Background: The use of hamstring tendons for anterior cruciate ligament reconstruction has increased in popularity over recent years. However, concerns with the stability of graft fixation on the tibial side remain. Centrally placed interference screw/sheath implants have demonstrated promising results in biomechanical studies.
Hypothesis: Centrally placed, polyethylene screw and sheath implants will provide clinically equivalent fixation to the standard metal interference screw and supplemental staple fixation.
Study Design: Randomized controlled trial; Level of evidence, 1.
Methods: A total of 113 consecutive patients undergoing isolated, unilateral, primary anterior cruciate ligament reconstruction with hamstring autografts were randomized to tibial fixation with metal interference screw and staples (RCI) or with a centrally placed polyethylene screw and sheath implant (INTRAFIX). Prospective assessment of subjective outcomes was performed using Lysholm, Mohtadi, and International Knee Documentation Committee (IKDC) scores.
Results: At minimum 2-year follow-up, there were no significant differences between the 2 groups in terms of instrumented stability testing (KT-1000 arthrometer) or subjective assessment of knee outcomes (IKDC, Lysholm, Mohtadi). Both fixation methods demonstrated a significant, but not different, increase in outcomes scores from preoperative to postoperative evaluation. There were 7 failures (5 INTRAFIX, 2 RCI) caused by reinjury, but no statistically significant differences were observed between the 2 fixation methods.
Conclusion: The centrally placed polyethylene screw and sheath provided equivalent clinical outcomes at minimum 2-year follow-up to standard tibial fixation with metal interference screw and staples.
Background: Minimal attention has been directed toward tibial tunnel position and the native tibial anterior cruciate ligament (ACL) footprint.
Purpose: To evaluate the effect of tibial tunnel position on restoration of knee kinematics and stability after ACL reconstruction.
Study Design: Controlled laboratory study.
Methods: Ten paired cadaveric knees were subjected to biomechanical testing (standardized Lachman and mechanized pivot-shift examination). With each maneuver, a computer-assisted navigation system recorded the 3-dimensional motion path of a tracked point at the center of the tibia, medial tibial plateau, and lateral tibial plateau. The testing protocol consisted of evaluation in the intact state and after complete ACL transection, after ACL transection with bilateral meniscectomy, and after ACL reconstruction using 3 tibial tunnel positions—over the top (OTT), anterior footprint (AT), and posterior footprint (PT)—with a standard femoral socket placed in the center of the femoral footprint. Repeated-measures analysis of variance with a post hoc Tukey test compared measured translations with each condition.
Results: A significant difference in anterior translation was seen with Lachman examination between the ACL-deficient condition and both the OTT and AT reconstructions, but no significant difference was observed between the ACL-deficient and PT reconstruction. The OTT and AT constructs were significantly better in limiting anterior translation of the lateral compartment compared with the PT ACL reconstruction during a pivot-shift maneuver in the ACL- and meniscal-deficient knee. However, anteriorizing the tibial position was accompanied by a correspondingly greater risk and magnitude of graft impingement in extension.
Clinical Relevance: The OTT and anterior tibial tunnel positions better control the Lachman and the pivot shift compared with an ACL graft placed in the posterior aspect of the tibial footprint. However, an anterior tibial tunnel position must be balanced against an increased risk and magnitude of graft impingement in extension.
Background: Although techniques and options for suitable graft substitutes for anterior cruciate ligament surgery continue to improve, failures occur because of many reasons. Errors in surgical techniques seem to be important reasons.
Hypothesis: Inappropriate positioning of the tunnels may be the most important reason for these failures. Anatomical anterior cruciate ligament revision reconstruction, using autografts, may yield acceptable outcomes.
Study design: Case series; Level of evidence, 4.
Methods: This retrospective study involved 148 anterior cruciate ligament revision reconstructions performed in our hospital using autografts. One hundred and seven patients were followed up at a mean of 72.9 ± 20.6 months. Clinical evaluation was performed using the Lysholm score, the Tegner rating system, the International Knee Documentation Committee evaluation form, and the KT-1000 arthrometer. Radiographs were evaluated for signs of osteoarthritis according to the Jaeger and Wirth classification.
Results: Inappropriate positioning of the tunnels was the most important reason (63.5%) for anterior cruciate ligament reconstruction failure. The average Lysholm score improved significantly at the follow-up (88.5 ± 12.4 vs 51.5 ± 24.9; P < .001). Moreover, the average Tegner activity score improved significantly compared with the activity score before revision surgery (6.3 ± 1.8 vs 2.8 ± 1.8; P < .001). The International Knee Documentation Committee score was A in 17 cases, B in 45, C in 37, and D in 8. Radiographic evaluation revealed that 33 patients had degenerative findings of grade I, 35 of grade II, 16 of grade III, and 2 of grade IV.
Conclusion: Anatomical anterior cruciate ligament revision reconstruction provides satisfactory midterm results as far as stability and function of the knee are concerned. In spite of these favorable subjective and objective results, the radiological evaluation revealed a significant progression of osteoarthritis.
