Knee Surgery, Sports Traumatology, Arthroscopy

, Volume 22, Issue 12, pp 3142–3149 | Cite as

The coronal alignment after medial unicompartmental knee arthroplasty can be predicted: usefulness of full-length valgus stress radiography for evaluating correctability

  • Yasutaka TashiroEmail author
  • Shuichi Matsuda
  • Ken Okazaki
  • Hideki Mizu-uchi
  • Umito Kuwashima
  • Yukihide Iwamoto



We aimed to clarify whether the coronal alignment after medial unicompartmental knee arthroplasty (UKA) is predictable using preoperative full-length valgus stress radiography.


Thirty-seven consecutive patients with a mean age of 71.5 ± 7.0 years awaiting medial UKA were recruited. Full-length weight-bearing radiographs of the lower limbs were obtained pre- and postoperatively. Preoperative full-length valgus stress radiography in the supine position was also performed, and the transition of the hip-knee-ankle angle (HKAA) and the weight-bearing ratio were assessed. The tibia first cut technique was used, and the distal femur was cut parallel to the cutting surface of the proximal tibia during surgery.


The mean postoperative HKAA was 2.0° ± 2.1° varus, and the mean weight-bearing ratio was 43.1 ± 7.7 %; each of these parameters demonstrated significantly strong correlations with the values on the preoperative valgus stress radiographs (p < 0.01), while the correlation between the postoperative alignment and the preoperative standing alignment without stress was moderate (p < 0.01). The postoperative alignment was slightly undercorrected compared to that observed on the valgus stress radiographs (p < 0.05), and no knees exhibited evident overcorrection compared to that on the valgus stress radiographs.


Preoperative valgus stress radiography is useful for evaluating the correctability of varus deformities and predicting the postoperative coronal alignment. For clinical relevance, performing preoperative valgus stress radiography would help to more precisely select patients and, when combined with the tibia first cut technique, aid in achieving the expected knee alignment and avoid severe undercorrection or overcorrection.

Level of evidence

Diagnostic study, Level II.


Unicompartmental knee arthroplasty Valgus stress radiography Tibia first cut technique Correctability Coronal alignment 



This study was supported by JSPS Kakenhi Grant No. 26861197.


  1. 1.
    Aleto TJ, Berend ME, Ritter MA, Faris PM, Meneghini RM (2008) Early failure of unicompartmental knee arthroplasty leading to revision. J Arthroplasty 23:159–163PubMedCrossRefGoogle Scholar
  2. 2.
    Argenson JN, Parratte S (2006) The unicompartmental knee: design and technical considerations in minimizing wear. Clin Orthop Relat Res 452:137–142PubMedCrossRefGoogle Scholar
  3. 3.
    Ariumi A, Sato T, Kobayashi K, Koga Y, Omori G, Minato I, Endo N (2010) Three-dimensional lower extremity alignment in the weight-bearing standing position in healthy elderly subjects. J Orthop Sci 15:64–70PubMedCrossRefGoogle Scholar
  4. 4.
    Bartley RE, Stulberg SD, Robb WJ 3rd, Sweeney HJ (1994) Polyethylene wear in unicompartmental knee arthroplasty. Clin Orthop Relat Res 299:18–24PubMedGoogle Scholar
  5. 5.
    Berger RA, Meneghini RM, Jacobs JJ, Sheinkop MB, Della Valle CJ, Rosenberg AG, Galante JO (2005) Results of unicompartmental knee arthroplasty at a minimum of ten years of follow-up. J Bone Joint Surg Am 87:999–1006PubMedCrossRefGoogle Scholar
  6. 6.
    Berger RA, Nedeff DD, Barden RM, Sheinkop MM, Jacobs JJ, Rosenberg AG, Galante JO (1999) Unicompartmental knee arthroplasty. Clinical experience at 6- to 10-year followup. Clin Orthop Relat Res 367:50–60PubMedCrossRefGoogle Scholar
  7. 7.
    Bruni D, Iacono F, Raspugli G, Zaffagnini S, Marcacci M (2012) Is unicompartmental arthroplasty an acceptable option for spontaneous osteonecrosis of the knee? Clin Orthop Relat Res 470:1442–1451PubMedCentralPubMedCrossRefGoogle Scholar
  8. 8.
    Bruni D, Iacono F, Russo A, Zaffagnini S, Marcheggiani Muccioli GM, Bignozzi S, Bragonzoni L, Marcacci M (2010) Minimally invasive unicompartmental knee replacement: retrospective clinical and radiographic evaluation of 83 patients. Knee Surg Sports Traumatol Arthrosc 18:710–717PubMedCrossRefGoogle Scholar
  9. 9.
    Cartier P, Sanouiller JL, Grelsamer RP (1996) Unicompartmental knee arthroplasty surgery: 10-year minimum follow-up period. J Arthroplasty 11:782–788PubMedCrossRefGoogle Scholar
  10. 10.
    Deschamps G, Chol C (2011) Fixed-bearing unicompartmental knee arthroplasty: patients’ selection and operative technique. Orthop Traumatol Surg Res 97:648–661PubMedCrossRefGoogle Scholar
  11. 11.
    Dudley TE, Gioe TJ, Sinner P, Mehle S (2008) Registry outcomes of unicompartmental knee arthroplasty revisions. Clin Orthop Relat Res 466:1666–1670PubMedCentralPubMedCrossRefGoogle Scholar
  12. 12.
    Emerson RH Jr (2007) Preoperative and postoperative limb alignment after Oxford unicompartmental knee arthroplasty. Orthopedics 30(5 Suppl):32–34PubMedGoogle Scholar
  13. 13.
    Gibson PH, Goodfellow JW (1986) Stress radiography in degenerative arthritis of the knee. J Bone Joint Surg Br 68:608–609PubMedGoogle Scholar
  14. 14.
    Hernigou P, Deschamps G (2004) Alignment influences wear in the knee after medial unicompartmental arthroplasty. Clin Orthop Relat Res 423:161–165PubMedCrossRefGoogle Scholar
  15. 15.
    Insall JN, Dorr LD, Scott RD, Scott WN (1989) Rationale of the Knee Society clinical rating system. Clin Orthop Relat Res 248:13–14PubMedGoogle Scholar
  16. 16.
    Jamali AA, Scott RD, Rubash HE, Freiberg AA (2009) Unicompartmental knee arthroplasty: past, present, and future. Am J Orthop (Belle Mead NJ) 38:17–23Google Scholar
  17. 17.
    Kawahara S, Matsuda S, Okazaki K, Tashiro Y, Iwamoto Y (2012) Is the medial wall of the intercondylar notch useful for tibial rotational reference in unicompartmental knee arthroplasty? Clin Orthop Relat Res 470:1177–1184PubMedCentralPubMedCrossRefGoogle Scholar
  18. 18.
    Keene G, Simpson D, Kalairajah Y (2006) Limb alignment in computer-assisted minimally-invasive unicompartmental knee replacement. J Bone Joint Surg Br 88:44–48PubMedCrossRefGoogle Scholar
  19. 19.
    Kennedy WR, White RP (1987) Unicompartmental arthroplasty of the knee. Postoperative alignment and its influence on overall results. Clin Orthop Relat Res 221:278–285PubMedGoogle Scholar
  20. 20.
    Kerens B, Boonen B, Schotanus MG, Lacroix H, Emans PJ, Kort NP (2013) Revision from unicompartmental to total knee replacement: the clinical outcome depends on reason for revision. Bone Joint J 95-B:1204–1208PubMedCrossRefGoogle Scholar
  21. 21.
    Kozinn SC, Scott RD (1989) Current concept review: unicondylar knee arthroplasty. J Bone Joint Surg Am 71:145–150PubMedGoogle Scholar
  22. 22.
    Levine AM, Drennan JC (1982) Physiological bowing and tibia vara. The metaphyseal-diaphyseal angle in the measurement of bowleg deformities. J Bone Joint Surg Am 64:1158–1163PubMedGoogle Scholar
  23. 23.
    Marx RG, Grimm P, Lillemoe KA, Robertson CM, Ayeni OR, Lyman S, Bogner EA, Pavlov H (2011) Reliability of lower extremity alignment measurement using radiographs and PACS. Knee Surg Sports Traumatol Arthrosc 19:1693–1698PubMedCrossRefGoogle Scholar
  24. 24.
    Matsuda S (2013) CORR insights®: the value of valgus stress radiographs in the workup for medial unicompartmental arthritis. Clin Ortop Relat Res. doi: 10.1007/s11999-013-3262-6 Google Scholar
  25. 25.
    Matsuda S, Mizu-uchi H, Miura H, Nagamine R, Urabe K, Iwamoto Y (2003) Tibial shaft axis does not always serve as a correct coronal landmark in total knee arthroplasty for varus knees. J Arthroplasty 18:56–62PubMedCrossRefGoogle Scholar
  26. 26.
    Moreland JR, Bassett LW, Hanker GJ (1987) Radiographic analysis of the axial alignment of the lower extremity. J Bone Joint Surg Am 69:745–749PubMedGoogle Scholar
  27. 27.
    Murray DW, Goodfellow JW, O’Connor JJ (1998) The Oxford medial unicompartmental arthroplasty: a ten-year survival study. J Bone Joint Surg Br 80:983–989PubMedCrossRefGoogle Scholar
  28. 28.
    Sawatari T, Tsumura H, Iesaka K, Furushiro Y, Torisu T (2005) Three-dimensional finite element analysis of unicompartmental knee arthroplasty–the influence of tibial component inclination. J Orthop Res 23:549–554PubMedCrossRefGoogle Scholar
  29. 29.
    Scott CE, Eaton MJ, Nutton RW, Wade FA, Pankaj P, Evans SL (2013) Proximal tibial strain in medial unicompartmental knee replacements: a biomechanical study of implant design. Bone Joint J 95-B:1339–1347PubMedCrossRefGoogle Scholar
  30. 30.
    Shetty GM, Mullaji A, Bhayde S, Nha KW, Oh HK (2014) Factors contributing to inherent varus alignment of lower limb in normal Asian adults: role of tibial plateau inclination. Knee 21:544–548PubMedCrossRefGoogle Scholar
  31. 31.
    Shrout PE, Fleiss JL (1979) Intraclass correlations: uses in assessing rater reliability. Psychol Bull 86:420–428PubMedCrossRefGoogle Scholar
  32. 32.
    Simpson DJ, Price AJ, Gulati A, Murray DW, Gill HS (2009) Elevated proximal tibial strains following unicompartmental knee replacement–a possible cause of pain. Med Eng Phys 31:752–757PubMedCrossRefGoogle Scholar
  33. 33.
    Squire MW, Callaghan JJ, Goetz DD, Sullivan PM, Johnston RC (1999) Unicompartmental knee replacement: a minimum 15 year followup study. Clin Orthop Relat Res 367:61–72PubMedCrossRefGoogle Scholar
  34. 34.
    Sva¨rd UC, Price AJ (2001) Oxford medial unicompartmental knee arthroplasty: a survival analysis of an independent series. J Bone Joint Surg Br 83:191–194CrossRefGoogle Scholar
  35. 35.
    ten Ham AM, Heesterbeek PJ, van der Schaaf DB, Jacobs WC, Wymenga AB (2013) Flexion and extension laxity after medial, mobile-bearing unicompartmental knee arthroplasty: a comparison between a spacer- and a tension-guided technique. Knee Surg Sports Traumatol Arthrosc 21:2447–2452PubMedCrossRefGoogle Scholar
  36. 36.
    Waldstein W, Bou Monsef J, Buckup J, Boettner F (2013) The value of valgus stress radiographs in the workup for medial unicompartmental arthritis. Clin Orthop Relat Res 471:3998–4003PubMedCrossRefGoogle Scholar
  37. 37.
    Whiteside LA (2005) Making your next unicompartmental knee arthroplasty last: three keys to success. J Arthroplasty 20(4 Suppl 2):2–3PubMedCrossRefGoogle Scholar
  38. 38.
    Zambianchi F, Digennaro V, Giorgini A, Grandi G, Fiacchi F, Mugnai R, Catani F (2014) Surgeon’s experience influences UKA survivorship: a comparative study between all-poly and metal back designs. Knee Surg Sports Traumatol Arthrosc. doi: 10.1007/s00167-014-2958-9 Google Scholar

Copyright information

© European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2014

Authors and Affiliations

  • Yasutaka Tashiro
    • 1
    Email author
  • Shuichi Matsuda
    • 2
  • Ken Okazaki
    • 1
  • Hideki Mizu-uchi
    • 1
  • Umito Kuwashima
    • 1
  • Yukihide Iwamoto
    • 1
  1. 1.Department of Orthopaedic Surgery, Graduate School of Medical SciencesKyushu UniversityFukuokaJapan
  2. 2.Department of Orthopaedic Surgery, Graduate School of MedicineKyoto UniversityKyotoJapan

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