Knee pain; Knee replacement; Postoperative pain/Had knee replacement and in lots of pain; Post procedural swelling/Post surgical swelling; Could not think straight; This spontaneous case was reported by a consumer and describes the occurrence of ARTHRALGIA (Knee pain) and KNEE ARTHROPLASTY (Knee replacement) in a 67-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product ADALIMUMAB (HUMIRA) for Rheumatoid arthritis.    The patient's past medical history included Colonoscopy (Everything good) in 2022. Concurrent medical conditions included Tobacco user (Half to one pack per day) since July 2022, Obesity (The patient's BMI is 32.1) and Rheumatoid arthritis. Concomitant products included GOLIMUMAB (SIMPONI ARIA) for Rheumatoid arthritis, OMEPRAZOLE for an unknown indication.   In 2012, the patient started ADALIMUMAB (HUMIRA) (Subcutaneous) 40 milligram. On 27-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 27-May-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 10-Nov-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. In 2022, the patient experienced KNEE ARTHROPLASTY (Knee replacement) (seriousness criterion medically significant), PROCEDURAL PAIN (Postoperative pain/Had knee replacement and in lots of pain), POST PROCEDURAL SWELLING (Post procedural swelling/Post surgical swelling) and THINKING ABNORMAL (Could not think straight). On an unknown date, the patient experienced ARTHRALGIA (Knee pain) (seriousness criterion medically significant). The patient was treated with FAMOTIDINE, IBUPROFEN (DUEXIS) at an unspecified dose and frequency and IBUPROFEN (ADVIL [IBUPROFEN]) at an unspecified dose and frequency. At the time of the report, ARTHRALGIA (Knee pain) and KNEE ARTHROPLASTY (Knee replacement) was resolving, PROCEDURAL PAIN (Postoperative pain/Had knee replacement and in lots of pain) outcome was unknown and POST PROCEDURAL SWELLING (Post procedural swelling/Post surgical swelling) and THINKING ABNORMAL (Could not think straight) had not resolved.            Patient was non-alcohol user. It was unknown if patient was enrolled in a COVID-19 Vaccine Trial. Patient had been getting jell shots in her knee for the pain. For HUMIRA, reporter causality was reported as not related for post procedural swelling and thinking abnormal, not reported for postprocedural pain and no reasonable possibility for knee pain. Agency causality reported as no reasonable possibility for all events.  Company Comment: This is a spontaneous case concerning a 67-year-old, female patient with relevant concurrent medical conditions of rheumatoid arthritis and obesity (BMI: 32.1). Patient has co-suspect medication of Adalimumab (Humira) for rheumatoid arthritis. Patient experienced the unexpected serious (medically significant) events of knee pain and knee arthroplasty, and the unexpected non-serious events of procedure pain (postoperative pain/had knee replacement and in lots of pain), post procedural swelling, and thinking abnormal (could not think straight). On 27th April, 27th May and 10th November in the year 2021, patient received first, second and third dose of mRNA-1273 vaccine respectively. On unknown date, patient experienced knee pain. On unknown day and month in the year 2022, patient underwent knee arthroplasty and experienced procedure pain and post procedural swelling. Thinking abnormal (could not think straight) was also reported on unknown day and month in the year 2022. No further clinical information was available for medical review. The concurrent medical conditions of rheumatoid arthritis and obesity (BMI: 32.1) remain confounders for the event knee pain. The concurrent medical conditions of rheumatoid arthritis and obesity, and the event knee pain remain confounders for the event knee arthroplasty. The surgical procedure of knee arthroplasty remain confounder for the events procedure pain and post procedural swelling. The co-suspect medication of Adalimumab (Humira) remain confounder for the event knee pain. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.; Sender's Comments: This is a spontaneous case concerning a 67-year-old, female patient with relevant concurrent medical conditions of rheumatoid arthritis and obesity (BMI: 32.1). Patient has co-suspect medication of Adalimumab (Humira) for rheumatoid arthritis. Patient experienced the unexpected serious (medically significant) events of knee pain and knee arthroplasty, and the unexpected non-serious events of procedure pain (postoperative pain/had knee replacement and in lots of pain), post procedural swelling, and thinking abnormal (could not think straight). On 27th April, 27th May and 10th November in the year 2021, patient received first, second and third dose of mRNA-1273 vaccine respectively. On unknown date, patient experienced knee pain. On unknown day and month in the year 2022, patient underwent knee arthroplasty and experienced procedure pain and post procedural swelling. Thinking abnormal (could not think straight) was also reported on unknown day and month in the year 2022. No further clinical information was available for medical review. The concurrent medical conditions of rheumatoid arthritis and obesity (BMI: 32.1) remain confounders for the event knee pain. The concurrent medical conditions of rheumatoid arthritis and obesity, and the event knee pain remain confounders for the event knee arthroplasty. The surgical procedure of knee arthroplasty remain confounder for the events procedure pain and post procedural swelling. The co-suspect medication of Adalimumab (Humira) remain confounder for the event knee pain. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.