Anatomical and radiological considerations of the fifth metatarsal bone.

Twenty cadaver fifth metatarsals were harvested from cadaver feet. They were then sectioned coronally in three locations. The cortical thickness (medial, lateral, dorsal, and plantar) and the intra-medullary canal diameter (dorsoplantar and mediolateral) were measured at the three sectional sites. The intra-medullary canal of six specimens was outlined with radiopaque solder wire. The canal was then examined radiographically with the lateral and dorsoplantar views. A lateral bow on the dorsoplantar view was observed in some specimens, which could contribute to surgical complications. On lateral view the intramedullary canal appeared straight in all specimens. The canal projects at least partially into the fifth metatarsal cuboid joint. When considering intra-medullary fixation a surgeon must take into account quality of bone stock and bowing of the canal. A bowed intra-medullary canal lends to vulnerability of the medial cortex at roughly mid-shaft of the fifth metatarsal. The canal has a narrower diameter in the dorsoplantar dimension than the mediolateral dimension. The cortical thickness was found to be less in the dorsal and plantar areas of the fifth metatarsal when compared to medial and lateral cortex. All of these findings lead to causes for complication in intra-medullary fixation of the fifth metatarsal.

Radiographic evaluation of the calcaneocuboid joint: a cadaver study.

Eighteen cadaver feet were used for radiographic evaluation of the calcaneocuboid joint. The articular surface of the cuboid on all specimens was painted with a radiopaque material. Fractures and 1-mm step-off of the fractures were simulated in six specimens. The articular surface line and joint space could be visualized maximally on an oblique radiograph without overlapping structures. The oblique view is good for assessing the extent of the minor fracture-displacement, which is normally obscured by overlapping projections in dorsoplantar and lateral radiographs. If there is any doubt on the routine radiographs or any injury involving the calcaneocuboid joint, an oblique view of the foot should be performed. The early diagnosis and treatment of calcaneocuboid joint injuries may minimize development of posttraumatic degenerative arthritis.

Calcaneocuboid joint involvement in calcaneal fractures.

The charts and radiographs of 48 surgically treated patients who underwent surgery for calcaneal fractures (right in 25 patients, left in 22, and bilateral in 1) between 1987 and 1994 were retrospectively reviewed. Coronal computed tomographic scans alone were obtained in 33 patients, and both coronal and axial computed tomographic scans were obtained in 9 patients. Three fractures exiting close to the calcaneocuboid joint (CCJ), but not involving the joint, were excluded. Nineteen patients (38.7%) had involvement of the CCJ. The extension of the fracture to the CCJ was apparent in anteroposterior or oblique radiographs or both in 18 patients. There was intra-articular fracture displacement of < or = 1 mm in 6 patients, and 13 patients had a step or a gap of > or = 2 mm with or without angulation. Eleven patients had joint depression type fractures, 6 had tongue type fractures, and 2 had comminuted fractures. Extension of the calcaneal fracture into the CCJ was significantly more common with the joint depression type calcaneal fractures (chi-square test; P = 0.008). The coronal computed tomographic images showed significant lateral subluxation of posterior facet fragments in 8 patients and considerable comminution of the lateral calcaneal wall with or without lateral subluxation of posterior facet fragment in 10 patients. These patients also had CCJ involvement, thus establishing a strong correlation between lateral subluxation of the posterior facet fragment or comminution of the lateral calcaneal wall and CCJ involvement. CCJ involvement is more common with joint depression type fractures. Extension of the fracture line into the CCJ should be suspected in presence of significant lateral column comminution or lateral talar subluxation.

A pitfall of coronal computed tomographic imaging in evaluation of calcaneal fractures.

Computed tomographic (CT) coronal images of the posterior talocalcaneal joint were compared with lateral radiographic views and intraoperative findings in 35 patients with 36 intra-articular calcaneal fractures. The severity of articular incongruity and rotational displacement of the posterior facet fragment were not well appreciated in coronal CT images of nine patients, although Bohler and Gissane angles were significantly decreased in lateral radiographs. This disparity between the radiographic and coronal CT scans can be explained by the intraoperative finding of rotation of the fractured central or lateral portion of the convex posterior calcaneal facet along a horizontal axis in the coronal plane.

Posteromedial process fractures of the talus.

In this report, we present the diagnosis and clinical outcome of four patients with fractures of the posteromedial process of the talus. In two patients, the posteromedial process fracture was missed initially, which led to painful nonunions. One patient was treated with excision of a nonunion, and the other patient with a nonunion refused further surgery. Two patients underwent ORIF through a posteromedial approach. CT scans were useful in defining the fracture in all four patients. Cast treatment was recommended for displaced fractures or fractures without significant subtalar joint involvement. ORIF was recommended for displaced fractures with significant subtalar joint involvement.

Meniscal detachment to approach lateral tibial plateau fractures.

This retrospective study evaluated 18 patients in whom an extensile approach to the lateral tibial plateau involving anterior detachment and retraction of the lateral meniscus was used to improve visualization of the tibial articular surface. All patients in this study had a significantly comminuted tibial plateau fracture with a minimum articular depression of 10 mm. Four of the 18 patients had peripheral meniscal tears that were repaired at the time of tibial fixation. All patients had a minimum followup of 13 months. The average range of motion was 0 degrees to 117 degrees. None of the patients had evidence of meniscal symptoms. Functional evaluation revealed that 13 of the patients had an excellent result, 5 had a good result, and 1 a poor result. Five patients evaluated with arthroscopy showed complete healing of the anteromedial detachment site of the meniscus. Two of the 5 patients also had a meniscal repair that healed. For patients in whom there is significant comminution and depression of the lateral tibial plateau, this is a safe and effective method of treatment that provides excellent exposure of the articular surface to allow an accurate reduction.

Anatomic consideration in the anterior approach to the sacro-iliac joint.

Anatomical study of L4 nerve branch, L5 nerve root, and bony stock in the sacroiliac region was performed in cadaveric specimens to provide anatomical references for anterior fixation of the sacroiliac joint. At 1 cm intervals along the sacro-iliac joint, the distance to the lateral border of the L4 nerve branch (to the lumbosacral trunk) and the L5 nerve root was measured. Computed tomography scans and cadaveric sectioning of the sacro-iliac region were performed to evaluate the bony stock available for fixation and the optimal screw direction to prevent neurologic damage. At 4 cm above the pelvic brim, the L4 nerve branch was a mean distance of 23 mm medial to the sacro-iliac joint, whereas the L5 nerve root was 26 mm. At the pelvic brim, those distances decreased to 10 mm for both structures. Four centimeters cephalad to the pelvic brim, the AP dimension of Sl complex was decreased. Screws that were 1 cm medial to the Sl joint and directed posteriorly and parallel to the joint did not endanger neurologic structures. At four centimeters above the pelvic brim, there is less danger of neurologic injury; however, a decrease in sacral bony stock may affect fixation.

A study of effects of radiation on silicone prostheses.

Radiation effects on silicone gel and dose distribution of radiation through mammary prostheses were studied, with the following results: Silicone gel behaves like tissue. Half value thickness for silicone gel and water are almost the same (within experimental margin for error). Linear absorption coefficient for silicone gel and water are comparable (within experimental margin for error).