Prosthetic hip failure: retrospective radiograph image analysis of the acetabular cup

A method has been developed for quantifying movement and wear of the acetabular component (cup) of total hip replacements (THR) from routine postoperative and review radiographs. The method uses both interactive and automatic computer image analysis techniques. Dimensions of the prosthesis are used to scale the measurements and so overcom variation in radiographic alignment. The application of the method is illustrated by retrospective investigations of cup migration and wear using review radiographs taken over a follow-up of at least 12 years.     

Radiological evaluation of polyethyelene wear of cementless total hip endoprosthesis]

During the last years increasingly cementless hip endoprostheses have been implanted. Radiological wear measurement of cemented hip endoprostheses for the material couples polyethylene cup-ceramic- or metal head has been established in the literature. However, for cups encased by metal (screwing or pressfit cups), this method of measurement is not applicable. Therefore, a method has been developed to measure wear on radiographs on cementless spherical implants. The data were compared to those, obtained from conventional wear measurements on cemented hip cups. The results indicate that both techniques generate comparable results, thus validating the new technique as being suited for cementless cup implants.     

ROC analysis of observer-response subjective rating data--application to periodontal radiograph assessment

Many physical anthropological studies require that an observer or device discriminate between states that can be easily confused. Receiver operating characteristic (ROC) analysis currently offers the best method for determining the accuracy of such choices, particularly for small sample sizes. Although ROC analysis is widely accepted in psychophysical and biomedical testing, its use in anthropological studies has not been reported. ROC analysis is used here to determine the usefulness of enhanced dental radiographs to assess vertical alveolar bone defects for quantitative studies of human variation with regard to periodontal disease. The presence or absence of vertical-bony defects (truth) for 75 human skulls was established by the consensus of two trained observers. Dental bitewing-radiographs were taken of the alveolar processes, the radiographs digitized, and the brightness and contrast of the digital images enhanced. The two observers who established truth then rated 1) plain bitewing radiographs, 2) unenhanced digital images of bitewings, and 3) enhanced digital images of bitewings for vertical bony defects. The rating scale varied from 1 (vertical defect definitely or almost definitely present) to 5 (definitely or almost definitely absent). ROC analysis was used to compared the diagnostic value of the 3 imaging modalities. All modalities had nearly identical diagnostic performance, measured as Az values (areas beneath ROC curves) that were less than 0.80, which indicates only moderate usefulness. It is concluded that enhancement does not increase success in vertical-bony-defect diagnosis from digital dental radiographs processed in this manner. Moreover, it is suggested that conventional bitewing radiographs may be unsuitable for accurate quantification of such defects.     

Bending and fracture of the femoral component in cemented total hip replacement

A computer method was used to make 41 measurements on the geometry of insertion of the femoral component in 200 Charnley total hip replacements. Surgery had been performed at least 12 years before, giving results which were classified as: success (90); fracture (56); or loose (54), according to rigid selection criteria. Fracture was associated with heavier patients in which there was poor proximal fixation of the femoral component but adequate distal fixation. Stems with a medial disposition proximally were more common in the fracture group than in the successful or loose groups. Sequential measurements of bending and subsequent fracture were made on the follow-up radiographs of 24 of the 200 cases (6 fracture and 18 successful). These measurements allowed bending to be detected at an earlier stage than by simple inspection of the radiographs.     

Gonad protection in young orthopaedic patients.

OBJECTIVE--To determine whether gonad shields are correctly positioned on the pelvic radiographs of children with slipped capital femoral epiphysis. DESIGN--Retrospective study of radiographs taken of children treated by in situ pinning of slipped capital femoral epiphysis between 1 January 1983 and 31 December 1988. SETTING--Three teaching hospitals in north west England. PATIENTS--32 patients with complete set of radiographs. RESULTS--An average of 10.8 anteroposterior pelvic radiographs plus 8.9 lateral hip radiographs had been performed per patient. Gonad shields had been completely omitted in 137 (40%) anteroposterior pelvic radiographs performed on the 32 patients at the time of completion of the study. In 100 (29%) the gonad shields were adequately protecting the gonads, but in 109 (31%) the gonad shields were not protecting the gonads due to incorrect positioning of the shield. The incorrect positioning of the gonad shields was more commonly found in girls than boys (64 vs 45; p less than 0.012), presumably because of the difficulty in determining gonadal position in relation to surface landmarks. Absence of gonad shields was also more commonly seen in girls (82 v 55; p less than 0.005), but this is not easily explained. CONCLUSIONS--Gonad shields are not protecting the gonads in a large percentage of anteroposterior pelvic radiographs (71%) because they have been omitted or inadequately placed. This avoidable excess radiation exposure to the gonads, combined with the inability to shield the gonads in lateral hip radiographs and the large number of radiographs performed, results in the gonads receiving a higher dose of radiation than may otherwise be the case, and may increase the potential for disease in the future offspring of these patients.     

Evaluation of Euler's angles with a least squares method for the study of lumbar spine motion

To analyse intervertebral movements, methods with a high level of accuracy are required. Stereoradiographic methods have been used for a number of years to describe intervertebral movements, but their major problem is to identify the same anatomical landmarks, not only on the pair of radiographs used for three-dimensional reconstruction, but also on all the pairs used to analyse the displacements. To minimize the errors due to the incorrect identification of anatomical landmarks, a least squares method to resolve the parameters of Euler's angles was validated by means of measurements made on a spine obtained from a cadaver. The accuracy of this method varied between 0.69° and 0.71° in rotation and between 0.28 mm and 0.77 mm in translation. In addition, this method significantly corrected the position of the anatomical landmarks. Euler's angles, used with a least squares estimate, can provide accurate and precise results.     

Double-blind trial of oral 1,25-dihydroxy vitamin D3 versus placebo in asymptomatic hyperparathyroidism in patients receiving maintenance haemodialysis.

Fifty-seven patients who had been receiving maintenance haemodialysis for a mean of 4.6 years were given 0.25-0.5 microgram oral 1,25-dihydroxy (1,25-(OH)2) vitamin D3 or a placebo in a double-blind manner for one to two years. In patients with normal radiographs (mean plasma parathyroid hormone concentration 205 microliterEq/ml) 1,25-(OH)2 vitamin D3 prevented the development of the radiological appearances of hyperparathyroidism. In patients with abnormal radiographs (mean plasma parathyroid concentration 709 microliterEq/ml) 1,25-(OH)2 vitamin D3 arrested or reversed the radiological changes of hyperparathyroidism. Nevertheless, the response was slow and the concentration of the hormone remained considerably raised (mean 445 microliterEq/ml). It is concluded from these results that giving 1,25-(OH)2 vitamin D3 to patients receiving maintenance haemodialysis who have normal hand radiographs or minimal erosions is beneficial. In patients with more advanced hyperparathyroidism parathyroidectomy should be considered unless there is a rapid response.     

Comparability in skeletal maturation research

Comparability is a fundamental issue in skeletal maturation research. Since the introduction of the first edition of the Greulich-Pyle Atlas and the Tanner-Whitehouse method, a number of methodologic reports have appeared regarding potential sources of error, reliability and replicability in the assessment of skeletal maturity from hand-wrist radiographs. Some of these reports are mentioned and two recent examples of methodologic studies are cited. Maximum reliability of skeletal assessments can be expected only when there is strict adherence to carefully standardized investigative procedures. Technical as well as human factors must be taken into account to insure minimal variation in findings within and between laboratories over time. Single or serial skeletal radiographs uniformly taken on properly identified subjects constitute a valuable permanent record of biologic maturation. while the film image can be considered as objective evidence of skeletal maturity, a subjective element is introduced in observing and reporting the presence or absence of particular ossification centers, or rating an ossification pattern against a standard. Intra- and interobserver skeletal maturity assessment replicability relates to such factors as motivation, training, assessment method, and quality control procedures. Suggestions are presented to facilitate comparability in skeletal maturation research, including the possibility of preparation and distribution of sets of standardized skeletal radiographs for periodic determination and improvement of assessor reliability.     

Tools for high tibial wedge osteotomy

Surgical instruments are described which have been developed for use in high tibial wedge osteotomy. This operation is a treatment for degenerative arthritis of the knee in which one compartment of the joint is predominantly affected resulting in a deformity. Realignment of the bones alters the load distribution on the joint which can relieve pain. Tools have been designed to facilitate the removal of a wedge of bone cut at a precise angle calculated from load bearing radiographs. The tools are a marker pin guide and a saw guide; their use has resulted in accurate bone realignment confirmed by postoperative radiographs.     

Letter to the editor: Commentary on the Fulani—History,genetics, and linguistics,an adjunct to Hassan et al., 2008

Many recent studies have used long bone cross‐sectional geometric properties in various comparative analyses. Methods have been described for reconstructing diaphyseal cross sections from external molds and biplanar radiographs that produce accurate results (within 5% of true values on average). The manual image processing required, however, is both time and labor intensive. A new freely available program developed here for the computational freeware, R, automates much of the process. This study compares cross‐sectional properties calculated using the new R program to those from peripheral quantitative CT (pQCT) and the original manual method. We find that the R program works aswell as the original manual image processing for most cross sections eliminates the chance for entry errors at several steps and greatly speeds up data collection. Am J Phys Anthropol 142:665–669, 2010. © 2010 Wiley‐Liss, Inc.     

Migration of radio-opaque markers injected into tendon grafts: a study using roentgen stereophotogrammetric analysis (RSA)

An increase in anterior laxity following reconstruction of the anterior cruciate ligament (ACL) can result from lengthening of the graft construct either at the sites of fixation and/or between the sites of fixation (i.e., graft substance). Roentgen stereophotogrammetric analysis (RSA), which requires that radio-opaque markers be attached to the graft, has been shown to be a useful technique in determining lengthening in these regions. Previous methods have been used for attaching radio-opaque markers to the graft, but they all have limitations particularly for single-loop grafts. Therefore, the objective of this study was to evaluate injecting markers directly into the substance of a tendon as a viable method for measuring lengthening of single-loop graft constructs by determining the maximum amount of migration after cyclic loading. Tantalum spheres of 0.8 mm diameter were used as tendon markers. Ten single-loop tendon grafts were passed through tibial tunnels drilled in calf tibias and fixed with a tibial fixation device. Two tendon markers were inserted in one tendon bundle of each graft and the grafts were cyclically loaded for 225,000 cycles from 20 N to 170 N. At specified intervals, simultaneous radiographs were obtained of the tendon markers. Marker migration was computed as the change in distance between the two tendon markers parallel to the axis of the tibial tunnel. Marker migration had a root mean square (RMS) value of less than 0.1 mm. Because the RMS value indicates the error introduced into measurements of lengthening and because this error is negligible, the method described for attaching markers to single-loop ACL grafts has the potential to be useful for determining lengthening of single-loop ACL graft constructs in in vivo studies in humans.     

Radiographic estimation of long bone cross-sectional geometric properties

Because of their biomechanical significance, cross-sectional geometric properties of long bone diaphyses (areas, second moments of area) have been increasingly used in a number of form/function studies, e.g., to reconstruct body mass or locomotor mode in fossil primates or to elucidate allometric scaling relationships among extant taxa. In the present study, we test whether these biomechanical section properties can be adequately estimated using biplanar radiographs, as compared to calculations of the same properties from computer digitization of cross-sectional images. We are particularly interested in smaller animals, since the limb bone cortices of these animals may not be resolvable using other alternative noninvasive techniques (computed tomography). The test sample includes limb bones of small (25–5,000 g) relatively generalized quadrupedal mammals—mice, six species of squirrels, and Macaca fascicularis. Results indicate that biplanar radiographs are reasonable substitutes for digitized cross-sectional images for deriving areas and second moments of area of midshaft femora and humeri of mammals in this size range. Potential application to a variety of questions relating to mechanical loading patterns in such animals is diverse. © 1993 Wiley-Liss, Inc.     

Reliability of the Radiographic Sagittal and Frontal Tibiotalar Alignment after Ankle Arthrodesis

BackgroundAccurate measurement of the tibiotalar alignment is important in radiographic outcome assessment of ankle arthrodesis (AA). In studies, various radiological methods have been used to measure the tibiotalar alignment leading to facultative misinterpretation of results. However, to our knowledge, no previous study has investigated the reliability of tibiotalar alignment measurement in AA. We aimed to investigate the reliability of four different methods of measurement of the frontal and sagittal tibiotalar alignment after AA, and to further clarify the most reliable method for determining the longitudinal axis of the tibia.MethodsThirty-eight weight bearing anterior to posterior and lateral ankle radiographs of thirty-seven patients who had undergone AA with a two screw fixation technique were selected. Three observers measured the frontal tibiotalar angle (FTTA) and the sagittal tibiotalar angle (STTA) using four different methods. The methods differed by the definition of the longitudinal tibial axis. Method A was defined by a line drawn along the lateral tibial border in anterior to posterior radiographs and along the posterior tibial border in lateral radiographs. Method B was defined by a line connecting two points in the middle of the proximal and the distal tibial shaft. Method C was drawn „freestyle”along the longitudinal axis of the tibia, and method D was defined by a line connecting the center of the tibial articular surface and a point in the middle of the proximal tibial shaft. Intra- and interobserver correlation coefficients (ICC) and repeated measurement ANOVA were calculated to assess measurement reliability and accuracy.ResultsAll four methods showed excellent inter- and intraobserver reliability for the FTTA and the STTA. When the longitudinal tibial axis is defined by connecting two points in the middle of the proximal and the distal tibial shaft, the highest interobserver reliability for the FTTA (ICC: 0.980; CI 95%: 0.966–0.989) and for the STTA (ICC: 0.997; CI 95%: 0.996–0.999) is provided. Intergroup analysis for FTTA measurements revealed a statistically significant difference between the method in which the lateral border of the tibia was used to determine the longitudinal axis of the tibia, and the other methods in which the longitudinal axis was defined by bisecting the tibia.ConclusionsWhen the longitudinal axis of the tibia is defined by connecting two points in the middle of the proximal and the distal tibial shaft for measuring the FTTA and STTA, the most favorable interobserver reliability is provided. Therefore, this method can be recommended for evaluating the frontal and the sagittal alignment on anterior to posterior and lateral radiographs after ankle arthrodesis.     

Multifactorial determination of skeletal age at death: a method and blind tests of its accuracy

Traditional methods of estimating skeletal age at death have relied solely on the pubic symphyseal face or on this indicator combined with others in nonsystematic ways. A multifactorial method is presented that uses a principal components weighting of five indicators (public symphyseal face, auricular surface, radiographs of proximal femur, dental wear, and suture closure). This method has been tested by completely blind assessment of age in two samples from the Todd collection carefully screened for accuracy of stated age at death. Results show a marked superiority of the multifactorial method over any single indicator with respect to both bias and accuracy. This represents the first truly blind test of an age-at-death indicator or system, as the test populations were independent of the system(s) being tested, and the age, sex, and ethnogeographic origin of the individuals being assessed (as well as the compositions of the test samples with respect to these variables) were completely unknown until the tests were completed. Implications for paleodemography are discussed.     

A radiographic study of porotic hyperostosis

Skull lesions known as porotic hyperostosis have been of interest to researchers since the mid-19th century. The etiology of porotic hyperostosis has long been a matter for speculation yet there has never been complete acceptance or substantiation of any one of the many theories proposed. Today the most widely accepted theory suggests that anemias of either acquired or genetic origin are responsible for porotic hyperostosis. The present study tests this hypothesis using criteria which were chosen after the examination of clinical radiographs of patients with various types of anemia. These criteria are: the presence of “hair-on-end” trabeculation, outer table thinning, texture changes, diploic thickening, orbital roof thickening, orbital rim changes, and the underdevelopment of frontal sinuses. A comparison of these criteria from the clinical X-rays with X-rays of skulls with porotic hyperostosis provides a more rigorous, repeatable, and standardized method upon which to base a diagnosis. This approach enables radiography to provide the necessary link between the clinical and anthropological with which to investigate the origin of porotic hyperostosis.     

Correlations between rates of epiphyseal and diaphyseal elongation in the short bones of the hand

Serial annual radiographs of the hand have been used to analyze the rates of elongation of the epiphyses and diaphyses of the metacarpals and phalanges in children at ages from 3 to 13 years. The rates of elongation for many corresponding ephiphyses and diaphyses (i.e., of the same bone) are negatively correlated but to an extent that is not statistically significant for any particular bone. This tendency toward negative correlations is found for most of these bones although the correlation coefficients for most of the metacarpals are positive in each sex. Within rays, the correlation indices between the rates of elongation for corresponding epiphyses and diaphyses (i.e., of the same bone) have larger negative or smaller positive values than for those between either adjacent and non-corresponding or non-adjacent and non-corresponding epiphyses and diaphyses (i.e., not of the same bone but of either adjacent or non-adjacent bones). The communality indices for the ratio between the rates of epiphyseal and diaphyseal elongation in particular bones are more highly correlated in the girls than in the boys and within the rows than within the rays. Some implications of the tendency to negative correlations between the rates of elongation of corresponding epiphyses and diaphyses have been discussed.     

A simple non invasive computerized method for the assessment of bone repair within osteoconductive porous bioceramic grafts

Single energy X-ray imaging, due to its low cost and flexibility, is one of the most used and common technique to assess bone state and bone remodeling over time. Standardized X-ray images are needed to compare sets of radiographs for semi-quantitative analyses of tissue remodeling. However, useful mathematical modeling for the analysis of high level radiographic images are not easily available. In order to propose a useful evaluation tool to a wide clinical scenario, we present an innovative calibration algorithm for a semi-quantitative analysis of non-standardized digitized X-ray images. For calibration on a unique standardization scale, three time invariant regions (ROI) of radiographs were selected and analyzed. The accuracy of the normalization method for X-ray films was successfully validated by using an aluminum step wedge for routine X-ray exposures as tool to standardize serial radiographs (Pearson correlation test: R(2) = 0.96). This method was applied to investigate the progression of the new bone deposition within ceramic scaffolds used as osteoconductive substitute in large bone defects taking advantage of a large animal model. This innovative image-processing algorithm allowed the identification and semi-quantification of the bone matrix deposited within the implant. The osteo-integration at the bone-implant interface was also investigated. A progressively increasing bone tissue deposition within the porous bioceramic implant and a progressive osteo-integration was observed during the 12 months of the trial.     

Biomechanical aspects of the repair of intertrochanteric fractures

A two-dimensional model of a repaired intertrochanteric fracture has been proposed in order to estimate the forces transmitted by a sliding screw implant and at the fracture site. These forces have been estimated from the radiographs of 55 repairs which were previously graded as satisfactory or unsatisfactory. The unsuccessful group was found to have significantly higher fracture angles as well as increased forces and moments transmitted by the implant. The results support the view that increased loading of implant and therefore high stresses in the surrounding cancellous bone contribute to the failure of repairs.     

The Identification of Human Remains

The identification of human remains, especially if they have been mutilated or burnt, or occur in skeletal form, may pose a major problem for the forensic physician. It may involve the co-operation of coroner, police officer, forensic pathologist and forensic laboratory. It is first necessary to demonstrate that the remains are human, and that the tissue in question represents one, or more than one, body. A meticulous postmortem examination by the forensic pathologist will reveal all anatomical peculiarities for study and record. Photographs, radiographs, dental charts, fingerprints and blood type all contribute materially to the solution of the problem.