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Incidence of soft tissue releases in robotic assisted cementless TKA with mechanical alignment and flexion gap balancing

Incidence of soft tissue releases in robotic assisted cementless TKA with mechanical alignment... Background To ensure the success of total knee arthroplasty ( TKA), precise bone cuts and a well-balanced soft tissue envelope are crucial. Soft tissue release may be necessary, subject to various factors. Therefore, documenting the type, frequency, and necessity of soft tissue releases can establish a benchmark for comparing different alignment tech- niques and philosophies and evaluating their outcomes. The purpose of this study was to demonstrate that robotic- assisted knee surgery requires minimal soft tissue release. Methods We prospectively documented and retrospectively reviewed the soft tissue releases employed in securing ligament balance in the first 175 patients who received robotic-assisted TKAs at Nepean Hospital. ROSA was utilized in all surgeries with the aim of restoring mechanical coronal alignment, with a flexion gap balancing technique. Surgeries were performed between December 2019 to August 2021 by a single surgeon who used a standard medial parapatellar approach without a tourniquet, and the cementless persona prosthesis. All patients were followed up for a minimum of 6 months post-surgery. Soft tissue releases included any form of medial release for varus knee, postero- lateral release for valgus knee and PCL fenestration or sacrifice. Results There were 131 female and 44 male patients, aged between 48 to 89 years (average 60 years). The preopera- tive HKA ranged from 22 degrees varus to 28 degrees valgus, with 71% of patients presenting with a varus deformity. For the whole group, the no need for soft tissue release was documented in 123 patients (70.3%), small fenestrated releases of PCL in 27 (15.4%), sacrifice of PCL in 8 (4.5%), medial releases in 4 (2.3%) and posterolateral releases in 13 (7.4%). In 29.7% of patients in whom a soft tissue release was necessary for balance, over half were/received minor fenestrations of the PCL. Outcomes to date included no revisions or impending revisions, 2 MUAs (1%), and Oxford knee scores averaged 40 at 6 months. Conclusion We concluded that Robot technology enhanced the precision of bone cuts and allowed for titration of required soft tissue releases to achieve optimal balance. Keywords Robotic-assisted total knee arthroplasty, TKA, ROSA, Mechanical alignment, Soft tissue release Introduction Robot-assist TKA allows for execution and validation of *Correspondence: higher precision of bone cuts [1]. It also makes it possi- Femi E. Ayeni femi.ayeni@sydney.edu.au ble to intraoperatively assess soft tissue balance objec- Department of Orthopaedics, Nepean Hospital, Derby Street, tively, which is critical to a ‘balanced and stable knee’. It is Kingswood, Penrith, NSW 2747, Australia important to achieve a balanced knee both clinically and Nepean Institute of Academic Surgery, Nepean Clinical School, The University of Sydney, 62 Derby St, Kingswood, NSW 2747, Australia in terms of robotic parameters. © The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/. Selvanathan et al. Arthroplasty (2023) 5:28 Page 2 of 7 Information obtained enables surgeons to gauge the outcome of knee balancing before and after bone resec- tion. Digital information prevents/avoids redundant bone cuts and soft tissue release. Moreover, from the ‘surgeon’s feel’ of a balanced knee, which has been demonstrated to be less than accurate, current technologies can allow for digital representation of soft tissue laxity and inform the required soft tissue releases to achieve balance. The com - bination of clinical assessment and digital parameters enables surgeons to evaluate and respond to the required actions needed to attain better balance. Managing a severe coronal plane knee deformity using conventional instrumentation may require significant soft tissue release, which may be compounded by relative inaccuracy of the tibial or femoral bone cuts, thereby car- rying a risk of over-release and instability [2]. Document- ing and analyzing the number and extent of soft tissue release with each technology and alignment philosophy may assist in working towards the most appropriate and Fig. 1 Standard surgical exposure prior to bone cuts reproducible technique to achieve balance with the least invasiveness and thereby improve patient outcomes fur- trackers were placed within the standard incision. The ther [3]. Thus, this study sought to investigate if minimal pre-cut balancing plan was made with the robot after soft to no soft tissue release is required in robotic-assisted tissue laxity was incorporated into the balance algorithm knees. and after assessment in terms of the range of motion with varus and valgus loading. Methods In all cases, the femoral and tibial bone cuts were We prospectively documented and retrospectively aligned perpendicular to the mechanical axis (0 degrees reviewed the soft tissue release required in securing liga- varus valgus). Balancing equation aimed to ensure at ment balance in the first 175 consecutive robot-assisted least 19 mm of joint space in the medial compartment for TKAs in our centre. The robotic surgical assistant ROSA a valgus deformity or the lateral compartment for a varus (Zimmer Biomet, Warsaw, IN, USA) was used in all sur- deformity. The opposite compartment was accepted geries, aiming for restoring mechanical alignment with whenever the tighter joint space was observed, as the HKA of 0 and a flexion gap balance by using the ligament surgeon was prepared to perform the required soft tis- tensioning “FuZion” device (Zimmer Biomet, Warsaw, sue releases to ensure balance after bone resection and IN, USA). Surgeries were performed between December removal of remaining osteophytes. 2019 to August 2021 by a single surgeon using a standard Once the proximal tibial and distal femoral cuts were medial parapatellar approach without a tourniquet. All made and validated, the remaining osteophytes were implants were cementless Persona TKA prosthesis (Zim- removed and the extension space assessed, with the mer Biomet, Warsaw, IN, USA) and all patients were fol- spacer block equivalent to 19 mm space. The aim was to lowed up for a minimum of 6  months post-surgery. Soft ensure sufficient space in one compartment to accommo - tissue releases took into account any form of medial side date the smallest spacer block and ensure that extension release for varus knee, posterolateral fenestrated release was between 0 and 10 degrees. If the medial compart- and/or lateral retinacular release for valgus knee and PCL ment was tight, then a posteromedial release would be fenestration or sacrifice. performed as needed to effect balance and fully accom - The standard surgical exposure suffices just to expose modate the spacer in both compartments. If the lateral the anterior aspect of the tibia to ensure juxtaposition compartment was tight, then a fenestrated posterolateral of the tibial cutting block of the robot arm. Any further capsular release plus or minus PCL sacrifice was done exposure of the anteromedial tibia subsequently was as needed to achieve balance and fully accommodate performed as a mean of posteromedial release. Figure  1 the spacer. These releases would be documented. The shows our standard surgical exposure without any soft FuZion device was then used to ensure a balanced flex - tissue release. ion space and was tensioned by using its ratchet system All large and accessible osteophytes were removed. It is in 95 degrees of flexion. The robot requires the knee to of note that in this group of patients the standard array S elvanathan et al. Arthroplasty (2023) 5:28 Page 3 of 7 be between 90 and 95 degrees of flexion at this point of Table 1 Results of soft tissue releases for varus knee tensioning to register the required rotation of the femo- Releases in Varus HKA < -20 (varus Total patients- 121 ral component to balance the flexion space. This rotation knee) of the femoral component was then incorporated into Types of soft tissue releases n Percentage the flexion balance algorithm, and final flexion balance Nil releases 86 71% was confirmed, ensuring at least 19  mm medial and lat - Fenestrated PCL 24 20% eral joint spaces in flexion. The final femoral 4 in 1 bone PCL Sacrificed 7 6% cuts were then performed, and the rotation of the femo- Medial releases 4 3% ral component was then confirmed to effect flexion gap balance independent of the transepicondylar or posterior condylar axes. The trial reduction is the final opportunity to ensure (Fig.  3). Included in this patient group requiring soft tis- balance is achieved and if further releases are required. sue releases were 4 patients that also needed a bone re- This is particularly relevant for sagittal balance and flex - cut (3 femurs, 1 tibia). In the remaining 171 patients, ion range. If required, the PCL may be fenestrated if their initial bone resections were validated by ROSA and any tibial lift off is observed. After the implantation of found to be within the 1.5  mm accuracy zone set by the true prosthesis, the final balance through the range was robot software. assessed and documented. The need for soft tissue releases was higher in patients presenting with valgus knee deformities (Table  2). In Data analysis and statistical analysis patients whose coronal deformity was greater than 2 We used descriptive statistics to report the incidence degrees varus or valgus, the soft tissue release rate was of each category of cases treated. All statistical analyses 29% in varus knees) against 53% in valgus knees. were performed by using Microsoft Excel (v.16.45). The patella was not resurfaced in 137 patients (78%) and a lateral release was required in 18 patients (10%). Results A lateral release was needed in 6 patients (4%) in those The subjects included 131 female and 44 male patients whose patella was not resurfaced. Four of the patients and were all within the age range from 48 to 89 (average receiving patella resurfacing required augmented tan- 60 years) years. The soft tissue releases were assessed as a talum patella due to severe patellofemoral arthritis. whole group and then in subgroups for varus deformity The tibial polyethylene inserts were cruciate retaining greater than 2 degrees and valgus deformity more than 2 CR in 131 patients (75%), medial congruent MC in 42 degrees. The preoperative HKA ranged from 22 degrees patients (24%), ultra-congruent UC in 1 patient and con- varus to 28 degrees valgus, with 71% of the patients pre- strained posterior stabilised CPS in 1 patient. Outcomes senting with a varus deformity (Fig. 2, Table 1). to date included no revisions or impending revisions, 2 For the whole group, no soft tissue release was required MUAs (1%), and Oxford knee scores that averaged 40 at in 123 patients (70.3%). In 52 patients (29.7%), some form 6 months. of soft tissue release was needed to ensure balance. The soft tissue releases performed included small fenestrated Discussion releases of PCL in 27 patients (15.4%), sacrifice of PCL Soft tissue releases are utilized ala carte and the current in 8 patients (4.5%), posteromedial releases in 4 patients use of the technique has the potential to optimize balance (2.3%) and posterolateral releases in 13 patients (7.4%) and outcomes. A study by Plascos et al. [1] reported that Fig. 2 Preoperative HKA deformity Selvanathan et al. Arthroplasty (2023) 5:28 Page 4 of 7 Fig. 3 Soft tissue releases performed Table 2 Result of soft tissue releases for valgus knees thereby facilitating early mobilization and discharge, with a significant reduction in the length of hospital stay. Releases in valgus HKA > 2° Total patients (n = 32) These early benefits of minimizing soft tissue releases (valgus knee) during TKA, however, did not translate to any long-term Types of soft tissue releases n Percentage benefits as there was no difference between groups at Nil releases 15 47% 2  years in terms of the Oxford knee score or forgotten Fenestrated PCL 3 9% knee score. PCL sacrifice 1 3% With the robot-assisted TKA, we could avoid unneces- Posterolateral releases 13 41% sary soft tissue release optimizing coronal alignment to the mechanical axis to achieve a balanced knee. However, as in study by Morcos et al. [5] and other reports, no dif- ference was identified in patient-reported outcomes after robotic-assisted gap-balancing required less soft tissue 1 year no matter minimal or extensive soft tissue releases release compared to robot-assisted measured resection were used in TKA. and conventional measured resection. In the study, 31% In our study, we considered small fenestrated releases out of 615 robotic-assisted gap balancing required one of PCL (Fig.  4) and PCL sacrifices for the soft tissue or more soft tissue releases. Similarly, our study reported release. The total percentage of patients in these sub - that 29.7% of the patients that had robotic TKA required groups was 19.9%. Some elected to sacrifice the PCL a soft tissue release. Clark et  al. [4] reported on the sig- routinely and substitute with a cam post PS (posterior nificant short-term benefits of robotic TKA as compared stabilizer) design or utilize an MC (medial congruent) with conventional TKA, as indicated by the decreased poly insert and, as a result, the actual rate of soft tissue need for soft tissue releases, in particular, improved releases required for correction in the coronal plane was range of motion and decreased pain scores on day 1 and only 9.7%. We believe that preserving the PCL provides a a reduction in narcotic use on day 2. Total reduction in leverage to retain, fenestrate, or remove to achieve better morphine-equivalent dosage was also significantly lower, balance of the knee in flexion and extension (Fig. 3). Fig. 4 Fenestrated PCL performed using a size 15 blade S elvanathan et al. Arthroplasty (2023) 5:28 Page 5 of 7 More patients with valgus knee deformity required Table 3 Rotation of femoral component from TEA (+ 3° = External rotation, -3° = Internal rotation) soft tissue release in comparison with patients with varus knee deformity (53% vs. 29%). Based on our sub- Degrees of rotation n Percentage analysis, we noted that a preoperative HKA greater 0 ± 3 123 74% than 12 degrees was more likely to require a soft tissue > + 3 30 18% release. For patients with a valgus deformity less than 6 < -3 14 8% degrees the release rate was 0%, for valgus between 6 to 12 degrees the release rate was 22% and for 12 degrees or more the rate of release needed to achieve balance was 67%. This value can serve as a predictor in future Firer et  al. reported that, in conventional instru- to determine the need for soft tissue releases if an MA mented TKA, no soft tissue releases were secured [7] philosophy is followed. Furthermore, we acknowledge when ligament balance was secured completely by some authors might consider the utilization of a lateral bone cuts and implant placement to accommodate the parapatellar approach in more severe valgus deformi- soft tissues. PCL was removed in all patients. Bone ties but for standardization across our cohort, we used cuts were made based on a template, depending on the the medial parapatellar approach in all patients regard- degree of deformity calculated from the pre-operative less of presenting deformity. There was no conversion X-ray by using a gap balancing technique for both flex - to higher constraint prosthesis in any of our patients ion and extension. However, no objective ligament bal- intraoperatively. ancing assessment was conducted intraoperatively due Lateral retinacular releases were performed if the to the debate on what is the appropriate value of ten- patella was not tracking centrally in the trochlear groove sion [7]. In this study, a balanced knee depended on the at final reduction and 10% of our patients required lateral ‘surgeons feel factor’ or ‘Surgeon-defined Assessment’ retinacular release, and 4% were from the non-resurfaced (SDA). MacDessi et  al., in their paper, concluded that group. The effect of TKA component positioning could SDA was a poor measure of soft tissue assessment in contribute to patella mal-tracking [6]. We routinely per- TKA [8]. form CT as per Perth Protocol after 6  weeks for all our Robot-assisted TKA optimizes the assessment of liga- patients to ensure TKA components are in desired posi- ment balance but there are other methods published, tions (Fig. 5 and Table 3). Relative to the trans epicondy- such as mechanical tensioners and ‘kinetic sensor’ and lar axis, 74% of cases were aligned, 18% were externally second-generation electronic devices. All these devices rotated more than 3 degrees to the TEA and 8% were could reportedly provide objective quantitative assess- internally rotated more than 3 degrees to the TEA. ment of the soft tissue envelope intraoperatively, thus allowing for appropriate releases to ensure the knees are balanced and stable [9–11]. Elmallah et al. compared the experience of a surgeon with 30-years of experience to balance TKAs with sensor-guided TKAs, where releases were allowed to optimize balance with the sensor values. Sensor readings provided feedback to the performance of soft tissue releases and improve balance in TKAs well above the surgeon’s feel [12]. A meta-analysis by Batailer et al. reviewed 27 publications with maximum follow-up time of 26 months [13]. Standard surgeon assessment of knee balance was a poor predictor of the true soft tis- sue balance when compared to sensor data guidance, but prospective comparative data found no demonstrable dif- ference in clinical outcomes, the range of movement or complications at 1 year [13]. Moore et  al. reported an average of 3.03 surgical cor- rections per patient using ‘Verasence’ to achieve balance [14]. This included a total of 331 MCL Pie-crusting, 69 Arcuate releases, 35 posterior capsule releases, 13 ITB releases and 19 popliteus releases [14]. With the robot- assisted TKA, pre-planning and assessment of ligament Fig. 5 Rotation of femoral component from TEA balance before bone cuts are made can decrease the soft Selvanathan et al. Arthroplasty (2023) 5:28 Page 6 of 7 tissue releases required for balance as projected in our demonstrating and establishing a baseline for required study. soft tissue release in a mechanically aligned TKA with With early navigation, Goudie et  al. reported that flexion gap balancing in a robot-assisted TKA. 5 (2.2%) patients out of 224 TKA required releases (4 medial and 1 lateral) using computer navigated TKA [15]. Conclusion Deformity ranged from 25 degrees of varus to 27 degrees Robot-assisted TKA has been available for over 5  years of valgus. Computer-navigated TKA provided accuracy and this important study added to the body of knowl- of bone cuts and component alignment [16] but there edge by investigating the required soft tissue releases was no objective assessment of a balanced knee apart using robot-technique in a mechanically aligned flexion from the ‘surgeons feel factor’. MacDessi et  al. already gap balanced TKA. Based on bone cut precision, soft tis- concluded that surgeon defined assessment (SDA) is a sue parameters delivered by the robot algorithm allows poor measure of soft tissue assessment in TKA [8]. the surgeon to titrate the soft tissue releases needed to Robot used in TKA is an advanced navigation machine achieve balance and in our series a release of any form that provides features of computer-navigated TKA and was required in 29% of cases with more than half of these soft tissue assessment, which is the key factor to achiev- only involving the PCL. ing a balanced knee. A prospective randomized control study is required to To date, no agreement has been reached regarding the further evaluate the differences between robot and non- right amount of force required for joint distraction and, robot input in balancing the soft tissues. in most cases, it depends on a surgeon’s preference. The Acknowledgements knee forces vary from extension to flexion and soft tis - Conception and design of the work, NS and RS; The acquisition and analysis sue balance changes depending on the joint distraction NS, interpretation of data, NS and RS; Drafting and substantial revision, NS, FEA forces being applied [17]. The strength of joint distraction and RS. All authors read and approved the final manuscript.. force is essential in the assessment of soft-tissue balance Authors’ contributions [17]. Conventional ligament spreaders are being used but N.S. and R.S.: conception and design of the work; N.S.: acquisition and analysis; this method can cause oversized and asymmetrical gaps N.S. and R.S.: interpretation of data, N.S., F.E.A. and R.S.: drafting and substantial revision. All authors read and approved the final manuscript. [18]. In our series, the FuZion device (Fig.  6) was used to quantitatively measure the opening of medial and lat- Funding eral space when forces were being applied gradually and The authors declare there are no funding support for this study. to ensure a balanced flexion gap. With this information, Availability of data and materials appropriately measured bone cuts can be made. The data that support the findings of this study are available from Nepean The drawback of this study was that there were no Blue Mountain Local Health District, but restrictions apply to the availability of these data, which were used under license for the current study, and so control cohorts for proper comparison. Also, the num- are not publicly available. Data are however available from the authors upon ber of surgeries performed was few. However, the reasonable request and with permission of Nepean Blue Mountain Local strength of this study was prospectively collected data Health District. in a consecutive series, all with a reproducible technique Declarations Ethics approval and consent to participate The study received the approval of Nepean Blue Mountain Local Health District Human Research Ethics Committee (2022/ETH01109). Consent for publication Not applicable. Competing interests The authors declare that they have no competing interests. Received: 30 December 2022 Accepted: 4 April 2023 References 1. Plaskos C, Wakelin E, Shalhoub S, Lawrence J, Keggi J, Koenig JA, et al. Soft-tissue release rates in robotic-assisted gap-balancing and measured-resection total knee arthroplasty. Orthopaed Proc. 2020;102-B((SUPP_2)):1. Fig. 6 FuZion device for ligament balancing S elvanathan et al. Arthroplasty (2023) 5:28 Page 7 of 7 2. Ranawat AS, Ranawat CS, Elkus M, Rasquinha VJ, Rossi R, Babhulkar S. Total knee arthroplasty for severe valgus deformity. J Bone Joint Surg Am. 2005;87 Suppl 1(Pt 2):271–84. 3. MacDessi SJ, Griffiths-Jones W, Harris IA, Bellemans J, Chen DB. Coronal Plane Alignment of the Knee (CPAK) classification. Bone Joint J. 2021;103-B(2):329–37. 4. Clark G, Steer R, Tippett B, Wood D. Short-term benefits of robotic assisted total knee arthroplasty over computer navigated total knee arthroplasty are not sustained with no difference in postoperative patient-reported outcome measures. Arthroplasty Today. 2022;14:210-5 e0. 5. Morcos MW, Lanting BA, Webster J, Howard JL, Bryant D, Teeter MG. Eec ff t of medial soft tissue releases during posterior-stabilized total knee arthroplasty on contact kinematics and patient-reported outcomes. J Arthroplasty. 2019;34(6):1110–5. 6. Rhoads DD, Noble PC, Reuben JD, Mahoney OM, Tullos HS. The effect of femoral component position on patellar tracking after total knee arthro- plasty. Clin Orthop Relat Res. 1990;260:43–51. 7. Firer P, Gelbart B. Balancing of total knee arthroplasty by bone cuts achieves accurately balanced soft tissues without the need for soft tissue releases. J ISAKOS. 2018;3(5):263–8. 8. MacDessi SJ, Gharaibeh MA, Harris IA. How Accurately Can Soft Tissue Balance Be Determined in Total Knee Arthroplasty? J Arthroplasty. 2019;34(2):290-4.e1. 9. Gustke KA, Golladay GJ, Roche MW, Elson LC, Anderson CR. A Targeted Approach to Ligament Balancing Using Kinetic Sensors. J Arthroplasty. 2017;32(7):2127–32. 10. Nielsen ES, Hsu A, Patil S, Colwell CW Jr, D’Lima DD. Second-Generation Electronic Ligament Balancing for Knee Arthroplasty: A Cadaver Study. J Arthroplasty. 2018;33(7):2293–300. 11. Cho KJ, Seon JK, Jang WY, Park CG, Song EK. Objective quantification of ligament balancing using VERASENSE in measured resection and modified gap balance total knee arthroplasty. BMC Musculoskelet Disord. 2018;19(1):266. 12. Elmallah RK, Mistry JB, Cherian JJ, Chughtai M, Bhave A, Roche MW, et al. Can We Really “Feel” a Balanced Total Knee Arthroplasty? J Arthroplasty. 2016;31(9 Suppl):102–5. 13. Batailler C, Swan J, Marinier ES, Servien E, Lustig S. Current role of intra- operative sensing technology in total knee arthroplasty. Arch Orthop Trauma Surg. 2021;141(12):2255–65. 14. Moore RE, Conditt MA, Roche MW, Verstraete MA. How to Quantitatively Balance a Total Knee? A Surgical Algorithm to Assure Balance and Control Alignment. Sensors (Basel). 2021;21(3):700. 15. Goudie S, Deep K. Collateral soft tissue release in primary total knee replacement. Comput Aided Surg. 2014;19(1–3):29–33. 16. Jones CW, Jerabek SA. Current role of computer navigation in total knee arthroplasty. J Arthroplasty. 2018;33(7):1989–93. 17. Nagai K, Muratsu H, Matsumoto T, Miya H, Kuroda R, Kurosaka M. Soft tissue balance changes depending on joint distraction force in total knee arthroplasty. J Arthroplasty. 2014;29(3):520–4. 18. Ferreira MC, Franciozi CES, Kubota MS, Priore RD, Ingham SJM, Abdalla RJ. Is the Use of Spreaders an Accurate Method for Ligament Balancing? J Arthroplasty. 2017;32(7):2262–7. Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in pub- lished maps and institutional affiliations. Re Read ady y to to submit y submit your our re researc search h ? Choose BMC and benefit fr ? 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Incidence of soft tissue releases in robotic assisted cementless TKA with mechanical alignment and flexion gap balancing

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10.1186/s42836-023-00188-1
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Abstract

Background To ensure the success of total knee arthroplasty ( TKA), precise bone cuts and a well-balanced soft tissue envelope are crucial. Soft tissue release may be necessary, subject to various factors. Therefore, documenting the type, frequency, and necessity of soft tissue releases can establish a benchmark for comparing different alignment tech- niques and philosophies and evaluating their outcomes. The purpose of this study was to demonstrate that robotic- assisted knee surgery requires minimal soft tissue release. Methods We prospectively documented and retrospectively reviewed the soft tissue releases employed in securing ligament balance in the first 175 patients who received robotic-assisted TKAs at Nepean Hospital. ROSA was utilized in all surgeries with the aim of restoring mechanical coronal alignment, with a flexion gap balancing technique. Surgeries were performed between December 2019 to August 2021 by a single surgeon who used a standard medial parapatellar approach without a tourniquet, and the cementless persona prosthesis. All patients were followed up for a minimum of 6 months post-surgery. Soft tissue releases included any form of medial release for varus knee, postero- lateral release for valgus knee and PCL fenestration or sacrifice. Results There were 131 female and 44 male patients, aged between 48 to 89 years (average 60 years). The preopera- tive HKA ranged from 22 degrees varus to 28 degrees valgus, with 71% of patients presenting with a varus deformity. For the whole group, the no need for soft tissue release was documented in 123 patients (70.3%), small fenestrated releases of PCL in 27 (15.4%), sacrifice of PCL in 8 (4.5%), medial releases in 4 (2.3%) and posterolateral releases in 13 (7.4%). In 29.7% of patients in whom a soft tissue release was necessary for balance, over half were/received minor fenestrations of the PCL. Outcomes to date included no revisions or impending revisions, 2 MUAs (1%), and Oxford knee scores averaged 40 at 6 months. Conclusion We concluded that Robot technology enhanced the precision of bone cuts and allowed for titration of required soft tissue releases to achieve optimal balance. Keywords Robotic-assisted total knee arthroplasty, TKA, ROSA, Mechanical alignment, Soft tissue release Introduction Robot-assist TKA allows for execution and validation of *Correspondence: higher precision of bone cuts [1]. It also makes it possi- Femi E. Ayeni femi.ayeni@sydney.edu.au ble to intraoperatively assess soft tissue balance objec- Department of Orthopaedics, Nepean Hospital, Derby Street, tively, which is critical to a ‘balanced and stable knee’. It is Kingswood, Penrith, NSW 2747, Australia important to achieve a balanced knee both clinically and Nepean Institute of Academic Surgery, Nepean Clinical School, The University of Sydney, 62 Derby St, Kingswood, NSW 2747, Australia in terms of robotic parameters. © The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http:// creat iveco mmons. org/ licen ses/ by/4. 0/. Selvanathan et al. Arthroplasty (2023) 5:28 Page 2 of 7 Information obtained enables surgeons to gauge the outcome of knee balancing before and after bone resec- tion. Digital information prevents/avoids redundant bone cuts and soft tissue release. Moreover, from the ‘surgeon’s feel’ of a balanced knee, which has been demonstrated to be less than accurate, current technologies can allow for digital representation of soft tissue laxity and inform the required soft tissue releases to achieve balance. The com - bination of clinical assessment and digital parameters enables surgeons to evaluate and respond to the required actions needed to attain better balance. Managing a severe coronal plane knee deformity using conventional instrumentation may require significant soft tissue release, which may be compounded by relative inaccuracy of the tibial or femoral bone cuts, thereby car- rying a risk of over-release and instability [2]. Document- ing and analyzing the number and extent of soft tissue release with each technology and alignment philosophy may assist in working towards the most appropriate and Fig. 1 Standard surgical exposure prior to bone cuts reproducible technique to achieve balance with the least invasiveness and thereby improve patient outcomes fur- trackers were placed within the standard incision. The ther [3]. Thus, this study sought to investigate if minimal pre-cut balancing plan was made with the robot after soft to no soft tissue release is required in robotic-assisted tissue laxity was incorporated into the balance algorithm knees. and after assessment in terms of the range of motion with varus and valgus loading. Methods In all cases, the femoral and tibial bone cuts were We prospectively documented and retrospectively aligned perpendicular to the mechanical axis (0 degrees reviewed the soft tissue release required in securing liga- varus valgus). Balancing equation aimed to ensure at ment balance in the first 175 consecutive robot-assisted least 19 mm of joint space in the medial compartment for TKAs in our centre. The robotic surgical assistant ROSA a valgus deformity or the lateral compartment for a varus (Zimmer Biomet, Warsaw, IN, USA) was used in all sur- deformity. The opposite compartment was accepted geries, aiming for restoring mechanical alignment with whenever the tighter joint space was observed, as the HKA of 0 and a flexion gap balance by using the ligament surgeon was prepared to perform the required soft tis- tensioning “FuZion” device (Zimmer Biomet, Warsaw, sue releases to ensure balance after bone resection and IN, USA). Surgeries were performed between December removal of remaining osteophytes. 2019 to August 2021 by a single surgeon using a standard Once the proximal tibial and distal femoral cuts were medial parapatellar approach without a tourniquet. All made and validated, the remaining osteophytes were implants were cementless Persona TKA prosthesis (Zim- removed and the extension space assessed, with the mer Biomet, Warsaw, IN, USA) and all patients were fol- spacer block equivalent to 19 mm space. The aim was to lowed up for a minimum of 6  months post-surgery. Soft ensure sufficient space in one compartment to accommo - tissue releases took into account any form of medial side date the smallest spacer block and ensure that extension release for varus knee, posterolateral fenestrated release was between 0 and 10 degrees. If the medial compart- and/or lateral retinacular release for valgus knee and PCL ment was tight, then a posteromedial release would be fenestration or sacrifice. performed as needed to effect balance and fully accom - The standard surgical exposure suffices just to expose modate the spacer in both compartments. If the lateral the anterior aspect of the tibia to ensure juxtaposition compartment was tight, then a fenestrated posterolateral of the tibial cutting block of the robot arm. Any further capsular release plus or minus PCL sacrifice was done exposure of the anteromedial tibia subsequently was as needed to achieve balance and fully accommodate performed as a mean of posteromedial release. Figure  1 the spacer. These releases would be documented. The shows our standard surgical exposure without any soft FuZion device was then used to ensure a balanced flex - tissue release. ion space and was tensioned by using its ratchet system All large and accessible osteophytes were removed. It is in 95 degrees of flexion. The robot requires the knee to of note that in this group of patients the standard array S elvanathan et al. Arthroplasty (2023) 5:28 Page 3 of 7 be between 90 and 95 degrees of flexion at this point of Table 1 Results of soft tissue releases for varus knee tensioning to register the required rotation of the femo- Releases in Varus HKA < -20 (varus Total patients- 121 ral component to balance the flexion space. This rotation knee) of the femoral component was then incorporated into Types of soft tissue releases n Percentage the flexion balance algorithm, and final flexion balance Nil releases 86 71% was confirmed, ensuring at least 19  mm medial and lat - Fenestrated PCL 24 20% eral joint spaces in flexion. The final femoral 4 in 1 bone PCL Sacrificed 7 6% cuts were then performed, and the rotation of the femo- Medial releases 4 3% ral component was then confirmed to effect flexion gap balance independent of the transepicondylar or posterior condylar axes. The trial reduction is the final opportunity to ensure (Fig.  3). Included in this patient group requiring soft tis- balance is achieved and if further releases are required. sue releases were 4 patients that also needed a bone re- This is particularly relevant for sagittal balance and flex - cut (3 femurs, 1 tibia). In the remaining 171 patients, ion range. If required, the PCL may be fenestrated if their initial bone resections were validated by ROSA and any tibial lift off is observed. After the implantation of found to be within the 1.5  mm accuracy zone set by the true prosthesis, the final balance through the range was robot software. assessed and documented. The need for soft tissue releases was higher in patients presenting with valgus knee deformities (Table  2). In Data analysis and statistical analysis patients whose coronal deformity was greater than 2 We used descriptive statistics to report the incidence degrees varus or valgus, the soft tissue release rate was of each category of cases treated. All statistical analyses 29% in varus knees) against 53% in valgus knees. were performed by using Microsoft Excel (v.16.45). The patella was not resurfaced in 137 patients (78%) and a lateral release was required in 18 patients (10%). Results A lateral release was needed in 6 patients (4%) in those The subjects included 131 female and 44 male patients whose patella was not resurfaced. Four of the patients and were all within the age range from 48 to 89 (average receiving patella resurfacing required augmented tan- 60 years) years. The soft tissue releases were assessed as a talum patella due to severe patellofemoral arthritis. whole group and then in subgroups for varus deformity The tibial polyethylene inserts were cruciate retaining greater than 2 degrees and valgus deformity more than 2 CR in 131 patients (75%), medial congruent MC in 42 degrees. The preoperative HKA ranged from 22 degrees patients (24%), ultra-congruent UC in 1 patient and con- varus to 28 degrees valgus, with 71% of the patients pre- strained posterior stabilised CPS in 1 patient. Outcomes senting with a varus deformity (Fig. 2, Table 1). to date included no revisions or impending revisions, 2 For the whole group, no soft tissue release was required MUAs (1%), and Oxford knee scores that averaged 40 at in 123 patients (70.3%). In 52 patients (29.7%), some form 6 months. of soft tissue release was needed to ensure balance. The soft tissue releases performed included small fenestrated Discussion releases of PCL in 27 patients (15.4%), sacrifice of PCL Soft tissue releases are utilized ala carte and the current in 8 patients (4.5%), posteromedial releases in 4 patients use of the technique has the potential to optimize balance (2.3%) and posterolateral releases in 13 patients (7.4%) and outcomes. A study by Plascos et al. [1] reported that Fig. 2 Preoperative HKA deformity Selvanathan et al. Arthroplasty (2023) 5:28 Page 4 of 7 Fig. 3 Soft tissue releases performed Table 2 Result of soft tissue releases for valgus knees thereby facilitating early mobilization and discharge, with a significant reduction in the length of hospital stay. Releases in valgus HKA > 2° Total patients (n = 32) These early benefits of minimizing soft tissue releases (valgus knee) during TKA, however, did not translate to any long-term Types of soft tissue releases n Percentage benefits as there was no difference between groups at Nil releases 15 47% 2  years in terms of the Oxford knee score or forgotten Fenestrated PCL 3 9% knee score. PCL sacrifice 1 3% With the robot-assisted TKA, we could avoid unneces- Posterolateral releases 13 41% sary soft tissue release optimizing coronal alignment to the mechanical axis to achieve a balanced knee. However, as in study by Morcos et al. [5] and other reports, no dif- ference was identified in patient-reported outcomes after robotic-assisted gap-balancing required less soft tissue 1 year no matter minimal or extensive soft tissue releases release compared to robot-assisted measured resection were used in TKA. and conventional measured resection. In the study, 31% In our study, we considered small fenestrated releases out of 615 robotic-assisted gap balancing required one of PCL (Fig.  4) and PCL sacrifices for the soft tissue or more soft tissue releases. Similarly, our study reported release. The total percentage of patients in these sub - that 29.7% of the patients that had robotic TKA required groups was 19.9%. Some elected to sacrifice the PCL a soft tissue release. Clark et  al. [4] reported on the sig- routinely and substitute with a cam post PS (posterior nificant short-term benefits of robotic TKA as compared stabilizer) design or utilize an MC (medial congruent) with conventional TKA, as indicated by the decreased poly insert and, as a result, the actual rate of soft tissue need for soft tissue releases, in particular, improved releases required for correction in the coronal plane was range of motion and decreased pain scores on day 1 and only 9.7%. We believe that preserving the PCL provides a a reduction in narcotic use on day 2. Total reduction in leverage to retain, fenestrate, or remove to achieve better morphine-equivalent dosage was also significantly lower, balance of the knee in flexion and extension (Fig. 3). Fig. 4 Fenestrated PCL performed using a size 15 blade S elvanathan et al. Arthroplasty (2023) 5:28 Page 5 of 7 More patients with valgus knee deformity required Table 3 Rotation of femoral component from TEA (+ 3° = External rotation, -3° = Internal rotation) soft tissue release in comparison with patients with varus knee deformity (53% vs. 29%). Based on our sub- Degrees of rotation n Percentage analysis, we noted that a preoperative HKA greater 0 ± 3 123 74% than 12 degrees was more likely to require a soft tissue > + 3 30 18% release. For patients with a valgus deformity less than 6 < -3 14 8% degrees the release rate was 0%, for valgus between 6 to 12 degrees the release rate was 22% and for 12 degrees or more the rate of release needed to achieve balance was 67%. This value can serve as a predictor in future Firer et  al. reported that, in conventional instru- to determine the need for soft tissue releases if an MA mented TKA, no soft tissue releases were secured [7] philosophy is followed. Furthermore, we acknowledge when ligament balance was secured completely by some authors might consider the utilization of a lateral bone cuts and implant placement to accommodate the parapatellar approach in more severe valgus deformi- soft tissues. PCL was removed in all patients. Bone ties but for standardization across our cohort, we used cuts were made based on a template, depending on the the medial parapatellar approach in all patients regard- degree of deformity calculated from the pre-operative less of presenting deformity. There was no conversion X-ray by using a gap balancing technique for both flex - to higher constraint prosthesis in any of our patients ion and extension. However, no objective ligament bal- intraoperatively. ancing assessment was conducted intraoperatively due Lateral retinacular releases were performed if the to the debate on what is the appropriate value of ten- patella was not tracking centrally in the trochlear groove sion [7]. In this study, a balanced knee depended on the at final reduction and 10% of our patients required lateral ‘surgeons feel factor’ or ‘Surgeon-defined Assessment’ retinacular release, and 4% were from the non-resurfaced (SDA). MacDessi et  al., in their paper, concluded that group. The effect of TKA component positioning could SDA was a poor measure of soft tissue assessment in contribute to patella mal-tracking [6]. We routinely per- TKA [8]. form CT as per Perth Protocol after 6  weeks for all our Robot-assisted TKA optimizes the assessment of liga- patients to ensure TKA components are in desired posi- ment balance but there are other methods published, tions (Fig. 5 and Table 3). Relative to the trans epicondy- such as mechanical tensioners and ‘kinetic sensor’ and lar axis, 74% of cases were aligned, 18% were externally second-generation electronic devices. All these devices rotated more than 3 degrees to the TEA and 8% were could reportedly provide objective quantitative assess- internally rotated more than 3 degrees to the TEA. ment of the soft tissue envelope intraoperatively, thus allowing for appropriate releases to ensure the knees are balanced and stable [9–11]. Elmallah et al. compared the experience of a surgeon with 30-years of experience to balance TKAs with sensor-guided TKAs, where releases were allowed to optimize balance with the sensor values. Sensor readings provided feedback to the performance of soft tissue releases and improve balance in TKAs well above the surgeon’s feel [12]. A meta-analysis by Batailer et al. reviewed 27 publications with maximum follow-up time of 26 months [13]. Standard surgeon assessment of knee balance was a poor predictor of the true soft tis- sue balance when compared to sensor data guidance, but prospective comparative data found no demonstrable dif- ference in clinical outcomes, the range of movement or complications at 1 year [13]. Moore et  al. reported an average of 3.03 surgical cor- rections per patient using ‘Verasence’ to achieve balance [14]. This included a total of 331 MCL Pie-crusting, 69 Arcuate releases, 35 posterior capsule releases, 13 ITB releases and 19 popliteus releases [14]. With the robot- assisted TKA, pre-planning and assessment of ligament Fig. 5 Rotation of femoral component from TEA balance before bone cuts are made can decrease the soft Selvanathan et al. Arthroplasty (2023) 5:28 Page 6 of 7 tissue releases required for balance as projected in our demonstrating and establishing a baseline for required study. soft tissue release in a mechanically aligned TKA with With early navigation, Goudie et  al. reported that flexion gap balancing in a robot-assisted TKA. 5 (2.2%) patients out of 224 TKA required releases (4 medial and 1 lateral) using computer navigated TKA [15]. Conclusion Deformity ranged from 25 degrees of varus to 27 degrees Robot-assisted TKA has been available for over 5  years of valgus. Computer-navigated TKA provided accuracy and this important study added to the body of knowl- of bone cuts and component alignment [16] but there edge by investigating the required soft tissue releases was no objective assessment of a balanced knee apart using robot-technique in a mechanically aligned flexion from the ‘surgeons feel factor’. MacDessi et  al. already gap balanced TKA. Based on bone cut precision, soft tis- concluded that surgeon defined assessment (SDA) is a sue parameters delivered by the robot algorithm allows poor measure of soft tissue assessment in TKA [8]. the surgeon to titrate the soft tissue releases needed to Robot used in TKA is an advanced navigation machine achieve balance and in our series a release of any form that provides features of computer-navigated TKA and was required in 29% of cases with more than half of these soft tissue assessment, which is the key factor to achiev- only involving the PCL. ing a balanced knee. A prospective randomized control study is required to To date, no agreement has been reached regarding the further evaluate the differences between robot and non- right amount of force required for joint distraction and, robot input in balancing the soft tissues. in most cases, it depends on a surgeon’s preference. The Acknowledgements knee forces vary from extension to flexion and soft tis - Conception and design of the work, NS and RS; The acquisition and analysis sue balance changes depending on the joint distraction NS, interpretation of data, NS and RS; Drafting and substantial revision, NS, FEA forces being applied [17]. The strength of joint distraction and RS. All authors read and approved the final manuscript.. force is essential in the assessment of soft-tissue balance Authors’ contributions [17]. Conventional ligament spreaders are being used but N.S. and R.S.: conception and design of the work; N.S.: acquisition and analysis; this method can cause oversized and asymmetrical gaps N.S. and R.S.: interpretation of data, N.S., F.E.A. and R.S.: drafting and substantial revision. All authors read and approved the final manuscript. [18]. In our series, the FuZion device (Fig.  6) was used to quantitatively measure the opening of medial and lat- Funding eral space when forces were being applied gradually and The authors declare there are no funding support for this study. to ensure a balanced flexion gap. With this information, Availability of data and materials appropriately measured bone cuts can be made. The data that support the findings of this study are available from Nepean The drawback of this study was that there were no Blue Mountain Local Health District, but restrictions apply to the availability of these data, which were used under license for the current study, and so control cohorts for proper comparison. Also, the num- are not publicly available. Data are however available from the authors upon ber of surgeries performed was few. However, the reasonable request and with permission of Nepean Blue Mountain Local strength of this study was prospectively collected data Health District. in a consecutive series, all with a reproducible technique Declarations Ethics approval and consent to participate The study received the approval of Nepean Blue Mountain Local Health District Human Research Ethics Committee (2022/ETH01109). Consent for publication Not applicable. Competing interests The authors declare that they have no competing interests. Received: 30 December 2022 Accepted: 4 April 2023 References 1. Plaskos C, Wakelin E, Shalhoub S, Lawrence J, Keggi J, Koenig JA, et al. Soft-tissue release rates in robotic-assisted gap-balancing and measured-resection total knee arthroplasty. Orthopaed Proc. 2020;102-B((SUPP_2)):1. Fig. 6 FuZion device for ligament balancing S elvanathan et al. Arthroplasty (2023) 5:28 Page 7 of 7 2. Ranawat AS, Ranawat CS, Elkus M, Rasquinha VJ, Rossi R, Babhulkar S. Total knee arthroplasty for severe valgus deformity. J Bone Joint Surg Am. 2005;87 Suppl 1(Pt 2):271–84. 3. MacDessi SJ, Griffiths-Jones W, Harris IA, Bellemans J, Chen DB. Coronal Plane Alignment of the Knee (CPAK) classification. Bone Joint J. 2021;103-B(2):329–37. 4. Clark G, Steer R, Tippett B, Wood D. Short-term benefits of robotic assisted total knee arthroplasty over computer navigated total knee arthroplasty are not sustained with no difference in postoperative patient-reported outcome measures. Arthroplasty Today. 2022;14:210-5 e0. 5. Morcos MW, Lanting BA, Webster J, Howard JL, Bryant D, Teeter MG. Eec ff t of medial soft tissue releases during posterior-stabilized total knee arthroplasty on contact kinematics and patient-reported outcomes. J Arthroplasty. 2019;34(6):1110–5. 6. Rhoads DD, Noble PC, Reuben JD, Mahoney OM, Tullos HS. The effect of femoral component position on patellar tracking after total knee arthro- plasty. Clin Orthop Relat Res. 1990;260:43–51. 7. Firer P, Gelbart B. Balancing of total knee arthroplasty by bone cuts achieves accurately balanced soft tissues without the need for soft tissue releases. J ISAKOS. 2018;3(5):263–8. 8. MacDessi SJ, Gharaibeh MA, Harris IA. How Accurately Can Soft Tissue Balance Be Determined in Total Knee Arthroplasty? J Arthroplasty. 2019;34(2):290-4.e1. 9. Gustke KA, Golladay GJ, Roche MW, Elson LC, Anderson CR. A Targeted Approach to Ligament Balancing Using Kinetic Sensors. J Arthroplasty. 2017;32(7):2127–32. 10. Nielsen ES, Hsu A, Patil S, Colwell CW Jr, D’Lima DD. Second-Generation Electronic Ligament Balancing for Knee Arthroplasty: A Cadaver Study. J Arthroplasty. 2018;33(7):2293–300. 11. Cho KJ, Seon JK, Jang WY, Park CG, Song EK. Objective quantification of ligament balancing using VERASENSE in measured resection and modified gap balance total knee arthroplasty. BMC Musculoskelet Disord. 2018;19(1):266. 12. Elmallah RK, Mistry JB, Cherian JJ, Chughtai M, Bhave A, Roche MW, et al. Can We Really “Feel” a Balanced Total Knee Arthroplasty? J Arthroplasty. 2016;31(9 Suppl):102–5. 13. Batailler C, Swan J, Marinier ES, Servien E, Lustig S. Current role of intra- operative sensing technology in total knee arthroplasty. Arch Orthop Trauma Surg. 2021;141(12):2255–65. 14. Moore RE, Conditt MA, Roche MW, Verstraete MA. How to Quantitatively Balance a Total Knee? A Surgical Algorithm to Assure Balance and Control Alignment. Sensors (Basel). 2021;21(3):700. 15. Goudie S, Deep K. Collateral soft tissue release in primary total knee replacement. Comput Aided Surg. 2014;19(1–3):29–33. 16. Jones CW, Jerabek SA. Current role of computer navigation in total knee arthroplasty. J Arthroplasty. 2018;33(7):1989–93. 17. Nagai K, Muratsu H, Matsumoto T, Miya H, Kuroda R, Kurosaka M. Soft tissue balance changes depending on joint distraction force in total knee arthroplasty. J Arthroplasty. 2014;29(3):520–4. 18. Ferreira MC, Franciozi CES, Kubota MS, Priore RD, Ingham SJM, Abdalla RJ. Is the Use of Spreaders an Accurate Method for Ligament Balancing? J Arthroplasty. 2017;32(7):2262–7. Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in pub- lished maps and institutional affiliations. Re Read ady y to to submit y submit your our re researc search h ? Choose BMC and benefit fr ? 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Journal

ArthroplastySpringer Journals

Published: Jun 7, 2023

Keywords: Robotic-assisted total knee arthroplasty; TKA; ROSA; Mechanical alignment; Soft tissue release

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