Article

Multimodality correlations of patellar height measurement on X-ray, CT, and MRI.

Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 601 North Caroline Street, JHOC 3262, Baltimore, MD 21287, USA.
Skeletal Radiology (Impact Factor: 1.74). 03/2012; 41(10):1309-14. DOI: 10.1007/s00256-012-1396-3
Source: PubMed

ABSTRACT To investigate whether the universally accepted range of normal patellar height ratios derived from radiography for the Insall-Salvati (IS) and Blackburne-Peel (BP) methods could be similarly applied to both CT and MRI.
Institutional review board approval was obtained with waiver of informed consent for this HIPPA-compliant study. A total of 45 knees in 42 patients (15 men, 27 women; age range 11 to 75 years, mean age 39 ± 20 years) who underwent tri-modality (radiograph, CT, and MRI) examinations were selected. All patients had knee imaging obtained for a variety of reasons and measurements were performed by two independent readers who were blinded to each other's measurements or the respective measurements derived from each of the methods. Paired t test was used to compare the mean values among the modalities. Inter-observer and inter-method agreements were assessed using intra-class correlation coefficients.
Statistically significant, but small quantitative differences are noted between tri-modality patellar height ratios. For comparable results, the small addition of 0.13 and 0.10 are needed for the Insall-Salvati measurements on MRI and CT respectively, compared with radiographs. For the Blackburne-Peel ratio, an additional adjustment of 0.09 is needed between radiographs and MRI, but not between radiographs and CT. These adjustments are independent of gender. The interobserver reproducibility was excellent (ICC ≥ 0.94) for both the Insall-Salvati and Blackburne-Peel methods for all modalities.
The results indicate that cut-off values for patella alta and baja derived from radiographs should not be directly transposed to CT and MRI; however, the adjustments are relatively minor. These measurements show excellent reproducibility for all modalities currently used for patellar height measurements.

1 Follower
 · 
821 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In total knee arthroplasty, surgical navigation systems provide tibio-femoral joint (TFJ) tracking for relevant bone preparation, disregarding the patello-femoral joint (PFJ). Therefore, the important intra-operative assessment of the effect of component positioning, including the patella, on the kinematics of these two joints is not available. The objective of this study is to explore in vivo whether accurate tracking of the patella can result in a more physiological TFJ and PFJ kinematics during surgery. Ten patients underwent navigated knee replacement with patellar resurfacing. A secondary system was used to track patellar motion and PFJ kinematics using a special tracker. Patellar resection plane position and orientation were recorded using an instrumented probe. During all surgical steps, PFJ kinematics was measured in addition to TFJ kinematics. Abnormal PFJ motion patterns were observed pre-operatively at the impaired knee. Patellar resection plane orientation on sagittal and transverse planes of 3.9° ± 9.0° and 0.4° ± 4.1° was found. A good restoration of both TFJ and PFJ kinematics was observed in all replaced knees after resurfacing, in particular the rotations in the three anatomical planes and medio-lateral patellar translation. Patella tracking results in nearly physiological TFJ and PFJ kinematics in navigated knee arthroplasty with resurfacing. The intra-operative availability also of PFJ kinematics can support the positioning not only of the patellar component in case of resurfacing, but also of femoral and tibial components. LEVEL OF EVIDENCE: II.
    Knee Surgery Sports Traumatology Arthroscopy 01/2014; 22(8). DOI:10.1007/s00167-013-2825-0 · 2.84 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study was to determine the reliability and validity of manual measurements of patellar height to standard radiographic measurements in 30 knees of 15 subjects. Patellar height was measured using manual and radiographic methods. The manual measurements were performed by two examiners using digital vernier calipers with the subject sitting and the knees in of flexion. The radiographic measurements were performed in the same position. The reliability of the manual measurements was assessed by means of intraclass correlation coefficients [ICC(3,1)], and the validity was investigated using the Pearson's product-moment correlation coefficient and an independent t-test. The intra- and inter-rater reliabilities of the manual measurement of patellar height were excellent (ICC=.86 and .88 respectively). The validity of patellar height measured manually compared to the radiographic method was good (Pearson's r=.69). In conclusion, the manual method is an objective, qualitative measurement of patella height.
    09/2013; 20(3). DOI:10.12674/ptk.2013.20.3.054
  • [Show abstract] [Hide abstract]
    ABSTRACT: The patellofemoral (PF) joint is a complex articulation, with interplay between the osseous and soft tissue structures to maintain the balance between knee mobility and stability. Disorders of the PF joint can be a source of anterior knee pain (AKP). In this article, radiographic and magnetic resonance imaging of the PF joint are reviewed, including normal anatomy, imaging techniques, and imaging-based measurements. Common imaging findings associated with AKP are reviewed, including symptomatic normal variants, tendinopathy, apophysitis, osteoarthritis, chondromalacia patella, trochlear dysplasia, excessive lateralization of tibial tuberosity, patellar maltracking, patellar dislocation and fractures, anterior bursitis, Morel-Lavallée effusions, and fat pad edema.
    Clinics in Sports Medicine 07/2014; DOI:10.1016/j.csm.2014.03.007 · 2.58 Impact Factor

Full-text

Download
113 Downloads
Available from
May 27, 2014