Three dimensional motion analysis of within and between day repeatability of tibial rotation during pivoting

Two-to-three times increase in natural hip and lumbar non-sagittal plane kinematics can lead to anterior cruciate ligament injury and cartilage failure scenarios during single-leg landings

BACKGROUND

Analyzing sports injuries is essential to mitigate risk for injury, but inherently challenging using in vivo approaches. Computational modeling is a powerful engineering tool used to access biomechanical information on tissue failure that cannot be obtained otherwise using traditional motion capture techniques.

METHODS

We extrapolated high-risk kinematics associated with ACL strain and cartilage load and stress from a previous motion analysis of 14 uninjured participants. Computational simulations were used to induce ACL failure strain and cartilage failure load, stress, and contact pressure in two age- and BMI-matched participants, one of each biological sex, during single-leg cross drop and single-leg drop tasks. The high-risk kinematics were exaggerated in 20% intervals, within their physiological range of motion, to determine if injury occurred in the models. Where injury occurred, we reported the kinematic profiles that led to tissue failure.

FINDINGS

Our findings revealed ACL strains up to 9.99%, consistent with reported failure values in existing literature. Cartilage failure was observed in all eight analyzed conditions when increasing each high-risk kinematic parameter by 2.61 ± 0.67 times the participants' natural landing values. The kinematics associated with tissue failure included peak hip internal rotation of 22.48 ± 19.04°, peak hip abduction of 22.51 ± 9.09°, and peak lumbar rotation away from the stance limb of 11.56 ± 9.78°.

INTERPRETATION

Our results support the ability of previously reported high-risk kinematics in the literature to induce injury and add to the literature by reporting extreme motion limits leading to injurious cases. Therefore, training programs able to modify these motions during single-leg landings may reduce the risk of ACL injury and cartilage trauma.

Development of new cartilage lesions after ACL reconstruction is associated with abnormal knee rotation

PURPOSE

The purpose of this study is to examine the association between the development of articular cartilage pathology and knee rotation after single-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

Seventeen patients that underwent single-bundle ACL reconstruction and did not have any cartilage lesions at the time of surgery based on the Outerbridge classification or meniscal injury that required meniscectomy > 20% were examined by MRI and in the biomechanics laboratory at a 6-year minimum follow-up. Cartilage lesions that occurred after reconstruction were graded on MRI according to a modified Noyes scale. For cartilage evaluation, the lateral and medial femoral condyles were divided into 9 segments each (lateral, central, and medial third and each third was divided into anterior, central, and posterior segment). Tibial rotation during a pivoting task was measured with optoelectronic motion analysis system and side-to-side differences of tibial rotation between the reconstructed and contralateral intact knees were calculated. The association between the total modified Noyes scale score (outcome variable) and side-to-side differences of tibial rotation after controlling for meniscectomy and meniscal repair was investigated with hierarchical regression models.

RESULTS

Side-to-side difference of tibial rotation was associated with total modified Noyes scale score (p = 0.015, β = 0.667, adjusted R² = 42.1%). All patients developed new cartilage lesions in MRI located mainly at the central region of the lateral femoral condyle and less frequently in the central and anterior regions of the medial femoral condyle.

CONCLUSION

Abnormally increased tibial rotation that persists after ACL-R is significantly associated with the development of new articular cartilage lesions at mean 8.4 years after reconstruction which were located mainly at the central region of the LFC and secondarily in the central and anterior regions of the MFC (more superficial lesions). These findings suggest that there is emerging evidence that abnormal rotational kinematics is a potential risk factor for the pathogenesis and onset of posttraumatic articular cartilage degeneration after ACLR.

LEVEL OF EVIDENCE

IV.

Restoring tibiofemoral alignment during ACL reconstruction results in better knee biomechanics

PURPOSE

Anterior cruciate ligament (ACL) reconstruction (ACLR) aims to restore normal knee joint function, stability and biomechanics and in the long term avoid joint degeneration. The purpose of this study is to present the anatomic single bundle (SB) ACLR that emphasizes intraoperative correction of tibiofemoral subluxation that occurs after ACL injury. It was hypothesized that this technique leads to optimal outcomes and better restoration of pathological tibiofemoral joint movement that results from ACL deficiency (ACLD).

METHODS

Thirteen men with unilateral ACLD were prospectively evaluated before and at a mean follow-up of 14.9 (SD = 1.8) months after anatomic SB ACLR with bone patellar tendon bone autograft. The anatomic ACLR replicated the native ACL attachment site anatomy and graft orientation. Emphasis was placed on intraoperative correction of tibiofemoral subluxation by reducing anterior tibial translation (ATT) and internal tibial rotation. Function was measured with IKDC, Lysholm and the Tegner activity scale, ATT was measured with the KT-1000 arthrometer and tibial rotation (TR) kinematics were measured with 3Dmotion analysis during a high-demand pivoting task.

RESULTS

The results showed significantly higher TR of the ACL-deficient knee when compared to the intact knee prior to surgery (12.2° ± 3.7° and 10.7° ± 2.6° respectively, P = 0.014). Postoperatively, the ACLR knee showed significantly lower TR as compared to the ACL-deficient knee (9.6°±3.1°, P = 0.001) but no difference as compared to the control knee (n.s.). All functional scores were significantly improved and ATT was restored within normal values (P < 0.001).

CONCLUSIONS

Intraoperative correction of tibiofemoral subluxation that results after ACL injury is an important step during anatomic SB ACLR. The intraoperative correction of tibiofemoral subluxation along with the replication of native ACL anatomy results in restoration of rotational kinematics of ACLD patients to normal levels that are comparable to the control knee. These results indicate that the reestablishment of tibiofemoral alignment during ACLR may be an important step that facilitates normal knee kinematics postoperatively.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

Three-dimensional kinematic and kinetic analysis of knee rotational stability in ACL-deficient patients during walking, running and pivoting

Background

Anterior cruciate ligament (ACL) deficiency leads to altered stability of the knee. The purpose of this study was to compare the dynamic, rotational stability of the knee, expressed as rotational stiffness, between anterior cruciate ligament-deficient (ACLD) knees, their contralateral intact knees (ACLI) and a knee healthy control group during walking, running and 90° pivoting. We hypothesized a larger tibial internal rotation, a smaller knee joint external moment and a lower rotational stiffness in the ACLD group compared to the ACLI and the control group.

Methods

Kinematic and kinetic data were collected from both legs of 44 ACLD patients and 16 healthy controls during walking, running and a pivoting maneuver (descending a staircase and immediately pivoting 90° on the landing leg). Motion data were captured using 8 high-speed cameras and a force-plate. Reflective markers were attached to bony landmarks of the lower limb and rigid clusters on the shank and thigh (CASH model). Maximum internal tibial rotation and the corresponding rotational moment were identified for all tasks and groups and used to calculate rotational stiffness (= Δmoment /Δrotation) of the knee.

Results

The tibial internal rotation of the ACLD knee was not significantly different from the ACLI knee during all three tasks. During walking and running, the tibial rotation of the control group was significantly different from both legs of the ACL-injured patient. For pivoting, no difference in tibial rotation between knees of the ACLD, ACLI and the control group was found. Knee joint external moments were not significantly different between the three groups during walking and pivoting. During running, the moments of the ACLI group were significantly higher than both the knees of the ACLD and the control group. Rotational stiffness did not differ significantly between groups in any of the three tasks.

Conclusion

A high-intensity activity combining stair descent and pivoting produces similar angular rotations, knee joint external moments and rotational stiffness in ACLD knees compared to ACLI knees and the control group. During running, the ACLI knee displayed a higher external moment than the ACLD and the healthy control group. This could indicate some type of protective strategy or muscular adaptation in the ACL-injured patients.

Foot posture and function have only minor effects on knee function during barefoot walking in healthy individuals

BACKGROUND

Foot posture has been postulated as a risk factor for overuse injuries of the knee, however the link between foot posture and knee joint function is unclear. The aims of this study were to: (i) compare knee adduction moment and knee joint rotations between normal, planus and cavus foot posture groups, and (ii) to determine the relationship between rearfoot and midfoot joint rotations and knee adduction moment magnitude.

METHODS

Rotation of the knee, rearfoot and midfoot was evaluated in 97 healthy adults that were classified as normal (n=37), cavus (n=30) or planus (n=30) for the Foot Posture Index, Arch Index and normalised navicular height. One way analyses of variance were used to compare tri-planar knee joint rotation, knee adduction moment peak variables and knee adduction angular impulse between foot posture groups. Pearson's correlation coefficient was used to investigate the association between rearfoot and midfoot joint rotation during initial contact phase and the magnitude of 1st knee adduction moment peak.

FINDINGS

The planus group displayed significantly greater external rotation angle at heel contact compared to both normal and cavus groups. The planus groups also displayed greater extension at heel contact and sagittal plane flexion range of motion during propulsion and early swing compared to the cavus group. Otherwise, differences between groups were characterised by small effect sizes. There was no association between rearfoot or midfoot joint rotations and knee adduction moment.

INTERPRETATION

These findings suggest that in healthy individuals, foot posture and foot joint rotations do not substantially influence knee joint rotations and knee adduction moment while walking at a comfortable pace.

The PCL index is correlated with the control of rotational kinematics that is achieved after anatomic anterior cruciate ligament reconstruction

BACKGROUND

The posterior cruciate ligament (PCL) index quantifies the curvature of the PCL seen on magnetic resonance imaging (MRI) that is caused by a change in tibiofemoral alignment in the anterior cruciate ligament (ACL)-deficient knee. It has been proposed that the PCL index may be useful in assessing the success of ACL reconstruction (ACLR). Hypothesis/

PURPOSE

The purpose of this study was to test if the PCL index is predictive of in vivo rotational kinematics and joint laxity measures in knees of patients after single-bundle ACLR. The hypothesis was that the PCL index is predictive of rotational knee kinematics and objective laxity scores.

STUDY DESIGN

Controlled laboratory study.

METHODS

At a mean of 18.1 months postoperatively, the PCL index was defined on MRI in 16 patients prospectively followed up after anatomic single-bundle ACLR and in 16 matched controls. The patients were evaluated with 3-dimensional motion analysis during (1) descending and pivoting as well as (2) landing and pivoting tasks. The side-to-side difference in tibial rotation range of motion between the reconstructed knee and the contralateral intact knee was calculated. The side-to-side difference in anterior tibial translation was measured with a KT-1000 arthrometer. Linear regression models were used with the PCL index as a predictor of the side-to-side difference in tibial rotation for each task and the side-to-side difference in anterior tibial translation.

RESULTS

The PCL index of the reconstructed knees was significantly lower compared with that of the control knees (P < .001). The index was predictive of the side-to-side difference in tibial rotation during both tasks (R (2) = 0.472 and 0.477, P = .003), with a lower index being indicative of increased rotational laxity. It was not predictive of anterior tibial translation (at 134 N: R (2) = 0.13, P = .17; at maximum force: R (2) = 0.009, P = .726).

CONCLUSION

The PCL index after anatomic single-bundle ACLR using a bone-patellar tendon-bone graft is predictive of rotational kinematics during in vivo dynamic pivoting activities. The results show that the PCL index is correlated with the postoperative ability to control rotational kinematics of the knee joint.

CLINICAL RELEVANCE

This study provides evidence regarding the interplay between restoration of the native ACL's anatomy and the PCL's appearance and suggests that the effective restoration of tibiofemoral alignment after ACLR that is reflected in the PCL index translates into better functional outcomes as measured by tibial rotation during pivoting activities.

Effects of knee bracing on tibial rotation during high loading activities in anterior cruciate ligament-reconstructed knees

PURPOSE

To test whether knee bracing restores normal rotational knee kinematics in anterior cruciate ligament (ACL)-reconstructed knees during high-demand, athletic activities.

METHODS

Twenty male patients who had undergone unilateral ACL reconstruction with a bone-patellar tendon-bone autograft were assessed in vivo. The mean time from surgery to data collection was 26 months (range, 25 to 28 months). An 8-camera optoelectronic system was used to collect kinematic data while each patient performed 2 demanding tasks: (1) immediate pivoting after descending from a stair and (2) immediate pivoting after landing from a platform. Each task was performed under 3 conditions for the reconstructed knee: (1) wearing a prophylactic brace (braced condition), (2) wearing a patellofemoral brace (sleeved condition), and (3) without a brace (non-braced condition). As a control group, patients with intact ACLs were tested without any bracing. This study protocol was identical to the protocol of a previous study that investigated the effect of bracing on ACL-deficient athletes.

RESULTS

For both tasks, the range of motion of tibial rotation was significantly lower in the intact knee compared with all 3 conditions of the ACL-reconstructed knee (P ≤ .014). Placing a brace or a sleeve on the ACL-reconstructed knee resulted in lower rotation than the non-braced condition (P ≤ .022), whereas no significant differences were found between the sleeved and the braced conditions (P ≥ .110).

CONCLUSIONS

Bracing limited the excessive tibial rotation in ACL-reconstructed knees during pivoting that occurs under high-demand activities. However, full restoration to normative values was not achieved. Thereby, braces have the potential to decrease rotational knee instability that still remains after ACL reconstruction.

The effect of anterior cruciate ligament graft orientation on rotational knee kinematics

PURPOSE

To determine whether coronal graft orientation and tunnel placement for single-bundle anterior cruciate ligament (ACL) reconstruction is associated with tibial rotation excursion during functional activities.

METHODS

Eighty-four patients who had undergone ACL reconstruction over a ten-year time span had tibial rotation measured during level walking, using a three-dimensional motion analysis system. Fifty-two patients also had measures taken during the more dynamic task of single-limb landing. During the 10-year period, the position of the graft was deliberately changed from a vertical to more horizontal orientation in the coronal plane. Post-operative radiographs were analysed for the coronal graft orientation and femoral and tibial tunnel positions. Radiographic measurements of graft orientation and tunnel position were then correlated with the amount of tibial rotational excursion recorded during the walking and landing tasks.

RESULTS

For the single-limb landing task, a significant positive correlation was observed between the coronal graft angle and rotational excursion (R = 0.35, R (2)  = 0.12, p = 0.01). This indicated greater rotational excursion was associated with vertical graft orientation, but only explained 12 % of the variance. No correlations were found between coronal graft angle and tibial rotation during level walking.

CONCLUSIONS

These findings support the notion that ACL graft orientation may play a role in rotational kinematics of the ACL-reconstructed knee, particularly during higher impact activities.

LEVEL OF EVIDENCE

IV.

The effect of knee braces on tibial rotation in anterior cruciate ligament-deficient knees during high-demand athletic activities

OBJECTIVE

To examine if bracing can restrict tibial rotation in anterior cruciate ligament (ACL)-deficient patients during high loading activities.

DESIGN

Repeated measures. Kinematic data were collected with an 8-camera Vicon system while each patient performed 2 tasks that are known to cause increased rotational and translational loads on the knee: (1) descending from a stair and subsequent pivoting, and (2) landing from a platform and subsequent pivoting. The tasks were repeated under 3 brace conditions for the ACL-deficient knee: (1) wearing a prophylactic brace (braced condition), (2) wearing a patellofemoral brace (sleeved condition), and (3) without brace (unbraced condition).

SETTING

Biomechanical laboratory study.

PATIENTS

Twenty-one male subjects with a confirmed unilateral ACL rupture were assessed in vivo.

MAIN OUTCOME MEASURES

Tibial internal rotation. Two repeated measures ANOVAs tested for differences in tibial internal rotation among the 3 conditions of the ACL-deficient knee and the unbraced condition of the intact knee.

RESULTS

In both tasks, tibial rotation was significantly lower in the intact knee compared with all 3 conditions of the ACL-deficient knee (P ≤ 0.031). Bracing the ACL-deficient knee resulted in lower rotation than the unbraced (P ≤ 0.001) and sleeved (P ≤ 0.033) conditions. The sleeved condition resulted in lower tibial rotation in the drop landing and pivoting task compared with the unbraced condition (P = 0.019) but not in the stair descending and pivoting task (P = 0.256).

CONCLUSIONS

Bracing decreased the excessive tibial rotation in ACL-deficient patients during high-demand activities but failed to fully restore normative values. If knee braces can enhance rotational knee stability in ACL-deficient patients, then they could possibly play an important role in preventing further knee pathology in such patients.

Hamstring tendon anterior cruciate ligament reconstruction: does gracilis tendon harvest matter?

PURPOSE

Hamstring tendon grafts are a popular choice for anterior cruciate ligament (ACL) reconstruction. Typical morbidity reported after hamstring tendon harvest is muscle weakness in flexion, and whilst still a matter for debate, this morbidity may be greater if the gracilis tendon is harvested in addition to the semitendinosus. This study sought to comprehensively compare the outcome of ACL reconstructions in which the semitendinosus was harvested alone (ST group) or with the gracilis (ST/G group).

METHODS

Twenty patients (ten ST, ten ST/G) were assessed with a variety of measures that included subjective scores, function, strength and tibial rotation as measured by gait analysis during a pivoting task.

RESULTS

Results showed that the graft diameter was significantly larger in the ST group, but there were no other differences between the groups for any other outcome measure.

CONCLUSION

Harvesting the gracilis in addition to semitendinosus does not appear to affect either the outcome or graft-related morbidity after hamstring ACL reconstruction.

Tibial rotation during pivoting in anterior cruciate ligament reconstructed knees using a single bundle technique

BACKGROUND

Anterior cruciate ligament reconstruction does not necessarily restore normal knee movement. Increased tibial rotation has previously been noted during pivoting activities and may be due to the orientation of the anterior cruciate ligament graft associated with traditional single bundle reconstruction techniques. Recent research has shown that it is possible to limit rotation during level walking using a single bundle anterior cruciate ligament reconstruction. This study evaluated rotational knee kinematics during a pivot task in a group of patients who had undergone anterior cruciate ligament reconstruction using a single bundle technique and compared the findings to a normal control group.

METHODS

In 27 anterior cruciate ligament reconstruction and 25 control participants, internal-external rotation was measured during a descend stairs and pivot task in a gait laboratory.

FINDINGS

Results showed that the anterior cruciate ligament reconstruction patients had less internal tibial rotation (for both range of rotation and maximum rotation) than the control participants (effect size=0.7).

INTERPRETATION

These results suggest that it is possible to limit rotation after anterior cruciate ligament reconstruction using a single bundle technique, even during a pivoting movement that places a high rotational load at the knee joint. The positioning of the femoral tunnel in a more anatomical position may be responsible for the reduced tibial rotation.

Tibial rotation in anterior cruciate ligament reconstructed knees during single limb hop and drop landings

BACKGROUND

Alterations in knee joint kinematics have been suggested as a potential mechanism that influences the development of osteoarthritis of the knee after anterior cruciate ligament reconstruction. Whilst previous work has shown changes in internal-external tibial rotation during level walking, many patients aim to return to high impact activities following surgery. This study examined tibial rotation during single limb hop and drop landings in anterior cruciate ligament reconstructed knees compared to a control group, and also evaluated the influence of graft type (hamstring or patellar tendon).

METHODS

In 48 participants (17 patellar tendon graft, 18 hamstring graft and 13 controls) internal-external rotation was measured during single limb hop and drop landings in a gait laboratory at mean of 10 months after surgery.

FINDINGS

There was no difference between the two graft types and both patient groups had less internal rotation when compared to the control group. For 60% of patients, internal rotation values were at least 5° less than the control group mean.

INTERPRETATION

Anterior cruciate ligament reconstructed knees with both hamstring tendon and patellar tendon grafts show altered rotational kinematic patterns during high impact dynamic load activities.

Kinematic predictors of subjective outcome after anterior cruciate ligament reconstruction: an in vivo motion analysis study

PURPOSE

The purpose of this study was to test whether rotational knee kinematics during dynamic pivoting activities are predictive of subjective functional outcome (IKDC, Lysholm), objective laxity scores (KT max), and activity levels (Tegner) in patients after anterior cruciate ligament reconstruction (ACLR).

METHODS

Thirty-one patients with single-bundle ACLR were evaluated prospectively with 3D-motion analysis during (1) descending a stairway and pivoting and (2) landing from a jump and pivoting. The side-to-side difference of tibial rotation range of motion (SSDTR) between the ACLR and the contralateral intact knee was calculated for the pivoting phase of each task. Linear regression models were applied with SSDTR, for each task predictors of the subjective IKDC score, Lysholm score, anterior tibial translation, and Tegner activity level.

RESULTS

SSDTR for descending and landing were predictive of the IKDC subjective score (R(2) = 0.46, p < 0.001 and R(2) = 0.40, p < 0.001, respectively) with "medium" effect sizes and of the Lysholm score (R(2) = 0.13, p < 0.05 and R(2) = 0.09, n.s.) with "small" to "none" effect sizes. SSDTR was not predictive of anterior translation or Tegner activity level (n.s.).

CONCLUSIONS

Restoring rotational kinematics during dynamic pivoting activities after ACLR is predictive of functional outcome. The ability of the athlete after ACLR to control tibial rotation during pivoting activities may be predictive of functional outcome.

LEVEL OF EVIDENCE

Case series study. Level IV.

Tibial rotation in single- and double-bundle ACL reconstruction: a kinematic 3-D in vivo analysis

PURPOSE

The effect of double-bundle ACL reconstruction on knee kinematics has recently been studied by several authors under controlled laboratory conditions however little evidence has been derived from dynamic in vivo evaluations. This study hypothesized that tibial rotation during pivoting motor tasks would be better restored after double-bundle ACL reconstructions when compared with single-bundle procedures.

METHODS

Twenty patients with a chronic ACL rupture were randomly assigned to receive a single- or double-bundle ACL reconstruction. Both knees were evaluated pre-operatively by kinematic 3-D gait analysis while performing low- and high-demand motor tasks, including pivoting. At 6 months post-operatively, measurements were repeated in 16 patients. Ten healthy, sex- and age-matched subjects with no history of lower limb pathology formed the control group. The tibial rotational excursion was set as the dependent variable.

RESULTS

The results indicate that at 6 months after surgery both "anatomic" single- and double-bundle ACL reconstruction are able to restore tibial rotational excursion when compared with the contralateral knees and with control knees from uninjured subjects. Chronic ACL-deficient patients show an increase in tibial rotation in both knees during high-demand pivoting tasks.

CONCLUSIONS

Both "anatomic" single- and double-bundle ACL reconstruction adequately restore tibial rotational excursion in a human, "in vivo" kinematic model. As knee stability measurements by in vivo kinematic 3-D analysis more accurately represent actual knee loading during activities, the results of this study might better correlate with functional outcome after ACL reconstructions compared with static knee stability tests or ex vivo laboratory experiments. In such, the results of this dynamic study do not support the theoretical advantage of a double-bundle ACL reconstruction over an "anatomic" single-bundle ACL reconstruction.

Knee rotational stability during pivoting movement is restored after anatomic double-bundle anterior cruciate ligament reconstruction

BACKGROUND

The restoration of knee rotational stability after anatomic double-bundle anterior cruciate ligament (ACL) reconstruction has been demonstrated in the cadaveric model and with passive stress tests on humans but not yet with dynamic functional biomechanical tests performed by human participants.

PURPOSE

To prospectively investigate the range of tibial rotation of ACL-deficient and ACL-reconstructed knees during a pivoting task. The authors hypothesized that there would be a significant increase in tibial internal rotation in the ACL-deficient knee compared with the contralateral knee and that the increased rotation would return to normal after anatomic double-bundle ACL reconstruction.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Ten men with unilateral ACL injury performed a high-demand jump-landing and pivoting task before and after ACL reconstruction with mean follow-up of 11 months. The range of tibial rotation of the injured, reconstructed, and intact knees during the pivoting movement was measured by an optical motion analysis system. Paired t tests were performed to investigate any significant difference between the 2 limbs preoperatively and postoperatively and within the injured limb before and after the surgical treatment. Statistical significance was set at P < .05.

RESULTS

The range of tibial rotation was higher in the ACL-deficient knee (12.6° ± 4.5°) than in the intact knee (7.9° ± 3.1°) preoperatively (P < .05). The increased rotation was reduced in the reconstructed knee (8.9° ± 3.0°) after ACL reconstruction versus the intact knee postoperatively (8.2° ± 2.6°) (P < .05). There was no significant difference in the tibial rotation between the intact knee and the reconstructed knee postoperatively (P > .05).

CONCLUSION

As assessed with a dynamic functional pivoting movement, the anatomic double-bundle ACL reconstruction successfully restores knee rotational stability from an impaired level.

Alterations in joint kinematics during walking following hamstring and patellar tendon anterior cruciate ligament reconstruction surgery

BACKGROUND

Previous research has shown that patients with anterior cruciate ligament reconstruction have altered movement patterns in the reconstructed knee during walking. In the sagittal plane, graft specific changes in knee joint motion have been reported between hamstring and patellar tendon anterior cruciate ligament reconstruction grafts. This study examined the secondary planes of movement during walking in anterior cruciate ligament reconstructed knees to evaluate the influences of graft type (hamstring or patellar tendon) and control condition (control group or contralateral knee).

METHODS

In 54 participants (18 patellar tendon graft, 18 hamstring graft and 18 controls) varus-valgus and internal-external rotation was measured during level walking in a gait laboratory at mean of 10 months after surgery. All patients had undergone primary unilateral anterior cruciate ligament reconstruction within 12 months of injury.

FINDINGS

For internal-external rotation there was no difference between the graft types and both patient groups had reduced internal rotation (an external rotation offset) and reduced internal rotation range when compared to the control group and contralateral knee. For 31 of 36 patients, internal rotation values were less than the control group mean. The hamstring group had reduced varus rotation compared to both the patellar tendon and control groups, but not when compared to the contralateral knee.

INTERPRETATION

The results show that there are differences in tibial rotation during walking in anterior cruciate ligament reconstructed knees compared to both the contralateral knee and uninjured control group. These kinematic alterations may relate to the high incidence of knee osteoarthritis observed in this population over time. Reduced varus in the hamstring group may relate to the graft harvest.