A Proposed Radiologic Scoring System for Osteoarthritis in the Hips and Knees of Nonhuman Primates
Osteoarthritis (OA) is known to cause chronic debilitating changes to the skeletal system in all types of animals. Known for its ability to incapacitate humans, nonhuman primates maintain activity in the face of severe OA, thus challenging assessment of pain. In addition, systematic evaluation of nonhuman primate joints for OA is infrequently applied, and correlates between radiologic changes to the joint and pain in nonhuman primates are lacking.
The aim of this study is to develop a radiologic scoring system for objective assessment of osteoarthritic changes of the hips and knees of nonhuman primates. Ideal joint positioning for different imaging modalities is defined. After review of human OA scoring systems,1-3 four key radiologic parameters are selected for evaluation of the hip joint and the knee joint: joint space narrowing, subchondral sclerosis, osteophyte formation, and bone end deformity. Each joint is scored for each of these four parameters on a five-point scale. Total score for each joint is used to classify the joint as having absent, mild, moderate, severe, or profound osteoarthritis.
A standardized OA scoring system will facilitate thorough evaluation and documentation of joint changes over time. Scores for hip and knee OA can be combined with OA scores of shoulders, elbows, and spine to give an overall assessment of degenerative changes that may cause pain and impact mobility. With heightened awareness of indicators of early OA, targeted medical, behavioral, environmental, and physical interventions may improve animal comfort and welfare and ideally slow the progression of this debilitating disorder.
The authors thank Dr. Emmanuelle Furst and Dr. Megan Freeman for their development of osteoarthritis scoring systems for the spine and shoulders/elbows, respectively.
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