Early outcomes and radiographic alignment of the Infinity total ankle replacement with a minimum of two year follow-up data.

BACKGROUND: The Infinity total ankle replacement (Wright Medical Technology, Memphis, TN) is a low profile, fluoroscopically navigated, fixed-bearing device. We hypothesised that the fluoroscopic navigation would allow more accurate alignment of the prosthesis than conventional techniques. We present our minimum two year follow up data of Infinity ankle replacements. METHODS: All total ankle replacements (TARs) performed at our institution were prospectively followed-up with EQ5-D and MOx-FQ scores as well as intra-operative radiation exposure and radiographic alignment data. Post-operative radiographs were used to measure the alignment of the prostheses. We identified 20 implants with minimum of two year follow up which were compared to a control group of 20 Zenith TAR's (Corin, Cirencester, UK). RESULTS: Intra-operative fluoroscopic navigation has allowed excellent alignment of all prostheses. Median deviations from 90° alignment to the anatomical axis of the tibia were 1.5° and 1.2° in the anterior-posterior (AP) and lateral planes respectively, compared to 2.8° and 3.1° in the Zenith group. This difference reached significance (p=<0.05) using the Mann-Whitney U test. At 2 years, MOx-FQ scores had fallen from pre-operative mean of 63.9∓17.1 to 15∓12.7. EQ-5D VAS scores had improved from 71.3∓17.3 to 81.4∓9.7 points. Radiation exposure had a mean screening time of 82∓29.4s and a decrease in exposure per patient was observed over time. No patients have undergone, or are awaiting, revision surgery. Complications include one intraoperative medial malleolar tip avulsion fracture, one medial malleolar stress fracture, and one patient who developed CRPS. CONCLUSIONS: We present evidence that this system achieves better anatomical alignment of the components when compared to techniques without fluoroscopic navigation. The implant survival and complication profile at a minimum of two years is satisfactory.

Low-grade malignant Triton tumor of the oral cavity: a case report.

Malignant Triton tumor (MTT) is a malignant peripheral nerve sheath tumor showing rhabdomyoblastic differentiation. It is considered a high-grade neoplasm with poor outcome. This report describes an MTT appearing in the oral cavity. On histologic examination the encapsulated lesion was composed of interlacing fascicles of spindle cells and scattered, large, strap-like pleomorphic cells with abundant eosinophilic cytoplasm. No cross striations were seen. Examination of levels through the tissue showed a total of only 4 normal mitoses and no necrosis. Immunohistochemistry demonstrated diffuse S100 positivity in the spindle cells. The large pleomorphic cells were weakly positive for alpha-sarcomeric actin and myoglobin, although variably but strongly positive for desmin. Management involved a small en bloc resection of the maxilla. After 33 months there was no sign of recurrence or distant metastasis. It was concluded that low-grade variants of MTT occur that do not have an aggressive clinical course.