scholarly journals Achieving a Balanced Knee in Robotic TKA

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 535
Author(s):  
Alexander C Gordon ◽  
Michael A Conditt ◽  
Matthias A Verstraete
Keyword(s):  
Soft Tissue ◽  
Real Time ◽  
Consecutive Series ◽  
Component Position ◽  
Coronal Alignment ◽  
Robotic Assisted ◽  
Primary Tkas ◽  
Wide Range ◽  
Total Knee ◽  
Surgical Corrections

Total knee arthroplasty (TKA) surgery with manual instruments provides a quantitatively balanced knee in approximately 50% of cases. This study examined the effect of combining robotics technology with real-time intra-operative sensor feedback on the number of quantitatively balanced cases in a consecutive series of 200 robotic-assisted primary TKAs. The robotics platform was used to plan the implant component position using correctable poses in extension and a manual, centrally pivoting the balancer in flexion, prior to committing to the femoral cuts. During the initial trialing, the quantitative state of balance was assessed using an instrumented tibial tray that measured the intra-articular loads in the medial and lateral compartments. These sensor readings informed a number of surgical corrections, including bone recuts, soft-tissue corrections, and cement adjustments. During initial trialing, a quantitatively balanced knee was achieved in only 65% of cases. After performing the relevant soft-tissue corrections, bone recuts, and cement adjustments, 87% of cases ended balanced through the range of motion. Meanwhile, this resulted in a wide range of coronal alignment conditions, ranging from 6° valgus to 9° varus. It is therefore concluded that gaps derived from robotics navigation are not indicative for a quantitatively balanced knee, which was only consistently achieved when combining the robotics platform with real-time feedback from intra-operative load sensors.

scholarly journals True Kinematic Alignment Is Applicable in 44% of Patients Applying Restrictive Indication Criteria—A Retrospective Analysis of 111 TKA Using Robotic Assistance

2021 ◽  
Vol 11 (7) ◽  
pp. 662
Author(s):  
Kim Huber ◽  
Bernhard Christen ◽  
Sarah Calliess ◽  
Tilman Calliess
Keyword(s):  
Soft Tissue ◽  
Retrospective Analysis ◽  
Patient Specific ◽  
Kinematic Alignment ◽  
Postoperative Phase ◽  
Robotic Assistance ◽  
Component Position ◽  
Joint Stability ◽  
Robotic Assisted ◽  
Primary Tkas

Introduction: Image-based robotic assistance appears to be a promising tool for individualizing alignment in total knee arthroplasty (TKA). The patient-specific model of the knee enables a preoperative 3D planning of component position. Adjustments to the individual soft-tissue situation can be done intraoperatively. Based on this, we have established a standardized workflow to implement the idea of kinematic alignment (KA) for robotic-assisted TKA. In addition, we have defined limits for its use. If these limits are reached, we switch to a restricted KA (rKA). The aim of the study was to evaluate (1) in what percentage of patients a true KA or an rKA is applicable, (2) whether there were differences regarding knee phenotypes, and (3) what the differences of philosophies in terms of component position, joint stability, and early patient outcome were. Methods: The study included a retrospective analysis of 111 robotic-assisted primary TKAs. Based on preoperative long leg standing radiographs, the patients were categorized into a varus, valgus, or neutral subgroup. Initially, all patients were planned for KA TKA. When the defined safe zone had been exceeded, adjustments to an rKA were made. Intraoperatively, the alignment of the components and joint gaps were recorded by robotic software. Results and conclusion: With our indication for TKA and the defined boundaries, “only” 44% of the patients were suitable for a true KA with no adjustments or soft tissue releases. In the varus group, it was about 70%, whereas it was 0% in the valgus group and 25% in the neutral alignment group. Thus, significant differences with regard to knee morphotypes were evident. In the KA group, a more physiological knee balance reconstructing the trapezoidal flexion gap (+2 mm on average laterally) was seen as well as a closer reconstruction of the surface anatomy and joint line in all dimensions compared to rKA. This resulted in a higher improvement in the collected outcome scores in favor of KA in the very early postoperative phase.

scholarly journals How to Quantitatively Balance a Total Knee? A Surgical Algorithm to Assure Balance and Control Alignment

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 700
Author(s):  
Ryan E. Moore ◽  
Michael A. Conditt ◽  
Martin W. Roche ◽  
Matthias A. Verstraete
Keyword(s):  
Soft Tissue ◽  
Surgical Navigation ◽  
Surgical Correction ◽  
Patient Specific ◽  
Popliteus Tendon ◽  
Limb Alignment ◽  
Coronal Alignment ◽  
Total Knee ◽  
The Impact ◽  
Surgical Corrections

To achieve a balanced total knee, various surgical corrections can be performed, while intra-operative sensors and surgical navigation provide quantitative, patient-specific feedback. To understand the impact of these corrections, this paper evaluates the quantitative impact of both soft tissue releases and bone recuts on knee balance and overall limb alignment. This was achieved by statistically analyzing the alignment and load readings before and after each surgical correction performed on 479 consecutive primary total knees. An average of three surgical corrections were required following the initial bone cuts to achieve a well aligned, balanced total knee. Various surgical corrections, such as an arcuate release or increasing the tibial polyethylene insert thickness, significantly affected the maximum terminal extension. The coronal alignment was significantly impacted by pie-crusting the MCL, adding varus to the tibia, or releasing the arcuate ligament or popliteus tendon. Each surgical correction also had a specific impact on the intra-articular loads in flexion and/or extension. A surgical algorithm is presented that helps achieve a well-balanced knee while maintaining the sagittal and coronal alignment within the desired boundaries. This analysis additionally indicated the significant effect that soft tissue adjustments can have on the limb alignment in both anatomical planes.

scholarly journals Patient-Reported Outcomes with Tibial Baseplate Position and PCL Status in Conforming Total Knee Arthroplast

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Joseph A. Madden, BS ◽  
Payton K. Arnold, MS ◽  
Evan R. Deckard, BSE ◽  
R. Michael Meneghini, MD
Keyword(s):  
Tibial Slope ◽  
Activity Level ◽  
Posterior Tibial Slope ◽  
Consecutive Series ◽  
Posterior Tibial ◽  
Primary Tkas ◽  
Measurement Protocol ◽  
Patient Reported ◽  
Total Knee ◽  
Climbing Stairs

Background and Hypothesis: Anteroposterior (AP) tibial baseplate position, posterior tibial slope, and posterior cruciate ligament (PCL) status in total knee arthroplasty (TKA) undoubtedly affect kinematic patterns. Further, few studies document patient-reported outcome measures (PROMS) in conforming polyethylene TKA with these varying parameters. The purpose of this study was to correlate PROMS with the interaction of AP tibial baseplate position, tibial slope, and PCL status in a consecutive series of primary TKAs with conforming polyethylene. We hypothesized that pain, function, and satisfaction may correlate with a combination of these three parameters. Experimental Design or Project Methods: 589 consecutive primary TKAs of a single implant design performed by a single surgeon between January 2016 and October 2018 were retrospectively reviewed. AP tibial baseplate position (relative to the middle of the tibial canal) and posterior tibial slope measurements were performed on 4-week postoperative sagittal view radiographs with a standardized measurement protocol by two independent blinded raters. Validated PROMS related to activity level, pain, and function were evaluated at minimum one-year. Results: Analyses indicated differences based on ≥8mm vs. <8mm of posterior distance of the tibial baseplate from the tibial canal and whether or not the PCL was released. Four analysis groups (PCL-preserved <8mm, PCL-preserved ≥8mm, PCL-resected <8mm, and PCL-resected ≥8mm) did not differ by demographics/covariates (p≥0.150), tibial slope (p≥0.132), or preoperative PROMS (p≥0.088). The PCL-released <8mm group achieved clinically meaningful higher absolute (92.0) and delta (42.0) median KOOS Jr. scores, higher satisfaction (96.3%), and the greatest reduction in pain while climbing stairs (-7.0) although some findings lacked statistical significance. Conclusion and Potential Impact: In conforming polyethylene TKAs, releasing the PCL in combination with AP tibial baseplate placement <8mm from the tibial canal may eliminate kinematic conflict between the PCL and tibial baseplate leading to improved satisfaction, function, and pain while climbing stairs.

scholarly journals Less iatrogenic soft-tissue damage utilizing robotic-assisted total knee arthroplasty when compared with a manual approach

2019 ◽  
Vol 8 (10) ◽  
pp. 495-501 ◽  
Author(s):  
Emily L. Hampp ◽  
Nipun Sodhi ◽  
Laura Scholl ◽  
Matthew E. Deren ◽  
Zachary Yenna ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Tissue Damage ◽  
Soft Tissues ◽  
Soft Tissue Damage ◽  
Anatomical Structures ◽  
Cruciate Retaining ◽  
Robotic Assisted ◽  
Total Knee

Objectives The use of the haptically bounded saw blades in robotic-assisted total knee arthroplasty (RTKA) can potentially help to limit surrounding soft-tissue injuries. However, there are limited data characterizing these injuries for cruciate-retaining (CR) TKA with the use of this technique. The objective of this cadaver study was to compare the extent of soft-tissue damage sustained through a robotic-assisted, haptically guided TKA (RATKA) versus a manual TKA (MTKA) approach. Methods A total of 12 fresh-frozen pelvis-to-toe cadaver specimens were included. Four surgeons each prepared three RATKA and three MTKA specimens for cruciate-retaining TKAs. A RATKA was performed on one knee and a MTKA on the other. Postoperatively, two additional surgeons assessed and graded damage to 14 key anatomical structures in a blinded manner. Kruskal–Wallis hypothesis tests were performed to assess statistical differences in soft-tissue damage between RATKA and MTKA cases. Results Significantly less damage occurred to the PCLs in the RATKA versus the MTKA specimens (p < 0.001). RATKA specimens had non-significantly less damage to the deep medial collateral ligaments (p = 0.149), iliotibial bands (p = 0.580), poplitei (p = 0.248), and patellar ligaments (p = 0.317). The remaining anatomical structures had minimal soft-tissue damage in all MTKA and RATKA specimens. Conclusion The results of this study indicate that less soft-tissue damage may occur when utilizing RATKA compared with MTKA. These findings are likely due to the enhanced preoperative planning with the robotic software, the real-time intraoperative feedback, and the haptically bounded saw blade, all of which may help protect the surrounding soft tissues and ligaments. Cite this article: Bone Joint Res 2019;8:495–501. DOI: 10.1302/2046-3758.810.BJR-2019-0129.R1.

Extramedullary Guide Alignment Is not Affected by Obesity in Primary Total Knee Arthroplasty

2020 ◽  
Author(s):  
Jocelyn Compton ◽  
Jessell Owens ◽  
Jesse Otero ◽  
Nicolas Noiseux ◽  
Timothy Brown
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Tibial Component ◽  
Primary Total Knee Arthroplasty ◽  
Coronal Plane ◽  
Coronal Alignment ◽  
Primary Tkas ◽  
Significant Difference ◽  
Total Knee ◽  
Valgus Alignment

AbstractCoronal alignment of the tibial implant correlates with survivorship of total knee arthroplasty (TKA), especially in obese patients. The purpose of this study was to determine if obesity affects coronal plane alignment of the tibial component when utilizing standard extramedullary tibial guide instrumentation during primary TKA. A retrospective review from June 2017 to February 2018 identified 142 patients (162 primary TKAs). There were 88 patients (100 knees) with body mass index (BMI) < 35 kg/m2 and 54 patients (62 knees) with BMI ≥ 35.0 kg/m2. The cohorts did not differ in age (p = 0.37), gender (p = 0.61), or Charlson's comorbidity index (p = 0.54). Four independent reviewers measured the angle between the base of the tibial component and the mechanical axis of the tibia on the anteroposterior view of long-leg film at first postoperative clinic visit. Outliers were defined as patients with greater than 5 degrees of varus or valgus alignment (n = 0). Reoperations and complications were recorded to 90 days postoperatively. There was no significant difference in mean tibial coronal alignment between the two groups (control alignment 90.8 ± 1.2 degree versus obese alignment 90.8 ± 1.2 degree, p = 0.91). There was no difference in varus versus valgus alignment (p = 0.19). There was no difference in the number of outliers (two in each group, p = 0.73). There was no difference in rate of reoperation (p = 1.0) or complication (p = 0.51). Obesity did not affect coronal plane alignment of the tibial component when using an extramedullary guide during primary TKA in our population.

Functional Outcomes and Accuracy of Patient-Specific Instruments for Total Knee Arthroplasty

2018 ◽  
Vol 25 (5) ◽  
pp. 470-475 ◽  
Author(s):  
Andrea H. Stone ◽  
Udai S. Sibia ◽  
James H. MacDonald
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Functional Outcomes ◽  
Patient Specific ◽  
Consecutive Series ◽  
Coronal Alignment ◽  
Patient Specific Instrumentation ◽  
Estimated Blood Loss ◽  
Patient Specific Instruments ◽  
Total Knee

Background. Patient-specific instruments (PSIs) were developed to improve mechanical axis alignment for patients undergoing total knee arthroplasty (TKA) as neutral alignment (180°) is a predictor of long-term success. This study examines alignment accuracy and functional outcomes of PSI as compared with standard instruments (SIs). Methods. We retrospectively reviewed a consecutive series of TKA procedures using PSI. A total of 85 PSI procedures were identified, and these were compared with a matched cohort of 85 TKAs using SI. Intraoperative decision-making, estimated blood loss, efficiency, Knee Society Scores, and postoperative radiographs were evaluated. Results. One hundred and seventy patients with comparable patient demographics were reviewed. Eighty-one percent of the PSI procedures were within target (180 ± 3°) mechanical alignment, while the SI group had 70% of cases within the target plane ( P = .132). Mean target alignment (2.0° PSI vs 2.2° SI, P = .477) was similar between groups. Twenty-seven percent of patients in the PSI group had surgeon-directed intraoperative recuts to improve the perceived coronal alignment. The change in hematocrit was reduced in the PSI group (8.89 vs 7.21, P = .000). Procedure time and total operating room time were equivalent. Knee Society Scores did not differ between groups at 6 months or at 1 year. Conclusion. Patient-specific instrumentation decreased change in hematocrit, though coronal alignment and efficiency were equivalent between groups. Surgeons must evaluate cuts intraoperatively to confirm alignment. Functional outcomes are equivalent for PSI and SI groups.

Highly Satisfied Total Knee Arthroplasty Patients Display a Wide Range of Soft Tissue Balance

2019 ◽  
Vol 33 (03) ◽  
pp. 247-254 ◽  
Author(s):  
Michael J. McAuliffe ◽  
Patrick B. O'Connor ◽  
Lisa J. Major ◽  
Gautam Garg ◽  
Sarah L. Whitehouse ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Individual Variability ◽  
Measured Parameter ◽  
Computer Assisted ◽  
Maximum Extension ◽  
Wide Range ◽  
Coronal Laxity ◽  
Total Knee

AbstractSoft tissue balancing while crucial for a successful total knee arthroplasty (TKA) is incompletely defined and the subject of broad recommendations. We analyzed 69 unilateral computer-assisted surgery posterior stabilized (PS) TKA subjects who postoperatively scored ≥36 out of a possible 40 points on the satisfaction section of the American Knee Society score (2011). We examined a range of postoperative coronal plane laxity parameters and the correlation between preoperative and postoperative laxity. Total postoperative coronal laxity arcs at maximum extension and 20 degrees of flexion varied between 2 and 12 and 3 and 13 degrees, respectively. Depending on the position of measurement, medial laxity was between 0.5 and 9.5 degrees and lateral laxity between 1 and 12 degrees. The change in laxity between maximum extension and 90 degrees of flexion demonstrated a range of 7 degrees medially and 12 degrees laterally. The total coronal arc of movement did not affect functional outcomes. A moderate correlation of 0.452 and 0.424 was seen between initial and postoperative total coronal laxity arcs in maximum extension and 20 degrees of flexion, respectively. The individual variability for each measured parameter within our cohort demonstrates TKA satisfaction is not as simple as producing a narrow range of coronal laxity parameters and that as with many body systems considerable variation is still consistent with excellent function. Our findings help to define acceptable balance parameters for PS TKA. It does not appear necessary to closely match postoperative laxity to that present preoperatively.

Effect of Tibial Slope on Coronal Alignment in Total Knee Arthroplasty

2021 ◽  
Author(s):  
Christopher J. Betzle ◽  
Kariline E. Bringe ◽  
John V. Horberg ◽  
Joseph T. Moskal ◽  
John W. Mann
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Computer Navigation ◽  
Tibial Slope ◽  
Consecutive Series ◽  
Coronal Alignment ◽  
Posterior Tibial ◽  
Average Change ◽  
Tibial Cut ◽  
Total Knee

AbstractMalalignment of total knee arthroplasty (TKA) components affects function and survivorship. Common practice is to set coronal alignment prior to adjusting slope. With improper jig placement, adjustment of the slope may alter coronal alignment. The purpose of this study was to quantify the change in coronal alignment with increasing posterior tibial slope while comparing two methods of jig fixation. A prospective consecutive series of 100 patients underwent TKA using computer navigation. Fifty patients had the extramedullary cutting jig secured proximally with one pin and 50 patients had the jig secured proximally with two pins. Coronal alignment (CA) was recorded with each increasing degree of posterior slope (PS) from 0 to 7 degrees. Mean CA and change in CA were compared between cohorts. Utilizing one pin, osteotomies drifted into varus with an average change in CA of 0.34 degrees per degree PS. At 4 degrees PS, patients started to have >3 degrees of varus with 12.0% having >3 degrees of varus at 7 degrees PS. Utilizing two pins, osteotomies drifted into valgus with an average change of 0.04 degrees in CA per degree PS. No patients in the two-pin cohort fell outside 3 degrees varus/valgus CA. CA was significantly different at all degrees of PS between the cohorts. Changes in PS influenced CA making verification of tibial cut intraoperative critical. Use of >1 pin and computer navigation were beneficial to prevent coronal plane malalignment. This relationship may explain why computer navigation has been shown to improve alignment as well as survivorship and outcomes in some patients, especially those <65 years.

Balancing of total knee arthroplasty by bone cuts achieves accurately balanced soft tissues without the need for soft tissue releases

2018 ◽  
Vol 3 (5) ◽  
pp. 263-268 ◽  
Author(s):  
Ponky Firer ◽  
Brad Gelbart
Keyword(s):  
Total Knee Arthroplasty ◽  
Patient Satisfaction ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Soft Tissues ◽  
Size Difference ◽  
Gap Size ◽  
X Rays ◽  
Coronal Alignment ◽  
Total Knee

IntroductionPatient satisfaction, after mechanically aligned Total Knee Arthroplasty (TKA) is only 80%-85%. There is an inabilty to consistently get perfect soft tissue balance with this technique. It is postulated that soft tissue balance within 2° can be achieved by the boney cuts (Bone Balancing) without soft tissue releases, accepting whatever coronal mechanical alignment (CMA) this produces; that the alignment produced would be similar to natural (constitutional) alignment and that balanced knees would improve patient satisfaction.MethodsWe report on 914 consecutive TKAs using Bone Balancing: the femoral rotation for the flexion gap; the distal femoral cut and valgus angle for the extension gap are adjusted to give equal gap sizes with soft tissue balanced within 2° of medio-lateral laxity. Long leg X-rays were used to measure post-operative coronal alignment. Satisfaction beyond 1 year post operation was assessed by an independent researcher, using a question on satisfaction and a VAS score.Results782(85.5%) TKAs with satisfactory x-rays were available at 2-7 years follow up. Their CMA had a similar distribution profile to reported natural alignment studies. Of these, 672 (86%) had a CMA of 0°±3° (’aligned' group). Overall patient satisfaction was 92.8%, with satisfied patients having a mean (range) VAS score of 9.53 (7.3-10.0) and the dissatisfied patients 3.78 (0.0-6.3) (p<0.0001). There was no difference in satisfaction between ’aligned' knees (92.7%) and those ’outliers', whose CMA was >±3° (93.6%) (p=0.853). All balance measurements were within 3° with 92.2% being ≤2°. Gap size difference between extension and 90° flexion was ≤2mm in 98.7% of cases. Midflexion (45° flexion) balance was within 3° in all cases and the gap size difference was ≤2mm in 89%.ConclusionBalancing by bone cuts is able to achieve accurately balanced soft tissues without the need for soft tissue releases. The coronal alignment profile produced matches that of the normal population. This technique improves satisfaction compared to the literature for mechanically aligned TKAs. Acurate and measured soft tissue balancing needs further consideration in TKAs.Level of EvidenceLevel IV.

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