Lengthening of the conjoined tendon of the gastrocnemius
aponeurosis and soleus fascia is frequently used in the treatment
of equinus deformities in children and adults. The Vulpius procedure
as described in most orthopaedic texts is a division of the conjoined
tendon in the shape of an inverted V. However, transverse division
was also described by Vulpius and Stoffel, and has been reported
in some clinical studies. We studied the anatomy and biomechanics of transverse division
of the conjoined tendon in 12 human cadavers (24 legs). Transverse
division of the conjoined tendon resulted in predictable, controlled
lengthening of the gastrocsoleus muscle-tendon unit. The lengthening
achieved was dependent both on the level of the cut in the conjoined
tendon and division of the midline raphé. Division at a proximal
level resulted in a mean lengthening of 15.2 mm ( Cite this article:
Hallux rigidus was first described in 1887. Many aetiological factors have been postulated, but none has been supported by scientific evidence. We have examined the static and dynamic imbalances in the first metatarsophalangeal joint which we postulated could be the cause of this condition. We performed a finite-element analysis study on a male subject and calculated a mathematical model of the joint when subjected to both normal and abnormal physiological loads. The results gave statistically significant evidence for an increase in tension of the plantar fascia as the cause of abnormal stress on the articular cartilage rather than mismatch of the articular surfaces or subclinical