The calcaneus is the largest tarsal bone in the human body, primarily composed of cancellous bone, surrounded only by a thin layer of cortical bone. When standing, the calcaneus is positioned at the lowest point, where gravity causes slow blood return, facilitating bacterial colonization and proliferation. Particularly in the central region of the calcaneal body, the triangular area with sparse trabeculae contains abundant bone marrow, making it a structurally weak point and thus a common site for hematogenous osteomyelitis of the calcaneus.

bubble_chart Pathological Changes

After the closure of adult epiphyses, hematogenous osteomyelitis often occurs in the vertebrae, ilium, or calcaneus where red bone marrow is concentrated. Lesions form there and spread outward. Since the calcaneal periosteum is tightly and firmly attached, large subperiosteal abscesses rarely form before the pus breaks through. Once the cortex is perforated, a sinus tract can easily develop.

bubble_chart Clinical Manifestations

Calcaneal osteomyelitis has an acute onset and is often accompanied by high fever and swelling of the calcaneus. Due to increased intraosseous pressure, there is severe pain, tenderness, and percussion pain in the calcaneus. Early tomography or CT scans may reveal focal areas of decreased density. Since this area consists of cancellous bone with rich blood supply, sequestrum formation is rare. As the disease progresses, increased calcium deposition and new bone formation may occur, leading to elevated bone density.

bubble_chart Treatment Measures

Similar to acute osteomyelitis in other parts, in addition to the use of effective broad-spectrum antibiotics, early fenestration and drainage are performed to reduce intraosseous pressure and prevent the spread of infection. The lesion should be gently curetted, avoiding forceful scraping, as this may excessively {|###|} injure the cancellous bone, create a large bone cavity, or expand the lesion. Since the calcaneus is a weight-bearing unit of the human body, early activity is not advisable after surgery. Weight-bearing walking should only begin after new bone formation.

Calcaneal osteomyelitis is classified as a special type or location of osteomyelitis and discussed separately because conventional foot incisions and surgical methods often yield unsatisfactory results. Medial or lateral foot incisions are only used for soft tissue abscesses or "fenestration" drainage in acute calcaneal osteomyelitis. For chronic calcaneal osteomyelitis, a special incision on the plantar surface of the heel (metatarsus) is required. Typically, making an incision on the plantar metatarsal surface is contraindicated because plantar scarring can cause pain during weight-bearing. Instead, the Gaenslen incision is used for exposure, involving a longitudinal incision precisely along the midline of the plantar heel. This incision starts at the level of the base of the fifth metatarsal bone and extends posteriorly to the distal end of the Achilles tendon. The calcaneus is then split longitudinally to remove the lesion. This method is highly effective for treating refractory chronic calcaneal osteomyelitis, providing excellent drainage and a high cure rate. After wound healing, the bilateral skin flaps invert and form a heel pad, preventing pain during weight-bearing. Even if occasional unevenness occurs on the plantar surface of the heel, the use of shoe inserts generally does not affect walking.