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Risk of reoperation, deep infection increased in patients who return early for evacuation of postoperative hematoma after total knee arthroplasty

Thursday, November 13 2008 | Comments

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What's This? Patients returning to the operating room within 30 days of total knee arthroplasty (TKA) for evacuation of a postoperative hematoma have a significantly increased risk of developing a deep infection and/or undergoing subsequent major surgery, according to recent data.

To evaluate the clinical outcomes in patients who require surgical evacuation of an acute hematoma, investigators recorded 17,784 primary TKAs performed at the Mayo Clinic. Overall, 42 patients (42 knees) returned to the operating room within 30 days of the TKA for evacuation of a postoperative hematoma.

To estimate the incidence and long-term sequelae of hematoma formation requiring surgical evacuation, those 42 knees were compared to the 17,742 remaining knees that did not have a hematoma less than 30 days after TKA. Researchers measured 2 endpoints in the groups: 1) any major surgery following the initial evacuation and 2) the development of a deep infection below the fascia. Both endpoints were defined as occurring more than 30 days after TKA.

Overall, the rate of return to surgery within 30 days for evacuation of a postoperative hematoma in this series was 0.24% (95% CI, 0.17%-0.32%). Five of the 42 patients (11.9%; 95% CI, 4.0%-25.6%) with surgical treatment of a postoperative hematoma eventually underwent subsequent major surgery as compared with 200 of the 17,742 (1.1%; 95% CI, 1.0%-1.3%) who did not have a hematoma. Furthermore, 5 patients (11.9%; 95% CI, 4.0%-25.6%)  in the hematoma group developed a deep infection versus 324 (1.8%; 95% CI, 1.6%-2.0%) in the non-hematoma group.

For patients who underwent postoperative hematoma evacuation, the 2-year cumulative probabilities of undergoing subsequent major surgery (component resection, muscle flap coverage, or amputation) or developing a deep infection were 12.3% (95% CI, 1.6%-22.4%) and 10.5% (95% CI, 0.2%-20.2%), respectively. For knees that did not have early hematoma evacuation, the 2-year cumulative probabilities were 0.6% (95% CI, 0.5%-0.7%) and 0.8% (95% CI, 0.6%-0.9%), respectively (P<.001 for both outcomes).

The researchers also conducted a retrospective, matched case-control study to identify risk factors for the development of postoperative hematoma requiring surgical evacuation. Based on age and sex, they matched the 42 patients with a hematoma requiring evacuation to 42 controls who had a primary TKA but did not have a hematoma requiring surgical intervention within 30 days.

A history of a bleeding disorder was significantly associated with the development of a hematoma requiring reoperation within 30 days (OR, >100; 95% CI, 1.6 to infinity; P=.046).

"[W]hile the rate of major hematoma formation requiring surgical treatment is low after primary TKA, the associated morbidities are substantial, and, therefore, avoidance of this problem should be a priority," the researchers concluded. "Postoperative anticoagulation should be monitored carefully in all patients, especially those who require postoperative heparin treatment. Furthermore, monitoring and treatment of patients with known bleeding disorders should be emphasized." (Galat D, et al. J Am Bone Joint Surg Am 2008;90:2331-2336.)

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