The accelerometer-based navigation system demonstrated superior radiological outcomes in restoring mechanical alignment and component sagittal positioning in total knee arthroplasty

Abstract

Background This study aimed to determine whether the accelerometer-based navigation (ABN) could improve the accuracy of restoring mechanical axis (MA), component positioning, and clinical outcomes compared to conventional (CON) total knee arthroplasty (TKA). Methods A total of 301 consecutive patients (ABN: 27, CON: 274) were included. A 1:4 propensity score matching (PSM) was performed between the two groups according to preoperative demographic and clinical parameters. The postoperative MA, femoral coronal angle (FCA), femoral sagittal angle (FSA), tibial coronal angle (TCA) and tibial sagittal angle (TSA) were compared. Absolute deviations of aforementioned angles were calculated as the absolute value of difference between the exact and ideal value and defined as norms if within 3°, otherwise regarded as outliers. Additional clinical parameters, including the Knee Society knee and function scores (KSKS and KSFS) and range of motion (ROM), were assessed at final follow-up (FU) (mean FU was 21.88 and 21.56 months respectively for ABN and CON group). A secondary subgroup analysis and comparison on clinical outcomes were conducted between norms and outliers in different radiological parameters. Results A total of 98 patients/102 knees were analyzed after the PSM (ABN: 21 patients/24 knees, CON: 77 patients/78 knees). In the ABN group, the mean MA, FCA and TSA were significantly improved (p = 0.019, 0.006, < 0.001, respectively). Proportions of TKAs within a ± 3°deviation were significantly improved in all the postoperative radiological variables except for TCA (p = 0.003, 0.021, 0.042, 0.013, respectively for MA, FCA, FSA, and TSA). The absolute deviations of FSA and TSA were also significantly lower in the ABN group (p = 0.020, 0.048, respectively). No significant differences were found in either mean value, absolute deviation or outlier ratio of TCA between two groups. On clinical outcomes, there were no significant differences between two groups, although KSKS, KSFS and ROM (p < 0.01, respectively) dramatically improved compared to baseline. The subgroup analysis also demonstrated no statistical difference on clinical outcomes between the outliers and norms in varied radiological parameters. Conclusions The ABN could improve the accuracy and precision of mechanical alignment and component positioning without significant improvement of clinical outcomes. Further high quality studies with long term FU are warranted to comprehensively evaluate the value of the ABN.

Alignment accuracy and functional outcomes between hand-held navigation and conventional instruments in TKA: a randomized controlled trial

“…The most recent retrospective study by Gao et al compared 24 patients who had the hand-held accelerometer-based navigation assistance with 274 propensity-score-matched patients who received conventional instruments. Similarly, they found no significant differences in physical performances (ROM and KSS) and quality of life (EQ-5D) at 0.5, 1, and 2 years of follow-up [21]. However, the present study delivered concordant results to these previous studies, showing no significant improvement in functional outcomes, including health-related quality of life, in favor of the accelerometer-based navigation system as has been hypothesized.…”

“…Several previous studies have shown that the hand-held accelerometer-based navigation system could optimize the accuracy of the surgical alignments compared to conventional instruments [14][15][16][17][18][19][20][21]. Two recent systematic reviews reported favorable results of HKA, FCA, and TCA in favor of the innovative technique; however, only small effect sizes and inconclusive results were observed in FSA [22,23].…”

“…In previous studies, the iAssist system have failed to deliver better physical performances and quality of life compared to the conventional technique [18][19][20][21]. Unfortunately, most of these studies evaluated only short-term outcomes, and only a few studies have reported these outcomes at or after two years post-operation.…”

“…Few research have compared hand-held accelerometer-based navigation to conventional instruments. [18][19][20][21]. Also, no randomized controlled trial has been conducted to evaluate its functional outcomes at at least two years of follow-up.…”

Accelerometer-Based Handheld Navigation Instrumentation in Total Knee Arthroplasty Decrease Blood Loss Compared to Conventional Instrumentation: A Prospective Comparative Study

“…The newer instrumentation used for TKA, like computer navigation, robotic surgery, etc., is expected to give more accurate alignment of components leading to improved longevity of the implant. HHNS is an accelerometer-based navigation device that guides the surgeon for the more accurate distal femur and proximal tibial cuts avoiding component malalignment when compared to conventional instrumentation [11,[14][15][16]. Furthermore, HHNS does not need to breach the intramedullary cavity in the femur, decreasing blood loss, but there is limited evidence in the literature suggesting this.…”