Previous cadaver studies showed that the additional bone cuts in the distal and posterior femur and joint line elevation resulted in laxity at mid-flexion after total knee arthroplasty (TKA). However, these results are not always applicable to TKA candidates because the related studies used cadaver knees with no osteoarthritis. It was hypothesized that the joint line elevation results in mid-flexion laxity after TKA in patients with knee osteoarthritis. The purpose of this study was to analyze the relationship between joint line elevation and mid-flexion laxity in patients with knee osteoarthritis.
30 knees with varus osteoarthritis undergoing TKA were evaluated. Two femoral trial component models were prepared: (1) normal model with a thickness of the distal and posterior femoral components of 9 mm, and (2) 2-mm joint line elevation model with a thickness of the distal and posterior femoral components of 9 − 2 = 7 mm. This 2-mm joint line elevation model simulated an additional bone cut in the distal and posterior femur, and joint line elevation, without an additional bone cut. The femoral trial component models were set before implantation and measured the joint gap kinematics using a tensor device through the full knee range of motion.
The differences in joint gap change from 30° to 90° were not statistically significant between the two models. However, the joint line elevation model decreased the joint gap laxity at 120° (p = 0.02) and at 145° (p = 0.01).
This study showed that a 2-mm joint line elevation was not associated with mid-flexion laxity in patients with varus osteoarthritis in the knee. The results of this study differed from the results in previous cadaver studies.
Level of evidence
Therapeutic study, level II, prospective comparative study.
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Dennis DA, Komistek RD, Kim RH, Sharma A (2010) Gap balancing versus measured resection technique for total knee arthroplasty. Clin Orthop Relat Res 468:102–107
Hino K, Ishimaru M, Iseki Y, Watanabe S, Onishi Y, Miura H (2013) Mid-flexion laxity is greater after posterior-stabilised total knee replacement than with cruciate-retaining procedures: a computer navigation study. Bone Joint J 95-B:493–497
Jennings LM, Bell CI, Ingham E, Komistek RD, Stone MH, Fisher J (2007) The influence of femoral condylar lift-off on the wear of artificial knee joints. Proc Inst Mech Eng H 221:305–314
Kettelkamp DB, Johnson RJ, Smidt GL, Chao EY, Walker M (1970) An electrogoniometric study of knee motion in normal gait. J Bone Joint Surg Am 52:775–790
Kim TK, Kwon SK, Kang YG, Chang CB, Seong SC (2010) Functional disabilities and satisfaction after total knee arthroplasty in female Asian patients. J Arthroplasty 25:458–464
Kurita M, Tomita T, Yamazaki T, Fujii M, Futai K, Shimizu N, Yoshikawa H, Sugamoto K (2012) In vivo kinematics of high-flex mobile-bearing total knee arthroplasty, with a new post-cam design, in deep knee bending motion. Int Orthop 36:2465–2471
Laubenthal KN, Smidt GL, Kettelkamp DB (1972) A quantitative analysis of knee motion during activities of daily living. Phys Ther 52:34–43
Le DH, Goodman SB, Maloney WJ, Huddleston JI (2014) Current modes of failure in TKA: infection, instability, and stiffness predominate. Clin Orthop Relat Res 472:2197–2200
Luyckx T, Vandenneucker H, Ing LS, Vereecke E, Ing AV, Victor J (2018) Raising the joint line in TKA is associated with mid-flexion laxity: a study in cadaver knees. Clin Orthop Relat Res 476:601–611
Martin JW, Whiteside LA (1990) The influence of joint line position on knee stability after condylar knee arthroplasty. Clin Orthop Relat Res 259:146–156
Matsuda S, Kawahara S, Okazaki K, Tashiro Y, Iwamoto Y (2013) Postoperative alignment and ROM affect patient satisfaction after TKA. Clin Orthop Relat Res 471:127–133
Minoda Y, Nakagawa S, Sugama R, Ikawa T, Noguchi T, Hirakawa M (2015) Midflexion laxity after implantation was influenced by the joint gap balance before implantation in TKA. J Arthroplasty 30:762–765
Minoda Y, Nakagawa S, Sugama R, Ikawa T, Noguchi T, Hirakawa M, Matsui Y, Nakamura H (2016) Decreased extension gap and valgus alignment after implantation of total knee prosthesis in primary varus knees. Knee Surg Sports Traumatol Arthrosc 24:3642–3647
Minoda Y, Iwaki H, Ikebuchi M, Yoshida T, Nakamura H (2012) The flexion gap preparation does not disturb the modified gap technique in posterior stabilized total knee arthroplasty. Knee 19:832–835
Minoda Y, Nakagawa S, Sugama R, Ikawa T, Noguchi T, Hirakawa M, Nakamura H (2014) Intraoperative assessment of midflexion laxity in total knee prosthesis. Knee 21:810–814
Minoda Y, Nakagawa S, Sugama R, Ikawa T, Noguchi T, Hirakawa M (2018) Joint gap in mid-flexion is not a predictor of postoperative flexion angle after total knee arthroplasty. J Arthroplasty 33:735–739
Schroer WC, Berend KR, Lombardi AV, Barnes CL, Bolognesi MP, Berend ME, Ritter MA, Nunley RM (2013) Why are total knees failing today? Etiology of total knee revision in 2010 and 2011. J Arthroplasty 28(8 suppl):116–119
The authors received no financial support for the research, authorship, and/or publication of this article.
Conflict of Interest
There is no conflict of interest.
This study was approved by the institutional review board of Osaka City University Graduate School of Medicine (ID number 1280).
All patients provided informed consent.
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Minoda, Y., Sugama, R., Ohta, Y. et al. Joint line elevation is not associated with mid-flexion laxity in patients with varus osteoarthritis after total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 28, 3226–3231 (2020). https://doi.org/10.1007/s00167-019-05828-1
- Total knee arthroplasty
- Joint line
- Mid-flexion laxity