<b><span style="font-family:Verdana;">Background: </span></b><span style="font-family:Verdana;">The number of total knee arthroplasty (TKA) surgeries performed each ye...<b><span style="font-family:Verdana;">Background: </span></b><span style="font-family:Verdana;">The number of total knee arthroplasty (TKA) surgeries performed each year is increasing worldwide and mechanical alignment (MA) is currently seen as the gold standard procedure. However, taking neutral alignment as the universal goal may be mistaken. In our hospital, we currently conduct kinematically aligned TKA (KA-TKA). Three different types of implants are used</span><span style="font-family:Verdana;">:</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the cruciate-retaining (CR) type, cruciate-sacrificing (CS) type, or bi-cruciate-retained (BCR) type. We aimed to compare the coronal alignment observed following KA-TKA and MA-TKA and in normal knees, as well as that achieved with different types of implants. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> The study comprised 206 knees of Japanese patients who underwent KA-TKA using varying implants in our Hospital between May 2019 and April 2020. Measurements of pre- and postoperative coronal alignment were determined from weight-bearing full-leg standing radiographs. The postoperative results were </span><span style="font-family:Verdana;">compared to measurements taken from patients who underwent MA-TKA (</span><span style="font-family:Verdana;">N = 96) and normal knees (N = 60). </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">No significant differences between the KA-TKA group and normal knees were found for the medial proximal tibial angle (MPTA) (–4.2<span style="white-space:nowrap;">°</span> </span></span><span style="font-family:;" "=""><span style="font-family:Verdana;">±</span><span style="font-family:Verdana;"> 2.6<span style="white-space:nowrap;">°</span> vs –3.8<span style="white-space:nowrap;">°</span> </span><span style="font-family:Verdana;">±</span><span style="font-family:Verdana;"> 2.5<span style="white-space:nowrap;">°</span>) or joint line orientation angle (JLOA) (0.2<span style="white-space:nowrap;">°</span> </span><span style="font-family:Verdana;">±</span><span style="font-family:Verdana;"> 1.9<span style="white-space:nowrap;">°</span> vs 0.3<span style="white-space:nowrap;">°</span> </span><span style="font-family:Verdana;">±</span><span><span style="font-family:Verdana;"> 1.4<span style="white-space:nowrap;">°</span>). However, when MA-TKA was compared to KA-TKA and normal knees, there were significant differences in both the MPTA and JLOA (</span><i><span style="font-family:Verdana;">p </span></i><span style="font-family:Verdana;">< 0.01). Furthermore, for the different implant types, MPTA exhibited significantly greater varus alignment when a CS-type was used than with the other two. </span><b><span style="font-family:Verdana;">Conclusions:</span></b><span style="font-family:Verdana;"> Here, we demonstrated that following KA-TKA, the articular surface of the tibia exhibited a similar varus alignment as that of normal knees, meaning that the technique reproduces the native knee. Furthermore, KA is patient-specific, and does not have the same failures as MA-TKA. Therefore, we anticipate a paradigm shift from mechanical to kinematic alignment, which may help reduce the dissatisfaction rate of TKA patients.</span></span></span>展开更多
Achieving optimal alignment in total knee arthroplasty(TKA) is a critical factor in ensuring optimal outcomes and long-term implant survival. Traditionally, mechanical alignment has been favored to achieve neutral pos...Achieving optimal alignment in total knee arthroplasty(TKA) is a critical factor in ensuring optimal outcomes and long-term implant survival. Traditionally, mechanical alignment has been favored to achieve neutral postoperative joint alignment. However, contemporary approaches, such as kinematic alignments and hybrid techniques including adjusted mechanical, restricted kinematic, inverse kinematic, and functional alignments, are gaining attention for their ability to restore native joint kinematics and anatomical alignment, potentially leading to enhanced functional outcomes and greater patient satisfaction. The ongoing debate on optimal alignment strategies considers the following factors: long-term implant durability, functional improvement, and resolution of individual anatomical variations. Furthermore, advancements of computer-navigated and robotic-assisted surgery have augmented the precision in implant positioning and objective measurements of soft tissue balance. Despite ongoing debates on balancing implant longevity and functional outcomes, there is an increasing advocacy for personalized alignment strategies that are tailored to individual anatomical variations. This review evaluates the spectrum of various alignment techniques in TKA, including mechanical alignment, patient-specific kinematic approaches, and emerging hybrid methods. Each technique is scrutinized based on its fundamental principles, procedural techniques, inherent advantages, and potential limitations, while identifying significant clinical gaps that underscore the need for further investigation.展开更多
Mechanically aligned total knee arthroplasty (TKA) for valgus knee is considered a “challenging surgery.” Recently, the kinematic alignment (KA) method has gained attention. This study aimed to present objective cli...Mechanically aligned total knee arthroplasty (TKA) for valgus knee is considered a “challenging surgery.” Recently, the kinematic alignment (KA) method has gained attention. This study aimed to present objective clinical data, such as intraoperative balance assessment and radiographic evaluation of postoperative lower extremity alignment after TKA using the KA method for valgus deformity. Twenty-one TKA knees (mean age, 74 years;2 males, 19 females) with KA for severe valgus deformity (hip-knee-ankle-angle ≥ 10°) performed at our department in the past 3 years were included in this study. Intraoperative gap and balance measurements and postoperative radiographic evaluation were performed. A total arc of range of motion was achieved up to 98% of preoperative values at 3 weeks postoperatively. Intraoperative gap and balance were stable throughout the entire range of motion. In addition, there were no statistically significant differences in either balance or gap values at each flexion angle. KA TKA is a “simple surgery” rather than a “challenging surgery” because additional soft tissue procedures are not required, operative time is short, intraoperative and postoperative balance is very stable, and a good alignment is achieved. This procedure may relieve surgeons of the stress of TKA for valgus deformities.展开更多
文摘<b><span style="font-family:Verdana;">Background: </span></b><span style="font-family:Verdana;">The number of total knee arthroplasty (TKA) surgeries performed each year is increasing worldwide and mechanical alignment (MA) is currently seen as the gold standard procedure. However, taking neutral alignment as the universal goal may be mistaken. In our hospital, we currently conduct kinematically aligned TKA (KA-TKA). Three different types of implants are used</span><span style="font-family:Verdana;">:</span><span style="font-family:;" "=""><span style="font-family:Verdana;"> the cruciate-retaining (CR) type, cruciate-sacrificing (CS) type, or bi-cruciate-retained (BCR) type. We aimed to compare the coronal alignment observed following KA-TKA and MA-TKA and in normal knees, as well as that achieved with different types of implants. </span><b><span style="font-family:Verdana;">Methods:</span></b><span style="font-family:Verdana;"> The study comprised 206 knees of Japanese patients who underwent KA-TKA using varying implants in our Hospital between May 2019 and April 2020. Measurements of pre- and postoperative coronal alignment were determined from weight-bearing full-leg standing radiographs. The postoperative results were </span><span style="font-family:Verdana;">compared to measurements taken from patients who underwent MA-TKA (</span><span style="font-family:Verdana;">N = 96) and normal knees (N = 60). </span><b><span style="font-family:Verdana;">Results: </span></b><span style="font-family:Verdana;">No significant differences between the KA-TKA group and normal knees were found for the medial proximal tibial angle (MPTA) (–4.2<span style="white-space:nowrap;">°</span> </span></span><span style="font-family:;" "=""><span style="font-family:Verdana;">±</span><span style="font-family:Verdana;"> 2.6<span style="white-space:nowrap;">°</span> vs –3.8<span style="white-space:nowrap;">°</span> </span><span style="font-family:Verdana;">±</span><span style="font-family:Verdana;"> 2.5<span style="white-space:nowrap;">°</span>) or joint line orientation angle (JLOA) (0.2<span style="white-space:nowrap;">°</span> </span><span style="font-family:Verdana;">±</span><span style="font-family:Verdana;"> 1.9<span style="white-space:nowrap;">°</span> vs 0.3<span style="white-space:nowrap;">°</span> </span><span style="font-family:Verdana;">±</span><span><span style="font-family:Verdana;"> 1.4<span style="white-space:nowrap;">°</span>). However, when MA-TKA was compared to KA-TKA and normal knees, there were significant differences in both the MPTA and JLOA (</span><i><span style="font-family:Verdana;">p </span></i><span style="font-family:Verdana;">< 0.01). Furthermore, for the different implant types, MPTA exhibited significantly greater varus alignment when a CS-type was used than with the other two. </span><b><span style="font-family:Verdana;">Conclusions:</span></b><span style="font-family:Verdana;"> Here, we demonstrated that following KA-TKA, the articular surface of the tibia exhibited a similar varus alignment as that of normal knees, meaning that the technique reproduces the native knee. Furthermore, KA is patient-specific, and does not have the same failures as MA-TKA. Therefore, we anticipate a paradigm shift from mechanical to kinematic alignment, which may help reduce the dissatisfaction rate of TKA patients.</span></span></span>
文摘Achieving optimal alignment in total knee arthroplasty(TKA) is a critical factor in ensuring optimal outcomes and long-term implant survival. Traditionally, mechanical alignment has been favored to achieve neutral postoperative joint alignment. However, contemporary approaches, such as kinematic alignments and hybrid techniques including adjusted mechanical, restricted kinematic, inverse kinematic, and functional alignments, are gaining attention for their ability to restore native joint kinematics and anatomical alignment, potentially leading to enhanced functional outcomes and greater patient satisfaction. The ongoing debate on optimal alignment strategies considers the following factors: long-term implant durability, functional improvement, and resolution of individual anatomical variations. Furthermore, advancements of computer-navigated and robotic-assisted surgery have augmented the precision in implant positioning and objective measurements of soft tissue balance. Despite ongoing debates on balancing implant longevity and functional outcomes, there is an increasing advocacy for personalized alignment strategies that are tailored to individual anatomical variations. This review evaluates the spectrum of various alignment techniques in TKA, including mechanical alignment, patient-specific kinematic approaches, and emerging hybrid methods. Each technique is scrutinized based on its fundamental principles, procedural techniques, inherent advantages, and potential limitations, while identifying significant clinical gaps that underscore the need for further investigation.
文摘Mechanically aligned total knee arthroplasty (TKA) for valgus knee is considered a “challenging surgery.” Recently, the kinematic alignment (KA) method has gained attention. This study aimed to present objective clinical data, such as intraoperative balance assessment and radiographic evaluation of postoperative lower extremity alignment after TKA using the KA method for valgus deformity. Twenty-one TKA knees (mean age, 74 years;2 males, 19 females) with KA for severe valgus deformity (hip-knee-ankle-angle ≥ 10°) performed at our department in the past 3 years were included in this study. Intraoperative gap and balance measurements and postoperative radiographic evaluation were performed. A total arc of range of motion was achieved up to 98% of preoperative values at 3 weeks postoperatively. Intraoperative gap and balance were stable throughout the entire range of motion. In addition, there were no statistically significant differences in either balance or gap values at each flexion angle. KA TKA is a “simple surgery” rather than a “challenging surgery” because additional soft tissue procedures are not required, operative time is short, intraoperative and postoperative balance is very stable, and a good alignment is achieved. This procedure may relieve surgeons of the stress of TKA for valgus deformities.
