KSSTA - 2026-05-22 - Journal Article
Prior anterior cruciate ligament reconstruction: Comparable outcomes but reduced knee flexion after robotic functionally aligned total knee arthroplasty.
Koutserimpas C, De Fazio A, Andriollo L, Gregori P, Servien E, Batailler C, Lustig S
Topics
Key Takeaway
Prior ACLR patients undergoing robotic functionally aligned TKA achieved equivalent KSS and FJS scores but had 10° less active knee flexion (120° vs. 130°, p=0.048) compared to controls at minimum 24-month follow-up.
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Summary
This retrospective comparative study asked whether prior ACLR compromises outcomes after image-based robotic-assisted TKA performed under functional alignment principles. KSS-knee (95 vs. 94), KSS-function (90 vs. 90), and FJS (83 vs. 86) were statistically equivalent between groups. Active knee flexion was significantly lower in the ACLR cohort (120° vs. 130°, p=0.048), with comparable complication rates (15.6% vs. 9.2%, p=0.18) and all-cause revision rates (2.2% vs. 1.5%, p=0.70).
Key Limitation
The ACLR group was significantly younger with lower BMI, and without multivariable adjustment these demographic differences—not the surgical approach—may explain the equivalent complication and revision rates.
Original Abstract
PURPOSE
Total knee arthroplasty (TKA) after anterior cruciate ligament reconstruction (ACLR) is technically demanding and has been associated with higher complication rates. This study aimed to evaluate whether patients with prior ACLR undergoing image-based robotic-assisted TKA performed under functional alignment (FA) principles achieve comparable clinical outcomes and early implant survivorship to patients undergoing primary TKA without previous ligament surgery.
METHODS
This retrospective comparative study (between March 2021 and December 2023) included consecutive patients who underwent image-based robotic-assisted TKA under FA principles with a minimum 24-month follow-up. Patients were divided into those with prior ACLR (study group) and those without previous ligament surgery (control group). Demographics, radiographic alignment, robotic implant positioning, knee society scores (KSS), forgotten joint score (FJS), active knee flexion, complications and all-cause revision rates were analysed. Kaplan-Meier survival analysis was performed.
RESULTS
A total of 383 TKAs were included (45 ACLR, 338 controls). Patients with prior ACLR were younger (62 vs. 70 years, p < 0.0001) and had lower BMI (25.34 vs. 28.32 kg/m², p < 0.0001). Postoperatively, KSS-knee (95 [interquartile range, IQR] 88-100) vs. 94 [90-100], p = 0.79], KSS-function (90 [89.5-100] vs. 90 [90-100], p = 0.82) and FJS (83 [63-94] vs. 86 [67-94], p = 0.80) were comparable between groups. Active knee flexion was lower in the ACLR group (120° [112.5-130] vs. 130° [120-130], p = 0.048). Overall complication rates were 15.6% versus 9.2% (p = 0.18). All-cause revision rates were 2.2% versus 1.5% (p = 0.70). Kaplan-Meier analysis demonstrated no difference in implant survivorship (HR = 1.62, 95% CI 0.13-19.57, p = 0.70).
CONCLUSION
Robotic-assisted TKA performed under FA principles provides comparable patient-reported outcomes and early implant survivorship in patients with prior ACLR and those undergoing standard primary TKA, although a modest reduction in postoperative knee flexion persists in the ACLR subgroup.
LEVEL OF EVIDENCE
Level III.