Background
Cerebral palsy (CP) is the most common cause of physical disability in childhood with an incidence of 2.11 per 1000 live births [
1]. It describes a “group of permanent disorders of the development of movement and posture, causing activity limitations that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain” [
2]. In 2013, the Australian Cerebral Palsy Register reported that 71% of children with CP achieved ambulation and 91% were classified with spasticity as the predominant motor type. Children with lower limb spasticity often experience a range of impairments including weakness, tightness, reduced motor control and muscle selectivity. These impairments can lead to limitations in functional ability, balance, ambulation and fitness compared to typically developing peers [
3,
4]. Physiotherapy intervention focuses on reducing these impairments and optimising functional, goal-related performance.
Focal, intramuscular Botulinum Toxin-Type A (BoNT-A) injections to the lower limb are commonly used in combination with physiotherapy as the temporary reduction in spasticity provides an opportunity to facilitate rehabilitation outcomes [
5‐
8]. For ambulant children with CP (Gross Motor Functional Classification System, GMFCS-E&R, Levels I-III [
9]), there is strong evidence that injections of BoNT-A are safe and reduce muscle tone in spastic, active and non-fibrotic lower limb muscles for approximately 12–16 weeks [
6,
7,
10‐
12]. BoNT-A impacts body structure and function, however the accompanying physiotherapy often targets activity level outcomes (International Classification of Functioning, Disability and Health, ICF [
13]).
Functional improvement in ambulant children with CP has been reported in a number of randomised controlled trials (RCTs) comparing intramuscular lower limb BoNT-A injections with rehabilitation (physiotherapy, casting and/or orthotic management), to a control group of rehabilitation alone with or without placebo injections. Rehabilitation combined with BoNT-A injections demonstrated significantly greater improvement in gross motor function as measured by the Gross Motor Function Measure (GMFM-88 or-66) [
14‐
18] and quality of gait using the Physician’s Rating Scale [
14,
19‐
22], Edinburgh Visual Gait Score (EVGS) [
23] or Three Dimensional Gait Analysis (3DGA) [
20]. Improvement in performance-related goals have been reported when measured by the Canadian Occupational Performance Measure (COPM) [
17], Goal Attainment Scaling (GAS) [
24] or parental questionnaires [
15,
16,
25].
Despite the acknowledged success of physiotherapy rehabilitation combined with BoNT-A injections, relative effectiveness of the specific components of physiotherapy rehabilitation, including intensity and dose, is difficult to interpret because it is often poorly described [
14,
15,
17,
25]. Results of a number of systematic reviews and consensus papers found limited evidence to support or refute individual physiotherapy modalities post lower limb BoNT-A injections [
5,
7,
11,
26]. The content of physiotherapy rehabilitation outlined in reported studies has included: active and passive stretching of muscle agonists [
16,
18,
22,
23,
27]; functional or resistive strengthening of the antagonists [
16,
18,
22,
23,
27]; functional mobility training and/or gait training [
16,
18,
23,
27]. One retrospective, controlled intervention study has directly compared the specific content of two physiotherapy approaches following lower limb BoNT-A injections [
28]. Thirty-eight children with CP (mean age 7 years, 7 months, GMFCS I-III, 11 unilateral, 27 bilateral motor distribution) who received Neurodevelopmental Treatment (NDT, mean total dose 24.2 hours) were randomly selected and retrospectively matched to a group of children who received conventional physiotherapy (CPT, mean total dose 20.5 hours). Content of physiotherapy, determined via therapist questionnaires, and improvement of impairment and gait-related goals (GAS) were compared between groups two months post injection. Both approaches utilized muscle tone inhibition techniques, stretching, strengthening and functional training, with the NDT group spending a greater proportion of time on functional training (NDT 42%; CPT 28%,
p = 0.009). Whilst the NDT group showed greater goal attainment post intervention (mean converted GAS score NDT 56, CPT 52,
p = 0.008), results should be interpreted cautiously. Therapy content was only described and analysed for 62% (n = 47) of children due to reduced completion of questionnaires by treating physiotherapists. As GAS goals were impairment-based it is unclear from this study if a more functional approach to training translates to improvement in goals related to function and participation.
In the absence of high level evidence, expert opinion and consensus statements recommend post BoNT-A physiotherapy includes functional and targeted motor training in combination with serial casting, stretching and strengthening [
7,
8,
29]. Additionally, intervention should incorporate: (1) collaborative, individualized, realistic and specific goal setting which span across all domains of the ICF [
7,
29]; (2) specificity of task and training [
30,
31]; (3) repetition and practise within a functional “just right” context [
32,
33]; (4) environmental adaption [
34] and (5) strategies to increase motivation and engagement [
35,
36]. This approach will facilitate rehabilitation focused on each child’s specific goals and functional needs [
6,
33,
37]. Studies investigating the efficacy of physiotherapy combined with BoNT-A injections have consistently included therapy delivered in an individual model. It is unclear whether similar outcomes could be achieved using alternative methods of physiotherapy delivery.
Four models of therapy delivery have been reported in the literature for children with CP including: (1) individual (one on one); (2) group-based (three or more participants with similar abilities [
38]); (3) web-based training or virtual reality [
39,
40]; (4) individual consultation with intervention performed as a home programme [
41]. Group-based training has been shown to achieve positive rehabilitation outcomes through maximising engagement, motivation and participation [
36,
42]. Relative effectiveness of group versus individual physiotherapy post lower limb BoNT-A injections has not been examined to date, however. Independent of BoNT-A, effectiveness of group versus standard individualised care has been compared for ambulant children with CP receiving strength, endurance and fitness training [
43,
44], progressive functional strength training [
45,
46] and goal-directed activity-focused physiotherapy [
47]. Results are difficult to compare due to the heterogeneity of theoretical focus, therapy dose and outcome measures used. However, these studies provide useful guidelines for the elements that contribute to successful group-based physiotherapy.
Effective group-based physiotherapy interventions report similar session structure including warm up, specific intervention activities and then warm down. To maintain motivation and specificity of practise, a combination of group-based activity and individual or paired circuit activity has been recommended [
43,
44,
46,
47]. To ensure adequate supervision and progression of exercises, group sizes have been limited to small (4–6 children) [
44,
45,
47] or medium (7–9 children) [
43]. Effective dose is not well understood due to variability in intensity, frequency and duration of intervention. Total direct therapy dose has varied from 36 hours [
43,
45] to 70 hours [
44], delivered in varying intensity from three week blocks (intensive model) [
47] to 34.6 weeks (distributed model) [
44]. Individual session duration has ranged from 45 to 180 minutes with a frequency of two to five sessions per week. Indirect treatment dose achieved via home programme is difficult to interpret due to inadequate reporting. Despite insufficient evidence to confirm optimal group format, several studies found that group-based therapy can achieve equal or greater improvement in outcomes across ICF domains when compared to individual standard care. These include improvements in gross motor ability (GMFM-66) [
43,
44,
47], crouch gait (3DGA) [
48], participation (Children’s Assessment of Participation and Enjoyment: CAPE) [
44], health-related quality of life (TACQOL) [
44] and goal attainment (GAS) [
47]. One RCT (n = 51) compared group-based progressive resistance exercise strength training to individualised standard care in 51 ambulant children with CP (GMFCS I-III; mean age 10y 5mo, SD 1y 10mo; 29 male) [
45,
46]. This study reported no improvement in either group for gross motor ability (GMFM-66), walking ability (One Minute Fast Walk Test) or participation (CAPE). No studies have reported inferior outcomes for group-based interventions compared to individual standard care. Additional qualitative benefits of a group-based model have been reported in the context of the self-determination theory [
49,
50]. A group program may enhance self-regulation and engagement in the therapy process by attending to children’s basic psychological needs for Autonomy, Relatedness and Competence. There is potential for greater promotion of autonomy by allowing choice (personal goal setting), and through enjoyment, having fun and behaviour modelling to master activities [
36,
51]. A sense of competence may be fulfilled through scaffolding activities to promote skill development, and providing opportunities for peer learning [
52‐
54] and healthy competition [
30,
36]. Social support and working with children with similar needs may also increase the feeling of relatedness [
36,
55].
A group model has the potential to meet the physiotherapy rehabilitation needs for children post lower limb BoNT-A injections. To date there has been no study that has directly compared dose and content-matched group versus individual models of functional, goal-directed physiotherapy rehabilitation following lower limb BoNT-A injections for ambulant children with CP. This study aims to compare the efficacy of these two models to enable informed choice of post BoNT-A physiotherapy rehabilitation delivery.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
RT, MK and LJ were responsible for the study concept, design and ethics applications. LS provided statistical advice for the study design. MK and LJ obtained funding for development of the study protocol and ethics submission. MK obtained funding for the study. RT registered the trial with ACTRN and drafted the manuscript which was critically reviewed by all authors. All authors read and approved the final manuscript.