Little is known about patients that undergo presumed aseptic revision arthroplasty surgery of the hip and knee joint and having positive microbiological findings of the intraoperatively taken tissue samples. 228 “aseptic” operations were retrospectively analyzed from prospectively collected data with regard to the following parameters: demographic data; reasons for primary and revision surgery, respectively; time between primary and revision surgery; preoperative laboratory findings; microbiological and histopathological findings; type and length of systemic antibiotic therapy; clinical outcome; and follow-up. Identification of microorganisms was present in 8.8% of the cases (9.3% of the hip and 7.8% of the knee cases). Preoperatively, the median CRP value was 8.4 mg/l (normal values 0-5.0 mg/l) and the median WBC count 8,100×106/l (normal values 3,700‐10,100×106/l). The most common identified organism was methicillin-resistant Staphylococcus epidermidis in 30%, followed by viridans streptococci in 15% of the cases. In 7 cases, the microbiological findings were interpreted as a contamination, and no antibiotic therapy was administered. In the other cases, a systemic antibiotic therapy was applied for a time period between 2 weeks and 3 months. 68.4% of the patients did not have any infectious complications at a median follow-up of 20 (3-42) months. The present study indicates that more than 2/3 of the cases with positive microbiological findings at the site of presumed aseptic revision arthroplasty surgery of the hip and knee joint can be successfully treated conservatively and they do not require any further surgical therapy.

Significance: Negative pressure wound therapy (NPWT) has become a valuable adjunct in the treatment of acute and chronic wounds in several surgical disciplines. Retained foams are among its side effects, and they pose a rare but devastating complication at the site of this therapy, which might be associated with wound-healing complications, infection persistence, repeated surgical revisions, and prolonged antibiotic courses. Recent Advances: In the past 15 years, an increasing number of studies have identified this potential problem. Although the exact incidence remains unknown, initial studies have indicated rates of up to 10% in large collectives being treated by NPWT. Critical Issues: The lack of radiopaque markers does not allow for the visual control of retained foams using plain radiographs. Further imaging methods (e.g., CT and MRI) also do not help in adequate differential diagnosis. The lack of routine documentation of the number, type, and localization of the inserted foam(s) and unplanned surgery with a different surgical team pose risk factors for foam retainment. Future Directions: Introducing new documentation records for wounds treated with NPWT is recommended. At foam removal, all dressing materials should be examined for integrity. The development of foams with radiopaque markers by the industry, such as those routinely used in surgical gauze swabs, might also be a useful step to minimize the risk of foam retainment within wounds.

A 48-year-old male patient presented in our department with knee osteoarthritis and a giant cystic lesion of the lateral femoral condyle. Bone biopsy of the lesion was performed. Histopathological examination confirmed the presence of a solitary bone cyst. The patient was treated by curettage of the cyst, filling with a synthetic resorbable bone graft substitute (Cerament™), and primary, cruciate-retaining total knee arthroplasty. 4 months after surgery, complete osseointegration of the bone graft substitute was evident on X-rays. The use of modern bone graft substitutes might be a novel alternative to other established techniques in the management of large bone lesions, even at the site of primary total knee replacement.

Periprosthetic infections are hazardous complications. After dental procedures, an antibiotic prophylaxis or treatment is actually not recommended according to the current guidelines. In the present work, a case of a hematogenous late infection after primary total hip arthroplasty due to a prior dental procedure is presented. Hereby, the question evolves as to whether in selected cases an antibiotic prophylaxis or treatment might be indicated at the site of dental procedures.

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