Functional outcome measures in a surgical model of hip osteoarthritis in dogs.

Dianne Little,Jonathan Hash,Stephen Johnson,Steven A Olson,Bradley T Estes,Franklin T Moutos,B Duncan X Lascelles,Farshid Guilak

doi:10.1186/s40634-016-0053-5

Abstract

BackgroundThe hip is one of the most common sites of osteoarthritis in the body, second only to the knee in prevalence. However, current animal models of hip osteoarthritis have not been assessed using many of the functional outcome measures used in orthopaedics, a characteristic that could increase their utility in the evaluation of therapeutic interventions. The canine hip shares similarities with the human hip, and functional outcome measures are well documented in veterinary medicine, providing a baseline for pre-clinical evaluation of therapeutic strategies for the treatment of hip osteoarthritis. The purpose of this study was to evaluate a surgical model of hip osteoarthritis in a large laboratory animal model and to evaluate functional and end-point outcome measures.MethodsSeven dogs were subjected to partial surgical debridement of cartilage from one femoral head. Pre- and postoperative pain and functional scores, gait analysis, radiographs, accelerometry, goniometry and limb circumference were evaluated through a 20-week recovery period, followed by histological evaluation of cartilage and synovium.ResultsAnimals developed histological and radiographic evidence of osteoarthritis, which was correlated with measurable functional impairment. For example, Mankin scores in operated limbs were positively correlated to radiographic scores but negatively correlated to range of motion, limb circumference and 20-week peak vertical force.ConclusionsThis study demonstrates that multiple relevant functional outcome measures can be used successfully in a large laboratory animal model of hip osteoarthritis. These measures could be used to evaluate relative efficacy of therapeutic interventions relevant to human clinical care.Electronic supplementary materialThe online version of this article (doi:10.1186/s40634-016-0053-5) contains supplementary material, which is available to authorized users.

Highlights

The hip is one of the most common sites of osteoarthritis in the body, second only to the knee in prevalence
Radiographic osteoarthritis score was significantly greater in operated than control limbs, demonstrated a progressive increase over time and was significantly increased from preoperative values beginning at 8 weeks postoperatively (Fig. 1B and C)
The large number of clinical and biologically relevant correlations between functional, clinical and end-point outcome measures applied to this model suggest that continued use of complex panels of outcome measures in animals models could contribute to improved understanding of how well animal models of osteoarthritis represent the complexities of clinical disease in both human and animal subjects (Belshaw, 2016; Sharkey, 2013)

Summary

Introduction

The hip is one of the most common sites of osteoarthritis in the body, second only to the knee in prevalence. A major clinical concern is that revision rates of total hip arthroplasty (THA) are nearly 50 % in this age group (Baker et al 2011) (Kim et al 2011), and revised implants have low survivorship and high complication rate compared to primary hip arthroplasty (Adelani et al 2013) This has led to substantial interest in the development of new therapeutic strategies to improve on results of hip arthroplasty or to delay the need for these procedures (Guilak 2010; Lee et al 2010; Warnke 2010; Field et al 2011; Hauser and Orlofsky 2013; Schauss et al 2012; Vilar et al 2013). The requirements for a pre-clinical model of osteoarthritis in which these approaches could

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