SKINTED: A Rare Complication After Total Knee Arthroplasty

Abstract

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.

Keywords: Dermatitis; Hypoesthesia; Infrapatellar branch of the saphenous nerve; Neuropathy; SKINTED; Total knee arthroplasty.

Figure 1

(a) Illustration of the left knee showing saphenous nerve descending along the medial side of the knee and its infrapatellar branch crossing the midline between the patella and tibial tubercle. In this figure, 2 branches cross the midline, which is the most commonly seen branching pattern. (b) Illustration of the 9 left knee showing area of hypoesthesia after TKA midline incision transecting the infrapatellar branch.

Figure 2

Photograph of the right knee showing a scaly erythematous plaque lateral to the midline scar.

Figure 3

Photograph of the right knee showing large hyperpigmented patch lateral to the midline scar.

Figure 4

Photograph of right knee showing scaly erythematous patch lateral to the midline scar.

Figure 5

Photomicrograph (H&E stain, ×100 magnification) showing hyperkeratosis with basal vacuolar degeneration along with perivascular lymphocytosis in superficial dermis.