Anastasios D. Georgoulis

Three-dimensional tibiofemoral kinematics of the anterior cruciate ligament-deficient and reconstructed knee during walking.

Background It is possible that gait abnormalities may play a role in the pathogenesis of meniscal or chondral injury as well as osteoarthritis of the knee in patients with anterior cruciate ligament deficiency. Hypothesis The three-dimensional kinematics of anterior cruciate ligament-deficient knees are changed even during low-stress activities, such as walking, but can be restored by reconstruction. Study Design Case control study. Methods Using a three-dimensional optoelectronic gait analysis system, we examined 13 patients with anterior cruciate ligament-deficient knees, 21 patients with anterior cruciate ligament-reconstructed knees, and 10 control subjects with uninjured knees during walking. Results Normal patterns of knee flexion-extension, abduction-adduction, and internal-external rotation during the gait cycle were maintained by all subjects. A significant difference in tibial rotation angle during the initial swing phase was found in anterior cruciate ligament-deficient knees compared with reconstructed and control knees. The patients with anterior cruciate ligament-deficient knees rotated the tibia internally during the initial swing phase, whereas the others rotated externally. Conclusions Patients with anterior cruciate ligament-deficient knees experienced repeated episodes of rotational instability during walking, whereas patients with reconstruction experienced tibial rotation that is closer to normal. Clinical Relevance Repeated episodes of knee rotational instability may play a role in the development of pathologic knee conditions.

The effects of anterior cruciate ligament reconstruction on tibial rotation during pivoting after descending stairs.

Recent in vitro research suggests that ACL reconstruction does not restore tibial rotation. This study investigated rotational knee joint stability in vivo during a combined descending and pivoting movement that applies a high rotational load to the knee joint. We studied 20 ACL reconstructed patients (bone–patellar tendon–bone graft) and 15 matched controls with a six-camera optoelectronic system performing the examined movement. In the control group the results showed no significant differences in the amount of tibial rotation between the two sides. No significant differences were also found between the contralateral intact leg of the ACL group and the healthy control. However, a significant difference was found within the ACL reconstructed group and between the reconstructed and the contralateral intact leg. Therefore ACL reconstruction may not restore tibial rotation even though anterior tibial translation has been reestablished.

Tibial rotation is not restored after ACL reconstruction with a hamstring graft.

Recent research suggests ACL reconstruction does not restore tibial rotation to normal levels during high demand activities when a bone-patellar tendon-bone graft is used. We asked if an alternative graft, the semitendinosus-gracilis (ST/G) tendon graft, could restore tibial rotation during a high demand activity. Owing to its anatomic similarity with the normal ACL we hypothesized the ST/G graft could restore excessive tibial rotation to normal healthy levels along with a successful reinstatement of the clinical stability of the knee. We assessed tibial rotation in vivo, using gait analysis. We compared the knees of ACL reconstructed patients with an ST/G graft to their intact contralateral and healthy controls during a pivoting task that followed a stair descent. We also evaluated knee stability after ACL reconstruction with standard clinical tests. ACL reconstruction with the ST/G graft and with current techniques did not restore tibial rotation to previous physiological levels during an activity with increased rotational loading at the knee, although abnormal anteroposterior (AP) tibial translation was restored.

Tibial rotation in anterior cruciate ligament (ACL)-deficient and ACL-reconstructed knees: a theoretical proposition for the development of osteoarthritis.

Excessive tibial rotation has been documented in anterior cruciate ligament (ACL) deficiency during walking. ACL reconstruction has been unable to correct this abnormality in activities that are more demanding than walking and involve both anterior and rotational loading of the knee. These findings persist regardless of graft selection for the ACL reconstruction (bone-patellar tendon-bone or semitendinosus gracilis). Based on this research work, we propose a theoretical perspective for the development of osteoarthritis in both the ACL-deficient and the ACL-reconstructed knee. We propose that excessive tibial rotation will lead to abnormal loading of the cartilage areas that are not commonly loaded in the healthy knee. Over time, this abnormal loading will lead to osteoarthritis. We hypothesise that the development of new surgical procedures and grafts, such as a more horizontally oriented femoral tunnel or a double-bundle ACL reconstruction, could possibly restore tibial rotation to normal levels and prevent future knee pathology. However, in vivo gait analysis studies are needed to examine the effects of these surgical procedures on tibial rotation. Prospective in vivo and in vitro studies are also necessary to verify or refute our theoretical proposition for the development of osteoarthritis.

Effectiveness of reconstruction of the anterior cruciate ligament with quadrupled hamstrings and bone-patellar tendon-bone autografts : An in vivo study comparing tibial internal-external rotation

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.

A Novel Approach to Measure Variability in the Anterior Cruciate Ligament Deficient Knee During Walking: The Use of the Approximate Entropy in Orthopaedics

Objective. The evaluation of variability of biological rhythmic activities through measures such as Approximate Entropy (ApEn) has provided important information regarding pathology in disciplines such as cardiology and neurology. This research lead to the “loss of complexity hypothesis” where decreased variability is associated with loss of healthy flexibility rendering the system more rigid and unable to adapt to stresses. ApEn as a measure of variability and complexity, correlates well with pathology while, in some cases, it is predictive of subsequent clinical changes. The study of human gait could benefit from the application of ApEn since it is also a rhythmical oscillation. Our aim was to assess the variability of the ACL deficient knee, since ACL rupture is a common musculoskeletal injury and is accompanied by altered gait patterns and future pathology in the joint. We hypothesized that the ACL deficient knee will exhibit more regular and less variable walking patterns than the contralateral intact knee. Methods. Ten subjects with unilateral deficiency walked on a treadmill at their self-selected speed, 20% faster, and 20% slower, while kinematics were collected (50 Hz) from 80 consecutive strides for each condition. The ApEn of the resulted knee joint flexion-extension time series was calculated. Results. Significantly smaller ApEn values were found in the ACL deficient knee when compared with the contralateral intact (F = 5.57, p = 0.022), for all speeds. ApEn values significantly increased (F = 5.79, p = 0.005) with increases in walking speed. Conclusions. The altered properties of the ACL deficient knee, which exhibits more regular and less variable patterns than the contralateral intact knee, may decrease the adaptability of the system rendering it less able to adjust to perturbations. This could explain the increased future pathology found in the deficient knee. ApEn can be an important tool in assessing pathology and therapeutic interventions in orthopaedics.

Transtibial versus anteromedial portal of the femoral tunnel in ACL reconstruction: A cadaveric study

The aim of this cadaveric study was to compare the transtibial versus the anteromedial portal with respect to the anatomic femoral positioning of the ACL attachment. Ten fresh frozen cadaveric knees were included in our study. A standard arthroscopy was performed and the normal ACL was partially cut through with arthroscopic scissors leaving a small footprint of 2 mm at the anatomical insertion area on the lateral femoral condyle. The femoral tunnel was drilled through the tibial tunnel and subsequently through the anteromedial portal. Using a probe with standard magnification, we measured the distances of the two femoral tunnels from the margin of ACL footprint arthroscopically. The femurs were then dissected and we measured the distances of the two tunnels from the posterior part of the lateral femoral condyle. The median arthroscopically measured distance of the centers of transtibial femoral tunnel and of the femoral tunnel through the anteromedial portal from the margin of the femoral ACL footprint were 6.20 mm and 2.80 mm respectively. The difference was statistically significant. After femoral dissection the median distance of the centers of the transtibial femoral tunnel and the femoral tunnel performed through the anteromedial portal from the border of the articular surface at the lateral femoral condyle was 6.10 mm and 5.25 mm respectively (p<0.001). Both measurements showed that ACL reconstruction technique through the anteromedial portal is more accurate compared to the transtibial technique.

Follow-up evaluation 2 years after ACL reconstruction with bone-patellar tendon-bone graft shows that excessive tibial rotation persists.

ObjectiveTo investigate in vivo if the increased tibial rotation found in anterior cruciate ligament (ACL)-deficient patients before surgery is restored 2 years after the reconstruction, during 2 high-demanding activities. DesignProspective follow-up study. SettingA gait analysis laboratory. ParticipantsNine subjects with unilateral ACL rupture, reconstructed with a bone–patellar tendon–bone (BPTB) graft, and 10 healthy control subjects. InterventionsAll the ACL-deficient patients underwent a unilateral ACL reconstruction after prereconstruction data acquisition. Main Outcome MeasurementsUsing a 6-camera motion analysis system, kinematics were collected as subjects (1) descended from a stair and, after foot contact, pivoted on the landing leg at 90°; and (2) jumped from a platform, landed with both feet on the ground and, after foot contact, pivoted on the right or left leg at 90° in a similar fashion. The dependent variable examined was the maximum range of motion of tibial rotation during the pivoting period. ResultsFor both activities, no significant differences were found between the control healthy knee and the intact knee of the patient group before and 2 years after the ACL reconstruction. Significant differences were found between the control healthy knee and the affected knee of the patients group for both activities, both before and 2 years after the ACL reconstruction. ConclusionThe increased tibial rotation found in the ACL-deficient knees was not restored with reconstruction using a BPTB graft, even 2 years postoperatively. The authors propose that this excessive tibial rotation over time may lead to further deterioration of the knee resulting from abnormal loading at areas of the cartilage that are not commonly loaded in a healthy knee.

ACL deficiency affects stride-to-stride variability as measured using nonlinear methodology.

Previous studies suggested that the small fluctuations present in movement patterns from one stride to the next during walking can be useful in the investigation of various pathological conditions. Previous studies using nonlinear measures have resulted in the development of the “loss of complexity hypothesis” which states that disease can affect the variability and decrease the complexity of a system, rendering it less able to adjust to the ever changing environmental demands. The nonlinear measure of the Lyapunov Exponent (LyE) has already been used for the assessment of stride-to-stride variability in the anterior cruciate ligament (ACL) deficient knee in comparison to the contralateral intact knee. However, there is biomechanical evidence that after ACL rupture, adaptations are also present in the contralateral intact knee. Thus, our goal was to investigate stride-to-stride variability in the ACL deficient knee as compared to a healthy control knee. Seven subjects with unilateral ACL deficiency and seven healthy controls walked at their self-selected speed on a treadmill, while three-dimensional knee kinematics was collected for 80 consecutive strides. A nonlinear measure, the largest LyE was calculated from the resulted knee joint flexion-extension data of both groups. Larger LyE values signify increased variability and increased sensitivity to initial conditions. Our results showed that the ACL deficient group exhibited significantly less variable walking patterns than the healthy control. These changes are not desirable because they reflect decreases in system’s complexity, which indicates narrowed functional responsiveness, according to the “loss of complexity hypothesis.” This may be related with the increased future pathology found in ACL deficient patients. The methods used in the present paper showed great promise to assess the gait handicap in knee injured patients.

Nerve and vessel injuries during high tibial osteotomy combined with distal fibular osteotomy: a clinically relevant anatomic study.

Abstract Based on our clinical experience and an anatomical study, we examined the conditions under which injury to the popliteal artery, tibial nerve or peroneal nerve and its branches may occur during high tibial osteotomy. In 250 high tibial osteotomies performed in our department, we observed the following intraoperative complications. (1) The popliteal artery was severed in 1 patient and repaired by the same surgical team using a microsurgical technique. (2) A tibial nerve paresis also occurred in 1 patient. (3) In 3 patients, temporary palsy of the anterior tibialis muscle was documented. (4) In 4 other patients, palsy of the extensor hallucis longus occurred. To investigate the causes of these complications in the popliteal artery, tibial nerve and branches of the peroneal nerve, we dissected the neurovascular structures surrounding the area of the osteotomy in 10 cadaveric knees and performed a high tibial osteotomy in another 13 cadaveric knees. We concluded the following. (1) The popliteal artery and tibial nerve are protected, at the level of the osteotomy, behind the popliteus and tibialis posterior muscles. Damage can occur only by placing the Hohman retractor behind the muscles. The insertion of the muscles is very close to the periosteum and can be separated only with a scalpel. (2) The tibialis anterior muscle is innervated by a group of branches arising from the deep branch of the peroneal nerve. In two-thirds of the dissected knees, we found a main branch close to the periosteum, which can be damaged by dividing the muscle improperly or due to improper placement and pressure of the Hohman retractor. This may explain the partially reversible muscle palsy. (3) The extensor hallucis longus is also innervated by 2–3 thin branches, arising from the deep branch of the peroneal nerve, but in 25% of the specimens, only one large branch was found. This branch is placed under tension by manipulating the distal tibia forward. Thus, it may be damaged by the Hohman retractor during distal screw fixation, tensioned by hyperextension or directly injured during midshaft fibular osteotomy.