Shape memory phenomenon whereby the metal changes its characteristics depending on the ambient temperature it is exposed to is well described in the metallurgical literature. In cold conditions (0–5° C) the alloy becomes plastically deformable and its shape can be changed at will, but would rapidly regain its original shape and strength at higher temperatures. This study assesses the effectiveness of shape memory staples as a method of internal fixation in foot and ankle surgery.

All patients who underwent foot and ankle surgery in which Memory® staples were used for fixation were included in the study. The patients were evaluated with regard to period of immobilisation in cast, period of restricted weight bearing and time to radiological joint fusion or union of osteotomy.

Memory® staples had been used in a total of 40 procedures; 13 procedures (6 MTPJ fusions, 7 Akin osteotomies) were done in the forefoot while the rest were carried out in the mid or hind foot. Bone grafting was used only in one hind foot arthrodesis. A strong arthrodesis or union was achieved in all the patients. The average time to fusion was 7.2 weeks (range 6–12) with an average period of immobilisation of 4.3 weeks (range 0–12). The average time to full weight bearing was 5.2 weeks (range 0–6). Breakage of the staple was noticed in one patient but the joint went on to unite satisfactorily. Staple back out or displacement was not noticed in any of the cases.

The early experience with the use Memory® staples in foot and ankle surgery is encouraging; we did not encounter any technical problems and there is a suggestion that these implants may reduce the time to fusion/ healing thereby reducing the recovery time following foot and ankle surgery.

Aim: Chevron osteotomy is a commonly performed procedure for the treatment of hallux valgus and results in AVN of the first metatarsal head in up to 20% of cases. This study aims to map out the arrangement of vascular supply to the first metatarsal head and its relationship to the limbs of the chevron cuts.

Methods: 10 cadaveric lower limbs were injected with an Indian ink – latex mixture and the feet dissected to evaluate the blood supply to the first metatarsal. The dissection was carried out by tracing the branches of dorsalis pedis and posterior tibial vessels. A distal chevron osteotomy through the neck of the metatarsal was mapped and the relationship of the limbs of the osteotomy to the blood vessels was recorded.

Results: The first metatarsal head was found to be supplied by branches from the first dorsal metatarsal, first plantar metatarsal and medial plantar arteries of which the first one was the dominant vessel in 8 of the specimens studied. All the vessels formed a plexus at the plantar – lateral aspect of the metatarsal neck, just proximal to the capsular attachment with varying number of branches from the plexus then entering the metatarsal head. The plantar limb of the proposed chevron cuts exited through this plexus of vessels in all specimens. Contrary to the widely held view, only minor vascular branches could be found entering the dorsal aspect of the neck.

Conclusion: The identification of the plantar – lateral corner of the metatarsal neck as the major site of vascular ingress into the first metatarsal head suggests that constructing the chevron osteotomy with a long and thick plantar arm exiting well proximal to the capsular attachment may decrease the incidence of AVN.