Abstract
BackgroundAn accelerometer-based handheld navigation system (HHNS) for total knee arthroplasty (TKA) does not require a large console needed for computer-assisted navigation systems and has been shown to decrease component malalignment in TKA. The study aimed to use HHNS with conventional instrumentation to compare the radiological evaluation and functional outcomes of TKA.Materials and methodsThis was a multi-surgeon, prospective, assessor-blinded comparative study of 122 patients undergoing unilateral TKA. We used a stratified randomized sampling method to select 35/48 patients undergoing TKA using a handheld navigation system and 35/74 patients undergoing TKA using conventional instrumentation and divided them into two groups: the HHNS group and (conventional) CONV group. Postoperative radiographic evaluation was based on the tibial and femoral alignment angle, posterior tibial slope, and tibiofemoral angle measured from full-length lower-limb anteroposterior and lateral views of the knee. The Oxford Knee Score (OKS) and Knee Society Score (KSS) with a two-year serial follow-up were used to evaluate functional outcomes.ResultsThe mean tibial alignment angle and posterior tibial slope were 0.78° ± 1.27° and 4.38° ± 0.86°, respectively, in the HHNS cohort and 2.63° ± 1.54° and 2.12° ± 1.82°, respectively, in the CONV group (p < 0.001). There was no significant difference in the femoral alignment angles. The overall alignment using the mean tibiofemoral angle was 179.21° ± 1.82° in the HHNS group and 177.31° ± 2.18° in the CONV group (p = 0.002). There were no significant differences in the KSS and OKS at the two-year follow-up between the groups.ConclusionsThe use of HHNS in TKA significantly increased accuracy in limb and implant alignment, but there was no significant difference in the two-years functional outcomes.
Highlights
Total knee arthroplasty (TKA) is an established procedure for treating advanced knee arthritis
There was no significant difference in the femoral alignment angles
There were no significant differences in the Knee Society Score (KSS) and Oxford Knee Score (OKS) at the two-year follow-up between the groups
Summary
Total knee arthroplasty (TKA) is an established procedure for treating advanced knee arthritis. Good surgical technique and instrumentation leading to accurate mechanical axis alignment and appropriate soft-tissue balancing are required for the long-term survival of implants and for better functional outcomes [1,2]. Mechanical alignment guides developed to achieve accurate postoperative mechanical axis alignment would be systems based on intramedullary or extramedullary rods. There have been significant degrees of errors in mechanical axis alignment (>3°) ranging from 22% to 35% for routine TKAs using conventional instrumentation [2]. Computer-assisted surgery (CAS) navigation, handheld navigation systems, and patient-matched instrumentation have been developed as alternatives to conventional instrumentation to minimize these errors. An accelerometer-based handheld navigation system (HHNS) for total knee arthroplasty (TKA) does not require a large console needed for computer-assisted navigation systems and has been shown to decrease component malalignment in TKA.
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