[The posttraumatic osteomyelitis in guinea-pigs (author's transl)]

Area of Science:

• Orthopedics
• Infectious Diseases
• Immunology

Background:

• Posttraumatic osteomyelitis is a challenging complication of bone fractures.
• Intramedullary pinning is a common surgical technique for fracture stabilization.
• The immunological consequences of intramedullary pinning in the context of infection are not fully understood.

Purpose of the Study:

• To develop and characterize a guinea pig model of posttraumatic osteomyelitis.
• To evaluate the impact of intramedullary pinning on the healing and chronicity of osteomyelitis.
• To assess the immunological response, specifically opsonic activity, following intramedullary pinning and infection.

Main Methods:

• Surgically fractured femurs in 120 guinea pigs.
• Groups received either no immobilization or intramedullary pinning.
• Subgroups were infected with Staphylococcus aureus or Escherichia coli, or served as non-infected controls.
• Follow-up included clinical evaluation and immunological studies (bacterial ingestion, opsonic activity) over 12 months.

Main Results:

• Infected animals predominantly developed acute osteomyelitis.
• Without intramedullary pinning, a few cases healed within three months; most became chronic.
• Intramedullary pinning was associated with chronic osteomyelitis persisting for one year.
• A marked depression in opsonic activity was observed within 35 days post-pinning, with statistically significant differences across groups.

Conclusions:

• Intramedullary pinning in a posttraumatic osteomyelitis model promotes chronicity.
• The surgical intervention significantly impairs immune function, specifically opsonic activity.
• This model provides insights into the pathogenesis and immunological challenges of posttraumatic osteomyelitis.