Journal of Hand Surgery (European Volume)

Recently the International Federation of Societies for Surgery of the Hand replaced the Swanson scheme for classifying congenital upper limb anomalies with the Oberg, Manske, Tonkin (OMT) classification. This review explores the reasons for this change after nearly 50 years of using the Swanson classification. In particular, it documents the state of our understanding regarding genetics and limb development at the time Swanson generated his classification. It also describes the continued progress in clinical genetics and developmental biology. Such progress drives the need to embrace and incorporate these changes within a new classification scheme; one that will improve communication, diagnosis, and support further discovery of the pathogenesis of congenital hand anomalies.

The reconstruction of a congenital hypoplastic thumb usually involves release of a tight first web space, metacarpophalangeal joint stabilization, reconstruction of intrinsic muscle function, and extrinsic tendon reconstruction, as appropriate. Numerous surgical options and combinations are available, but the approaches vary among surgeons who work in the field of congenital hand surgery and the empirical evidence that allows for evaluation of the results of techniques is scarce. Both the pre-operative assessment and intra-operative findings of all thumb elements – bone, joints, and soft tissues – should be considered in the surgical decision-making and eventually define the methods of reconstruction. This article summarizes the different reconstructive options.

Mirror-image symmetry in limbs is normal in the vertebrate phenotype. Genetic and epigenetic factors regulate the differentiation, patterning, and development of the embryo and foetus. Growth after birth is influenced by hormonal and environmental factors such as nutrition. Limb size asymmetry in a child should trigger a search for associated pathology that may include neoplastic conditions, sequelae of injury, vascular, and neurogenic factors. Macrodactyly, part of the PIK3CA Related Overgrowth Spectrum, offers the physician a clinical challenge, while at the same time an opportunity to study morphology, histology, and more recently the molecular mechanisms from which the conditions arise. Collaboration between clinicians and basic scientists offers an exceptional opportunity for coordinated study and the potential for improved patient outcomes.

Macrodactyly is a rare condition in which fingers, hands or limb growth is unregulated, resulting in overgrowth of tissues in the affected extremities. It is critical to properly assess these extremities for signalling pathway, psychological impact and potential surgical intervention, to achieve the best possible outcome for each patient. Treatment approaches can vary, and patient and family expectations weigh heavily on care complexity. Common surgical procedures may include epiphysiodeses, osteotomies, debulking procedures, carpal tunnel releases, toe transfers and amputations. The selection and timing of these surgeries is a vital component of the approach, as delayed healing and excessive scarring may occur. The purpose of this review is to assist in the navigation of decision-making and surgical timing for patients presenting with overgrowth manifesting itself as macrodactyly.

Preaxial polydactyly is a congenital hand anomaly predominantly of sporadic occurrence, which is frequently associated with abnormalities of the Sonic hedgehog signalling pathway. In experimentally induced preaxial polydactyly, radial aplasia is also frequently observed. To determine if there is a correlation between preaxial polydactyly and radial aplasia, we induced ectopic Sonic hedgehog signalling during chicken limb development with application of a smoothened-agonist (SAG) or retinoic acid. Application of SAG caused malformations in 71% limbs including preaxial polydactyly (62%) and forearm abnormalities (43%). Retinoic acid application induced malformations in 56% of limb including preaxial polydactyly (45%) and forearm abnormalities (50%). Radial dysplasia and ulnar dimelia were observed in both experimental conditions. We demonstrate that ectopic Sonic hedgehog signalling may cause both preaxial polydactyly and predictable forearm anomalies and that these conditions could potentially be classified as one embryological group. We propose a unifying model based on known models of ectopic Sonic hedgehog signalling.

Evolutionary developmental pathology, a new biological field, connects the study of evolution, development and human pathologies. In radial polydactyly, traditional studies have focused mainly on skeletal anomalies. This study examines anatomical and operative records of 54 consecutive cases of radial polydactyly to investigate whether there is a consistent spatial correlation between muscles, tendons and bones and whether this reflects a link between the mechanisms that generate these structures. The data are explored in the context of two current models of limb development: the modularity and topology models. Autopod (hand) tendons and muscles are more predictable in terms of insertion site, supporting both topology and modularity models. Zeugopod (forearm) tendons are less predictable. Neither model universally predicts the anatomy in radial polydactyly. These observations provide evidence for the complexity of anatomy in radial polydactyly and the difficulty in predicting operative findings based on the level of skeletal duplication alone.

Despite being a rare congenital limb anomaly, triphalangeal thumb is a subject of research in various scientific fields, providing new insights in clinical research and evolutionary biology. The findings of triphalangeal thumb can be predictive for other congenital anomalies as part of an underlying syndrome. Furthermore, triphalangeal thumb is still being used as a model in molecular genetics to study gene regulation by long-range regulatory elements. We present a review that summarizes a number of scientifically relevant topics that involve the triphalangeal thumb phenotype. Future initiatives involving multidisciplinary teams collaborating in the field of triphalangeal thumb research can lead to a better understanding of the pathogenesis and molecular mechanisms of this condition as well as other congenital upper limb anomalies.

Triphalangeal thumb is a rare congenital anomaly in which the thumb has three phalanges. Clinical presentation of triphalangeal thumb can vary considerably and can be present in both hands or unilateral. The thumb can be long with a finger-like appearance. The presence of clinodactyly depends on the shape of the extra phalanx varying from wedge-shaped to rectangular. Various joints, ligaments, muscles, and tendons of the first ray can be hypoplastic or absent, with varying degrees of stiffness or instability. The aim of surgical treatment is to reconstruct or correct the anatomic anomalies to obtain greater function and a more acceptable appearance. In our series, operations varied from removal of the delta phalanx with ligament reconstruction to multiple osteotomies and rebalancing of soft tissues. Results in these often complex cases can be rewarding if the surgeon has sufficient knowledge of the underlying anatomic differences. This review summarizes our current concepts of presentation and management of the triphalangeal thumb.

Cleft hand or split hand foot malformation is a sequence of phenotypes, from a minor shortening of the central digit to a complete absence of the third ray and in the most severe cases, absence of two, three or four rays. It is a rare but spectacular presentation usually involving both hands and feet. Inheritance is mostly autosomal dominant but sporadic cases without family history are also reported, resulting from a de novo mutation/deletion/duplication. Intra-familial clinical variability is the rule, with incomplete penetrance. X-linked or autosomal recessive inheritance has also been described. To date, seven subgroups of split hand foot malformation have been identified and seven loci are currently known. Anatomical records have enhanced our knowledge of this group of disorders of the hands and feet and allowed us to improve surgical procedures and long-term outcome.

Thalidomide remains notorious as a result of the damage it caused to children born to mothers who used it to treat morning sickness between 1957 and 1961. The re-emergence of the drug to treat a range of conditions including erythema nodosum leprosum (a complication of leprosy) has led to a new generation of thalidomide damaged children being born in Brazil. Although thalidomide affects most of the developing tissues and organs of the body, the damage to the limbs is striking. Indeed phocomelia, the severe reduction or loss of the proximal long bones with retention of the distal hand/foot plate remains the stereotypical image of thalidomide. This review focuses on the type and range of damage thalidomide caused to the limbs, reviews current understanding of the mechanisms underlying thalidomide-induced limb malformations and outlines some of the challenges remaining in elucidating its teratogenicity.

Thalidomide embryopathy results from the ingestion of thalidomide in the first trimester during pregnancy, causing multiple forms of congenital abnormalities of variable severity that involve all systems. The skeletal findings most frequently affect the limbs, particularly the upper limbs and hands. Increasingly, several genetic disorders with similar birth defects have been identified. New cases of malformations owing to possible exposure to thalidomide continue to present through both historical and current usage. However, inadequate proof of ingestion, marked phenotypic variation and the possibility of an alternative genetic condition, hinder the diagnosis of thalidomide embryopathy. We introduce a ‘diagnostic algorithm for thalidomide embryopathy’ (DATE) diagnostic software that can potentially provide a numerical score for the likelihood of birth defects in an individual as being caused by exposure to thalidomide and to provide a differential diagnosis based on the pattern of malformation.