This prospective, observational cohort study evaluates the long-term outcomes of Regenerative Peripheral Nerve Interface (RPNI) surgery in patients with major lower extremity amputations suffering from symptomatic neuromas. RPNI is a surgical technique where the transected nerve end is implanted into a free autologous muscle graft to serve as a physiological target for reinnervation. The study aims to objectively assess the reduction in mechanical hypersensitivity using Pressure Pain Threshold (PPT) measurements via a digital algometer. Additionally, it monitors subjective neuropathic pain levels, functional mobility, and prosthesis satisfaction over a 24-month follow-up period compared to pre-operative baselines.
Age: Adults aged 18 to 70 years.
Amputation Status: Unilateral major lower extremity amputation (Transtibial, Transfemoral, or Knee Disarticulation).
Radiological Baseline: Absence of Heterotopic Ossification (HO) in the residual limb, confirmed by pre-operative X-rays (Walter Reed Classification Grade 0).
Neuropathic Pain: DN4 Questionnaire score ≥ 4.
CRPS: Diagnosis of Complex Regional Pain Syndrome (CRPS Type 1 or 2).
Concurrent Bone Surgery: Patients requiring simultaneous stump revision surgery (e.g., bone shortening, osteotomy, spur excision) or having existing HO (Walter Reed Grade > 0).
Systemic Conditions: Uncontrolled diabetes mellitus (HbA1c > 8.5%) or severe peripheral arterial disease compromising wound healing.
Cognitive Status: Cognitive impairment or psychiatric conditions preventing reliable completion of patient-reported outcome measures (PEQ, DN4).