Interobserver variation in the measurement of patellar height after total knee arthroplasty

Rogers, Benedict A.; Thornton-Bott, P.; Cannon, Stephen R.; Briggs, Twr

doi:10.1302/0301-620x.88b4.16407

Cited by 74 publications

(57 citation statements)

References 16 publications

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“…Our findings were better than those in previous studies [21,22]. This was a prospective study in which all volunteers were recruited and underwent radiographic examination under identical conditions.…”

Section: Discussioncontrasting

confidence: 83%

Novel method of measuring patellar height ratio using a distal femoral reference point

Chareancholvanich

Narkbunnam

2011

International Orthopaedics (SICOT)

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Purpose Patellar height is an important factor in patellar tracking and alters the force of the patellofemoral joint reaction. Several methods for measuring patellar height ratio have been described, with no single method recognised as a gold standard. This study developed a new measurement method using a distal femoral reference, where the normal values of measurement are unaffected by varying angles of knee flexion. Methods Eighty-five volunteers had radiographs taken of their knees at 0°, 15°, 30°, 45°and 60°of flexion in a supine position. Patellar height was assessed by five different measurement methods: Insall-Salvati (IS), modified InsallSalvati (MIS), Caton-Deschamps (CD), Blackburne-Peel (BP) and our new method. Three independent examiners sequentially conducted all measurements under identical conditions. Results The normal value obtained with the method reported here was 1 ± 0.1standard deviation (SD) (IS 1.1 ± 0.2, MIS 1.8 ± 0.25, CD 1.08 ± 0.2, BP 0.9 ± 0.2). IS and the new method tended to have better reliability in the face of varying knee-flexion angles than did CD, BP or MIS. All methods had good to excellent levels of interobserver variation (IS 0.969, new method 0.811, MIS 0.768, CD 0.735, BP 0.708). Conclusion The new patellar height ratio measurement method proved to be accurate and reproducible for evaluating a normal population. This method offered the benefit of using the distal femur as a reference landmark, and, thus, the resulting measurements were not altered by varying degrees of knee flexion.

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Section: Discussioncontrasting

confidence: 83%

Novel method of measuring patellar height ratio using a distal femoral reference point

Chareancholvanich

Narkbunnam

2011

International Orthopaedics (SICOT)

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“…The Blackburne-Peel index was used to define patellar height. [15][16][17] Five different heights were tested: Blackburne-Peel indices of 0.59 (the lowest), 0.73, 0.84 (normal), and 1.0 and 1.29 (patella alta). Lateral photographs were taken in a standardised way at the beginning and end of each experiment, with the knee loaded in 30° of flexion.…”

Section: Methodsmentioning

confidence: 99%

Is there a biomechanical explanation for anterior knee pain in patients with patella alta?

Luyckx¹,

Didden²,

Vandenneucker³

et al. 2009

The Journal of Bone and Joint Surgery. British volume

138

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The purpose of this study was to test the hypothesis that patella alta leads to a less favourable situation in terms of patellofemoral contact force, contact area and contact pressure than the normal patellar position, and thereby gives rise to anterior knee pain.A dynamic knee simulator system based on the Oxford rig and allowing six degrees of freedom was adapted in order to simulate and record the dynamic loads during a knee squat from 30° to 120° flexion under physiological conditions. Five different configurations were studied, with variable predetermined patellar heights.The patellofemoral contact force increased with increasing knee flexion until contact occurred between the quadriceps tendon and the femoral trochlea, inducing load sharing. Patella alta caused a delay of this contact until deeper flexion. As a consequence, the maximal patellofemoral contact force and contact pressure increased significantly with increasing patellar height (p < 0.01). Patella alta was associated with the highest maximal patellofemoral contact force and contact pressure. When averaged across all flexion angles, a normal patellar position was associated with the lowest contact pressures.Our results indicate that there is a biomechanical reason for anterior knee pain in patients with patella alta.Anterior knee pain may be present in as many as 30% of physically active individuals.

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“…Several methods have been described for the estimation of the patellar height [1][2][3][4][5][6][7]. All these methods have pros and cons and possess different values of inter-and intraobserver variability, reliability and reproducibility [8][9][10][11][12]. Despite numerous proposals, there is still no method which precisely describes the true patellar height in relation to the tibiofemoral joint, with high values of reliability and reproducibility and low values of inter-and intraobserver variability.…”

Section: Introductionmentioning

confidence: 99%

Comparison of five patellar height measurement methods in 90° knee flexion

Anagnostakos

Lorbach

Reiter

et al. 2011

International Orthopaedics (SICOT)

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Purpose The aim of this prospective study was to evaluate the patellar height in 90°knee flexion. Methods A total of 85 patients with 95 knee joints were included in the study. Patellar height was measured according to the Blackburne-Peel, Labelle-Laurin, InsallSalvati, Linclau, and Caton-Deschamps methods in the whole group and in subgroups based on age, gender, and side.Results The BP-ratio showed a patella norma in 45 cases, and in 25 cases a patella alta and infera, respectively. The Labelle-Laurin method determined a patella norma in eight knees, in 35 a patella alta and in 52 a patella infera. The ISratio revealed a patella norma in 52 patients, a patella alta in six and in 37 a patella infera. The Linclau method demonstrated in 52 cases a patella norma, in 17 a patella alta and in 26 a patella infera. The CD-ratio showed the highest values of a patella norma among all tested methods in 67 knees, whereas a patella alta was evident in 13 and a patella infera in 15 cases. In the subgroups, discrepancies depended on the subgroup and method used. Conclusions Our results demonstrate a method-dependent discrepancy in the measurement of patellar height. A future study should evaluate this effect in a direct comparison between 30°and 90°knee flexion.

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Interobserver variation in the measurement of patellar height after total knee arthroplasty

Cited by 74 publications

References 16 publications

Novel method of measuring patellar height ratio using a distal femoral reference point

Novel method of measuring patellar height ratio using a distal femoral reference point

Is there a biomechanical explanation for anterior knee pain in patients with patella alta?

Comparison of five patellar height measurement methods in 90° knee flexion

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