Abstract
Introduction Maquet views are a well established method of determining the axial alignment of the lower limb in the coronal plane and their use in the assessment of total knee replacement is widespread. It is an awkward investigation for both patient and radiographer and we compared them to the information that can be obtained using the new generation of Helical CT scanners.
Results We prospectively studied a cohort of 60 patents undergoing TKR. As part of their routine post-operative follow-up they had a standard series of AP and Lateral radiographs (performed under fluoroscopic control) in addition to the Maquet views and a CT scan of their lower limbs. All plain films were performed at the same hospital by the same group of radiographers, while all CTs were performed on the same scanner using a predetermined protocol, and post processing performed by the same individual. Maquet views gave a good assessment of coronal alignment but were also shown to have a much high interobserver error than CT. Maquet views took on average three times longer for the radiographers to perform than CT, were often repeated as technically demanding, and patients (especially the elderly and infirm) often found it difficult and uncomfortable to comply with the required positioning. CT views on each patient (which incorporated standard slices and a scanogram) took a few minutes of time in the scanner allowing a quick throughput when patients arrived in clinic. Patients were supine, a position they all found easy to adopt, and radiographers reported that they found them less difficult to perform. The femoral and tibial axes were easily determined, and rotation easily assessed from the femoral epicondyles, negating the projection errors due to malrotation that may compromise the accuracy of Maquet views. Radiation dosage for the CT is higher than a single Maquet view, but these are often repeated due to poor exposure, increasing the dosage above that of CT.
Conclusions We have used a spiral CT protocol with much success and feel that its greater accuracy, coupled with the information gained on sagittal alignment and component rotation means that the older Maquet view has now been superceded. We also feel that the amount of information recorded by a single investigation may prove invaluable in subsequent investigation of pain or suspected loosening, and very helpful in planning any required revision.
The abstracts were prepared by Mr Jerzy Sikorski. Correspondence should be addressed to him at the Australian Orthopaedic Association, Ground Floor, William Bland Centre, 229 Macquarie Street, Sydney NSW 2000, Australia.
None of the authors have received any payment or consideration from any source for the conduct of this study.
