Ulnar Length Research Articles

A comparison of bone quality at the distal radius between Asian and white adolescents and young adults: An HR-pQCT study

Paradoxically, Asians have lower areal bone mineral density (aBMD), but their rates of hip and wrist fractures are lower than whites. Therefore, we used high-resolution pQCT (HR-pQCT) to determine whether differences in bone macrostructure and microstructure, BMD, and bone strength at the distal radius were apparent in Asian (n = 91, 53 males, 38 females, [mean ± SD] 17.3 ± 1.5 years) and white (n = 89, 46 males, 43 females, 18.1 ± 1.8 years) adolescents and young adults. HR-pQCT outcomes included total BMD (Tt.BMD), trabecular bone volume fraction (BV/TV), and trabecular number (Tb.N), thickness (Tb.Th), and separation (Tb.Sp). We used an automated segmentation algorithm to determine total bone area (Tt.Ar), and cortical BMD (Ct.BMD), porosity (Ct.Po), and thickness (Ct.Th), and we applied finite element (FE) analysis to HR-pQCT scans to estimate bone strength. We fit sex-specific multivariable regression models to compare bone outcomes between Asians and whites, adjusting for age, age at menarche (girls), lean mass, ulnar length, dietary calcium intake, and physical activity. In males, after adjusting for covariates, Asians had 11% greater Tt.BMD, 8% greater Ct.BMD, and 25% lower Ct.Po than whites (p < 0.05). Also, Asians had 9% smaller Tt.Ar and 27% greater Ct.Th (p < 0.01). In females, Asians had smaller Tt.Ar than whites (16%, p < 0.001), but this difference was not significant after adjusting for covariates. Asian females had 5% greater Ct.BMD, 12% greater Ct.Th, and 11% lower Tb.Sp than whites after adjusting for covariates (p < 0.05). Estimated bone strength did not differ between Asian and white males or females. Our study supports the notion of compensatory elements of bone structure that sustain bone strength; smaller bones as observed between those of Asian origin compared with white origin have, on average, more dense, less porous, and thicker cortices. Longitudinal studies are needed to determine whether ethnic differences in bone structure exist in childhood, persist into old age, and whether they influence fracture risk.

Hand function in children with radial longitudinal deficiency

BackgroundIn children with hypoplasia or aplasia of the radius (radial longitudinal deficiency) manual activity limitations may be caused by several factors; a short and bowed forearm, radial deviation of the wrist, a non-functional or absent thumb, limited range of motion in the fingers and impaired grip strength. The present study investigates the relation between these variables and activity and participation in children with radial dysplasia.MethodsTwenty children, age 4–17 years, with radial longitudinal dysplasia Bayne type II-IV were examined with focus on the International Classification of Functioning and Health, version for Children and Youth (ICF-CY) context. Body function/structure was evaluated by measures of range of motion, grip strength, sensibility and radiographic parameters. Activity was examined by Box and Block Test and Assisting Hand Assessment (AHA). Participation was assessed by Children’s Hand-use Experience Questionnaire (CHEQ). Statistical correlations between assessments of body function/structure and activity as well as participation were examined.ResultsThe mean total active motion of wrist (49.6°) and digits (447°) were less than norms. The mean hand forearm angle was 34° radially. Ulnar length ranged from 40 to 80% of age-related norms. Grip strength (mean 2.7 kg) and Box and Block Test (mean 33.8 blocks/minute) were considerably lower than for age-related norms. The mean score for the AHA was 55.9 and for CHEQ Grasp efficiency 69.3. The AHA had significant relationship with the total range of motion of digits (p = 0.042). Self-experienced time of performance (CHEQ Time) had significant relationship with total active motion of wrist (p = 0.043). Hand forearm angle did not show any significant relationship with Box and Block Test, AHA or CHEQ.ConclusionIn radial longitudinal deficiency total range of motion of digits and wrist may be of more cardinal importance to the child’s activity and participation than the angulation of the wrist.

Estimation of stature from the upper limb measurements of Sudanese adults

The estimation of stature using different parts of the body is crucial for formulating a biological profile during the process of personal identification, especially when mutilated and amputated limbs or body parts are found. Hand anthropometry has been reported in the literature including limited range of populations to be promising for stature prediction, but few studies have attempted to link upper limb anthropometry to stature. No previous research on this topic has been reported for modern Sudanese adults. Therefore, the aim of this study was to assess the relationship between the upper limb dimensions and stature in Sudanese adults and to develop regression formulae to estimate stature from these dimensions. The stature, upper arm length, ulnar length, wrist breadth, hand length, and hand breadth of 200 right-handed subjects, comprising 100 males and 100 females (aged 25–30 years), were measured. Initially, the data were analyzed using basic univariate analysis and independent t-tests; then sex-specific simple and multiple linear regression models were used to estimate stature. The results indicated significant sexual dimorphism for all measurements. There was a positive correlation between upper limb measurements and stature (p<0.01), which was highest for ulnar length. The accuracy of stature prediction ranged from ±3.54 to 5.85cm. The use of multiple regression equations gave better results than simple regression equations. This study provides new forensic standards for stature estimation from the upper limb measurements of Sudanese adults.

“A study to correlate the stature with the length of ulna in living humans in various age groups”

Aim: The purpose of the study was to establish the correlation between length of ulna with height of a person in various age groups and in both sexes. The study also intended to compare the two basic parameters used globally for such correlations, namely multiplication factor (M.F.) and regression equation; and try to comment on the efficacy of one formula over the other. Introduction: Height of an individual has evoked great interest since ancient time. The subject as a whole has been dealt with in different ways to predict the human stature. In ancient times, physicians & surgeons like Charak & Sushruta1 were well acquainted with the relation of different parts of body with height. According to Charak, the height of an average man should be 84 -anguls, thigh-21 anguls, forearm -15 anguls & arm-16 anguls. Dwarfism and gigantism, both resulting from hormonal dysfunction, are examples of variations in normal body height. Method & Material: In the present study 504 individuals were studied. Study ranged across the age groups from 8 years to 22 years. Equal participation of males and females was ensured. Thus, 252 males (50%) and 252 females (50%) were included in the study. Observation: On an average the M.F. for male is between 6.05 – 6.76 for right ulna and 6.08-6.79 for left ulna. Discussion: It was observed that height estimation using M.F. is much simpler, easy and less time consuming; yet enough efficient; as compared to using regression equation. Conclusion: 1) M.F. is more applicable in medico-legal cases where one may be confronted with a single or fragmented bone, and person’s height needs to be ascertained. 2) Regression equation is applicable in sample study of large population.

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Introduction: In pediatric critical care, accurate placement of endotracheal tubes prevent unplanned extubation or unrecognized bronchial intubation. The optimal position of the endotracheal tube is believed to be 2.0 cm above the carina so that movement of the head does not raise the ETT out of the airway nor push it in to an endobronchial position. The gold standard for confirmation has been the chest radiograph. To reduce exposure to radiation, and ensure optimal position immediately after extubation, non-radiographic techniques to determine optimal placement have included formulas based on body size, ETT size, gestational age, and measured markings on the end of the endotracheal tube. Formulas that relate the length of the trachea to variables such as age, weight, or height are inconsistent, and may be less accurate for children with obesity, failure to thrive, or scoliosis which affect height. Ulnar length is preserved in these populations, and is unaffected by body habitus or neuromuscular disease. Hypothesis: Ulnar length can be used to determine the optimal depth of oro-tracheal intubation. Methods: Any orotracheally intubated child admitted to the pediatric or cardiothoracic intensive care unit was eligible. Routinely obtained chest radiographs were used to determine endotracheal tube position and distance from the carina. The patient’s ulnar length, height, and depth of endotracheal tube insertion were obtained. Optimal endotracheal tube position, calculated as 2 cm above the carina was measured based on current tube position. Ideal ETT depth was plotted against the patient’s ulnar length, and linear regression was used to determine a predictive equation. Results: 58 patients were included. Optimal depth of the endotracheal tube plotted against ulnar length resulted in a linear relationship, given by the following formula: depth of ETT insertion in cm = 0.72(ulnar length in cm) + 5.2 (R2 = 0.84). Conclusions: Optimal depth of endotracheal tube insertion can be rapidly estimated using ulnar length. This information can be used to ensure correct endotracheal tube placement, potentially reducing the need for chest radiographs.

Effect of Osteochondroma Location on Forearm Deformity in Patients With Multiple Hereditary Osteochondromatosis

Multiple hereditary osteochondromatosis (MHO) is an autosomal-dominant skeletal dysplasia that may result in forearm deformity. The purpose of this study was 2-fold: to describe the natural history of forearm deformity in patients with MHO, with particular attention to those who develop radial head dislocation, and to determine predictors of deformity. We retrospectively reviewed charts of all patients with MHO evaluated at our institution. Patients with the presence of a radiographically visible osteochondroma in the forearm were divided into 5 groups or types based on location of the osteochondroma(s). Radiographic measurements included radial articular angle, percent ulnar variance, radial bow, radial length, ulnar length, and ulnar bow. The predictive values of each measure were statistically evaluated for each type with relation to radial head dislocation. Of 146 patients with MHO, 102 patients (70%) had forearm involvement. Appropriate anteroposterior and lateral radiographs were available on 48 patients (76 forearms). Average age at initial radiographic evaluation was 12 years (range, 2-18 y). Average follow-up period was 7 years (range 1-19 y). Thirteen forearms demonstrated radial head dislocation, with all but 1 reported in the type 1 limbs (solitary distal ulna osteochondroma). Radial head dislocation was noted in 34% (12/35 forearms) of type 1 limbs. Forearms with isolated osteochondromas of the distal ulna are the ones most likely to develop radial head dislocation. Because the ulna growth is disproportionately less than radial growth, the soft tissues may act as a tether, linking the distal radius and ulna, and lead to radial head dislocation. Changes in radiographic measurements may predict limbs at risk for radial head dislocation.

Clinical and Radiographic Factors Associated With Distal Radioulnar Joint Instability in Distal Radius Fractures

Distal radioulnar joint (DRUJ) instability is an important cause of ulnar-sided wrist pain in distal radius fractures. However, instability is frequently undiagnosed and the clinical and radiographic factors associated with instability are not well understood. We therefore identified clinical and radiographic factors associated with DRUJ instability in distal radius fractures. We retrospectively reviewed all 221 patients who underwent surgical treatment for unstable distal radius fractures from 2007 to 2010. Ten patients (five men and five women) had DRUJ instability by intraoperative manual testing (Group I); these patients had a median age of 52 years. The other 211 patients (81 men and 130 women) (Group II) had a median age of 55 years. Clinical and radiographic data were compared between the groups. The incidence of open wounds at the wrist and the relative ulnar length measured on the prereduction radiograph were greater in Group I. An open wound at the wrist and positive ulnar variance of 6 mm or greater on the prereduction radiograph increased the risk of DRUJ instability (relative risks = 45 and 17, respectively) in distal radius fractures. An open wound at the wrist or positive ulnar variance of 6 mm or greater observed on the prereduction radiograph in patients with distal radius fractures should alert the physician to the possibility of DRUJ instability. Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Height Prediction from Ulnar Length in Females: A Study in Burdwan District of West Bengal (Regression Analysis)

Stature estimation from the skeletal remains bears immense importance in the forensic sciences. Along with the conventionally used long bones, the humerus, femur, tibia, etc.; the ulna also has been used for the said purpose since 1952. Though studies which had highlighted the stature estimation in Bengalee males were carried on earlier, in females, this has still not been uncovered. An attempt was made to formulate a linear regression equation for the estimation of the stature of living adult Bengalee females from the lengths of their ulna. This study was conducted in the Burdwan Medical College Hospital on 300 subjects who were chosen from among the patients and their lady attendants in the Gynaecology OPD. The height was measured from the crown to the heel and the length of the ulna was measured from the tip of the olecranon process to the tip of the styloid process. The documented data was calculated by the standard statistical software. The parameters were tabulated and statistically analyzed. The correlation coefficient (r) was found to be 0.82 (p=0.002) for the left ulna with stature and it was 0.67 (p=0.001) for the right ulna with stature. Supportive regression equations and scatter-plot diagrams could successfully interpret the height from the ulnar length in females. The ulna being almost a percutaneous bone, it can be used for the prediction of the height. The ulna length provides an accurate and reliable means in estimating the height of an individual. The regression formulae which were proposed in this study will be useful for clinicians, anatomists, archeologists, anthropologists and forensic scientists when such evidence provides the investigator the only opportunity to gauge that aspect of an individual's physical description.

Correlation between the lenghts of the long bones of the forearm and the fibula with body height in our population

The task of a forensic examiner during exhumation of skeletal remains is to calculate antemortem height of a person whose skeletal remains were found. Anthropological investigations which provided formulae for calculating ante-mortem body height date back from XIX or from the first half of XX centuries. The most commonly used formulae are those of Trotter-Gleser, which were used to investigate skeletal remains from the World War II. Those investigations were conducted on skeletal remains of various ages and degrees of decay. Our experience with exhumation have shown that the present formulae do not deliver reliable values of antemortem height. The aim of this study was to investigate if there is a correlation of the length of long bones of leg and forearm with body height within our population and to establish the formulae for calculating ante-mortem body height within our population based on the obtained values. The lengths of ulna, radius, fibula and tibia were determined precisely by measuring bones on living individuals using a digital X-ray system. The height of individuals whose bones were measured was determined using an anthropometer. The highest degree of correlation between bone length and body height was found for tibia in males (r = 0.859, p < 0.005) and ulna in females (r = 0.679, p < 0.05). We calculated the regression formulae for determination of ante-mortem body height that differ from the current body height formulae. In our population the length of long bones of the forearm and the leg are characterized by various degree of correlation with body height. The formulae that we set, make less distinction between the measured and the calculated body height as compared with the Trotter-Gleser formulae. We do hope that their implementation will facilitate identification of sceletal remains in our population.

Investigation of Bone Ratios for Prenatal Fetal Assessment in Taiwanese Population

The purpose of this study is to calculate the ratios of fetal limb bone to nasal bone length (NBL) obtained by transabdominal ultrasound between 19 and 28 weeks of gestation. Cross-sectional data were obtained from 1408 women with singleton pregnancies who underwent an advanced prenatal ultrasound examination from August 2006 to September 2008. The single measurement plane of fetal limb bones was on the longest section of each structure with appropriate image magnification. To assess repeatability of the intraobserver, two repeated measurements were obtained in 44 fetuses. The ratio of fetuses with biparietal diameter (BPD)/NBL was compared with those of fetal limb bones/NBL. The mean ratio was found between fetal NBL measurements and BPD (7.240), humerus length (HL) (4.807), radius length (RL) (4.157), ulna length (UL) (4.502), femur length (FL) (5.131), tibia length (TL) (4.528), and fibula length (FiL) (4.507). The reference ranges of fetal long bone length/NBL ratios for the second trimester was established by transabdominal sonography. There were no significant increases in these ratios with gestational age, especially the HL/NBL ratio.

Case Report: A Rare Variety of Type 4 Monteggia Fracture Dislocation in A 28 Years Old Man

A Monteggia fracture is a fracture of the proximal ulna coupled with a radial head dislocation. Numerous classification systems have been developed to characterize these fractures. Bado classification is most commonly used. Bado type 1 Monteggia fractures are most common while type 3 & 4 are rare entities. In our case, after confirming the diagnosis as type 4 Bado Monteggia fracture dislocation, patient was posted for open reduction and internal fixation. The ulnar and radial fractures were rigidly fixed with 3.5 compression plate and ulnar length restored. However, the radial head was still found to be dislocated anteriorly on fluoroscopy. An attempt of closed reduction of the radial head failed. Open reduction of the radial head was performed under image intensifier and fixed with a Kirschner’s wire followed by immobilization in hyperflexion for 2 weeks. The patient followed up at the end of 2 weeks, 4 weeks and 6 weeks following injury and gradual mobilisation of the elbow joint was made. Further follow up at 6 months and 1 year showed complete return of routine function. As soon as the ulnar length is restored by rigid internal fixation, radial head is itself reduced in majority of Monteggia fracture dislocation where only ulnar fracture is involved. However, in cases of both bone forearm fracture with radial head dislocation, even after restoring the length of ulna and radius, operative reduction of radial head is essential.

Avian wing proportions and flight styles: first step towards predicting the flight modes of mesozoic birds.

We investigated the relationship between wing element proportions and flight mode in a dataset of living avian species to provide a framework for making basic estimates of the range of flight styles evolved by Mesozoic birds. Our results show that feather length (f prim) and total arm length (ta) (sum of the humerus, ulna and manus length) ratios differ significantly between four flight style groups defined and widely used for living birds and as a result are predictive for fossils. This was confirmed using multivariate ordination analyses, with four wing elements (humerus, ulna/radius, manus, primary feathers), that discriminate the four broad flight styles within living birds. Among the variables tested, manus length is closely correlated with wing size, yet is the poorest predictor for flight style, suggesting that the shape of the bones in the hand wing is most important in determining flight style. Wing bone thickness (shape) must vary with wing beat strength, with weaker forces requiring less bone. Finally, we show that by incorporating data from Mesozoic birds, multivariate ordination analyses can be used to predict the flight styles of fossils.

The estimation of body height from ulna length in healthy adults from different ethnic groups

Assessments of nutritional status frequently incorporate a measure of height to evaluate a person's relative thinness or fatness. Because height is often difficult to quantify, it may be predicted from alternative anthropometric measurements, including ulna length. Little information is available about the accuracy of these predictions in an ethnically diverse population. The present study aimed to evaluate published equations for predicting height from ulna length in adults from different ethnic groups. Ulna length and standing height were measured in a gender-stratified sample of 60 Asian, 69 Black and 65 White healthy volunteers, aged 21-65 years. Height was predicted from ulna length using the Malnutrition Universal Screening Tool (MUST) equations and compared against the measured values. Linear regression analysis was used to develop equations to estimate height from ulna length and to explore the relationship between height and ulna length in subgroups. The mean (SD) age for Asian, Black and White in men was 31.7 (11.0), 32.0 (10.3) and 38.6 (12.5) years and in women was 26.2 (5.4), 32.6 (8.9) and 35.7 (11.7); the mean (SD) height in men was 170.9 (5.2), 178.1 (7.3) and 176.3 (7.7) cm and in women was 157.7 (4.7), 164.0 (5.9) and 163.7 (6.2) cm. Ulna length and measured height were significantly correlated among all subgroups, except Asian women (r=0.11, P=0.57). The mean (SD) difference between predicted and measured height showed significant overestimates for Asian and Black men [4.0 (4.8) and 6.7 (5.3) cm] and Asian and Black women [6.4 (4.9) and 4.4 (4.9) cm] but not for White men and women. The MUST equations for predicting height from ulna length in healthy adults should be used with some caution among ethnically diverse populations, particularly in Asian women.

Morphology of the Cubital Tunnel: An Anatomical and Biomechanical Study With Implications for Treatment of Ulnar Nerve Compression

The purpose of this study is to provide a thorough understanding of the anatomy of the cubital tunnel and to outline specific anatomical parameters of the cubital tunnel retinaculum (CuTR) that might aid in the management of ulnar nerve problems. The hypotheses of this study are (1) that the nerve elongates with elbow flexion and (2) that the cross-sectional area of the cubital tunnel is inversely proportional to the degree of elbow flexion. Eleven fresh-frozen cadaver arms were dissected at the medial elbow. The CuTR was identified, and its thickness was measured. After excising the CuTR, we measured the elongation of the anterior and posterior aspects of the ulnar nerve, as well as the length of the CuTR origin/insertion, at increasing intervals of elbow flexion (15°, 30°, 45°, 90°, 120°, and 135°). Using 3-dimensional digitization technology, the surface of the cubital tunnel was recorded at 4 positions of elbow flexion (15°, 45°, 90°, and 135°) and analyzed to define the tunnel geometry. The CuTR origin-to-insertion length and the ulnar nerve length both increased significantly with increasing flexion angle. Both lengths at 90°, 120°, and 135° of elbow flexion were greater than at 15° or 30°. The cubital tunnel area was significantly less at 135° compared to either 45° or 90° of flexion. There was a linear relationship between the cubital tunnel area of the different arms with the corresponding nerve cross-sectional area when measured at the level of the epicondyle and when the arm was at 90° of elbow flexion. The CuTR begins to stretch at 60° of flexion and continues to stretch with increasing flexion. Similarly, the ulnar nerve is more taut in flexion. The area within the cubital tunnel decreases beyond 90° of elbow flexion. Understanding the dynamic anatomical relationships of the cubital tunnel might help in the safe treatment of cubital tunnel syndrome when using minimally invasive techniques and instrumentation.

Ulna length to predict height in English and Portuguese patient populations

This study assessed the extent to which ulna length could be used to predict height and body mass index (BMI) in various groups of English and Portuguese hospitalised patients, and tidal volumes in critically ill patients at risk of requiring ventilatory support. Bedside measurements of weight, height and ulna length were made in 507 patients (432 English, 75 Portuguese; 264 men, 243 women) with a mean age of 61.8±18.9 years, height 165.1±9.5 cm and BMI 26.7±5.43 kg/m(2). Ulna length could be measured with ease in all subjects. The intra-observer technical error of measurement in the same subjects was 1%. Within each category of men and women aged <65 years and 65 years and over, there was no significant difference between the English and Portuguese in the intercept or regression coefficients for the ulna-height relationships. A strong relationship was found between predicted and measured height (r=0.963, standard error of the estimate 4.6 cm). The overall mean and s.d. of the difference was 0.3±2.7% of height, with no significant difference between English and Portuguese populations. The discrepancy between measured and predicted BMI corresponded to 0.7±5.5% (s.d.) (all subjects) and for ventilatory volumes predicted from height (critically ill subjects only) 0.7±7.1%. Height can be predicted from ulna length with precision and ease in a wide range of patient groups, and without the need to use different equations in English and Portuguese populations. The predicted measurements are acceptable in most clinical circumstances.

Oblique Ulnar Styloid Osteotomy—A Treatment for Ulnar Styloid Impaction Syndrome

We report a series of 5 patients (mean age, 41 y) presenting with ulnar styloid impingement syndrome (USIS) and treated by an oblique ulnar styloid osteotomy. The purpose of the study was to determine whether the osteotomy is an effective method for treating USIS. The diagnosis of USIS was made based on a history of ulnar-sided wrist pain supported by clinical and radiological findings. Clinical assessment included provocative tests to differentiate USIS from pain associated with ulnocarpal impaction syndrome. The ulnar styloid length was assessed with a posteroanterior X-ray using the methods of Garcia-Elias and Biyani. The ulnar styloid was deemed excessively long if the ulnar styloid process index was greater than 0.21 or if the overall styloid length was greater than 6 mm. Ulnar variance was recorded. All wrists were assessed by computed tomography arthrography and magnetic resonance imaging studies to rule out any associated soft tissue abnormalities, including ligamentous injuries. Preoperative and postoperative pain levels were recorded using a pain scoring system. Patients were followed up for a mean of 46 months. Before surgery, the mean styloid length was 10 mm, and the ulnar styloid process index was 0.32. The reported pain score was significantly reduced following surgery and all patients, except one, returned to premorbid levels of activity. Oblique ulnar styloid osteotomy is an effective means of relieving impaction of the ulnar styloid while preserving the integrity of the intrinsic ulnar styloid ligaments. Therapeutic IV.

Growth of the Ulna After Repeated Bone Lengthening in Radial Longitudinal Deficiency

Shortening of the ulna is one of the characteristic features of the radial longitudinal deficiency, which could be treated with repeated bone lengthening. The purpose of this study is to assess the changes in growth rate of the ulna after repeated bone lengthening in radial longitudinal deficiency. Five children (3 boys, 2 girls) who underwent twice bone lengthening of the ulna were reviewed. All patients had unilateral Bayne type IV radial longitudinal deficiency and had received centralization of the ulna previously. Ulnar length was measured on radiographs. Percent length against the normal side was used to measure differences between individuals. Ulnar growth rate was calculated as change in length over time. Ulnar length was 57.4% of the normal side on average at first visit to our hospitals. Percent length against the normal side became 88.9% immediately after the first lengthening. Then percent length decreased to 70.1% just before the second lengthening and became 101.7% after the second lengthening. Finally, it decreased to 82.9% at the last follow-up. Annual bone growth rate decreased after the first and second lengthening. Especially after the second lengthening, bone growth remarkably decreased. There were no complications except for pin-site infections at the first lengthening, whereas contracture of the elbow joint and callus fracture occurred at the second lengthening. Our study showed growth retardation occurred after bone lengthening and that the second lengthening resulted in remarkable growth retardation. We recommend delaying the second lengthening until the skeletal growth stops. Our series is small in number and we must investigate the influence of other factors (age, effect of the previous centralization, the amount of length, etc.). Further investigation will be needed to get firm conclusion. Level IV.

An anatomic study of coronoid cartilage thickness with special reference to fractures

Current coronoid fracture classification systems are based on fragment size and configuration using plain radiographs and/or computed tomography (CT). During surgery, coronoid fracture fragments appear much larger than anticipated because cartilage is radiolucent and therefore not accounted for with preoperative imaging. The purpose of this imaging study was to quantify the articular cartilage thickness of the coronoid, with reference to coronoid fractures. Twenty-four cadaveric ulnae were dissected, imaged with CT, and analyzed by use of image analysis software. Thirteen identifiable landmarks were chosen on the coronoid, olecranon, and proximal radioulnar joint to measure articular cartilage thickness. Intraobserver reliability and interobserver reliability were determined. Cartilage thickness was highest at the coronoid tip, with a mean of 3.0 mm (range, 1.7-4.6 mm). Cartilage thickness at the tip correlated inversely with age (P < .01) and correlated strongly with overall ulnar height and ulnar length (P < .05). All measurements had excellent intraobserver and interobserver reliability. The thickness of cartilage on the coronoid tip is not inconsequential. The results of this study indicate that a 2-mm coronoid tip fracture on CT scan may actually appear to be a mean of 5 mm thick when viewed at the time of surgery. Clinically, this is important because it may alter the classification, the decision to treat, or the type of fixation used. Importantly, biomechanical cadaveric studies assessing coronoid injuries have incorporated cartilage thickness into coronoid size measurements when creating simulated fractures; therefore, it is critical that the conclusions of such biomechanical studies be scrutinized with regard to their clinical recommendations. Surgeons should be aware of these discrepancies.

Expression of Leptin, Leptin Receptor, and Connective Tissue Growth Factor in Degenerative Disk Lesions in the Wrist

The purpose of this study was to identify whether leptin and connective tissue growth factor (CTGF) occur in the degenerative fibrocartilage disk and whether cartilage cells express leptin receptors. The study included 23 patients diagnosed with degenerative articular disk tears of the triangular fibrocartilage (TFC) (Palmer type 2C). Patients were divided into 2 groups based on ulna length: 1 group consisted of patients with an ulna-positive variance (group A), and the other group included patients with ulna-negative or -neutral variance (group B). After arthroscopic debridement of the TFC, histologic sections of biopsy specimens were prepared. The biopsy specimens were immunohistochemically analyzed, and the quantity of leptin-, CTGF-, and leptin receptor-positive cells was assessed. Cells positive for leptin, leptin receptor, and CTGF were found. The number of cells positive for leptin was significantly increased in specimens of patients with an ulna-negative variance (group B). In contrast, no significant difference was found for leptin receptor and CTGF in biopsy specimens of patients with ulna-positive or ulna-negative/neutral variance. The inner, middle, and outer zones of the disk do not express significantly different quantities of marker-positive cells. Degenerative fibrocartilage disk tissue cells exhibit leptin receptors and are exposed to the markers leptin and CTGF, providing evidence of a local paracrine system and regenerative processes. Cells of disks from patients with an ulna-neutral/negative length express significantly higher numbers of leptin-positive cells. Level II, diagnostic study.

The primary feather lengths of early birds with respect to avian wing shape evolution

We examine the relationships between primary feather length (f(prim)) and total arm length (ta) (sum of humerus, ulna and manus lengths) in Mesozoic fossil birds to address one aspect of avian wing shape evolution. Analyses show that there are significant differences in the composition of the wing between the known lineages of basal birds and that mean f(prim) (relative to ta length) is significantly shorter in Archaeopteryx and enantiornithines than it is in Confuciusornithidae and in living birds. Based on outgroup comparisons with nonavian theropods that preserve forelimb primary feathers, we show that the possession of a relatively shorter f(prim) (relative to ta length) must be the primitive condition for Aves. There is also a clear phylogenetic trend in relative primary feather length throughout bird evolution: our analyses demonstrate that the f(prim)/ta ratio increases among successive lineages of Mesozoic birds towards the crown of the tree ('modern birds'; Neornithes). Variance in this ratio also coincides with the enormous evolutionary radiation at the base of Neornithes. Because the f(prim)/ta ratio is linked to flight mode and performance in living birds, further comparisons of wing proportions among Mesozoic avians will prove informative and certainly imply that the aerial locomotion of the Early Cretaceous Confuciusornis was very different to other extinct and living birds.