1 Introduction

Total knee arthroplasty (TKA) is one of the most commonly performed orthopedic procedures,¹ with an excellent success rate and improvement in patients’ overall quality of life.² Unfortunately, although most patients experience significant improvement with a TKA, some experience pain or complications.³ There are approximately 9 % revision procedures, and the second leading cause of revision after TKA is the periprosthetic joint infection (PJI) with 14.8 % (of all revision) in the Worldwide Arthroplasty Registers.⁴ Less than 1 % of complications are related to allergies to implant components or cement constituents. They can be responsible for unresolved pain and their clinical manifestation may mimic an infection.⁵ Notwithstanding, an allergic skin reaction to sutures so severe that mimics an acute PJI after TKA has never been described in the literature to our knowledge.

We present a documented case of acute skin allergy to sutures resulting in redness, pain, warmth and swelling of the knee 1 week after TKA. Our case is the first reported with pathological anatomy sections confirming an allergic reaction to sutures. This article demonstrates, through the presentation of this case, that a purely cutaneous allergy can lead to an aggressive surgical revision which turned out to be unnecessary with a resulting negative impact on patient satisfaction.

The objective of the article is to show that allergic reaction should be included in the differential diagnosis of local soft tissue inflammation following TKA, which should trigger further investigation before surgical revision is considered.

2 Case report

We report the case of a 67-year-old female patient, suffering from obesity with a BMI of 44 (140 kg), severe obstructive sleep apnea (AHI 30/h) treated with CPAP therapy, hypertension and allergic asthma to dog and cat hair. The patient also underwent left TKA three years ago with satisfactory clinical knee function and no pain.

During orthopedic follow-up, the patient was diagnosed with primary right knee osteoarthritis, for which a cemented and posterior-stabilized total knee prosthesis was performed (ATTUNE® DePuy Synthes, Johnson & Johnson) in a private clinical practice. The initial post-operative course was without complication, the patient benefited from a standard physiotherapy protocol and was discharged on the 4th postoperative day, walking with crutches, without pain and with knee flexion up to 80°.

2.1

2.1 Clinical findings

On the 7th post-operative day, when the dressing was changed, a superficial and well-defined redness was visible around the surgical wound. There was no discharge or pain. Due to suspected allergy to the dressing material, the dressing was changed and oral antihistamine treatment was initiated. On the 10th post-operative day, the patient was referred to the local hospital emergency department with a marked increase in redness over approximately 20 cm, with a thermal gradient, swelling and pain. Additionally, the surgical wound showed early dehiscence, with a bulbous formation around (Fig. 1).

Close

Fig. 1 Photograph of the knee 10 days post-operative.

Export to PPT

2.4

2.4 Therapeutic intervention

The standard surgical procedure was performed with multiple tissue samples for bacteriological analysis as well as the exchange of the mobile components (polyethylene insert) which was sent for bacteriological analysis after sonication. Given the atypical macroscopic appearance of the cutaneous and sub-cutaneous tissues, samples were sent also for histopathological examination. After consultation with the hospital's infectious disease department, the patient was started on intravenous Meropenem 2g TID and was then switched to intravenous Linezolid 600mg BID which was stopped after the final bacteriological results. The seven tissue samples taken during the operation remained sterile after 14 days of incubation, as did the polyethylene insert after sonication. Cutaneous and sub-cutaneous samples sent for histopathology showed Wells-type eosinophilic cellulitis,⁶ particularly around the absorbable sutures (Figs. 2–4). A laboratory test (complete blood count) to assess the level of eosinophils in the blood was performed but was normal.

Close

Fig. 2 10× magnification, Hematoxylin and eosin stain Hyperplastic epidermis without atypia with significant perivascular, periannexal and interstitial inflammatory infiltrate, marked subepidermal edema.

Export to PPT

Close

Fig. 3 20× magnification, Hematoxylin and eosin stain Epidermal acanthosis without significant keratinocyte atypia, otherwise preserved, exudative scaling crust, important dermal inflammatory infiltrate with numerous eosinophils and with focal involvement of the dermal-epidermal interface.

Export to PPT

Close

Fig. 4 40× magnification, Hematoxylin and eosin stain Interstitial inflammatory infiltrate between mixed collagen fibers with numerous eosinophils, suggestive of eosinophilic cellulitis.

Export to PPT

2.5

2.5 Follow-up and outcomes

Initial follow-up was unremarkable with a well-healing surgical wound and a reduction in inflammation. The patient first complained of insomnia due to itching around the surgical site, which gradually improved. At 6 month's follow-up, the patient had no unusual complaints, was able to walk normally and the surgical wound showed no signs of inflammation (Fig. 5).

Close

Fig. 5 Anteroposterior and lateral X-rays of the knee 6 months post-operatively.

Export to PPT

At 1-year postoperatively, the patient still reports tolerable pain when walking and slight extra-articular swelling of the knee. Function is good, especially mobility, with full extension and 130° flexion, but overall patient-reported satisfaction is average due to persistent residual pain.

A SPECT-CT and scintigraphy confirmed that there were no other complications related to this TKA. Including no infection, component loosening or residual allergies around the implants.

The final diagnosis was an allergic skin reaction to sutures (Stratafix™ polydioxanone suture) mimicking an acute knee PJI.

3 Discussion

The aim of our study is to bring attention to the orthopedic community to allergic skin reactions to suture or dressing materials, rare and often misdiagnosed complications of TKA surgery.

We therefore suggest performing at least cutaneous and sub-cutaneous biopsies in patients admitted for DAIR surgery in the event of an atypical manifestation of PJI with significant skin changes at the surgical site.

The literature regarding documented acute allergy to suture material specifically in the patient after TKA is scarce. The clinical manifestation (redness, pain, and swelling) is similar to PJI or allergy/sensitivity to implant components or cement constituents, thus leading to difficulties in therapeutic decision making. Complications related to metal allergy in patients after TKA have a prevalence of approximately 1 %, with sensitivity to Nickel, Cobalt and Chromium being the most common.^7–9

We found few publications^10–17 describing local skin reactions mainly caused by dressing used for post-operative wound care. There are 5 reported cases of bullous pemphigoid described after TKA.^10–14 All reports documented a similar description of the intensely pruritic local rash with tense, fluid-filled blisters on an erythematous base at the surgical site. The onset of symptoms, their location, and their course varied. The diagnoses were confirmed by biopsies but the etiology was not clarified. The author's conclusions were to respond quickly in such a scenario by performing a skin biopsy and seeking a dermatological opinion.

Durando et al.¹⁵ reported 15 cases of skin rash around the surgical site in their cohort study of 912 patients. In these cases, Dermabond™ dressings were used. In two out of three cases who agreed to undergo patch testing (T.R.U.E. TEST®) a positive reaction to Dermabond™ developed.

Davis and Stuart¹⁶ reported a similar case resolved after four weeks of topical corticosteroid therapy.

Finally, Chan et al.¹⁷ reported three cases of allergic reactions following skin closure with Dermabond Prineo® out of 366 TKAs (1.8 %). Local reactions were similar and resolved with cephalexin (Keflex®) and topical corticosteroids between four and twelve weeks postoperatively. During a 1-year follow-up, no signs of PJI were noted.

An allergic-like skin reaction to sutures mimicking acute knee PJI has been barely described in the literature due to its very low incidence, the variability of clinical presentations and the difficulties of diagnosis.¹⁸

The formal diagnosis is made by histopathological analysis of the scar. This should be considered when there is suspicion of PJI and a surgical revision does not seem compatible with infection, in order to carry out, at a minimum, biopsies of the scar during the operation.

There is no consensus on how to investigate and treat suspected post-operative skin allergy and how to collect skin samples without surgical reintervention. In our case, we considered the possibility of acute post-operative infection too important to not revise surgically.

If PJI is suspected, the diagnostic strategy is well established. Parvizi et al.¹⁹ defined a score with major and minor criteria to determine the presence PJI.

Finally, in the case that we presented and according to the score established by Parvizi et al.,¹⁹ a primary diagnosis of acute PJI was established and a surgical revision according to DAIR protocol was performed as recommended.

It is then necessary to consider intraoperatively, depending on the surgeon's findings, whether to send the scar and the synovial membrane separately for histopathology to investigate for a possible metal or a skin allergy.

We also suggest, if timing allows, taking local skin biopsies, before proceeding with aggressive revision surgery, in the event that an allergic reaction is strongly suspected.

Even if currently the trend and the latest recommendations in septic surgery are toward rapid revision in suspected PJI at less than 2 weeks’ postoperatively (because the risk of biofilm formation becomes very high),²⁰ this case report should encourage orthopedic surgeons to think carefully about the possibility of an allergy before undertaking aggressive surgical revision in the face of a borderling presentation of PJI, particularly important when considering that an extensive synovectomy poses inherent risks for the patient by increasing the risk of hemarthrosis and postoperative pain.

In hindsight, with regard to this case, it would have been advisable to perform joint aspiration of synovial fluid and obtaining a dermatological consult for a possible skin biopsy. Finally, we would have performed a superficial surgical site revision and considered corticosteroid treatment.

4 Conclusion

In conclusion, an allergic reaction should be considered in an ambiguous skin reaction immediately postoperatively following prosthetic joint replacement and additional investigation carried out.

Larger retrospective studies could be conducted to investigate the impact of aggressive surgical revisions that ultimately resulted in an allergic skin reaction and their impact on clinical and functional outcomes and patient satisfaction.

This would allow more precise guidelines to be established and avoid unnecessary or overly aggressive surgical revisions, perhaps including the possibility of taking skin samples and performing a joint aspiration in case of diagnostic doubt in order to begin appropriate treatment.

Financial support and sponsorship

None.

Informed consent

The patient gave her written consent for the use of clinical findings including photographs or videos for scientific use.

Authors contribution

JG: Bibliography, wrote the article, correction, reference layout, submission, JGN: English translation, SG: Correction and arrangement of the different parts, English correction, JC: Bibliography, lead the project, operated the patient, took the pictures, retrieved laboratory and pathology data, proofreading.

Ethic approval

This study has been ethically validated and authorized by the commission for clinical research of the Neuchâtel hospital network (institutional ethics committee).

Ethical statement

The Human research Act (HRA) in Switzerland do not cover the study and publication of case reports. Thus this case report has not been submitted to the approbation of our regional ethical committee. Instead, this study has been ethically validated and authorized by the commission for clinical research of the Neuchâtel hospital network (institutional ethics committee), who approved the validity of this case report regarding good ehical and clinical practice, respectively regarding the Declaration of Helsinki (2023) and the ICH-GCP.

Credit author statement

Jérémie Gozzo: Bibliography, wrote the article, correction, reference layout, submission, Joao Gonçalves Nogueira: English translation, Stavros Georgopoulos: Correction and arrangement of the different parts, English correction, Jaroslaw Czekaj: Bibliography, lead the project, operated the patient, took the pictures, retrieved laboratory and pathology data, proofreading.

Funding statement

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.