cysts between 04/2010 and 02/2016 were randomly divided into experimental group (10 cases) and conventional group (10 cases) by random number method. Patients in the experimental group were treated with ankle arthrodesis combined with a concomitant procedure of mosaic bone autograft transplantation, the conventional group under the ankle arthrodesis. The operation time, intraoperative blood loss, postoperative hospital stay, the time of bone union, and postoperative height of the talus between the 2 groups were compared. The preoperative and postoperative American Orthopaedic Foot and Ankle Society ankle-hindfoot scale score were also recorded and compared. There was no significant difference in the operation time, intraoperative blood loss, and postoperative hospital stay between the 2 groups. The postoperative height of the talus body and the time of bone union were better in the experimental group than that in the conventional group (p < .05). The results of follow-up showed that the American Orthopaedic Foot and Ankle Society scores of the conventional group were lower than those in the experimental group (p < .001). And the incidence of complication (10%) in the experimental group was significantly lower than that in the conventional group (40%). The use of tibiotalar arthrodesis combined with mosaic bone autograft transfer may be potentially an effective option for the treatment of end-stage ankle arthritis with large talar cysts.

[Comparison of stability of sacroiliac screws in the treatment of bilateral sacral fractures in a finite element model].

OBJECTIVE: To compare the stability of sacroiliac screws fixation for the treatment of bilateral vertical sacral fractures to provide reference for clinic application. METHODS: A finite element model of Tile C pelvic ring injury (bilateral type Denis II fracture of sacrum) was produced. The bilateral sacral fractures were fixed with sacroiliac screws in 4 types of models respectively: two bidirectional sacroiliac screws fixation in the S1 segment, two bidirectional sacroiliac screws fixation in the S2 segment, one sacroiliac screw fixation in the S1 segment and one sacroiliac screw fixation in the S2 segment, two bidirectional sacroiliac screws fixation in S1 and S2 segments respectively. By the ABAQUS 6.9.1 software, in the case of standing on both feet, 600 N vertical load was imitated to be imposed to the superior surface of the sacrum and downward translation and backward angle displacement of the middle part of the sacral superior surface and everted angle displacement of the top of iliac bones were extracted for analysis. The stability of sacroiliac screws fixation was compared according to the principle of the better stability the smaller displacement. RESULTS: The stability of 2 bidirectional sacroiliac screws fixation in S1 and S2 segments respectively was markedly superior to that of 2 bidirectional sacroiliac screws fixation in S1 or S2 segment and was also markedly superior to that of one sacroiliac screw fixation in S1 segment and one sacroiliac screw fixation in S2 segment. The vertical and everted stability (the downward translation: 0.531 mm; the everted angle displacement: 0.156° (left side), 0.163° (right side)) of sacroiliac screws fixation in two bidirectional sacroiliac screws fixation in the S2 segment was superior to that of two bidirectional sacroiliac screws fixation in the S1 segment (the downward translation: 0.673 mm; the everted angle displacement: 0.200° (left side), 0.232° (right side)). The rotational stability of two bidirectional sacroiliac screws fixation in the S1 segment (the backward angle displacement: 0.269°) was superior to that of two bidirectional sacroiliac screws fixation in the S2 segment (the backward angle displacement: 0.287°). Moreover, the rotational stability of one sacroiliac screw fixation in the S1 segment and one sacroiliac screw fixation in the S2 segment was inferior to that of two bidirectional sacroiliac screws fixation in the S1 segment or two bidirectional sacroiliac screws fixation in the S2 segment, and the vertical and everted stability of one sacroiliac screw fixation in the S1 segment and one sacroiliac screw fixation in the S2 segment was between that of two bidirectional sacroiliac screws fixation in the S1 segment and two bidirectional sacroiliac screws fixation in the S2 segment. CONCLUSIONS: Two bidirectional sacroiliac screws fixation in S1 and S2 segments respectively is recommended to be utilized for fixing bilateral sacral fractures of Tile C pelvic ring injury as far as possible. It is suggested to choose sacral segments in which sacroiliac screws fixed according to vertical, rotational and everted stability degree of sacral fractures.