ObjectiveTo evaluate the clinical results of the self-manufactured screw director of the calcaneous sustentaculum tali in the surgical treatment of intra-articular calcaneal fractures. MethodsBetween May 2012 and October 2013, 40 patients (47 feet) underwent surgical treatment of intra-articular calcaneal fractures, and the clinical data were analyzed. There were 29 males and 11 females with an average age of 46 years (range, 25-68 years). According to Sanders classification, 17 feet were rated as type Ⅱ, 20 feet as type Ⅲ, and 10 feet as type IV. The average time from injury to admission was 6.02 hours (range, 1-12 hours). All the patients were treated with the screw director of the calcaneous sustentaculum tali to fix the sustentaculum tali. The intraoperative times of fluoroscopy were recorded. The Böhler angle and Gissane angle were measured at pre- and post-operation. The clinical functional outcomes were evaluated according to the Maryland foot score system. ResultsThe intraoperative times of fluoroscopy were 2-4 times (mean, 2.85 times). Radiographic examination showed 45 screws were accurately implanted into the middle of the sustentaculum tali in implanted 47 screws except 1 screw which penetrated into the anteroinferior of the sustentaculum tali and 1 screw which penetrated into the anterior of the sustentaculum tali. The accurate rate of screw implant was 95.7%. All patients were followed up for an average of 12 months (range, 8-18 months). During the follow-up, incision skin necrosis and infection occurred in 2 cases, and sural nerve injury developed in 3 cases. Bone union was achieved at an average of 12.72 weeks (range, 9-18 weeks) postoperatively. The Böhler angle was improved significantly from (6.48±3.67)° pre-operatively to (29.40±4.65)° post-operatively (t=-31.38, P=0.00). The Gissane angle was improved significantly from (99.30±5.85)° pre-operatively to (130.84±5.08)° post-operatively (t=-28.32, P=0.00). The Maryland foot score was 90.66 on average (range, 65-98) at last follow-up; the results were excellent in 41 feet, good in 3 feet, and fair in 3 feet with an excellent and good rate of 93.6%. ConclusionThe self-manufactured screw director of the calcaneous sustentaculum tali can significantly improve the accuracy of the screw implanted into the sustentaculum tali and reduce the harm of intraoperative fluoroscopy to the body.
ObjectiveTo investigate the anatomical characters of the sustentaculum tali (ST), accurate entry point and direction for the placement of ST screw from posterior subtalar joint facet to the constant fragment (CF) in calcaneal fractures.MethodsA total of 100 patients with calcaneal fractures performed ankle CT scans were enrolled between January 2016 and April 2016. According to the inclusion criteria, the clinical data of 33 patients were analyzed, including 18 males and 15 females, with a median age of 41.0 years (range, 18-60 years). There were 16 cases on left side and 17 cases on the right side. Three-dimensional (3D) calcaneal model was reconstructed by Mimics 17.0 software, and the ST anatomical references were measured, including the length of upper and lower edge, the length and height of the midline, the horizontal angle between the midline and foot plantar surface. The parameters of the optimal entry point position (P’ point) and placement angle of the ST screw were determined. The length of ST screw was also measured. The differences between males and females or left and right sides were compared.ResultsThe length of upper edge of the ST was (16.60±2.23) mm, lower edge (20.65±2.90) mm, midline (20.56±2.62) mm, and the height of midline was (9.61±1.36) mm. The horizontal angle between the midline and foot plantar surface was (23.43±3.36)°. The vertical distance from P’ point to the lowest point of the tarsal sinus was (3.09±1.65) mm, while the horizontal distance was (14.29±2.75) mm. The distance from P’ point to the apex of the lateral talus, subchondral bone of subtalar joint, calcaneocuboid joint was (11.41±3.22), (6.59±2.22), (34.58±3.75) mm, respectively. The horizontal angle between the ST screw and foot plantar surface was (–1.17±2.07)°. The anteversion angle of ST screw was (16.18±2.05)° and the length was (41.64 ± 3.09) mm. There were significant differences in the length of upper and lower edge, the length and height of the midline, the distance from P’ point to the apex of the lateral talus, subchondral bone of subtalar joint, and calcaneocuboid joint, and the anteversion angle and length of the ST screw between males and females (P<0.05). There was no significant difference in above all parameters between left and right sides (P>0.05).ConclusionAfter appropriate reduction of the calcaneal fractures, the entry point of ST screw was recommended at about 14 mm posterior and about 3 mm upper related to the foot horizontal line through the lowest tarsal sinus point; and the direction of ST screw placement was about 17° anteversion for males and 15° anteversion for females.