We evaluated the accuracy of augmented reality (AR)-based navigation assistance through simulation of bone tumours in a pig femur model. We developed an AR-based navigation system for bone tumour resection, which could be used on a tablet PC. To simulate a bone tumour in the pig femur, a cortical window was made in the diaphysis and bone cement was inserted. A total of 133 pig femurs were used and tumour resection was simulated with AR-assisted resection (164 resection in 82 femurs, half by an orthropaedic oncology expert and half by an orthopaedic resident) and resection with the conventional method (82 resection in 41 femurs). In the conventional group, resection was performed after measuring the distance from the edge of the condyle to the expected resection margin with a ruler as per routine clinical practice.Objectives
Methods
We hypothesised that the synovial white blood cell (WBC) count
in patients with a late periprosthetic joint infection (PJI) of
the hip would depend on the duration of a patient’s symptoms, and
that the optimal diagnostic threshold would also depend on this
period of time. The synovial WBC count and percentage of polymorphonuclear cells
(%PMN), and the serum CRP and ESR levels obtained >
six weeks after
primary THA were compared between 50 infected and 88 non-infected
THAs, and in patients with symptoms for more than or less than two
weeks. Diagnostic thresholds for the synovial WBC count were calculated
using area under the curve calculation.Aims
Patients and Methods
Lengthening of the humerus is now an established
technique. We compared the complications of humeral lengthening
with those of femoral lengthening and investigated whether or not
the callus formation in the humerus proceeds at a higher rate than
that in the femur. A total of 24 humeral and 24 femoral lengthenings
were performed on 12 patients with achondroplasia. We measured the
pixel value ratio (PVR) of the lengthened area on radiographs and
each radiograph was analysed for the shape, type and density of
the callus. The quality of life (QOL) of the patients after humeral
lengthening was compared with that prior to surgery. The complication
rate per segment of humerus and femur was 0.87% and 1.37%, respectively.
In the humerus the PVR was significantly higher than that of the
femur. Lower limbs were associated with an increased incidence of
concave, lateral and central callus shapes. Humeral lengthening
had a lower complication rate than lower-limb lengthening, and QOL
increased significantly after humeral lengthening. Callus formation
in the humerus during the distraction period proceeded at a significantly
higher rate than that in the femur. These findings indicate that humeral lengthening has an important
role in the management of patients with achondroplasia.
