Objective To study the biomechanical differences of the first carpometacarpal joint stability by using different reconstruction methods so as to provide theoretical basis for the clinical choice of reconstruction method. Methods The upper limb specimens were selected from 12 fresh adult cadavers, which had no fracture, bone disease, dislocation of wrist joint, deformity, degeneration, or ligament injury on the anteroposterior and lateral X-ray films. The specimens were randomly divided into 5 groups: normal group, injury group, palmar carpometacarpal ligaments reconstruction group, dorsal carpometacarpal ligaments reconstruction group, and palmar and dorsal carpometacarpal ligaments reconstruction group. Three normal specimens were used as normal group, and then were made of the first carpometacarpal joint dislocation models (injury group); after the first carpometacarpal joint dislocation was established in the other 9 specimens; the volar ligament, dorsal ligament, and volar-dorsal ligaments were reconstructed with Eaton-Little method, Yin Weitian method, and the above two methods in 3 construction groups. The biomechanical test was done to obtain the load-displacement curve and to calculate the elastic modulus. Results During biomechanical test, ligament rupture and loosening of Kirschner wire occurred in 1 case of injury group and palmar carpometacarpal ligaments reconstruction group; no slipping was observed. The elastic modulus values were (11.61±0.20), (5.39±0.12), (6.33±0.10), (7.12±0.08), and (8.30±0.10) MPa in normal group, injury group, palmar carpometacarpal ligaments reconstruction group, dorsal carpometacarpal ligaments reconstruction group, and palmar and dorsal carpometacarpal ligaments reconstruction group respectively, showing significant differences among groups (P<0.05). Conclusion Volar ligament reconstruction, dorsal ligament reconstruction, and volar-dorsal ligament reconstruction all can greatly improve the stability of the first carpometacarpal joint. And the effect of volar-dorsal ligament reconstruction is the best, but the stability can not restore to normal.
ObjectiveTo investigate the effectiveness of limited internal fixation combined with hinged super-articular external fixator to treat type C3 fracture of the distal humerus. MethodsBetween September 2007 and November 2012, 37 cases of type C3 fracture of the distal humerus were treated. There were 22 males and 15 females with an average age of 43.6 years (range, 22-66 years). The causes were accident injury in 24 cases, falling injury in 5 cases, falling from height in 4 cases, heavy crush injury in 2 cases, machine injury in 1 case, and other injury in 1 case. There were 22 cases of open injury and 15 cases of closed injury. The time from injury to operation was 3-46 hours (mean, 18 hours). ResultsNeedle tract reaction and incision infection occurred in 3 cases and 1 case respectively, healing of incision by first intension was obtained in the other cases. Thirty-six patients were followed up 9-48 months (mean, 25.4 months). Heterotopic ossification occurred in 3 cases after operation and no recurrence was found by release after fracture healing. Fractures healed in the other patients after 6-14 months (mean, 9 months) of operation except 1 patient who suffered chronic osteomyelitis. One patient had delayed ulnar neuritis at 12 months after operation, and the nerve function returned to normal after the ulnar nerve transposition. There was no bone ischemic necrosis, elbow joint instability, or loosening of internal fixation. At last follow-up, the average range of motion of injured elbow was 105.0° in flexion,-25.0° in extension, 69.2° in pronation, and 75.6° in supination. According to Mayo elbow joint function score (MEPS) and disability of arm shoulder and hand (DASH) score, the results were excellent in 22 cases, good in 8 cases, fair in 4 cases, and poor in 2 cases with an excellent and good rate of 83.3%; and according to Cassebaum elbow joint function score, the results were excellent in 21 cases, good in 7 cases, fair in 5 cases, and poor in 3 cases with an excellent and good rate of 77.8%. ConclusionA combination of limited internal fixation and hinged super-articular external fixator has satisfactory clinical curative effect for type C3 fractures of the distal humerus, relatively few complications.