Osteomyelitis of the calcaneus can follow blood spread, a septic infection of the heel, traction with a calcaneal pin, or an open fracture. The calcaneus is a completely cancellous bone which never forms an involucrum and seldom an isolated sequestrum. Pus soon perforates its periosteum without destroying much of its cortex. The most practical operation, and some would say the only one, is to remove the whole of the patient's calcaneus to give him an ugly but surprisingly useful foot.
Fungi sometimes infect the calcaneus and cause multiple sinuses. If chemotherapy fails, as it usually does, try radical excision in early cases, and consider amputation in late ones (31.3, 56.6).
OSTEOMYELITIS [s8]OF THE CALCANEUS AND TALUS THE CALCANEUS ANAESTHESIA. You will need to lie the patient prone, which makes anaesthesia difficult (16.12). If possible, intubate him and control his ventilation. If this is not possible, give him a general anaesthetic and lie him on his side.
INCISION. Follow the general methods for osteomyelitis, in Sections 7.4 to 7.6. Apply a tourniquet.
If infection is limited to the pin track, and he is lucky, opening up and scraping out the granulation tissue from around the pin track may occasionally be all that he needs.
If you are draining a soft tissue abscess or want to remove a window from the cortex during the acute stage, you can approach his calcaneus from either side.
If his whole calcaneus is involved, remove it completely. Make a longitudinal incision right down to the bone, and shell it out. You cannot remove it from inside its periosteum, so strip this away from the soft tissues of his heel and remove the bone completely, either as a single piece or in several smaller ones.
Lie him prone with a support under his foot. Make a longitudinal incision exactly in the middle of his heel. Start it in the midline level with the base of his fifth metatarsal. Extend the incision proximally to split the distal end of his Achilles tendon for about 3 cm. Incise his plantar aponeurosis in a plane between his flexor digitorum brevis and his abductor digiti minimi.
CAUTION ! Start in the midline, stay close to bone and reflect everything you meet medially and laterally. In this way you will avoid important structures, especially his plantar nerves entering from the medial side of his foot.
POSTOPERATIVELY, allow the wound edges to collapse together, but don't suture them. Apply much gauze. Hold his ankle in a neutral position with a gutter plaster splint held with a crepe bandage. As his wound heals, start him walking with crutches; later he can progress to full weight-bearing. The edges of the scar will turn deeply inwards and split his heel into two cushions. If its surface is uneven, suggest that he pads his shoe.
THE TALUS He presents with a painful ankle. X-rays show an irregular dense talus. Sequestra are unusual. If you apply a below knee cast and give him an antibiotic for 3 weeks the infection will probably settle without surgery, but degenerative arthritis may follow. If he has severe persistent disease refer him for the removal of his talus.
Fig. 7-13 A SEQUESTRUM IN THE SKULL. This patient has a dense white sequestrum in his skull, which has moved forwards. He was reported as having osteomyelitis. Burns of the scalp are however the commonest cause of necrosis of the skull. Another cause is septic thrombophlebitis of the scalp, which causes it to necrose and expose the bone underneath. Kindly contributed by Gerald Hankins.