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Cited by 46Total Knee Arthroplasty OutcomesKnee injuries and reconstruction techniquesLower Extremity Biomechanics and Pathologies

Arithmetic hip‐knee‐ankle angle and stressed hip‐knee‐ankle angle: equivalent methods for estimating constitutional lower limb alignment in kinematically aligned total knee arthroplasty

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Tarassoli, Payam, Wood, Jil A., Chen, Darren B., Griffiths‐Jones, Will, Bellemans, Johan, MacDessi, Samuel J.·2022·Knee Surgery, Sports Traumatology, Arthroscopy
DOI 10.1007/s00167-022-07038-8PMC PMC9418303
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Abstract

Purpose: Kinematically aligned total knee arthroplasty (KA TKA) relies on precise determination of constitutional alignment to set resection targets. The arithmetic hip‐knee‐ankle angle (aHKA) is a radiographic method to estimate constitutional alignment following onset of arthritis. Intraoperatively, constitutional alignment may also be approximated using navigation‐based angular measurements of deformity correction, termed the stressed HKA (sHKA). This study aimed to investigate the relationship between these methods of estimating constitutional alignment to better understand their utility in KA TKA. Methods: A radiological and intraoperative computer‐assisted navigation study was undertaken comparing measurements of the aHKA using radiographs and computed tomography (CT‐aHKA) to the sHKA in 88 TKAs meeting the inclusion criteria. The primary outcome was the difference in the paired means between the three methods to determine constitutional alignment (aHKA, CT‐aHKA, sHKA). Secondary outcomes included testing agreement across measurements using Bland‐Altman plots and analysis of subgroup differences based on different patterns of compartmental arthritis. Results: There were no statistically significant differences between any paired comparison or across groups (aHKA vs. sHKA: 0.1°, p = 0.817; aHKA vs. CT‐aHKA: 0.3°, p = 0.643; CT‐aHKA vs. sHKA: 0.2°, p = 0.722; ANOVA, p = 0.845). Bland‐Altman plots were consistent with good agreement for all comparisons, with approximately 95% of values within limits of agreement. There was no difference in the three paired comparisons (aHKA, CT‐aHKA, and sHKA) for knees with medial compartment arthritis. However, these findings were not replicated in knees with lateral compartment arthritis. Conclusions: There was no significant difference between the arithmetic HKA (whether obtained using CT or radiographs) and the stressed HKA in this analysis. These findings further validate the preoperative arithmetic method and support use of the intraoperative stressed HKA as techniques to restore constitutional lower limb alignment in KA TKA. Level of evidence: III.

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  • The ability of CT-based robotics to define constitutional alignment and CPAK has been established.

    “The ability of CT-based robotics to define constitutional alignment and CPAK has been established [16–18], yet it remains unknown if imageless intraoperative robotic data can accurately describe CPAK parameters [19–23].”

    From Imageless robotic total knee arthroplasty determines similar coronal plane alignment of the knee (CPAK) parameters to long leg radiographs (2024) · cites this paper as [16]

    The Methods describe using CT-based Mako robotic planning to calculate aHKA, and the Discussion reports high agreement between CT-derived and radiographic measurements of constitutional alignment (page numbers unavailable). The paper does not establish that CT-based robotics can define CPAK; CPAK appears in the cited references, but no CPAK classification is evaluated here. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

  • A 1° difference was determined clinically sufficient to power the study, and similar patient numbers have been used in other studies comparing LLR to CT for CPAK.

    “However, a 1° difference was determined clinically sufficient to power our study and similar patient numbers have been used in other studies comparing LLR to CT for CPAK [16, 18].”

    From Imageless robotic total knee arthroplasty determines similar coronal plane alignment of the knee (CPAK) parameters to long leg radiographs (2024) · cites this paper as [16]

    The Methods (Study group; Study design, pages unavailable) report 76 patients and 88 knees and compare measurements from long-leg radiographs with CT, supporting the citation as an example of a similarly sized study. The paper compares arithmetic hip-knee-ankle angles, however, rather than explicitly comparing CPAK classifications. The citing authors’ 1° threshold concerns their own study; this source used a 1.5° equivalence margin (Methods, Sample size calculation). (LLM, conf=0.84)

    Experimental — accuracy not yet measured

  • Some methods based on CT or MRI use proprietary algorithms that may not be accessible to all surgeons.

    “Some of the methods based on CT or MRI use proprietary algorithms that may not be accessible to all surgeons [14–17].”

    From Imageless robotic total knee arthroplasty determines similar coronal plane alignment of the knee (CPAK) parameters to long leg radiographs (2024) · cites this paper as [16]

    The Methods (Radiographic technique; Computed tomographic and robotic analysis for CT-aHKA; page not provided) describe a CT-based method using Mako software, with a product specialist determining anatomical landmarks. The paper does not state that the software uses proprietary algorithms, that surgeons may lack access to them, or that this applies to MRI-based methods. (LLM, conf=0.76)

    Experimental — accuracy not yet measured

  • Tarassoli et al. found no significant differences between radiograph-based aHKA, CT-based aHKA, or stressed HKA.

    “They found no significant differences between radiograph-based aHKA, CT-based aHKA, or stressed HKA.”

    From Imageless robotic total knee arthroplasty determines similar coronal plane alignment of the knee (CPAK) parameters to long leg radiographs (2024) · cites this paper as [16]

  • Tarassoli et al. reported standard deviations for CT-based HKA and stressed HKA, in comparison to radiograph-based aHKA, of 5.3° and 4.2°, respectively.

    “Standard deviations for CT-based HKA and stressed HKA, in comparison to radiograph-based aHKA, were 5.3° and 4.2°, respectively.”

    From Imageless robotic total knee arthroplasty determines similar coronal plane alignment of the knee (CPAK) parameters to long leg radiographs (2024) · cites this paper as [16]

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Research works printed but not linked: 53

  1. [1]Antonios JK Korber S Sivasundaram L Mayfield C Kang HP Oakes DA Trends in computer navigation and robotic assistance for total knee arthroplasty in the United States: an analysis of patient and hospital factors Arthroplast Today 2019 5 88 95 10.1016/j.artd.2019.01.002 31020030 PMC6470347 · DOI
  2. [2]Kayani B Konan S Ahmed S Chang J Ayuob A Haddad F The effect of anterior cruciate ligament resection on knee biomechanics Bone Jt J 2020 102-B 4 442 448 10.1302/0301-620X.102B4.BJJ-2019-1238.R2 32228066 · DOI
  3. [3]Babazadeh S Dowsey MM Bingham RJ Ek ET Stoney JD Choong PF The long leg radiograph is a reliable method of assessing alignment when compared to computer-assisted navigation and computer tomography Knee 2013 20 242 249 10.1016/j.knee.2012.07.009 22892197 · DOI
  4. [4]Bellemans J Colyn W Vandenneucker H Victor J The Chitranjan Ranawat award: is neutral mechanical alignment normal for all patients? The concept of constitutional varus Clin Orthop Relat Res 2012 470 45 53 10.1007/s11999-011-1936-5 21656315 PMC3237976 · DOI
  5. [5]Bellemans J Vandenneucker H Vanlauwe J Victor J The influence of coronal plane deformity on mediolateral ligament status: an observational study in varus knees Knee Surg Sports Traumatol Arthrosc 2010 18 152 156 10.1007/s00167-009-0903-0 19730815 · DOI
  6. [6]Blakeney W Clement J Desmeules F Hagemeister N Riviere C Vendittoli PA Kinematic alignment in total knee arthroplasty better reproduces normal gait than mechanical alignment Knee Surg Sports Traumatol Arthrosc 2018 27 5 1410 1417 10.1007/s00167-018-5174-1 30276435 · DOI · Paper page
  7. [7]Bland JM Altman DG Measuring agreement in method comparison studies Stat Methods Med Res 1999 8 135 160 10.1177/096228029900800204 10501650 · DOI · Paper page
  8. [8]Bugbee WD Mizu-Uchi H Patil S D'Lima D Accuracy of implant placement utilizing customized patient instrumentation in total knee arthroplasty Adv Orthop 2013 2013 891210 10.1155/2013/891210 24151556 PMC3787656 · DOI
  9. [9]Burn E Prieto-Alhambra D Hamilton TW Kennedy JA Murray DW Pinedo-Villanueva R Threshold for computer- and robot-assisted knee and hip replacements in the English National Health Service Value Health 2020 23 719 726 10.1016/j.jval.2019.11.011 32540229 · DOI
  10. [10]Cerejo R Dunlop DD Cahue S Channin D Song J Sharma L The influence of alignment on risk of knee osteoarthritis progression according to baseline stage of disease Arthritis Rheum 2002 46 2632 2636 10.1002/art.10530 12384921 · DOI
  11. [11]Chauhan SK Clark GW Lloyd S Scott RG Breidahl W Sikorski JM Computer-assisted total knee replacement. A controlled cadaver study using a multi-parameter quantitative CT assessment of alignment (the Perth CT Protocol) J Bone Jt Surg Br 2004 86 818 823 10.1302/0301-620X.86B6.15456 15330021 · DOI
  12. [12]Clark GW Esposito CI Wood D Individualized functional knee alignment in total knee arthroplasty: a robotic-assisted technique Tech Orthop 2021 10.1097/BTO.0000000000000567 · DOI
  13. [13]Daines BK Dennis DA Gap balancing vs. measured resection technique in total knee arthroplasty Clin Orthop Surg 2014 6 1 8 10.4055/cios.2014.6.1.1 24605183 PMC3942594 · DOI
  14. [14]Dennis DA Komistek RD Kim RH Sharma A Gap balancing versus measured resection technique for total knee arthroplasty Clin Orthop Relat Res 2010 468 102 107 10.1007/s11999-009-1112-3 19789934 PMC2795818 · DOI
  15. [15]Elfring R De La Fuente M Radermacher K Assessment of optical localizer accuracy for computer aided surgery systems Comput Aided Surg 2010 15 1–3 1 12 10.3109/10929081003647239 20233129 · DOI
  16. [16]Gbejuade HO White P Hassaballa M Porteous AJ Robinson JR Murray JR Do long leg supine CT scanograms correlate with weight-bearing full-length radiographs to measure lower limb coronal alignment? Knee 2014 21 549 552 10.1016/j.knee.2013.05.009 23849161 · DOI
  17. [17]Greenberg A Kandel L Liebergall M Mattan Y Rivkin G Total knee arthroplasty for valgus deformity via a lateral approach: clinical results, comparison to medial approach, and review of recent literature J Arthroplast 2020 35 2076 2083 10.1016/j.arth.2020.03.037 32307289 · DOI
  18. [18]Griffiths-Jones W Chen DB Harris IA Bellemans J MacDessi SJ Arithmetic hip–knee–ankle angle (aHKA): an algorithm for estimating constitutional lower limb alignment in the arthritic patient population Bone Jt Open 2021 2 351 358 10.1302/2633-1462.25.BJO-2021-0028.R1 34042492 PMC8168548 · DOI · Paper page
  19. [19]Hakki S Coleman S Saleh K Bilotta VJ Hakki A Navigational predictors in determining the necessity for collateral ligament release in total knee replacement J Bone Jt Surg Br 2009 91 1178 1182 10.1302/0301-620X.91B9.22043 19721043 · DOI
  20. [20]Hino K Kutsuna T Watamori K Kiyomatsu H Ishimaru Y Takeba J Varus-valgus stability at 90 degrees flexion correlates with the stability at midflexion range more widely than that at 0 degrees extension in posterior-stabilized total knee arthroplasty Arch Orthop Trauma Surg 2017 137 1429 1434 10.1007/s00402-017-2779-7 28849298 PMC5602057 · DOI
  21. [21]Hirschmann MT Hess S Behrend H Amsler F Leclercq V Moser LB Phenotyping of hip–knee–ankle angle in young non-osteoarthritic knees provides better understanding of native alignment variability Knee Surg Sports Traumatol Arthrosc 2019 27 1378 1384 10.1007/s00167-019-05507-1 30968238 · DOI
  22. [22]Hirschmann MT Moser LB Amsler F Behrend H Leclerq V Hess S Functional knee phenotypes: a novel classification for phenotyping the coronal lower limb alignment based on the native alignment in young non-osteoarthritic patients Knee Surg Sports Traumatol Arthrosc 2019 27 1394 1402 10.1007/s00167-019-05509-z 30976825 · DOI
  23. [23]Holme TJ Henckel J Hartshorn K Cobb JP Hart AJ Computed tomography scanogram compared to long leg radiograph for determining axial knee alignment Acta Orthop 2015 86 440 443 10.3109/17453674.2014.1003488 25582134 PMC4513598 · DOI
  24. [24]Hutt JR LeBlanc MA Masse V Lavigne M Vendittoli PA Kinematic TKA using navigation: surgical technique and initial results Orthop Traumatol Surg Res 2016 102 99 104 10.1016/j.otsr.2015.11.010 26776100 · DOI
  25. [25]Kellgren JH Lawrence JS Radiological assessment of osteo-arthrosis Ann Rheum Dis 1957 16 494 502 10.1136/ard.16.4.494 13498604 PMC1006995 · DOI
  26. [26]Klasan A Putnis SE Grasso S Neri T Coolican MR Conventional instruments are more accurate for measuring the depth of the tibial cut than computer-assisted surgery in total knee arthroplasty: a prospective study Arch Orthop Trauma Surg 2020 140 801 806 10.1007/s00402-020-03403-9 32146591 · DOI
  27. [27]Lee OS Elazab A Lee YS Preoperative varus-valgus stress angle difference is valuable for predicting the extent of medial release in varus deformity during total knee arthroplasty Knee Surg Relat Res 2019 31 12 18 10.5792/ksrr.18.033 30871287 PMC6425900 · DOI
  28. [28]Lee YS Howell SM Won YY Lee OS Lee SH Vahedi H Kinematic alignment is a possible alternative to mechanical alignment in total knee arthroplasty Knee Surg Sports Traumatol Arthrosc 2017 25 3467 3479 10.1007/s00167-017-4558-y 28439636 · DOI
  29. [29]Lozano R Campanelli V Howell S Hull M Kinematic alignment more closely restores the groove location and the sulcus angle of the native trochlea than mechanical alignment: implications for prosthetic design Knee Surg Sports Traumatol Arthrosc 2018 10.1007/s00167-018-5220-z 30357423 · DOI
  30. [30]Lustig S Sappey-Marinier E Fary C Servien E Parratte S Batailler C Personalized alignment in total knee arthroplasty: current concepts SICOT J 2021 7 19 10.1051/sicotj/2021021 33812467 PMC8019550 · DOI
  31. [31]MacDessi SJ Restricted kinematic alignment in total knee arthroplasty: scientific exploration involving detailed planning, precise execution, and knowledge of when to abort Arthroplast Today 2021 10 24 26 10.1016/j.artd.2021.05.024 34277907 PMC8267482 · DOI
  32. [32]MacDessi SJ Griffiths-Jones W Chen DB Griffiths-Jones S Wood JA Diwan AD Restoring the constitutional alignment with a restrictive kinematic protocol improves quantitative soft-tissue balance in total knee arthroplasty: a randomized controlled trial Bone Jt J 2020 102-B 117 124 10.1302/0301-620X.102B1.BJJ-2019-0674.R2 PMC6974544 31888372 · DOI
  33. [33]MacDessi SJ Griffiths-Jones W Harris IA Bellemans J Chen DB The arithmetic HKA (aHKA) predicts the constitutional alignment of the arthritic knee compared to the normal contralateral knee Bone Jt Open 2020 1 339 345 10.1302/2633-1462.17.BJO-2020-0037.R1 33215122 PMC7659698 · DOI · Paper page
  34. [34]MacDessi SJ Griffiths-Jones W Harris IA Bellemans J Chen DB Coronal Plane Alignment of the Knee (CPAK) classification Bone Jt J 2021 103-B 329 337 10.1302/0301-620X.103B2.BJJ-2020-1050.R1 PMC7954147 33517740 · DOI · Paper page
  35. [35]Maderbacher G Baier C Springorum HR Zeman F Grifka J Keshmiri A Lower limb anatomy and alignment affect natural tibiofemoral knee kinematics: a cadaveric investigation J Arthroplast 2016 31 2038 2042 10.1016/j.arth.2016.02.049 27017201 · DOI
  36. [36]Mara CA Cribbie RA Paired-samples tests of equivalence Commun Stat Simul Comput 2012 41 1928 1943 10.1080/03610918.2011.626545 · DOI
  37. [37]McAuliffe MJ Vakili A Garg G Roe J Whitehouse SL Crawford R Are varus knees contracted? Reconciling the literature J Orthop Surg (Hong Kong) 2017 25 2309499017731445 10.1177/2309499017731445 28954573 · DOI
  38. [38]McEwen P Balendra G Doma K Medial and lateral gap laxity differential in computer-assisted kinematic total knee arthroplasty Bone Jt J 2019 101-B 331 339 10.1302/0301-620X.101B3.BJJ-2018-0544.R1 30813796 · DOI
  39. [39]McEwen P Dlaska C Jovanovic I Doma K Brandon B Computer-assisted kinematic and mechanical axis total knee arthroplasty: a prospective randomized controlled trial of bilateral simultaneous surgery J Arthroplast 2019 35 2 443 450 10.1016/j.arth.2019.08.064 31591010 · DOI
  40. [40]Myles PS Cui J Using the Bland–Altman method to measure agreement with repeated measures Br J Anaesth 2007 99 309 311 10.1093/bja/aem214 17702826 · DOI · Paper page
  41. [41]Niki Y Nagura T Nagai K Kobayashi S Harato K Kinematically aligned total knee arthroplasty reduces knee adduction moment more than mechanically aligned total knee arthroplasty Knee Surg Sports Traumatol Arthrosc 2018 26 1629 1635 10.1007/s00167-017-4788-z 29204861 · DOI · Paper page
  42. [42]Okamoto S Okazaki K Mitsuyasu H Matsuda S Iwamoto Y Lateral soft tissue laxity increases but medial laxity does not contract with varus deformity in total knee arthroplasty Clin Orthop Relat Res 2013 471 1334 1342 10.1007/s11999-012-2745-1 23247818 PMC3585995 · DOI
  43. [43]Orsi AD, Wakelin EA, Plaskos C, Petterwood J, Coffey S (2022) Restricted kinematic alignment achieves similar relative lateral laxity and greater joint line obliquity compared to gap balancing TKA. Knee Surg Sports Traumatol Arthrosc (Online ahead of print) 35067777
  44. [44]Paley D Pfeil J Principles of deformity correction around the knee Orthopade 2000 29 1 18 38 10663243
  45. [45]Roth JD Howell SM Hull ML Native knee laxities at 0°, 45°, and 90° of flexion and their relationship to the goal of the gap-balancing alignment method of total knee arthroplasty J Bone Joint Surg Am 2015 97 1678 1684 10.2106/JBJS.N.01256 26491132 · DOI
  46. [46]Sappey-Marinier E, Meynard P, Shatrov J, Schmidt A, Cheze L, Batailler C et al. (2022) Kinematic alignment matches functional alignment for the extension gap: a consecutive analysis of 749 primary varus osteoarthritic knees with stress radiographs. Knee Surg Sports Traumatol Arthrosc (online ahead of print) 35013747
  47. [47]Schlatterer B Linares JM Chabrand P Sprauel JM Argenson JN Influence of the optical system and anatomic points on computer-assisted total knee arthroplasty Orthop Traumatol Surg Res 2014 100 395 402 10.1016/j.otsr.2013.12.029 24835533 · DOI
  48. [48]Sharma L Song J Dunlop D Felson D Lewis CE Segal N Varus and valgus alignment and incident and progressive knee osteoarthritis Ann Rheum Dis 2010 69 1940 10.1136/ard.2010.129742 20511608 PMC2994600 · DOI
  49. [49]Sherman WF Wu VJ Robotic surgery in total joint arthroplasty: a survey of the AAHKS membership to understand the utilization, motivations, and perceptions of total joint surgeons J Arthroplast 2020 35 3474–3481 e3472 32731999
  50. [50]Solayar GN Chinappa J Harris IA Chen DB Macdessi SJ A comparison of plain radiography with computer tomography in determining coronal and sagittal alignments following total knee arthroplasty Malays Orthop J 2017 11 45 52 29021879 PMC5630051
  51. [52]Vaishya R Vijay V Birla VP Agarwal AK Inter-observer variability and its correlation to experience in measurement of lower limb mechanical axis on long leg radiographs J Clin Orthop Trauma 2016 7 260 264 10.1016/j.jcot.2016.05.010 27857500 PMC5106474 · DOI
  52. [53]Watanabe T Muneta T Sekiya I Banks SA Intraoperative joint gaps and mediolateral balance affect postoperative knee kinematics in posterior-stabilized total knee arthroplasty Knee 2015 22 527 534 10.1016/j.knee.2015.03.006 26014342 · DOI
  53. [54]Winnock de Grave P Luyckx T Claeys K Tampere T Kellens J Muller J Higher satisfaction after total knee arthroplasty using restricted inverse kinematic alignment compared to adjusted mechanical alignment Knee Surg Sports Traumatol Arthrosc 2020 30 2 488 499 10.1007/s00167-020-06165-4 32737528 PMC8866329 · DOI · Paper page

Cited by

Sorted by citations

Authors
Tarassoli, P., Wood, J. A., Chen, D. B., Griffiths‐Jones, W., Bellemans, J., & MacDessi, S. J.
Affiliations
  • <!--<label>2</label>--> Sydney Knee Specialists Suite 201, Level 2, 131 Princes Hwy 2217 Kogarah NSW Australia
  • <!--<label>1</label>--> CPAK Research Group Sydney Australia
  • Ziekenhuis Oost-Limburg (BE)
  • UNSW Sydney (AU)
Corresponding author
MacDessi, Samuel J.
ORCID
Venue
Knee Surgery, Sports Traumatology, Arthroscopy
Publisher
Wiley
Published
2022-07-11
Volume
30
Issue
9
Pages
2980-2990
ISSN
  • 0942-2056 (ISSN-L)
  • 1433-7347
DOI
10.1007/s00167-022-07038-8
PMC
PMC9418303
OpenAlex
W4285044335
Cited by
46
References
0
Citations by year
2026: 10 · 2025: 12 · 2024: 13 · 2023: 11
FWCI
8.60
Type
journal article
Language
en
Open access
Licence
Locations
  • Knee Surgery Sports Traumatology Arthroscopy (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Royal Devon and Exeter Research Repository (Royal Devon and Exeter) (submittedVersion, public-domain)
Funders
  • University of New South Wales
  • University of New South Wales Canberra
Topics
  • Health Sciences › Medicine › Surgery › Total Knee Arthroplasty Outcomes
  • Health Sciences › Medicine › Surgery › Knee injuries and reconstruction techniques
  • Physical Sciences › Engineering › Biomedical Engineering › Lower Extremity Biomechanics and Pathologies
Keywords
total knee arthroplasty, hip-knee-ankle angle, computer-assisted navigation, surgical resection planning
MeSH terms
Ankle, Biomechanical Phenomena, Humans, Knee Joint, Retrospective Studies, Arthroplasty, Replacement, Knee, Osteoarthritis, Knee, Lower Extremity

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