Bone defects following curettage do not necessarily need augmentation.

BACKGROUND AND PURPOSE: The natural pattern of bone healing in large bony defects following curettage alone as treatment of benign bone tumors around the knee is not well reported. We analyzed the outcome in 146 patients. PATIENTS AND METHODS: 146 patients with over 18 months of follow-up who underwent curettage without bone substitute filling or bone grafting for a benign tumor in the distal femur or upper tibia were included. The mean diameter of the defects following curettage was 5.7 (1.3-11) cm and the estimated average volume was 63 (1-240) cm(3). The plain radiographs before and following curettage were reviewed to establish the size of the initial defect and the rate of reconstitution and infilling of the bone. The time to full weight bearing and any complications were recorded. RESULTS: There was a variable rate of infilling; some defects completely reconstituted to a normal appearance while some never filled in. In 88% of the cases, no further intervention after curettage was required and the mean time to full weight bearing was 6 weeks. The risk of subsequent fracture or the late development of osteoarthritis was strongly related to the size of the cyst at diagnosis, with cysts of > 60 cm(3) (about 5 cm in diameter) having a much higher incidence of complications. INTERPRETATION: This study demonstrates the natural healing ability of bone without any adjuvant filling. It could be used as a baseline for future studies using any sort of filling with autograft, allograft, or bone substitute.

Pulse-lavage washing is an effective method for defatting of morselized allograft bone in the operating theater.

BACKGROUND AND PURPOSE: Incorporation of fresh-frozen allograft bone and safety aspects associated with this procedure can be improved by removing blood and lipids from the bone. We investigated in a quantitative manner how efficient pulse lavage might be for removal of adipose tissue from morselized allograft bone. METHODS: Depending on the study, the washing was performed with an average of 0.8 L or 1.6 L of sterile saline at room temperature. Fat content of the morselized bone samples was determined using hexane elution. The efficiency of pulse lavage alone was compared with that after an additional wash in 12 L of warm water (55 degrees C). Unprocessed controls were also included for comparison. RESULTS: Pulse lavage with 0.8 L saline alone removed 80% of the fat from the bone, whereas 95% of the fat was removed when washing was performed with 1.6 L of saline. The cleansing efficacy was improved further when an additional wash with warm water was used. INTERPRETATION: Our results indicate that pulse-lavage washing alone at room temperature is an effective method for defatting of morselized allograft bone, but an additional wash with warm water improves the cleansing efficiency. Pulse lavage is easily available and simple to use in the operating theater.

The effect of chemical cleansing procedures combined with peracetic acid-ethanol sterilization on biomechanical properties of cortical bone.

Peracetic acid-ethanol sterilization (PES) with a preceding delipidation step is an effective sterilization method for allograft bone, but its influence on biomechanical properties of bone has not been studied. The aim of this study was to evaluate the effects of different incubation times of water, hydrogen peroxide and alcohol cleansing procedures combined with PES on biomechanical properties of freeze-dried cortical bone. These effects were studied by performing three-point bending tests on cortical samples. The lyophilized cortical samples were rehydrated prior to mechanical testing. The bending strength and the absorbed energy of the processed cortical samples were increased slightly but the Young's modulus was decreased compared to unprocessed samples. However, when the residual moisture content of the processed cortical samples was reduced from <5% to 0% all the biomechanical properties studied were significantly decreased. Hexane elution was used to determine the residual fat content of the processed cortical bone. Reducing the incubation time in cleansing had no effect on the residual fat content of the bone samples. Our in vitro study indicates that the cleansing procedure proposed combined with PES affects the biomechanical properties of cortical bone only on a limited scale.

Lipid oxidation may reduce the quality of a fresh-frozen bone allograft. Is the approved storage temperature too high?

BACKGROUND: International standards indicate that bone allografts for human use should be stored in a -40 degrees C or colder environment and the storage time should be up to 5 years. Bone allografts contain lipids which oxidate and become toxic with time. MATERIAL AND METHODS: We determined lipid oxidation in femoral head bone allografts by headspace gas chromatography at different storage temperatures and storage times. RESULTS: We found that lipid oxidation in fresh-frozen bone allograft was influenced by storage temperature and storage time. Lipid oxidation was significantly more rapid at -30 degrees C than at -70 degrees C. Even at -70 degrees C, however, some oxidation occurred but it was quite minimal after 3 years. INTERPRETATION: Because of the negative effects of lipid oxidation, we recommend a storage temperature of -70 degrees C or lower for bone allografts.

Inhibition of matrix metalloproteinase-14 in osteosarcoma cells by clodronate.

BACKGROUND: Bisphosphonates reduce the bone metastasis formation and angiogenesis but the exact molecular mechanisms involved are unclear. Progelatinase A (proMMP-2; 78 KDa) is activated up during the tumor spread and metastasis by a cell surface-associated matrix metalloproteinase (membrane-type matrix metalloproteinase [MT1-MMP] or MMP-14). MATERIAL AND METHODS: We evaluated the effects of a bisphosphonate (clodronate) on MT1-MMP mRNA expression and protein production, catalytic activity and proteolytic activation of proMMP-2 by cultured human MG-63 osteosarcoma cells. RESULTS: Clodronate, at therapeutically attainable noncytotoxic concentrations, dose-dependently inhibited phorbol myristic acetate (PMA)-induced proteolytic activation of proMMP-2 by human MG-63 osteosarcoma cells. Clodronate also downregulated the PMA-induced expression of MT1-MMP mRNA and protein production in human MG-63 osteosarcoma cells, as evidenced by Northern analysis and fluorescent immunohistochemistry. Furthermore, clodronate inhibited directly and dose-dependently MT1-MMP activity, and the MT1-MMP inhibition by clodronate was reduced in the presence of an increased (5 mM) Ca(2+) concentrations when compared to physiological (1 mM) Ca(2+) concentrations. CONCLUSION: We conclude that (1) the extracellular/cell-associated mechanism of bisphosphonate involves inhibition of MT1-MMP catalytic activity eventually by chelation, and that (2) intracellular mechanism involves downregulation of induced MT1-MMP mRNA and protein expression. The inhibition and downregulation of MT1-MMP by clodronate can be related to their ability to reduce MG-63 osteosarcoma cell invasion and spread. These findings may, at least in part, explain at molecular level the antitumor and antibone resorption activities of clodronate observed in clinical studies.

The real contamination of femoral head allografts washed with pulse lavage.

At the Tampere Bone Bank, all the discarded femoral heads from September 1997 to May 2000 were recultured. The grafts had been washed with pulse lavage at harvesting. 48 grafts had been discarded because of a positive culture and 85 with negative cultures because of positive or insufficient serological information. The femoral heads were split into halves, which were recultured as a whole in thioglycolate broth for 14 days. The contamination of previously culture positive and negative femoral heads did not differ. In only 2 cases did we find the same type of bacteria in the primary as in the new culture. Most of the primary contamination proved to be false positive. The real contamination seems to be very low, at least after pulse lavage washing of the femoral head.

Pancreatic pseudocystportal vein fistula manifests as residivating oligoarthritis, subcutaneous, bursal and osseal necrosis: a case report and review of literature.

Pseudocyst is a common complication of pancreatitis. Pseudocyst may rupture into the surrounding organs. Rupture into the portomesenteric vein is extremely rare with only seven cases being described in the English literature. pancreatic portal vein fistula is very difficult to verify. The aim of this study was to view the diagnostic methods of pancreatic portal vein fistula and to describe the results of high-dose corticosteroid treatment to our knowledge for the first time. We report here a case of pancreatic portomesenteric vein fistula that was manifest as subcutaneous fat necrosis, bursal necrosis, intramedullary aseptic bone necrosis and recidivating oligoarthritis. The literature of this unusual complication is reviewed. The results of high-dose corticosteroid treatment are also described. In patients with recidivating oligoarthritis, subcutaneous, bursal or osseal necrosis a pancreatic process should be included in the differential diagnosis even in cases of no abdominal signs or symptoms or previous abdominal history. Operative exploration of the pancreas should be performed in the early phase of the disease. To diminish the ongoing extrapancreatic manifestations after the closure of the fistula massive corticosteroid treatment may be attempted although the role of this therapy remains controversial.