Stage IV Pressure Injury
A pressure injury with visible tendon is classified as Stage IV. 1
Staging Criteria
Stage IV pressure injury is defined by full-thickness tissue loss with exposed or directly palpable bone, tendon, muscle, or ligament. 1 This represents the most severe category of stageable pressure injuries, where deep anatomical structures become visible through the wound. 2
The staging system distinguishes full-thickness ulcers based on the deepest tissue layer involved:
- Stage III: Full-thickness tissue loss exposing subcutaneous fat, but bone, muscle, and tendon are NOT visible or directly palpable 1
- Stage IV: Full-thickness tissue loss WITH exposed bone, muscle, ligament, or tendon 1
Key Clinical Features of Stage IV
Stage IV pressure injuries frequently involve additional complications beyond simple tissue exposure:
- Undermining and tunneling are common findings 1
- Osteomyelitis risk is significantly elevated when bone is exposed, with prevalence ranging from 17% to 58% in patients with Stage IV injuries 2
- Anatomical barriers are breached, increasing risk of contiguous spread of infection 2
Critical Staging Pitfall
Do not attempt to stage wounds covered by eschar or slough—these must be classified as "unstageable" until debrided. 1 The presence of necrotic tissue obscuring the wound base prevents accurate assessment of the deepest tissue layer involved, making staging impossible until adequate debridement is performed. 3
Clinical Implications
Stage IV pressure injuries carry significant morbidity and mortality implications:
- These injuries increase risk of both local and systemic soft tissue infections 2
- They contribute to high mortality rates in affected populations 2
- Surgical debridement and flap coverage are indicated for nonhealing Stage IV pressure injuries to achieve rapid closure, reduce pain, decrease infection risk, and improve quality of life 2