Poster 316: Prevalence and Risk Factors for Total Knee Arthroplasty after Cruciate Ligament Surgery: A Study of the UK BioBank

Abstract

Objectives:

The purpose of this study is to determine an individual’s age-specific prevalence of total knee arthroplasty (TKA) and revision TKA after ACL reconstruction (ACLr) and to identify clinical and genetic risk factors associated with undergoing TKA.

Methods:

The UK Biobank – a prospective cohort of 500,000 adults (age 40-69 at time of enrollment) containing health, physical measures, genotyping data, and linked data on hospitalizations – was utilized to identify individuals with a history of ACL surgery (i.e., “cruciate ligament surgery”) during initial health interviews. Individuals were considered to have progressed to end-stage knee osteoarthritis requiring arthroplasty (i.e., “osteoarthritis”) if they endorsed a procedural history of TKA at time of enrollment or underwent hospitalization with a procedural code for TKA after enrollment in the Biobank cohort. To define an individual’s relative risk of TKA following ACLr, age-specific cumulative incidence of TKA was compared between patients WITH and WITHOUT a history of ACLr. To determine clinical risk factors associated with undergoing TKA after ACLr, age-adjusted logistic regression modeling was utilized to calculate odds ratios (OR) for undergoing TKA. A Manhattan plot was constructed to analyze the relationship between single nucleotide polymorphisms and risk of TKA after ACLr.

Results:

A total of 2,576 individuals with a history of ACLr were identified, with 290 (11.3%) undergoing TKA. In patients with prior ACLr, prevalence of TKA was 0.75% at 45 years of age, 9.1% at 65 years of age, and 20.43% at 80 years of age (Figure 1). Patients with prior ACLr were 4.6x more likely to have undergone TKA by age 55. In the ACLr cohort, BMI >30 kg/m²(odds ratio = 4.01, 95% confidence interval = 2.74–5.87) (Table 1),  a job that always involved heavy manual or physical labor (odds ratio=2.72, 95% confidence interval=1.57-4.71) or walking and standings (odds ratio=2.58, 95% confidence interval=1.58–4.20) were associated with greater TKA prevalence. After adjusting for age, no difference was noted in revision rates between individuals with TKA after ACLr and individuals undergoing TKA without a history of ACLr (Figure 2). No SNP was associated with undergoing TKA after ACLr (Figure 3).

Conclusions:

Patients with prior ACLr are 4.6x more likely to undergo TKA by age 55 than the general population. Patients with BMI >30 and jobs that involve heavy manual labor or walking/standing are at greatest risk for undergoing TKA. These data can be used to counsel patients at time of index ACLr on both their life-time risk of TKA and lifestyle modifications that may limit the need for future TKA. After adjusting for age, ACLr was not independently associated with revision TKA.

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