Restoring Tibial Slope and Sagittal Alignment of the Femoral Component in Unrestricted Kinematically Aligned Total Knee Arthroplasty Using Conventional versus Patient-Specific Instrumentation

Abstract

Restoring sagittal alignment in kinematically aligned (KA) total knee arthroplasty (TKA) is crucial to avoid patellofemoral joint instability or overstuffing and to restore an adequate range of motion. This prospective study compared the accuracy of conventional instrumentation (CI) versus patient-specific instrumentation (PSI) in restoring sagittal alignment of KA TKA measured by the tibial slope and degree of flexion of the femoral component to the sagittal femoral axis. One hundred patients were randomized to receive either CI (n = 50) or PSI (n = 50) for KA TKA. Two observers measured pre- and postoperative X-rays to assess restoration of the tibial slope and sagittal flexion. Inter- and intraclass correlations were calculated, and postoperative tibial and femoral components were compared with preoperative anatomy. In 50 CI patients, 86% (n = 43) had the tibial slope restored exactly, and no deviation more than 1 degree was found. Deviations of 0 to 1 degree were detected in 14% (n = 7). In 50 patients of the PSI group, 56% (n = 28) achieved an exact anatomic tibial slope restoration and 20% (n = 10) showed a deviation more than 2 degrees compared with the preoperative measurement. Deviations ranging between 0 to 1 and 1 to 2 degrees were found in 22% (n = 11) and 2% (n = 1) of cases, respectively. Sagittal alignment of the femoral component showed in both groups no deviation exceeding 1 degree. The restoration of sagittal alignment in KA TKA was statistically significantly differently distributed between CI and PSI (p = < 0.001) without clinical relevance. We found that PSI increased the odds for deviations >2 degrees in tibial slope reconstructions from 0 to 0.20 ([95% confidence interval: 0.09–0.31]; p = 0.001). Both CI and PSI revealed adequate results with respect to restoring sagittal alignment of the tibial and femoral components in KA TKA. The conventional technique requires adequate adjustment of the intramedullary rod to avoid hyperflexion of the femoral component and attention must be paid when restoring the tibial slope using PSI. This is a prospective Level II study.

Keywords

kinematic alignment - total knee arthroplasty - patient-specific instrumentation - conventional instrumentation - sagittal alignment - posterior tibial slope - femoral flexion

• References

• 1 Gromov K, Korchi M, Thomsen MG, Husted H, Troelsen A. What is the optimal alignment of the tibial and femoral components in knee arthroplasty?. Acta Orthop 2014; 85 (05) 480-487
• 2 Vendittoli PA, Martinov S, Blakeney WG. Restricted kinematic alignment, the fundamentals, and clinical applications. Front Surg 2021; 8: 697020
• 3 Bargren JH, Blaha JD, Freeman MA. Alignment in total knee arthroplasty. Correlated biomechanical and clinical observations. Clin Orthop Relat Res 1983; (173) 178-183
• 4 Bellemans J, Colyn W, Vandenneucker H, Victor J. The Chitranjan Ranawat award: is neutral mechanical alignment normal for all patients? The concept of constitutional varus. Clin Orthop Relat Res 2012; 470 (01) 45-53
• 5 Benjamin J. Component alignment in total knee arthroplasty. Instr Course Lect 2006; 55: 405-412
• 6 Berend ME, Ritter MA, Meding JB. et al. Tibial component failure mechanisms in total knee arthroplasty. Clin Orthop Relat Res 2004; (428) 26-34
• 7 Lotke PA, Ecker ML. Influence of positioning of prosthesis in total knee replacement. J Bone Joint Surg Am 1977; 59 (01) 77-79
• 8 Park JK, Seon JK, Cho KJ, Lee NH, Song EK. Is immediate postoperative mechanical axis associated with the revision rate of primary total knee arthroplasty? A 10-year follow-up study. Clin Orthop Surg 2018; 10 (02) 167-173
• 9 Abdel MP, Ollivier M, Parratte S, Trousdale RT, Berry DJ, Pagnano MW. Effect of postoperative mechanical axis alignment on survival and functional outcomes of modern total knee arthroplasties with cement: a concise follow-up at 20 years. J Bone Joint Surg Am 2018; 100 (06) 472-478
• 10 Howell SM. Calipered kinematically aligned total knee arthroplasty: an accurate technique that improves patient outcomes and implant survival. Orthopedics 2019; 42 (03) 126-135
• 11 Brar AS, Howell SM, Hull ML, Mahfouz MR. Does kinematic alignment and flexion of a femoral component designed for mechanical alignment reduce the proximal and lateral reach of the trochlea?. J Arthroplasty 2016; 31 (08) 1808-1813
• 12 Howell SM, Shelton TJ, Hull ML. Implant survival and function ten years after kinematically aligned total knee arthroplasty. J Arthroplasty 2018; 33 (12) 3678-3684
• 13 Ettinger M, Calliess T, Howell SM. Does a positioning rod or a patient-specific guide result in more natural femoral flexion in the concept of kinematically aligned total knee arthroplasty?. Arch Orthop Trauma Surg 2017; 137 (01) 105-110
• 14 Klasan A, de Steiger R, Holland S, Hatton A, Vertullo CJ, Young SW. Similar risk of revision after kinematically aligned, patient-specific instrumented total knee arthroplasty, and all other total knee arthroplasty: combined results from the Australian and New Zealand Joint Replacement Registries. J Arthroplasty 2020; 35 (10) 2872-2877
• 15 Hirschmann MT, Becker R, Tandogan R, Vendittoli PA, Howell S. Alignment in TKA: what has been clear is not anymore!. Knee Surg Sports Traumatol Arthrosc 2019; 27 (07) 2037-2039
• 16 Nisar S, Palan J, Rivière C, Emerton M, Pandit H. Kinematic alignment in total knee arthroplasty. EFORT Open Rev 2020; 5 (07) 380-390
• 17 Mattei L, Pellegrino P, Calò M, Bistolfi A, Castoldi F. Patient specific instrumentation in total knee arthroplasty: a state of the art. Ann Transl Med 2016; 4 (07) 126
• 18 Smolle MA, Koutp A, Clar C, Leitner L, Leithner A, Sadoghi P. Restoring tibial obliquity for kinematic alignment in total knee arthroplasty: conventional versus patient-specific instrumentation. Arch Orthop Trauma Surg 2023; 143 (09) 5867-5872
• 19 Koch PP, Müller D, Pisan M, Fucentese SF. Radiographic accuracy in TKA with a CT-based patient-specific cutting block technique. Knee Surg Sports Traumatol Arthrosc 2013; 21 (10) 2200-2205
• 20 Ni QK, Song GY, Zhang ZJ, Zheng T, Cao YW, Zhang H. Posterior tibial slope measurements based on the full-length tibial anatomic axis are significantly increased compared to those based on the half-length tibial anatomic axis. Knee Surg Sports Traumatol Arthrosc 2022; 30 (04) 1362-1368
• 21 Tsukeoka T, Lee TH. Sagittal flexion of the femoral component affects flexion gap and sizing in total knee arthroplasty. J Arthroplasty 2012; 27 (06) 1094-1099
• 22 Calliess T, Bauer K, Stukenborg-Colsman C, Windhagen H, Budde S, Ettinger M. PSI kinematic versus non-PSI mechanical alignment in total knee arthroplasty: a prospective, randomized study. Knee Surg Sports Traumatol Arthrosc 2017; 25 (06) 1743-1748
• 23 Dossett HG, Estrada NA, Swartz GJ, LeFevre GW, Kwasman BG. A randomised controlled trial of kinematically and mechanically aligned total knee replacements: two-year clinical results. Bone Joint J 2014; 96-B [phone]
• 24 Waterson HB, Clement ND, Eyres KS, Mandalia VI, Toms AD. The early outcome of kinematic versus mechanical alignment in total knee arthroplasty: a prospective randomised control trial. Bone Joint J 2016; 98-B (10) 1360-1368
• 25 Howell SM, Howell SJ, Kuznik KT, Cohen J, Hull ML. Does a kinematically aligned total knee arthroplasty restore function without failure regardless of alignment category?. Clin Orthop Relat Res 2013; 471 (03) 1000-1007
• 26 Eckhoff DG, Bach JM, Spitzer VM. et al. Three-dimensional mechanics, kinematics, and morphology of the knee viewed in virtual reality. J Bone Joint Surg Am 2005; 87 (Suppl. 02) 71-80
• 27 Howell SM, Papadopoulos S, Kuznik KT, Hull ML. Accurate alignment and high function after kinematically aligned TKA performed with generic instruments. Knee Surg Sports Traumatol Arthrosc 2013; 21 (10) 2271-2280x
• 28 Courtney PM, Lee GC. Early outcomes of kinematic alignment in primary total knee arthroplasty: a meta-analysis of the literature. J Arthroplasty 2017; 32 (06) 2028-2032.e1
• 29 Nedopil AJ, Howell SM, Hull ML. What clinical characteristics and radiographic parameters are associated with patellofemoral instability after kinematically aligned total knee arthroplasty?. Int Orthop 2017; 41 (02) 283-291
• 30 Singh G, Tan JH, Sng BY, Awiszus F, Lohmann CH, Nathan SS. Restoring the anatomical tibial slope and limb axis may maximise post-operative flexion in posterior-stabilised total knee replacements. Bone Joint J 2013; 95-B (10) 1354-1358
• 31 Catani F, Leardini A, Ensini A. et al. The stability of the cemented tibial component of total knee arthroplasty: posterior cruciate-retaining versus posterior-stabilized design. J Arthroplasty 2004; 19 (06) 775-782
• 32 Adıyeke L, Kafadar AB, Erdoğan Ö, Gündüz ÇD. The effect of tibial slope angle on clinical and functional results after mobile bearing total knee arthroplasty. J Orthop Trauma Rehab 2022; 29 (01) 221049172210758