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.

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

BACKGROUND

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.

METHODOLOGY

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.

RESULTS

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.

CONCLUSION

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.

SKINTED: A Rare Complication After Total Knee Arthroplasty

Background

Surgery of the knee, injury to the infrapatellar branch of the saphenous nerve, traumatic eczematous dermatitis is a neuropathic dermatitis specific to total knee arthroplasty (TKA), occurring around the healed surgical scar area. Very few case reports exist in orthopaedic literature regarding this rare skin complication after TKA. We report a series of cases and estimated the incidence of this condition in our institute.

Methods

During the 1-year period from January 2018 to December 2018, patients who have undergone TKA and later presented with skin lesions adjacent to the operated site were identified. Detailed history was taken, and full clinical examination was performed for all the reported cases.

Results

A total of 9 lesions in 8 patients were identified out of a total of 203 consecutive TKAs operated during the study period, with an estimated incidence of 4.4%. The mean age was 64 years (range, 58-78 years). The mean time from surgery to diagnosis was 4 months (range, 3-6 months).

Conclusions

This group of dermatitis caused due to surgical transection of the infrapatellar branch of the saphenous nerve during TKA is a rare cutaneous complication, with an estimated incidence of 4.4% from this study. Lesions typically appear lateral to the operative scar within an area of hypoesthesia. Lesions in all patients improved after topical steroid therapy with no recurrences at further follow-up. Arthroplasty surgeons should have awareness of this benign complication, thereby avoiding unwarranted additional workup and alleviating unnecessary psychological stress to the patient.