Postural analysis and diagnostic imaging of musculoskeletal disorders in captive Asian Elephants (Elephas maximus)

Introduction

Captive Asian elephants (Elephas maximus) face unique challenges that predispose them to musculoskeletal disorders, including restricted mobility, inappropriate substrates, and suboptimal husbandry practices. These conditions contribute to abnormal posture, uneven weight distribution, and progressive foot and limb pathologies, which often remain underdiagnosed due to limited diagnostic access (Clubb & Mason, 2002; Regnault et al., 2017) [2, 10] . Common ailments in captive elephants include pododermatitis, toenail overgrowth, onychia, sole abscesses, phalangeal osteomyelitis, osteoarthritis, and traumatic injuries (Fowler, 2001; Fowler, 2006; Houck, 1993; Schwammer, 2001; West, 2006) [3,4,5,11,13] . The elephant's unique foot structure, combined with its substantial body mass and extended lifespan, exacerbates the risk of degenerative musculoskeletal conditions under chronic mechanical loading (Panagiotopoulou et al., 2012) [9] . Previous studies highlight the prevalence of these disorders. Mikota et al. (1994) reported that 50% of elephants in North American zoos developed foot disorders over an 84-year period, with 64% exhibiting non-foot-related musculoskeletal abnormalities [8] . Similarly, Chandrasekharan et al. (2009) documented 404 of 939 clinical cases in captive elephants involving non-specific conditions, including 55 arthritis cases, with working elephants particularly susceptible [1] . Lewis et al. (2010) found that 33% of surveyed zoos reported foot disorders, 36% noted arthritis, and 18% observed lameness within a single year [6] . Postural indicators, such as valgus or varus deformities, asymmetric weight-bearing, and chronic limb shifting, often signal underlying pathology (Miller et al., 2016) [7] . While radiography is a cornerstone for diagnosing musculoskeletal disorders in elephants (Siegal-Willott et al., 2011; West, 2006) [12,13] , studies correlating postural assessments with radiographic findings are scarce. This study addresses this gap by integrating systematic postural evaluations with radiographic imaging to characterize foot and limb pathologies in captive Asian elephants, aiming to enhance early detection and inform welfare-focused management strategies.

Materials and methods

Study population and facility

This study was conducted at the Elephant Conservation and Care Center (ECCC), operated by Wildlife SOS, which provides advanced veterinary care for rescued Asian elephants (Elephas maximus). Thirty-two rehabilitated elephants were selected based on clinical signs of locomotor deficits, abnormal posture, or documented histories of foot and limb disorders.

Posture and gait assessments

Each elephant underwent systematic visual assessment on level ground, evaluating weight distribution, limb angulation, and compensatory postural adaptations. Gait analysis was performed during ambulation, noting stiffness, lameness, or limb dragging. Foot examinations identified abnormalities, including toenail cracks, splits, infections, pododermatitis, and contusions.

Radiographic imaging

Elephants were conditioned using positive reinforcement to facilitate cooperative radiographic procedures. Imaging was performed with a portable digital high frequency radiography unit (OTOM Mine Alnu, OTOM Co. Ltd.) and a 14×17-inch flat panel detector (LG). Standardized positioning protocols ensured diagnostic-quality images of the carpal, elbow, hock, and stifle joints, as well as digital and sole structures.

Data analysis

Data on postural abnormalities, gait, and radiographic findings were compiled. Descriptive statistics summarized the prevalence of abnormalities, with comparisons drawn between forelimb and hindlimb pathologies. Radiographic findings were categorized by joint and type of pathology (e.g., osteoarthritis, fractures).

Results

Systematic postural assessments revealed forelimb abnormalities in 14 elephants (43.8%) and hindlimb deformities in six (18.8%). Pathological toenails were significantly more prevalent in forelimbs (n = 267) than hindlimbs (n = 161), with central digits (T2 and T3) most affected, suggesting disproportionate biomechanical loading during locomotion (Figures 123). These findings align with prior reports of high foot and joint pathology incidence in captive elephants (Fowler, 2001; Lewis et al., 2010) [3,6] . Radiographic evaluations (n = 20) identified degenerative changes, predominantly in the carpal joints, followed by the hock and elbow joints (Figure 4). Observed abnormalities included osteoarthritis, ankylosis, mineralization, osteitis, enthesopathy, fractures, and bone remodeling (Figures 56789). Carpal joint pathology likely reflects the forelimbs' role in bearing approximately 60% of body weight. Elephants with chronic postural deviations exhibited more pronounced radiographic changes, supporting a link between abnormal biomechanics and secondary osteoarthritis, consistent with prior studies (Fowler, 2006; Mikota et al., 1994) [4,8] . [1,8] and emphasize the need for proactive management, including optimized substrates, regular foot care, and routine diagnostic imaging. Limitations include the study's focus on rescued elephants, which may not fully represent all captive populations, and the lack of longitudinal data to track pathology progression. Future research should explore longitudinal studies and additional diagnostic modalities, such as computed tomography, to further elucidate musculoskeletal pathology in elephants.

Conclusion

This study demonstrates a significant association between postural abnormalities and musculoskeletal pathologies in captive Asian elephants, validated through radiographic imaging. The integration of postural and radiographic assessments enhances the detection of both subclinical and advanced conditions, informing targeted interventions to improve elephant welfare. Proactive management strategies, including appropriate substrates, optimized nutrition, and regular diagnostic evaluations, are critical to mitigating musculoskeletal disorders and enhancing the long-term health of captive elephants.

Acknowledgement

AcknowledgementWe express our gratitude to Mr. Kartick Satyanarayan and Smt. Geeta Seshamani, Co-Founders of Wildlife SOS, for their visionary guidance and support. We also thank the Uttar Pradesh Forest Department for their collaboration and the dedicated animal caregivers at the Elephant Conservation and Care Center for their tireless efforts.

References

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