There are several imaging-based measurements for patello-femoral height. Available methods rely predominantly on sagittal images. The latter can be misleading with sagittal oblique slices and when the patella is tilted and/or chronically subluxed. In this study we describe a simple method of patellar height measurement using axial MRI overlap. A retrospective observational analysis of 97 knees from 251 patients was conducted. Cases were selected following the exclusion of scans with fractures, massive effusion, patello-femoral pathology. Axial patello-trochlear overlap (APTO) was measured on the axial MRI images as follows: (1) Patellar length (P): expressed as the number of axial images showing patellar articular surface (2) Trochlear overlap (T): the number of axial images showing overlap between patellar articular surface and articular surface of lateral trochlea. APTO is the ratio T/P. All measurements were carried out independently and on two separate occasions by 6 raters. As a control conventional patello-trochlear index were measured for all patients by a senior musculoskeletal radiologist.Abstract
Introduction
Materials and methods
To assess the radiological outcome of instrumented posterolateral lumbar fusion in a prospective randomised study comparing the use of allograft (fresh frozen human femoral head) to autologous bone (from the posterior iliac crest), using a validated method. One hundred and twenty four radiographs of patients who had undergone instrumented posterolateral spinal fusion were assessed for fusion or non-fusion by three independent observers using the same criteria, and a second time by one of the observers. The Kappa scores for the inter-observer and intra-observer agreement were calculated. Thirty-three of these patients had fusion status verified by the gold randomised to one of two groups, to receive either allograft bone or autologous bone. The same surgeon using the same surgical technique performed or supervised all cases. The radiological results of the two groups were assessed as well as the quality of fusion. Both the inter-observer and intra-observer kappa scores (k) were 100%. The sensitivity of the method was 87.9% and the specificity was 100%. Thirty-seven patients received allograft and 32 patients received autograft. There was no significant difference in the fusion rate, or the quality and quantity of the graft between the groups. There is no difference in the fusion rates comparing the use of autograft and allograft for posterolateral instrumented lumbar fusion.
