Neutral or Natural? Functional Impact of the Coronal Alignment in Total Knee Arthroplasty

Abstract

Total knee arthroplasty (TKA) is a very successful procedure. The alignment in TKA has been identified as being of importance to prevent early implant failure and patient dissatisfaction. Our hypothesis was that patients with a preoperative varus deformation remaining in a slight varus alignment as their natural alignment after TKA will have superior clinical results compared with patients who are restored in neutral alignment. A total of 115 patients were corrected from varus to neutral (varus–neutral) and in 33 patients a preoperative varus alignment was kept in varus (varus). Standardized preoperative and postoperative full-length hip–knee–ankle radiographs under full weight-bearing conditions were performed in all patients. The patients' knees were categorized preoperatively and postoperatively based on the angle between mechanical femoral axis and mechanical tibial axis. Knees with alignment between ± 3 degrees were categorized as neutrally aligned, whereas alignment within ≤ –3 degrees was categorized as varus. The Knee Injury Osteoarthritis Outcome Score (KOOS) and Oxford Knee Score were determined retrospectively. The varus group scored significantly better in total KOOS (p < 0.05) compared with the varus–neutral group. Also, a trend was visible in the Oxford Knee Score but this was not significant (p > 0.05). This trend was even more evident in varus knees which were slightly undercorrected. The results support the assumption that leaving a residual varus alignment after TKA leads to better functional outcomes in TKA for patients with preoperative varus osteoarthritis.

Keywords

total knee arthroplasty - neutral alignment - varus alignment - total knee replacement

• References

• 1 Abdel MP, Morrey ME, Jensen MR, Morrey BF. Increased long-term survival of posterior cruciate-retaining versus posterior cruciate-stabilizing total knee replacements. J Bone Joint Surg Am 2011; 93 (22) 2072-2078
• 2 Seon JK, Song EK, Park SJ, Lee DS. The use of navigation to obtain rectangular flexion and extension gaps during primary total knee arthroplasty and midterm clinical results. J Arthroplasty 2011; 26 (04) 582-590
• 3 Choong PF, Dowsey MM, Stoney JD. Does accurate anatomical alignment result in better function and quality of life? Comparing conventional and computer-assisted total knee arthroplasty. J Arthroplasty 2009; 24 (04) 560-569
• 4 Lotke PA, Ecker ML. Influence of positioning of prosthesis in total knee replacement. J Bone Joint Surg Am 1977; 59 (01) 77-79
• 5 Lombardi Jr AV, Berend KR, Ng VY. Neutral mechanical alignment: a requirement for successful TKA: affirms. Orthopedics 2011; 34 (09) e504-e506
• 6 Parratte S, Pagnano MW, Trousdale RT, Berry DJ. Effect of postoperative mechanical axis alignment on the fifteen-year survival of modern, cemented total knee replacements. J Bone Joint Surg Am 2010; 92 (12) 2143-2149
• 7 Morgan SS, Bonshahi A, Pradhan N, Gregory A, Gambhir A, Porter ML. The influence of postoperative coronal alignment on revision surgery in total knee arthroplasty. Int Orthop 2008; 32 (05) 639-642
• 8 Dorr LD, Boiardo RA. Technical considerations in total knee arthroplasty. Clin Orthop Relat Res 1986; (205) 5-11
• 9 D'Lima DD, Hermida JC, Chen PC, Colwell Jr CW. Polyethylene wear and variations in knee kinematics. Clin Orthop Relat Res 2001; (392) 124-130
• 10 Jones CA, Voaklander DC, Johnston DW, Suarez-Almazor ME. Health related quality of life outcomes after total hip and knee arthroplasties in a community based population. J Rheumatol 2000; 27 (07) 1745-1752
• 11 Longstaff LM, Sloan K, Stamp N, Scaddan M, Beaver R. Good alignment after total knee arthroplasty leads to faster rehabilitation and better function. J Arthroplasty 2009; 24 (04) 570-578
• 12 Nishida K, Matsumoto T, Takayama K. , et al. Remaining mild varus limb alignment leads to better clinical outcome in total knee arthroplasty for varus osteoarthritis. Knee Surg Sports Traumatol Arthrosc 2017; 25 (11) 3488-3494
• 13 Vanlommel L, Vanlommel J, Claes S, Bellemans J. Slight undercorrection following total knee arthroplasty results in superior clinical outcomes in varus knees. Knee Surg Sports Traumatol Arthrosc 2013; 21 (10) 2325-2330
• 14 Becker R, Tandogan R, Violante B. Alignment in total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2016; 24 (08) 2393-2394
• 15 Meneghini RM, Grant TW, Ishmael MK, Ziemba-Davis M. Leaving residual varus alignment after total knee arthroplasty does not improve patient outcomes. J Arthroplasty 2017; 32 (9S) S171-S176
• 16 Insall JN, Binazzi R, Soudry M, Mestriner LA. Total knee arthroplasty. Clin Orthop Relat Res 1985; (192) 13-22
• 17 Fang DM, Ritter MA, Davis KE. Coronal alignment in total knee arthroplasty: just how important is it?. J Arthroplasty 2009; 24 (6, Suppl): 39-43
• 18 D'Lima DD, Chen PC, Colwell Jr CW. Polyethylene contact stresses, articular congruity, and knee alignment. Clin Orthop Relat Res 2001; (392) 232-238
• 19 Hungerford DS. Alignment in total knee replacement. Instr Course Lect 1995; 44: 455-468
• 20 Park A, Stambough JB, Nunley RM, Barrack RL, Nam D. The inadequacy of short knee radiographs in evaluating coronal alignment after total knee arthroplasty. J Arthroplasty 2016; 31 (04) 878-882
• 21 Magnussen RA, Weppe F, Demey G, Servien E, Lustig S. Residual varus alignment does not compromise results of TKAs in patients with preoperative varus. Clin Orthop Relat Res 2011; 469 (12) 3443-3450
• 22 Salzmann M, Fennema P, Becker R, Hommel H. Does postoperative mechanical axis alignment have an effect on clinical outcome of primary total knee arthroplasty? A retrospective cohort study. Open Orthop J 2017; 11: 1330-1336