The early outcome of kinematic versus mechanical alignment in total knee arthroplasty: a prospective randomised control trial

Bone Joint J. 2016 Oct;98-B(10):1360-1368. doi: 10.1302/0301-620X.98B10.36862.

Abstract

Aims: Our aim was to compare kinematic with mechanical alignment in total knee arthroplasty (TKA).

Patients and methods: We performed a prospective blinded randomised controlled trial to compare the functional outcome of patients undergoing TKA in mechanical alignment (MA) with those in kinematic alignment (KA). A total of 71 patients undergoing TKA were randomised to either kinematic (n = 36) or mechanical alignment (n = 35). Pre- and post-operative hip-knee-ankle radiographs were analysed. The knee injury and osteoarthritis outcome score (KOOS), American Knee Society Score, Short Form-36, Euro-Qol (EQ-5D), range of movement (ROM), two minute walk, and timed up and go tests were assessed pre-operatively and at six weeks, three and six months and one year post-operatively.

Results: A total of 78% of the kinematically aligned group (28 patients) and 77% of the mechanically aligned group (27 patients) were within 3° of their pre-operative plan. There were no statistically significant differences in the mean KOOS (difference 1.3, 95% confidence interval (CI) -9.4 to 12.1, p = 0.80), EQ-5D (difference 0.8, 95% CI -7.9 to 9.6, p = 0.84), ROM (difference 0.1, 95% CI -6.0 to 6.1, p = 0.99), two minute distance tolerance (difference 20.0, 95% CI -52.8 to 92.8, p = 0.58), or timed up and go (difference 0.78, 95% CI -2.3 to 3.9, p = 0.62) between the groups at one year.

Conclusion: Kinematically aligned TKAs appear to have comparable short-term results to mechanically aligned TKAs with no significant differences in function one year post-operatively. Further research is required to see if any theoretical long-term functional benefits of kinematic alignment are realised or if there are any potential effects on implant survival. Cite this article: Bone Joint J 2016;98-B:1360-8.

Keywords: Alignment; Function; Kinematic; Mechanical; Outcome; Total knee arthroplasty.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Arthroplasty, Replacement, Knee / methods*
  • Biomechanical Phenomena
  • Female
  • Humans
  • Knee Joint / diagnostic imaging
  • Knee Joint / physiopathology
  • Knee Joint / surgery*
  • Knee Prosthesis*
  • Male
  • Middle Aged
  • Osteoarthritis, Knee / diagnosis
  • Osteoarthritis, Knee / physiopathology
  • Osteoarthritis, Knee / surgery*
  • Postoperative Period
  • Prospective Studies
  • Prosthesis Design
  • Radiography
  • Range of Motion, Articular / physiology*
  • Recovery of Function*
  • Single-Blind Method
  • Young Adult