The outcomes of NiTi shape memory alloy four-corner arthrodesis concentrator for carpal collapse / 中华骨科杂志

Objective To evaluate the results of NiTi shape memory alloy four-corner arthrodesis concentrator (NTMA-FCAC) for carpal collapse. Methods We reviewed retrospectively 13 patients who underwent scaphoid excision with four-corner arthrodesis using NTMA-FCAC for carpal collapse from August 2006 to June 2009. There were eight males and five females, with an average age of 38 years (range, 23-61years). The cause of carpal collapse was SNAC in 7 cases, perilunate dislocations in five and SLAC in one.The injury mechanisms included traffic accidents (5 cases), falling from a height (4 cases), crashes (3 cases)and sprain (1 case). Objective measurements included grip strength and range of the wrist. Radiographs were performed in all patients. A visual analogue scale (VAS) was used to assess wrist pain. The results were evaluated according to the Krimmer wrist scores. Results The mean follow-up time was 26.5 months (range,6-36 months). Clinical evaluation yielded the mean grip strength of (32.49±6.21) kg (80.8% of opposite side).The mean range of the wrist reached over 53% of the healthy side. Non-union and wound infection were not seen. The mean VAS scores had improved from 4.46±1.27 preoperatively to 1.31 ±0.95 postoperatively. The mean pain scores under stress had improved from 7.00±1.41 preoperatively to 2.62±1.26 postoperatively.There were remarkable differences between them. The mean Krimmer wrist score was 79. Conclusion Four-corner arthrodesis using NTMA-FCAC is an effective method for carpal collapse, preserving a majority of wrist function.

Biomechanic studies of Nitinol orthopedic instruments and their clini cal applications in hand surgery / 中华创伤骨科杂志

There has been great interest in NiTi alloy in medical domain si nc e Buehler found its memory effect in 1963. In the recent 30 years, a lot of basi c and clinical researches of the alloy have been reported in the world. From the biomechanical viewpoint, the ossification and resorption of bone are related to the stress. Different stresses are required in the different kinds of fracture healing. Many measurements have been used to test the biomechanical properties o f the Nitinol orthopedic instruments. The clinical applications of the instrumen ts in hand surgery started in China in 1980's and resulted in satisfactory outco mes. This article summarizes the progress made in the basic researches of the ni tinol orthopedic instruments and their clinical applications in hand surgery.