ObjectiveTo review the research progress of the biomechanics of proximal row carpal instability (IPRC). MethodsThe related literature concerning IPRC was extensively reviewed. The biomechanical mechanism of the surrounding soft tissue in maintaining the stability of the proximal row carpal (PRC) was analyzed, and the methods to repair or reconstruct the stability and function of the PRC were summarized from two aspects including basic biomechanics and clinical biomechanics. ResultsThe muscles and ligaments of the PRC are critical to its stability. Most scholars have reached a consensus about biomechanical mechanism of the PRC, but there are still controversial conclusions on the biomechanics mechanism of the surrounding soft tissue to stability of distal radioulnar joint when the triangular fibrocartilage complex are damaged and the biomechanics mechanism of the scapholunate ligament. At present, there is no unified standard about the methods to repair or reconstruct the stability and function of the PRC. So, it is difficult for clinical practice. ConclusionSome strides have been made in the basic biomechanical study on muscle and ligament and clinical biomechanical study on the methods to repair or reconstruct the stability and function of PRC, but it will be needed to further study the morphology of carpal articular surface and the adjacent articular surface, the pressure of distal carpals to proximal carpal and so on.
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.