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 muscle contractures. Our study indicated a clinical potential cause of hallux rigidus and challenged the many aetiological theories. It could influence the choice of surgical procedure for the treatment of early grades of hallux rigidus

Painful peroneal spastic flatfeet without coalition or other known etiologies in adolescence, remains a difficult condition to treat. We present eight such cases with radiological and surgical evidence of bony abnormalities in the lateral subtalar region just anterior to the posterior facet. All patients had presented as tertiary referrals with recalcitrant pain and had undergone a trial of orthotics and physiotherapy. Diagnostic workup included a clinical and radiographic evaluation. Clinical examination consisted of gait examination, foot alignment, range of motion, torsional profile of the lower limbs and marking of symptomatic foci. All patients had standing weightbearing anteroposterior and lateral projections of the foot and ankle, CT and/or MRI scans of the foot. Coalitions and other known intra-articular pathologies like subtalar arthritis were ruled out. All patients had bilateral flatfeet but unilateral peroneal spasm. All patients had an accessory anterolateral talar facet (ATF) which was arising as an anterior and distal extension of the lateral process of the talus. This caused lateral impingement between the facet and the calcaneum, confirmed by bone edema around the sinus tarsi and marked at the apex of the angle of Gissane on MRI scans. All patients had stiff subtalar joints with very limited movement under anaesthesia, indicating peroneal muscle contracture. Patients were treated with a combination of facet excision, fractional peroneal and gastrosoleus lengthening and calcaneal lengthening to correct the flatfoot and prevent lateral impingement

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 (sd 2.0, (12 to 19), which increased to 17.1 mm (sd 1.8, (14 to 20) after division of the midline raphé. Division at a distal level resulted in a mean lengthening of 21.0 mm (sd 2.0, (18 to 25), which increased to 26.4 mm (sd 1.4, (24 to 29) after division of the raphé. These differences were significant (p < 0.001).

Cite this article: Bone Joint J 2014; 96-B:778–82.