Sagittal Knee Motion Research Articles

Lateral Extra-articular Tenodesis Contributes Little to Change In Vivo Kinematics After Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial

Background: Lateral extra-articular tenodesis (LET) in combination with anterior cruciate ligament (ACL) reconstruction (ACLR) has been proposed to improve residual rotatory knee instability in patients having ACL deficiency. Purpose/Hypothesis: The purpose was to compare the effects of isolated ACLR (iACLR) versus LET in combination with ACLR (ACLR+LET) on in vivo kinematics during downhill running. It was hypothesized that ACLR+LET would reduce the internal rotation of the reconstructed knee in comparison with iACLR. Study Design: Controlled laboratory study. Methods: A total of 18 patients with ACL deficiency were included. All participants were randomly assigned to receive ACLR+ LET or iACLR during surgery. Six months and 12 months after surgery, knee joint motion during downhill running was measured using dynamic biplane radiography and a validated registration process that matched patient-specific 3-dimensional bone models to synchronized biplane radiographs. Anterior tibial translation (ATT; positive value means “anterior translation”) and tibial rotation (TR) relative to the femur were calculated for both knees. The side-to-side differences (SSDs) in kinematics were also calculated (operated knee–contralateral healthy knee). The SSD value was compared between ACLR+LET and iACLR groups using a Mann-Whitney U test. Results: At 6 months after surgery, the SSD of ATT in patients who had undergone ACLR+LET (–1.9 ± 2.0 mm) was significantly greater than that in patients who had undergone iACLR (0.9 ± 2.3 mm) at 0% of the gait cycle (foot strike) (P = .031). There was no difference in ATT 12 months after surgery. Regarding TR, there were no differences between ACLR+LET and iACLR at either 6 months (P value range, .161-.605) or 12 months (P value range, .083-.279) after surgery. Conclusion: LET in combination with ACLR significantly reduced ATT at the instant of foot strike during downhill running at 6 months after surgery. However, this effect was not significant at 12 months after surgery. The addition of LET to ACLR had no effect on TR at both 6 and 12 months after surgery. Clinical Relevance: LET in combination with ACLR may stabilize sagittal knee motion during downhill running in the early postoperation phase, but according to this study, it has no effect on 12-month in vivo kinematics. Registration: NCT02913404 (ClinicalTrials.gov identifier)

Integrating a Potentiometer into a Knee Brace Shows High Potential for Continuous Knee Motion Monitoring.

Continuous monitoring of knee motion can provide deep insights into patients’ rehabilitation status after knee injury and help to better identify their individual therapeutic needs. Potentiometers have been identified as one possible sensor type for continuous monitoring of knee motion. However, to verify their use in monitoring real-life environments, further research is needed. We aimed to validate a potentiometer-embedded knee brace to measure sagittal knee kinematics during various daily activities, as well as to assess its potential to continuously monitor knee motion. To this end, the sagittal knee motion of 32 healthy subjects was recorded simultaneously by an instrumented knee brace and an optoelectronic reference system during activities of daily living to assess the agreement between these two measurement systems. To evaluate the potentiometer’s behavior during continuous monitoring, knee motion was continuously recorded in a subgroup (n = 9) who wore the knee brace over the course of a day. Our results show a strong agreement between the instrumented knee brace and reference system across all investigated activities as well as stable sensor behavior during continuous tracking. The presented potentiometer-based sensor system demonstrates strong potential as a device for measuring sagittal knee motion during daily activities as well as for continuous knee motion monitoring.

Effects of prolonged load carriage on angular jerk of frontal and sagittal knee motion

BackgroundDuring training, service members routinely walk with heavy body borne loads for long periods of time. These loads alter knee biomechanics and may produce jerky knee motions that reportedly increase joint loading and risk of musculoskeletal injury. Yet, it is unknown if service members use jerky knee motions during prolong walking with body borne load. Research questionTo quantify the effects of body borne load and duration of walking on the jerkiness of sagittal and frontal plane knee motion. MethodsEighteen participants had angular jerk of knee motion quantified while they walked (1.3 m/s) for 60-min with three body borne loads (0, 15, and 30 kg). Peak and cost of angular jerk for sagittal and frontal plane knee motion was quantified and submitted to a repeated measures linear model to test the main effects and interaction of load (0, 15, and 30 kg) and time (0, 15, 30, 45, and 60 min). ResultsBody borne load increased peak and cost of angular jerk for sagittal plane knee motion up to 35 % and 110 %, respectively, and frontal plane knee motion up to 20 % and 51 %, respectively (all p<0.001), while jerk cost of frontal plane knee motion (p=0.001) increased 31 % after walking 45 min. SignificanceBody borne load produced large (between 20 % and 110 %), incremental increases in angular jerk for both sagittal and frontal plane knee motion; whereas, duration of walking led to a 31 % increase in jerkiness of frontal plane knee motion. Service members who often walking for long periods of time with heavy body borne loads may have greater risk of developing musculoskeletal injury and disease due to large increases in jerky knee motions.

Knee motion and muscle activation patterns are altered in hip osteoarthritis: The effect of severity on walking mechanics

BackgroundKnee function is impaired in individuals with moderate hip osteoarthritis. How this extends to those undergoing total hip arthroplasty is unknown despite the common requirement for knee arthroplasty in this population. The study purpose was to determine whether sagittal plane knee joint movements and quadriceps and hamstring activation patterns differ between individuals with either moderate or severe unilateral hip osteoarthritis, and between ipsilateral and contralateral knees. Methods20 individuals with moderate osteoarthritis and 20 with severe osteoarthritis were recruited. Sagittal knee motion and surface electromyograms from the hamstrings and quadriceps were collected during treadmill walking at a self-selected speed. Principal component analysis captured amplitude and temporal sagittal plane motion and EMG waveform features. Student's t-tests and Analysis of Variance determined between group differences and within/between group leg differences. FindingsThe severe groups' contralateral knee was in greater flexion at initial contact and demonstrated a movement profile of a longer stance phase (p < 0.001). The severe group had reduced sagittal plane knee motion (p < 0.0001); more so in the ipsilateral knee (p < 0.0001). The severe group had greater hamstring (p = 0.009) and quadriceps activation (p < 0.001) overall, specifically mid-stance quadriceps bilaterally (p = 0.002). Ipsilateral sagittal plane knee motion was reduced in both groups. Compared with those with moderate osteoarthritis, individuals with severe osteoarthritis walk with reduced sagittal plane knee motion bilaterally, suggesting prolonged contralateral stance, and elevated mid-stance hamstring and quadriceps activation. InterpretationAltered kinematics and muscle activity could contribute to a greater mechanical demand on the contralateral knee in those with more severe hip osteoarthritis.

Differences in Medial and Lateral Posterior Tibial Slope: An Osteological Review of 1090 Tibiae Comparing Age, Sex, and Race

Background: Injuries to the anterior cruciate ligament (ACL) are common, and a number of knee morphological variables have been identified as risk factors for an ACL injury, including the posterior tibial slope (TS). However, limited data exist regarding innate population differences in the TS. Purpose: To (1) establish normative values for the medial and lateral posterior TS; (2) determine what differences exist between ages, sexes, and races; and (3) determine how internal or external tibial rotation (as occurs during sagittal knee motion) influences the stereotactic perception of the TS. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 545 cadaveric specimens (1090 tibiae) were obtained from the Hamann-Todd osteological collection. Specimens were leveled in the coronal, sagittal, and axial planes using a digital laser. Virtual representations of each bone were created with a 3-dimensional digitizer apparatus. The TS of the medial and lateral tibial plateaus were measured using techniques adapted from previous radiographic protocols. Medial and lateral TS were then again measured on 200 tibiae that were internally and externally rotated by 10° (axially). Results: The mean (±SD) medial TS was 6.9° ± 3.7° posterior, which was greater than the mean lateral TS of 4.7° ± 3.6° posterior (P < .001). Neither the medial nor lateral TS changed with age. Women had a greater mean TS compared with men on both the medial (7.5° ± 3.8° vs 6.8° ± 3.7°, respectively; P = .03) and lateral (5.2° ± 3.5° vs 4.6° ± 3.5°, respectively; P = .04) sides. Black specimens had a greater mean medial TS (8.7° ± 3.6° vs 5.8° ± 3.3°, respectively; P < .001) and lateral TS (5.9° ± 3.3° vs 3.8° ± 3.5°, respectively; P < .001) compared with white specimens. Axial rotation was shown to increase the perception of the medial and lateral TS (P < .001). Conclusion: The medial TS was shown to be greater than the lateral TS. Important sex- and race-based differences exist in the TS. This study also highlights the role of axial rotation in measuring the TS.

Unilateral ankle immobilization alters the kinematics and kinetics of lifting

Theoretical and empirical data support the notion that distal lower extremity joint dysfunction could influence the low-back injury potential of workers, but the impact of unilateral ankle immobilization on low-back loading during lifting has yet to be examined. To examine the influence of unilateral ankle immobilization on the kinematics and kinetics of lifting. With and without their right ankle immobilized, 10 men performed laboratory-simulated occupational lifting tasks. Together with force platform data, three-dimensional kinematics of the lumbar spine, pelvis, and lower extremities were collected, and a dynamic biomechanical model was used to calculate peak compressive and shear loads imposed on the L4/L5 intervertebral joint. In comparison to the unaffected conditions, ankle immobilization generally resulted in less knee (0.001 ≤ p ≤ 0.07) and greater lumbar spine (0.001 ≤ p ≤ 0.35) sagittal motion when lifting. Associated with this compensatory movement strategy were greater L4/L5 anterior/posterior reaction shear forces (0.001 ≤ p ≤ 0.25). However, there were cases when individual compensatory movement strategies differed from the "group" response (i.e., subjects increased their sagittal knee motion on the affected side about 8% of the time); this resulted in increased peak L4/L5 joint compression forces without changing the peak L4/L5 anterior-posterior shear forces. Ankle dysfunction can alter the way in which individuals move and load their low-backs when lifting. The different ways in which individuals compensate for personal movement constraints could alter the potential site and mechanism of occupational low-back injury.

Gait kinematics and passive knee joint range of motion in children with hypermobility syndrome

Hypermobility syndrome (HMS) is characterised by generalised joint laxity and musculoskeletal complaints. Gait abnormalities have been reported in children with HMS but have not been empirically investigated. The extent of passive knee joint range of motion (ROM) has also not been well reported in children with HMS. This study evaluated gait kinematics and passive knee joint ROM in children diagnosed with HMS and healthy controls. Thirty-seven healthy children (mean age ± SD = 11.5 ± 2.6 years) and 29 children with HMS (mean age ± SD = 11.9 ± 1.8 years) participated. Sagittal knee motion and gait speed were evaluated using a VICON 3D motion analysis system. Passive knee ROM was measured with a manual goniometer. Independent t-tests compared the values of sagittal knee motion and gait speed between the two groups. Mann–Whitney U tests compared passive knee ROM between groups. Passive ROM (extension and flexion) was significantly higher (both p < 0.001) in children with HMS than the healthy controls. Peak knee flexion (during loading response and swing phase) during walking was significantly lower (both p < 0.001) in children with HMS. Knee extension in mid stance during walking was significantly increased ( p < 0.001) in children with HMS. However, gait speed was not statistically ( p = 0.496) different between the two groups. Children with HMS had higher passive knee ROM than healthy children and also demonstrated abnormal knee motion during gait. Gait re-education and joint stability exercise programmes may be of value to children with HMS.

Radical Posterior Capsulectomy Improves Sagittal Knee Motion in Crouch Gait

Knee flexion contracture leading to crouch gait is commonly seen in children with myelomeningocele. Progressive increase in knee flexion contracture increases energy cost, which interferes with efficient, functional ambulation. To prevent this, surgical release has been recommended when a knee flexion contracture exceeds 15° to 20°. We therefore asked whether knee flexion contracture release improved dynamic sagittal motion and walking velocity using computerized gait analysis. We retrospectively studied 11 patients (20 knees) with high-sacral-level or low-lumbar-level myelomeningocele and knee flexion contracture of greater than 15°. All patients underwent dynamic gait analysis pre- and postoperatively. Surgery consisted of selective hamstring lengthening (medial and lateral), gastrocnemius release from the femoral condyles, and posterior knee capsulectomy. We observed improvements postoperatively in clinical measurements and sagittal kinematics. The clinical knee flexion contracture improved from a mean of 24.9° preoperatively to 5.9° postoperatively. The knee flexion at initial contact improved from 37.6° to 9.0°, and minimum knee flexion in single-leg stance improved from 48.2° to 16.4. Walking velocity improved from 72.2% to 80.0% of age-matched normal. Surgical treatment of knee flexion contracture in patients with myelomeningocele using radical posterior knee capsulectomy leads to improvement in clinical knee flexion contracture, dynamic sagittal kinematics, and walking velocity.

Rectus Femoris to Gracilis Muscle Transfer With Fractional Lengthening of the Vastus Muscles: A Treatment for Adults With Stiff Knee Gait

Stiff knee gait, which may be seen in patients with upper motor neuron injury, describes a gait pattern with a relative loss of sagittal knee motion. It interferes with foot clearance during swing, often leading to inefficient compensatory mechanisms and ambulatory dysfunction. Distal rectus femoris muscle transfers and fractional lengthening of the vastus muscles have been performed in adult patients. The purpose of this study was to describe a unique surgical technique and report on initial outcomes. A retrospective case-series study design was used. The patients were adults with stiff knee gait due to stroke or traumatic brain injury who underwent distal rectus femoris muscle transfer with fractional lengthening of the vastus muscles. The patients (19 men and 18 women) had an average age of 51 years at the time of surgery. Lower-extremity examinations, clinical gait analyses, and satisfaction levels were recorded preoperatively and postoperatively. At a mean follow-up time of 10 months, 36 (97%) of the 37 patients were satisfied with their clinical and functional results, and the average Viosca score improved from 3.1 to 3.5. Limitations of the study include use of a retrospective design, lack of a control group, and limited quantitative measures of gait. Distal rectus femoris muscle transfer and fractional lengthening of the vastus muscles were found to be a possible treatment for adults with stiff-knee gait caused by stroke or traumatic brain injury.

Concepts and measurement of in vivo tibiofemoral kinematics

Recent studies of tibiofemoral kinematics in 6 degrees-of-freedom have given us a new perspective and demonstrated lateral compartmental roll-back centered on a medially oriented axis over a relatively stable medial compartment during functional arcs of sagittal knee motion. This translates into coupled internal tibial rotation with increasing knee flexion, which is altered by anterior cruciate ligament (ACL) injury. During terminal extension, the tensioned ACL provides an internal torque to the lateral femoral condyle with tightening of the lateral collateral ligament , culminating in the ‘screw-home mechanism’. Studies of tibiofemoral kinematics in the ACL-deficient knee have demonstrated posterior and medial shifts of the femur relative to the tibia reference point. In addition, the ACL-deficient knee also demonstrates different patterns of tibiofemoral kinematics during gait. Current ACL-reconstruction techniques will restore some functions of the ACL; however, some studies have suggested that anatomical ACL-reconstruction may better restore normal tibiofemoral kinematics. Although in vitro studies have contributed much to our knowledge of knee kinematics, increasingly accurate in vivo measurement techniques now offer new insight on rotational stability. The methodologies of in vivo kinematics include radiological techniques , video-based motion analysis, electromagnetic tracking devices, and ultrasound-based systems. As management of knee pathologies continue to evolve, development of reliable measures of rotational stability may be the next challenge in clinical and functional outcome assessment.