Abstract
The hand is a remarkable organ. As hand surgeons, however, most of us are interested in what may go wrong with the finished product rather than where it began during embryological development. Compared to other research fields, developmental biology of the hand probably ranks much lower in terms of research priority or interest among hand surgeons, perhaps even paediatric hand surgeons.
In 2010, Oberg, Manske and Tonkin proposed a new classification (OMT) for congenital hand differences (Oberg et al., 2010) as a possible replacement for Swanson’s classification, adopted by the International Federation of Societies for Surgery of the Hand (IFSSH) since 1964. Based entirely on developmental biology and the axes of development, it had become evident that these are the only unshakable foundations on which to classify congenital hand differences and perhaps the reason why the IFSSH chose to adopt this new classification. Or perhaps it was the first time a classification was designed after meaningful collaboration between surgeons and scientists.
The contents of this special issue are largely commissioned and peer-reviewed from contributors at the 14th Limb Development and Regeneration Conference in Edinburgh, held in 2017. These are integrated with clinical papers invited and edited by our editor Michael Tonkin. The new insights have been fascinating, adding several fresh perspectives to familiar conditions. For example, thumb polydactyly with radial aplasia is an almost unheard-of clinical entity but experimental evidence using chicken limbs has shown these conditions to share a common embryological origin, a finding reported by others in clinical cases (Al-Qattan, 2018). The article on cleft hand describes fascinating anatomical findings about the perfect formation of structures up to the level of the cleft, contributing to the ongoing debate about whether this anomaly arises from a central defect in the apical ectodermal ridge or aberrant apoptosis after normal formation of the digit. The radial polydactyly article combines the fields of surgery and evolutionary developmental pathology to propose novel models that may help to predict surgical findings when operating on the highly variable anatomy of thumb duplication. As mentioned, we have included clinical articles to accompany their respective developmental biology counterparts, for example, macrodactyly. Surely, the future of macrodactyly treatment must move beyond the limitations of surgery, for example, by manipulation of related signal pathways. Six years ago, we commemorated the 50th anniversary of the founding of the Thalidomide Society to remember the victims of this terrible tragedy and to ensure that lessons had been learned. These lessons remain relevant with new generations of thalidomide survivors being seen today as the drug continues to be used in certain countries.
What is the role of hand surgeons in developmental biology or genetics? Hand surgeons are in a pivotal position; we see the greatest number of patients and act as a valuable referral source. When we find a positive family history, we help direct genetic linkage studies. When we develop a habit of questioning why a condition occurs for every patient we see, valuable clues may be generated as to the pathogenesis of the deformity, allowing fundamental research questions to be asked. Such collaboration is priceless.
It is hoped that this special issue will be read widely not just by hand surgeons but also other sub-specialists, e.g. developmental biologists, geneticists and neonatatologists. My special thanks to Neil Vargesson and Megan Davey for inviting me to co-organize the limb development conference and to Geoffrey Hooper and Wendy Patterson for their infinite patience in the editorial process. I hope you will enjoy reading this issue as much as I have enjoyed editing it.