1. Introduction
Surgery of the knee, injury to the infrapatellar branch of the saphenous nerve, traumatic eczematous dermatitis (SKINTED) a rare but clinically important postsurgical neurodermatitis. SKINTED is a site and procedure specific term that is characterized by eczematous eruption on the denervated area in the lateral side of the total knee arthroplasty incision scar. The standard surgical approach for total knee arthroplasty (TKA) is a midline skin incision with medial parapatellar arthrotomy (1). During this approach, the infrapatellar branch of the saphenous nerve (IPBSN) is at particular risk of traction or transection injury because of its superficial and variable course and branching pattern (figure 1) (2, 3). Iatrogenic injury to IPBSN leads to an area of paresthesia, hypoesthesia or complete anesthesia lateral to the incision scar (2, 3). IPBSN is a purely sensory nerve that arises from the saphenous nerve and crosses from the medial to the lateral side below the patella and supplies cutaneous sensation to the anterior area of the knee (2, 3). Beyond its sensory function, cutaneous neural input is essential for maintaining skin homeostasis, barrier integrity, and neuroimmune modulation.
Disruption of these neurocutaneous pathways contributes to the pathogenesis of SKINTED, as denervated skin exhibits altered cytokine signaling, increased trans epidermal water loss, and heightened inflammatory responsiveness (4, 5, 6). Although cutaneous sensory changes following TKA are well documented, the localized eczematous dermatitis within this denervated region remains underrecognized (6). Despite its characteristic dermatome-specific distribution, SKINTED is often initially misdiagnosed as contact dermatitis (allergic or irritant), metal hypersensitivity, or a superficial surgical site infection. As global TKA volume continues to rise, awareness of this complication is essential for orthopedic surgeons and dermatologists to avoid unnecessary diagnostic investigations and inappropriate treatment.
2. Case Presentation
A 73-year-old woman was referred to our dermatology clinic for evaluation of a red, itchy area on the lateral side of her right knee. The lesion appeared 3 months after undergoing total knee arthroplasty (TKA) for severe osteoarthritis. The patient reported no other skin issues or systemic symptoms.
Her medical history was significant for hypertension and hyperlipidemia, both of which were well-controlled with losartan and atorvastatin. She denied any personal or family history of atopic dermatitis, allergies, or prior dermatologic diseases. She had experienced no postoperative infectious complications or adverse reactions to dressings. On physical examination an erythematous scaly plaque with discrete papules lateral to the healed midline incision scar was observed (figure 2). Sensory  assessment demonstrated  sensory  loss  in light -touch and pinprick tests within the affected area. There were no signs of warmth, edema, or fluctuation. The remainder of the cutaneous examination was normal. The function of the replaced knee was normal. Laboratory investigations, including complete blood count and inflammatory markers, were within normal limits. Based on the patient's history of recent TKA, eczematous plaque overlying the anesthetic area on the lateral side of the midline TKA scar (consistent with the distribution of the IPBSN), normal laboratory parameters, and absence of relevant exposures, the diagnosis of SKINTED was made. The patient was treated with oral cetirizine 10 mg daily and topical fluocinolone acetonide applied twice daily. Pruritus and skin lesions resolved two and five weeks after the treatment respectively. She experienced gradual, partial improvement in sensation over 10 months.


Figure 1. Anterior view of the right knee joint. The IPBSN arises from saphenous nerve and crosses from medial to lateral side below the patella. (Prepared by Authors, 2026).



Figure 2. Erythematous scaly plaque with discrete papules lateral to the healed scar of TKA. (Prepared by Authors, 2026).