Evaluation of the TruMatch® System in Knee Prosthetic Surgery

Patient specific instrumentation is an alternative to conventional intra- and extra-medullary guides to perform the femoral and tibial cuts in total knee replacement (TKR). This instrumentation could provide a better alignment of a TKR, reduce blood losses and operative time, and improve clinical outcomes. The primary goal of this study is to compare the femorotibial mismatch angle of two groups of patients: patients undergoing posterior stabilized, fixed bearing TKR with conventional Attune® instrumentation (DePuy Johnson & Johnson, Warsaw, Indiana), versus patient undergoing TKR with the TruMatch® (DePuy Johnson & Johnson, Warsaw, Indiana) cutting guide.

Good alignment after a TKR leads to faster rehabilitation, better clinical outcomes and lower revision rate. A correct rotational (axial) alignment reduces patellofemoral complications, polyethylene wear and unexplained knee pain. A randomized controlled study is conducted to test if to use the TruMatch® (DePuy Johnson & Johnson, Warsaw, Indiana) patient specific instrumentation reduces the number of patients presenting femorotibial mismatch. Secondary goals are to compare: alignment in the coronal, sagittal and axial plane of the femoral component; alignment in the coronal and sagittal plane of the tibial component; number of recuts during surgery and surgeon's adherence to planning; blood loss; clinical outcome after two months using the Oxford Knee Score (OKS). After having signed informed consent, patients will be randomized in 2 groups preoperatively. A long-leg CT scan, according to manufacturer's instructions, will be performed on patients randomized to the TruMatch® group. Haemoglobin and haematocrit will be recorded pre- and postoperatively. Two months after surgery a knee CT-scan, anteroposterior and laterolateral scanograms will be performed on all patients, and OKS will be recorded.

In patients randomized to experimental arm, TKR components will be implanted using TruMatch® patient specific cutting guides.

In patients randomized to control arm, TKR components will be implanted using Attune® instrumentation (femoral intra-medullary guide, tibial extra-medullary guide), without TruMatch® patient specific cutting guides.

Angle between the posterior femoral condylar plane and the plane passing trough the posterior end of the tibial keel (measured on axial CT-scan).

Coronal limb alignment, alignment in the coronal, sagittal and axial plane of the femoral component and alignment in the coronal and sagittal plane of the tibial component will be measured using a knee CT-scan, anteroposterior and laterolateral scanograms.

Inclusion Criteria: Age > 40, <80 Indication for TKR Surgical indication for Attune®, posterior stabilized, fixed bearing TKR Patients signed written informed consent Exclusion Criteria: Age > 80, < 40 TKR revision surgery Metal devices within 8 cm from knee articular surfaces Fixed knee deformities greater than 15° in varus, valgus, flexion or tibial slope. Knee ankylosis Previous tibial osteotomy surgery Informed consent not accepted Serious comorbidity Active infections Pregnant or breastfeeding women

Unità Operativa Ortopedia II, Policlinico San Donato (Istituto di Ricovero e Cura a Carattere Scientifico)

Fang DM, Ritter MA, Davis KE. Coronal alignment in total knee arthroplasty: just how important is it? J Arthroplasty. 2009 Sep;24(6 Suppl):39-43. doi: 10.1016/j.arth.2009.04.034. Epub 2009 Jun 24.

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 Jun;24(4):570-8. doi: 10.1016/j.arth.2008.03.002. Epub 2008 May 19.

Nunley RM, Ellison BS, Zhu J, Ruh EL, Howell SM, Barrack RL. Do patient-specific guides improve coronal alignment in total knee arthroplasty? Clin Orthop Relat Res. 2012 Mar;470(3):895-902. doi: 10.1007/s11999-011-2222-2. Epub 2011 Dec 20. Erratum In: Clin Orthop Relat Res. 2012 Apr;470(4):1242.

Chauhan SK, Clark GW, Lloyd S, Scott RG, Breidahl W, Sikorski JM. Computer-assisted total knee replacement. A controlled cadaver study using a multi-parameter quantitative CT assessment of alignment (the Perth CT Protocol). J Bone Joint Surg Br. 2004 Aug;86(6):818-23. doi: 10.1302/0301-620x.86b6.15456.

Bell SW, Young P, Drury C, Smith J, Anthony I, Jones B, Blyth M, McLean A. Component rotational alignment in unexplained painful primary total knee arthroplasty. Knee. 2014 Jan;21(1):272-7. doi: 10.1016/j.knee.2012.09.011. Epub 2012 Nov 7.

Rienmuller A, Guggi T, Gruber G, Preiss S, Drobny T. The effect of femoral component rotation on the five-year outcome of cemented mobile bearing total knee arthroplasty. Int Orthop. 2012 Oct;36(10):2067-72. doi: 10.1007/s00264-012-1628-0. Epub 2012 Aug 1.

Heyse TJ, Tibesku CO. Improved femoral component rotation in TKA using patient-specific instrumentation. Knee. 2014 Jan;21(1):268-71. doi: 10.1016/j.knee.2012.10.009. Epub 2012 Nov 8.

Randelli PS, Menon A, Pasqualotto S, Zanini B, Compagnoni R, Cucchi D. Patient-Specific Instrumentation Does Not Affect Rotational Alignment of the Femoral Component and Perioperative Blood Loss in Total Knee Arthroplasty: A Prospective, Randomized, Controlled Trial. J Arthroplasty. 2019 Jul;34(7):1374-1381.e1. doi: 10.1016/j.arth.2019.03.018. Epub 2019 Mar 13.