Sébastien Parratte1,2, Philippe Van Overschelde3, Marc Bandi4, Burak Yagmur Ozturk1, Cécile Batailler5. 1. Department of Orthopaedic Surgery, International Knee and Joint Centre, Abu Dhabi, United Arab Emirates. 2. Institute for Locomotion, Aix-Marseille University, Marseille, France. 3. Department of Orthopaedic Surgery, AZ Maria Middelares, Buitenring Sint-Denijs 30, 9000, Ghent, Belgium. 4. Zimmer, GmbH, Winterthur, Switzerland. 5. Department of Orthopaedic Surgery, Croix-Rousse Hospital, Lyon University Hospital, 103 Grande rue de la Croix Rousse, Lyon, France. cecile.batailler@chu-lyon.fr.
Abstract
PURPOSE: An anatomo-functional implant positioning (AFIP) technique in total knee arthroplasty (TKA) could restore physiological ligament balance (symmetric gap in extension, asymmetric gap in flexion). The purposes were to compare (1) ligament balancing in extension and flexion after TKA in the AFIP group, (2) TKA alignment, implant positioning and patellar tracking between AFIP and adjusted mechanical alignment (aMA) techniques, (3) clinical outcomes between both groups at 12 months. METHODS: All robotic-assisted TKA with an AFIP technique were included (n = 40). Exclusion criteria were genu valgum (HKA angle > 183°), extra-articular deformity more than 10°, and patellar maltracking (high-grade J-sign). One control patient with a TKA implanted by an aMA technique was matched for each case, based on age, body mass index, sex, and knee alignment. Ligament balancing (medial and lateral gaps in millimeters) in full extension and at 90° of flexion after TKA in the AFIP group was assessed with the robotic system. TKA alignment (HKA angle), implants positioning (femoral and tibial coronal axis, tibial slope, joint-line orientation), patellar tracking (patellar tilt and translation) and the Knee Society Score (KSS) at 6 and 12 months were compared between both groups. The ligament balancing was compared using a t test for paired samples in the AFIP group. The radiographic measurements and KSS scores were compared between groups using a t test for independent samples. RESULTS: In the AFIP group, there was no significant difference between the medial and lateral gap laxity in extension (NS). A significant opening of the lateral gap was observed in flexion compared to extension (mean: + 2.9 mm; p < 0.0001). The mean postoperative HKA angle was comparable between both groups (177.3° ± 2.1 in the AFIP group vs 176.8° ± 3.2; NS). In the AFIP group, the femoral anatomy was restored (90.9° ± 1.6) and the tibial varus was partially corrected (87.4° ± 1.8). The improvement of Knee and Function KSS at 6 months was better in the AFIP group (59.3 ± 11.9 and 51.7 ± 20, respectively, versus 49.3 ± 9.7 and 20.8 ± 13; p < 0.001). CONCLUSION: The AFIP concept allowed the restoration of the native knee alignment and a natural functional ligament pattern. With a more physiological target for ligament balancing, the AFIP technique had equivalent clinical outcomes at 12 months compared to aMA, with a faster recovery. LEVEL OF EVIDENCE: III retrospective therapeutic case control series.
PURPOSE: An anatomo-functional implant positioning (AFIP) technique in total knee arthroplasty (TKA) could restore physiological ligament balance (symmetric gap in extension, asymmetric gap in flexion). The purposes were to compare (1) ligament balancing in extension and flexion after TKA in the AFIP group, (2) TKA alignment, implant positioning and patellar tracking between AFIP and adjusted mechanical alignment (aMA) techniques, (3) clinical outcomes between both groups at 12 months. METHODS: All robotic-assisted TKA with an AFIP technique were included (n = 40). Exclusion criteria were genu valgum (HKA angle > 183°), extra-articular deformity more than 10°, and patellar maltracking (high-grade J-sign). One control patient with a TKA implanted by an aMA technique was matched for each case, based on age, body mass index, sex, and knee alignment. Ligament balancing (medial and lateral gaps in millimeters) in full extension and at 90° of flexion after TKA in the AFIP group was assessed with the robotic system. TKA alignment (HKA angle), implants positioning (femoral and tibial coronal axis, tibial slope, joint-line orientation), patellar tracking (patellar tilt and translation) and the Knee Society Score (KSS) at 6 and 12 months were compared between both groups. The ligament balancing was compared using a t test for paired samples in the AFIP group. The radiographic measurements and KSS scores were compared between groups using a t test for independent samples. RESULTS: In the AFIP group, there was no significant difference between the medial and lateral gap laxity in extension (NS). A significant opening of the lateral gap was observed in flexion compared to extension (mean: + 2.9 mm; p < 0.0001). The mean postoperative HKA angle was comparable between both groups (177.3° ± 2.1 in the AFIP group vs 176.8° ± 3.2; NS). In the AFIP group, the femoral anatomy was restored (90.9° ± 1.6) and the tibial varus was partially corrected (87.4° ± 1.8). The improvement of Knee and Function KSS at 6 months was better in the AFIP group (59.3 ± 11.9 and 51.7 ± 20, respectively, versus 49.3 ± 9.7 and 20.8 ± 13; p < 0.001). CONCLUSION: The AFIP concept allowed the restoration of the native knee alignment and a natural functional ligament pattern. With a more physiological target for ligament balancing, the AFIP technique had equivalent clinical outcomes at 12 months compared to aMA, with a faster recovery. LEVEL OF EVIDENCE: III retrospective therapeutic case control series.
Authors: Abdulaziz M Almaawi; Jonathan R B Hutt; Vincent Masse; Martin Lavigne; Pascal-Andre Vendittoli Journal: J Arthroplasty Date: 2017-02-20 Impact factor: 4.757
Authors: Jean-Noel Argenson; Sebastien Parratte; Abdullah Ashour; Richard D Komistek; Giles R Scuderi Journal: Clin Orthop Relat Res Date: 2008-08-15 Impact factor: 4.176