Long-term radiographic appearance of a bioabsorbable biocomposite tibial tuberosity advancement cage implant.

OBJECTIVE: To report the radiographic appearance of a bioabsorbable biocomposite tibial tuberosity advancement cage at least 1 year after implantation. Design Retrospective case series. METHODS: Medical records (February 2014-March 2015) of dogs receiving a biocomposite tibial tuberosity advancement cage were reviewed. Cases were selected if they had undergone surgery at least 1 year before the selection, no additional surgeries were performed, and no known surgical site infection had occurred. Medical record information assessed included signalment, body weight (kg), affected stifle joint (left or right), date of original surgery and the size of biocomposite cage used (9 or 12 mm). Radiographs were evaluated by two blinded radiologists who calculated percentages of osteolucency present in five zones around the cage and assigned a numerical score based on these calculations. Variables were evaluated statistically for effect on lucency percentage and numerical score. RESULTS: Fifty dogs were included. Zone 5 (caudoproximal area) was found to have the lowest lucency percentage and score and zone 3 (distal area) had the highest lucency percentage and score. Twelve-millimetre cages were significantly associated with a higher lucency numerical score than 9 mm cages. CONCLUSION: A biocomposite tibial tuberosity advancement cage was found to have variable amounts of radiographically apparent osseous integration at least 1 year after implantation.

The effect of screw angulation and insertion torque on the push-out strength of polyaxial locking screws and the single cycle to failure in bending of polyaxial locking plates.

OBJECTIVE: To evaluate the mechanical properties of the Polyaxial Advanced Locking System (PAX) in screw push-out and four-point bending. MATERIALS AND METHODS: Screw push-out: PAX locking screws were applied to first generation PAX plates at three different insertion angles with two different insertion torques. A load was applied parallel to the screw axis, and screw push-out force was measured. Four-point bending: PAX plates were applied to a bone model and a fracture gap was simulated. Bending stiffness, bending strength, and bending structural stiffness were evaluated and compared to published data. RESULTS: Screw push-out forces were significantly higher at 0 and 5 degree insertion angles when compared with an insertion angle of 10 degrees. An insertion torque of 3.5 Nm also produced significantly higher push-out forces compared to 2.5 Nm. Four-point bending: Qualitative comparison of the data gained in this study with previously published data suggests that the PAX system bending stiffness and bending structural stiffness seems to be higher than that of other veterinary orthopaedic implants, but the bending strength was similar. CLINICAL RELEVANCE: The PAX locking system offers the benefit of polyaxial screw insertion while maintaining comparable biomechanical properties to other currently available orthopaedic implants.

In vitro mechanical evaluation and comparison of two crimping devices for securing monofilament nylon and multifilament polyethylene for use in extracapsular stabilization of the canine stifle.

OBJECTIVE: To compare the tensile strength and stiffness of non-absorbable suture loops created with two types of crimping devices. METHODS: Loops of monofilament nylon leader line (MN) of 18 kg, 36 kg, and 45 kg multifilament polyethylene (MP) with a crimp and MP with a crimp and knot were mechanically tested to failure in quasistatic tensile loading after being created with either a wave pattern crimp device or three applications of a single crimp device. Each testing group consisted of five samples. Tensile loading to failure at a rate of 9.5 mm/s was used. Failure was defined as a sudden drop in the recorded force. RESULTS: All suture materials failed by breaking near the crimp tube with both crimp devices, with exception of the MP without knot, which slipped through the crimp tube using both devices. Sutures secured with the wave pattern crimping device were significantly stronger with a higher load yield, maximum load, displacement yield, failure displacement, and maximum displacement than the single crimp device. Loops of MP suture crimped by either device plus the addition of a surgeon's knot resulted in a significantly stronger construct than unknotted crimped MP constructs. Crimped MP combined with knot were significantly stiffer, but not stronger, than crimped 45 kg MN. CLINICAL SIGNIFICANCE: Performing extra- capsular repair for ruptured cranial cruciate ligaments with the wave pattern crimp system may result in lower failure rates due to the construct being significantly stronger than the single crimp system.

Communication and control: parent, child, and health care professional interactions during painful procedures.

Through use of a qualitative ethological approach, observations of 17 children who were undergoing 44 painful procedures during cancer diagnosis or treatment were videotaped and analyzed. The children, aged 4 to 18 years, were part of a larger study testing the effectiveness of nonpharmacologic pain management techniques. Analysis of the videotaped observations revealed that several distinct patterns of conversation between caregivers, parents, and children varied greatly among situations. Both child-centered and nonchild-centered communications were demonstrated. During periods of quiet, nonchild-centered behaviors increased. As a child's distress increased, parents actively changed behaviors to redirect verbal support back to the child and to the pain control interventions. Nurses' encouraging parents to be actively involved and physically close during painful treatments may results in less distress and discomfort for the child. In addition, health care professionals need to be aware of the various patterns of child-parent-caregiver interactions and the need to stay focused on the child during painful procedures to enhance the child's ability to cope.

Does breastfeeding empower women? Insights from a select group of educated, low-income, minority women.

A grounded theory study examined the breastfeeding experiences of a small group of educated, low-income, minority women. In-depth interviews were used to collect data. The five themes that emerged as primary descriptors of the experience were against all odds, personal motivation, support, attachment, and telling the world. These themes help to identify the factors that enhanced successful breastfeeding among this select sample of women, and demonstrate that the perception of successful breastfeeding can have an empowering effect on women.

Development, evaluation and use of a pharmacokinetic model for hexachlorobenzene.

This study discusses the background, biological basis, development characteristics, application and evaluation of six physiologically based multicompartment models that describe the absorption, distribution and elimination of hexachlorobenzene (HCB) in growing rats and growing humans. The models for rats and for humans have similar structures but differ in specific physiological parameters. The goal of the modelling effort was to obtain toxicological information about HCB based on its pharmacokinetics. Comparisons were made between estimated tissue concentrations based on the rat models and observed tissue distributions based on pharmacokinetic animal studies with HCB, using both chronic and single-dose studies. The estimates from the female model agreed reasonably well with experimental results, and estimated a long half-life of approximately 180 days in all tissues; it did not, however, duplicate the biphasic tissue efflux of HCB that has been reported in the literature. The male model estimated a half-life of approximately 55 days in all tissues, shorter than that observed experimentally. The estimated yield of metabolites agreed well with values reported in the literature. A pregnancy and offspring model predicted minimal transfer of HCB to the fetal compartment during gestation and extensive mobilization of HCB to the offspring during lactation. This agrees with results reported in the literature. Correlations were obtained between experimentally observed liver toxicity and estimated yield of metabolites; between experimentally observed effects on the central nervous system and estimated HCB concentrations in the brain; and between experimentally observed offspring mortality and estimated extent of lactational HCB transfer. This paper also discusses the effects on tissue concentrations and half-lives of trapping HCB in the intestines by sequestering a large portion of it there. Various characteristics of the human models are discussed. The female model has a biphasic elimination pattern, the second elimination phase having a half-life of greater than 200 days. The pregnancy and offspring model projects extensive transfer of HCB via the milk to the nursing offspring, which correlates with the greater mortality of nursing infants whose mothers were exposed to HCB in Turkey.