Background and purpose: In Africa, sickle cell disease is responsible for aseptic osteonecrosis of the femoral head associated with secondary hip osteoarthritis. Primitive hip osteoarthritis appears to be less frequent than in western countries. Very little evidence is known about influence of etiology (primitive and secondary) and radiographic status on pain and disability in Beninese’s patients with hip osteoarthritis. The purpose of this study is to explore the impacts of the etiology of hip osteoarthritis and radiographic status in modifying pain, disability and quality of life in Beninese patients with hip osteoarthritis.

Relevance: This research will improve evaluation and management for patients with hip osteoarthritis in Benin.

Participants: Participants were from the Clinic of Physical Medicine and Rehabilitation at the National Teaching hospital in Cotonou, the economic capital of the Republic of Benin. Forty-nine participants with hip osteoarthritis, (26 men and 23 women) between 11 and 70 years with bilateral or unilateral symptomatic hip osteoarthritis diagnosed by radiography were recruited. Patients were selected between October 2018 and April 2019. All participants with hip osteoarthritis according to American College of Rheumatology classification criteria and/or Kellgren and Lawrence radiographic classification were included.

Method: The assessment based on International Classification of Functioning, Disability and Health model.  The following variables were measured: severity of OA using the Kellgren and Lawrence radiographic classification, pain using the Numerical rating Scale and Oxford Hip Score, range of motion using goniometer, muscle strength using Medical Research Council scale, walking performance using Ten Meter walk test and quality of life using the West Ontario and McMaster University Osteoarthritis Index and Short Form 36.

Analysis: Statistical comparisons between the etiologies performed using a t-test and one-way ANOVA to test the effect of radiographic status on hip osteoarthritis.

Results: Regarding to etiology, there were no significant differences on body structures and function, activity and participation between primitive and secondary hip osteoarthritis. However, there was a statistically significant difference based on radiographic status: pain with p-value of 0.016 and < 0.001 (respectively, for Numerical Rating Scale and Oxford Hip Score); activity with p-value of 0.008 (for 10 Meter Walk Test); for participation with p < 0.001 (for Sort Form-36 and West Ontario and McMaster University Osteoarthritis Index). Patients with grade IV of Kellgren and Lawrence's classification were more affected.

Conclusion: Beninese patients with secondary hip osteoarthritis due to osteonecrosis of the femoral head are no more affected than patients with primary osteoarthritis. As the degeneration of joints progresses, pain and functional disability occurs.

Implications: The knowledge of hip osteoarthritis impact on structures and function, activity and participation for Beninese hip osteoarthritis patients, may help clinicians to evaluate and develop rehabilitation programs to improve functioning and disability for this population.

Keyword: Disability, Functioning, Hip Osteoarthritis.

Funding source/Acknowledgment: No funding source. Authors thank all the participants for their participation in the study.

Ethics approval: This study was approved by the local ethics committee of the Clinic of Physical Medicine and Rehabilitation at the National Teaching hospital of Cotonou (Benin).