Purpose: The gold standard for treatment of infected total hip or knee replacements remains a 2-stage exchange arthroplasty. This includes aggressive irrigation and debridement, implant removal, insertion of antibiotic impregnated spacers, iv antibiotics, and eventual reimplantion with a definitive prosthesis. The purpose of this study was to quantify Vancomycin and Gentamycin synovial fluid levels at the time of reimplantation following a 2-stage exchange arthroplasty for a infected total hip or knee replacements.

Methods: The senior author performed 42 two-stage reconstructions using the prosthesis of antibiotic-loaded acrylic cement (PROSTALAC). Each 40g bag of Pala-cos-R cement was impregnated with Vancomycin 2g, Gentamycin 4.8g, and plus/minus ancef 2.0g (depending on penicillin allergy). At the time of reimplantation, the synovial fluid was immediately analyzed for levels of Vancomycin and Gentamycin.

Results: 17 patients were taken for stage II within 60 days (avg. 53). The synovial fluid vancomycin and gentamycin levels were 12.7 and 20.6 respectively. Twelve patients had stage II between 60 and 90 days (avg. 79). The synovial fluid vancomycin and gentamycin levels were 6.2 and 14.9 respectively. The remaining 13 patients underwent stage II beyond 90 days (avg. 192), and their synovial fluid vancomycin and gentamycin levels were 3.3 and 2.4 respectively. 40 of 42 patients had their infections eradicated.

Conclusions: in vitro evidence predicts that antibiotics elute rapidly from bone cement. The results of this study confirm that substantial doses of vancomycin, gentamycin, and ancef per bag of Palacos-R cement does confer long term synovial fluid antibiotic levels well above the minimal inhibitory concentrations required to treat infected total joints. When stage II reimplantation is done at greater than 3 months, synovial fluid antibiotic levels decline significantly.

The influence of advancements in imaging and chemotherapy on patient with dedifferentiated chondrosarcoma was determined. There were forty-two cases in which twenty-seven patients received adjuvant therapy. Median survival was eight months and five-year survival was 4.8%. There was no statistical difference (p=0.62) in survival between patients who did and did not receive chemotherapy, had wide versus radical resection, or had limb sparing versus sacrificing procedures. There were no statistically significant differences between patients treated prior to 1986 and those subsequently. Despite advances, dedifferentiated chondrosarcoma continues to carry a poor prognosis. The routine adjuvant chemotherapy in this population should be questioned

The long-term survival for patients that presented with dedifferentiated chondrosarcoma has historically been poor. A large clinical series has not been analyzed in the era of modern diagnostic and treatment modalities. The current study was performed to look at the influence of advancements in imaging and chemotherapy on patient outcome. A retrospective chart review of all cases of patients presenting with dedifferentiated chondrosarcoma at our institution from 1984–2000 was performed. This was done as an extension to a study published in 1986 prior to the era of modern chemotherapy.

There were forty-two cases in twenty-five men and seventeen women of average age fifty-six (range twenty-four-eighty-three years). MSTS grades at presentation were IIA(5), IIB(27), and III(10). Three patients underwent biopsy only, nineteen had limb sacrificing surgery, and twenty had limb sparing procedures. Surgical margins were intralesional in three, marginal in two, wide in twenty, and radical in fourteen. Twenty-seven patients received adjuvant therapy (twenty-two chemotherapy only, two radiotherapy only, three combined therapy). Median survival was eight months and five-year survival was 4.8%. There was no statistical difference (p=0.62) in survival between patients who did and did not receive chemotherapy, had wide versus radical resection, or had limb sparing versus sacrificing procedures. There were no statistically significant differences between patients treated prior to 1986 and those subsequently.

Despite advances in diagnostic modalities, surgical treatments, and adjuvant therapies, dedifferentiated chondrosarcoma continues to carry a poor prognosis. The routine use of current adjuvant chemotherapy and its inherent risks and benefits in this population should be questioned.