Congenital synostosis of the fourth and fifth metacarpals treated by free bone grafting from the fusion site

Simultaneous correction of the alignment and the shortening of the deformed little finger in congenital synostosis of the fourth and fifth metacarpals was accomplished by insertion of a wedge-shaped bone block harvested from the fusion site following transverse osteotomy of the fifth metacarpal. Correction can be performed simply and successfully without morbidity of the donor site when this technique is applied to suitable patients.     

Distraction osteogenesis of the craniofacial skeleton

In summary, distraction osteogenesis is a safe and effective means of achieving bone lengthening. These techniques were originally applied to the long bones of the extremities; over the past 10 years they have been effectively applied to the bones of the craniofacial skeleton. The new bone regenerate that is observed after distraction osteogenesis is stable, and relapse rates after skeletal advancement are believed to be lower than with conventional osteotomy and bone graft techniques. There is considerable variability in distraction protocols employed in clinical practice, including differences in the types of devices used and in the rate, rhythm, latency, and period of consolidation for distraction osteogenesis. The greatest application for distraction osteogenesis in the craniofacial skeleton has been with mandible lengthening, for which there is presently a 10-year clinical experience. Midfacial advancement is a newer application of distraction osteogenesis, for which clinical experience has been accrued over the past 5 years. This latter experience indicates that distraction osteogenesis is a viable treatment option for lengthening of the hypoplastic mandible and midface. These techniques have advantages over conventional means of bone graft and rigid fixation because of the quality of the bone regenerate, the decrease in the long-term relapse rate of the advanced bone segments in both the mandible and the midface, and the simultaneous soft-tissue elongation that accompanies the distraction process. Distraction osteogenesis is particularly applicable to the correction of severe deformities of the mandible and midface in children with developmental hypoplasia and syndromic craniosynostosis. However, growth is an added variable in this patient population. The amount of overcorrection in lengthening of the hypoplastic bone required to compensate for continued growth discrepancy of the adjacent facial bones is difficult to predict. Therefore, the families of these patients should be informed that many children will require repeated operations at a later age as they reach skeletal maturity.     

Morphological classification and sexual dimorphism of hyoid bone: new approach

Hyoid bone is a part of viscerocranium placed between the tongue root and thyroid cartilage to which it is connected by thyrohyoid membrane. Widely accepted morphological classification does not exist. Sexual dimorphism was analysed in this study and new guidelines for anatomical classification of hyoid bones based on anthropometric parameters were given. Total number of analysed bones was 70. The bones were classified into three groups: symmetrical U-type, symmetrical V-type and asymmetrical type according to the angle between greater horns and the proportion of greater horns length. In the females incidence of asymmetrical type is considerably higher than in the males, while the incidence of symmetrical V-type is lower The angle value that is on average higher in males may be the parameter indicating that in puberty hyoid bone, still not completely ossified, to some extent follows development of thyroid cartilage because of their close anatomical relation.     

Features of the structure of the metacarpal bones of athletes in different specialties

Metacarpal bones have been examined in hand X-ray photos of 125 sportsmen at the age of 17-18 years who go in for swimming (dynamic loading on the hand) and competitive gymnastics (static loading on the hand). Under the effect of systematic trainings, which are connected with an increased loading on the hand, a number of morphological changes take place in the metacarpal bones. A prolonged loading of the dynamic character delays the synostosis process in the distal parts of the forearm bones and contributes to lengthening the I, III and IV and to widening the I-V metacarpal bones. As demonstrate decreasing indices of compactness in the swimmers, the widening diaphisis of the metacarpal bones occurs at the expense of dilatation of the medullary cavity. The static loadings result in a greater delay of the synostosis processes in the upper extremity parts mentioned, in a greater width of the I-III, V metacarpal bones in boy-gymnasts. The increased index of compactness demonstrates that the widening diaphysis of the metacarpal bones takes place at the expense of thickening of the compact substance and narrowing of the medullary cavity.     

Late reconstruction of two total metacarpal bone defects using lengthening devices and a double-barrel osteocutaneous free parascapular flap

A case was presented in which the late reconstruction of left ring and little metacarpal bone defects was carried out using a lengthening device and a double-barrel osteocutaneous free parascapular flap. With this flap, up to 14 cm of nearly straight bone of a suitable width and length for the reconstruction of two metacarpal bones was raised safely. However, it required 3 months of lengthening to create enough space to insert the grafted bone because of the severe resistance of scar contracture and fibrous tissues.     

Growth and shaping of metacarpal and carpal cartilage anlagen: application of morphometry to the development of short and long bone. A study of human hand anlagen in the fetal period

A histological and morphometric analysis of human metacarpal and carpal anlagen between the 16th and 22nd embryonic weeks was carried out with the aim of studying the establishment of the respective anlage architecture. No differences in the pattern of growth were documented between the peripheral and central zones of the metacarpal epiphyses and those of the carpals. The regulation of longitudinal growth in long bone anlagen occurred in the transition zone between the epiphysis and the diaphysis (homologous to the metaphyseal growth plate cartilage in more advanced developmental stage of the bone). Comparative zonal analysis was conducted to assess the chondrocyte density, the mean chondrocyte lacunar area, the paired chondrocyte polarity in the orthogonal longitudinal and transverse planes, and the lacunar shape transformation in the metacarpal. In transition from epiphysis to diaphysis chondrocyte density decreased and mean lacunar area increased. No significant differences in the chondrocyte maturation cycle were observed between proximal/distal metacarpal epiphyses and the carpal anlagen. The number of paired chondrocyte oriented along the growth vector was significantly higher in both proximal/distal transition zones between epiphysis and diaphysis. Human metacarpals shared with experimental models (like mice and nonmammal tetrapods) an early common chondrocyte maturation cycle but with a different timing due to the slower embryonic and fetal developmental rate of human anlagen.     

Toward a realistic optoelectronic-based kinematic model of the hand: representing the transverse metacarpal arch reduces accessory rotations of the metacarpophalangeal joints

A kinematic model representing the versatility of the human hand is needed to evaluate biomechanical function and predict injury risk in the workplace. We improved upon an existing optoelectronic-based kinematic hand model with grouped metacarpals by defining segmented metacarpals and adding the trapeziometacarpal joint of the thumb. Eight participants performed three static postures (neutral pose, cylinder grip, cap grip) to evaluate kinematic performance of three different models, with one, two, and four metacarpal segment(s). Mean distal transverse metacarpal arch angles in the four-segment metacarpal model were between 22.0° ± 3.3° (neutral pose) and 32.1° ± 3.7° (cap grip). Representation of the metacarpals greatly influenced metacarpophalangeal joint rotations. Both the two- and four-segment metacarpal models displayed significantly lower metacarpophalangeal joint ‘supination’ angles (than the one-segment model) for the fourth and fifth fingers. However, the largest reductions were for the four- versus one-segment models, with mean differences ranging from 9.3° (neutral pose) to 17.0° (cap grip) for the fourth finger and 16.3° (neutral pose) to 33.0° (cylinder grip) for the fifth finger. MCP joint abduction/adduction angles of the fourth and fifth fingers also decreased with segmentation of the metacarpals, although the lowest magnitudes generally occurred in the four-segment model. Overall, the four-segment metacarpal model produced the lowest accessory rotations in non-dominant axes, and best matched previous radiological studies that found MCP joint pronation/supination angles were typically less than 10°. The four-segment metacarpal model, with improved anatomic fidelity, will better serve future studies of detailed actions of the hand in clinical or work applications.     

Metacarpophalangeal length changes in humans during adulthood: a longitudinal study.

Total lengths of the 19 diaphyseal hand bones were measured from standardized radiographs of healthy American whites as young adults (ca. 21 years) and again at ca. 55 years of age. The four hand-bone rows exhibit distinctive length changes: Distal and middle phalanges continue to increase significantly in length, proximal phalanges constitute a transition zone of little change, and metacarpals uniformly decrease in length. Clear-cut sex differences are noteworthy: Males change more (lose more in some bone rows, gain more in others) than females. Progressive elongation was greatest in the distal phalanges where apposition around the distal aspect ("tufting") is not constrained by a joint or epiphysis. Loss of bone length in the metacarpals by subchondral resorption is consistent with documented reductions in activity levels and grip strength with age, as well as diminished joint spaces which alter loading of the joints.     

On the track of the bog people

The amount of radiographically detectable cortical bone, as determined by measurements of the second metacarpal, was evaluated in 42 male and 45 female Guamanian Chamorros and compared with the degree of bony demineralization in U.S. Caucasians participating in the Baltimore Longitudinal Study on Aging of the Gerontology Research Center. All Chamorros were individually matched to the Caucasian participants for age, sex, and menopause status. Chamorros of both sexes showed bilateral asymmetry in bone measurements and in the amount of cortical bone. Both Chamorro and Caucasian males had longer second metacarpals and more cortical bone than females. Caucasian males, however, had longer and larger second metacarpals than Chamorro males. Despite differences in the length and total width, Chamorro and Caucasian participants generally showed no significant differences in the amount of cortical bone or percent cortical area in the second metacarpal, suggesting that larger bones may not always indicate greater cortical mass. Although cross-sectional data suggested apparent age differences in the onset and rate of bone loss between Chamorros and Caucasians, the numbers of participants were too small to allow meaningful age-by-age statistical comparisons.     

Safety and efficacy of botox injection in alleviating post-operative pain and improving quality of life in lower extremity limb lengthening and deformity correction

Background

Distraction osteogenesis is the standard treatment for the management of lower limb length discrepancy of more than 3 cm and bone loss secondary to congenital anomalies, trauma or infection. This technique consists of an osteotomy of the bone to be lengthened, application of an external fixator, followed by gradual and controlled distraction of the bone ends. Although limb lengthening using the Ilizarov distraction osteogenesis principle yields excellent results in most cases, the technique has numerous problems and is not well tolerated by many children. The objective of the current study is to determine if Botulinum Toxin A (BTX-A), which is known to possess both analgesic and paralytic actions, can be used to alleviate post-operative pain and improve the functional outcome of children undergoing distraction osteogenesis.

Methods/Design

The study design consists of a multi centre, randomized, double-blinded, placebo-controlled trial. Patients between ages 5–21 years requiring limb lengthening or deformity correction using distraction will be recruited from 6 different sites (Shriners Hospital for Children in Montreal, Honolulu, Philadelphia and Portland as well as DuPont Hospital for Children in Wilmington, Delaware and Hospital for Sick Children in Toronto, Ont). Approximately 150 subjects will be recruited over 2 years and will be randomized to either receive 10 units per Kg of BTX-A or normal saline (control group) intraoperatively following the surgery. Functional outcome effects will be assessed using pain scores, medication dosages, range of motion, flexibility, strength, mobility function and quality of life of the patient. IRB approval was obtained from all sites and adverse reactions will be monitored vigorously and reported to IRB, FDA and Health Canada.

Discussion

BTX-A injection has been widely used world wide with no major side effects reported. However, to the best of our knowledge, this is the first time BTX-A is being used under the context of limb lengthening and deformity correction.

Trial Registration

NCT00412035     

Articular constraint, handedness, and directional asymmetry in the human second metacarpal

The hypothesis that functional adaptation of joint surfaces to mechanical loading occurs primarily through change in mass, density, and structure of subarticular trabeculae (the "articular constraint" model) is investigated through an analysis of directional asymmetry among three separate bone compartments in the human second metacarpal. Measures of midshaft cross-sectional geometry, osteometry of the distal epiphysis, and subarticular trabecular microarchitecture of the distal epiphysis (assessed by high-resolution microcomputed tomography) were determined for 29 paired male and female metacarpals from a well-preserved nineteenth-century Euro-Canadian historic cemetery sample. For each measure, asymmetry was quantified using both mean-difference and confidence-interval methods. Both methods found a significant right-hand bias for measures of structural strength in midshaft geometry, as has been previously noted for this sample. Articular size, however, exhibits a right-hand bias only with regard to mediolateral, and not dorsopalmar, dimensions, a result that may reflect directional asymmetry in hand breadth at the distal palmar arch. The most striking asymmetries occur for subarticular trabecular microarchitecture. The right metacarpal head exhibits greater bone volume fraction, bone surface density, trabecular number, connectivity, and a more platelike rather than rodlike structure. These outcomes confer greater resistance to both axial compressive and shear strains for the metacarpal head at the metacarpophalangeal arthrosis. In all, these results confirm and extend previous research documenting structural asymmetries and limb dominance and are consistent with the concept of articular constraint. They also suggest a morphological signal through which functional asymmetry associated with handedness in fossil hominins may be investigated.     

Reduced trabecular bone mineral density and cortical thickness accompanied by increased outer bone circumference in metacarpal bone of rheumatoid arthritis patients: a cross-sectional study

Introduction

The objective of this study was to assess three-dimensional bone geometry and density at the epiphysis and shaft of the third meta-carpal bone of rheumatoid arthritis (RA) patients in comparison to healthy controls with the novel method of peripheral quantitative computed tomography (pQCT).

Methods

PQCT scans were performed in 50 female RA patients and 100 healthy female controls at the distal epiphyses and shafts of the third metacarpal bone, the radius and the tibia. Reproducibility was determined by coefficient of varia-tion. Bone densitometric and geometric parameters were compared between the two groups and correlated to disease characteristics.

Results

Reproducibility of different pQCT parameters was between 0.7% and 2.5%. RA patients had 12% to 19% lower trabecular bone mineral density (BMD) (P ≤ 0.001) at the distal epiphyses of radius, tibia and metacarpal bone. At the shafts of these bones RA patients had 7% to 16% thinner cortices (P ≤ 0.03). Total cross-sectional area (CSA) at the metacarpal bone shaft of pa-tients was larger (between 5% and 7%, P < 0.02), and relative cortical area was reduced by 13%. Erosiveness by Ratingen score correlated negatively with tra-becular and total BMD at the epiphyses and shaft cortical thickness of all measured bones (P < 0.04).

Conclusions

Reduced trabecular BMD and thinner cortices at peripheral bones, and a greater bone shaft diameter at the metacarpal bone suggest RA spe-cific bone alterations. The proposed pQCT protocol is reliable and allows measuring juxta-articular trabecular BMD and shaft geometry at the metacarpal bone.     

Natural markers in bone growth

Three features in the long bones, shown by radiograms, have been used as markers for the study of bone growth.

• (I) Transverse lines of arrested growth. Radiograms of six long limb bones from 1,576 individuals were investigated for clearness and persistence of these lines. Both ends of tibia and fibula showed very high frequency of suitable lines for markers, possibly also the distal end of femur and radius.
• (II) Notches in the base of second and fifth metacarpal bones. Measurements of growth from apex of the basal notch to the ends of the shaft were performed on serial hand radiograms. The proportion of growth from distal and basal ends averaged 87:13 in the second and 80:20 in the fifth metacarpal bones.
• (III) Nutrient canals. The initial point of ossification was determined by a prolongation of the nutrient canal intersecting the central axis of the medullary cavity. The proportion of growth from that point to distal and basal ends of the shaft averaged 68:32 and 64:36 for the second and the fifth metacarpal bones, respectively. These values are significantly different from the measurements obtained from the notches.

     

Robusticity and osteoarthritis at the trapeziometacarpal joint in a Bronze Age population from Tell Abraq, United Arab Emirates

Osteoarthritis (OA) is a progressive disease of the joints and can cause pain, reduced range of motion and strength, and ultimately loss of function at affected joints. Osteoarthritis often occurs at sites where biomechanical stress is acutely severe or moderate but habitual over the course of a lifetime. Skeletal remains from an Umm an-Nar tomb at Tell Abraq, United Arab Emirates (ca. 2300 BC), were recovered and represented over 300 individuals of all ages. The remains were disarticulated, commingled, and mostly fragmented. An analysis of 650 well-preserved adult metacarpal and carpal bones, from the tomb's western chamber, revealed that over 53% of the trapeziometacarpal joint facets showed signs of OA varying from mild to severe. The first and second metacarpals and trapezium bones were sided and evaluated for OA at the trapeziometacarpal joint articulations. Osteoarthritis was detected on 53% of the first metacarpals, 40% of the second metacarpals, and 57% of the trapezium bones. All specimens appeared enlarged, and the first metacarpals were assessed for sexual identification and robusticity. Eighty-five percent of the bones were probable males, and more than 80% of them had a robusticity index of 60 or higher. A strong correlation was found between OA, sex, and robusticity. High levels of OA and robusticity at the thumb suggest that the people of Tell Abraq were habitually involved in biomechanically challenging work with their hands.     

Allometric patterning in the limb skeleton of bats: Implications for the mechanics and energetics of powered flight

Allometric analysis was employed to compare linear dimensions of forelimb and hindlimb bones (humeri, radii, third and fifth metacarpals, third and fifth manual phalanges, femora, and tibiae) of 227 species of bats and 105 species of nonvolant mammals of varying degrees of phylogenetic affinity to bats. After accounting for body size, all forelimb bones are longer in bats than in nonvolant species, with the exception of humeri and radii of a few highly arboreal primates. Hindlimb bones are generally, but not uniformly, shorter in bats than in other mammals. For the humerus, radius, and metacarpals, midshaft diameters are greater in bats than in their comparably sized relatives. Proximal phalangeal midshaft diameters are statistically indistinguishable from those of other mammals, and distal phalanges show significantly reduced outer diameters. The pattern of relative reduction in wing bone diameters along the wing's proximodistal axis parallels the reduction in bone mineralization along the same axis, and a similar pattern of change in cortical thickness from the smallest wall thicknesses among mammals in the humerus and radius to the greatest wall thicknesses among mammals in the phalanges. The combination of altered cross-sectional geometry and mineralization appears significantly to reduce the mass moment of inertia of the bat wing relative to a theoretical condition in which elongated bones preserve primitive mammalian mineralization levels and patterns of scaling of long bone diameters. This intercorrelated suite of skeletal specializations may significantly reduce the inertial power of flight, contributing significant energetic savings to the total energy budgets of the only flying mammals. J. Morphol. 234: 277–294, 1997. © 1997 Wiley-Liss, Inc.     

Using the finite element method to model the biomechanics of the asymmetric mandible before, during and after skeletal correction by distraction osteogenesis

An approach was developed to evaluate the load transfer mechanism in the temporomandibular joint (TMJ) area before, during and after mandibular ramus elongation by distraction osteogenesis (DO). In a concerted approach using computer tomography, magnetic resonance imaging (MRI), and finite element analysis, three-dimensional numerical models based on a young male patient, with a dento-facial deformity were generated. The magnitude and direction of the muscle forces acting on the mandible were assessed using both values derived from the muscles volume and cross-section as retrieved from the MRI-scan data-sets and taken from the literature. The resistance of the soft tissue envelope towards elongation during the DO-phase was also included. The finite element analyses showed that before skeletal correction by DO the load transfer was asymmetrical with high peak stresses in the affected joint. Following ramus elongation a more symmetrical loading in TMJs was predicted. The reaction forces in the TMJs during DO were low.     

Using the finite element method to model the biomechanics of the asymmetric mandible before,during and after skeletal correction by distraction osteogenesis

An approach was developed to evaluate the load transfer mechanism in the temporomandibular joint (TMJ) area before, during and after mandibular ramus elongation by distraction osteogenesis (DO). In a concerted approach using computer tomography, magnetic resonance imaging (MRI), and finite element analysis, three-dimensional numerical models based on a young male patient, with a dento-facial deformity were generated. The magnitude and direction of the muscle forces acting on the mandible were assessed using both values derived from the muscles volume and cross-section as retrieved from the MRI-scan data-sets and taken from the literature. The resistance of the soft tissue envelope towards elongation during the DO-phase was also included. The finite element analyses showed that before skeletal correction by DO the load transfer was asymmetrical with high peak stresses in the affected joint. Following ramus elongation a more symmetrical loading in TMJs was predicted. The reaction forces in the TMJs during DO were low.     

Estimation stature from X-rays of metacarpals in the Turkish population

Determination of stature is as important as the determination of sex and age when analyzing and identifying the remains of skeletons. Stature, in an approximate and widespread manner, is determined by the femur and tibia, i.e. those long bones that affect stature directly. However, when long bones are not available or when they are found in a very badly preserved condition that does not permit any estimation on stature, then other bones of the body can also be used for this purpose. The aim of this study is to determine stature with the help of metacarpals in the Turkish population. In this study, by using the X-ray films of metacarpal bones of 100 females and 100 males, regression equations have been set up for 5 metacarpal bones. The coefficients of correlation existing between the metacarpal bones and stature, together with the standard errors of these equations, have been intensively examined in this study. The results of studies conducted by other researchers such as Musgrave & Harneja (1978) and Meadows & Jantz (1992) have been compared with the results of our study. As a result of this comparison, the difference existing between them has been found to be significant according to the results of the t-test (p < 0.05, p < 0.01 and p < 0.001). The significance of such results proves that the general body characteristics and body proportions of populations are differing from each other and therefore specific regression equations for the different populations have to be set up.     

Regulation of cell polarity in the cartilage growth plate and perichondrium of metacarpal elements by HOXD13 and WNT5A

The morphology of bones is genetically determined, but the molecular mechanisms that control shape, size and the overall gestalt of bones remain unclear. We previously showed that metacarpals in the synpolydactyly homolog (spdh) mouse, which carries a mutation in Hoxd13 similar to the human condition synpolydactyly (SPD), were transformed to carpal-like bones with cuboid shape that lack cortical bone and a perichondrium and are surrounded by a joint surface. Here we provide evidence that spdh metacarpal growth plates have a defect in cell polarization with a random instead of linear orientation. In parallel prospective perichondral cells failed to adopt the characteristic flattened cell shape. We observed a similar cell polarity defect in metacarpals of Wnt5a^−/− mice. Wnt5a and the closely related Wnt5b were downregulated in spdh handplates, and HOXD13 induced expression of both genes in vitro. Concomitant we observed mislocalization of core planar cell polarity (PCP) components DVL2 and PRICKLE1 in spdh metacarpals indicating a defect in the WNT/PCP pathway. Conversely the WNT/β-CATENIN pathway, a hallmark of joint cells lining carpal bones, was upregulated in the perichondral region. Finally, providing spdh limb explant cultures with cells expressing either HOXD13 or WNT5A led to a non-cell autonomous partial rescue of cell polarity the perichondral region and restored the expression of perichondral markers. This study provides a so far unrecognized link between HOX proteins and cell polarity in the perichondrium and the growth plate, a failure of which leads to transformation of metacarpals to carpal-like structures.