Displaced bucket handle tears of the medial meniscus masking anterior cruciate deficiency

Traditionally, anterior cruciate ligament (ACL) injuries have been difficult to diagnose in the Casualty Department. Studies have shown that the anterior drawer test has a poor sensitivity both in acute and chronic ACL deficient knees [4, 6, 9]; thus, more emphasis has been placed on the pivot shift and Lachman tests [3]. We report four cases of proven ACL rupture where clinical examination revealed an absent pivot shift and a near normal Lachman test following a displaced bucket handle tear of the medial meniscus. This finding has been reproduced in cadaver studies, and we conclude that if the history strongly suggests an ACL injury and examination reveals a stable knee, then the dual pathology of medial meniscus tear and ACL rupture should be suspected.     

Healing bone using recombinant human bone morphogenetic protein 2 and copolymer

Middiaphyseal 2.5-cm segmental defects in the right femurs of 12 sheep were stabilized with stainless steel plates and implanted with (1) 2 mg recombinant human bone morphogenetic protein 2 and poly[D,L-(lactide-co-glycolide)] bioerodible polymer with autologous blood (n = 7), (2) 4 mg recombinant human bone morphogenetic protein 2 and poly[D,L-(lactide-co-glycolide)] and blood (n = 3), or (3) poly[D,L-(lactide-co-glycolide)] and blood only (n = 2). Bone healing was evaluated for 1 year using clinical, radiographic, gross pathologic, and histologic techniques. Union occurred in three sheep in Group 1, two in Group 2, and none in Group 3. In the animals that healed, new bone first was visible radiographically between Weeks 2 and 6 after implantation; new bone mineral content equaled that of the intact femur not surgically treated by Week 16; recanalization of the medullary cavity approached completion at Week 52; and at necropsy the surgical treated femurs were rigidly healed, the poly[D,L-(lactide-co-glycolide)] was resorbed completely, and woven and lamellar bone bridged the defect site. In two Group 1 sheep euthanized at Weeks 2 and 6, polymer particles were permeated by occasional multinucleated giant cells. Some plasma cells, lymphocytes, and neutrophils were present locally. The poly[D,L-(lactide-co-glycolide)] tended to fragment during surgical implantation. Despite these observations, the recombinant human bone morphogenetic protein 2/poly[D,L-(lactide-co-glycolide)] implant was able to heal large segmental bone defects in this demanding model.     

Biologic attachment of an allograft bone and tendon transplant to a titanium prosthesis

An Achilles tendon allograft with its bony insertion was used to bridge a Titanium implant, containing an endoprosthetic tendon anchor, and the sheep biceps muscle. Twelve sheep were operated on unilaterally and followed up clinically and histologically for 2, 4 (n = 2), 8, and 12 months (n = 4). Full function of the front limb was regained after 8 to 12 weeks. There were no signs of mechanical loosening at all times. The morphologic changes at the bone block and implant fixation site were an initial revascularization of the allograft bone, which was observed at 2 months and enhanced at 4 months but occurred without any evidence of bone remodeling. This was changed in all specimens taken at 8 and 12 months where intensive new bone development, remodeling, and bone ingrowth in the titanium implant was found. Bone mass was shifted significantly to the tendon insertion half of the bone block because of a creeping substitution of the cancellous allograft bone and bone ingrowth to the implant. Overall bone mass slightly decreased with time but resorption of allograft bone outweighed new bone development only at lesser loaded areas. Transplantation of a bone and tendon allograft to an implant resulted in a revitalized, mechanically stable, and biologically anchored compound.     

Evaluation of the use of tannic acid in preparation of the rabbit knee meniscus for scanning electron microscopy

The femoral faces of medial and lateral menisci of the rabbit knee were structurally reinforced with tannic acid and studied using the scanning electron microscope. Significant improvement in preservation of the meniscal surfaces, as compared to previous studies, was brought about by the structural reinforcement technique. Menisci, although detacted from tibial plateaux, retained well their shape, dimensions, and microarchitecture. Differences in surface morphology between medial and lateral menisci and between longitudinal sectors on menisci were recorded. Appearances of surface irregulatities were reduced to a very low level, and the possibility that this minimum exists in situ is forwarded.     

Preimplant guided bone regeneration in the anterior maxilla

Guided bone regeneration is a clinical procedure aimed at promoting bone formation at sites where there is severe bone loss. The purpose of this article was to demonstrate reconstruction of deformations of the alveolar process resulting from traumatic injuries to maxillary incisor teeth by guided bone regeneration procedures followed by insertion of dental implants. In both cases, submembranous space-making was stabilized by human demineralized freeze-dried bone. Implant insertion at the sites of bone augmentation resulted in successful restorations. Histologic examination of biopsy samples from the submembranous hard tissue revealed particles of demineralized freeze-dried bone allografts partially surrounded by uninflamed connective tissue and by vital bone adjacent and adhered to the demineralized freeze-dried bone allograft particles.     

Healing of osseous submucous cleft palates with guided bone regeneration

Two methods for estimation of plasmid loss rates were tested on data obtained from traditional (serial transfer) stability experiments. The first method was based on the assumption that the plasmid does not inhibit the growth of its host, whereas the second method takes differences in the interdivision time of plasmid-free and plasmid-carrying cells into account. In the cases where the loss rate is high and the plasmid does not exert strong growth inhibition, the estimates appear very reliable. When the plasmid loss rate is small and the plasmid exerts inhibition of growth to its host, the experimental design becomes unreliable.     

Repeated bone repositioning in the growing rabbit calvarium hampers bone segment incorporation

There has been concern among surgeons that multiple extended craniofacial procedures might be detrimental to the viability of the involved skeletal structures. This study aimed to explore the result of repeated bone repositionings in the growing rabbit calvaria. Seven immature rabbits were subjected to a three-stage surgical procedure, implying that four calvarial bone segments were originally harvested and repositioned according to a rotational scheme; after 6 weeks only three of the bone segments were harvested and repositioned and, finally, after an additional period of 6 weeks, two segments were repositioned. The results were evaluated by radiographic, histologic (with a special scoring system), and histomorphometric analysis. It was found that one or two cranioplasties did not markedly affect graft incorporation, but three procedures significantly reduced graft revascularization and integration. The findings are discussed with special reference to syndromic craniofacial disorders.     

Healing response to various forms of human demineralized bone matrix in athymic rat cranial defects

PURPOSE: This study compared the ability of a bone autograft and four distinct forms of human demineralized bone (DBM) to elicit bone repair in a critical size cranial defect in athymic rats. MATERIALS AND METHODS: Cranial defects were created in athymic rats and then grafted with either an autograft, rat DBM particles in glycerol (rGel), or one of four forms of human DBM: 1) hGel; 2) Putty (DBM fibers in glycerol); 3) Sheet (sheet of DBM fibers); or 4) Flex (DBM fiber sheet with glycerol). Histology, histomorphometry, and radiographic density of the graft sites were evaluated at 8 weeks. RESULTS: Of the grafted defects, 29% to 58% were found to be filled with new bone. The rGel and human forms of DBM stimulated similar amounts of new bone growth in comparison with the autograft-filled defects. The fiber-based grafts produced the largest amounts of new bone. CONCLUSIONS: Human DBM in gel, putty and sheet forms were found to perform as well as an autograft in a critical size cranial defect in the athymic rat.     

Thermal side effects after use of the pulsed IR laser on meniscus and bone tissue

Stress proteins (sps) 27, 34, 70 and 90 (Mr x 10(3)) were induced in the hypothalamus of caloric restricted (CR) rats by feeding stress. A definite time pattern for sps synthesis was observed when their induction was examined at several time points after the rats were fed, and the level of sps expression was found to vary significantly at different times of the day. The same group of proteins was induced in ad libitum fed rats when they were subjected to food deprivation for 48 h. Stress protein 34 expression in the hypothalamus of old caloric restricted rats was found to be dependent on blood glucose levels, and was substantially reduced when insulin was added to the glucose infusion. The expression of sps 27, 70 and 90, however, was little changed with glucose and/or insulin infusion.     

Osteochondritis dissecans of the medial femoral condyle associated with congenital hypoplasia of the lateral meniscus and anterior cruciate ligament

BACKGROUND/AIM: Blindness in the developed countries affects 3.5 million people. This study was conducted on the causes of blindness in the Republic of Ireland based on the register of the National Council for the Blind of Ireland. The aim was to determine the prevalence of potentially avoidable blindness and to identify its causes. METHOD: Criteria for registration as blind are in Ireland: best corrected visual acuity of 6/60 (0.1) or less in the better eye or a visual field restricted to 20 degrees or less. Data on 5002 adults 16 years an older registered as blind were analysed. The causes of blindness are classified in 17 diagnostic categories. RESULTS: The leading causes of blindness are macular degeneration and glaucoma, each accounting for 16% (812 and 795). Cataract accounted for 11% (561), a third of these had an associated cause of blindness and one tenth had a cognitive deficit. Diabetic retinopathy ranked as the 11th cause of blindness and accounted for 3% (147). More than half of the patients were 65 years and older. CONCLUSION: 25% of blindness was potentially avoidable. The treatable causes were glaucoma and diabetic retinopathy in the working population and glaucoma and cataract over 65 years of age. Glaucoma is the most important, which raises the question of a screening programme. The prevalence of blindness of 3% due to diabetic retinopathy is lower than in most other series.     

Arthroscopic reattachment of the meniscus

Basic fibroblast growth factor (bFGF) has been detected in bone cells and stimulates osteoblast proliferation; however, its role in the regulation of bone metabolism remains speculative. We demonstrated that the human osteocalcin promoter is activated by bFGF when transfected into rat osteoblastic (ROS 17/2.8) cells. This effect is concentration dependent, with a twofold induction at 10 ng/ml detected after 20 h. The bFGF response is independent of both the 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] and retinoic acid activation of the osteocalcin promoter. To identify the promoter sequences through which bFGF exerts its effect, we tested a series of promoter deletion constructs for their response to bFGF. Deletion of the upstream region between -673 and -588 bp results in a significant loss of induction. Gel-shift analysis demonstrates that proteins present in ROS 17/2.8 nuclear extracts bind specifically to these sequences. This region alone was unable to confer the bFGF response on a minimal osteocalcin or an heterologous promoter. However, sequences between -678 and -476 bp, which also includes the vitamin D response element (VDRE), were able to confer bFGF inducibility on both a minimal osteocalcin and a heterologous promoter. These data suggest that induction of the human osteocalcin promoter by bFGF requires the interaction of more than one sequence element.     

Comparative evaluation of bone suture anchor to bone tunnel fixation of tibialis anterior tendon in cadaveric cuboid bone: a biomechanical investigation

A multiphase biomechanical study was performed using human tibialis anterior tendons and cuboid bones, comparing the fixation of the tendon to the bone using bone anchors and bone tunnels. Twenty-six specimens were tested for ultimate load to failure comparing Mitek Superanchor fixation with no. 1 and no. 5 braided polyethelyne suture to bone tunnel fixation. Mitek Superanchor with no. 5 suture failed at 223 N, compared with Mitek Superanchor with no. 1 suture at 134 N and bone tunnel at 143 N (P = 0.033). Mitek with no. 1 suture versus bone tunnel was not significantly different. The Mitek with no. 5 suture failed at the tendon/suture interface (75%), the Mitek with no. 1 suture failed at the suture/anchor interface (56%), and bone tunnel fixation failed most commonly by fracture of the tunnel (76%). This study is the first biomechanical analysis of the pullout strengths of bone tunnels or suture anchors in the cuboid bone. We have shown that the suture anchor has a pullout strength comparable or superior to a conventional bone tunnel in an in vitro situation. We believe it is a viable alternative to fixation of the tibialis anterior tendon to the cuboid when there is insufficient tendon length or failure of the bone tunnel.     

Application of microdialysis for pharmacokinetic study in rabbit anterior chamber

We evaluated a microdialysis technique for analyzing the pharmacokinetics of instilled or orally administered ofloxacin in the anterior chamber of pigmented rabbits. A microdialysis probe was inserted into the anterior chamber and was perfused (2 microliters/min) with Ringer solution using a microinjection pump. Two hours later, 20 microliters of 0.15 and 0.3% ofloxacin was instilled into an eye, or 20 mg/kg of the drug was administered into the stomach through an intubated catheter. Dialysate was then collected every 15 or 20 min for 6 (instillation) or 8 (oral administration) hours. Ofloxacin concentration in dialysates was determined with a HPLC-spectrofluorometry system. Ofloxacin levels in dialysates increased after the instillation in a dose-related manner, reached a maximum at 30 and 45 min, and then decreased gradually with t1/2 of 136 and 114 min after the 0.15% and 0.3% instillation, respectively. After oral administration, ofloxacin levels in dialysates reached a maximum at 120 min and decreased with t1/2 of 175 min. These data suggest the usefulness of microdialysis for pharmacokinetic studies in the anterior chamber, since continuous and stable data can be obtained from each animal.     

Ultrastructural analyses of the attachment (bonding) zone between bone and implanted biomaterials

This report presents transmission electron and high voltage transmission electron microscopic observations of bone and associated remodeling tissues directly interfacing with endosteal dental implants. Undecalcified interfacial tissues were serially sectioned from mandibular samples encasing 60 implants placed into 30 dogs. Two-dimensional ultrastructural analyses and three-dimensional stereology showed that osteogenesis adjacent to dental implants is a dynamic interaction of osseous cells and a collagenous fiber matrix. This study showed that the interfacial bone consists of a mineralized collagen fiber matrix associated with an inorganic (hydroxylapatite) matrix. This study suggested that an unmineralized collagen fiber matrix initially is laid down directly at the implant surface, and that this matrix then is mineralized. Osteoblasts interacted with this matrix, eventually becoming encased within developing lacunae during the remodeling process. This process formed the cellular (osteocyte) aspects of the developed bone. Osteocyte processes extended through canaliculi directly to the implant surface. Apparently, these processes also were entrapped within canaliculi during the mineralization events. At times, these processes paralleled the implant surface. The bone-implant interfacial zone was primarily fibrillar (both mineralized and unmineralized) in morphology, with an electron-dense, ruthenium positive deposition. This electron-dense material was approximately 20 to 50 nanometers in thickness, and only this thin layer separated the remodeled mineralized bone from the implant.     

Leishmania donovani attachment stimulates PKC-mediated oxidative events in bone marrow-derived macrophages

We investigated activation signaling events in bone marrow-derived macrophages after infection with Leishmania donovani, an intracellular parasite of macrophages. Leishmania donovani infection caused a general suppression of activation parameters like O2- and NO production. However, conditions which allow parasite attachment and prevent entry resulted in triggering of O2- and NO production and stimulation of O2 consumption. Optimal NO and O2- production occurred when bone marrow-derived macrophages and Leishmania ratio was 1:100. The activation signal for O2- production was initiated 15 min after parasite attachment, whereas augmentation of NO production started 6 h after attachment Activation of O2- and NO generation by L. donovani attachment was inhibited by staurosporine as well as by prolonged treatment of phorbol myristate acetate suggesting a protein kinase C-dependent mechanism. Translocation studies showed that protein kinase C activity in cell membrane fraction rapidly and transiently increased following parasite attachment. No such protein kinase C translocation event occurred in L. donovani infected bone marrow-derived macrophages. Phorbol myristate acetate was found to stimulate membrane translocation of protein kinase C in parasite attached cells whereas it was impaired in infected cells. However, both attachment and infection induced a similar shift of phorbol receptors from cytosolic to membrane fraction indicating that in infected cells the translocation of protein kinase C protein was not impaired but the activity of the membrane associated enzyme was somehow inhibited. These results suggest that although internalization of intracellular parasites like L. donovani caused inhibition of nitrite and superoxide release, mere attachment on macrophage surface resulted in an activation of protein kinase C-mediated downstream oxidative events.     

Introduction to the special section on attachment and psychopathology: 2. Overview of the field of attachment

An improved system for amplification of hepatitis C virus genome (HCV) was developed based on a multiplex nested polymerase chain reaction format. Two sets of oligonucleotide primers were used simultaneously. One was derived from the conserved sequences in the 5' non-coding region of the viral genome which can bind to the viral genome of all genotypes. The other set of primers was designed from a sequence in the nonstructural-5 region of HCV. HCV genotypes 1 and 3 can be differentiated by the banding patterns of amplified DNA products. All of 39 samples containing the HCV genotype 1 could be amplified with primers in the 5' non-coding region only, whereas 92% of those with genotype 3 could be amplified by both primer sets. In addition, HCV RNA can be detected in 81% of 84 anti-HCV-positive blood donors and in 0% of 34 anti-HCV-negative cases. Of the HCV RNA-positive specimens, 69% showed genotype 1-like patterns while 31% showed genotype 3-like patterns. The detection rate of HCV RNA in this study was much higher than that in our previous report due to the improvement of new primers which can detect all genotypes of the virus. In conclusion, this improved amplification system is a sensitive method for rapid identification of HCV RNA in clinical specimens that can simultaneously differentiate the two most common genotypes of HCV found in Thailand.     

The effects of graft rotation on attachment site separation distances in anterior cruciate ligament reconstruction

We created a model to see if twisting the graft in an anterior cruciate ligament reconstruction affected the distance separating the femoral and tibial attachments of the perimeter fibers of a patellar tendon graft. Graft bone plugs were simulated by two 12.5-mm diameter Delrin cylinders. Holes, 1 mm in diameter, were placed at the four corners of a centralized rectangle measuring 5 by 10 mm. Graft ligament fibers were represented by color-coded sutures passed through the holes in the modeled bone plugs. This graft model was fixed in tunnels reamed under arthroscopic guidance at the anterior cruciate ligament attachment sites of the femur and tibia in six fresh-frozen knee specimens. Spring gauges were used to measure indirectly the changes in distance of separation during knee flexion between the femoral and tibial attachments relative to a zero defined at 90 degrees of knee flexion. The tibial cylinder was rotated at 45 degrees increments from 90 degrees external to 180 degrees internal rotation relative to the femoral cylinder and measurements were repeated after each incremental rotation. External rotation resulted in a statistically significant higher mean separation distance (4.5 mm) for peripheral graft attachments than internal rotation (2.8 mm) (P = 0.05).     

Adult attachment and the transition to parenthood.

This study examined how a major life stressor—the transition to parenthood—affects marital satisfaction and functioning among persons with different attachment orientations. As hypothesized, the interaction between women's degree of attachment ambivalence and their perceptions of spousal support (assessed 6 weeks prior to childbirth) predicted systematic changes in men's and women's marital satisfaction and related factors over time (6 months postpartum). Specifically, if highly ambivalent (preoccupied) women entered parenthood perceiving lower levels of support from their husbands, they experienced declines in marital satisfaction. Women's ambivalence also predicted their own as well as their husbands' marital satisfaction and functioning concurrently. The degree of attachment avoidance did not significantly predict marital changes, although women's avoidance did correlate with some of the concurrent marital measures. These findings are discussed in terms of attachment theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)