Histomorphometric study of femoral heads in hip osteoarthritis and osteoporosis.

During the period from 2000 to 2003, ninety eight samples of femoral heads were collected. In these pieces, two zones were analyzed: a high-load zone (the hard core of the head) and a low-load zone (the round ligamentum teres zone). As control group, 6 femoral heads (3 of women and 3 of men), proceeding from autopsy in peoples without pathological antecedents and youngs, were studied. After the samples had been embedded in methylmethacrylate and stained, they were subjected to an histomorphometric study. By means of histomorphometry, trabecular bone volume (TBV) and osteoid substance (OSV) was determined. Statistically significant differences were found as for peripheral osteoid volume (low-load zone) (p=0.036) and trabecular bone volume, both peripheral and central. Both volumes decreased in osteoporotic samples and in those from women (p=0.000), in comparison with control group. Regarding the relationship between the high-load and low-load zone, significant data were obtained. The high-load zone had a greater trabecular bone volume than the low-load zone, regardless of the pathology and sex, but this increase was more pronounced in the arthrosic samples and in those from men. Additionally, this trabecular bone volume in the high-load zone decreased with increasing age of the donor (p=0.037), when the control group is compared. In sum, we observed a reduction in the formation of TBV and OSV in osteoporosis but also a decrease in the arthrosic, in samples from older subjects, in women, and in the low-load zone of the samples, when the control group is compared. These data suggest the coexistence of both pathologies, which is more pronounced in older subjects and women.

Biological response of new activated acrylic bone cements with antiseptic properties. Histomorphometric analysis.

The biological response to an acrylic bone cement cured with 4,4'-bis-dimethylamino benzydrol (BZN) as activator of reduced cytotoxicity and antiseptic properties, has been carried out and compared with that obtained for CMW 3 cement. Histomorphometrical data (undecalcified trichromic Goldner staining) were obtained by measuring the most significant variables at the bone-cement interface. Quantitative results of tissue response revealed that newly formed bone and connective tissue were maximum at 4 weeks whereas bone marrow increased with time of implantation for both cements. Statistical analysis (p < 0.05) showed no significant differences in newly formed bone and bone marrow with time and between both groups, however, connective tissue significantly decreased between 4 weeks and 12 weeks for BZN cement, and between 12 weeks and 24 weeks for CMW3. By comparing both cements at each time, lower significant percentage of connective tissue at the bone-cement interface of the BZN cement, was obtained at 12 and 24 weeks, however, a very low amount of connective tissue was found for both cements. All the results indicate that the new activated system could be applied clinically in a relatively short time, after the corresponding preclinical study.

Pulsed electromagnetic fields induce peripheral nerve regeneration and endplate enzymatic changes.

An experimental study was carried out in rats with the purpose of demonstrating the capacity of pulsed electromagnetic fields (PEMFs) to stimulate regeneration of the peripheral nervous system (PNS). Wistar and Brown Norway (BN) rats were used. Direct sciatic nerve anastomoses were performed after section or allograft interposition. Treatment groups then received 4 weeks of PEMFs. Control groups received no stimulation. The evaluation of the results was carried out by quantitative morphometric analysis, demonstrating a statistically significant increase in regeneration indices (P < 0.05) in the stimulated groups (9000 +/- 5000 and 4000 +/- 6000) compared to the non-stimulated groups (2000 +/- 4000 and 700 +/- 200). An increase of NAD specific isocitrate dehydrogenase (IDH) activity was found along with an increase in the activity of acetyl cholinesterase at the motor plate. The present study might lead to the search for new alternatives in the stimulation of axonal regenerative processes in the PNS and other possible clinical applications.

Injectable self-curing bioactive acrylic-glass composites charged with specific anti-inflammatory/analgesic agent.

Injectable bioactive acrylic formulations based on poly(methyl methacrylate) (PMMA) and different amounts of bioactive glasses in the system SiO2-CaO-Na2O-P2O5 have been prepared in the presence of the anti-inflammatory analgesic drug fosfosal, the sodium salt of 2-phosphonoxibenzoic acid, to be used in minimally invasive surgery. The injectability of the formulations evaluated according to the established protocol was around 80%. The experimental formulations provided maximum temperatures in the range 50-60 degrees C, which were lower than those of commercial acrylic bone cements currently used in percutaneous vertebroplasty (PVP). Residual monomer content of any formulation was inferior to 5%. Compressive yield strength of dry specimens was in the range 80-95 MPa, but it decreased after immersion in SBF to values in the range 30-50 MPa, due to the dissolution of the bioactive glasses and the drug in the medium. The release of fosfosal was evaluated in vitro (pH = 7.0). The release profile against time obtained from a PMMA cement was quasi-linear and the 80% of the initial amount of drug was released in 175 h. However, for bioactive cements, the 80-100% of the fosfosal charged was released in approximately 48 h, due to the dissolution of the glasses in the medium. Values of weight loss of the cements determined gravimetrically ranged between 16% and 26% depending on the initial amount of fosfosal, i.e. 20 or 30 wt%, respectively. The weight loss and the water uptake were simultaneous processes, and values of hydration degree were around 10-14%. The formation of an apatite-like layer was detected on the surface of the cements at different periods of time depending on the composition of the bioactive glasses. The cements containing the glasses with P2O5 produced the growth of the apatite layer in shorter periods of time. The presence of fosfosal accelerated the precipitation of this layer independently on the glasses. The in vivo biocompatibility studied by intramuscular implantation in rats showed the absence of an anti-inflammatory response and a fibrous layer around the implant for the cement prepared with PMMA/fosfosal which is attributed to the therapeutic action of fosfosal acting in situ. The response to cements prepared with bioactive glasses and fosfosal showed a mild inflammatory reaction with the formation of the typical fibrous capsule around the implanted material.

Biocompatibility and other properties of acrylic bone cements prepared with antiseptic activators.

Acrylic bone cements prepared with activators of reduced toxicity have been formulated with the aim of improving the biocompatibility of the final material. The activators used were N,N-dimethylaminobenzyl alcohol (DMOH) and 4,4'-dimethylamino benzydrol (BZN). The toxicity, cytotoxicity, and antiseptic action of these activators were first studied. DMOH and BZN presented LD50 values 3-4 times higher than DMT, were less cytotoxic against polymorphonuclear leucocytes, and possessed an antimicrobial character, with a high activity against the most representative microorganisms involved in postoperative infections. The properties of the acrylic bone cements formulated with DMOH and BZN were evaluated to determine the influence of these activators on the curing process and the physicochemical characteristics of the cements. A decrease of the peak temperature was observed for the curing with DMOH or BZN with respect to that of one commercially available formulation (CMW 3). However, residual monomer content and mechanical properties in tension and compression were comparable to those of CMW 3. The biocompatibility of acrylic bone cements containing DMOH or BZN was studied and compared with CMW 3. To that end, intramuscular and intraosseous implantation procedures were carried out and the results were obtained from the histological analysis of the surrounding tissues at different periods of time. Implantation of rods of cement into the dorsal muscle of rats showed the presence of a membrane of connective tissue, which increased in collagen fibers with time of implantation, for all formulations. The intraosseous implantation of the cements in the dough state in the femur of rabbits, revealed a higher and early osseous neoformation, with the presence of osteoid material surrounding the rest of the cured material, for the cement prepared with the activator BZN in comparison with that obtained following the implantation of the cement cured with DMOH or DMT (CMW 3).

Periosteal ganglion in a child.

A case of periosteal ganglion in a 10-year-old boy is reported. The diagnosis of periosteal ganglion was made on roentgenographic and MR appearance and histologic evidence. The patient was successfully treated by excision. The follow-up examination showed no recurrence. Periosteal ganglia must be considered a cause of expanding cortical erosions. This lesion may mimic other peripheral expanding lesions.

Distal vascular pedicle-hemisoleus to tibial length ratio as a main predictive index in preoperative flap planning.

The management of severe compound tibial fractures is aimed at obtaining osseous consolidation, proper cutaneous and muscular cover, absence of infection and restoration of limb function. A knowledge of the cutaneous and muscular vascularisation allows the surgeons to use many flaps in a rational and predictable manner. One of the most commonly used flaps is the soleus muscular flap. This may be used as a proximally or distally based muscular flap and the use of a hemisoleus flap has also been described. A morphometric analysis of the relation between tibial length and soleus vascular pattern provides a simple and reliable method for planning this flap preoperatively. The study was performed on fresh and preserved cadavers.

Osteochondral allografts for osteochondritis dissecans and osteonecrosis of the femoral condyles.

Osteochondral allografts were used in 11 patients with osteochondritis dissecans and 4 with osteonecrosis of the femoral condyles. The lesions were mainly in the medial condyle in 13 cases, and in the weightbearing area in 10. The grafts had a mean size of 6 cm2; 8 were kept in hypothermia at 4 degrees C for less than 24 h and 7 were stored at -80 degrees C with cryoprotection. After an average follow up of 3.2 years, only 2 patients needed a further operation, one for nonunion and the other for a fracture of the graft. The others had improved clinically and showed radiological union of the graft with preservation of the joint space.

Internal fixation of ulnar fractures by locking nail.

Fractures and dislocations of the forearm are commonly observed in trauma clinics. With time, there will probably be significant increases in fractures of the forearm associated with traffic and sports. The efficacy of the treatment of ulnar fractures by a new locking nail, developed by Lefevre in Strasbourg, was tested in 20 patients. The fractures were severely displaced ulnae or both bones of the forearm. The minimum follow-up period was six months. The average age of the patients was 33.5 years (range, 14-77 years). The nail is placed into the ulna proximally. Locking is achieved by two screws placed at the proximal and distal end of the nail. The healing time for the fractures of both bones of the forearm ranged from 75 days to 20 weeks, with an average of 15 weeks. Healing time for the ulnar fractures ranged from eight to 20 weeks, with an average of ten weeks. The advantages of this nail were easy closed technique, compression effects at the fracture site, and enough stability so that an external support and tourniquet, in isolated ulnar fractures, were not necessary.