Anatomic Anterior Cruciate Ligament Reconstruction Using Hamstring Tendons Restores Quantitative Pivot Shift

Abstract

Background:It is still uncertain how surgical reconstruction of the anterior cruciate ligament (ACL) is able to restore rotatory laxity of the involved joint. The desired amount of restraint applied by the ACL graft, as compared with the healthy knee, has not been fully clarified.Purpose:To quantify the ability of single-bundle anatomic ACL reconstruction using hamstring tendons in reducing the pivot-shift phenomenon immediately after surgery under anesthesia.Study Design:Case series; Level of evidence, 4.Methods:An inertial sensor and image analysis were used at 4 international centers to measure tibial acceleration and lateral compartment translation of the knee, respectively. The standardized pivot-shift test was quantified in terms of the side-to-side difference in laxity both preoperatively and postoperatively with the patient under anesthesia. The reduction in both tibial acceleration and lateral compartment translation after surgery and the side-to-side difference were evaluated using the Wilcoxon signed-rank test. Alpha was set at P < .05.Results:A total of 107 patients were recruited for the study, and data were available for 89 patients. There was a statistically significant reduction in quantitative rotatory knee laxity between preoperatively (inertial sensor, 2.55 ± 4.00 m/s2; image analysis, 2.04 ± 2.02 mm) and postoperatively (inertial sensor, –0.54 ± 1.25 m/s2; image analysis, –0.10 ± 1.04 mm) between the involved and healthy joints, as measured by the 2 devices (P < .001 for both). Postoperatively, both devices detected a lower rotatory laxity value in the involved joint compared with the healthy joint (inertial sensor, 2.45 ± 0.89 vs 2.99 ± 1.10 m/s2, respectively [P < .001]; image analysis, 0.99 ± 0.83 vs 1.09 ± 0.92 mm, respectively [P = .38]).Conclusion:The data from this study indicated a significant reduction in the pivot shift when compared side to side. Both the inertial sensor and image analysis used for the quantitative assessment of the pivot-shift test could successfully detect restoration of the pivot shift after anatomic single-bundle ACL reconstruction. Future research will examine how pivot-shift control is maintained over time and correlation of the pivot shift with return to full activity in patients with an ACL injury.

Patient-Reported and Quantitative Outcomes of Anatomic Anterior Cruciate Ligament Reconstruction With Hamstring Tendon Autografts

“…As demonstrated previously, QPS measurements of anterior tibial translation and tibial acceleration were significantly reduced at time zero postoperatively with minimal side-to-side difference with regard to the contralateral healthy knee. 39 The QPS measurements preoperatively and at time zero after ACLR did not correlate with PROs at 24-month follow-up.…”

“…19,25,27 The pivot-shift test has been used both preoperatively and immediately postoperatively with the patient under anesthesia to assess rotatory knee laxity. 20,39 Although many factors, such as bony morphology and soft tissue injuries, 16,28,29,31,32 influence rotatory stability, anatomic single-bundle ACL reconstruction (ACLR) is effective in restoring rotational stability as measured by the pivot-shift test. 39 A persistent increased pivot shift after ACLR may be associated with an increased risk of cartilage and meniscal lesions.…”

“… 19 , 25 , 27 The pivot-shift test has been used both preoperatively and immediately postoperatively with the patient under anesthesia to assess rotatory knee laxity. 20 , 39 …”

“…Although many factors, such as bony morphology and soft tissue injuries, 16 , 28 , 29 , 31 , 32 influence rotatory stability, anatomic single-bundle ACL reconstruction (ACLR) is effective in restoring rotational stability as measured by the pivot-shift test. 39 A persistent increased pivot shift after ACLR may be associated with an increased risk of cartilage and meniscal lesions. 15 Moreover, a correlation between the pivot shift after ACLR and patient-reported instability has been demonstrated.…”

Anterior Cruciate Ligament Injury and the Anterolateral Complex of the Knee—Importance in Rotatory Knee Instability?

“…The primary goal of ACL reconstruction is to restore function to the knee, reducing the anterior tibial translation and rotatory knee instability seen in the ACL-deficient knee. While in most cases, anatomic reconstruction of the ACL reduces rotatory knee instability, the etiology of residual rotatory knee instability following anatomic ACL reconstruction remains unclear [62]. In this regard, residual rotatory knee instability or a highgrade pivot shift pre-operatively have been proposed as indications for ALC reconstruction [53,57].…”