Recurrent Hemarthrosis Secondary to Erosive Patellofemoral Arthritis Treated with Arthroplasty: A Report of 3 Cases.

CASE: Three patients presented with recurrent hemarthrosis secondary to erosive patellofemoral arthritis. Recurrent hemarthrosis from the eroded patellofemoral subchondral bone has not been well described. Each patient presented with symptoms secondary to painful effusions that were identified by aspiration. Each patient was successfully treated with patellofemoral or total knee arthroplasty. CONCLUSION: Spontaneous or recurrent effusions in the setting of erosive patellofemoral arthritis should prompt orthopaedic surgeons to consider hemarthrosis as the cause of such effusions. Patellofemoral or total knee arthroplasty is effective in resolving the hemarthroses, resolving pain, and restoring function in these patients.

Giardia lamblia Reactive Arthritis Mimicking Acute Periprosthetic Knee Infection: A Case Report.

CASE: A healthy 49-year-old man with a well-functioning total knee replacement developed a painful swollen knee. The erythrocyte sedimentation rate was 12 mm/hour, and C-reactive protein was 20.3 mg/L. Aspiration revealed 24,440 white blood cells and 5% neutrophils. His 2018 International Consensus Meeting (ICM) definition score of 5 met criteria for "possibly infected." He was diagnosed with reactive arthritis (ReA) secondary to Giardia lamblia, mimicking acute periprosthetic infection. He was successfully treated with a 10-week course of multiple oral antiparasitic medications. CONCLUSION: Systemic parasitic infectious ReA can mimic acute infection in the presence of total knee arthroplasty. Careful application of the 2018 ICM criteria can be critical for workup and the treatment of suspected periprosthetic infection.

Subtrochanteric femur fracture after core decompression and placement of a tantalum strut for osteonecrosis of the femoral head.

Multiple treatment options have been described to treat osteonecrosis of the femoral head, all with the goal of slowing or reversing the disease process and preventing the need for arthroplasty in a young patient population. Core decompression of the femoral head to allow revascularization is a commonly used technique that can now be supplemented by placement of the Osteonecrosis Intervention Implant (Zimmer, Warsaw, Ind). It consists of a tantalum strut that acts as a buttress for the subchondral bone of the femoral head. In this case, our patient underwent this procedure with subsequent subtrochanteric fracture. The factors leading to this iatrogenic injury are location of implant insertion, patient selection, and premature ambulation.