ACL rupture and joint laxity progression: a quantitative in vivo analysis.
OBJECTIVE
Benefits of an early reconstruction and the optimal time lapse between injury and surgery to reduce the effects of altered kinematics in ACL-deficient knees are still controversial.


OBJECTIVE
The aim of this study was to clarify, through a quantitative in vivo evaluation, the effects of the time lapse between ACL injury and surgery in terms of changes in the pre-operative knee laxity.


METHODS
An in vivo study was performed on 99 patients who underwent ACL surgery. Just before the graft fixation, six laxity tests were performed for all the subjects at manual-maximum load: anterior-posterior displacement and internal-external rotation at 30° and 90° of knee flexion (AP30, AP90, IE30, IE90) as well as varus-valgus rotation (VV0, VV30) at 0° and 30° of flexion. Kinematics data were acquired by a navigation system. The Spearman rank correlation was used to assess correlation between rank and continuous data. Significance was set at P = 0.05.


RESULTS
The analysis highlighted a significant influence of the injury-to-surgery time lapse on VV0 and AP90 compared with pre-operative laxity levels. Meniscus status also significantly affected the pre-operative laxity in the VV0 (Spearman's ρ = 0.203, P = 0.038; GLM with meniscal correction partial η = 0.27, P = 0.007) and AP90 (Spearman's ρ = 0.329, P = 0.001; GLM with meniscal correction partial η = 0.318, P = 0.017) tests.


CONCLUSIONS
The main finding of this study is that patients with ACL rupture and a higher injury-to-surgery time present higher values of knee laxity involving AP90 displacement and VV30 rotation. Clinical relevance of the study is that ACL-deficient joint laxity, involving anterior-posterior displacement at 90° of knee flexion and varus-valgus rotation at 0° of flexion, is significantly affected by the lapse of injury-to-surgery time. This highlights the importance of considering the effects of delaying surgery when managing patients with such deficiency.
Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Via Di Barbiano 1/10, 40136, Bologna, BO, Italy. c.signorelli@biomec.ior.it.
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Signorelli
Laboratorio Nano-Biotechnology NaBi, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.|Clinica Ortopedica e Traumatologica I, Istituto Ortopedico Rizzoli, Via Pupilli 1, 40136, Bologna, Italy.
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Filardo
Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Via Di Barbiano 1/10, 40136, Bologna, BO, Italy.|Clinica Ortopedica e Traumatologica I, Istituto Ortopedico Rizzoli, Via Pupilli 1, 40136, Bologna, Italy.
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Bonanzinga
Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Via Di Barbiano 1/10, 40136, Bologna, BO, Italy.|Clinica Ortopedica e Traumatologica I, Istituto Ortopedico Rizzoli, Via Pupilli 1, 40136, Bologna, Italy.
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Grassi
Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Via Di Barbiano 1/10, 40136, Bologna, BO, Italy.|Clinica Ortopedica e Traumatologica I, Istituto Ortopedico Rizzoli, Via Pupilli 1, 40136, Bologna, Italy.|Dipartimento di Scienze Biomediche e Neuromotorie DIBINEM, Univeristà di Bologna, Bologna, Italy.
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Zaffagnini
Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Via Di Barbiano 1/10, 40136, Bologna, BO, Italy.|Clinica Ortopedica e Traumatologica I, Istituto Ortopedico Rizzoli, Via Pupilli 1, 40136, Bologna, Italy.|Dipartimento di Scienze Biomediche e Neuromotorie DIBINEM, Univeristà di Bologna, Bologna, Italy.
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Marcacci
D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology* / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries / Q000150:complications / Q000503:physiopathology* / Q000601:surgery; D059549:Anterior Cruciate Ligament Reconstruction; D001696:Biomechanical Phenomena; D018450:Disease Progression; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology* / Q000601:surgery; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008592:Menisci, Tibial / Q000503:physiopathology; D016059:Range of Motion, Articular; D012399:Rotation; D000070600:Tibial Meniscus Injuries / Q000150:complications / Q000503:physiopathology; D013997:Time Factors; D055815:Young Adult
ACL injury; Laxity; Navigation; Time