Biomechanical study on different internal fixation methods of joint stability reconstruction of distal tibiofibular syndesmosis injury / 中国骨伤

<p><b>OBJECTIVE</b>To evaluate biomechanical properties in different methods of internal fixation combined with distal tibiofibular syndesmosis injury, in order to provide a theoretical basis for clinical choice.</p><p><b>METHODS</b>Six lower limbs specimens were collected and divided into 5 groups, including normal group, distal tibiofibular syndesmosis injury (injury group), 3 cortexes group, 4 cortexes group and hook-plate fixation group. Neutral position, plantar flexion position (30°), dorsiflexion (20°) supination external rotation position of foot movement were simulated on universal materials tester. Strength, stiffness and stability of ankle joint in 4 kinds of motion conditions were measured.</p><p><b>RESULTS</b>There was significant differences in strength and stiffness of ankle joint between injury group and normal group in 4 different kinds of motion conditions (P<0.05). Strength and stiffness of ankle joint in 3 cortexes group, 4 cortexes group and hook-plate fixation group were improved obviously in 4 different kinds of motion conditions, and biomechanical indexes were recovered normally or better than normal group. Stiffness of the three fixation groups were better than normal group,but there was no significant differences among three groups (P > 0.05), while stiffness of hook-plate fixation group was closed to normal group.</p><p><b>CONCLUSION</b>For distal tibiofibular syndesmosis injury, 1 screw with 3 cortexes, 4 cortexes and hook-plate had a positive impact on strength, stiffness and stability of distal tibiofibular syndesmosis injury stress,and could restore the normal stabllity of ankle joint after reconstruction. While fixing by screw fixation would limit the rototary motion of ankle joint,ankle mortise could not adapt to changes of talus bone, thus induces screw breakage and traumatic arthritis. Hook-plate fixation is more suitable than 3 cortexes or 4 cortexes fixation for bilmechanical properties,and its' stress is more balance and can reduce postoperative complcations.</p>

Case-control study on two different methods in the treatment of Bennett fractures / 中国骨伤

<p><b>OBJECTIVE</b>To compare the clinical outcomes between two different methods in the treatment of Bennett fractures.</p><p><b>METHODS</b>From May 2005 to June 2009, 31 patients with Bennett fractures were treated with gypsum and percutaneous fragment pin fixation. In gypsum fixation group,there were 17 cases including 12 males and 5 females with an average age of (43.9-5.7) years; according to Buechler classification: 3 cases were I region fracture, 11 cases were II region fracture, 3 cases were III region fracture. In percutaneous fragment pin fixation group,there were 14 cases including 8 males and 6 females with an average age of (45.6 +/- 6.1) years; according to Buechler classification: 3 cases were I region fracture, 9 cases were II region fracture and 2 cases were II region fracture. The observing and comparing items of the two groups included: (1) length of stay, time of fracture healing,failure of fixation; (2) postoperative radiographs comparison according to method of Kjaer-Petersen; (3) cannon scores used for outcome measurement.</p><p><b>RESULTS</b>All the patients in the two groups were followed up, the duration ranged from 6 to 15 months,with an average of (9.0 +/- 3.5) months. The length of stay were (7.0 +/- 2.5) d in gypsum fixation group and (9.0 +/- 3.9) d in percutaneous fragment pin fixation group with statistically significant differences (P < 0.05). The postoperative reduction quality according to method of Kjaer-Petersen, in gypsum fixation group:4 patients got an excellent result, 8 good and 5 poor; in percutaneous fragment pin fixation group,the above data were 8, 6 and 0 respectively;there were statistically significant differences (P < 0.05 ) between the two groups. The time of fracture healing were (6.0 +/- 0.5) weeks in gypsum fixation group and (6.0 +/- 1.9) weeks in percutaneous fragment pin fixation group with no statistically significant differences (P > 0.05). Cannon scores were evaluated at postoperative 3 months,in gypsum fixation group: 6 patients got an excellent result, 8 good and 3 fair; in percutaneous fragment pin fixation group,the above data were 8, 5 and 1 respectively; there were no statistically significant differences (P > 0.05) between two groups. Two patients had fracture re-displacement in gypsum fixation group, and no failure cases in percutaneous fragment pin fixation group.</p><p><b>CONCLUSION</b>There are satisfied therapeutic effects in two different methods for the treatment of Bennett fractures. However, gypsum fixation has advantage of easy to operate and atraumatic, but unstability and easy to displacement; percutaneous fragment pin fixation has advantage of fixed solidly and better in functional rehabilitation, but big in surgical trauma and long in length of stay.</p>