The short-term outcome of the modified Sauvé-Kapandji procedure regarding range of motion, carpal bone translation and bony shelf size.

The Sauvé-Kapandji (S-K) procedure is a common treatment for rheumatoid wrists, but in some cases severe bone destruction makes this operative modality difficult to perform, while also resulting in a poor outcome. A modified S-K procedure for these wrists has been reported, but the clinical outcomes of the modified procedure are unclear. This study evaluated 24 wrists in 20 patients who underwent the modified S-K procedure. The mean follow-up period was 34.5 months. The clinical assessments were range of motion, carpal bone translation and bony shelf size. The range of motion and carpal bone translation were similar to those produced by the S-K procedure. In regard to bony shelf size, wrists with an excessively large bony shelf tended to have a progression of carpal bone translation toward the palmar direction due to the residual malposition of the ECU tendon. The modified S-K procedure appears to be a safe and effective surgical alternative for the treatment of severely destroyed rheumatoid wrists. Although the modified procedure allows for the adjustment of the bony shelf size, it should not be used with wrists that have an excessively large bony shelf.

Measurement of bone electrical impedance in fracture healing.

BACKGROUND: Although external fixation is widely used for fractures and limb lengthening, evaluation of the time for removing the external fixator is dependent upon radiographic examinations and clinical findings, and a useful method has yet to be established clinically. This study aimed to measure the bone electrical impedance (Z values) non-invasively by using external fixation pins as electrodes, and clarify the relationship with bone union. METHODS: Thirty rabbits received the external fixation at the right tibia and were assigned to a control group (group C; n = 5) and a fractured group (group F; n = 25). Z values were measured once a week following surgery. The animals of group F were assigned to 5 groups (weeks 2, 3, 4, 5, and 6 after osteotomy, each n = 5). The resistivity (rho) of the electrical property between electrodes was measured prior to euthanasia, and fracture cross-sectional area (FrA) of the conduction pathway and maximum bending stress (Bmax) were measured following excision of the tibia. RESULTS: Although Z values in group F increased through 5 weeks after surgery, Z values in group C remained constant at 3 weeks, and significant differences were observed between groups at 4, 5, and 6 weeks. The rho values and FrA in group F decreased through 5 weeks; while Bmax increased, reaching a plateau at 5 weeks. CONCLUSIONS: Narrowing of conduction pathway due to the decrease in the contour of fracture area accompanying bone remodeling resulted in an increase of Z values. Both Z values and Bmax in group F reached a peak at 5 weeks, this was believed to be the optimal time for removal of external fixation. These results suggest that measurement of Z values makes it possible to evaluate bone union.

Evaluating bone union of distal radius fractures by measuring impedance values.

The measurement of impedance is a noninvasive and simple quantitative technique for evaluation of fracture healing. Fractures of the distal radius are the most common long bone fractures, accounting for approximately 20% to 25% of all acute fractures. External fixators have been applied clinically to treat unstable distal radius fractures. The evaluation of radiological findings and clinical signs are current standard methods and are effective in assessing fracture union of the distal radius, but these methods are dependent on subjective elements. For the objective methods, previous studies have shown that measurement of bone mineral density, ultrasound, quantitative computed tomography, and acoustic emission are useful in evaluating bone union. However, due to the complexity and high radiation dose associated with these methods, are seldom used clinically. This study was undertaken to examine the correlation between bone union and impedance at the site of digital radius fractures treated with an external fixator, using an alternating current electrical stimulator and a digital oscilloscope.

Efficacy of titanium dioxide photocatalyst for inhibition of bacterial colonization on percutaneous implants.

The purpose of this study was to evaluate the efficacy of titanium dioxide photocatalyst in inhibition of bacterial colonization on percutaneous implants. Titanium dioxide photocatalyst was prepared by direct oxidization of pure titanium substrate, and a comparative study with pure titanium was performed. The bactericidal ability of the photocatalyst was examined using methicillin-resistant Staphylococcus aureus (MRSA) suspensions in a colony-forming assay according to the Japanese Industrial Standards committee standard. After exposing the MRSA suspension on sample plates to ultraviolet A (UVA) light, the number of surviving bacteria was estimated. Next, an animal model for inhibition of colonization was examined in vivo. Pins were inserted into the femurs of rabbits, were infected with 10(8) colony-forming units of MRSA suspension, and were illuminated with UVA light for 60 min daily; the number of colonizing bacteria was estimated after 7 days. The bactericidal ability of the photocatalyst was apparent after 60 min, when the bacteria had almost disappeared. The number of colonizing bacteria on photocatalytic pins was decreased significantly in vivo. The photocatalyst was effective even against resistant bacterial colonization. Clinically, the incidence of percutaneous implant infection such as pin tract infection in external fixation could be reduced using the titanium photocatalyst.

Experience of bone bridge resection and bone wax packing for partial growth arrest of distal tibia.

Two patients with a partial growth arrest of the distal tibia were treated by bone bridge resection and bone wax packing technique. Their average age at the time of surgery was 7 years, both had been injured in an accident, and each had been treated with percutaneous pinning and a plaster cast. Unfortunately, partial growth arrest of the distal tibia occurred, and the ankle varus deformity gradually progressed. About 1 year after initial treatment, bone bridge resection and bone wax packing were performed. The average follow-up period was 80 months. There was no reformation of the bone bridge or recurrence of deformity, and gradual improvements in clinical and radiographic findings were observed. Although fat is typically used as an interpositional material after bone bridge resection, there are problems with its use, including a lack of hemostasis and the absence of intrinsic stability. Bone wax is readily available and commonly used in medical applications to control bleeding. It is considered a useful plug, it is inexpensive, and it is not associated with complications.