2017 ISAKOS Biennial Congress ePoster #1125
Analysis Of Anterior Tibial Subluxation To Femur At Maximum Extension In Anterior Cruciate Ligament-Deficient Knees
Kyohei Nishida, MD, Pittsburgh, pennsylvania UNITED STATES
Takehiko Matsushita, MD, Kobe, Hyogo JAPAN
Daisuke Araki, MD, PhD, Kobe, Hyogo JAPAN
Toshikazu Tanaka, MD, Kobe JAPAN
Nobuaki Miyaji, MD, Kobe, Hyogo JAPAN
Kazuyuki Ibaraki, MD, Kobe, Hyogo JAPAN
Noriyuki Kanzaki, MD, PhD, Kobe, Hyogo JAPAN
Ryosuke Kuroda, MD, PhD, Kobe, Hyogo JAPAN
Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, JAPAN
FDA Status Cleared
ACL reconstruction should be performed within 6 months after an injury to avoid the abnormal tibiofemoral relationship in the sagittal plane or at least within 12 months to avoid a complication of medial meniscal injuries.
It has been reported that anterior cruciate ligament (ACL) deficiency causes anterior tibial subluxation (ATS) to the femur. However, the factors affecting ATS associated with ACL deficiency is unknown. Therefore, this study aimed to assess the factors affecting ATS in ACL-deficient knees.
ATS to the femur was measured during maximum extension using fluoroscopy under general anesthesia in 123 isolated ACL-deficient knees. The true lateral view of the ACL-deficient-knee and the contralateral normal knee was obtained for measurement. First, a line was drawn from the peak anterior point (A) to the posterior point (B) of the medial tibial plateau. Next, a line was drawn perpendicular to the first line (A-B) from the anterior point of the Blumensaat’s line. The intersection of the two lines was defined as the point (C). A-C/A-B×100 % was defined as the ratio of ATS to the femur, and the side-to-side difference was evaluated. The patients were divided into four groups: Group 1 included 31 patients who underwent ACL reconstruction (ACLR) within 3 months after an injury. Group 2 included 46 patients who underwent ACLR between 3 months and 6 months after an injury. Group 3 included 27 patients who underwent ACLR between 6 months and 12 months after an injury. Group 4 included 19 patients who underwent ACLR more than 12 months after an injury. To identify the factors affecting ATS, following possible factors were assessed; (1) Time from injury to surgery (2) Medial meniscal injury (3) Tibial posterior slope. One-way analysis of variance was used for the comparison.
The mean side-to-side difference in the ratio of ATS to the femur was as follows: Group 1, 2.37 %; Group 2, 3.59 %; Group 3, 5.95 %; and Group 4, 8.45 %. Groups 3 and 4 showed significantly higher values than those of Groups 1 and 2. There was a positive correlation between the ratio of ATS and the time from injury to surgery (r = 0.52). The ratio of medial meniscus injury was significantly higher in Group 4 (Group 1, 29.0 %; Group 2, 23.9 %; Group 3, 29.6 %; and Group 4, 52.6 %). The ratio of ATS in patients who had a medial meniscus injury was significantly higher than that in the patients without medial meniscus injury (5.54 % vs 4.11 %; p < 0.001). There was no correlation between the ratio of ATS and the tibial posterior slope (r = 0.07).
ATS in maximum extension increases with time in ACL-deficient knees. In addition, medial meniscus injuries exacerbated ATS associated with ACL deficiency and medial meniscal injuries significantly increased 12 months after the ACL injury. Therefore, it is suggested that ACL reconstruction should be performed within 6 months after an injury if surgeons desire to avoid the abnormal tibiofemoral relationship in the sagittal plane at the time of the surgery or at least within 12 months to avoid a complication of medial meniscal injuries.