These are infections involving bones and joints. They also include infections that occur after orthopedic procedures (such as prosthesis placement or foreign bodies used during fracture treatment). The main types are as follows.

• Osteomyelitis
• Vertebral Osteomyelitis – Spondylodiscitis
• Septic Arthritis
• Prosthesis Infections

1. Osteomyelitis

This refers to bone infection. It is classified based on its mechanism of development or duration.

Acute osteomyelitis generally responds well to the antibiotics initiated and can be treated without surgical intervention. However, in chronic osteomyelitis, due to the necrotic (dead) bone tissue that forms, antibiotic treatment alone may not be sufficient, and surgical removal of this dead tissue may be necessary. The duration of antibiotic treatment for both acute and chronic osteomyelitis should be 4-6 weeks.

2. Vertebral Osteomyelitis - Spondylodiscitis

This is a difficult-to-treat infection that occurs in the bones of the spine. Early diagnosis is difficult due to its insidious onset and silent clinical course. If the infection causes nerve conduction disorders, surgical intervention is required.

3. Septic Arthritis

This is a joint infection and, if not treated appropriately, is one of the infections that threaten life. Every patient with joint pain and fever should be considered to have septic arthritis until proven otherwise, and treatment should be started promptly. Treatment should involve surgical debridement of the infected joint and antibiotic therapy. If this is not done, joint deformity develops in one out of three patients.

4. Prosthesis Infections

As the average age increases, the incidence of joint disorders, especially joint diseases called osteoarthritis, increases. The lifetime probability of developing osteoarthritis in the knee joint is 50%, and 50% of cases are diagnosed at age 55. This has increased the use of prostheses, which improve joint movement. However, as with any surgical procedure, the most important complication of prosthesis surgery is infection. The risk of infection varies depending on the location of the prosthesis surgery.

The risk of infection according to the type of prosthesis is as follows:

• Primary hip prosthesis: 0.5–1
• Knee prosthesis: 0.5–2
• Shoulder prosthesis: 0.5–1

Incidence is 1.5% for the first two years, then 0.5% (average lifetime incidence is 1-2%).

Treatment of prosthesis infections often involves a two-stage surgical procedure along with long-term antibiotic therapy. First, the infected prosthesis is removed and antibiotic-impregnated materials are placed in its place. During this surgery, a sample is always taken to identify the causative agent of the infection, and a 4-6 week course of antibiotic therapy is administered based on the agent's sensitivity. Once the infection is considered to be cured, the antibiotic-impregnated material is removed from the joint during a second surgery, and a new prosthesis is inserted.