Rectus femoris surgery for the correction of stiff knee gait in cerebral palsy: A systematic review and meta-analysis

INTRODUCTION

Rectus femoris (RF) transfer was long the gold-standard treatment for stiff knee gait (SKG), but efficacy now seems less than that of distal RF release. The aim of the present study was to compare efficacy between the two. The study hypothesis was that both significantly improve 4 knee kinematic parameters at 1 year.

PATIENTS AND METHOD

A meta-analysis was performed, using PRISMA criteria, on the Medline, Science Direct, Cochrane Registry, Scopus and Pascal databases. Search was conducted up to March 1, 2020 by two authors (A.J & M.T). Study methodology was assessed on MINORS index. Inclusion criteria comprised patients with SKG, treated by RF transfer or distal release. Endpoints comprised: Peak Knee Flexion in swing phase (PKFSW), Knee Range of Motion (KROM), time to Peak Knee Flexion (t-PKFGC), and Maximum Knee Extension in stance phase (MKEST). Effect size was assessed on Standard Mean Deviation (SMD).

RESULTS

A total of 695 studies were identified, 16 of which were included: 14 transfer, 5 release. Data were analyzed for 1,079 limbs in 768 patients. Only transfer improved PKFSW, with small effect size (SMD=0.29). The other three parameters were improved by both techniques, with moderate effect size.

DISCUSSION

Results showed improved knee kinematics after RF transfer, but with small or moderate effect size. The effect of distal release on PKF could not be assessed, due to publication bias. The heterogeneity of studies and low levels of evidence call for caution in interpreting the present results.

LEVEL OF EVIDENCE

III.

Muscle contributions to pre-swing biomechanical tasks influence swing leg mechanics in individuals post-stroke during walking

Background

Successful walking requires the execution of the pre-swing biomechanical tasks of body propulsion and leg swing initiation, which are often impaired post-stroke. While excess rectus femoris activity during swing is often associated with low knee flexion, previous work has suggested that deficits in propulsion and leg swing initiation may also contribute. The purpose of this study was to determine underlying causes of propulsion, leg swing initiation and knee flexion deficits in pre-swing and their link to stiff knee gait in individuals post-stroke.

Methods

Musculoskeletal models and forward dynamic simulations were developed for individuals post-stroke (n = 15) and healthy participants (n = 5). Linear regressions were used to evaluate the relationships between peak knee flexion, braking and propulsion symmetry, and individual muscle contributions to braking, propulsion, knee flexion in pre-swing, and leg swing initiation.

Results

Four out of fifteen of individuals post-stroke had higher plantarflexor contributions to propulsion and seven out of fifteen had higher vasti contributions to braking on their paretic leg relative to their nonparetic leg. Higher gastrocnemius contributions to propulsion predicted paretic propulsion symmetry (p = 0.005) while soleus contributions did not. Higher vasti contributions to braking in pre-swing predicted lower knee flexion (p = 0.022). The rectus femoris had minimal contributions to lower knee flexion acceleration in pre-swing compared to contributions from the vasti. However, for some individuals with low knee flexion, during pre-swing the rectus femoris absorbed more power and the iliopsoas contributed less power to the paretic leg. Total musculotendon work done on the paretic leg in pre-swing did not predict knee flexion during swing.

Conclusions

These results emphasize the multiple causes of propulsion asymmetry in individuals post-stroke, including low plantarflexor contributions to propulsion, increased vasti contributions to braking and reliance on compensatory mechanisms. The results also show that the rectus femoris is not a major contributor to knee flexion in pre-swing, but absorbs more power from the paretic leg in pre-swing in some individuals with stiff knee gait. These results highlight the need to identify individual causes of propulsion and knee flexion deficits to design more effective rehabilitation strategies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-022-01029-z.

The effect of asymmetrical gait induced by unilateral knee brace on the knee flexor and extensor muscles

Asymmetrical stiff knee gait is a mechanical pathology that can disrupt lower extremity muscle coordination. A better understanding of this condition can help identify potential complications. This study proposes the use of dynamic musculoskeletal modelling simulation to investigate the effect of induced mechanical perturbation on the kneeand to examine the muscle behaviour without invasive technique. Thirty-eight healthy participants were recruited. Asymmetrical gait was simulated using knee brace. Knee joint angle, joint moment and knee flexor and extensor muscle forces were computed using OpenSim. Differences inmuscle force between normal and abnormal conditions were investigated using ANOVA and Tukey-Kramer multiple comparison test.The results revealed that braced knee experienced limited range of motion with smaller flexion moment occuring at late swing phase. Significant differences were found in all flexormuscle forces and in several extensor muscle forces (p<0.05). Normal knee produced larger flexor muscle force than braced knee. Braced knee generated the largest extensor muscle force at early swing phase. In summary, musculoskeletal modelling simulation can be a computational tool to map and detect the differences between normal and asymmetrical gaits.

Impact of instrumental analysis of stiff knee gait on treatment appropriateness and associated costs in stroke patients

BACKGROUND

Stiff Knee Gait (SKG) in stroke patients is typically treated by the inhibition of the rectus femoris (RF) with botulinum toxin (BoNT) after clinical evaluation, obtaining an average pooled recovery in knee flexion (KF) of 7 degrees.

PURPOSE

Our hypothesis is that this limited recovery after BoNT could depend on the inadequacy in the selection of patients to be treated. The aim of this study was to assess the percentage of inappropriate treatments (PIT) that can be avoided when instrumental gait analysis (GA) is used, and to estimate the associated cost savings.

METHODS

We retrospectively analyzed GA data from chronic stroke patients with SKG and clinically assessed knee extensors spasticity referred to our laboratory over a five-year period. Gait kinematics and dynamic electromyography data were used. Patients were considered unsuitable for RF inhibition when: their SKG was determined by inadequate ankle push-off (APO) rather than by a brake from knee extensors, based on a previously published algorithm using gait kinematics (PIT_KIN); when RF was not active during KF (PIT_EMG); and when a proximal braking mechanism was found, if this was not due to RF activity (PIT_GA).

RESULTS

160 patients, age 20-87 years, gait speed 9-77%height/s, KF peak -4-44 degrees, were included. Of these, in 119 cases poor APO was the main cause of SKG, thus leading to PIT_KIN = 74%. In 48 out of 107 non-obese subjects, RF spasticity was not involved in SKG, resulting in PIT_EMG = 45%. Finally, patients with a braking activity as the main cause and concurrent RF activity were 20/107 = 19%, resulting in PIT_GA = 81% SIGNIFICANCE: When treating SKG, proper use of GA can reduce the percentage of inappropriate treatments by BoNT at the RF up to 81%. Savings are in the order of €100k/year when considering centers treating 100 or more patients/year.

Performance of stair negotiation in patients with cerebral palsy and stiff knee gait

BACKGROUND

Due to the limited knee range of motion, achieving adequate foot clearance while walking on level ground constitutes a major problem for patients with cerebral palsy and stiff knee gait. Stair negotiation as an activity of daily life requires a considerably higher knee range of motion than level ground walking, but little is known yet as to whether such patients are able to walk stairs.

RESEARCH QUESTION

The aim of this study was to investigate how patients with a limited knee range of motion negotiate stairs. Do they increase their peak knee flexion and use the same pattern as in walking on level ground? How do the muscles act during stair negotiation?

METHODS

In this explorative study, 17 adults with bilateral, spastic cerebral palsy and stiff knee gait and 25 healthy subjects were examined. 3D motion analysis, including electromyography, was performed while walking on level ground, upstairs, and downstairs. A linear mixed model was used for between- and within-group comparisons.

RESULTS

Walking upstairs and downstairs, patients increased their peak knee flexion by around 30° compared to level walking. Thus, increased knee flexion may be seen as the main mechanism for maintaining foot clearance on stairs. An increased pelvic obliquity (elevation) and hip flexion were also found and involved subjects showed a slight increase in rectus femoris activity when walking on stairs compared to level walking within the phases of high knee flexion.

SIGNIFICANCE

This study showed that patients with cerebral palsy and stiff knee gait are able to flex their knees more than would be required for level walking. Hence, the patients are able to adapt their rectus activity to stair walking to some extent. Therefore, further investigations might help to open up new therapeutic options to facilitate level walking and stair negotiation in patients with stiff knee gait.

Gait pathology subtypes are not associated with self-reported fall frequency in children with cerebral palsy

BACKGROUND

Trips and falls are common concerns reported by parents of children with cerebral palsy. Specific gait pathologies (excessive internal hip rotation, intoeing, and stiff knee gait) are anecdotally associated with higher rates of falls.

RESEARCH QUESTION

Is fall frequency higher for the aforementioned gait pathologies?

METHODS

Parent-reported fall frequency from 1063 children with cerebral palsy who also had a three-dimensional gait analysis was retrospectively reviewed. Frequency of 10 common gait pathologies was determined and fall frequency for the gait pathologies of interest were compared to matched control groups. Possible effects of Gross Motor Functional Classification System (GMFCS) level and age on fall frequency were also assessed and matched in the control group, as appropriate.

RESULTS

In general, parent-reported fall frequency increased from GMFCS level I to II and then decreased until level IV. Moreover, younger children tended to report greater fall frequency, though children who reported never falling were of similar age as those who reported weekly falls, resulting in an inverted-U shaped relationship. Children with cerebral palsy who walked with excessive internal hip rotation, excessive intoeing, or stiff knee gait did not report increased fall frequencies compared to other children with cerebral palsy matched on GMFCS level and age that did not walk with those gait patterns. Approximately 35% of children reported never falling, 35% reported falling daily, and 30% reported falling monthly or weekly for each gait pattern. Therefore, elevated fall frequency appears to be a generic problem for most children with CP rather than a function of a specific gait pattern.

SIGNIFICANCE

Clinicians should be aware of these relationships, or lack thereof, when trying to decipher the cause of a child's falling and when determining appropriate interventions. Future studies may seek to more objectively quantify fall frequency, as self-report is the main limitation of this study.

The functional effect of a distal rectus femoris tenotomy in adults with cerebral palsy

The purpose of this study was to determine the effect of a distal rectus femoris tenotomy on function and gait in adults with cerebral palsy who had diminished knee flexion during swing. A stiff knee gait pattern is commonly seen in individuals with cerebral palsy and frequently leads to tripping and falling. Five subjects, 25-51 years, (34.6±10.3 years) participated in the study; each individual had the surgery after the age of 18. Four of the five subjects underwent bilateral distal rectus femoris tenotomies for a total of nine limbs being studied. Four of the five subjects had a single procedure of a distal rectus femoris tenotomy and one subject also had bilateral adductor tenotomies. All individuals underwent a pre-operative and post-operative, (3.28±1.6 years) three-dimensional gait analysis. Pre-operative gait revealed diminished peak knee flexion and out of phase rectus femoris activity with a quiet vastus lateralis during swing in all subjects. Significant findings after a distal rectus femoris tenotomy included: improved peak swing knee flexion, improved peak stance hip extension, and increased total knee excursion without loss in knee extension strength. During swing, knee flexion angle improved on average 11° which correlated with subjective report of less shoe wear, tripping, and falling due to improved clearance. In conclusion, a distal rectus femoris tenotomy should be considered a surgical option for adults with cerebral palsy and a stiff knee gait pattern to improve mobility, function, and quality of life.

Rectus femoris transfer in cerebral palsy patients with stiff knee gait

BACKGROUND

Although several studies have reported on the outcomes of rectus femoris transfer (RFT), few have investigated the multiple factors that could affect the results. Therefore, we evaluated the outcomes of RFT and analyzed factors that influence improvement and annual change in knee motion after surgery in patients with cerebral palsy (CP).

METHODS

We reviewed ambulatory patients with CP who were followed up after they had undergone RFT as part of a single-event multilevel surgery (SEMLS) and who had undergone preoperative and postoperative three-dimensional (3D) gait analysis between January 1995 and December 2012. Relevant kinematic values, including peak knee flexion, knee range of motion, and timing of peak knee flexion in the swing phase and gait deviation index (GDI) score, were the outcome measures. Improvements in rate of angle and GDI score were adjusted by multiple factors such as sex, Gross Motor Function Classification System (GMFCS) level, anatomic type of CP, and concomitant surgeries as the fixed effects, and follow-up duration, laterality, and each subject as the random effects, all of which was performed using a linear mixed model.

RESULTS

A total of 290 patients (487 limbs) and 612 3D gait analysis (2-4 per patient) results were finally included in this study. At 2 years after RFT, estimated mean peak knee flexion (1.2°, p=0.005), estimated mean knee range of motion (10.7°, p<0.001), and estimated mean GDI score (7.3, p<0.001) increased significantly. Peak knee flexion in the swing phase occurred 5.4% earlier after surgery compared with that at baseline (p<0.001). In serial postoperative gait analyses, peak knee flexion in the swing phase occurred 0.8% earlier per year in patients with GMFCS level I or II (p=0.021).

CONCLUSIONS

RFT as part of a SEMLS was effective in treating stiff knee gait. In serial postoperative gait analyses, patients with GMFCS level I or II showed better prognosis than those with level III with regard to timing of peak knee flexion in the swing phase.

LEVEL OF EVIDENCE

Prognostic level IV.

A method to differentiate the causes of stiff-knee gait in stroke patients

Stiff-knee gait (SKG) is a common abnormal gait pattern in patients after stroke characterized by insufficient knee flexion (KF) during swing. Overactivity of the rectus femoris (RF) is considered the primary cause of SKG. Inadequate push-off has been indicated as an additional cause in the recent literature, as KF depends on knee flexion velocity in preswing (KFV). We used the peak of vertical acceleration of the malleolus (PMVA) as a kinematic-based indirect measure of push-off and studied its relationship with KF and KFV in a sample of 20 healthy subjects walking fast (v = 95 ± 5%heights(-1)), at self-selected speed (v = 74 ± 5%heights(-1)), slow (v = 54 ± 6%heights(-1)) and very slow (v = 38 ± 5%heights(-1)) and in a sample of 52 stroke patients with SKG (age 60 ± 11, v = 20 ± 11%heights(-1)). In healthy subjects PMVA occurred before knee flexion acceleration (p<0.001) and hip flexion acceleration (p<0.001). KF appeared as a bottom-up mechanism driven by the ankle push-off. From a regression analysis, the PMVA-KFV cause-effect relationship resulted strictly linear, with R(2) = 0.967, KFV = 0+7.1×PMVA, P<0.0001. Data from SKG patients were compared to this normal cause-effect model. For 44/52 patients the reduced KFV was combined with lack of push-off. Data from 8/52 patients only were statistically outside the 95%CI of the model, thus requiring for a braking mechanism to explain KFV reduction. In stroke adults of our sample the push-off impairment (85% of cases) and not the inappropriate knee extension moment produced by the thigh muscles was the primary cause of SKG. This result could explain the low average efficacy (<10°) of focal and surgical treatments at the quadriceps. The presented model could be used to differentiate the primary cause of SKG between inadequate push-off and braking activity of the thigh muscles, thus increasing the effectiveness of the selected treatment.