Hirohiko Azuma

The nerve endings of the acetabular labrum.

The nerve endings of the human acetabular labrum were investigated. Twenty-three acetabular labra were obtained from 24 fresh human cadavers, stained with Suzukis silver impregnation and an immunohistochemical technique for neurogenic specific protein S-100, and examined by light and electron microscopy. Ramified free nerve endings were seen in all specimens by silver staining, and also were observed by the immunohistochemical technique for S-100 protein. Sensory nerve end organs, such as a Vater-Pacini corpuscle, Golgi-Mazzoni corpuscle, Ruffini corpuscle, and articular corpuscle (Krause corpuscle), were observed by silver staining. Collagen fibers were scattered sparsely in the superficial layer of the labrum, and nerve endings were observed mostly in this region. Collagen fibers were sparse, and nerve endings also were observed in some regions among the collagen fiber bundles in the inner layer. Innervation of the acetabular labrum was confirmed in this study, suggesting that nerve endings in the labrum may be involved in nociceptive and proprioceptive mechanisms.

Morphology and Distribution of Nerve Endings in the Human Triangular Fibrocartilage Complex

We studied the morphology and distribution of nerve endings in the human triangular fibrocartilage complex using both silver staining and immunohistochemical staining using a protein specific to nerve fibres. Free nerve endings were found in the ulnar side of the triangular fibrocartilage complex, especially in the ulnar collateral ligament, meniscus homologue and the adjacent collagen fibre area of the peripheral part of the ulnar side of the articular disc. Meissner’s and Krause’s corpuscles were observed in the ulnar collateral ligament and meniscus homologue. The fact that free nerve endings were observed in the meniscus homologue and adjacent collagen fibre area of the peripheral part of the ulnar side of the articular disc suggests that this disc may be a source of wrist pain. The presence of nerve end bulbs in the triangular fibrocartilage complex also suggests a possible role for corpuscles as mechanoreceptors.

Preoperative and postoperative assessment of rotational acetabular osteotomy for dysplastic hips in children by three-dimensional surface reconstruction computed tomography imaging.

The three-dimensional relationship between the acetabulum and femoral head was evaluated using three-dimensional computed tomography (CT) reconstruction before and after rotational acetabular osteotomy. This method provides exact anatomic information on acetabular coverage so that precise operative planning is more easily made. Evaluation of six dysplastic hips indicated the possible dangers of anterolateral rotational shift of the acetabulum when there is marked posterior deficiency, such as in the case of a high decree of subluxated femoral head covered by a shallow false acetabulum. In these circumstances, it may be safer and preferable to plan a lateral shift instead of an anterolateral shift.

Case report 685

We report an unusual case of an ossifying tumor arising in the deep soft tissue adjacent to the humerus of a 72-year-old woman. The tumor exhibited sarcoma-like features histologically, although its clinical course unexpectedly differed from that of a malignant tumor. We diagnosed this particular case as an ossifying fibromyxoid tumor of soft parts, which has been recently described by Enzinger et al.. This is another example of an ossifying soft-tissue tumor which simulates a malignant sarcoma.

Trabecular microfractures in the acetabulum. Histologic studies in cadavers.

The distribution of trabecular microfractures was studied in 39 cadaveric acetabula. The mean age of the group with microfractures was 71 years and the mean age of the group without fractures was 60 years. Most of the microfractures were located at the subchondral, weight-bearing portion of the acetabulum. Our observations suggest that trabecular microfractures are involved in the formation of bone cysts.

Evaluation of acetabular coverage : three-dimensional CT imaging and modified Pelvic inlet view

The anterior and posterior coverages of the acetabula were evaluated by comparison of anterior edge-center-posterior edge (ACP) angle by modified inlet view and three-dimensional computed tomographic (3-D CT) images of the hip. Acetabular coverage in 3-D CT images was classified into three grades of front and rear views. The close relationship of this grading and the ACP angle was confirmed. Conventional radiographs with a modified inlet view are usually significant to evaluate the acetabular coverage, however, in the future, 3-D CT images will be routinely used in complicated hip surgery because they provide more detailed information to aid preoperative planning.

Melorheostosis of the hand: A report of two cases

Two cases of melorheostosis of the hand are reported. Histopathologic examination confirmed the characteristic x-ray findings and excluded other skeletal dysplasias, such as osteopoikilosis and osteopathia striata.

Avascular necrosis of the femoral epiphysis complicating a minimally displaced fracture of solitary bone cyst of the neck of the femur in a child. A case report.

Reported herein is a rare case of a patient with a pathologic fracture through a cyst in the femoral neck that resulted in avascular necrosis of the femoral epiphysis. This type of necrosis is commonly understood to follow displaced fractures of the femoral neck in children, but has also been reported to follow undisplaced fractures.

Anterior dislocation of the proximal fragment of a scaphoid fracture: A case report

A case of irreducible anterior dislocation of the proximal fragment of a scaphoid fracture without perilunate or lunate dislocation is described. This case is a subtle variation of transscaphoid fracture dislocation. The mechanism of injury of this entity is also discussed. Case Report

Osteosarcoma of the patella : a case report

A 34-year-old woman complained of pain and swelling in the left patella. Because of roentgenogram showed hardly any destruction of the patella, she was not initially treated for a bone tumor. The clinical course followed the initial symptoms of a respiratory disorder with pulmonary metastatic foci. A bone tumor was first suspected after aspiration cytology of a lung tumor mass. A left patellectomy was performed to relieve the pain and confirm the diagnosis. The pain was relieved by the operation, but respiratory failure set in and progressed rapidly. The patient died three days later. Histologic examination showed that the tumor tissue consisted of atypical cells, spindle to polygonal in shape. The marrow space of the patella was predominantly occupied by neoplastic cartilaginous tissue. The pathologic diagnosis was primary chondroblastic osteosarcoma of the patella.