Autonomic Denervation Dermatitis: A Relatively Undocumented 'ADD'itional Complication of Total Knee Replacements and Other Surgeries Around the Knee

Arriving at SKINTED (Surgery of the Knee, Injury to the Infrapatellar Branch of the Saphenous Nerve, Traumatic Eczematous Dermatitis): A Case Report

Surgery of the knee, injury to the infrapatellar branch of the saphenous nerve, traumatic eczematous dermatitis (SKINTED) is a postsurgical localized dermatitis specifically linked to total knee arthroplasty (TKA). It is due to autonomic denervation following surgically inflicted nerve injury. It develops several months to years following a surgical trauma. It is being referred to by various names in the literature. Locoregional immune dysfunction due to lymphatic injury after surgery is the currently accepted theory. It must be distinguished from atopic dermatitis, allergic contact dermatitis/sensitization induced by topical medications or implanted metal hypersensitivity dermatitis, and post-traumatic eczema/dermatitis. We present a case of an elderly female patient in her 50s with dry eczematous lesions over the lateral aspect of the surgical incision over both knees developed three months following bilateral total knee replacement (TKR) done in view of osteoarthritis. The patient responded well to topical corticosteroid and emollient treatment. We have also reviewed the literature to provide an overview of potential concepts of etiopathogenesis described in the literature and to clear up any ambiguity surrounding various labels given to this entity.

Neuropathy Dermatitis: An Underdocumented Complication Following Total Knee Arthroplasty

Background

Midline surgical incision used in Total Knee Arthroplasty (TKA) is associated with iatrogenic injury to the infrapatellar branch of the saphenous nerve, which leads to neuropathic dermatitis around the healed surgical scar. There are very few studies with a limited number of cases that have reported this complication. We evaluated the incidence of neuropathic dermatitis and its implication for the functional outcome in TKA patients.

Methodology

Patients who underwent primary TKA between 1 January 2010 and 31 August 2019 and presented in follow-up with sensory disturbances and skin lesions adjacent to the surgical incision were evaluated in this study.

Results

A total of 3318 patients with 4282 TKAs were included, of which 188 patients presented with the clinical picture of neuropathic dermatitis. There were 136 females and 52 males with a mean age of 67.13 years (range 37-92 years). The mean duration from surgery to the appearance of skin lesions was 4.4 months (range 2-6 months), and they resolved at a mean duration of 7.67 (range 6-12) weeks. In our study, we found an incidence of 5.52%. All these patients had a stable and well-functioning knee at the time of presentation of the lesion with a mean Knee Society Score (KSS) of 92 (range 84-96).

Conclusion

In our study, we found the incidence of neuropathic dermatitis to be 5.52%, without any long-term implication on the functional outcome of operated knees. For a self-limiting complication of midline knee incision of TKA, it either resolves on its own or requires a short duration of topical steroid application.

SKINTED: an uncommon cutaneous complication of total knee replacement

Surgery of the knee, injury to the infrapatellar branch of the saphenous nerve, traumatic eczematous dermatitis (SKINTED) involving the skin lateral to the surgical incision/scar area is a site- and procedure-specific diagnosis associated with total knee replacement surgery. It results from autonomic denervation following surgical trauma to the nerve and occurs months to years after surgical trauma. It needs to be differentiated from post traumatic eczema/dermatitis, neuropathic dermatitis and contact dermatitis/sensitization due to topical therapies or implant material. Herein, we report a case of 70-year-old woman having no preexisting medical or dermatological disorder of significance presenting with eczematous lesions around both knees lateral to the incision site developing few months after bilateral total knee replacement surgery. Treatment with twice daily application of betamethasone dipropionate 0.05% cream, gabapentine 100 mg/d PO and liberal use of bland emollient cream given over 2 months was remittive without recurrence during more than one year of follow up. Since its exact prevalence, pathophysiology and clinical course remain uncertain its awareness remains relevant to both dermatologists and orthopedic surgeons to address unnecessary anxiety and dissatisfaction of the patient.