An anatomo-functional implant positioning technique with robotic assistance for primary TKA allows the restoration of the native knee alignment and a natural functional ligament pattern, with a faster recovery at 6 months compared to an adjusted mechanical technique

Abstract

PurposeAn 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. MethodsAll 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. ResultsIn 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). ConclusionThe 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 evidenceIII retrospective therapeutic case control series.

Robotic‐arm assisted total knee arthroplasty is associated with comparable functional outcomes but improved forgotten joint scores compared with conventional manual total knee arthroplasty at five‐year follow‐up

“…Despite this, similar to the current study, the authors found no difference in KSS scores at one-year follow-up between RO TKA versus CO TKA. [33] Mitchell et al reviewed functional outcomes in 139 consecutive patients undergoing CO TKA versus 148 consecutive patients undergoing RO TKA, and also found comparable UCLA scores and Knee Injury and Osteoarthritis Outcome Scores (KOOS) at one-year follow-up [31]. Similar to the current study, the authors reported excellent clinical results with similar patient-reported outcomes in both treatment groups at one-year follow-up.…”

Gender‐specific distribution of knee morphology according to CPAK and functional phenotype classification: analysis of 8739 osteoarthritic knees prior to total knee arthroplasty using artificial intelligence

“…Consequently, when aiming for neutral alignment by using mechanical alignment approaches in TKA, the native joint orientation is inevitably modiied in many patients [2]. The results indicate the need in individualized alignment paradigms that adjust for variations in individual knee morphology, such as kinematic alignment or personalized alignment approaches [13,22,33,36,37]. BMI is another major factor in TKA failure, and even though we were able to identify a signiicant interaction between knee alignment and a high BMI, the efect was extremely small.…”

“…Consequently, when aiming for neutral alignment by using mechanical alignment approaches in TKA, the native joint orientation is inevitably modified in many patients [2]. The results indicate the need in individualized alignment paradigms that adjust for variations in individual knee morphology, such as kinematic alignment or personalized alignment approaches [13, 22, 33, 36, 37].…”

Personalized alignment™ for total knee arthroplasty using the ROSA® Knee and Persona® knee systems: Surgical technique

“…When combined with a modern medial congruent tibial implant, we believe the Personalized Alignment technique may improve patient satisfaction and clinical outcomes following TKA. A large meta-analysis of 1,112 cases reported greater Western Ontario and McMaster Universities Osteoarthritis (WOMAC) scores, Knee Society Score (KSS), flexion ROM, and walking distance for the KA technique compared to mechanical alignment ( 14 ), and a recent clinical retrospective study reported improved knee and function KSS scores at 6 months with a Personalized Alignment technique compared to non-robotic mechanically aligned TKA ( 26 ). Regarding the MC bearing, a meta-analysis ( 47 ) reported similar WOMAC and KSS, but improved forgotten joint scores with the MC bearing, and clinical studies have shown improved pain, satisfaction, and ROM with the MC compared to posterior stabilized components ( 48 , 49 ).…”

“…Compared to MA, faster recoveries ( 23 ), greater satisfaction rates ( 24 ), and higher outcome scores ( 25 ) have been reported for rKA procedures. On the other hand, personalized TKA requires technologic assistance as standard mechanical instrumentation is likely not accurate enough to achieve patient specific alignment ( 26 ). The ROSA ® Knee System is a semiactive robotic system that controls the placement of cutting jigs and allows the surgeon to use a preferred saw blade for bone resections and dynamic ligament balancing.…”