Vet Comp Orthop Traumatol 2019; 32(02): 126-132
DOI: 10.1055/s-0039-1678550
Original Research
Georg Thieme Verlag KG Stuttgart · New York

Observer Variability of Arthroscopic Cartilage Grading Using the Modified Outerbridge Classification System in the Dog

Mary D. Deweese
1  Department of Clinical Sciences and Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
,
Dorothy C. Brown
2  Elanco Animal Health, Greenfield, Indiana, United States
,
Kei Hayashi
3  Department of Clinical Sciences, Cornell University, Ithaca, New York, United States
,
Cara Blake
4  Department of Veterinary Clinical Sciences, Center for Veterinary Sciences, Oklahoma State University, Stillwater, Oklahoma, United States
,
Elizabeth Anglin
5  Wheat Ridge Animal Hospital, Wheat Ridge, Colorado, United States
,
Katherine Morris
1  Department of Clinical Sciences and Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
,
Kimberly A. Agnello
1  Department of Clinical Sciences and Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
› Author Affiliations
Funding None.
Further Information

Publication History

21 March 2018

04 December 2018

Publication Date:
05 March 2019 (eFirst)

Abstract

Objective The aim of this study was to determine the inter- and intra-observer variability of the modified Outerbridge cartilage classification system in canine joints evaluated via arthroscopy.

Materials and Methods Fifty arthroscopic videos of canine cartilage were scored by six observers, where three of the observers had significant arthroscopic experience and three had minimal to no experience. The kappa (κ) statistic was used to evaluate overall and individual score inter-observer variability, as well as experience variability. The weighted κ statistic was used to evaluate the overall intra-observer variability for each observer, and for individual score intra-observer variability across experience groups. Landis and Koch cut-offs were used to determine strength of agreement associated with each κ-value.

Results The overall inter-and intra-observer variability of the modified Outerbridge cartilage classification system showed fair and substantial strengths of agreement, respectively. The most extreme scores of 0 and 4 had the best inter- and intra-agreement and the middle scores of 1, 2 and 3 had decreased strengths of agreement. Experience of the observer increased the strength of agreement between the scores.

Clinical Significance The modified Outerbridge classification system is an acceptable method for the evaluation of canine cartilage. Observer agreement is improved if the observer has experience with arthroscopy and viewing cartilage changes, and if the same observer is used for subsequent cartilage evaluations.

Author Contribution

Kimberly Agnello and Mary Dell Deweese contributed to conception of study, study design, acquisition of data and data analysis and interpretation. Kei Hayashi, Cara Blake, Katherine Morris and Elizabeth Anglin contributed to conception of study and acquisition of data. Dorothy Brown contributed to conception of study, acquisition of data and data analysis and interpretation. All authors drafted, revised and approved the submitted.