Does knee alignment influence gait in patients with severe knee osteoarthritis?

The role of limb alignment on natural tibiofemoral kinematics and kinetics

Aims

This study aimed to analyze kinematics and kinetics of the tibiofemoral joint in healthy subjects with valgus, neutral, and varus limb alignment throughout multiple gait activities using dynamic videofluoroscopy.

Methods

Five subjects with valgus, 12 with neutral, and ten with varus limb alignment were assessed during multiple complete cycles of level walking, downhill walking, and stair descent using a combination of dynamic videofluoroscopy, ground reaction force plates, and optical motion capture. Following 2D/3D registration, tibiofemoral kinematics and kinetics were compared between the three limb alignment groups.

Results

No significant differences for the rotational or translational patterns between the different limb alignment groups were found for level walking, downhill walking, or stair descent. Neutral and varus aligned subjects showed a mean centre of rotation located on the medial condyle for the loaded stance phase of all three gait activities. Valgus alignment, however, resulted in a centrally located centre of rotation for level and downhill walking, but a more medial centre of rotation during stair descent. Knee adduction/abduction moments were significantly influenced by limb alignment, with an increasing knee adduction moment from valgus through neutral to varus.

Conclusion

Limb alignment was not reflected in the condylar kinematics, but did significantly affect the knee adduction moment. Variations in frontal plane limb alignment seem not to be a main modulator of condylar kinematics. The presented data provide insights into the influence of anatomical parameters on tibiofemoral kinematics and kinetics towards enhancing clinical decision-making and surgical restoration of natural knee joint motion and loading.

Unraveling the gait dynamics - A comparative study of iASSIST and conventional total knee replacement techniques in osteoarthritic elderly patients

Background

Osteoarthritis (OA) stands as the most prevalent disability among the elderly population. Assessing functional outcomes after Total Knee Replacement (TKR) typically involves Gait analysis along with other evaluation methods. The objective of this study was to compare Gait results, including temporospatial parameters, joint angles, gait profile score (GPS), and movement analysis profiles (MAP), between conventional and iASSIST TKR techniques.

Method

The study involved 21 participants (mean age 68.4 ± 4.2 years), with 16 females and 5 males. Among them, 11 patients had traditional surgery (15 TKR), and 10 patients had iASSIST surgery (13 TKR), totaling 28 knees (7 bilateral). The pre-operative Gait analysis was conducted one day before the surgical procedure, whereas the postoperative Gait analysis was performed, on average, 210 ± 20 days after surgery. Gait analysis was conducted using the Qualisys Motion capture system, operating at a rate of 120 Hz. The data were thoroughly analyzed using Visual 3D C-Motion Software.

Results

An analysis of gait biomechanics metrics, encompassing temporospatial parameters, joint angles, GPS, and MAP, was undertaken. Significant differences were observed in sagittal plane joint angles of the pelvis and hip, transverse plane joint angles of the knee, cadence, and MAP of foot internal/external rotation. However, there were no statistically significant differences between the two TKR techniques in the remaining temporospatial variables, joint angles, GPS, or MAP.

Conclusion

This study revealed a significant difference between iASSIST-guided TKR and conventional TKR, demonstrating that the iASSIST procedure led to improvements in walking biomechanics. Findings hold potential utility for orthopedic surgeons in their decision-making processes, ultimately contributing to the improvement of functional outcomes following TKR.

Clinical and radiographic characterization of three-dimensional gait profiles of patients with knee osteoarthritis

BACKGROUND

Previous authors have utilized gait kinematics to categorize knee osteoarthritis patients into four distinct profiles: (1) flexed knee; (2) externally rotated knee; (3) stiff knee; and (4) knee varus thrust and rotational rigidity. However, the relationship between these gait profiles and patients' characteristics remains poorly understood. Thus, this study aimed to investigate whether differences in clinical and radiographic characteristics were associated with these four gait profiles.

METHODS

This cross-sectional study used available data from a previous biomechanical study. Data on the four gait profiles were collected from 42 patients with advanced knee osteoarthritis. Three-dimensional kinematics of the knee was recorded during gait using an optoelectronic system. Subjects were evaluated for knee strength, range of motion, tibial slope, femorotibial angle, radiographic severity, anthropometric measurements, and patient-reported outcomes. Multiple comparisons were made using Dunn's test. The level of significance was set at 5%, and the effect size was calculated.

FINDINGS

Body mass index (BMI) was the only variable associated with a specific gait profile: profile 4 (P = 0.01; effect size = P1 × P4: -0.62; P2 × P4: -0.41; P3 × P4: -0.40).

INTERPRETATION

Our findings suggest that most clinical and radiographic characteristics commonly measured in clinical practice did not differ significantly among knee osteoarthritis patients with the four different gait profiles. The only exception was a higher BMI noted in those with gait profile 4; however, it remains unclear whether it can cause varus thrust or rotation rigidity. The incorporation of three-dimensional motion analysis to identify gait profiles provided clinical insights beyond the limitations of traditional clinical assessments.

The association between tibial torsion, knee flexion excursion and foot progression during gait in people with knee osteoarthritis: a cross-sectional study

BACKGROUND

Lower limb malalignment is associated with gait kinematics, but there is limited information on the relationship between gait kinematics and tibial torsion in individuals with knee osteoarthritis (OA). This study aimed to investigate possible associations between tibial torsion and early stance kinematics during gait in people with mild and moderate medial knee OA.

METHODS

Forty-seven participants (age: 62.1 ± 6.0 years; female/male: 37/10) diagnosed with medial knee OA were recruited from a regional hospital. Thirty of them had mild and seventeen had moderate knee OA. Lower limb alignment including tibial torsion and valgus/varus alignment were assessed by an EOS biplaner X-ray system with participants in weight-bearing position. Lower limb kinematics during gait was captured using the Vicon motion analysis system. The associations were estimated by partial Pearson correlation coefficient test.

RESULTS

Our results indicated that external tibial torsion was related to early stance knee flexion excursion in participants with moderate knee OA (r = -0.58, p = 0.048), but not in participants with mild knee OA (r = 0.34, p = 0.102). External tibial torsion was associated with external foot progression angle (r = 0.48, p = 0.001), and knee varus/valgus alignment was associated with knee flexion excursion (r = -0.39, p = 0.010) in all participants.

CONCLUSIONS

Both horizontal and frontal lower limb alignments were associated with knee flexion excursion at early stance of gait cycle in participants with medial knee OA. The distal rotational profile of lower limb would likely affect knee motion in sagittal plane. It implies that people with moderate knee OA could possibly benefit from correction of rotational alignment of lower limb.

Gait recovery is not associated with meniscus and/or knee ligament injuries following lateral tibial plateau fractures. A prospective 3-year cohort study of 56 patients

INTRODUCTION

Though associated meniscus and/or knee ligament injuries following lateral tibial plateau fractures (TPF) are common, the importance of development in gait recovery is unknown. This study aim to report the 12- and 36-month gait recovery in patients with lateral TPF divided into two groups presenting with and without associated meniscus and/or knee ligament injuries. (Associated meniscus and/or knee ligament injuries were grouped as: 1) missing, 2) lateral or medial menisci, 2) posterior and anterior cruciate ligament (PCL/ACL), and 4) lateral or medial collateral ligament.) HYPOTHESIS: Comparable results at the 12- and 36-month follow-up between groups presenting with and without soft tissue injuries.

PATIENTS AND METHODS

Study design: cohort study. Included were patients admitted following a lateral TPF (AO-type 41 B) between December 1, 2013 and November 30, 2016. The primary outcome score was gait sample.

RESULTS

Fifty-six patients were included. The mean age of the patients at the time of fracture was 56 years (range from 22 to 86). Female gender represents 75%. MRI-verified associated meniscus and/or knee ligament injuries were observed in 28 patients (50%). The average gait speed at the 12- and 36-month follow-up were 125.7 (SD31.3) and 127.7 (SD16.6) cm/sec. for patients with associated meniscus and/or knee ligament injuries and 125.2 (SD31.1) and 130.1 (SD15.6) cm/sec. for patients without associated meniscus and/or knee ligament injuries (p=0.96, p=0.17). Regardless of soft tissue injuries, the development in percent of gait asymmetry for step-length and single-support decrease significantly between the 12- and the 36-month follow-up. (p>0.002) DISCUSSION: This study indicates that gait recovery following lateral TPFs were not associated with associated meniscus and/or knee ligament injuries at the 12- and 36-month follow-up. Between the 12- and 36-month follow-up asymmetry of the gait function decline significantly indicating a prolonged recovery period of gait function following TPFs.

LEVEL OF EVIDENCE

II; prospective cohort study.

Gait biomechanics phenotypes among total knee arthroplasty candidates by machine learning cluster analysis

Knee osteoarthritis patient phenotyping is relevant to developing targeted treatments and assessing the treatment efficacy of total knee arthroplasty (TKA). This study aimed to identify clusters among TKA candidates based on demographic and knee mechanic features during gait, and compare gait changes between clusters postoperatively. TKA patients underwent 3D gait analysis 1-week pre (n = 134) and 1-year post-TKA (n = 105). Principal component analysis was applied to frontal and sagittal knee angle and moment waveforms, extracting major patterns of variability. Age, sex, body mass index, gait speed, and frontal and sagittal pre-TKA angle and moment PC scores previously identified as relevant to TKA outcomes were standardized (mean = 0, SD = 1, [134 × 15]). Multidimensional scaling and machine learning-based hierarchical clustering were applied. Final clusters were validated by examining intercluster differences pre-TKA and gait feature changes (Post_PCscore  - Pre_PCscore ) by k-way Χ² and ANOVA tests. Four TKA candidate phenotypes yielded optimum clustering metrics, interpreted as higher and lower functioning clusters that were predominantly male and female. Higher functioning clusters pre-TKA (clusters 1 and 4) had more dynamic sagittal flexion moment (p < 0.001) and frontal plane adduction moment (p < 0.001) loading/un-loading patterns during stance. Post-TKA, higher functioning clusters demonstrated less knee mechanic improvements during gait (flexion angle p < 0.001; flexion moment p < 0.001). TKA candidates can be characterized by four clusters, predominately separated by sex and knee joint biomechanics. Post-TKA knee kinematics and kinetics improvements were cluster-specific; lower functioning clusters experienced more improvement. Cluster-based patient profiling may aid in triaging and developing OA management and surgical strategies meeting group-level function needs.

Trunk Biomechanics in Individuals with Knee Disorders: A Systematic Review with Evidence Gap Map and Meta-analysis

BACKGROUND

The trunk is the foundation for transfer and dissipation of forces throughout the lower extremity kinetic chain. Individuals with knee disorders may employ trunk biomechanical adaptations to accommodate forces at the knee or compensate for muscle weakness. This systematic review aimed to synthesize the literature comparing trunk biomechanics between individuals with knee disorders and injury-free controls.

METHODS

Five databases were searched from inception to January 2022. Observational studies comparing trunk kinematics or kinetics during weight-bearing tasks (e.g., stair negotiation, walking, running, landings) between individuals with knee disorders and controls were included. Meta-analyses for each knee disorder were performed. Outcome-level certainty was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE), and evidence gap maps were created.

RESULTS

A total of 81 studies investigating trunk biomechanics across six different knee disorders were included (i.e., knee osteoarthritis [OA], total knee arthroplasty [TKA], patellofemoral pain [PFP], patellar tendinopathy [PT], anterior cruciate ligament deficiency [ACLD], and anterior cruciate ligament reconstruction [ACLR]). Individuals with knee OA presented greater trunk flexion during squatting (SMD 0.88, 95% CI 0.58-1.18) and stepping tasks (SMD 0.56, 95% CI 0.13-.99); ipsilateral and contralateral trunk lean during walking (SMD 1.36; 95% CI 0.60-2.11) and sit-to-stand (SMD 1.49; 95% CI 0.90-2.08), respectively. Greater trunk flexion during landing tasks in individuals with PFP (SMD 0.56; 95% CI 0.01-1.12) or ACLR (SMD 0.48; 95% CI 0.21-.75) and greater ipsilateral trunk lean during single-leg squat in individuals with PFP (SMD 1.01; 95% CI 0.33-1.70) were also identified. No alterations in trunk kinematics of individuals with TKA were identified. Evidence gap maps outlined the lack of investigations for individuals with PT or ACLD, as well as for trunk kinetics across knee disorders.

CONCLUSION

Individuals with knee OA, PFP, or ACLR present with altered trunk kinematics in the sagittal and frontal planes. The findings of this review support the assessment of trunk biomechanics in these individuals in order to identify possible targets for rehabilitation and avoidance strategies.

TRIAL REGISTRATION

PROSPERO registration number: CRD42019129257.

Spatiotemporal parameters of the operated and non-operated knees before and after unilateral total knee arthroplasty

BACKGROUND

Knee osteoarthritis is a common condition in various orthopedic clinics and hospitals. The aim of this study was to investigate the effects of unilateral total knee arthroplasty (TKA) application on short and long-term spatiotemporal gait parameters, maximum plantar pressure (MPP), and functional status in patients with knee osteoarthritis.

RESEARCH QUESTION

What is the change process in spatiotemporal parameters without any intervention before and after TKA surgery?

METHODS

This study is a prospective and cross-sectional study. Participants were assessed preoperatively at the 1st week (Pre1W), postoperative 1st month (Post1M) and 6th month (Post6M). Spatiotemporal parameters and MMP were assessed using the Win Track platform (Medicapteurs Technology, France) and functional states were assessed using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the Lequesne Index.

RESULTS

Significant improvements were found in the WOMAC and Lequesne Index values in the Post1M and Post6M periods compared to the preoperative period. However, the improvement in WOMAC and Lequesne Index scores in the Post6M period was significant compared to the scores in the Post1M period (p < 0.01). Spatiotemporal parameters deteriorated in the Post1M period, while improvements were observed in the Post6M period. We observed that patients had worse gait parameters in the near postoperative period than before surgery. It was the period with the greatest improvements in long-term outcomes.

SIGNIFICANCE

In the light of our study results, we think that early gait disturbances in patients who underwent direct TKA may be caused by physiological processes. Therefore, we believe that there is no need for any intervention for gait disorders that occur in the early postoperative period.

The effect of increasing trunk flexion during normal walking

BACKGROUND

The head, arms and trunk segment constitute a large proportion of the body's mass. Therefore, small alterations in trunk inclination may affect lower limb joint moments and muscle activation patterns. Although previous research has investigated the effect of changing frontal plane inclination of the trunk, it is not clear how increasing trunk flexion will impact on the activation of the lower limb muscles.

RESEARCH QUESTION

What is the effect of independently manipulating trunk flexion angle on lower limb kinematics, moments and muscle function?

METHODS

Gait analysis was carried out on 20 healthy people under four trunk flexion conditions: normal walking (NW), NW-5°, NW+5° and NW+10°. For the latter three conditions, a biofeedback approach was used to tightly control trunk flexion angle. A linear mixed model was used to investigate the effect of changing trunk flexion on joint angles, moments, and knee muscle activation.

RESULTS

There were clear increases in hip and ankle moments as trunk flexion was increased, but no change in knee moments. The results also showed a linear increase in knee flexor muscle activity and a corresponding increase in co-contraction as trunk flexion increased. Interestingly, there was a dramatic change in the profile of hamstring activity. In the medial hamstrings, this change led to a 100% increase in activation during early stance as flexion was increased by 5° from NW.

SIGNIFICANCE

This is the first study to demonstrate a strong dependence of knee flexor muscle activity on trunk flexion. This is important as people with knee osteoarthritis have been observed to walk with elevated muscle activation and this has been linked to increased joint loads. It is possible that these altered muscle patterns may result from increased trunk flexion during walking.

How does normal variability in trunk flexion affect lower limb muscle activity during walking?

A large proportion of the mass of the body is contained within the trunk segment. Therefore, small changes in the inclination of this segment have the potential to influence the direction of the ground reaction force and alter lower limb joint moments and muscle activation patterns during walking. The aim of this study was to investigate if variability in sagittal trunk inclination in healthy participants is associated with differences in lower limb biomechanics. Gait analysis data was collected on 41 healthy participants during walking. Two groups were defined based on habitual trunk flexion angle during normal walking, a forward lean group (n = 18) and a backward lean group (n = 17). Lower limb moments, muscle activation patterns and co-contraction levels were compared between the two groups using independent t-tests. The forward lean group walked with 5° more trunk flexion than the backward lean group. This difference was associated with a larger peak hip moment (effect size = 0.7) and higher activation of the lateral gastrocnemius (effect size =0.6) and the biceps femoris (effect size =0.7) muscles. The forward lean group also exhibited greater co-contraction in late stance (effect size =0.7). This is the first study to demonstrate that small differences in trunk flexion are associated with pronounced alterations in the activation of the lateral knee flexor muscles. This is important because people with knee osteoarthritis have been observed to walk with increased trunk flexion. It is possible that increased sagittal trunk inclination may be associated with elevated joint loads in people with knee osteoarthritis.

The influence of knee joint geometry and alignment on the tibiofemoral load distribution: A computational study

BACKGROUND

Deviations in knee joint geometry and alignment were previously related to an increased risk for knee OA. These were hypothesized to influence the load distribution over the articular cartilage. Therefore, this study evaluated the effect of altered knee joint geometry and alignment in the coronal and transverse plane on the medial-lateral load distribution and ligament strain using a musculoskeletal modeling approach.

METHODS

Joint kinematics during gait were measured in 15 healthy adults. Using different musculoskeletal models with altered geometry of the tibia plateau or knee joint malalignment in the coronal and transverse plane, the resulting muscle, ligament and contact forces were calculated. Next, the distribution of the load over the medial and lateral condyle was analyzed and compared to the reference loading distribution, with neutral geometry and alignment, using repeated-measures ANOVA and individual t-tests, with a Bonferroni-corrected alpha level.

RESULTS

Coronal plane malalignment significantly affected the load distribution. Small changes in coronal tibial slope had less pronounced effects on the load distribution, but increased ligament strains. Transverse plane malalignment only minimally affected the load distribution.

CONCLUSION

Coronal plane knee malalignment affected knee loading, with increased varus alignment resulting in increased medial loading. This confirms a causal relation between coronal malalignment and increased medial compartment loading and suggests a potential role of aberrant coronal plane alignment on OA initiation. Altered coronal tibial slope induced increased ligament strains, potentially contributing to a cascade of knee laxity and subsequently more extreme knee malalignment.

Trunk flexion during walking in people with knee osteoarthritis

BACKGROUND

Over 50% of the body's mass is concentrated within the head, arms and trunk. Thus, small deviations in the orientation of the trunk, during normal walking, could influence the position of the centre of mass relative to the lower limb joint centres and impact on lower limb biomechanics. However, there are minimal data available on sagittal kinematics of the trunk in people with knee osteoarthritis (OA) during walking.

RESEARCH QUESTION

Do people with knee OA have altered kinematic patterns of the trunk, pelvis or hip compared with healthy control participants during walking?

METHODS

Statistical parametric mapping was used to compare sagittal and frontal plane kinematic patterns, during walking, between a healthy group and cohort of people with knee OA.

RESULTS

Individuals with knee OA walked with a mean increase in trunk flexion of 2.6°. Although this difference was more pronounced during early stance, it was maintained across the whole of stance phase. There were no differences, between the groups, in sagittal plane pelvic or hip kinematics. There were also no differences in trunk, pelvic or hip kinematics in the frontal plane.

SIGNIFICANCE

Most previous gait research investigating trunk motion in people with knee OA has focused on the frontal plane. However, our data suggest that an increase in sagittal trunk flexion may be a clinical hallmark of people with this disease. Altered trunk flexion could affect joint moments and muscle patterns and therefore our results motivate further research in this area.

Correlation between preoperative imaging parameters and postoperative basic kinematics-based functional outcome in patients with tibial plateau fractures

BACKGROUND

Functional scores and radiographs are often used to assess function and predict development of osteoarthritis in patients with multi-fragmentary tibial plateau fractures (TPFs). Locomotion, which is the primary goal of fracture treatment, is rarely assessed. The objective of this study was to assess functional ability of patients after TPF fixation using spatio-temporal gait analysis (STGA), and to compare STGA variables with self-reported functional scores and preoperative fracture characteristics.

METHODS

Preoperative CT scans of 21 patients with complete articular multi-fragmentary TPFs were evaluated for number of fragments, maximum gap between the fragments and maximum articular depression. All patients underwent STGA (velocity, cadence, step length of the affected and the unaffected leg, single-limb support by the affected and the unaffected leg, and double-leg support) and filled the Knee Society Score and the Short Form-12 questionnaires on average 3 years (SD = 1.56, range, 2-5.8) post-injury.

FINDINGS

Step length and single-limb support time of the affected leg were shorter compared to the unaffected leg (p = 0.02 and p = 0.007, respectively). Number of fracture fragments correlated with cadence (R = -0.461, p = 0.04) and velocity (R = -0.447, p = 0.04).

INTERPRETATION

Given that both higher fracture comminution and deformity on the one hand and the above gait parameter alterations on the other hand are associated with knee osteoarthritis, STGA may be used for routine postoperative evaluation of patients after TPF fixation.

Proximal gait adaptations in individuals with knee osteoarthritis: A systematic review and meta-analysis

Clarifying proximal gait adaptations as a strategy to reduce knee joint loading and pain for individuals with knee osteoarthritis (OA) contributes to understanding the pathogenesis of multi-articular OA changes and musculoskeletal pain in other joints. We aimed to determine whether biomechanical alterations in knee OA patients during level walking is increased upper trunk lean in the frontal and sagittal planes, and subsequent alteration in external hip adduction moment (EHAM) and external hip flexion moment (EHFM). A literature search was conducted in PubMed, PEDro, CINAHL, and Cochrane CENTRAL through May 2018. Where possible, data were combined into a meta-analysis; pooled standardized mean differences (SMD) of between knee OA patients and healthy adults were calculated using a random-effect model. In total, 32 articles (2037 participants, mean age, 63.0 years) met inclusion criteria. Individuals with knee OA had significantly increased lateral trunk lean toward the ipsilateral limb (pooled SMD: 1.18; 95% CI: 0.59, 1.77) along with significantly decreased EHAM. These subjects also displayed a non-significantly increased trunk/pelvic flexion angle and EHFM. The GRADE approach judged all measures as "very low." These results may indicate that biomechanical alterations accompanying knee OA are associated with increased lateral trunk lean and ensuing alterations in EHAM. Biomechanical alterations in the sagittal plane were not evident. Biomechanical adaptations might have negative sequelae, such as secondary hip abductor muscle weakness and low back pain. Thus, investigations of negative sequelae due to proximal gait adaptations are warranted.

Subjects with medial and lateral tibiofemoral articular cartilage defects do not alter compartmental loading during walking

BACKGROUND

Healthy cartilage is essential for optimal joint function. Although, articular cartilage defects are highly prevalent in the active population and hamper joint function, the effect of articular cartilage defects on knee loading is not yet documented. Therefore, the present study compared knee contact forces and pressures between patients with tibiofemoral cartilage defects and healthy controls. Potentially this provides additional insights in movement adaptations and the role of altered loading in the progression from defect towards OA.

METHODS

Experimental gait data collected in 15 patients with isolated cartilage defects (8 medial involvement, 7 lateral-involvement) and 19 healthy asymptomatic controls was processed using a musculoskeletal model to calculate contact forces and pressures. Differences between two patient groups and controls were evaluated using Kruskal-Wallis tests and individually compared using Mann-Whitney-U tests (alpha <0.05).

FINDINGS

The patients with lateral involvement walked significantly slower compared to the healthy controls. No movement adaptations to decrease the loading on the injured condyle were observed. Additionally, the location of loading was not significantly affected.

INTERPRETATION

The current results suggest that isolated cartilage defects do not induce significant changes in the knee joint loading distribution. Consequently, the involved condyle will capture a physiological loading magnitude that should however be distributed over the cartilage surrounding the defect. This may cause local degenerative changes in the cartilage and in combination with inflammatory responses, might play a key role in the progression from articular cartilage defect to a more severe OA phenotype.

Gait analysis following medial opening-wedge high tibial osteotomy

PURPOSE

High tibial osteotomy (HTO) is used to treat young and active patients with knee osteoarthritis (OA) and varus deformity. The medial compartment OA alters the patients' gait.

METHODS

A prospective study was carried out in 21 consecutive patients operated for HTO due to knee OA with varus deformity. There were 14 men and 7 women, with a median age of 51.9 years (38-64). Their gait was analyzed preoperatively and at 1 year postoperatively, and compared to a healthy control group. Clinical assessment (KOOS, WOMAC, Lysholm, and SF-36 scores) was also performed preoperatively and postoperatively.

RESULTS

Patients with medial compartment OA had altered gait relative to the control population. Their walking speed was slower, step length was shorter, and single-leg stance time was shorter, while the double-leg stance time was longer (P < 0.001). Step width was not different between the two groups preoperatively (n.s.), but it was wider in the patient group postoperatively (P = 0.003). There were no differences in the patients' gait parameters before and after the osteotomy (n.s.). However, there was an improved perception of walking so that it is no longer different from controls (n.s.). The KOOS, WOMAC, Lysholm and SF-36 scores improved after HTO. The preoperative median of 7° varus (1-11) was corrected to 3° valgus (0-6).

CONCLUSION

Medial compartment OA with varus deformity leads to gait modifications. HTO does not alter the time-distance parameters of gait; however, patients have improved perception of their walking ability. HTO leads to excellent results for knee function, and improves quality of life without modifying the gait pattern.

LEVEL OF EVIDENCE

II.

Frontal Plane Tibiofemoral Alignment is Strongly Related to Compartmental Knee Joint Contact Forces and Muscle Control Strategies During Stair Ascent

Static frontal plane tibiofemoral alignment is an important factor in dynamic knee alignment and knee adduction moments (KAMs). However, little is known about the relationship between alignment and compartment contact forces or muscle control strategies. The purpose of this study was to estimate medial (MCF) and lateral (LCF) compartment knee joint contact forces and muscle forces during stair ascent using a musculoskeletal model implementing subject-specific knee alignments. Kinematic and kinetic data from 20 healthy individuals with radiographically confirmed varus or valgus knee alignments were simulated using alignment specific models to predict MCFs and LCFs. Muscle forces were determined using static optimization. Independent samples t-tests compared contact and muscle forces between groups during weight acceptance and during pushoff. The varus group exhibited increased weight acceptance peak MCFs, while the valgus group exhibited increased pushoff peak LCFs. The varus group utilized increased vasti muscle forces during weight acceptance and adductor forces during pushoff. The valgus group utilized increased abductor forces during pushoff. The alignment-dependent contact forces provide evidence of the significance of frontal plane knee alignment in healthy individuals, which may be important in considering future knee joint health. The differing muscle control strategies between alignments detail-specific neuromuscular responses to control frontal plane knee loads.

Effects of toe-in and toe-in with wider step width on level walking knee biomechanics in varus, valgus, and neutral knee alignments

BACKGROUND

Increased peak external knee adduction moments exist for individuals with knee osteoarthritis and varus knee alignments, compared to healthy and neutrally aligned counterparts. Walking with increased toe-in or increased step width have been individually utilized to successfully reduce 1st and 2nd peak knee adduction moments, respectfully, but have not previously been combined or tested among all alignment groups. The purpose of this study was to compare toe-in only and toe-in with wider step width gait modifications in individuals with neutral, valgus, and varus alignments.

METHODS

Thirty-eight healthy participants with confirmed varus, neutral, or valgus frontal-plane knee alignment through anteroposterior radiographs, performed level walking in normal, toe-in, and toe-in with wider step width gaits. A 3×3 (group×intervention) mixed model repeated measures ANOVA compared alignment groups and gait interventions (p<0.05).

RESULTS

The 1st peak knee adduction moment was reduced in both toe-in and toe-in with wider step width compared to normal gait. The 2nd peak adduction moment was increased in toe-in compared to normal and toe-in with wider step width. The adduction impulse was also reduced in toe-in and toe-in with wider step width compared to normal gait. Peak knee flexion and external rotation moments were increased in toe-in and toe-in with wider step width compared to normal gait.

CONCLUSION

Although the toe-in with wider step width gait seems to be a viable option to reduce peak adduction moments for varus alignments, sagittal, and transverse knee loadings should be monitored when implementing this gait modification strategy.

Three-dimensional knee kinematic analysis during treadmill gait: Slow imposed speed versus normal self-selected speed

Objectives

Whilst gait speed is variable between healthy and injured adults, the extent to which speed alone alters the 3D in vivo knee kinematics has not been fully described. The purpose of this prospective study was to understand better the spatiotemporal and 3D knee kinematic changes induced by slow compared with normal self-selected walking speeds within young healthy adults.

Methods

A total of 26 men and 25 women (18 to 35 years old) participated in this study. Participants walked on a treadmill with the KneeKG system at a slow imposed speed (2 km/hr) for three trials, then at a self-selected comfortable walking speed for another three trials. Paired t-tests, Wilcoxon signed-rank tests, Mann-Whitney U tests and Spearman’s rank correlation coefficients were conducted using Stata/IC 14 to compare kinematics of slow versus self-selected walking speed.

Results

Both cadence and step length were reduced during slow gait compared with normal gait. Slow walking reduced flexion during standing (10.6° compared with 13.7°; p < 0.0001), and flexion range of movement (ROM) (53.1° compared with 57.3°; p < 0.0001). Slow walking also induced less adduction ROM (8.3° compared with 10.0°; p < 0.0001), rotation ROM (11.4^° compared with 13.6^°; p < 0.0001), and anteroposterior translation ROM (8.5 mm compared with 10.1 mm; p < 0.0001).

Conclusion

The reduced spatiotemporal measures, reduced flexion during stance, and knee ROM in all planes induced by slow walking demonstrate a stiff knee gait, similar to that previously demonstrated in osteoarthritis. Further research is required to determine if these characteristics induced in healthy knees by slow walking provide a valid model of osteoarthritic gait.

Cite this article: N. Mannering, T. Young, T. Spelman, P. F. Choong. Three-dimensional knee kinematic analysis during treadmill gait: Slow imposed speed versus normal self-selected speed. Bone Joint Res 2017;6:514–521. DOI: 10.1302/2046-3758.68.BJR-2016-0296.R1.

Asymmetry in gait pattern following bicondylar tibial plateau fractures-A prospective one-year cohort study

INTRODUCTION

Despite the high number of studies evaluating outcomes following tibial plateau fractures, the literature lacks studies including the objective assessment of gait pattern. The purpose of the present study was to evaluate asymmetry in gait patterns at 12 months after frame removal following ring fixation of a tibial plateau fracture.

PATIENTS AND METHODS

The study design was a prospective cohort study. The primary outcome measurement was the gait patterns 12 months after frame removal measured with a pressure-sensitive mat. The mat registers footprints and present gait speed, cadence, as well as temporal and spatial parameters of the gait cycle. Gait patterns were compared to a healthy reference population.

RESULTS

Twenty-three patients were included with a mean age of 54.4 years (32-78 years). Patients presented with a shorter step-length of the injured leg compared to the non-injured leg (asymmetry of 11.3%). Analysis of single-support showed shorter support time of the injured leg compared to the non-injured leg (asymmetry of 8.7%). Moreover, analysis of swing-time showed increased swing-time of the injured leg (asymmetry of 8.9%). Compared to a healthy reference population, increased asymmetry in all gait patterns was observed. The association between asymmetry and health-related quality of life (HRQOL) showed moderate associations (single-support: R=0.50, P=0.03; step-length: R=0.43, P=0.07; swing-time: R=0.46, P=0.05).

CONCLUSION

Compared to a healthy reference population, gait asymmetry is common 12 months after frame removal in patients treated with external ring fixation following a tibial plateau fracture of the tibia.

Gait analysis before and after corrective osteotomy in patients with knee osteoarthritis and a valgus deformity

PURPOSE

In this prospective study, the changes in kinetics and kinematics of gait and clinical outcomes after a varus osteotomy (tibial, femoral or double osteotomy) in patients with osteoarthritis (OA) of the knee and a valgus leg alignment were analysed and compared to healthy subjects.

METHODS

Twelve patients and ten healthy controls were included. Both kinetics and kinematics of gait and clinical and radiographic outcomes were evaluated.

RESULTS

The knee adduction moment increased significantly postoperatively (p < 0.05) and almost similar to the control group. Patients showed less knee and hip flexion/extension motion and moment during gait pre- and postoperatively compared to the controls. A significant improvement was found in WOMAC [80.8 (SD 16.1), p = 0.000], KOS [74.9 (SD 14.7), p = 0.018], OKS [21.2 (SD 7.5), p = 0.000] and VAS-pain [32.9 (SD 20.9), p = 0.003] in all patients irrespective of the osteotomy technique used. The radiographic measurements showed a mean hip knee ankle (HKA) angle correction of 10.4° (95 % CI 6.4°-14.4°).

CONCLUSION

In patients with knee OA combined with a valgus leg alignment, the varus-producing osteotomy is a successful treatment. Postoperatively, the patients showed kinetics and kinematics of gait similar as that of a healthy control group. A significant increase in the knee adduction moment during stance phase was found, which was related to the degree of correction. The HKA angle towards zero degrees caused a medial shift in the dynamic knee loading. The medial shift will optimally restore cartilage loading forces and knee ligament balance and reduces progression of OA or the risk of OA. A significant improvement in all clinical outcomes was also found.

LEVEL OF EVIDENCE

III.

Navigation-based tibial rotation at 90° of flexion is associated with better range of motion in navigated total knee arthroplasty

PURPOSE

In clinical practice, people with better femorotibial rotation in the flexed position often achieve a favourable postoperative maximum flexion angle (MFA). However, no objective data have been reported to support this clinical observation. In the present study, we aimed to investigate the correlation between the amount of intraoperative rotation and the pre- and postoperative flexion angles.

METHODS

Fifty-five patients with varus osteoarthritis undergoing computer-assisted posterior-stabilized total knee arthroplasty (TKA) were enrolled. After registration, rotational stress was applied towards the knee joint, and the rotational angles were recorded by using a navigation system at maximum extension and 90° of flexion. After implantation, rotational stress was applied for a second time, and the angles were recorded once more. The MFA was measured before surgery and 1 month after surgery, and the correlation between the amount of femorotibial rotation during surgery and the MFA was statistically evaluated.

RESULTS

Although the amount of tibial rotation at maximum extension was not correlated with the MFA, the amount of tibial rotation at 90° of flexion after registration was positively correlated with the pre- and postoperative MFA (both p < 0.005). However, no significant relationship was observed between the amount of tibial rotation after implantation and the postoperative MFA (n.s.).

CONCLUSION

The results showed that better femorotibial rotation at 90° of flexion is associated with a favourable postoperative MFA, suggesting that the flexibility of the surrounding soft tissues is an important factor for obtaining a better MFA, which has important clinical relevance. Hence, further evaluation of navigation-based kinematics during TKA may provide useful information on MFA.

LEVEL OF EVIDENCE

Diagnostic studies, development of diagnostic criteria in a consecutive series of patients, and a universally applied "gold" standard, Level II.

Inter-observer and intra-observer reliability of mechanical axis alignment before and after total knee arthroplasty using long leg radiographs

BACKGROUND

Long leg radiographs (LLRs) are commonly performed for assessment of mechanical alignment and operative planning in patients undergoing total knee arthroplasty (TKA). The aim of this study was to determine the inter- and intra-observer reliability of alignment measured by observers of different levels of experience.

METHODS

Forty patients on the waiting list for a TKA had pre- and post-operative standardised LLRs. We analysed the measurements of mechanical axis alignment between an orthopaedic surgeon, a senior orthopaedic registrar, a junior orthopaedic registrar, and a medical student. Reviewers performed blinded measurements on the same computer screen. These measurements were repeated three months later to assess intra-observer reliability. Furthermore high-resolution screens were compared with standard hospital computer screens to investigate whether monitoring quality influenced the accuracy of measurements of alignment.

RESULTS

Inter-observer reliability was high for pre-operative LLRs with an intra-class correlation (ICC) of >0.9 at all experience levels. Post-operative ICC was lowest between the surgeon and the medical student at 0.7. Intra-observer reliability was high at all experience levels. Larger deformities appeared to have exaggerated measurements for both pre- and post-operative images. There appeared to be no effect of the monitor size and quality on the accuracy of measurement.

CONCLUSIONS

Long leg radiographs can be used to measure mechanical axis alignment with strong reliability across different levels of experience. This information is important for the evaluation of knee alignment measurements in current clinical practice, to assess severity of deformity and to accompany pre-operative planning and post-operative evaluation.

LEVEL OF EVIDENCE

III.

Functional gain following knee replacement in patients aged 75 and older: a prospective follow-up study

BACKGROUND AND AIMS

The aim of this prospective follow-up study was to analyze which patient characteristics predict better functional ability, as well as improvement in the ability, following knee replacement in the aged. The focus was on the impact of specific comorbidities and radiologic data.

METHODS

Knee osteoarthritis patients aged ≥75 years (n = 167) scheduled for knee replacement answered to a questionnaire asking about performance in the activities of daily living (ADL) before the operation, and 1 year afterwards. Radiologic data were evaluated from the latest radiographs, and comorbidity data from patient records. The primary outcome was a sum score indicating how many ADLs (out of 10) the patient was able to perform without difficulty. The factors associated with ADL performance were analyzed with adjustment for age, gender, Charlson's comorbidity index and Kellgren-Lawrence score.

RESULTS

Knee replacement resulted in improved performance in almost all the analyzed ADL activities. Except for cardiac diseases, the effect of the analyzed comorbidities on ADL performance was not significant. Older patients and women attained lower final functional ability than younger patients and men, but improved similarly. In more progressed osteoarthritis, the final ability was lower, but the improvement gained was greater.

CONCLUSIONS

Comorbidity, age, or more progressed osteoarthritis should not be considered an impediment to knee replacement. Even though the final functional ability may be lower in some, the improvement gained by surgery is similar regardless of comorbidity, and was more pronounced in more progressed disease.

Intraoperative passive knee kinematics during total knee arthroplasty surgery

Surgical navigation systems for total knee arthroplasty (TKA) surgery are capable of capturing passive three-dimensional (3D) angular joint movement patterns intraoperatively. Improved understanding of patient-specific knee kinematic changes between pre and post-implant states and their relationship with post-operative function may be important in optimizing TKA outcomes. However, a comprehensive characterization of the variability among patients has yet to be investigated. The objective of this study was to characterize the variability within frontal plane joint movement patterns intraoperatively during a passive knee flexion exercise. Three hundred and forty patients with severe knee osteoarthritis (OA) received a primary TKA using a navigation system. Passive kinematics were captured prior to (pre-implant), and after prosthesis insertion (post-implant). Principal component analysis (PCA) was used to capture characteristic patterns of knee angle kinematics among patients, to identify potential patient subgroups based on these patterns, and to examine the subgroup-specific changes in these patterns between pre- and post-implant states. The first four extracted patterns explained 99.9% of the diversity within the frontal plane angle patterns among the patients. Post-implant, the magnitude of the frontal plane angle shifted toward a neutral mechanical axis in all phenotypes, yet subtle pattern (shape of curvature) features of the pre-implant state persisted.

Evolution of knee kinematics three months after total knee replacement

In patients with debilitating knee osteoarthritis, total knee replacement is the most common surgical procedure. Numerous studies have demonstrated that knee kinematics one year after total knee replacement are still altered compared to the healthy joint. However, little is known regarding impairments and functional limitations of patients several months after total knee replacement. The aim of this study was to describe the evolution of the knee gait kinematic in patients with knee osteoarthritis before and three months after a total knee replacement. Ninety patients who were to undergo total knee replacement were included in this study. Twenty-three subjects were recruited as the control group. Three-dimensional gait analysis was performed before and three months after surgery. The spatio-temporal parameters and three-dimensional knee kinematics for the operated limb were evaluated during a comfortable gait and compared between groups (the before and after surgery groups and the control group). Three months after surgery, patients always walk with a slower gait velocity and lower knee flexion-extension movements compared to the control group. However, a degree of progress was observed in term of the stride and step length, gait velocity and knee alignment in the coronal plane. Our results suggest that the disability is still significant for most patients three months after total knee replacement. A better understand of the impairments and functional limitations following surgery would help clinicians design rehabilitation programs. Moreover, patients should be informed that rehabilitation after total knee replacement is a long process.

Immediate effects of an elastic knee sleeve on frontal plane gait biomechanics in knee osteoarthritis

INTRODUCTION

Osteoarthritis of the knee affects millions of people. Elastic knee sleeves aim at relieving symptoms. While symptomatic improvements have been demonstrated as a consequence of elastic knee sleeves, evidence for biomechanical alterations only exists for the sagittal plane. We therefore asked what effect an elastic knee sleeve would have on frontal plane gait biomechanics.

METHODS

18 subjects (8 women, 10 men) with osteoarthritis of the medial tibiofemoral joint walked over ground with and without an elastic knee sleeve. Kinematics and forces were recorded and joint moments were calculated using an inverse dynamics approach. Conditions with sleeve and without sleeve were compared with paired t-Tests.

RESULTS

With the sleeve, knee adduction angle at ground contact was reduced by 1.9 ± 2.1° (P = 0.006). Peak knee adduction was reduced by 1.5 ± 1.6° (P = 0.004). The first peak knee adduction moment and positive knee adduction impulse were decreased by 10.1% (0.74 ± 0.9 Nm • kg-1; P = 0.002) and 12.9% (0.28 ± 0.3 Nm • s • kg-1; P < 0.004), respectively.

CONCLUSION

Our study provides evidence that wearing an elastic knee sleeve during walking can reduce knee adduction angles, moments and impulse in subjects with knee osteoarthritis. As a higher knee adduction moment has previously been identified as a risk factor for disease progression in patients with medial knee osteoarthritis, we speculate that wearing a knee sleeve may be beneficial for this specific subgroup.

Effect of lower limb malalignment in the frontal plane on transverse plane mechanics during gait in young individuals with varus knee alignment

BACKGROUND

Varus knee alignment has been identified as a risk factor for the progression of medial knee osteoarthritis (OA). This study tested the hypothesis that not only frontal plane kinematics and kinetics but also transverse plane lower extremity mechanics during gait are affected by varus malalignment of the knee.

METHODS

Eighteen, otherwise healthy children and adolescents with varus malalignment of the knee were studied to examine the association between static varus malalignment and functional gait parameters. Kinematic data were collected using a Vicon motion capture system (Vicon Motion Systems, Oxford, UK). Two AMTI force plates (Advanced Mechanical Technology, Inc., Watertown, MA, USA) were used to collect kinetic data.

RESULTS

The results indicated that changes in transverse plane mechanics occur concomitantly with changes in knee malalignment in the frontal plane. A mechanical consequence of varus knee malalignment is obviously an increased endorotation of the foot (internal foot placement) and an increased internal knee rotation (tibia rotation) during stance phase. The linear correlation between the maximum external knee adduction moment in terminal stance and the internal knee rotation in terminal stance (r=0.823, p<0.001) shows that this transverse plane gait mechanics is directly in conjunction with intrinsic compressive load on the medial compartment during gait.

CONCLUSIONS

Understanding factors that influence dynamic knee joint loading in healthy, varus malaligned knees may help us to identify risk factors that lead to OA. Thus, three-dimensional gait analysis could be used for clinical prognoses regarding the onset or progression of medial knee OA.

Associations between gait and clinical parameters in patients with severe knee osteoarthritis: a multiple correspondence analysis

BACKGROUND

Given the complexity of the gait of patients with knee osteoarthritis, a multiple correspondence analysis may be helpful to optimise the extraction of relevant gait and clinical information. Therefore, the aims of this study are to identify the main associations with clinical and gait biomechanical parameters and to evaluate whether there are more specific knee osteoarthritis groups with different gait profiles.

METHODS

Ninety patients with severe knee osteoarthritis and twenty-six healthy individuals participated in this study. Pain and function were assessed with the WOMAC Index; knee joint deformity was assessed by the hip-knee-ankle angle on full-limb radiography; and full body gait analysis was performed with a motion analysis system and force plates.

FINDINGS

Using multiple correspondence analysis, two categories of gait parameters that best explain the gait variance of patients with knee osteoarthritis were highlighted. The forward displacement category is composed of the parameters speed, stride length, hip flexion and knee flexion. The frontal category is composed of the parameters thorax obliquity and knee adductor moments. Moreover, based on these parameters, four distinct gait profiles were identified: two gait profiles were associated with knee varus deformities, increased thorax obliquity and different forward displacements, while two gait profiles were associated with valgus deformities and different forward displacements.

INTERPRETATION

These gait parameters can be used to simplify the characterisation of the gait of the knee osteoarthritis population. Patients in varus profiles increase thorax obliquity on the stance limb and may reduce forward displacement. Patients in valgus profiles, however, only reduce forward displacement.

Timely diagnosis of malalignment of the distal extremities is crucial in morbidly obese juveniles

BACKGROUND/AIMS

To determine i) whether obesity in childhood can be related to malalignment of the distal extremities, ii) the proportion of genu valgum malalignment and abduction setting, and iii) the respective deviation dominance in children who are morbidly obese.

METHODS

31 morbidly obese Caucasian children (16 males) recruited for the STYJOBS Study (ClinicalTrials.gov Identifier NCT00482924) with a mean age of 13.9 ± 0.5 years, a mean height of 162.3 ± 2.7 cm, a mean weight of 90.62 ± 5.0 kg, and a mean BMI of 33.8 ± 1.2 kg/m(2) were clinically examined using the Mikulicz line in order to assess load distribution on the knee joint. 21 participants received a whole-leg X-ray because of a clinically estimated malalignment.

RESULTS

8/31 participants examined were diagnosed with genu valgum, 1/31 with genu varum, and 22/31 did not have any malalignment of the femur or tibia. The majority of genu valgum presentation was due to femoral deviation. Of those without malalignment, 4/22 participants had an abduction setting, while 2/22 showed an adduction of the leg.

CONCLUSION

Genu valgum as a predominant malalignment of the distal extremities is frequent in youth with morbid obesity. Timely guided correction of angular deformity of the knee seems pivotal in order to avoid osteotomy or osteoarthritis later in life.