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

Infrapatellar branch of the saphenous nerve lies subcutaneously and supplies the anterolateral aspect of knee below the patella. It is extremely susceptible to iatrogenic injuries during the surgeries around the knee, mainly total knee replacements (TKRs). Post operatively the patients present with localised area of numbness and in some instances a traumatic eczematous reaction termed autonomous denervation dermatitis (ADD) is witnessed, leading to skin manifestations that range from a simple rash to extensive lesions. A review of literature was conducted with search of relevant articles from Medline (PubMed), Embase, and Scopus which discussed eczematous skin lesions secondary to total knee replacements. Additionally, we noted studies which described these lesions in other surgeries around the knee like arthroscopies and fracture fixations. Eight studies including atleast one case after TKR were reviewed. There was only one cohort study while the remaining included case reports and small case series. There were 69 cases of ADD appearing after TKR. The appearance of the skin lesions was lateral to the incision in 30/34 operated knees and on both sides of the incision in four knees after TKRs. Bilateral lesions were seen in only six patients of TKRs. There was no functional limitation caused by these lesions and they resolved either spontaneously or after using topical steroids. ADD is a relatively uncommonly reported complication of TKRs, which can reduce patient satisfaction and increase surgeon apprehension. Although all cases of nerve damage do not manifest as cutaneous lesions, steps to minimise the damage to the nerve intra operatively should be taken. The diagnosis requires a high index of suspicion, and should not be dispelled as a simple allergic reaction without adequate investigations. Patients should be counselled to alleviate unnecessary fear and apprehensions.