Elevated cobalt levels in metal-on-polyethylene knee megaprostheses: a prospective 1-year cohort study of 56 patients with hip and knee megaprostheses.

BACKGROUND AND PURPOSE: Concerns have emerged regarding elevated levels of cobalt and chromium in patients with metal-on-metal megaprostheses. This prospective study aims to identify systemic cobalt and chromium levels in metal-on-polyethylene knee and hip megaprostheses and their associations with other factors. METHODS: 56 patients underwent knee or hip megaprosthesis surgery at 2 sarcoma centers. Serum cobalt and chromium levels were measured preoperatively and thrice within the first year using inductively coupled plasma mass spectrometry. RESULTS: A statistically significant difference in serum cobalt levels (1.4 ppb; 95% confidence interval [CI] 0.0-3.3) was observed 1 year after knee megaprosthesis surgery compared with preoperative levels. In contrast no difference in chromium levels was observed after 1 year compared with preoperative levels (0.05 ppb; CI 0.0-0.8). An association between younger age, higher eGFR, and increased cobalt levels was observed. No significant correlations were found between ion levels and resection length or the number of modular connections. CONCLUSION: We found elevated serum ion levels in metal-on-polyethylene knee megaprostheses in contrast to metal-on-polyethylene hip megaprostheses. Furthermore, a positive correlation between cobalt and chromium levels, and between cobalt and eGFR was identified, along with a negative correlation between cobalt and age. This study highlights the importance of monitoring systemic cobalt and chromium levels in patients with megaprostheses.

[Purtscher's retinopathy as a complication to a cemented resection tumour prosthesis].

In this case report, a 53-year-old female with a pathological subtrochanteric femur fracture received a cemented resection tumour prosthesis. The patient was post-operatively diagnosed with Purtscher's retinopathy due to fat embolisation. Purtscher's retinopathy has previously been described in trauma patients, however, no previous reports exist with patients treated with prosthesis. No treatment guideline is available. There is a risk of permanent visual impairment, and it is recommended, that patients presenting reduced vision post-operatively are referred to an ophthalmologist without delay for correct diagnosis.

Is there consensus regarding surgical treatment of bone sarcomas?

AIM: To perform an Internet based survey on the surgical management of bone sarcomas in the lower extremity amongst sarcoma surgeons. METHODS: All orthopedic surgical members of the Scandinavian Sarcoma Group were invited to participate in an online questionnaire. The questionnaire consisted of a clinical case involving resection of a malignant bone tumor. Several questions were asked, subdivided into categories. Among these, surgical/technical considerations, e.g., choice of implant; choice of antibiotics, dosage, and duration of treatment, choice of antithrombotic drug, initial start-up, dosage, and duration were included. RESULTS: In terms of choice of implant fixation, the majority of surgeons preferred an uncemented prosthesis in younger patients until the age of 50. All participants administer intravenous prophylactic antibiotics for endoprosthetic reconstructive surgery. First choice of antibiotics was cephalosporin. Less common used was glycopeptide, penicillin, or a combination. Duration of prophylactic antibiotics ranged from less than one day to more than four days. All participants used low molecular weight heparins as antithrombotic prophylaxis and 55% of the participants answered that initial treatment was started preoperatively, 3% perioperatively and 42% postoperatively. Duration of the antithrombotic treatment ranged from five days to more than twenty-eight days. CONCLUSION: The use of resection prosthesis in the treatment of bone sarcomas is a well-established procedure. However, therse is a significant discrepancy in the surgical treatment algorithm between the sarcoma centers. Still the treatment is mainly based on best clinical practice, due to the lack of evidence-based medicine in the surgical management of bone sarcomas.