Is Iron Deficiency Anemia a Risk Factor for Poorer Outcomes in Primary Total Knee Arthroplasty?

Patients undergoing total knee arthroplasty (TKA) commonly have concomitant iron deficiency anemia (IDA). The purpose of this study is to investigate the effect of IDA on (1) total in-hospital lengths of stay (LOS); (2) 90-day readmissions; (3) costs of care; (4) medical complications; and (5) and implant-related complications in patients who underwent primary TKA.

Patients with and without IDA undergoing primary TKA were identified and matched through a nationwide administrative claims database that yielded 94,053 and 470,264 patients, respectively. Primary outcomes that were statistically analyzed included in-hospital LOS, readmission rates, costs of care, medical complications, and implant-related complications.

Patients with IDA had longer in-hospital LOS (4 days vs 3 days; P < .0001), 90-day readmission rates (25.8% vs 16.3%; odds ratio [OR], 1.77; P < .0001), higher day of surgery ($13,079.42 vs $11,758.25; P < .0001), and total global 90-day episode of care costs ($17,635.13 vs $14,439.06; P < .0001) compared to patients who do not have IDA. Furthermore, IDA patients were found to have significantly higher incidence and odds of medical (3.53% vs 1.33%; OR, 2.71; P < .0001) and implant-related (3.80% vs 2.68%; OR, 1.43; P < .0001) complications following primary TKA.

The effect of IDA on TKA outcomes may make a large impact on healthcare usage. We found that patients with IDA had poorer results in all the outcomes that were measured. Orthopedic surgeons can use this information to evaluate the need for IDA interventions before TKA which may contribute to lower rates of morbidity and mortality in TKA.