Introduction: The confocal laser-scanning microscope (CSLM) was recently introduced. We have invented a new transmission type of double pass CSLM. This study is the first report of valuable pathological information related to bone tumor being derived using such microscopy.

Methods: The most remarkable characteristic of this microscope is the use of two laser beams twice passing through the specimen. This laser microscope can detect signals from coloring sources such hematoxylin eosin (HE) stain and obtain clear images of the organelles. The images presented here were built up as electronic signals, processed by computer analysis, and stored in frame memory. Specimens of the giant cell tumor stained with HE were examined directly by the phase contrast mode of this microscope and computer analysis was performed. Double pass CSLM and conventional microscopic views were then compared.

Results: We successfully observed sharply and sensitively positive fine granules in our laser microscopes provided higher magnification, resolution and contrast than did conventional ones. CSLM provides high magnification, contrast, resolution and can be used to observe living cells in culture in real time. With the combination of double pass CSLM and computer analysis, clear images of the subcellular organelles of various cells were successfully visualized.

Conclusion: This study suggests that double pass CSLM is an important tool for analyzing the cellular ultrastructure, physiology, and function of bone tumor. Double pass CSLM is also a powerful new instrument for orthopedics, complementing light and electron microscopy.

The Os subfibulare, or round ossicles at the tip of the lateral malleolus, are often regarded as accessory bone. Some patients with such fragments, however, complain of ankle pain and repeated sprain. This study addresses whether these fragments are unnecessary and ignorable?

Materials and method: From 1986 to 1998, we treated 54 ankles in 52 patients surgically. The average age at surgery was 18 years; the mean follow up period was 4.7 years. The whole the fragment was fixed to the lateral malleolus using a tension band.

Results: Each fragment was attached to at least one ligament. We classified these attachments as follows:

Type I a: only ATFL was attached to one fragment

There were 7 Type I a, 37 Type I b, 6 Type I c, and 4 Type II. Fifty-one ankles (94%) developed bony union and three united fibrously. The talar tilt was restored from 9.8 to 4.7 degrees after surgery. The American Orthopaedic Foot and Ankle Societyñs clinical rating system for the ankle-hindfoot improved from 77 to 98 and ankle pain decreased dramatically.

Conclusion: The fragment at the tip of the lateral malleolus is the origin site of the lateral ligaments. This fragment can be united with the lateral malleolus. We believe that the fragments are keystones of the lateral ankle ligament complex.