Should calcaneal fractures be treated surgically? A meta-analysis.

A MEDLINE search from 1980 through 1996 revealed 1845 articles dealing with calcaneal fractures. Six of these articles that compared operative versus nonoperative treatment for displaced calcaneal fractures met the minimum criteria for inclusion in a meta-analysis. A statistical summary of information across the six articles revealed a trend for surgically treated patients to be more likely to return to the same type of work as compared with nonoperatively treated individuals. There also was a trend for nonoperatively treated patients to have a higher risk of experiencing severe foot pain than did operatively treated patients. Unfortunately, none of the other outcomes could be summarized formally across studies using statistical techniques because of variability in reporting across studies. Although the tendency was always for operatively treated patients to have better outcomes (reaching statistical significance in some of the articles), the strength of evidence to recommend operative treatment for displaced intraarticular calcaneal fractures remains weak. A large prospective randomized controlled trial should be able to answer this question.

Computer-aided pedicle screw placement using frameless stereotaxis.

STUDY DESIGN: In vitro assessment of accuracy and reliability of frameless stereotaxis for insertion of pedicle screws in human cadaveric lumbar spine. OBJECTIVES: To assess a new method of targeting and placing pedicle screws in a human cadaver study. SUMMARY OF BACKGROUND DATA: Pedicle screw instrumentation is common. Complications may occur from improper placement of screws. Even when performed by experienced spinal surgeons, improper placement can occur in 5.2% of pedicles instrumented. Development of computer-guided methods of pedicle screw insertion may decrease this complication rate. METHODS: The technique used preoperative computed tomography scans together with a commercial neurosurgical navigational computer system to assist in placing guidewires in the pedicles. A section of human cadaver spine was first scanned and the data transferred to the workstation. The image data set and physical specimen were then registered by using an instrumented articulated arm to identify selected points on the specimen and randomly sample surface points. Eight highly repeatable locations on each vertebral body were found to be suitable for registration, but better overall accuracy was obtained when surface matching was used in combination with these points. Under guidance of image on the computer, Kirschner wires were inserted into the pedicles of four vertebral bodies. The spine was rescanned, and the planned and resulting positions of the wires compared. RESULTS: The average distance between the planned and resulting wire entry point was 1.2 mm, with an average difference in planned and resulting trajectories of 6.0 degrees. CONCLUSIONS: Computer-aided pedicle screw instrumentation is feasible. Further technical points require clarification before widespread use is possible.

The excimer laser in orthopaedics.

This review details clinical and laboratory experience with the 308 nm XeCl excimer laser. This ultraviolet laser is not approved yet for use in arthroscopy, but has been shown to be extremely proficient for debridement of degenerate articular cartilage and meniscus. It has fewer advantages than conventional techniques for synovectomy, meniscectomy, and lateral release. Preliminary in vitro and in vivo studies were performed to investigate the character of laser-irradiated articular cartilage and to search for evidence of regeneration. A model of arthritis was created in rabbits to test the effects of the laser. Partial-thickness cuts in articular cartilage also were irradiated to test for cartilage regeneration. In vitro results indicated that the cartilage was sealed, with only a negligible loss in thickness. The results of live rabbit studies initially showed a similar sealing under scanning electron and light microscopy; however, it tended to break down in time. The results of autoradiographic and histologic studies showed no evidence of cartilage regeneration. Recent evidence suggests that the laser may adversely affect chondrocyte vitality in a region beyond the region of visible damage. There is no evidence to suggest that the laser is mutagenic.