2017 ISAKOS Biennial Congress ePoster #1156
Relationship between Preoperative Knee Laxity and Postoperative Positive Pivot Shift in ACL Reconstruction
Yuji Yamamoto, MD, Hirosaki, Aomori JAPAN
Eiichi Tsuda, Prof., Hirosaki, Aomori JAPAN
Shugo Maeda, MD, Hachinohe, Aomori JAPAN
Takuya Naraoka, MD, Fujinomiya, Shizuoka JAPAN
Yuka Kimura, MD, Hirosaki, Aomori JAPAN
Yasuyuki Ishibashi, MD, Hirosaki, Aomori JAPAN
Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, JAPAN
FDA Status Not Applicable
ACL injuries with large knee laxity has a higher risk of positive pivot shift
Positive pivot shift is reported to correlate with symptoms of giving way, functional disability and less satisfaction with treatment outcome, and is thought to be a predictor of later osteoarthritis after ACL reconstruction. Therefore, it is important to determine which preoperative factors (knee laxity etc.) are related to postoperative pivot shift result. The purpose of this study was to investigate the relationship between preoperative knee laxity and postoperative positive pivot shift in ACL reconstruction.
Fifty-one patients (22 males, 19 females; average age: 23.8 years old) who underwent primary ACL reconstruction (double-bundle with hamstrings graft in 38 knees, single-bundle with rectangular BTB graft in 13 knees) were investigated. Preoperative knee laxity was evaluated using a navigation system, including anterior tibial translation (ATT) with the Lachman test and posterior tibial reduction (PTR) during pivot shift test. Preoperative knee laxity were compared between patients with a negative pivot shift and those with a positive pivot shift at 1 year after surgery. Multiple logistic regression analysis (dependent variable: postoperative pivot shift results, independent variable: age, gender, BMI, graft selection, ATT, PTR) was performed. The cut-off value of preoperative ATT predicting patients at increased risk of positive pivot shift was evaluated by ROC curve analysis.
In preoperative evaluation using a navigation system, average ATT was 12.1 ± 2.9 mm and positive pivot shift was confirmed in all patients, with an average PTR of 5.2 ± 2.7 mm. After reconstruction, the pivot shift phenomenon disappeared in all patients. At 1 year follow-up, side-to-side difference with KT1000 was 0.5 ± 0.7 mm with 4 of 51 patients having a positive pivot shift (positive rate 7.8%). Preoperative ATT in the positive pivot shift group was significantly larger than that in the negative pivot shift group (p=0.015), whereas no significant difference was found in PTR between the two groups. Multiple logistic regression analysis showed that only preoperative ATT was associated with postoperative positive pivot shift (Odds ratio=2.35, 95%CI 1.09-5.46). AUC was 0.87 (95% CI: 0.66-1.00, p=0.019) when the cut-off value of preoperative ATT was 14.5mm with sensitivity of 75.0% and specificity of 99.1%.
The present study demonstrated that patients with positive pivot shift 1 year after ACL reconstruction had preoperatively large ATT and that ACL injuries with large ATTs had a higher risk of positive pivot shift. In cases with large knee laxity, a strategy to prevent the pivot shift phenomenon may be needed.