A puncture wound is defined as a wound whose depth is greater than its width. These injuries most commonly occur on the plantar surface of the foot after stepping on a sharp object.1,2 Despite the relatively innocuous-appearing skin wound, there is significant risk of infection and injury to underlying structures. Puncture wounds caused by high-pressure injection equipment and animal bites, and those involving exposure to body fluids have the potential for unique complications.
With puncture wounds, shear forces between the penetrating object and tissue result in tissue disruption, producing hemorrhage and devitalization of skin and underlying tissues. Inoculation of infectious organisms into the deeper tissues can occur from the penetrating object (with or without leaving behind a foreign body from the object or material that has been pierced)3 or from the skin surface. When the penetrating object is removed, closure of the small skin wound creates a favorable environment for the development of infection. The reported infection rate from plantar puncture wounds is approximately 6% to 11%.4,5 Furthermore, exploration of infected plantar puncture wounds finds foreign material in about 25% of patients.6
Most soft tissue infections from puncture wounds are caused by gram-positive organisms. Staphylococcus aureus predominates, followed by other staphylococcal and streptococcal species.4,7–10 Puncture wounds over joints can penetrate the joint capsule and produce septic arthritis. Those that penetrate cartilage, periosteum, and bone can lead to osteomyelitis. Pseudomonas aeruginosa is the most frequent pathogen isolated from plantar puncture wound–related osteomyelitis, particularly when the injury occurs through the rubber sole of an athletic shoe.6,9–11 The source appears to be Pseudomonas that colonizes the foam lining of athletic shoes.
Difficulty in visualizing and cleaning to the full depth of the injury contributes to the higher risk for infection for puncture wounds compared with other traumatic lacerations. Other host and wound factors are associated with delayed healing and/or infection (Table 44-1).12,13
Table 44-1 Risk Factors for Puncture Wound Complications |Favorite Table|Download (.pdf)
Table 44-1 Risk Factors for Puncture Wound Complications
- Patient characteristics
- Diabetes with or without microvascular complications
- Immunocompromised (acquired immune deficiency syndrome, steroids, chemotherapy)
- Peripheral vascular disease
- Wound characteristics
- Contaminated with soil or debris
- Containing foreign body
- Occurring outdoors
- Occurring through a shoe and/or sock
- Deeper penetration (jumping, falling, running)
Plantar puncture wounds of the forefoot are at risk for foreign body deposition and infection,6 and because most of the body weight is transmitted to the metatarsal heads during walking, a puncture in this area might penetrate more deeply than elsewhere on the sole and produce a higher rate of infection. However, case series of patients hospitalized with infected plantar puncture wounds both support9,14 and refute10 this theory.