Comparison of adverse events rates and hospital cost between customized individually made implants and standard off-the-shelf implants for total knee arthroplasty

Abstract

Background: This study compares selected hospital outcomes between patients undergoing total knee arthroplasty (TKA) using either a customized individually made (CIM) implant or a standard off-the-shelf (OTS) implant.

Methods: A retrospective review was conducted on 248 consecutive TKA patients treated in a single institution, by the same surgeon. Patients received either CIM (126) or OTS (122) implants. Study data were collected from patients' medical record or the hospital's administrative billing record. Standard statistical methods tested for differences in selected outcome measures between the 2 study arms.

Results: Compared with the OTS implant study arm, the CIM implant study arm showed significantly lower transfusion rates (2.4% vs 11.6%; P = .005); a lower adverse event rate at both discharge (CIM 3.3% vs OTS 14.1%; P = .003) and 90 days after discharge (CIM 8.1% vs OTS 18.2%; P = .023); and a smaller percentage of patients were discharged to a rehabilitation or other acute care facility (4.8% vs 16.4%; P = .003). Total average real hospital cost for the TKA hospitalization between the 2 groups were nearly identical (CIM $16,192 vs OTS $16,240; P = .913). Finally, the risk-adjusted per patient total cost of care showed a net savings of $913.87 (P = .240) per patient for the CIM-TKA group, for bundle of care including the preoperative computed tomography scan, TKA hospitalization, and discharge disposition.

Conclusions: Patients treated with a CIM implant had significantly lower transfusion rates, fewer adverse event rates, and were less likely to be discharged to a rehabilitation facility or another acute care facility. These outcomes were achieved without increasing costs.

Keywords: Adverse event rate; Customized individually made implant; Hospital cost; Length of stay; TKA.

Figure 1

The distribution of observed hospital LOS by study arm for selected LOS intervals. Note: the chi-squared test of difference for the reported distribution in the figure was not significant (P = .123). However, a 1-sided Fisher exact test found that a significantly greater proportion of patients in the CIM arm were being discharged from their TKA hospitalization in <3 days (<72 hours from admission to discharge) than in the OTS arm (42.1% vs 30.3%; P = .037).

Figure 2

The discharge distribution of patients from their TKA hospitalization by study arm. The chi-squared test for differences in the discharge distribution among the 3 categories shown between the 2 study arms is statistically significant (P = .011). However, the chi-squared test for differences in each discharge location separately, only reached statistical significances for rehabilitation or other facilities (P = .003).