Anatomical Structures related to the Fixation Screw of Acetabular Cup in Total Hip Arthroplasty / 대한정형외과학회잡지

PURPOSE: This study was conducted to obtain anatomical data useful for transacetabular screw fixation in total hip arthroplasty. MATERIAL AND METHODS: Using 67 hemipelvises of Korean adults cadaver, the variations of external iliac vessels and obturator neurovascular bundle were observed. Forty-nine pelvises were used for the study of vulnerable structures to transacetabular screw inserted through 8 points and 25 pelvises for measuring the thickness of articular cartilage, cortical bone and cancellous bone at each screw penetration site. RESULT: The lengths of S-pin inserted at the inferior, posterior and posteroinferior portion of the acetabulum were more than 20mm. The length of entire bone and thickness of cortical bone measured at the mid point of the posterosuperior portion were longest. The external iliac vessels showed variations in their spatial relationship. At anterosuperior portion, the bone and muscle layer were very thin. The cortical bone of articular side became thicker from center to periphery. The thickness of cortical bone in the pelvic cavity showed different values at different sites. CONCLUSION: The authors suggest that the structural varieties can be injured when inserting the fixation screw of acetabular cup, and the thickness of cortical and cancellous bone may be useful in total hip replacement.

Optimal Orientation of the Femoral Tunnel in Reconstruction of Posterior Cruciate Ligament / 대한정형외과연구학회지

PURPOSE: We investigated the optimal orientation of femoral tunnel in PCL reconstruction. MATERIALS AND METHODS: Five cadaver knees were used for this study. We made the tibial tunnel at the center of foot-print of posterior cruciate ligament, at an angle of 45o to the long axis of the tibia using the Kirschner wire. The femoral tunnel was made 11mm posterior to the articular cartilage margin of medial femoral condyle. The orientation of the femoral tunnel was made on the expolated line between two points, namely the placement of the femoral tunnel on lateral wall of medial femoral condyle and the opening of the tibial tunnel in full extension of knee. We measured the angles between the tunnel and wire on roentgenogram which passed through the femoral and tibial tunnel. RESULT: On the anteroposterior view, the angle of the graft to the long axis of the femur became acute during flexion. The angle of the graft to the long axis of the femur on the coronal plane changed from 12.6o to 154.9o with flexion from 0o to 105o. The angle of the graft to the long axis of the femur on sagittal plane changed from 137.0o to 45.1o with flexion from 0o to 105o. These results suggest that optimal graft-tunnel divergence (GTD) is obtained when the angle of graft to the long axis of the femur are 83.8o on the coronal plane and about 91o on the sagittal plane. CONCLUSION: To obtain optimal orientation of the femoral tunnel, the opening of the femoral tunnel should be located as near as possible to the margin of the articular cartilage of the medial femoral condyle.

Intraosseous Epidermoid Cyst of Distal Phalanx: A case report / 대한정형외과학회잡지

Epidermoid cyst is a common skin lesion. However, in areas where the skin is tightly adherent to the bone, a portion of the epidermis may be implanted into the bone traumatically or a subcutaneous epidermoid cyst may penetrate the bone cortex. Intraosseous epidermoid cyst is rare, and arises almost exclusively in the skull and phalanges of the hand. In the hands, terminal phalanx is involved in almost all cases. Differential diagnosis includes glomus tumor with bone erosion, enchondroma, osteomyelitis, aneurysmal bone cyst and metastatic tumors. We experienced a case of intraosseous epidermoid cyst in the distal phalanx of a 28-year-old woman, who had injured her finger about 20 years ago. We report the clinical, radiographic and pathological findings in detail.