The composite extensor retinaculum cutaneous flap: an anatomical cadaveric study

**Background**: Complex digital extensor tendon injuries are difficult to manage when adhesion formation and stiffness prevail. Vascularised tissue to reconstruct the skin and extensor defect would be the ideal reconstruction in both the acute and delayed settings. This anatomical study evaluates vascular supply to a suitable composite flap comprising skin, subcutaneous tissue and extensor retinaculum. **Methods**: An anatomical study of 18 cadaveric upper limbs was conducted to investigate the technical feasibility of a composite flap prior to its clinical application. The anterior (n=9) or posterior (n=9) interosseous artery was exposed and selectively injected with a coloured dye. Specimens were then dissected to raise the proposed composite flap of extensor retinaculum and the overlying integument. Specimens were subsequently assessed by digital subtraction angiography to evaluate the corresponding microvascular supply to the composite flap. **Results**: The anterior and posterior interosseous arteries supplied the extensor retinaculum through a dense network of vessels with choke anastomoses. The skin overlying the extensor retinaculum was predictably supplied by either artery through the perforator vessels between the fourth and fifth extensor tendon compartments. **Conclusion**: A composite unit of skin and extensor retinaculum can be harvested on either the anterior or posterior interosseous arteries. It can be employed for simultaneous vascularised tendon and skin reconstruction.