William P. Urban

Occult osteochondral lesions (bone bruises) have been documented on magnetic resonance images in more than 80% of patients sustaining acute anterior cruciate ligament ruptures. Despite the high prevalence of these lesions, little is known about the histologic changes in the adjacent articular cartilage. Ten patients with acute anterior cruciate ligament ruptures who had a preoperatively documented (by magnetic resonance imaging) geographic bone bruise at the sulcus terminalis on the lateral femoral condyle underwent a 3-mm diameter trephine biopsy of the articular cartilage and subchondral bone overlying the bone bruise at the time of anterior cruciate ligament reconstruction. Biopsy samples of the articular cartilage and subchondral bone were stained with hematoxylin and eosin and toluidine blue. All patients had significant arthroscopic and histologic articular cartilage irregularity in the area overlying the bone bruise. Arthroscopic findings of the articular cartilage included softening (dimpling), fissuring, or overt chondral fracture. Histologic examination revealed degeneration of the chondrocytes and loss of toluidine blue staining in the articular cartilage (loss of proteoglycan). There was necrosis of osteocytes in the subchondral bone, and empty lacuna were visible. This study defines the exact histologic changes of the articular cartilage overlying a geographic bone bruise secondary to an acute anterior cruciate ligament tear. Our findings suggest that a geographic bone bruise found on magnetic resonance imaging indicates substantial damage to normal articular cartilage homeostasis.

This investigation compared the maximum load at failure of BioScrew (Linvatec Corp, Largo, FL) and titanium alloy interference screw femoral fixation using a human cadaveric model that approximated the anatomical orientation and physiological strain rate of in vivo bone-patellar tendon-bone (BPTB) graft loading following anterior cruciate ligament reconstruction. Eighteen fresh-frozen human BPTB allografts (10-mm wide, 10-mm thick, 25-mm long bone plugs) with either BioScrew or titanium alloy (Ti 6A14V) screw (7 x 25 mm) fixation were compared for maximum load at failure at a strain rate of 20 mm/minute. Nine cadaver femurs with bone mineral densities of 0.88 +/- 0.18 g/cm2 (anterior/posterior) and 1.3 +/- 0.24 g/cm2 (lateral) received the allografts. No statistical differences were observed in maximum load at failure (P = .95) or failure mode (P = .11) between specimens fixed with either screw type. When biomechanically tested with anatomic orientation and at functionally relevant strain rates, the BioScrew provided maximum load at failure equal to a titanium alloy screw.

Abnormalities have been noted in the arterial pulse wave of human subjects with peripheral arteriosclerosis and with hypertension. The major change, diminution to disappearance of the dicrotic wave, has also been found in young diabetic subjects. The present study reports on the differences in the configuration of the arterial pulse wave of 162 diabetic subjects between the ages of 11 and 29 years and a comparable group of 275 nondiabetic controls. The findings seem to support the concept that the vascular abnormalities seen in diabetes mellitus are an integral part and not a complication of the disease.

This investigation attempted to determine the radiographic position of human meniscal horn bony insertion sites. This information would prove vital for anatomically correct osseous tunnel placement necessary for the restoration of a functional meniscus after reconstructive surgery. The native bony insertion sites of the medial and lateral meniscus in 13 fresh-frozen human cadaver knees were radiographically examined. After insertion site outline with 22-gauge fine wire, anteroposterior and lateral radiographs were obtained. Radiographic landmarks were then described in detail. Each meniscal horn was found to have a distinct bony insertion site with characteristic and consistent radiographic landmarks defining its margins. Using an arthroscopic guide, 3/32-inch fine wires were drilled into the center of the lateral (5 specimens) and medial (5 specimens) meniscal horns to validate these locations and to establish the clinical usefulness of these measures. Improved understanding of meniscal horn insertion site locations should improve osseous tunnel placements during meniscal transplantation. In the presence of a properly sized allograft, anatomically correct tunnel placement increases the likelihood of restoring normal meniscal function.