Gout May Mimic Infection, Even Years After Achilles Tendon Repair.

BACKGROUND: Gout can affect tendons in addition to joints and may clinically resemble infection. The resulting diagnostic uncertainty may lead to surgical intervention or antibiotic treatment, even in patients whose symptoms might be managed medically if gout is recognized earlier.

QUESTIONS/PURPOSES: (1) Does late-onset gouty Achilles tendinopathy after prior Achilles tendon repair clinically resemble infection? (2) What diagnostic findings, including crystal analysis of aspirate or surgically obtained material when available, helped establish or support gout rather than infection? (3) What were the outcomes after gout was confirmed or suspected?

METHODS: This is a report of 4 patients with a similar presentation. Between April 2021 and June 2024, three surgeons at three academic medical centers identified 4 adult males, aged 42 to 55 years, who developed acute atraumatic Achilles-region pain, swelling, erythema, drainage, fluctuance, or induration 2 to 18 years after open Achilles tendon repair. These presentations raised concern that gout at or near a prior Achilles tendon repair site may mimic infection and lead to unnecessary interventions when gout is not considered early. We do not have an underlying denominator of patients treated for Achilles tendon repair by these surgeons during this period, but we speculate that it is on the order of several hundred. Minimum follow-up was 6 months after the treatment selected for the index Achilles inflammatory presentation. No patients who met these criteria were excluded, and no patients were lost to follow-up before the minimum follow-up interval. To determine whether this presentation clinically resembled infection, we reviewed presenting symptoms and physical examination findings, including pain, swelling, erythema, drainage, fluctuance, induration, fever, constitutional symptoms, and the treating surgeon's initial diagnostic concern. To answer our second question regarding diagnostic findings that established or supported gout rather than infection, we reviewed laboratory studies, imaging, aspiration findings, Gram stain, bacterial cultures, surgical findings, and pathologic evaluation for monosodium urate crystals. To answer our third question regarding outcomes, we reviewed whether patients underwent aspiration, surgical irrigation and debridement, antibiotics, immobilization, antiinflammatory or urate-lowering therapy, rheumatology or infectious disease referral, symptom resolution, recurrence, and complications. Three patients underwent aspiration and/or surgical irrigation and debridement for presumed infection. One patient was treated nonsurgically for suspected gout.

RESULTS: In 3 of 4 patients, late-onset gouty Achilles tendinopathy after prior Achilles tendon repair clinically resembled infection; it raised concern for an acute inflammatory or infectious process in all 4 patients. Among the 3 patients treated surgically, chalky tophaceous material was identified adjacent to the Achilles tendon, bacterial cultures were negative, and histological analysis confirmed monosodium urate crystals. The fourth patient had suspected gout based on hyperuricemia, Achilles-region symptoms, and improvement with nonsurgical treatment, although gout was not pathologically confirmed. All patients reported symptom resolution by latest follow-up (6 to 16 months).

CONCLUSION: Acute gouty tendinopathy can present years after Achilles tendon repair and can closely mimic postoperative infection, even when serum uric acid is normal. In patients without systemic signs of sepsis, earlier consideration of gout and routine crystal analysis when aspirate or surgically obtained material is available may help avoid unnecessary surgical debridement or prolonged empiric antibiotics when infection is not otherwise supported.

LEVEL OF EVIDENCE: Level IV, therapeutic study.