No correlation between race, poverty and risk for TKR failure
CHICAGO — Although it has been shown that risk for total knee replacement revision is higher among black patients compared with white patients, new research presented here concludes that poverty does not alter this risk.
“Blacks are at higher risk of knee replacement (TKR) revision than whites. We wanted to know if that disparity was mediated by poverty,” Anne R. Bass, MD, of the Hospital for Special Surgery and Weill Cornell Medicine, told Healio Rheumatology. “We asked the question because our prior work had shown that when you analyze WOMAC pain and function 2 years after TKR, there are large racial disparities in patients who come from poor neighborhoods, but none when you look at blacks vs. whites from wealthy neighborhoods. The question we had was: Is the same true for TKR revision?”
Bass and colleagues analyzed data from a 2007-2011 prospective, single-institution TKR registry comprising black and white residents of New York. Patients who underwent TKR revision at another institution between 2007 and 2014 were identified using the NY Statewide Planning and Research Cooperative System database.
The researchers used Cox regression to examine predictors of TKR revision and multivariable logistic regression to study predictors of TKR failure. Failure was defined as:
- TKR revision within 2 years of the initial surgery; or
- HSS TKR Satisfaction Quality of Life QOL score reported as not improved or worsened 2 years after surgery.
Patients were linked to their residential census tract using geocoded addresses, and logistic regression assessed the interaction between census tract poverty and TKR failure.
The study included 4,062 TKR in 3,797 patients; mean age was 68.4 ± 10 years, 64% were female, 8% lived in a census tract with >20% under the poverty line, and 9% were black. Three percent of patients required revision (n = 122 of 4,062) and 7% experienced failure (n = 200 of 2,832).
Nearly 1,700 census tracts were represented (n = 1,687) and mean census tract poverty was 7.7%.
Median time from initial surgery to revision was 454 days after surgery. Reasons for TKR revisions were septic in 19% of cases and aseptic in 81%. Aseptic causes included mechanical failure in 75.9%, fracture in 3.7% and other in 1.5%.
Patients who underwent septic revisions were older (67.5 years vs. 62.4 years; P = .028), had a shorter time to revision (6.3 months vs. 17.6 months; P = .018) and had lower volume surgeons (P = .019), according to researchers. Older age (HR = 0.8 per 5 years; 95% CI, 0.73-0.87) and female sex (HR = 0.64; 95% CI, 0.45-0.92) were protective, while constrained prosthesis type 2.31 (95% CI, 1.42-3.76) increased TKR revision risk, according to multivariable analysis.
At 2 years, 7% of cases resulted in TKR failure. Risk factors for TKR failure in multivariable analysis included low surgeon volume (OR = 3.08; 95% CI, 1.61-5.90) while high HSS expectation score (OR = 0.84; 95% CI, 0.75-0.94) and osteoarthritis indication for surgery (OR = 0.37; 95% CI, 0.16-0.82) were protective.
“Poverty doesn't play into the risk of TKR revision or TKR failure, at least not in our cohort of patients, all of whom had surgery at HSS, a high-quality, high-volume hospital,” Bass said. “Our total cohort included almost 5,000 TKR patients and our study was also notable for the fact that we linked our registry to a statewide database, so we were able to identify revisions done, even if the patient went to a different hospital. The study suggests that the factors contributing to TKR revision risk differ from those influencing 2-year patient reported outcomes and may have more to do with factors introduced at the time of surgery” – by Stacey L. Adams
Disclosure: Bass reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
Bass AR. Abstract 263. Presented at ACR/ARHP Annual Meeting, Oct. 20-24, 2018; Chicago.