Varus or valgus positioning of the tibial component of a unicompartmental fixed-bearing knee arthroplasty does not increase wear

Abstract

Purpose

Higher revision rates were shown in varus- or valgus-positioned tibias in unicompartmental knee arthroplasty (UKA), but more than 15% of UKA prostheses are implanted with more than 5° of varus or valgus. This study aimed to analyze the wear rate in UKA when implanting the tibial component in either varus or valgus position versus a neutral placement at 90° to the tibial anatomical axis. The study hypothesized that a 5° varus or valgus positioning of the tibial plateau will generate less wear compared to a neutral alignment.

Methods

Wear was experimentally analyzed on a medial anatomical fixed-bearing unicompartmental knee prosthesis (Univation, Aesculap, Germany) in vitro with a customized, four-station, servohydraulic knee wear simulator, reproducing the walking cycle. The forces, loading and range of motion were applied as specified in the ISO 14243–1:2002, 5 million cycles were analyzed. The tibial components of the medial prostheses were inserted in a neutral position, with 5° varus, and 5° valgus (n = 3, each group).

Results

The wear rate decreased significantly with a 5° varus positioning (6.30 ± 1.38 mg/million cycles) and a 5° valgus positioning (4.96 ± 2.47 mg/million cycles) compared to the neutral position (12.16 ± 1.26 mg/million cycles) (p < 0.01 for the varus and the valgus position). The wear area on the inlay was slightly reduced in the varus and valgus group.

Conclusion

A varus or valgus “malpositioning” up to 5° will not lead to an increased wear. Wear was even less because of the reduced articulating contact area between the inlay and the femur. A slight varus positioning of the tibial component (parallel to the anatomical joint line) positioning can be advocated from a point of wear.

Level of evidence

Experimental study.

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References

  1. 1.

    Arnout N, Vanlommel L, Vanlommel J, Luyckx JP, Labey L, Innocenti B et al (2015) Post-cam mechanics and tibiofemoral kinematics: a dynamic in vitro analysis of eight posterior-stabilized total knee designs. Knee Surg Sports Traumatol Arthrosc 23:3343–3353

    CAS  Article  Google Scholar 

  2. 2.

    Barbadoro P, Ensini A, Leardini A, d'Amato M, Feliciangeli A, Timoncini A et al (2014) Tibial component alignment and risk of loosening in unicompartmental knee arthroplasty: a radiographic and radiostereometric study. Knee Surg Sports Traumatol Arthrosc 22:3157–3162

    CAS  Article  Google Scholar 

  3. 3.

    Batailler C, White N, Ranaldi FM, Neyret P, Servien E, Lustig S (2018) Improved implant position and lower revision rate with robotic-assisted unicompartmental knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. https://doi.org/10.1007/s00167-018-5081-5

    Article  PubMed  Google Scholar 

  4. 4.

    Cartier P, Sanouiller JL, Grelsamer RP (1996) Unicompartmental knee arthroplasty surgery. 10-year minimum follow-up period. J Arthroplasty 11:782–788

    CAS  Article  Google Scholar 

  5. 5.

    Chatellard R, Sauleau V, Colmar M, Robert H, Raynaud G, Brilhault J et al (2013) Medial unicompartmental knee arthroplasty: does tibial component position influence clinical outcomes and arthroplasty survival? J Orthopaedics 99:S219–S225

    CAS  Google Scholar 

  6. 6.

    Diezi C, Wirth S, Meyer DC, Koch PP (2010) Effect of femoral to tibial varus mismatch on the contact area of unicondylar knee prostheses. Knee 17:350–355

    Article  Google Scholar 

  7. 7.

    Grimberg A, Jansson V, Liebs T, Melsheimer O, Steinbrück A (2018) Endoprothesen register Deutschland. Springer, Berlin

    Google Scholar 

  8. 8.

    Grochowsky JC, Alaways LW, Siskey R, Most E, Kurtz SM (2006) Digital photogrammetry for quantitative wear analysis of retrieved TKA components. J Biomed Mater Res B Appl Biomater 79:263–267

    CAS  Article  Google Scholar 

  9. 9.

    Grupp TM, Utzschneider S, Schroder C, Schwiesau J, Fritz B, Maas A et al (2010) Biotribology of alternative bearing materials for unicompartmental knee arthroplasty. Acta Biomater 6:3601–3610

    CAS  Article  Google Scholar 

  10. 10.

    Gulati A, Pandit H, Jenkins C, Chau R, Dodd CA, Murray DW (2009) The effect of leg alignment on the outcome of unicompartmental knee replacement. J Bone Jt Surg Br 91:469–474

    CAS  Article  Google Scholar 

  11. 11.

    Innocenti B, Pianigiani S, Ramundo G, Thienpont E (2016) Biomechanical effects of different varus and valgus alignments in medial unicompartmental knee arthroplasty. J Arthroplasty 31:2685–2691

    Article  Google Scholar 

  12. 12.

    Kang KT, Son J, Kwon SK, Kwon OR, Koh YG (2018) Preservation of femoral and tibial coronal alignment to improve biomechanical effects of medial unicompartment knee arthroplasty: computational study. Biomed Mater Eng 29:651–664

    CAS  PubMed  Google Scholar 

  13. 13.

    Kwon OR, Kang KT, Son J, Suh DS, Baek C, Koh YG (2017) Importance of joint line preservation in unicompartmental knee arthroplasty: finite element analysis. J Orthop Res 35:347–352

    CAS  Article  Google Scholar 

  14. 14.

    Laurent JT, Yao J, Blanchard C, Crowninshield R (2003) In vitro lateral versus medial wear of a knee prosthesis. Wear 255:1101–1106

    CAS  Article  Google Scholar 

  15. 15.

    Mazzucco D, Spector M (2003) Effects of contact area and stress on the volumetric wear of ultrahigh molecular weight polyethylene. J Wear 254:514–522

    CAS  Article  Google Scholar 

  16. 16.

    Puente Reyna AL, Fritz B, Schwiesau J, Schilling C, Summer B, Thomas P et al (2018) Metal ion release barrier function and biotribological evaluation of a zirconium nitride multilayer coated knee implant under highly demanding activities wear simulation. J Biomech 79:88–96

    Article  Google Scholar 

  17. 17.

    Saikko V (2017) Effect of contact area on the wear of ultrahigh molecular weight polyethylene in noncyclic pin-on-disk tests. J Tribol Int 114:84–87

    CAS  Article  Google Scholar 

  18. 18.

    Schwiesau J, Schilling C, Utzschneider S, Jansson V, Fritz B, Blomer W et al (2013) Knee wear simulation under conditions of highly demanding daily activities–influence on an unicompartmental fixed bearing knee design. Med Eng Phys 35:1204–1211

    Article  Google Scholar 

  19. 19.

    The-Swedish-Knee-Arthroplasty-Register (2010) Annual Report 2010. Lund 10/7/2010

  20. 20.

    Weber P, Crispin A, Schmidutz F, Utzschneider S, Pietschmann MF, Jansson V et al (2013) Improved accuracy in computer-assisted unicondylar knee arthroplasty: a meta-analysis. Knee Surg Sports Traumatol Arthrosc 21:2453–2461

    Article  Google Scholar 

  21. 21.

    Weber P, Schroder C, Schmidutz F, Kraxenberger M, Utzschneider S, Jansson V et al (2013) Increase of tibial slope reduces backside wear in medial mobile bearing unicompartmental knee arthroplasty. Clin Biomech (Bristol Avon) 28:904–909

    Article  Google Scholar 

  22. 22.

    Weber P, Schroder C, Schwiesau J, Utzschneider S, Steinbruck A, Pietschmann MF et al (2015) Increase in the tibial slope reduces wear after medial unicompartmental fixed-bearing arthroplasty of the knee. Biomed Res Int. https://doi.org/10.1155/2015/736826

    Article  PubMed  PubMed Central  Google Scholar 

  23. 23.

    Weber P, Woiczinski M, Steinbruck A, Schmidutz F, Niethammer T, Schroder C et al (2018) Increase in the tibial slope in unicondylar knee replacement: analysis of the effect on the kinematics and ligaments in a weight-bearing finite element model. Biomed Res Int. https://doi.org/10.1155/2018/8743604

    Article  PubMed  PubMed Central  Google Scholar 

  24. 24.

    Wimmer MA, Nechtow W, Schwenke T, Moisio KC (2015) Knee flexion and daily activities in patients following total knee replacement: a comparison with ISO standard 14243. Biomed Res Int 2015:157541

    Article  Google Scholar 

  25. 25.

    Zietz C, Reinders J, Schwiesau J, Paulus A, Kretzer JP, Grupp T et al (2015) Experimental testing of total knee replacements with UHMW-PE inserts: impact of severe wear test conditions. J Mater Sci Mater Med 26:134

    Article  Google Scholar 

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Funding

This study was funded in part by BBraun Aesculap, Tuttlingen, Germany by providing the prosthesis System. Beside this no further external funding was used.

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Correspondence to Patrick Weber.

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Conflict of interest

VJ and PEM are advising surgeons of Aesculap, Tuttlingen, Germany. VJ, PEM and PW are advising surgeons for Medacta, Castel San Pietro, Switzerland. MW, CS and PW received research funds from Aesculap R&D projects. This did not, however, influence the study design or the collection, analysis, and interpretation of the data. It also did not influence the decision to submit the manuscript for publication.

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This article does not contain any studies with human participants or animals performed by any of the authors.

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Woiczinski, M., Schröder, C., Paulus, A. et al. Varus or valgus positioning of the tibial component of a unicompartmental fixed-bearing knee arthroplasty does not increase wear. Knee Surg Sports Traumatol Arthrosc 28, 3016–3021 (2020). https://doi.org/10.1007/s00167-019-05761-3

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Keywords

  • Wear
  • Varus valgus alignment
  • UKA