In search of the ideal periosteal flap for bone non-union: The chimeric fibula-periosteal flap.

Vascularised periosteal flaps may increase the union rates in recalcitrant long bone non-union. The fibula-periosteal chimeric flap utilises the periosteum raised on an independent periosteal vessel. This allows the periosteum to be inset freely around the osteotomy site, thereby facilitating bone consolidation. PATIENTS AND METHODS: Ten patients underwent fibula-periosteal chimeric flaps (2016-2022) at the Canniesburn Plastic Surgery Unit, UK. Preceding non-union 18.6 months, with mean bone gap of 7.5 cm. Patients underwent preoperative CT angiography to identify the periosteal branches. A case-control approach was used. Patients acted as their own controls, with one osteotomy covered by the chimeric periosteal flap and one without, although in two patients both the osteotomies were covered using a long periosteal flap. RESULTS: A chimeric periosteal flap was used in 12 of the 20 osteotomy sites. Periosteal flap osteotomies had a primary union rate of 100% (11/11) versus those without flaps at 28.6% (2/7) (p = 0.0025). Union occurred in the chimeric periosteal flaps at 8.5 months versus 16.75 months in the control group (p = 0.023). One case was excluded from primary analysis due to recurrent mycetoma. The number needed to treat = 2, indicating that 2 patients would require a chimeric periosteal flap to avoid one non-union. Survival curves with a hazard ratio of 4.1 were observed, equating to a 4 times higher chance of union with periosteal flaps (log-rank p = 0.0016). CONCLUSIONS: The chimeric fibula-periosteal flap may increase the consolidation rates in difficult cases of recalcitrant non-union. This elegant modification of the fibula flap uses periosteum that is normally discarded, and this adds to the accumulating data supporting the use of vascularised periosteal flaps in non-union.

A Rare Case of a Chemical Burn: Dithranol with Salicylic Acid.

A 16-year-old female with psoriasis presented to our Plastic Surgery Department with a significant chemical burn to the neck, upper torso and left cheek (TBSA 6%). She applied a concoction of cream prescribed by her dermatologist in her native country, Poland when she returned to the United Kingdom. A few hours after application she developed a burn with pH of 5. A review of the cream revealed a mixture of 19% dithranol and 5% salicylic acid. This combination is recognized for managing psoriasis, however the strength of dithranol in the combination given is of a high concentration (normally <3%). This alone can cause a burn to the skin if left for a prolonged period of time. Salicylic acid is an enhancer which augments the stability of dithranol and increases its penetration and efficacy. The concentration of 5% is also on the higher end. Our patient was admitted for pain relief and further irrigation till normalization of the pH which was achieved after 3 days. A worrying aspect in our patients' case is that she was given the cream to commence at home. High concentration preparation is normally commenced in a controlled setting under medical supervision.