Biomechanical analysis of a combined double-bundle posterior cruciate ligament and posterolateral corner reconstruction.
ABSTRACT Failure to address both components of a combined posterior cruciate ligament and posterolateral corner injury has been implicated as a reason for abnormal biomechanics and inferior clinical results.
Combined double-bundle posterior cruciate ligament and posterolateral corner reconstruction restores the kinematics and in situ forces of the intact knee ligaments.
Controlled laboratory study.
Ten fresh-frozen human cadaveric knees were tested using a robotic testing system through sequential cutting and reconstructing of the posterior cruciate ligament and posterolateral corner. The knees were subjected to a 134-N posterior tibial load and a 5-N.m external tibial torque at multiple flexion angles. The double-bundle posterior cruciate ligament reconstruction was performed using Achilles and semitendinosus tendons. The posterolateral corner reconstruction consisted of reattaching the popliteus tendon to its femoral origin and reconstructing the popliteofibular ligament with a gracilis tendon.
Under the posterior load, the combined reconstruction reduced posterior translation to within 1.2 +/- 1.5 mm of the intact knee. The in situ forces in the posterior cruciate ligament grafts were significantly less than those in the native posterior cruciate ligament at all angles except full extension. Conversely, the forces in the posterolateral corner grafts were significantly higher than those in the native structures at all angles. Under the external torque with the combined reconstruction, external rotation as well as in situ forces in the posterior cruciate ligament and posterolateral corner grafts were not different from the intact knee.
A combined posterior cruciate ligament and posterolateral corner reconstruction can restore intact knee kinematics at time zero. In situ forces in the intact posterior cruciate ligament and posterolateral corner were not reproduced by the reconstruction; however, the posterolateral corner reconstruction reduced the loads experienced by the posterior cruciate ligament grafts.
By addressing both structures of this combined injury, this technique restores native kinematics under the applied loads at fixed flexion angles and demonstrates load sharing among the grafts creating a potentially protective effect against early failure of the posterior cruciate ligament grafts but with increased force in the posterolateral corner construct.
- SourceAvailable from: Patrick Djian[Show abstract] [Hide abstract]
ABSTRACT: Posterior cruciate ligament (PCL) injuries are frequently associated with posterolateral corner (PLC) damages. These complex lesions are most often poorly tolerated clinically. Adherence to sound biomechanical principles treating these complex lesions entails obtaining a functional PCL and reconstructing sufficient posterolateral stability. Surgical treatment of postero-posterolateral laxity (PPLL) re-establishes sufficient anatomical integrity to provide stability and satisfactory knee function. In this retrospective, continuous, single-operator study, 21 patients were operated for chronic PPLL with combined reconstruction of the PCL and PLC and were reviewed with a minimum 1 year follow-up. The clinical and subjective outcomes were evaluated using the IKDC score. Surgical correction of posterior laxity was quantified clinically and radiologically on dynamic posterior drawer images (posterior Telos stress test and hamstrings contraction lateral view). The mean subjective IKDC score was 62.8 at the last follow-up versus a preoperative score of 54.5 (NS). Preoperatively, all were classified in groups C and D. Postoperatively, 13 patients out of 21 were classified in groups A and B according to the overall clinical IKDC score. The radiological gain in laxity was 51% on the hamstring contraction films and 67% on the posterior Telos images (p<0.05). The objective of surgical treatment is to re-establish anatomical integrity to the greatest possible extent. The clinical and radiological laxity results are disappointing in terms of the objectives but are in agreement with the literature. The subjective evaluation demonstrated that this operation can provide sufficient function for standard daily activities but not sports activities. Level IV retrospective study.Orthopaedics & Traumatology Surgery & Research 05/2010; 96(4):394-9. DOI:10.1016/j.otsr.2010.02.007 · 1.17 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: This paper is addressed to the problem of robust stabilization of imprecisely known linear time-invariant (LTI) plants, using nonlinear time-varying (NLTV) controllers. We consider a general family of LTI plants described by a nominal plant model with unstructured uncertainty, and show that a necessary and sufficient condition for such a family to be robustly stabilizable (by an arbitrary NLTV controller) is that it be robustly stabilizable by an LTI controller.Decision and Control, 1986 25th IEEE Conference on; 01/1986
- [Show abstract] [Hide abstract]
ABSTRACT: The treatment of posterior cruciate ligament (PCL) injuries remains controversial. The ideal choice of graft and reconstructive technique remains uncertain. A bifid bone-patellar tendon-bone allograft is described that is suitable for either arthroscopic transtibial tunnel or open tibial inlay reconstruction of the posterior cruciate ligament. This graft closely recreates the anatomic configuration and size of the native posterior cruciate ligament. Testing of this graft versus a single bundle construct showed improved biomechanical performance in a tibial inlay PCL reconstruction. When posterior cruciate ligament reconstruction is indicated, a double-bundle reconstruction effectively restores normal knee kinematics. We describe our clinical experience with this technique for PCL reconstruction with our active-duty military population.Operative Techniques in Sports Medicine 10/2005; 13(4):233-240. DOI:10.1053/j.otsm.2006.01.009 · 0.21 Impact Factor