Alignment in total knee arthroplasty

2020 ◽  
Vol 102-B (3) ◽  
pp. 276-279 ◽  
Author(s):  
Sam Oussedik ◽  
Matthew P. Abdel ◽  
Jan Victor ◽  
Mark W. Pagnano ◽  
Fares S. Haddad
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Kinematic Alignment ◽  
Hybrid Technique ◽  
Soft Tissue Envelope ◽  
The Past ◽  
Robotic Assisted Surgery ◽  
Total Knee ◽  
Implant Alignment

Dissatisfaction following total knee arthroplasty is a well-documented phenomenon. Although many factors have been implicated, including modifiable and nonmodifiable patient factors, emphasis over the past decade has been on implant alignment and stability as both a cause of, and a solution to, this problem. Several alignment targets have evolved with a proliferation of techniques following the introduction of computer and robotic-assisted surgery. Mechanical alignment targets may achieve mechanically-sound alignment while ignoring the soft tissue envelope; kinematic alignment respects the soft tissue envelope while ignoring the mechanical environment. Functional alignment is proposed as a hybrid technique to allow mechanically-sound, soft tissue-friendly alignment targets to be identified and achieved. Cite this article: Bone Joint J 2020;102-B(3):276–279.

scholarly journals What is a balanced knee replacement?

2018 ◽  
Vol 3 (12) ◽  
pp. 614-619 ◽  
Author(s):  
Lucy C. Walker ◽  
Nick D. Clement ◽  
Kanishka M. Ghosh ◽  
David J. Deehan
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Replacement ◽  
Knee Arthroplasty ◽  
Current Evidence ◽  
Soft Tissue Envelope ◽  
Total Knee ◽  
Uneven Wear ◽  
Definition Of ◽  
Revision Tka

For multifactorial reasons an estimated 20% of patients remain unsatisfied after total knee arthroplasty (TKA). Appropriate tension of the soft tissue envelope encompassing the knee is important in total knee arthroplasty and soft tissue imbalance contributes to several of the foremost reasons for revision TKA, including instability, stiffness and aseptic loosening. There is debate in the literature surrounding the optimum way to achieve balancing of a total knee arthroplasty and there is also a lack of an accepted definition of what a balanced knee replacement is. It may be intuitive to use the native knee as a model for balancing; however, there are many difficulties with translating this into a successful prosthesis. One of the foundations of TKA, as described by Insall, was that although the native knee has more weight transmitted through the medial compartment this was to be avoided in a TKA as it would lead to uneven wear and early failure. There is a focus on achieving symmetrical tension and pressure and subsequent ‘balance’ in TKA, but the evidence from cadaveric studies is that the native knee is not symmetrically balanced. As we are currently trying to design an implant that is not based on its anatomical counterpart, is it possible to create a truly balanced prosthesis or to even to define what that balance is? The authors have reviewed the current evidence surrounding TKA balancing and its relationship with the native knee. Cite this article: EFORT Open Rev 2018;3:614-619. DOI: 10.1302/2058-5241.3.180008.

scholarly journals Personalized alignment in total knee arthroplasty: current concepts

SICOT-J ◽  
2021 ◽  
Vol 7 ◽  
pp. 19
Author(s):  
Sébastien Lustig ◽  
Elliot Sappey-Marinier ◽  
Camdon Fary ◽  
Elvire Servien ◽  
Sébastien Parratte ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Functional Outcomes ◽  
Inverse Kinematic ◽  
Joint Line ◽  
Kinematic Alignment ◽  
Joint Line Obliquity ◽  
Total Knee ◽  
Neutral Alignment

Traditionally in total knee arthroplasty (TKA), a post-operative neutral alignment was the gold standard. This principle has been contested as functional outcomes were found to be inconsistent. Analysis of limb alignment in the non-osteoarthritic population reveals variations from neutral alignment and consideration of a personalized or patient-specific alignment in TKA is challenging previous concepts. The aim of this review was to clarify the variations of current personalized alignments and to report their results. Current personalized approaches of alignment reported are: kinematic, inverse kinematic, restricted kinematic, and functional. The principle of “kinematic alignment” is knee resurfacing with restitution of pre-arthritic anatomy. The aim is to resurface the femur maintaining the native femoral joint line obliquity. The flexion and extension gaps are balanced with the tibial resection. The principle of the “inverse kinematic alignment” is to resurface the tibia with similar medial and lateral bone resections in order to keep the native tibial joint line obliquity. Gap balancing is performed by adjusting the femoral resections. To avoid reproducing extreme anatomical alignments there is “restricted kinematic alignment” which is a compromise between mechanical alignment and true kinematic alignment with a defined safe zone of alignment. Finally, there is the concept of “functional alignment” which is an evolution of kinematic alignment as enabling technology has progressed. This is obtained by manipulating alignment, bone resections, soft tissue releases, and/or implant positioning with a robotic-assisted system to optimize TKA function for a patient’s specific alignment, bone morphology, and soft tissue envelope. The aim of personalizing alignment is to restore native knee kinematics and improve functional outcomes after TKA. A long-term follow-up remains crucial to assess both outcomes and implant survivorship of these current concepts.

Functional alignment achieves soft tissue balance in total knee arthroplasty as measured with quantitative sensor-guided technology

2021 ◽  
pp. 1-8
Author(s):  
Justin S. Chang ◽  
Babar Kayani ◽  
Charles Wallace ◽  
Fares S. Haddad
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Knee Flexion ◽  
Lateral Compartment ◽  
Soft Tissue Balance ◽  
Sensor Technology ◽  
Soft Tissue Envelope ◽  
Total Knee ◽  
Compartment Pressures

Aims Total knee arthroplasty (TKA) using functional alignment aims to implant the components with minimal compromise of the soft-tissue envelope by restoring the plane and obliquity of the non-arthritic joint. The objective of this study was to determine the effect of TKA with functional alignment on mediolateral soft tissue balance as assessed using intraoperative sensor-guided technology. Methods This prospective study included 30 consecutive patients undergoing robotic-assisted TKA using the Stryker PS Triathlon implant with functional alignment. Intraoperative soft tissue balance was assessed using sensor-guided technology after definitive component implantation; soft tissue balance was defined as intercompartmental pressure difference (ICPD) of < 15 psi. Medial and lateral compartment pressures were recorded at 10°, 45°, and 90° of knee flexion. This study included 18 females (60%) and 12 males (40%) with a mean age of 65.2 years (SD 9.3). Mean preoperative hip-knee-ankle deformity was 6.3° varus (SD 2.7°). Results TKA with functional alignment achieved balanced medial and lateral compartment pressures at 10° (25.0 psi (SD 6.1) vs 23.1 psi (SD 6.7), respectively; p = 0.140), 45° (21.4 psi (SD 5.9) vs 20.6 psi (SD 5.9), respectively; p = 0.510), and 90° (21.2 psi (SD 7.1) vs 21.6 psi (SD 9.0), respectively; p = 0.800) of knee flexion. Mean ICPD was 6.1 psi (SD 4.5; 0 to 14) at 10°, 5.4 psi (SD 3.9; 0 to 12) at 45°, and 4.9 psi (SD 4.45; 0 to 15) at 90° of knee flexion. Mean postoperative limb alignment was 2.2° varus (SD 1.0°). Conclusion TKA using the functional alignment achieves balanced mediolateral soft tissue tension through the arc of knee flexion as assessed using intraoperative pressure-sensor technology. Further clinical trials are required to determine if TKA with functional alignment translates to improvements in patient satisfaction and outcomes compared to conventional alignment techniques.

scholarly journals Clinical outcomes of kinematic alignment versus mechanical alignment in total knee arthroplasty: a systematic review

2020 ◽  
Vol 5 (8) ◽  
pp. 486-497
Author(s):  
Mark Anthony Roussot ◽  
Georges Frederic Vles ◽  
Sam Oussedik
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Clinical Outcomes ◽  
Knee Arthroplasty ◽  
Soft Tissue Balance ◽  
Kinematic Alignment ◽  
Mechanical Alignment ◽  
Patient Reported ◽  
Total Knee ◽  
Alignment Strategy

Although mechanical alignment (MA) has traditionally been considered the gold standard, the optimal alignment strategy for total knee arthroplasty (TKA) is still debated. Kinematic alignment (KA) aims to restore native alignment by respecting the three axes of rotation of the knee and thereby producing knee motion more akin to the native knee. Designer surgeon case series and case control studies have demonstrated excellent subjective and objective clinical outcomes as well as survivorship for KA TKA with up to 10 years follow up, but these results have not been reproduced in high-quality randomized clinical trials. Gait analyses have demonstrated differences in parameters such as knee adduction, extension and external rotation moments, the relevance of which needs further evaluation. Objective improvements in soft tissue balance using KA have not been shown to result in improvements in patient-reported outcomes measures. Technologies that permit accurate reproduction of implant positioning and objective measurement of soft tissue balance, such as robotic-assisted TKA and compartmental pressure sensors, may play an important role in improving our understanding of the optimum alignment strategy and implant position. Cite this article: EFORT Open Rev 2020;5:486-497. DOI: 10.1302/2058-5241.5.190093

scholarly journals Kinematic alignment is bone and soft tissue preserving compared to mechanical alignment in total knee arthroplasty

The Knee ◽  
2019 ◽  
Vol 26 (2) ◽  
pp. 466-476 ◽  
Author(s):  
Vincent V.G. An ◽  
Joshua Twiggs ◽  
Murilo Leie ◽  
Brett A. Fritsch
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Kinematic Alignment ◽  
Mechanical Alignment ◽  
Total Knee

scholarly journals Soft Tissue Envelope Preserving Technique for Computer Navigated Total Knee Arthroplasty

2017 ◽  
Vol 5 (5_suppl5) ◽  
pp. 2325967117S0015
Author(s):  
Gavin Clark ◽  
Luke Mooney
Keyword(s):  
Total Knee Arthroplasty ◽  
Patient Satisfaction ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Mechanical Axis ◽  
Computer Navigation ◽  
Clinical Results ◽  
Short Term ◽  
Soft Tissue Envelope ◽  
Total Knee

Objectives: Current techniques in Total Knee Arthroplasty(TKA) are utilitarian in that all patients are recommended to have the same alignment of neutral mechanical axis. It has been well established that the population has a varied natural alignment with less than 20% of patients naturally neutral. The ability to predictably individualise alignment for patients is hypothesised to result in greater patient satisfaction. This technique aims to modify mechanical axis technique to consider an individual’s soft tissue constraints. Methods: Soft Tissue Envelope Preserving (STEP) is an operative technique for performing TKA that utilises the soft tissue data obtained intra-operatively from computer navigation registration to determine the optimal alignment to provide balanced positioning of implants without the need for soft tissue releases. Hence balance is achieved through bone cuts rather than altering the patient’s soft tissue balance. The technique will be described in detail. Results: The last 100 patients performed with complete data sets including navigation files and both pre-op and one year post operative outcome measures were reviewed. The spread of overall alignments and bony resections have been compiled with no outliers outside 5 degrees of neutral. The clinical results were comparable with other series and patient satisfaction of greater than 90% was reported. There were no MCL or LCL releases performed. Ilio-tibial band partial releases were the only reported soft tissue releases made. Conclusions: This technique is a safe and effective method of performing TKA with good short term outcomes. It minimises the use of soft tissue releases by utilising the patient’s own soft tissue envelope to balance the knee whilst maintaining the basic principles of a measured resection mechanical axis technique. It has resulted in excellent patient satisfaction in the short term.

scholarly journals Robotic Arm Assisted Total Knee Arthroplasty: Addressing 1-12 Degrees Valgus Knees

10.29007/wrvx ◽  
2019 ◽  
Author(s):  
Jingwei Zhang ◽  
Manoshi Bhowmik-Stoker ◽  
Laura Scholl ◽  
Caitlin Condrey ◽  
Kevin Marchand ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Robotic Arm ◽  
Womac Pain ◽  
Case Review ◽  
Retrospective Case ◽  
Soft Tissue Envelope ◽  
Patient Reported ◽  
Total Knee

The purpose of this work was to determine the number of soft tissue releases and component orientation of valgus cases performed with Robotic-Arm Assisted total knee arthroplasty (RATKA).This study was a retrospective chart review of cases performed by a single surgeon from July 2016 to December 2017. 72 RATKA cases were defined as having a valgus deformity pre-operatively. Patient demographics and intraoperative surgical details were collected, including initial and final 3D component alignment, knee balancing gaps, full or partial releases. Post- operatively, radiographs, adverse events, and reduced WOMAC pain and KOOS Jr scores were collected at 6 months post-operatively.Pre-operatively, knee deformities ranged from 1o to 12° with fixed flexion contracture. All knees were corrected within 2.5 degrees of mechanical neutral. Medial and lateral gaps were balanced in extension 100% of cases and flexion 93% of cases.Radiographic evidence suggested well seated and well-fixed components. No revision and re- operation is reported. Patient reported outcomes measures collected at 6-month follow up indicated an improvement in WOMAC pain score from 9.6 to 3.2 and improvement in KOOS Jr from 44.7 to 74.4 points.In this retrospective case review, soft tissue releases were not needed to address valgus knees ranging from 1-12° of deformity. The surgeon was able to balance the knee with bone resections and avoid disturbing the soft tissue envelope. While this study has a number of limitations, RATKA for valgus knees should continue to be investigated in a multicenter study.

Periarticular Soft Tissue Envelope Size and Postoperative Wound Complications Following Total Knee Arthroplasty

2018 ◽  
Vol 33 (7) ◽  
pp. S249-S252 ◽  
Author(s):  
Stephen Yu ◽  
Matthew Siow ◽  
Khalid Odeh ◽  
William J. Long ◽  
Ran Schwarzkopf ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Wound Complications ◽  
Postoperative Wound ◽  
Soft Tissue Envelope ◽  
Total Knee

scholarly journals After 25 years of computer-navigated total knee arthroplasty, where do we stand today?

Arthroplasty ◽  
2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Siddharth M. Shah
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Computer Navigation ◽  
Soft Tissue Release ◽  
Computer Assisted ◽  
Robotic Assisted ◽  
Total Knee ◽  
Implant Alignment ◽  
Navigated Tka

Abstract Background Limb and implant alignment along with soft tissue balance plays a vital role in the outcomes after total knee arthroplasty (TKA). Computer navigation for TKA was first introduced in 1997 with the aim of implanting the prosthetic components with accuracy and precision. This review discusses the technique, current status, and scientific evidence pertaining to computer-navigated TKA. Body The adoption of navigated TKA has slowly but steadily increased across the globe since its inception 25 years ago. It has been more rapid in some countries like Australia than others, like the UK. Contemporary, large console-based navigation systems help control almost every aspect of TKA, including the depth and orientation of femoral and tibial resections, soft-tissue release, and customization of femoral and tibial implant positions in order to obtain desired alignment and balance. Navigated TKA results in better limb and implant alignment and reduces outliers as compared to conventional TKA. However, controversy still exists over whether improved alignment provides superior function and longevity. Surgeons may also be hesitant to adopt this technology due to the associated learning curve, slightly increased surgical time, fear of pin site complications, and the initial set-up cost. Furthermore, the recent advent of robotic-assisted TKA which provides benefits like precision in bone resections and avoiding soft-tissue damage due to uncontrolled sawing, in addition to those of computer navigation, might be responsible for the latter technology taking a backseat. Conclusion This review summarizes the current state of computer-navigated TKA. The superiority of computer navigation to conventional TKA in improving accuracy is well established. Robotic-assisted TKA provides enhanced functionality as compared to computer navigation but is significantly more expensive. Whether robotic-assisted TKA offers any substantive advantages over navigation is yet to be conclusively proven. Irrespective of the form, the use of computer-assisted TKA is on the rise worldwide and is here to stay.

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