Locking plate constructs in subtrochanteric fixation: a biomechanical comparison of LCP screws and AO-nuts.

OBJECTIVES: Various studies have reported the use of the 95-degree condylar blade plate in the treatment of a subtrochanteric fracture or non-union. However, the holding power of standard screws in the metaphyseal and diaphyseal area is often diminished due to osteopenia. The alternative in this area is the use of locking plates, Schühlis or AO-nuts. With the latter two, non-locking screws in the blade plate can be converted to a fixed angle fixation. The objective of this study was to compare the stiffness and strength of the AO-nut augmented 95-degree condylar blade plate construct with that of a locking plate construct. In addition, a clinical series of eight patients treated with the AO-nut augmented 95-degree condylar blade plate construct is presented. METHODS: Single screw-plate constructs of a 5.0 mm locking screw/locking compression plate (LCP) and a 4.5 mm non-locking screw/4.5 mm dynamic compression plate (DCP), converted to a fixed-angle screw construct using AO-nuts, were tested by cantilever bending. During loading, force and displacement were recorded, from which the bending stiffness (N/mm) and the yield strength (N) were determined. Secondarily, all patients that underwent surgical treatment for subtrochanteric fracture, malunion or non-union by the senior author using this technique, underwent chart review. RESULTS: The stiffness of the locking screws was about four times higher compared to the AO-nut augmented construct. The yield strength was 2.3 times higher for the locking screw construct. In none of the eight patients treated with the fixed-angle blade plate, failure of the AO-nut augmented construct occurred. CONCLUSIONS: Although the stiffness and strength of the AO-nut augmented construct is less than of the locking screw, excellent clinical outcomes can be achieved utilizing this construct.

Improved diagnostic confidence in evaluating bone non-union using virtual monochromatic dual-energy CT.

PURPOSE: The aim of this study was to determine whether virtual monochromatic dual-energy CT imaging improves the evaluation of suspected non-union of the appendicular skeleton treated with titanium or stainless steel intramedullary nails and plates. METHOD: Forty-one patients with a clinical suspected non-union with hardware in place were included and scanned on a dual-source CT-scanner using 100/Sn150kVp. Images including titanium hardware were extracted at 130 keV. Images including stainless steel hardware were extracted at 150 keV. Monochromatic 70 keV images served as reference. Non-union confirmed during revision surgery was used as gold standard. A musculoskeletal radiologist and orthopedic trauma surgeon evaluated images on image quality, degree and location of consolidation, non-union type and diagnostic confidence. RESULTS: Likert scores with respect to image quality improved from 0.88 to 1.83 (p < 0.001) in high (130 and 150) keV images. High keV images reduced the number of false negative non-unions based on consolidation grade with 5% (p = 0.283). Agreement between observers regarding location of consolidation and non-union type did not improve in 130 and 150 keV images. Diagnostic confidence improved from 1.43 to 2.37 in high keV images compared to 70 keV images (p < 0.001). Overall diagnostic confidence was higher in intramedullary nails than plates (p < 0.05). CONCLUSIONS: Use of virtual monochromatic 130 and 150 keV dual-energy CT compared to 70 keV images improves the evaluation of suspected non-union of the appendicular skeleton treated with titanium or stainless steel intramedullary nails and plates.

Three-dimensional topography of scapular nutrient foramina.

PURPOSE: The aim of this study is to describe the number and location of the nutrient foramina in human scapulae which can minimize blood loss during surgery. METHODS: 30 cadaveric scapulae were macerated to denude the skeletal tissue. The nutrient foramina of 0.51 mm and larger were identified and labeled by adhering glass beads. CT scans of these scapulae were segmented resulting in a surface model of each scapula and the location of the labeled nutrient foramina. All scapulae were scaled to the same size projecting the nutrient foramina onto one representative scapular model. RESULTS: Average number of nutrient foramina per scapula was 5.3 (0-10). The most common location was in the supraspinous fossa (29.7%). On the costal surface of the scapula, most nutrient foramina were found directly inferior to the suprascapular notch. On the posterior surface, the nutrient foramina were identified under the spine of the scapula in a somewhat similar fashion as those on the costal surface. Nutrient foramina were least present in the peri-glenoid area. CONCLUSION: Ninety percent of scapulae have more than one nutrient foramen. They are located in specific areas, on both the posterior and costal surface.

Correction to: Three­dimensional topography of scapular nutrient foramina.

Correction to: Surgical and Radiologic Anatomy.

Interdisciplinary consensus of virtual monochromatic dual-energy CT images: is there discrepancy in preferred photon energy between surgeons and radiologists for the assessment of non-unions?

AIM: To investigate possible differences between surgeons and radiologists in selecting optimal photon energy settings from a set of virtual monochromatic dual-energy computed tomography (CT) images for the assessment of bone union in patients with a suspected non-union of the appendicular skeleton. MATERIALS AND METHODS: Fifty patients suspected of having bone non-union after operative fracture treatment with a variety of fixation implants were included. Patients were scanned on a dual-source CT machine using 150/100-kVp. Monochromatic images were extracted at 70, 90, 110, 130, 150, and 190 keV. Images were reviewed by 159 orthopaedic trauma surgeons and 12 musculoskeletal radiologists in order to select the best and worst energy setting to assess bone union. Furthermore, a confidence score (1-4) was given in selecting the best and worst setting to assess bone union. RESULTS: Monochromatic 190 keV images were selected most frequently as the optimal energy in titanium (34.8%), stainless steel (40%), and combined implants of stainless steel and titanium (40.5%). Confidence scores and average optimal energies were higher and average worst energies were lower for radiologists compared to surgeons in all hardware (p<0.05). Differences in optimal energy were not statistically significant for different alloys or type of fixation implant in both groups. CONCLUSIONS: In both observer groups, 190 keV images were selected most frequently as the optimal energy to assess bone union in patients with a suspected non-union of the appendicular skeleton with hardware in situ. On average, musculoskeletal radiologists selected higher optimal and lower worst energy settings and were more confident in selecting both energy settings than orthopaedic trauma surgeons.

The "coracoid tunnel view": a simulation study for finding the optimal screw trajectory in coracoid base fracture fixation.

PURPOSE: Coracoid fractures represent approximately 3-13% of all scapular fractures. Open reduction and internal fixation can be indicated for a coracoid base fracture. This procedure is challenging due to the nature of visualization of the coracoid with fluoroscopy. The aim of this study was to develop a fluoroscopic imaging protocol, which helps surgeons in finding the optimal insertion point and screw orientation for fixations of coracoid base fractures, and to assess its feasibility in a simulation study. METHODS: A novel imaging protocol was defined for screw fixation of coracoid base fractures under fluoroscopic guidance. The method is based on finding the optimal view for screw insertion perpendicular to the viewing plane. In a fluoroscopy simulation environment, eight orthopaedic surgeons were invited to place a screw down the coracoid stalk through the coracoid base and into the neck of 14 cadaveric scapulae using anatomical landmarks. The surgeons placed screws before and after they received an e-learning of the optimal view. Results of the two sessions were compared and inter-rater reliability was calculated. RESULTS: Screw placement was correct in 33 out of 56 (58.9%) before, and increased to 50 out of 56 (89.3%) after the coracoid tunnel view was explained to the surgeons, which was a significant improvement (p < 0.001). CONCLUSIONS: Our newly developed fluoroscopic view based on simple landmarks is a useful addendum in the orthopaedic surgeon's tool box to fixate fractures of the coracoid base.

A survey of report writing by neuropsychologists, I: general characteristics and content.

A survey addressing professional practices regarding the content and format of reports on clinical neuropsychological assessments was sent to a randomly selected sample of 750 US members of Division 40 of the American Psychological Association. A total of 414 usable replies were received, yielding a response rate of 55%. Although there was widespread agreement between respondents with different clinical practices regarding the need to include in reports various specific variables (e.g., patient age and education, referral agent and question), there was considerable variability with regard to other items. Most notably, frequency of comments about prior financial compensation seeking varied with patient age group, diagnostic category, and reimbursement source, whereas patient age group and (to a lesser extent) psychologist's board certification were associated with different habits regarding specification of the utilized norms. It is concluded that, although there are many similarities among clinical documentations from different sources, the content of neuropsychological reports tends to vary with the specific practice parameters of the individual neuropsychologist.

A survey of report writing by neuropsychologists, II: test data, report format, and document length.

Data are presented regarding current practices in the organization of neuropsychological reports, based on a representative sample of 414 US members of Division 40 of the American Psychological Association. The vast majority of the sample included some numeric test data in their reports, either within the text or as an addendum. The nature of the most predominant age groups and diagnostic categories served by neuropsychologists was of prominent influence on variables such as the frequency of utilization of age- and grade-equivalent scores, the inclusion of specific diagnostic codes, the provision of narrative recommendations, and the practice of deferring report distribution until after review with the patient or family. In addition, greater involvement with forensic evaluations in a medicolegal context through private practice tended to increase length of reports. It is concluded that, although there are many areas of consensus in the field with regard to the organization of neuropsychological reports, the final product needs to be shaped on the basis of consideration of the clinical presentation of the patient as well as the needs and knowledge base of the target audience.

Factor index score patterns in the WAIS-III standardization sample.

Representative profile subtypes, based on factor index scores, were examined in the standardization sample of the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III). Two-stage cluster analysis identified five reliable subtypes. Three clusters were differentiated primarily by level of performance across all factor index scores (ranging from below average, to average, to above average). The other two clusters were characterized by distinct patterns of performance, with relative efficacy on the Processing Speed index being the most prominent distinction (ranging from a relative weakness to a relative strength). The clusters did not differ significantly in age, but ethnicity and income covaried directly with level of WAIS-III performance, whereas gender affected differential patterns of performance. Furthermore, education and memory were associated primarily with level and, to a relatively minor degree, pattern of WAIS-III performance. Implications for clinical practice are discussed.

Subjective symptomatology after traumatic head injury.

BACKGROUND: Controversy persists regarding the reasons for persistent subjective complaints after mild traumatic head injury (THI). STATEMENT OF PURPOSE: To evaluate the influence of injury severity, psychological factors, and financial contingencies on symptomatology after THI. METHODS: Subjective complaints about cognitive, emotional, and somatic symptoms, as assessed by a standardized self-report inventory (Minnesota Multiphasic Personality Inventory-2; MMPI-2) were evaluated in 150 patients with THI. RESULTS: Individuals with mild THI demonstrated paradoxically greater symptomatology on the MMPI-2 than patients with moderate-to-severe THI. Furthermore, specific actuarial criteria for possible symptom magnification (Fake Bad Scale) were met about twice as often in patients with mild THI who were seeking financial compensation for alleged acquired dysfunction than in patients with mild THI without such external contingencies. CONCLUSION: The evaluation of persistent subjective complaints after THI should consider injury severity in concert with psychological and financial/motivational factors. Great caution should be taken in attributing persistent symptomatology after mild THI to cerebral dysfunction.

Using a short form of the WISC-III: sinful or smart?

This article describes an example of making pediatric neuropsychological assessments more time-efficient. Empirical support, including new data, for the utilization of an eight-subtest short form of the Wechsler Intelligence Scale for Children-Third Edition (WISC-III; Wechsler, 1991) is reviewed. It is concluded that this short form of the WISC-III is a valid substitute for the complete version under most clinical circumstances, allowing the practitioner to expand on interview, history or more specific neuropsychological tests without adding financial or time burdens to the evaluation.

Criterion validity of new WAIS-II subtest scores after traumatic brain injury.

The criterion validity of the new subtests from the Wechsler Adult Intelligence Scale-Third Edition (WAIS-III; Wechsler, 1997) was evaluated in a sample of 100 patients with traumatic brain injury (TBI). Letter-Number Sequencing and Symbol Search, but not Matrix Reasoning, yielded statistically significant differences in performance between patients with moderate-severe TBI, patients with mild TBI, and demographically matched controls. Level of education accounted for a statistically significant amount of variance in the performance of patients with TBI, in addition to that explained by injury severity variables. It is concluded that Letter-Number Sequencing and Symbol Search have satisfactory criterion validity, but that they need to be supplemented with other measures in the context of neuropsychological evaluations. Matrix Reasoning, on the other hand, is not sensitive to the sequelae of TBI and more studies are needed to determine how it can be used for neuropsychological assessment purposes.

Clinical utility of the Category Test as a multidimensional instrument.

The construct and criterion validities of the Category Test (CT) were evaluated in 162 participants who had sustained traumatic brain injury and had been screened carefully for confounding factors. Maximum likelihood factor analysis identified 2 latent constructs, consistent with previous research. However, only subtests associated with the Proportional Reasoning factor (Subtests V and VI) demonstrated consistent criterion validity in terms of sensitivity to injury severity. Performance of Subtest III, associated with the Spatial Positioning factor, was in the range of chance for more than a third of the sample, without any relationship to injury variables. It was concluded that the CT has construct validity as a multidimensional instrument but that only the Proportional Reasoning factor has criterion validity in the evaluation of sequelae of traumatic brain injury.

Predictors of parental distress after congenital disabilities.

This study investigated the relationship between child functional independence, family dynamics, psychosocial factors, and level of distress in parents of children with congenital disabilities. The Vineland Adaptive Behavior Scales, the Family Assessment Device (FAD), and the Brief Symptom Inventory (BSI) were administered to 60 parents of children with cerebral palsy, 34 parents of children with spina bifida, and 27 parents of children with limb deficiencies. Stepwise multiple regression analyses indicated that the Roles scale from the FAD and the presence of a significant new psychosocial stressor within the previous 6 months were statistically significant predictors of the level of parental distress as assessed by the BSI. Exploration of the extent to which families have adaptive distributions of responsibilities for dealing with domestic tasks, as well as with unrelated life stressors, may be helpful in identifying those parents of children with congenital disabilities who are at risk for distress.

Assessment of incomplete effort with the California Verbal Learning Test.

The false-positive rates of 2 formulas for the detection of incomplete effort on the California Verbal Learning Test (CVLT; Delis, Kramer, Kaplan, & Ober, 1987) were evaluated in a sample of 134 patients with traumatic head injury (THI) who had been carefully screened to eliminate any individuals who might be expected to have financial incentives for poor performance. One formula incorrectly identified only 7.46% of the sample as providing incomplete effort, confirming its potential usefulness in clinical settings. The other formula fared much worse, misidentifying an unacceptably high 18.66% of the sample. Lower levels of education were found to increase the likelihood of false-positive results with that formula. It is concluded that the CVLT holds promise for the evaluation of incomplete effort after THI but only within the context of a more comprehensive neuropsychological evaluation.

Neurobehavioral recovery after pediatric head trauma: injury, pre-injury, and post-injury issues.

This article reviews the most significant demographic, neurological, and psychosocial factors affecting the occurrence of and recovery from traumatic head injury (THI) in children and adolescents. Review of the available literature suggests that, as with adults, there is no compelling evidence for persistent neurobehavioral deficits after mild THI in children. In contrast, neurobehavioral deficits are common in children who have sustained moderate to severe THI. This article emphasizes that a long-term developmental perspective that considers in concert injury, pre-injury, and post-injury variables is needed for a proper appreciation of possible sequelae of pediatric THI. Specific pitfalls in forensic assessments of these children are reviewed. Empirical findings are presented to support the position that neuropsychological evaluations of children with THI that do not consider pre-injury status are likely to lead to misattribution errors. Clinical implications are illustrated with a case example.

Influence of demographic variables on neuropsychological test performance after traumatic brain injury.

The validity of correcting for demographic variables when considering neuropsychological test scores was evaluated in a sample of 136 patients with traumatic brain injury (TBI) who had been screened carefully for premorbid or comorbid confounding factors. When considered in concert with neurological variables, age and education accounted for a significant proportion of the variance in raw scores on the Category Test and the Trail Making Test in the complete sample. Gender did not affect level of test performance. Correcting neuropsychological test scores for demographic variables did not significantly alter their success in identifying patients with severe TBI, but did lead to greater accuracy when classifying individuals with mild-moderate TBI. This investigation concluded that norms that consider the demographic background of the individual are likely to reflect more accurately the neuropsychological status of patients with TBI than interpretations that are based exclusively on raw data.

Novel learning abilities after traumatic head injury in children.

The cognitive abilities of 69 children with traumatic head injury (THI) were evaluated with the California Verbal Learning Test-Children's Version (CVLT-C; Delis, Kramer, Kaplan, & Ober, 1994), the Children's Category Test (CCT; Boll, 1993), and the Wechsler Intelligence Scale for Children-Third Edition (WISC-III; Wechsler, 1991). Compared to children with mild to moderate injuries, children with severe THI demonstrated statistically significant impairments on the CVLT-C Total T-score as well as the WISC-III Processing Speed index, but findings for the CCT were less robust. Longer length of coma and male gender were associated with relatively poorer performance on the CVLT-C. Children with severe THI demonstrated difficulties with both capacity and speed of information processing, which could not be accounted for by attentional or general verbal knowledge factors. It is concluded that the combination of the CVLT-C and the WISC-III is useful in the evaluation of cognitive sequelae of THI but that findings from the CCT must be considered with some caution in this population.