A pilot study of the association between tobacco use and mid-term outcomes following total hip replacement

Cook, W.A.; Smith, Lindsay K

Abstract

Introduction: Smoking is an important and modifiable risk factor in many disease processes. The detrimental effects of smoking are numerous and well documented with smokers being at increased risk of respiratory disease, cardiovascular disease and many types of cancer. Smoking is also know to adversely affect the survival of dental implants. Although there is a growing body of evidence highlighting the negative effects of smoking within orthopaedics, the focus tends to be on short term outcomes with a distinct lack of evidence regarding the longer term consequences of smoking after total hip replacement or total knee replacement, particularly at mid-term and before failure or revision. This study aimed to address the question of whether smoking status is associated with a poorer outcome after total hip replacement by evaluating patients at mid-term review (6-9 years).
Objectives: The objectives were to compare a validated patient reported outcome measure (Oxford Hip Score) and radiographic changes around the total hip replacement in patients of different smoking status – smoker, non-smoker and ex-smoker – at mid-term review.
Methods: An existing database of 1332 patients was used to identify patients who had undergone arthroplasty review between 2006 and 2013 in a district general hospital. A case-cohort method was employed: patients who smoked, had a total hip arthroplasty and were reviewed between six and nine years after primary surgery were matched by gender, age, type of hip replacement and comorbidity score (Charlson) to a group of non-smokers and to a group of ex-smokers. A priori calculations indicated that a sample size of at least 23 in each group would be needed to detect a statistically significant difference in Oxford hip score (OHS) with alpha value of 5% (0.05) and statistical power of 80%. Demographic details and outcome scores were retrieved on all patients, entered into a spreadsheet and anonymised. All digital radiographic images (antero-posterior pelvis and iliac oblique lateral) were reviewed and changes (radiolucency, component migration, osteolysis, heterotrophic ossification) recorded manually and then entered into the spreadsheet. The non-parametric Kruskal-Wallis test was used to statistically compare the OHS scores and radiographic changes were categorized and compared between the groups.
Results: Three groups of smokers, non-smokers and ex smokers (n=31 in each) were identified from the database. The Kruskal-Wallis test showed that there was no significant difference in OHS between any of the three groups (p=0.83). The Median OHS was 5 (IQR 1-16) in smokers, 6 (IQR 0-15) in ex-smokers and 4 (IQR 1-12.5) in non-smokers. The radiographic review showed that the changes around the components of the hip replacement that
indicated deterioration in fixation or bone quality were greatest in the group of smokers.
Conclusions: The results of this study show that, at mid-term review, there is no significant difference in the Oxford Hip Score between smokers, non-smokers and ex smokers, indicating that patient perception of discomfort and function is similar in all three groups. However, there was evidence of greater underlying bony deterioration in those who are smokers, which may have implications for the long term survival of the total hip replacement in this group.

Citation

Cook, W., & Smith, L. K. (2014, February). A pilot study of the association between tobacco use and mid-term outcomes following total hip replacement. Poster presented at Annual Conference of the British Hip Society 2014, Exeter

• Presentation Conference Type: Poster
• Conference Name: Annual Conference of the British Hip Society 2014
• Conference Location: Exeter
• Start Date: Feb 27, 2014
• End Date: Feb 28, 2014
• Publication Date: Feb 1, 2014
• Deposit Date: Sep 23, 2015
• Publicly Available Date: Dec 2, 2016
• Peer Reviewed: Peer Reviewed
• Keywords: hip, replacement, arthroplasty, tobacco, smoking, bone health, x-ray, follow-up, surveillance
• Public URL: https://uwe-repository.worktribe.com/output/821482
• Publisher URL: https://www.britishhipsociety.com/main?page=Past%20BHS%20Meetings
• Additional Information: Title of Conference or Conference Proceedings : British Hip Society, Annual conference, Exeter 2014