Hypertrophic Scar Prosthetic Pressure in Burn Amputee

Amputation following burn injury is uncommon. Major amputations following burn injury differ substantially from those performed in diabetic or vascular populations: burn-injured amputees are generally healthier, residual limb segments are longer, muscle flaps create bulkier stumps, and the residual limbs often present with hypertrophic scarring and contractures.

However, multiple complications may develop in individuals with burn-related amputations, including residual limb pain, edema, sensory disturbances (hypo- or hypersensitivity), heterotopic ossification, and recurrent wounds.

Pressure therapy has been widely used in burn rehabilitation to treat hypertrophic scars. It is believed to promote scar maturation by reducing mechanical tension. However, no studies to date have quantified the pressures exerted on hypertrophic scars of amputees with burn injuries when wearing their prosthetic liner or full prosthesis. This knowledge gap is critical, as pressures exceeding 40 mmHg can compromise capillary perfusion and cause pain, blistering, or tissue necrosis, which are risks that are exacerbated in grafted or flapped tissues predisposing them to skin breakdown.

Studies conducted in non-burn amputee populations have demonstrated that pressure distribution within a prosthetic socket varies significantly depending on socket design and materials. Reported interface pressures typically range from 40 kPa to 250 kPa (approximately 300-1875 mmHg). Measurement conditions also influence results, as pressures differ during static standing compared with dynamic gait. Liner thickness further affects these values; for example, increasing liner thickness by 4 mm has been shown to reduce peak pressures by approximately 18%. These findings highlight the importance of assessing pressure under realistic conditions, with the complete prosthetic system in place.

Clinically, it is often observed that hypertrophic scars covered by a prosthesis tend to flatten, become less erythematous, and appear more mature than adjacent uncovered scars. This observation led to the current research question and the hypothesis that prosthetic-induced pressure exceeds the pressure that is generated by standard pressure garments. Furthermore, it raises the question of whether residual limb wounds in this population may result from localized peak pressures within the prosthetic socket.

The objective of this pilot study is to improve understanding of prosthesis-residual limb interactions in burn-injured amputees and to assess the feasibility of measuring these interactions using objective pressure assessment tools.

This study is a prospective, minimal-risk, pilot observational feasibility study using a repeated-measures design. The study involves non-invasive interface pressure measurements obtained under usual prosthetic use conditions in adults with burn-related amputations. No therapeutic intervention or modification to standard clinical care will be introduced. The primary objective is to quantify prosthesis-induced interface pressures at predefined residual limb sites. The secondary objectives are to evaluate the feasibility, reliability, and acceptability of pressure measurement tools in this specific clinical population.