Bite Injuries among Vaccination Staff Participating in a Mass Canine Rabies Vaccination Campaign, Haiti 2016-2017.

Elimination of dog-transmitted human rabies worldwide will require large-scale dog vaccination campaigns. However, this places participating vaccinators at increased risk. Data from the 2016-2017 Haitian mass rabies vaccination campaign was analyzed to determine dog bite incidence among vaccinators. A survey was then developed for completion by all identifiable bitten vaccinators covering demographics; experience and training; bite episode details; attitudes toward dogs and rabies; and medical care. A parallel group of unbitten vaccinators was also surveyed. Dog bite incidence was 0.03% (43/127,000) of all dogs vaccinated. The capture, vaccinate, and release method of vaccination carried a significantly higher risk of dog bite (0.35%, 6/1,739 vaccinations) than other methods (P < 0.001). Twenty-seven bitten vaccinators, and 54 control vaccinators were included in the survey analysis. No differences were found between groups in demographics, experience, or training. However, bitten vaccinators were significantly more likely than the control group to have experienced a dog bite before the study period (P < 0.001). This may be associated with a lesser appreciation of dogs, and/or a poorer ability to interpret dog behavioral signals within this group. Although 98% of the control group indicated they would seek medical care for a dog bite, only 35% of bitten vaccinators sought such care. On a yearly basis, for the Haitian campaign, a full series of postexposure rabies vaccinations for all bite victims would prove more cost-effective than preexposure vaccination of all vaccinators. These findings may prove useful for the planning and safety of future mass dog vaccination campaigns.

IGF1-Stimulated Posttraumatic Hippocampal Remodeling Is Not Dependent on mTOR.

Adult hippocampal neurogenesis is stimulated acutely following traumatic brain injury (TBI). However, many hippocampal neurons born after injury develop abnormally and the number that survive long-term is debated. In experimental TBI, insulin-like growth factor-1 (IGF1) promotes hippocampal neuronal differentiation, improves immature neuron dendritic arbor morphology, increases long-term survival of neurons born after TBI, and improves cognitive function. One potential downstream mediator of the neurogenic effects of IGF1 is mammalian target of rapamycin (mTOR), which regulates proliferation as well as axonal and dendritic growth in the CNS. Excessive mTOR activation is posited to contribute to aberrant plasticity related to posttraumatic epilepsy, spurring preclinical studies of mTOR inhibitors as therapeutics for TBI. The degree to which pro-neurogenic effects of IGF1 depend upon upregulation of mTOR activity is currently unknown. Using immunostaining for phosphorylated ribosomal protein S6, a commonly used surrogate for mTOR activation, we show that controlled cortical impact TBI triggers mTOR activation in the dentate gyrus in a time-, region-, and injury severity-dependent manner. Posttraumatic mTOR activation in the granule cell layer (GCL) and dentate hilus was amplified in mice with conditional overexpression of IGF1. In contrast, delayed astrocytic activation of mTOR signaling within the dentate gyrus molecular layer, closely associated with proliferation, was not affected by IGF1 overexpression. To determine whether mTOR activation is necessary for IGF1-mediated stimulation of posttraumatic hippocampal neurogenesis, wildtype and IGF1 transgenic mice received the mTOR inhibitor rapamycin daily beginning at 3 days after TBI, following pulse labeling with bromodeoxyuridine. Compared to wildtype mice, IGF1 overexpressing mice exhibited increased posttraumatic neurogenesis, with a higher density of posttrauma-born GCL neurons at 10 days after injury. Inhibition of mTOR did not abrogate IGF1-stimulated enhancement of posttraumatic neurogenesis. Rather, rapamycin treatment in IGF1 transgenic mice, but not in WT mice, increased numbers of cells labeled with BrdU at 3 days after injury that survived to 10 days, and enhanced the proportion of posttrauma-born cells that differentiated into neurons. Because beneficial effects of IGF1 on hippocampal neurogenesis were maintained or even enhanced with delayed inhibition of mTOR, combination therapy approaches may hold promise for TBI.

Frame-Based Stereotactic Biopsy of Canine Brain Masses: Technique and Clinical Results in 26 Cases.

This report describes the methodology, diagnostic yield, and adverse events (AE) associated with frame-based stereotactic brain biopsies (FBSB) obtained from 26 dogs with solitary forebrain lesions. Medical records were reviewed from dogs that underwent FBSB using two stereotactic headframes designed for use in small animals and compatible with computed tomographic (CT) and magnetic resonance (MR) imaging. Stereotactic plans were generated from MR and CT images using commercial software, and FBSB performed both with (14/26) and without intraoperative image guidance. Records were reviewed for diagnostic yield, defined as the proportion of biopsies producing a specific neuropathological diagnosis, AE associated with FBSB, and risk factors for the development of AE. Postprocedural AE were evaluated in 19/26 dogs that did not proceed to a therapeutic intervention immediately following biopsy. Biopsy targets included intra-axial telencephalic masses (24/26), one intra-axial diencephalic mass, and one extra-axial parasellar mass. The median target volume was 1.99 cm(3). No differences in patient, lesion, or outcome variables were observed between the two headframe systems used or between FBSB performed with or without intraoperative CT guidance. The diagnostic yield of FBSB was 94.6%. Needle placement error was a significant risk factor associated with procurement of non-diagnostic biopsy specimens. Gliomas were diagnosed in 24/26 dogs, and meningioma and granulomatous meningoencephalitis in 1 dog each. AE directly related to FBSB were observed in a total of 7/26 (27%) of dogs. Biopsy-associated clinical morbidity, manifesting as seizures and transient neurological deterioration, occurred in 3/19 (16%) of dogs. The case fatality rate was 5.2% (1/19 dogs), with death attributable to intracranial hemorrhage. FBSB using the described apparatus was relatively safe and effective at providing neuropathological diagnoses in dogs with focal forebrain lesions.

Fiberoptic microneedle device facilitates volumetric infusate dispersion during convection-enhanced delivery in the brain.

BACKGROUND AND OBJECTIVES: A fiberoptic microneedle device (FMD) was designed and fabricated for the purpose of enhancing the volumetric dispersal of macromolecules delivered to the brain through convection-enhanced delivery (CED) by concurrent delivery of sub-lethal photothermal hyperthermia. This study's objective was to demonstrate enhanced dispersal of fluid tracer molecules through co-delivery of 1,064 nm laser energy in an in vivo rodent model. MATERIALS AND METHODS: FMDs capable of co-delivering fluids and laser energy through a single light-guiding capillary tube were fabricated. FMDs were stereotactically inserted symmetrically into both cerebral hemispheres of 16 anesthetized rats to a depth of 1.5 mm. Laser irradiation (1,064 nm) at 0 (control), 100, and 200 mW was administered concurrently with CED infusions of liposomal rhodamine (LR) or gadolinium-Evans blue-serum albumin conjugated complex (Gd-EBA) at a flow rate of 0.1 µl/min for 1 hour. Line pressures were monitored during the infusions. Rodents were sacrificed immediately following infusion and their brains were harvested, frozen, and serially cryosectioned for histopathologic and volumetric analyses. RESULTS: Analysis by ANOVA methods demonstrated that co-delivery enhanced volumetric dispersal significantly, with measured volumes of 15.8 ± 0.6 mm(3) for 100 mW compared to 10.0 ± 0.4 mm(3) for its fluid only control and 18.0 ± 0.3 mm(3) for 200 mW compared to 10.3 ± 0.7 mm(3) for its fluid only control. Brains treated with 200 mW co-delivery exhibited thermal lesions, while 100 mW co-deliveries were associated with preservation of brain cytoarchitecture. CONCLUSION: Both lethal and sub-lethal photothermal hyperthermia substantially increase the rate of volumetric dispersal in a 1 hour CED infusion. This suggests that the FMD co-delivery method could reduce infusion times and the number of catheter insertions into the brain during CED procedures.

Intracranial hyperthermia through local photothermal heating with a fiberoptic microneedle device.

BACKGROUND AND OBJECTIVES: The fiberoptic microneedle device (FMD) seeks to leverage advantages of both laser-induced thermal therapy (LITT) and convection-enhanced delivery (CED) to increase volumetric dispersal of locally infused chemotherapeutics through sub-lethal photothermal heat generation. This study focused on determination of photothermal damage thresholds with 1,064 nm light delivered through the FMD into in vivo rat models. MATERIALS AND METHODS: FMDs capable of co-delivering laser energy and fluid agents were fabricated through a novel off-center splicing technique involving fusion of a multimode fiberoptic to light-guiding capillary tubing. FMDs were positioned at a depth of 2.5 mm within the cerebrum of male rats with fluoroptic temperature probes placed within 1 mm of the FMD tip. Irradiation (without fluid infusion) was conducted at laser powers of 0 (sham), 100, 200, 500, or 750 mW. Evans blue-serum albumin conjugated complex solution (EBA) and laser energy co-delivery were performed in a second set of preliminary experiments. RESULTS: Maximum, steady-state temperatures of 38.7 ± 1.6 and 42.0 ± 0.9 °C were measured for the 100 and 200 mW experimental groups, respectively. Histological investigation demonstrated needle insertion damage alone for sham and 100 mW irradiations. Photothermal damage was detected at 200 mW, although observable thermal damage was limited to a small penumbra of cerebral cortical microcavitation and necrosis that immediately surrounded the region of FMD insertion. Co-delivery of EBA and laser energy presented increased volumetric dispersal relative to infusion-only controls. CONCLUSION: Fluoroptic temperature sensing and histopathological assessments demonstrated that a laser power of 100 mW results in sub-lethal brain hyperthermia, and the optimum, sub-lethal target energy range is likely 100-200 mW. The preliminary FMD-CED experiments confirmed the feasibility of augmenting fluid dispersal using slight photothermal heat generation, demonstrating the FMD's potential as a way to increase the efficacy of CED in treating MG.

[Free scapular or parascapular flaps for soft tissue damage accompanying talus or calcaneus fractures]. / Freier Paraskapular-/Skapularlappen bei frakturbegleitendem Weichteildefekt an Talus oder Kalkaneus.

BASIS: Fractures of the talus or calcaneus with accompanying soft tissue damage require precisely planned treatment to prevent infection of the wound over time, especially in severely injured patients. MATERIAL AND METHODS: Seven patients with fractures of the talus or calcaneus and accompanying 2nd and 3rd degree open or 3rd degree closed soft tissue injuries were followed up retrospectively. These patients were operated on between January 1999 and January 2006 with free fasciocutaneous scapular or parascapular flaps. The average age was 34 (range 16-54). Follow-up was at 6-36 months. RESULTS: Osteosynthesis was primarily in six cases, post-primarily in one, and in four cases exterior fixation was used additively. Temporary vacuum therapy was performed for a mean of 28 days (6-42). Parascapular, scapular, and Latissimus dorsi flap coverage was performed six, one, and one times, respectively. Six flaps healed without complication. One necrosis of a parascapular flap occurred and made a Latissimus dorsi flap necessary. In one case of donor-site wound dehiscense, a local rotation flap became necessary. There was no joint infection or osteomyelitis. Bony consolidation was achieved within all fractures. CONCLUSION: Traumatic soft tissue damage must be taken into account when primary or secondary internal fixation is performed and should influence the choice of implant. Free fasciocutaneous parascapular or scapular flaps are a powerful tool for preventing infection if local flaps are not sufficient to achieve stable soft tissue coverage.

Autologous osteoblasts enhance osseointegration of porous titanium implants.

The goal of this study was to assess the osseointegration of porous titanium implants by means of coating with autologous osteoblasts. Titanium implants (8 x 5 x 4 mm) having drill channels with diameters of 400, 500, and 600 microm were coated with autologous osteoblasts obtained from spongiosa chips. The implants were inserted into the distal femora of 17 adult Chinchilla Bastard rabbits (group I). Uncoated implants were inserted as controls in the contralateral femur (group II). The animals were sacrificed after 5, 11, and 42 days. Intravital fluorochrome labeling and microradiography were used for the assessment of bone ingrowth into the titanium channels. In both groups, no bone tissue was formed in the channels up to day 5. On day 11, group I exhibited significantly more (p<0.05) bone tissue (19.8+/-14.0% vs. 5.8+/-9.1%) with greater bone-implant contact (13.3+/-15.1% vs. 5.7+/-5.3%, p<0.05) at the channel mouths than group II. Bone tissue was formed mainly between day 15 and 30 in group I, in group II between day 25 and 40. Six weeks after implantation, bone tissue filled on an average 68.8+/-15.1% of the mouths of the drill channels in implants in group I, the filling for group II was 49.8+/-18.1% (p<0.05). The average bone-implant contact at the channel mouths after six weeks was 56.5+/-13.5% in group I, 40.2+/-21.9% in group II (p<0.05). 600-microm channels showed at this time point the best osseous integration (p<0.05). Coating with autologous osteoblasts accelerates and enhances the osseointegration of titanium implants and could be a successful biotechnology for future clinical applications.

[Treatment of bites to the hand and wrist--is the primary antibiotic prophylaxis necessary?]. / Die Therapie von Bissverletzungen der Hand und des Handgelenkes - Ist eine Antibiotika-Prophylaxe in jedem Fall notwendig?1.

Animal bites make up a large proportion of the injuries treated in an emergency department. Due to the type of injury, the variety of wounds and the contamination with aerobic and anaerobic organisms, they deserve special attention. In this study, we reviewed 98 patients (55 male/43 female) with bite wounds to the hand and wrist treated between 1995 and 2000. They were either treated conservatively (n = 65) or surgically (n = 33) depending on the clinical findings. In 18 of 33 cases, the reason for surgical treatment was an infection. A primary antibiotic prophylaxis, usually with cephalosporines, was administered in 47 of 98 cases. Results were analysed retrospectively. An infection developed in 32 patients. In six of these patients, an infection developed despite primary antibiotic prophylaxis. Operative treatment became necessary in four of these six cases. Twenty-six of 32 patients were treated without primary antibiotic prophylaxis. Surgical treatment was required in around half (n = 14) of these patients, while the other 12 patients were treated conservatively with antibiotic therapy.Twenty-one of 26 patients presented with bite wounds that were already infected. Microbiological examination revealed a variety of microbes, usually a mixed infection with Pasteurella multocida was found. All organisms were susceptible to treatment with second or third generation cephalosporines.A total of 15 patients had to be operated due to deeper injuries to the bone, extensive soft-tissue injury, or because of injury to a tendon and the tendon sheath. In most patients, a good to acceptable functional result was achieved. Primary antibiotic prophylaxis does not prevent the development of infection. Nevertheless, because of the inherently high infection risk associated with bite wounds to the hand and wrist, prophylaxis should be carried out. In case of severe damage to the soft tissue or signs of infection, early surgical therapy should be considered.

Time-frequency analysis of temporomandibular joint (TMJ) clicking sounds using radially Gaussian Kernels.

Temporomandibular joint (TMJ) sounds and motion were recorded during two clinically-derived movements--simple jaw opening and jaw protrusion followed by opening--from ten patients. A new time-frequency method--radially Gaussian kernel distribution--was applied to classify the TMJ clicking sounds into six groups, type I to type VI, based on the time-frequency patterns of energy distribution. The number of clicks and percentage of each type were examined. Relations between the two movements were examined by the prevalence of each type. A detailed classification of TMJ clicking sounds is provided by time-frequency patterns and may provide a better understanding of temporomandibular disorders.

[Treatment of Galeazzi's fracture - is the surgical revision of the distal radioulnar joint necessary?]. / Die Therapie der Galeazzifraktur - Ist die Revision des distalen Radioulnargelenkes zwingend notwendig?

PURPOSE: Fractures of the radial shaft associated with disruption of the distal radioulnar joint (DRUJ) are termed as Galeazzi-fractures. In Galeazzi's fracture, the aim of treatment is restoring the congruency of the joint and the stability of the DRUJ, thus preventing a loss of pronation or supination. PATIENTS AND METHOD: In this study, we included 24 patients (m = 22, f = 2) with 25 Galeazzi fractures treated between 1980 and 1998. Surgical treatment and the duration of therapy were analyzed retrospectively. The clinical and radiological results of 15 patients were followed up. Two children were treated conservatively with immobilization in an above-the-elbow plaster. 19 patients were treated surgically by rigid internal fixation with a plate approximately one week after the accident. Four patients were treated initially in a different way. In 13 cases, the distal radioulnar joint was immobilized by pinning with Kirschner wires. In ten patients, the DRUJ showed no instability. Patients with DRUJ pinning received an above the elbow plaster for six weeks, the other patients received a forearm cast for the time of wound healing. RESULTS: Two patients developed a pseudarthrosis following Kirschner-wire or rush-pin osteosynthesis. The consolidation of remaining fractures was regular. In two patients, the DRUJ was not completely stable after temporary fixation. The remaining patients revealed a stable DRUJ. Eight patients showed a limited pro- or supination after temporary Kirschner wire fixation of the DRUJ. The other patients did not reveal a decrease in range of motion. CONCLUSION: A stable and optimal reduction and a rigid internal osteosynthesis are requisites for healing of the radius fracture. Open reduction of the DRUJ is only indicated when soft tissue interposition prevents exact reposition. Surgical revision of the distal radioulnar joint was not necessary in our patients. Patients after Kirschner-wire fixation showed a diminished pro- or supination. To prevent Kirschner-wire failure, postoperative cast immobilization is indicated. Due to the retrospective nature of the study it is not definitely clear if Kirschner wire fixation is superior to immobilization.

Quantitative description of temporomandibular joint sounds: defining clicking, popping, egg shell crackling and footsteps on gravel.

This study presents a quantitative description of temporomandibular joint (TMJ) sounds provided by a rule-based classification system based on sound classification by three dentists, who listened to and classified the sound recordings as no sound, click, coarse crepitus and fine crepitus. The sounds were recorded with microphones in the ear canal from 126 subjects during vertical opening, digitized at 15 000 Hz, and replayed using a computer sound card and speakers. The dentists' classification of a test set resulted in intra- and inter-tester j values ranging from 0.71 to 0.81 and 0.61-0.73, respectively. Pooled j values for the dentists and the dentists plus the rules were 0.67 and 0.58, respectively, which were not significantly different in terms of the sound features on which the rules were based (P = 0.13). Linear discriminant analysis showed the four TMJ sound types were significantly different (P < 0.001). The performance of the rules was equivalent to the dentists and marginally better than the linear discriminant functions (P = 0.08), establishing the validity of the quantitative descriptions they provide. The recording and rebroadcast methodology produced sounds very similar to those observed in the clinic and could be used to train clinicians in classifying TMJ sounds.

Abnormalities of sexual development in male rats with in utero and lactational exposure to the antiandrogenic plasticizer Di(2-ethylhexyl) phthalate.

Several members of the phthalate ester family have antiandrogenic properties, yet little is known about how exposure to these ubiquitous environmental contaminants early in development may affect sexual development. We conducted experiments to determine effects of in utero and lactational exposure to the most prevalent phthalate ester, di(2-ethylhexyl) phthalate (DEHP), on male reproductive system development and sexual behavior. Sprague-Dawley rats were dosed with corn oil or DEHP (0, 375, 750, or 1,500 mg/kg/day, per os) from gestation day 3 through postnatal day (PND) 21. Dose-related effects on male offspring included reduced anogenital distance, areola and nipple retention, undescended testes, and permanently incomplete preputial separation. Testis, epididymis, glans penis, ventral prostate, dorsolateral prostate, anterior prostate, and seminal vesicle weights were reduced at PND 21, 63, and/or 105-112. Additional dose-related effects included a high incidence of anterior prostate agenesis, a lower incidence of partial or complete ventral prostate agenesis, occasional dorsolateral prostate and seminal vesicle agenesis, reduced sperm counts, and testicular, epididymal, and penile malformations. Many DEHP-exposed males were sexually inactive in the presence of receptive control females, but sexual inactivity did not correlate with abnormal male reproductive organs. These results suggest that in utero and lactational DEHP exposure also inhibited sexually dimorphic central nervous system development. No major abnormalities were found in any of eight control litters, but DEHP caused severe male reproductive system toxicity in five of eight litters at 375 mg/kg/day, seven of eight litters at 750 mg/kg/day, and five of five litters at 1,500 mg/kg/day. These results demonstrate that the male reproductive system is far more sensitive to DEHP early in development than when animals are exposed as juveniles or adults. The effects of DEHP on male reproductive organs and sexual behaviors and the lack of significant effects on time to vaginal opening and first estrus in their littermates demonstrate that DEHP (and/or its metabolites) affects development of the male reproductive system primarily by acting as an antiandrogen. The pattern of effects of in utero and lactational DEHP exposure differed from patterns caused by other phthalate esters, and the preponderance of anterior prostate agenesis appears to be unique among all chemicals. These results suggest that DEHP acts partly by mechanisms distinct from those of other antiandrogens.

Precision of ACL tunnel placement using traditional and robotic techniques.

The objective of this study was to examine the precision of ACL tunnel placement using: (1) CASPAR (orto MAQUET GmbH Co. KG)--an active robotic system, and (2) four orthopedic surgeons with various levels of experience (between 100 and 3,500 ACL reconstructions). The robotic system and each surgeon drilled tunnels for ACL reconstruction in 10 plastic knees (total n = 50) that included a reference cube in the medial aspect of the proximal tibia and distal femur. For the robotic system, the placement of each tunnel was planned preoperatively using custom software and CT data for each femur and tibia. The robotic system then drilled the tunnels in the femur and tibia based on the preoperative plan. For the surgeons, tunnel placement was accomplished using their preferred technique, which was based on the one-incision arthroscopic technique. The distribution of intra-articular points on the tibia was contained within a sphere of radius 2.0 mm (robot system), 2.1 mm (Fellow 1), 2.4 mm (Fellow 2), 3.4 mm (Experienced Surgeon 1), or 2.0 mm (Experienced Surgeon 2). On the femur, no significant differences in the distribution of intra-articular points could be demonstrated between the robotic system (2.1 mm), Fellow 1 (4.5 mm), Fellow 2 (4.1 mm), Experienced Surgeon 1 (2.3 mm), and Experienced Surgeon 2 (3.0 mm). The direction of the tunnels drilled in the femur and tibia was different with the robotic and traditional techniques. However, the robotic system had the most consistent tunnel directions, while the surgeons' tunnels were more dispersed. Variation in surgeon precision of tunnel placement for ACL reconstruction is greater on the femur than the tibia, and this can be correlated with experience. Our data also suggest that the robotic system has the same precision as the most experienced surgeons.

The association between research diagnostic criteria for temporomandibular disorder findings and biting force and endurance in patients with temporomandibular disorders.

OBJECTIVE: This study was designed to evaluate the association between examination findings based on Research Diagnostic Criteria for Temporomandibular Disorders and performances on bite force and endurance tasks. METHODS: Subjects were 126 patients with temporomandibular disorder and 34 pain-free controls. A subset of patients with temporomandibular disorder (n = 56) also were evaluated following a brief conservative 4-week treatment intervention. RESULTS: A multivariate analysis of variance indicated that female patients (P <.001) but not males (P =.17) had lower bite forces than age- and gender-matched controls. Dental examination findings were significantly but modestly predictive of bite task performance (R2 = 0.175), with higher joint pain and smaller maximum unassisted jaw opening associated with lower bite force. The brief treatment interventions resulted in both self-reported and clinically determined improvements. Clinical and self-reported improvement significantly predicted pre-post treatment changes in biting force among female subjects (R2 = 0.237). Specifically, reduction in joint palpation pain and self-reported pain (McGill Pain Questionnaire short form) were the primary predictors of increases in bite force. The improvement in biting force was modest (mean = 7 lb), and the force levels of female patients remained lower than those of control subjects. Treatment did not significantly increase endurance time. DISCUSSION: The brief conservative treatments used resulted in improvements in pain and jaw opening, and 81.8% of patients reported moderate to major improvement. The modest association of the bite task with Research Diagnostic Criteria for Temporomandibular Disorders examination findings and treatment improvement in this heterogeneous sample suggests that the bite and endurance tasks have limited diagnostic utility and sensitivity to treatment effects.

Are all older adults with persistent pain created equal? Preliminary evidence for a multiaxial taxonomy.

BACKGROUND: Persistent pain is grossly undertreated in older adult sufferers, despite its high prevalence in this age group. Because of its multidimensional impacts, including depression, sleep disruption and physical disability, patients with persistent pain often benefit from interdisciplinary pain clinic treatment. This treatment is expensive, however, and may not be required by all patients. The Multiaxial Assessment of Pain (MAP) has demonstrated value in predicting response to treatment in younger adults with persistent pain. OBJECTIVE: To examine the feasibility of a MAP taxonomy for community-dwelling adults age 65 years or older. PARTICIPANTS AND PROCEDURES: One hundred eight subjects with persistent pain (mean age 73.8 years, SD=8.4 years) were interviewed and data collected on demographics, pain intensity, depressive symptoms, sleep disruption, pain interference with performance of basic and instrumental activities of daily living, frequency of engagement in advanced activities of daily living, cognitive function and comorbidity. A subset of these subjects underwent physical capacities testing, including maximal isometric lift strength, dynamic lifting endurance, timed chair rise and balance. RESULTS: Analyses derived three primary clusters of patients. Cluster 1 (24%) reported less intense pain, less depression and sleep disruption, and higher activity levels. Cluster 3 (30%) suffered from more pain and were more functionally disabled. Cluster 2 (46%) had characteristics of cluster 1 and cluster 3, but with some characteristics that were clearly unique. CONCLUSIONS: While these results are preliminary and require further validation, they indicate that older adults are heterogeneous in their response to persistent pain. Future studies should be performed to examine whether the MAP taxonomy is applicable to older adults regardless of medical diagnosis. Ultimately, this information may have meaning with regard to both treatment prescribing, and the design and interpretation of intervention studies.

The forces in the anterior cruciate ligament and knee kinematics during a simulated pivot shift test: A human cadaveric study using robotic technology.

PURPOSE: Although it is well known that the anterior cruciate ligament (ACL) is a primary restraint of the knee under anterior tibial load, the role of the ACL in resisting internal tibial torque and the pivot shift test is controversial. The objective of this study was to determine the effect of these 2 external loading conditions on the kinematics of the intact and ACL-deficient knee and the in situ force in the ACL. TYPE OF STUDY: This study was a biomechanical study that used cadaveric knees with the intact knee of the specimen serving as a control. MATERIALS AND METHODS: Twelve human cadaveric knees were tested using a robotic/universal force-moment sensor testing system. This system applied (1) a 10-Newton meter (Nm) internal tibial torque and (2) a combined 10-Nm valgus and 10-Nm internal tibial torque (simulated pivot shift test) to the intact and the ACL-deficient knee. RESULTS: In the ACL-deficient knee, the isolated internal tibial torque significantly increased coupled anterior tibial translation over that of the intact knee by 94%, 48%, and 19% at full extension, 15 degrees, and 30 degrees of flexion, respectively (P <.05). In the case of the simulated pivot shift test, there were similar increases in anterior tibial translation, i.e., 103%, 61%, and 32%, respectively (P <.05). Furthermore, the anterior tibial translation under the simulated pivot shift test was significantly greater than under an isolated internal tibial torque (P <.05). Under the simulated pivot shift test, the in situ forces in the ACL were 83 +/- 16 N at full extension and 93 +/- 23 N at 15 degrees of knee flexion. These forces were also significantly higher when compared with those for an isolated internal tibial torque (P <.05). CONCLUSION: Our data indicate that the ACL plays an important role in restraining coupled anterior tibial translation in response to the simulated pivot shift test as well as under an isolated internal tibial torque, especially when the knee is near extension. These findings are also consistent with the clinical observation of anterior tibial subluxation during the pivot shift test with the knee near extension.

The effect of the point of application of anterior tibial loads on human knee kinematics.

Coupled axial tibial rotation in response to an anterior tibial load has been used as a common diagnostic measurement and as a means to load the ligamentous structures during laboratory tests. However, the exact location of the point of application of these loads as well as the corresponding sensitivity of the coupled tibial rotation to this point can have an effect on the function of the soft tissues at the joint. Therefore, the purpose of this study was to determine the effects of four different points of application of the anterior tibial load on the anterior tibial translation and coupled axial tibial rotation. The four points include: (1) geometric point - midway between the collateral ligament insertion sites on the tibia, (2) clinical point - a position that attempts to simulate clinical diagnostic tests, (3) medial point - a position medial to the geometric point and (4) lateral point - a position lateral to the clinical point. A robotic/universal force-moment sensor testing system was used to apply the anterior tibial load at the four points of application and to record the resulting joint motion. Anterior tibial translation in response to an anterior tibial load of 100N was found not to vary between the four points of application of the anterior tibial load at all flexion angles examined. However, internal tibial rotation was found for the lateral point (13+/-10 degrees at 30 degrees of knee flexion) in all specimens and clinical point (8+/-10 degrees at 30 degrees of knee flexion) while external rotation resulted when the load was applied at the medial point (-8+/-7 degrees at 30 degrees of knee flexion). Both internal and external tibial rotations occurred throughout the range of flexion when the tibial load was applied at the geometric point. The results suggest that the clinical point should be used as the point of application of the anterior tibial load whenever clinical examinations are simulated and multi-degree-of-freedom joint and soft tissue function are examined.

Significance of changes in the reference position for measurements of tibial translation and diagnosis of cruciate ligament deficiency.

Measurements of tibial translation in response to an external load are used in clinical and laboratory settings to diagnose and characterize knee-ligament injuries. Before these measurements can be quantified, a reference position of the knee must be established (defined as the position of the knee with no external forces or moments applied). The objective of this study was to determine the effects of cruciate ligament deficiency on this reference position and on subsequent measurements of tibial translation and, in so doing, to establish a standard of kinematic measurement for future biomechanical studies. Thirty-six human cadaveric knees were studied with a robotic/universal force-moment sensor testing system. The reference positions of the intact and posterior cruciate ligament-deficient knees of 18 specimens were determined at full extension and at 30, 60, 90, and 120 degrees of flexion, and the remaining five-degree-of-freedom knee motion was unrestricted. Subsequently, under a 134-N anterior-posterior load, the resulting knee kinematics were measured with respect to the reference positions of the intact and posterior cruciate ligament-deficient knees. With posterior cruciate ligament deficiency, the reference position of the knee moved significantly in the posterior direction, reaching a maximal shift of 9.3 +/- 3.8 mm at 90 degrees of flexion. For the posterior cruciate ligament-deficient knee, posterior tibial translation ranged from 13.0 +/- 3.4 to 17.7 +/- 3.6 mm at 30 and 90 degrees, respectively, when measured with respect to the reference positions of the intact knee. When measured with respect to the reference positions of the posterior cruciate ligament-deficient knee, these values were significantly lower, ranging from 11.7 +/- 4.3 mm at 30 degrees of knee flexion to 8.4 +/- 4.8 mm at 90 degrees. A similar protocol was performed to study the effects of anterior cruciate ligament deficiency on 18 additional knees. With anterior cruciate ligament deficiency, only a very small anterior shift in the reference position was observed. Overall, this shift did not significantly affect measurements of tibial translation in the anterior cruciate ligament-deficient knee. Thus, when the tibial translation in the posterior cruciate ligament-injured knee is measured when the reference position of the intact knee is not available, errors can occur and the measurement may not completely reflect the significance of posterior cruciate ligament deficiency. However, there should be less corresponding error when measuring the tibial translation of the anterior cruciate ligament-injured knee because the shift in reference position with anterior cruciate ligament deficiency is too small to be significant. We therefore recommend that in the clinical setting, where the reference position of the knee changes with injury, comparison of total anterior-posterior translation with that of the uninjured knee can be a more reproducible and accurate measurement for assessing cruciate-ligament injury, especially in posterior cruciate ligament-injured knees. Similarly, in biomechanical testing where tibial translations are often reported for the ligament-deficient and reconstructed knees, a fixed reference position should be chosen when measuring knee kinematics. If such a standard is set, measurements of knee kinematics will more accurately reflect the altered condition of the knee and allow valid comparisons between studies.

Effects of body mechanics training on performance of repetitive lifting.

OBJECTIVE: To measure the efficacy of body mechanics instruction (BMI) in patients with low back pain. METHOD: The effect of BMI was measured in four participants with back injuries using a standardized lifting protocol. Static strength, weight lifted, number of lifts completed, and motion analysis data to describe the body mechanics were measured before and after work hardening to evaluate treatment effects. The participants' performances were compared with 52 controls from an earlier study. RESULTS: Starting postures, characterized by degrees of hip and knee flexion, varied by participant but favored a squat lift in three participants when compared with the controls. Dynamic motion synchrony of the hip and knee joints was similar to controls in three of the four participants. Posttest data revealed significant changes in static strength, dynamic endurance, and lifting speed. CONCLUSION: Intensive instruction in body mechanics provided during the work-hardening treatment produced major changes in lifting styles, in terms of both starting postures and dynamic aspects of repetitive lifting. The computerized measurement procedures used in this study permitted more careful and detailed analyses of body mechanics, particularly dynamic aspects, than is possible with observational methods. This study demonstrated some of the inherent intricacies in isodynamic lifting and suggests additional areas of performance that may be important to address in BMI.

In-situ force in the medial and lateral structures of intact and ACL-deficient knees.

The anterior cruciate ligament (ACL) is the major contributor to limit excessive anterior tibial translation (ATT) when the knee is subjected to an anterior tibial load. However, the importance of the medial and lateral structures of the knee can also play a significant role in resisting anterior tibial loads, especially in the event of an ACL injury. Therefore, the objective of this study was to determine quantitatively the increase in the in-situ forces in the medial collateral ligament (MCL) and posterolateral structures (PLS) of the knee associated with ACL deficiency. Eight fresh-frozen cadaveric human knees were subjected to a 134-N anterior tibial load at full extension and at 15 degrees, 30 degrees, 60 degrees, and 90 degrees of knee flexion. The resulting 5 degrees of freedom kinematics were measured for the intact and the ACL-deficient knees. A robotic/universal force-moment sensor testing system was used for this purpose, as well as to determine the in-situ force in the MCL and PLS in the intact and ACL-deficient knees. For the intact knee, the in-situ forces in both the MCL and PLS were less than 20 N for all five flexion angles tested. But in the ACL-deficient knee, the in-situ forces in the MCL and PLS, respectively, were approximately two and five times as large as those in the intact knee (P < 0.05). The results of this study demonstrate that, although both the MCL and PLS play only a minor role in resisting anterior tibial loads in the intact knee, they become significant after ACL injury.