Results
From 2010 to 2018, 248,059 primary THAs were done and recorded in the NSQIP database, of which 9,304 cases were excluded for nonelective reasons. Of the 238,755 remaining cases, 3,149 cases (1.3%) were done using some type of intraoperative technology and assigned to the TA-THA cohort. Specifically, 151 (4.8%) were done with fluoroscopically guided navigation (CPT—0054T), 73 (2.3%) with CT/MRI-based technology (CPT—0055T), and 2,925 (92.9%) with imageless navigation (CPT—20985). The annual proportion of patients undergoing TA-THA within the NSQIP data set varied between 2010 and 2018 (Figure 1). On propensity score matching, 2,335 patients in the TA-THA group were successfully matched to 2,335 patients in the U-THA group.
Figure 1.
Graph showing case volume of technology-assisted THA by year within the NSQIP database. NSQIP = National Surgical Quality Improvement Program, THA = total hip arthroplasty
Baseline characteristics were compared between unmatched TA-THA and U-THA study groups, revealing some significant differences between groups (Table 1). Race distribution significantly differed between the study groups (P < 0.001); subgroup analysis revealed that Hispanics, Blacks/African Americans, and Whites were more likely to undergo TA-THA than Asians and Native American/Pacific Islanders. Baseline functional status differed between the study groups (P < 0.001), and there was a higher proportion of "partially dependent" patients in the TA-THA cohort compared with the U-THA cohort (2.6% versus 1.8%, P = 0.01). No significant differences were observed between the study groups regarding sex (P = 0.355), age category (P = 0.406), smoking status (P = 0.290), American Society of Anesthesiologist classification (P = 0.458), body mass index (P = 0.232), and modified frailty index score (P = 0.343). After propensity score matching, there were no notable differences in baseline characteristics between the study groups.
Analysis of surgical times for both unmatched and matched study groups was done (Figure 2,Table 2). For unmatched cohorts, the mean surgical time for the TA-THA group was significantly longer than that of the U-THA group (101.4 ± 33.5 versus 91.5 ± 38.8 minutes, P < 0.001). A significant decrease was observed in surgical times for both technology-assisted (slope = −0.62 min/yr, P = 0.018, R2 = 0.002) and unassisted THA cohorts (slope = −0.837 min/yr, P < 0.001, R2 = 0.002) across the years studied. After adjusting for operation year, significant differences in surgical time between TA-THA and U-THA remained (P < 0.001). In the propensity-matched cohort analysis, there were significantly higher surgical times in the TA-THA cohort compared with the U-THA cohort (101.0 ± 34.0 versus 91.9 ± 38.8 minutes, P < 0.001).
Figure 2.
Graph showing mean surgical time by year of operation for the unmatched TA-THA and U-THA cohorts. TA-THA = technology-assisted total hip arthroplasty, U-THA = unassisted THA
Inpatient hospitalization variables were assessed between matched cohorts to control for notable differences in baseline characteristics. Patients in the TA-THA cohort had significantly shorter mean LOS (2.0 ± 1.1 versus 2.5 ± 2.0 days, P < 0.001). Significant differences were observed in discharge destination between the matched cohorts. In the TA-THA cohort, a higher proportion of patients were discharged home (75.7% versus 85.8%, P < 0.001) and a lower proportion were discharged to rehab/skilled nursing facilities (20.0% versus 11.9%, P < 0.001) when compared with that of the U-THA cohort (Table 2).
The readmission rate in the TA-THA cohort was significantly greater than the U-THA cohort (3.8% versus 2.4%, P = 0.011). Subgroup analysis of readmission diagnosis found significantly increased rates of readmissions for gastrointestinal (0.6% versus 0.1%, P = 0.012) and unspecified THA complication or dislocation (0.5% versus 0.0%, P = 0.004) for TA-THA compared with U-THA. No significant differences were observed in major complication (9.9% versus 10.7%, P = 0.360), revision surgery (2.1% versus 1.5%, P = 0.313), or mortality (0.1% versus 0.1%, P = 0.655) rates for the groups. Subgroup analysis of revision surgery diagnoses found a higher rate of operations unrelated to THA in the TA-THA cohort (0.6% versus 0.2%, P = 0.036) compared with the U-THA cohort. Patients undergoing TA-THA had a lower transfusion rate compared with those undergoing U-THA (5.7% versus 7.8%, P = 0.005). No significant differences were observed in wound infection (P = 0.301), periprosthetic infection (P = 0.548), systemic infection (P = 0.247), deep vein thrombosis or pulmonary embolism (P = 0.823), and cardiac (P = 0.687), respiratory (P = 0.581), neurologic (P = 0.625), or renal (P = 0.317) complications.
J Am Acad Orthop Surg. 2022;30(8):e673-e682. © 2022 American Academy of Orthopaedic Surgeons
