Knee rotation during a weightbearing activity: influence of turning

Kinetic analysis of tandem gait on a sine-wave-shaped walkway

[Purpose] The purpose of this study was to ascertain the kinetic characteristics on a horizontal plane, including knee joint rotation, when performing tandem gait on a sine-wave walkway. [Participants and Methods] The participants were 10 healthy adults. The movement task included tandem gait on a sine-wave walkway. The instruments used were an electromyograph and a three-dimensional motion analysis system. Regarding data analysis, we determined the knee joint rotation angle and muscle activity of the biceps femoris and semitendinosus muscle. [Results] The knee joint rotation angle range was 48.1 ± 6.7°. Two strategies were confirmed with regard to the direction of knee joint rotation: a case in which the agonist muscle acts actively and a case in which the antagonist muscle acts passively. [Conclusion] It has been suggested that the knee joint rotational angle and muscular activity of the rotator muscle group are important for tandem gait on a sine-wave-shaped walking path.

Mobility of the rotating platform in low contact stress knee arthroplasty is durable

PURPOSE

The mobile bearing or rotating platform (RP) in total knee arthroplasty (TKA) is originally part of a low contact stress (LCS) concept, with bearing undersurface mobility compensating higher bearing upper-surface congruency. The in vivo range of axial femorotibial rotation in RP knees has been the subject of many studies, but always involving the performance of relatively low demanding task conditions. Hardly any study has addressed the maintenance of this rotation over time.

METHODS

Two consecutive series of patients with LCS RP knees were studied in a cross-sectional study of 1- and 5-year follow-up. They were assessed using optoelectronic movement analysis during gait and the performance of a sit-to-walk (STW) task with and without turning steps.

RESULTS

A mean range of rotation (SD) was found in the 1-year group of 13.4° (3.7) during gait, 17.8° (6.8) during STW straight, and 17.9° (6.9) during STW with turning. The range in the 5-year group was 11.2° (6.0) during gait, 18.5° (8.7) during STW straight, and 18.3° (8.3) during STW with turning. A so-called paradoxical axial rotation pattern during gait and STW straight occurred in both groups in a normal prevalence.

CONCLUSION

The amount and pattern of rotation in a LCS RP knee does not become impaired between 1 and 5 years postoperatively. The theoretical benefit of RP TKA has not been proven in any clinical study so far, and studies with suitable long-term follow-up need to prove whether this mobility also leads to improved prosthesis survival. However, our findings support the functioning of the rotating platform at a basal science level and illustrate the need for the use of more complex tasks in kinematic studies.

LEVEL OF EVIDENCE

Therapeutic study, Level III.

Low-Contact-Stress Knee Arthroplasty: Past History or Ahead of Time?

Low-contact-stress mobile-bearing (MB) total knee arthroplasty (TKA) can rely on a long history. Its concept comprises a combination of high condylar congruency and compensatory bearing rotation to promote load sharing. However, other MB designs have become available, and critical points have been raised about the benefit of MB in general. Although there is kinematic and kinetic support for the low-contact-stress concept, there is no tribologic or clinical proof of its superiority over fixed-bearing concepts. Further study should be controlled for differences in polyethylene quality and need to provide a measure of condylar congruency to differentiate authentic low-contact-stress variants form others. [Orthopedics. 2016; 39(3):e402-e412.].

Mobile-bearing total knee arthroplasty: More rotation is evident during more demanding tasks

BACKGROUND

Some reports showed few but significant more axial femorotibial rotation in favor of mobile-bearing (MB) versus fixed-bearing (FB) total knee arthroplasty (TKA), mostly during knee bend fluoroscopic studies. The goal of the current study was to submit MB and FB groups of TKA patients to a turning activity, in which additional rotation was to be expected.

METHODS

Two consecutive cohorts of patients after TKA (10 FB and 11 MB knees in a total of 18 patients) were assessed using motion analysis five year postoperatively, while performing gait and sit-to-walk (STW) movements with and without turning steps.

RESULTS

Mean range of rotation in the FB group increased from 9.7° during gait, to 11.7° during STW straight, and to 14.3° during STW turning. Mean range of rotation in the MB group increased from 13.4° during gait to 21.0° during STW straight, and stayed at 21.1° during STW turning.

CONCLUSIONS

Too many uncontrolled variables in the current study hinder a meaningful discrimination of MB from FB TKA rotation. However, the study does illustrate how more demanding task loads could be helpful in exploring the geometric constraints of TKA variants.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Analysis of a rotary task following total knee arthroplasty: Stair descent with a cross-over turn

Leg loading and knee angle differences have been reported in total knee replacement individuals during straight gait; however, little is known about the impact on the knee during turning. Rotary motions may be difficult following total knee replacement surgery; therefore, some individuals may develop strategies or utilize pre-surgical strategies in order to maintain function. The primary aim of this study was to identify differences in individuals with a total knee replacement as compared to their healthy counterparts during stair descent followed by a cross-over turn. Ground reaction force, knee angle and moments were recorded on 10 total knee replacement and 12 healthy individuals during stair descent followed by a turn and compared to walking straight. Variables were analyzed for the affected, unaffected and healthy knees during the gait cycle. On initial contact, the total knee replacement group had less ground reaction force on the affected leg compared to the unaffected leg (p = 0.021) and had delayed contact (p = 0.044) and a slower loading rate (p = 0.020) compared to healthy group. During mid-stance, the affected leg had less ground reaction force compared to the healthy leg (p = 0.049). The affected stance leg had less knee flexion during mid-stance in both the straight trial (p = 0.002) and turn (p = 0.010). Moment differed between straight and turn trials but not between groups. Stair descent with or without a turn was approached in a precautionary manner by individuals with a total knee replacement. Slow approach, reduced impact and weight-bearing with a more extended knee on the affected leg may suggest a protective strategy to avoid risk of fall.

Three-Dimensional Knee Kinematics by Conventional Gait Analysis for Eleven Motor Tasks of Daily Living: Typical Patterns and Repeatability

The availability of detailed knee kinematic data during various activities can facilitate clinical studies of this joint. To describe in detail normal knee joint rotations in all three anatomical planes, 25 healthy subjects (aged 22–49 years) performed eleven motor tasks, including walking, step ascent and descent, each with and without sidestep or crossover turns, chair rise, mild and deep squats, and forward lunge. Kinematic data were obtained with a conventional lower-body gait analysis protocol over three trials per task. To assess the repeatability with standard indices, a representative subset of 10 subjects underwent three repetitions of the entire motion capture session. Extracted parameters with good repeatability included maximum and minimum axial rotation during turning, local extremes of the flexion curves during gait tasks, and stride times. These specific repeatable parameters can be used for task selection or power analysis when planning future clinical studies.

Strategies utilized to transfer weight during knee flexion and extension with rotation for individuals with a total knee replacement

Functional activities in daily life can require squatting and shifting body weight during transverse plane rotations. Stability of the knee can be challenging for people with a total knee replacement (TKR) due to reduced proprioception, nonconforming articular geometry, muscle strength, and soft tissue weakness. The objective of this study was to identify strategies utilized by individuals with TKR in double-stance transferring load during rotation and flexion. Twenty-three subjects were recruited for this study: 11 TKR subjects (age: 65 ± 6 years; BMI 27.4 ± 4.1) and 12 healthy subjects (age: 63 ± 7; BMI 24.6 ± 3.8). Each subject completed a novel crossover button push task where rotation, flexion, and extension of the knee were utilized. Each subject performed two crossover reaching tasks where the subject used the opposite hand to cross over their body and press a button next to either their shoulder (high) or knee (low), then switched hands and rotated to press the opposite button, either low or high. The two tasks related to the order they pressed the buttons while crossing over, either low-to-high (L2H) or high-to-low (H2L). Force platforms measured ground reaction forces under each foot, which were then converted to lead force ratios (LFRs) based on the total force. Knee flexion angles were also measured. No statistical differences were found in the LFRs during the H2L and L2H tasks for the different groups, although differences in the variation of the loading within subjects were noted. A significant difference was found between healthy and unaffected knee angles and a strong trend between healthy and affected subject's knee angles in both H2L and L2H tasks. Large variations in the LFR at mid-task in the TKR subjects suggested possible difficulties in maintaining positional stability during these tasks. The TKR subjects maintained more of an extended knee, which is a consistent quadriceps avoidance strategy seen by other researchers in different tasks. These outcomes suggest that individuals with a TKR utilize strategies, such as keeping an extended knee, to achieve rotary tasks during knee flexion and extension. Repeated compensatory movements could result in forces that may cause difficulty over time in the hip joints or low back. Early identification of these strategies could improve TKR success and the return to activities of daily living that involve flexion and rotation.

Joint kinematics following bi-compartmental knee replacement during daily life motor tasks

In many cases knee osteoarthritis leads to total knee replacement surgery (TKR) even if the lateral compartment is not involved. More recently, a bicompartmental knee replacement system (BKR) (Journey Deuce, Smith & Nephew Inc., Memphis, TN, USA) has been developed that only replaces the medial tibiofemoral and the patellofemoral compartments, thus preserving both cruciate ligaments with its associated benefits. However information on the effect of BKR on in vivo knee joint kinematics is not widely available in the literature. Therefore, this study analyzed full three-dimensional knee joint kinematics in 10 postoperative BKR-subjects for a broad spectrum of relevant daily life activities: walking, walking followed by a cross-over or sidestep turn, step ascent and descent, mild squatting and chair rise. We analyzed to what extent normal knee motion is regained through comparison with their non-involved limb as well as a group of matched controls. Furthermore, coefficients of multiple correlation were calculated to assess the consistency of knee joint kinematics both within and between subject groups. This analysis demonstrated that, despite the presence of differences indicative for retention of pre-operative motion patterns and/or remaining compensations, knee joint kinematics in BKR limbs replicate, for a large range of daily-life motor tasks, the kinematics of the contra-lateral non-affected limbs and healthy controls to a similar extent as they are replicated within both these control groups.

Range of motion and repeatability of knee kinematics for 11 clinically relevant motor tasks

Standard gait analysis reports knee joint rotations in the three anatomical planes without addressing their different levels of reliability. Most clinical studies also restrict analysis to knee flexion-extension, because knee abduction-adduction and axial rotation are small with respect to the corresponding amount of measurement artefact. This study analyses a set of 11 motor tasks, in order to identify those that are adequately repeatable and that can induce greater motion at the knee than walking. Ten volunteers (mean ± SD age: 29 ± 9 years) each underwent three motion analysis sessions on different days with a standard gait analysis system and protocol. In each session they performed normal walking, walking with sidestep and crossover turns, ascent onto and descent off a step, descent with sidestep and crossover turns, chair rise, mild and deep squats, and lunge. Range and repeatability of motions in the three anatomical planes were compared by ANOVA. The sidestep turns showed a range of axial rotation significantly larger than that in walking (about 8°), while maintaining similar levels of repeatability. Ascent, chair rise, squat, and lunge showed greater flexion ranges than walking; among these, ascent was the most repeatable. The results show that turning increases knee axial rotation in young subjects significantly. Further, squats and lunges, currently of large interest in orthopaedics and sports research, have smaller repeatability, likely accounted for to the smaller constraints than in the traditional motor tasks.

Análise fluoroscópica da movimentação in vivo do insert na ATJ de plataforma rotatória

OBJETIVO: Confirmar por análise fluoroscópica a movimentação rotacional do insert de polietileno em artroplastias totais de joelho (ATJ) de plataforma rotatória, após um tempo pós operatório mínimo de seis meses, foram estudados 15 joelhos, submetidos a ATJ de plataforma rotatória, com a prótese NEW WAVE, da LEPINE. MÉTODOS: Foi utilizado para a avaliação da rotação do insert de polietileno através de um aparelho de fluoroscopia numa visão anteroposterior do joelho com 90º de flexão. Caso a imagem do marcador radiopaco do polietileno permanecesse inalterada, ou seja, acompanhasse o fêmur, era considerado então que a rotação estaria ocorrendo entre o insert e o componente tibial. RESULTADOS: Dos 15 joelhos analisados, 14 apresentaram movimentação demonstrável do insert de polietileno, totalizando 93,3%. Para que a ATJ de plataforma rotatória mantenha seu potencial é necessário que a movimentação rotacional do insert de polietileno se mantenha com o tempo. CONCLUSÃO: Com estudo dessa amostra concluiu-se que a rotação se mantém de forma consistente (93%). Sugerindo que a ATJ de plataforma rotatória tem efetivamente o potencial de apresentar menor desgaste do polietileno pela maior congruência articular, em relação à ATJ de apoio fixo, além da vantagem de auto-alinhamento do mecanismo extensor.

In vivo weight-bearing kinematics with medial rotation knee arthroplasty

Knee arthroplasties are designed to accommodate flexion, axial rotation and anteroposterior (AP) translation. Axial rotation during extension varies, with some rotating platform devices allowing unrestricted rotation while some conforming fixed-bearing designs almost none. The purpose of this study was to examine in vivo kinematics of a fixed-bearing medial rotation-type arthroplasty (MRK) during weight-bearing activities. Fifteen knees with a medial pivot TKA design were studied during step and pivot activities using lateral fluoroscopy and model-image registration. Average knee kinematics during the step activity showed little AP translation or rotation from 0 degrees -100 degrees flexion. During the pivot activity, the mean tibial internal rotation in individual knees was 7 degrees (3 degrees -19 degrees ). Mean condylar translations for individual knees were 3mm medially and 5mm laterally. The medial pivot prosthesis design provides anteroposterior stability during demanding activities, and exhibits a medial pivot motion pattern when subjected to twisting.