Histological and molecular characterization of the femoral attachment of the human ligamentum capitis femoris.

The ligamentum capitis femoris (LCF) has increased in clinical significance through the development of hip arthroscopy. The histological pathologies and molecular composition of the femoral attachment of the LCF and the degeneration caused by LCF disruption were investigated in the human hip joint. Twenty-four LCFs were retrieved at surgery for femoral neck fracture (age range: 63-87 years). In the "intact" (i.e., intact throughout its length, n = 12) group, the attachment consisted of rich fibrocartilage. Fibrocartilage cells were present in the midsubstance. In contrast, the construction of the attachment in the "disrupted" (i.e., ligament no longer attached to the femoral head, n = 12) group had disappeared. The attachment in the disrupted group was not labeled for type II collagen or aggrecan, while that in the intact group was labeled for types I, II and III collagen, chondroitin 4-sulfate, chondroitin 6-sulfate, aggrecan, and versican. The percentage of single-stranded DNA-positive chondrocytes was significantly higher in the disrupted group than in the intact group. We conclude that the femoral attachment of the LCF has a characteristic fibrocartilaginous structure that is likely to adjust to the mechanical load, and suggest that its degeneration is advanced by disruption and should be regarded as a clinical pathology.

Arthroscopic drilling for the treatment of osteochondral lesions of the talus.

BACKGROUND: An osteochondral lesion of the talus is a relatively rare disorder of the ankle. While a number of treatment options have been reported, it appears to be difficult to manage all lesions with a single approach. We evaluated the indications for and the results of arthroscopic drilling for the treatment of an osteochondral lesion of the talus. METHODS: Eighteen ankles (seventeen patients) with a symptomatic osteochondral lesion of the talus were examined. The ages of the patients ranged from ten to seventy-eight years (mean, 28.0 years) at the time of the operation, and the patients were followed postoperatively for two to 9.5 years (mean, 4.6 years). After the continuity of the cartilage overlying the lesion and the stability of the lesion had been confirmed, arthroscopic drilling was performed with use of a Kirschner wire that was 1.0 to 1.2 millimeters in diameter. A cast was not applied postoperatively, and full weight-bearing was allowed six weeks after the procedure. RESULTS: The clinical result was good for thirteen ankles and fair for five; all ankles had improvement. Twelve of the thirteen ankles that were in patients who were less than thirty years old had a good result. In contrast, only one of the five ankles in patients who were fifty years old or more had a good result. Thus, the clinical results tended to be better for younger patients. Improvement was seen radiographically in fifteen ankles. However, the three ankles in patients who were more than sixty years old were found to have no improvement on radiographic examination. Analysis of the group of patients who had a history of trauma revealed that the mean interval between the injury and the operation was 6.3 months for the three ankles that had a good radiographic result and 11.3 months for the six that had a fair result. Thus, the radiographic results tended to be better when the interval between the injury and the operation was shorter. CONCLUSIONS: Arthroscopic drilling for the treatment of medial osteochondral lesions of the talus does not require osteotomy of the medial malleolus or postoperative immobilization; thus, the procedure is less invasive than other types of operative treatment for the condition and it allows early resumption of daily activities and sports. On the basis of the results in this study, we believe that the procedure is effective and useful in young patients, especially those who have not yet had closure of the epiphyseal plate. A specific indication for the procedure is an early lesion with only mild osteosclerosis of the surrounding talar bone, continuity of the cartilaginous surface, and stability of the osteochondral fragment.

Isolation and characterization of new peptide antibiotics, plusbacins A1-A4 and B1-B4.

New antibiotics, plusbacins A1-A4 and B1-B4, were isolated from the culture broth of a strain of Pseudomonas sp. These antibiotics were isolated as a complex by column chromatographies on Diaion HP-20 and silica gel, and then separated by HPLC. They are amphoteric in nature. The hydrochlorides are obtained as colorless powders, soluble in methanol and alkaline water. From their physico-chemical properties, these antibiotics are presumed to be acyloctapeptides containing a lactone linkage, and their differences occur in amino acid and fatty acid residues. The antibiotics are active against Gram-positive bacteria in vitro and in vivo.

Follow-up study of MRI for osteochondral lesion of the talus.

Characteristic MRI findings of osteochondral lesions of the talus have been reported. We examined how they change before and after treatment and discussed their significance. Twenty two ankles in 21 patients had MRI examination before and after treatment of the talar lesion. We evaluated the changes in the low intensity areas in T1-weighted image and the signal rims behind osteochondral fragment in T2-weighted image which have been reported as characteristic findings. Clinical symptoms were improved postoperatively in all subjects. The low intensity areas in T1-weighted image seen before the surgical treatment tended to decrease in size postoperatively. The low intensity area in T1-weighted image was reduced in 15 of the 22 ankles (68.2%). Low signal rim in T2-weighted image was seen in three cases before the treatment. All disappeared completely after arthroscopic drilling. Similarly, high signal rim in T2-weighted image seen in 13 cases before the treatment disappeared in 10 postoperatively. These findings were considered indicative that surgical treatments reduced abnormal stress of the underlying bone element due to unstable osteochondral fragment, leading to reduction of the low intensity area. The disappearance of signal rims in T2-weighted images was considered to indicate obliteration of the interface between the osteochondral fragment and the talar bed with bone union. We believe that MRI of the osteochondral lesion of the talus will be useful for postoperative evaluation allowing assessment of the need for further treatment. The decreasing size of low intensity areas in T1-weighted images and disappearance of signal rims behind the osteochondral fragment in T2-weighted images suggested healing of the osteochondral lesions.

Histopathological study of nonosseous tarsal coalition.

Histopathological analysis was performed on 55 feet in 48 patients with nonosseous tarsal coalitions. Histological findings were similar to those observed at the tendinous attachment site of Osgood-Schlatter disease, accessory navicular, and bipartite patellae. No nerve elements were observed in the fibrocartilaginous tissue at the coalition. Nerve elements were present only in periosteum and articular capsule surrounding the coalition. Pain in the tarsal coalition is not mediated by nerve elements at the coalition site itself. It is assumed that the pain is caused by mechanical abnormality that results from incomplete coalition. Incomplete coalition produces microfractures and remodelings on the boundaries between bone and the coalition, which then lead to degenerative changes. This mechanical abnormality seems to induce pain via free nerve endings in the periosteum and in the articular capsule surrounding the coalition.

Regional variations in human patellar trabecular architecture and the structure of the proximal patellar tendon enthesis.

Proximal patellar tendinopathy occurs as an overuse injury in sport and is also characteristic of ankylosing spondylitis patients. It particularly affects the posteromedial part of the patellar tendon enthesis, although the reason for this is unclear. We investigated whether there are regional differences in the trabecular architecture of the patella or in the histology of the patellar tendon enthesis that could suggest unequal force transmission from bone to tendon. Trabecular architecture was analysed from X-rays taken with a Faxitron radiography system of the patellae of dissecting room cadavers and in magnetic resonance images of the knees of living volunteers. Structural and fractal analyses were performed on the Faxitron digital images using MatLab software. Regional differences at the enthesis in the thickness of the uncalcified fibrocartilage and the subchondral plate were evaluated histologically in cadaveric material. The radiological studies showed that the quantity of bone and the apparent trabecular thickness in the patella were greatest medially, and that in the lateral part of the patella there were fewer trabeculae which were orientated either antero-posteriorly or superiorly inferiorly. The histological study showed that the uncalcified fibrocartilage was most prominent medially and that the subchondral plate was thinner laterally. Overall, the results indicate that mechanical stress at the proximal patellar tendon enthesis is asymmetrically distributed and greater on the medial than on the lateral side. Thus, we suggest that the functional anatomy of the knee is closely related to regional variations in force transmission, which in turn relates to the posteromedial site of pathology in proximal patellar tendinopathy.