Recently, several synovial biomarkers have been introduced into
the algorithm for the diagnosis of a prosthetic joint infection
(PJI). Alpha defensin is a promising biomarker, with a high sensitivity
and specificity, but it is expensive. Calprotectin is a protein
that is present in the cytoplasm of neutrophils, is released upon
neutrophil activation and exhibits anti-microbial activity. Our
aim, in this study, was to determine the diagnostic potential of
synovial calprotectin in the diagnosis of a PJI. In this pilot study, we prospectively collected synovial fluid
from the hip, knee, shoulder and elbow of 19 patients with a proven
PJI and from a control group of 42 patients who underwent revision
surgery without a PJI. PJI was diagnosed according to the current diagnostic criteria
of the Musculoskeletal Infection Society. Synovial fluid was centrifuged
and the supernatant was used to measure the level of calprotectin
after applying a lateral flow immunoassay. Aims
Patients and Methods
We reviewed the outcome of 69 uncemented, custom-made,
distal femoral endoprosthetic replacements performed in 69 patients
between 1994 and 2006. There were 31 women and 38 men with a mean
age at implantation of 16.5 years (5 to 37). All procedures were
performed for primary malignant bone tumours of the distal femur.
At a mean follow-up of 124.2 months (4 to 212), 53 patients were
alive, with one patient lost to follow-up. All nine implants (13.0%)
were revised due to aseptic loosening at a mean of 52 months (8
to 91); three implants (4.3%) were revised due to fracture of the
shaft of the prosthesis and three patients (4.3%) had a peri-prosthetic
fracture. Bone remodelling associated with periosteal cortical thinning
adjacent to the uncemented intramedullary stem was seen in 24 patients
but this did not predispose to failure. All aseptically loose implants
in this series were diagnosed to be loose within the first five
years. The results from this study suggest that custom-made uncemented
distal femur replacements have a higher rate of aseptic loosening
compared to published results for this design when used with cemented
fixation. Loosening of uncemented replacements occurs early indicating
that initial fixation of the implant is crucial. Cite this article:
