Tibial Internal-external Rotation Research Articles

A Comparison of 11 O'clock versus Oblique Femoral Tunnels in the Anterior Cruciate Ligament—Reconstructed Knee

Background Traditionally, a standard femoral tunnel for a single-bundle anterior cruciate ligament (ACL) reconstruction is positioned 6 to 7 mm anterior to the posterior wall at an 11 o'clock orientation in the femoral notch (right knee). However, some surgeons have advocated placing the femoral tunnel at a more oblique orientation at or near the femoral footprint of the ACL's posterolateral bundle (at approximately 9:30 to 10 o'clock in the notch) to provide the graft with a better mechanical advantage for controlling tibial rotation and eliminating the pivot shift. Hypothesis Moving the femoral tunnel from the standard location to an oblique position in the femoral notch will significantly reduce the magnitude of a simulated pivot shift. Study Design Controlled laboratory study. Methods Internal-external tibial rotation and anteroposterior (AP) displacement of the lateral tibial plateau were measured in 17 fresh-frozen cadaveric knees during a simulated pivot-shift event with a single-bundle ACL reconstruction placed in standard and oblique femoral tunnels. Baseline kinematic measurements were taken with the graft tensioned to restore intact AP knee laxity at 30° of flexion. The measurements were repeated as graft tension was decreased to produce approximately 2-mm incremental increases in laxity (up to +10 mm). Correlations between lateral tibial plateau displacement and tibial rotation during the pivot shift were determined for both tunnels. Results There were no significant differences in tibial rotations or tibial plateau displacements during the pivot shift between standard and oblique femoral tunnels when the graft was tensioned to restore intact knee laxity. The relationship between pivot-shift magnitude and AP laxity was highly linear for each knee specimen over the range of laxities tested; the mean slopes for anteromedial (AM) and posterolateral (PL) tunnels were not significantly different. There were near perfect linear correlations (mean r2 > .98) between lateral plateau displacement and tibial rotation for both femoral tunnel positions; the slope of the regression line was not significantly different between tunnels. Conclusion Moving the femoral tunnel from the standard location to a more oblique position in the notch did not significantly alter pivot-shift kinematics. Lateral plateau displacement was strongly correlated with tibial rotation, and either can be used to quantify the pivot shift. Clinical Relevance The rationale for placing the femoral tunnel at an oblique position in the notch to reduce the pivot shift is questioned.

The Effect of Anterior Cruciate Ligament Reconstruction on Kinematics of the Knee With Combined Anterior Cruciate Ligament Injury and Subtotal Medial Meniscectomy: An In Vitro Robotic Investigation

The aims of this study were to determine: (1) the kinematic effect of subtotal medial meniscectomy on the anterior cruciate ligament (ACL)-deficient knee and (2) the effect of ACL reconstruction on kinematics of the knee with combined ACL deficiency and subtotal medial meniscectomy under anterior tibial and simulated quadriceps loads. Eight human cadaveric knees were sequentially tested using a robotic testing system under 4 conditions: intact, ACL deficiency, ACL deficiency with subtotal medial meniscectomy, and single-bundle ACL reconstruction using a bone-patellar tendon-bone graft. Knee kinematics were measured at 0 degrees, 15 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion under an anterior tibial load of 130 N and a quadriceps muscle load of 400 N. Subtotal medial meniscectomy in the ACL-deficient knee significantly increased anterior and lateral tibial translations under the anterior tibial and quadriceps loads (P < .05). These kinematic changes were larger at high flexion (>or=60 degrees) than at low flexion angles. ACL reconstruction in knees with ACL deficiency and subtotal medial meniscectomy significantly reduced the increased anterior tibial translation, but could not restore anterior translation to the intact level with differences ranging from 2.6 mm at 0 degrees to 5.5 mm at 30 degrees of flexion. ACL reconstruction did not significantly affect the medial-lateral translation and internal-external tibial rotation in the presence of subtotal meniscectomy. Subtotal medial meniscectomy in knees with ACL deficiency altered knee kinematics, especially at high flexion angles. ACL reconstruction significantly reduced the increased tibial translation in knees with combined ACL deficiency and subtotal medial meniscectomy, but could not restore the knee kinematics to the intact knee level. This study suggests that meniscus is an important secondary stabilizer against anterior and lateral tibial translations and should be preserved in the setting of ACL reconstruction for restoration of optimal knee kinematics and function.

Validation of a non-invasive fluoroscopic imaging technique for the measurement of dynamic knee joint motion

The accurate measurement of the in vivo knee joint kinematics in six degrees-of-freedom (6DOF) remains a challenge in biomedical engineering. We have adapted a dual fluoroscopic imaging system (DFIS) to investigate the various in vivo dynamic knee joint motions. This paper presents a thorough validation of the accuracy and repeatability of the DFIS system when used to measure 6DOF dynamic knee kinematics. First, the validation utilized standard geometric spheres made from different materials to demonstrate the capability of the DFIS technique to determine the object positions under changing speeds. The translational pose of the spheres could be recreated to less than 0.15±0.09 mm for velocities below 300 mm/s. Next, tantalum beads were inserted into the femur and tibia of two fresh frozen cadaver knees to compare the dynamic kinematics measured by matching knee models to the kinematics from the tantalum bead matching—a technique similar to Roentgen stereophotogrammetric analysis (RSA). Each cadaveric knee was attached to the crosshead of a tensile testing machine and vertically translated at a rate of 16.66 mm/s while images were captured with the DFIS. Subsequently, the tibia was held fixed and the femur manually flexed from full extension to 90° of flexion, as the DFIS acquired images. In vitro translation of the cadaver knee using the tensile testing machine deviated from predicted values by 0.08±0.14 mm for the matched knee models. The difference between matching the knee and tantalum bead models during the dynamic flexion–extension motion of the knee was 0.1±0.65°/s in flexion speed; 0.24±0.16 mm in posterior femoral translation; and 0.16±0.61° in internal–external tibial rotation. Finally, we applied the method to investigate the knee kinematics of a living subject during a step ascent and treadmill gait. High repeatability was demonstrated for the in vivo application. Thus, the DFIS provides an easy and powerful tool for accurately determining 6DOF positions of the knee when performing daily functional activities.

Effectiveness of Reconstruction of the Anterior Cruciate Ligament with Quadrupled Hamstrings and Bone-Patellar Tendon-Bone Autografts

Background The 2 most frequently used autografts for anterior cruciate ligament reconstruction are the bone-patellar tendon-bone and the quadrupled hamstrings tendon. Hypothesis Hamstring tendon graft is superior to patellar tendon graft in restoring tibial rotation during highly demanding activities because of its superiority in strength and linear stiffness and because it is closer morphologically to the anatomy of the natural anterior cruciate ligament. Study Design Case control study; Level of evidence, 3. Methods Eleven patients with patellar tendon graft anterior cruciate ligament reconstruction, 11 patients with hamstring tendon graft anterior cruciate ligament reconstruction, and 11 controls were assessed. Kinematic data were collected (50 Hz) with a 6-camera optoelectronic system while the subjects descended stairs and, immediately after, pivoted on their landing leg. The dependent variable examined was the tibial internal-external rotation during pivoting. All patients in both groups were also assessed clinically and with the use of a KT-1000 arthrometer to evaluate anterior tibial translation. Results The results demonstrated that reconstructions with either graft successfully restored anterior tibial translation. However, both anterior cruciate ligament reconstruction groups had significantly increased tibial rotation when compared with the controls, whereas no differences were found between the 2 reconstructed groups. Conclusion The 2 most frequently used autografts for anterior cruciate ligament reconstruction cannot restore tibial rotation to normal levels. Clinical Relevance New surgical techniques are needed that can better approximate the actual anatomy and function of the anterior cruciate ligament.

Effectiveness of Reconstruction of the Anterior Cruciate Ligament with Quadrupled Hamstrings and Bone-Patellar Tendon-Bone Autografts

Background The 2 most frequently used autografts for anterior cruciate ligament reconstruction are the bone-patellar tendon-bone and the quadrupled hamstrings tendon. Hypothesis Hamstring tendon graft is superior to patellar tendon graft in restoring tibial rotation during highly demanding activities because of its superiority in strength and linear stiffness and because it is closer morphologically to the anatomy of the natural anterior cruciate ligament. Study Design Case control study; Level of evidence, 3. Methods Eleven patients with patellar tendon graft anterior cruciate ligament reconstruction, 11 patients with hamstring tendon graft anterior cruciate ligament reconstruction, and 11 controls were assessed. Kinematic data were collected (50 Hz) with a 6-camera optoelectronic system while the subjects descended stairs and, immediately after, pivoted on their landing leg. The dependent variable examined was the tibial internal-external rotation during pivoting. All patients in both groups were also assessed clinically and with the use of a KT-1000 arthrometer to evaluate anterior tibial translation. Results The results demonstrated that reconstructions with either graft successfully restored anterior tibial translation. However, both anterior cruciate ligament reconstruction groups had significantly increased tibial rotation when compared with the controls, whereas no differences were found between the 2 reconstructed groups. Conclusion The 2 most frequently used autografts for anterior cruciate ligament reconstruction cannot restore tibial rotation to normal levels. Clinical Relevance New surgical techniques are needed that can better approximate the actual anatomy and function of the anterior cruciate ligament.

Biomechanical consequences of PCL deficiency in the knee under simulated muscle loads—an in vitro experimental study

The mechanism of chronic degeneration of the knee after posterior cruciate ligament (PCL) injury is still not clearly understood. While numerous biomechanical studies have been conducted to investigate the function of the PCL with regard to antero-posterior stability of the knee, little has been reported on its effect on the rotational stability of the knee. In this study, eight cadaveric human knee specimens were tested on a robotic testing system from full extension to 120° of flexion with the PCL intact and with the PCL resected. The antero-posterior tibial translation and the internal–external tibial rotation were measured when the knee was subjected to various simulated muscle loads. Under a quadriceps load (400 N) and a combined quadriceps/hamstring load (400/200 N), the tibia moved anteriorly at low flexion angles (below 60°). Resection of the PCL did not significantly alter anterior tibial translation. At high flexion angles (beyond 60°), the tibia moved posteriorly and rotated externally under the muscle loads. PCL deficiency significantly increased the posterior tibial translation and external tibial rotation. The results of this study indicate that PCL deficiency not only changed tibial translation, but also tibial rotation. Therefore, only evaluating the tibial translation in the antero-posterior direction may not completely describe the effect of PCL deficiency on knee joint function. Furthermore, the increased external tibial rotations were further hypothesized to cause elevated patello-femoral joint contact pressures. These data may help explain the biomechanical factors causing long-term degenerative changes of the knee after PCL injury. By fully understanding the etiology of these changes, it may be possible to develop an optimal surgical treatment for PCL injury that is aimed at minimizing the long-term arthritic changes in the knee joint.

Relative forefoot abduction and its relationship to foot length in vitro

Background. The human foot is often modelled as a rigid body in gait analysis. A more realistic model separates this segment into a forefoot and rearfoot. However, no three-dimensional data has been published on dynamic relative ab-adduction between these segments, and how this impacts changes in foot shape. Objective. The purpose was to quantify three-dimensionally forefoot ab-adduction relative to the rearfoot in vitro, and to determine how forefoot ab-adduction affects foot length. Methods. Video data were collected from reflective marker triads affixed to the ends of Steinmann pins drilled into the tibia, calcaneus, cuboid, and the first and fifth metatarsal bones. Medial and lateral foot length and forefoot ab-adduction relative to the rearfoot were calculated under two axial tibial loads (200 N, 600 N) and two input motions (dorsi-plantarflexion, internal external tibial rotation). Results. It was found that patterns of change for each variable were dependent on the degree of rigidity of the foot. Relative forefoot ab-adduction values ranged from 4.4 ° of adduction to 1.7 ° of abduction. Medial foot length values changed ± 0.8 mm (± 0.5%) and lateral foot length values changed ± 0.5 mm (± 0.3%). Medial foot length was correlated positively with relative forefoot abduction, and external tibial rotation was correlated positively with relative forefoot adduction.

The effects of removal and reconstruction of the anterior cruciate ligament on patellofemoral kinematics.

Patellofemoral pain may be associated with anterior cruciate ligament deficiency or may occur after anterior cruciate ligament reconstruction. We investigated the effects of the removal and reconstruction of the anterior cruciate ligament on the kinematics of the tibiofemoral and patellofemoral joints during physiologic levels of quadriceps muscle loads in seven cadaveric knees. A bone-patellar tendon-bone graft was used for intraarticular reconstruction of the anterior cruciate ligament. The spatial positions of the tibiofemoral and patellofemoral joints were measured between 0 degrees and 90 degrees of knee flexion in 15 degrees increments with a six degree-of-freedom digitizing system. Excision of the anterior cruciate ligament resulted in statistically significant increases in anterior tibial translation between 0 degrees and 90 degrees and valgus tibial rotation between 30 degrees and 90 degrees; intraarticular reconstruction returned these to levels not significantly different from those of the intact knee. Excision of the anterior cruciate ligament resulted in significant increases in lateral patellar tilt, ranging from 6.3 degrees to 9.0 degrees between full extension and 90 degrees of knee flexion, and in lateral patellar shift, ranging from 2.9 mm at 15 degrees of knee flexion to 5.9 mm at 90 degrees; intraarticular reconstruction returned these to levels not significantly different from those of the intact knee. Neither removal nor reconstruction of the anterior cruciate ligament significantly affected tibial internal-external rotation, patellar flexion, patellar mediolateral rotation, patellar anteroposterior translation, or patellar proximodistal translation.

Effect of combined axial compressive and anterior tibial loads on in situ forces in the anterior cruciate ligament: a porcine study.

This study investigated the impact of a combination of axial compressive and anterior-posterior tibial loads on the in situ forces in the anterior cruciate ligament. An axial compressive load is believed to contribute to increased stability of the knee joint; however, its effect on in situ forces in the anterior cruciate ligament has not been clearly defined, to our knowledge. It was hypothesized that the application of an axial compressive load, when combined with an anterior tibial load, would result in larger in situ forces in the anterior cruciate ligament than those caused by an isolated anterior tibial load. With use of a porcine knee model, the results confirmed this hypothesis; the addition of a 200 N axial compressive load to a 100 N anterior tibial load increased knee stability by reducing anterior-posterior tibial translation and internal-external tibial rotation and also caused a significant increase in in situ forces in the anterior cruciate ligament (p < 0.05). Specifically, there was a 34% increase in the in situ force at 30 degrees of flexion, a 68% increase at 60 degrees of flexion, and an 84% increase at 90 degrees of flexion compared with those for an isolated anterior tibial load of 100 N. Additionally, there was a statistically significant increase of the in situ forces in the anterior cruciate ligament at 60 and 90 degrees as compared with those at 30 degrees. These results suggest that axial compressive loads on the knee may play a role in injury of the anterior cruciate ligament when the knee is flexed.

Three-dimensional motion analysis of clinical stress tests for anterior knee subluxations.

The three rotations and three translations that comprise total knee motion were simultaneously measured in cadaveric knees during the commonly employed clinical tests for anterior cruciate injury. A second study determined the three-dimensional motions that occurred when known forces and moments were applied. A total of eight whole lower limbs were studied. A 6 degree-of-freedom instrumented linkage (3-D electrogoniometer), rigidly mounted to the tibia and femur, was used. The ligaments sectioned included the lateral extraarticular restraints (iliotibial band, lateral capsule) and the anterior cruciate ligament, both separately and in combination. After sectioning the anterior cruciate ligament alone, anterior displacement of both the medial and lateral tibial condyles increased markedly during the flexion rotation drawer and pivot shift tests. At 30 degrees knee flexion, total anterior-posterior displacement increased 100 percent, but internal-external tibial rotation increased only 15 percent. In all the anterior displacement type of clinical tests (including Lachman's test), there was not a true rigid coupling of knee motions because the examiner controlled the amount of internal tibial rotation and anterior tibial translation. After anterior cruciate sectioning alone, both the lateral and medial tibial condyles displaced anteriorly. Sectioning the medial structures caused additional anterior translation of the medial and lateral tibial condyles. We measured many different combinations of motions that depend on the ligament and capsular structures injured, the clinical test used, and how the clinician performed the test. Differing types of anterior subluxation require that the separate subluxations of the medial and lateral tibial condyles be determined during each stress test.