Radiation-induced Skin Necrosis Following Intra-articular Yttrium-90 Hydroxyapatite in a Patient with Chronic Knee Synovitis

INTRODUCTION

In drug-resistant inflammatory arthritis, radionuclide synovectomy (RSV) with Yttrium-90 hydroxyapatite proved to be a safe and effective treatment for improving joint functionality.^[1] Cutaneous radiation necrosis is a rare complication of synovectomy, likely caused by para-articular injection of radiocolloid. The reason for tissue necrosis can be due to radionuclide applied outside the joint or reflux from the joint, joint infection, and issues arising from immobilization or improper technique.^[2] This uncommon issue should be suspected if an ulcer appears near a joint days or even months aft er a radiation synovectomy. Incidence of skin necrosis is 2:11,000 treatments. Diagnosing this condition can be difficult for rheumatologists, orthopedists, and dermatologists, particularly when skin lesions develop late. Recognizing this adverse effect is crucial for establishing an appropriate treatment plan and avoiding unnecessary procedures. Surgical excision is generally considered the best treatment.^[3-6]

We reported one case of radiation-induced skin necrosis (RISN) in a patient with nonspecific chronic inflammatory synovitis following intra-articular injection of Yttrium-90 and who was treated timely with topical medications. The occurrence of this kind of necrosis might affect the quality of life of patients.

CASE REPORT

A 40-year-old female visited department of orthopedics with complaints of right knee pain, recurrent swelling, difficulty in walking for the past 5 years and she was on analgesics like Indomethacin from many years, had recurrent synovial effusion and she was aspirated for synovial fluid five times in the last 1 year, magnetic resonance imaging report showed moderate joint effusion and was diagnosed as nonspecific chronic synovitis with recurrent effusion of the right knee. The patient had no known hypersensitivity to drugs and had not undergone any surgery for arthritis. At baseline, the patient was suffering from moderate joint restriction, severe pain (8/10) on Visual Analog Scale.

Aft er obtaining informed consent from the patient, three-phase bone scintigraphy was performed using Technetium 99m-methylene diphosphonate (Tc99 m-MDP). Triple phase bone scintigraphy was performed with 20 mCi of Tc99 m-MDP, which revealed increased flow and blood pool activity localizing to the right knee region, with the delayed phase showing increased tracer uptake in the right knee. The patient was diagnosed with mild inflammatory arthritis of the right knee and was found eligible to receive RSV.

The patient was planned for the RSV using Yttrium-90 hydroxyapatite. With the patient’s consent under aseptic conditions, intra-articular injection of 10 mCi Yttrium-90 hydroxyapatite was administered along with 10 mg triamcinolone injection as per standardized protocol in the department of nuclear medicine by a specialist under antibiotic cover. Images of the treated joint were acquired aft er the procedure using positron emission tomography-computed tomography to see the distribution of the radionuclide [Figure 1a and b].

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Figure 1:

(a) Maximum intensity projection (MIP) image showing Yttrium-90 Hydroxyapatite distribution in the right knee joint (b) positron emission tomography-computed tomography image of right knee joint: showing Yttrium-90 hydroxyapatite uptake

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The posttherapy scan revealed the distribution of the radionuclide (Y90) within the right knee joint. The patient was then advised to rest the treated right knee joint using a knee brace for a period of 48 h. The patient was discharged and advised to follow-up aft er 2 months. Patient noted an ulcer on the injected site, and the ulcer progressed in size. The patient came for a follow-up aft er 1 month. On examination, the patient was found to have superficial skin necrosis with sloughing of the dermis and was diagnosed with RISN [Figure 2]. The patient was advised to apply ointment mupirocin and placenta extract (PE) to the affected area. The patient was followed up aft er 2 months and the ulcer was found to be healing, moderate joint restriction with severe pain (8/10), and thepatient continued the same medications and was advised to take an analgesic when needed. After 6 months, the lesion was healed with no break in the skin, mild joint restriction, mild pain (3/10), and patient complaints of itching at the lesion site, which might be accounted for by the healing process and were dealt with a topical antihistamine.

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Figure 2:

Right knee joint of the study patient: Acute adverse reaction (radiation-induced skin necrosis) aft er radionuclide synovectomy (RSV). (a) Right knee showing swelling before receiving RSV (b) Aft er 7 days-Necrosed tissue at the injected site-anterolateral of right knee (c) Aft er 14 days- pus discharge through a track from the base of the ulcer (d) Aft er 1 month-scab formation with necrosed tissue (e) Aft er 2 months the ulcer healed (f) Aft er 6 months-healed ulcer

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DISCUSSION

Skin necrosis is a rare complication aft er intra-articular Yttrium-90, which has to be identified at the earliest.^[4] Intra-articular radionuclides should be administered by an experienced physician/surgeon. If skin necrosis develops, flap surgery or hyperbaric oxygen therapy (HBOT) is among the preferred options as per existing literature.^[7,8] HBOT is a commonly used adjunctive treatment for radiation tissue injury.^[2,9] It involves breathing 100% oxygen at pressures >1 atmosphere absolute in an airtight chamber. Although the precise mechanism of action of HBO in irradiated tissue is not fully understood, it is believed that the increase in local oxygen tension promotes angiogenesis, collagen formation, and antimicrobial defense.^[10]

Human PE has been utilized for wound healing in Chinese folk medicine. Its medical and dermatological benefits have been documented, with recent reports highlighting its positive effects on chronic and nonhealing wounds.^[11] They have shown significant positive effects in treating wounds, nonhealing ulcers, and burns, by increasing the rate of epithelialization and decreasing infiltration and pain.^[12,13] It is also a component of various skin ointments, used for skin revitalization, nourishment, melanocyte growth, pigment-inducing activities, and for treating skin hypersensitivity conditions such as dermatitis and psoriasis.^[14,15] Rosenthal studied extract from human placenta in rheumatic arthritis by using iontophoresis to administer Placenta Lucchini along with catalase and mucopolysaccharidase for acute rheumatic inflammation leads to notable clinical improvement, which is not observed when placenta is used on its own.^[14] Even though human PE is not an established option, it showed a beneficial effect in this patient.

The chances of graft rejection are higher with skin graft ing and flap surgery, and patients must be on immunosuppressants. It is a surgical procedure; patients must stay in the hospital for a few days, which might be costly and affect the quality of life of the patient. HBOT is available in very few places. PE can be tried in RISN patients if noticed at the earliest, might be cost-effective, and improve the quality of life of the patient.

The reason for tissue necrosis might be inappropriate radionuclide administration or leakage and extra-articular deposition of the radionuclide in the joint. To reduce the risk of leakage, cotton swabs should be changed aft er compressing the injection site. Identifying and treating this condition the earliest might avoid other procedures like skin graft ing.

CONCLUSION

Proper intra-articular radionuclide administration by a skilled physician under aseptic conditions is vital. Prompt recognition of RISN is important, and human PE may serve as an effective conservative treatment to enhance quality of life. While the efficacy of placental extract is not yet unequivocally established, its potential benefit in such rare scenarios, as observed in our case, warrants further exploration and discussion.