title: Flexion following hip resurfacing and factors that influence it.
abstract: Flexion following arthroplasty of the hip is important for activities of daily living. Studies have highlighted a possible reduction in flexion following Metal-on-Metal Hip Resurfacing Arthroplasty (MoMHRA) but failed to account for inter-subject variability and the possible etiology for this reduction. This in vivo study aims to determine whether flexion is restored following MoMHRA and identify factors that influence it. Charnley Class A patients (n=112) that underwent MoMHRA were reviewed in a dedicated clinic assessing flexion (resurfaced and contra-lateral hips) and outcome. The difference in flexion between both hips was defined as flexion deficit (δflexion). Various patient (age, gender, BMI) and surgical (component orientation, size, head-neck-ratio, offset) factors were examined in terms of their effect on δflexion. MoMHRA-hips had significantly reduced flexion as compared to the native hips. This flexion-deficit correlated with contra-lateral maximum flexion, component size, head-neck-ratio and component orientation. The findings demonstrate that flexion following MoMHRA is strongly correlated to but is reduced in comparison to the native, disease-free, hip flexion. Surgical practice can minimise flexion-deficit and optimise function.
authors: Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Botnar Research Centre, Nuffield Orthopaedic Centre, Oxford, UK. george.grammatopoulos@ndorms.ox.ac.uk
authors: George
authors: G
authors: Grammatopoulos
authors: Andrew
authors: A
authors: Philpott
authors: Kathleen
authors: K
authors: Reilly
authors: Hemant
authors: H
authors: Pandit
authors: Karen
authors: K
authors: Barker
authors: David W
authors: DW
authors: Murray
authors: Harinderjit S
authors: HS
authors: Gill
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D002983:Clinical Competence; D005260:Female; D006621:Hip Joint / Q000503:physiopathology / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D061825:Metal-on-Metal Joint Prostheses; D008875:Middle Aged; D011183:Postoperative Complications; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D020127:Recovery of Function; D011795:Surveys and Questionnaires