Does Orthopedic Surgery Improve Gait Efficiency in Children With Cerebral Palsy? A Retrospective Study (OrthoSurg01)

Purpose: The aim of this retrospective observational study is to describe the demographic, clinical, and functional characteristics of children and adolescents with spastic cerebral palsy (CP) undergoing Single Event Multilevel Surgery (SEMLS) and changes in their gait efficiency following surgery.

Methods: Seventy-eight participants were included and a total of eighty-four SEMLS analyzed. All the participants were followed by the Children Rehabilitation Unit of the Local Health Authority of Reggio Emilia. Participants met the following requirements: age 4-20 years; hemiplegic or diplegic CP; Gross Motor Function Classification System level I, II or III; 3D gait analysis either before and after surgery. The following parameters were reported: maximum hip and knee extension in the gait cycle, to measure the gait efficiency; normalized maximum power produced by the ankle during push-off phase, to express the propulsive capacity; normalized speed and normalized stride length as global gait performance measure.

Study Overview

• Status: Completed
• Conditions: Cerebral Palsy (CP)
• Intervention / Treatment: Procedure: single-event multilevel surgery

Detailed Description

Children with Cerebral Palsy (CP) often have gait difficulties due to poor motor control, spasticity, skeletal deformities, and muscle weakness. Their walking is usually slow, tiring, with reduced endurance, and a higher risk of falls. As a result, these children often have limited participation in daily activities and a lower quality of life. Among the most common treatments, functional orthopedic surgery is now considered the "standard of care" for these patients. Many studies have shown that surgery has a positive impact on walking ability.

In the traditional surgical approach, patients undergo multiple operations, each correcting a single issue. For example, fixing a shortened triceps muscle, to allow the foot to fully contact the ground, might be followed by lengthening the knee flexors to enable full knee extension and upright standing. This step-by-step process, where surgeries are often done annually, was called the "birthday syndrome". Some researchers have studied the effects of surgery on specific walking issues. For example, in 2022, Kruger K.R. et al. examined the long-term impact of correcting valgus-pronated feet. Dohin B. et al., in 2020, looked at how lengthening knee flexors and adductors improved in-toeing gait. Krupiński M. et al., in 2015, studied the effect of Achilles tendon lengthening in children with toe-walking (equinus gait). While these studies provided useful insights for clinicians, they often oversimplified the complexity of the underlying problems.

In CP, multiple areas of the body are usually involved in walking difficulties, as seen in crouch gait (walking with bent knees), which can have many causes that influence each other. This often requires surgery on multiple areas at once to improve the overall balance of the body. More recently, surgeons have adopted a technique where multiple deformities are corrected in a single surgery, often involving both lower limbs. This approach, known as single-event multilevel surgery (SEMLS), reduces the number of surgeries compared to the traditional method of addressing one issue at a time. However, as children grow, additional SEMLS procedures may be needed to address new issues that arise, such as muscle tightness. Several studies have shown that these multilevel surgeries can improve walking ability. Saglam Y. et al., in 2016, studied the combination of femoral derotational osteotomy and soft tissue procedures in children with in-toeing gait. In 2022, Pierz K. et al. examined how SEMLS, including knee flexor lengthening combined with other techniques (such as triceps lengthening or tibial derotational osteotomy), improved walking in children with crouch gait. Moreira de Freitas Guardini K. et al., in 2021, also studied a large sample of children undergoing SEMLS, focusing on their clinical characteristics.

Evaluating the effects of surgery requires selecting appropriate outcome measures, which is not always simple. Most studies aim to improve "gait quality" but do not always confirm if the chosen parameters lead to real functional improvements for the patient. Some researchers use measures from physical exams (e.g., range of motion, muscle strength) or biomechanical data from gait analysis (3DGA, the gold standard for assessing gait in children with CP). These studies often focus on how the body moves (kinematics) and on spatiotemporal parameters such as walking speed and step length, along with summary indices. These parameters show changes in the specific area operated on and how the body moves as a whole. They provide information on alignment and symmetry of the legs during movement.

However, a well-aligned structure does not necessarily involve that the system works efficiently, meaning it minimizes energy expenditure during walking. Gait efficiency is especially important in children with CP, as many studies have shown that inefficient gait leads to increased energy consumption and mechanical work. Therefore, it is important to consider not only joint movement and overall performance but also other aspects, since kinematic data and physical exams do not provide information on gait efficiency.

Marconi V. et al. (2014) conducted a prospective study on energy consumption and mechanical work in children with CP after SEMLS. Their study showed a reduction in energy consumption after surgery, but the small sample size (10 children) and mixed group of patients (including hemiplegic, diplegic, and quadriplegic children) limit the generalizability of the results. Marconi V. et al. used the energy calculation method proposed by Willems P.A. et al. (1995), while Van de Walle P. et al. (2012) suggested that joint power calculations might be more valid and sensitive for CP. Other researchers have used indirect measures of efficiency, finding correlations between energy consumption and variables like pelvic vertical oscillation (assessed by the BEQ index, Kerrigan D.C. et al. 1996) or maximum knee and hip extension (Noorkoiv M. et al, 2019). These measures have been used to assess gait efficiency in CP, but not specifically to evaluate the effects of surgery.

The aim of this retrospective observational study is to describe the functional characteristics of children and adolescents with spastic cerebral palsy (CP) undergoing SEMLS and changes in their gait efficiency following surgery.

Methods:

This is a retrospective monocentric observational study. Outcome measures were collected before surgery (T0) and after surgery (T1) in a time span between 8 and 38 months. The surgical recommendation was tailored to the participants' requirements and decided through a comprehensive assessment, which included a standardized physical exam, radiographic studies, and instrumental gait analysis.

Gait analysis was performed by means of a Vicon® system (Oxford Metrics Group, Oxford, UK). The system was equipped with eight optoelectronic cameras, two force plates (AMTI, USA), and two video cameras. All assessments were conducted in the Motion Analysis Laboratory LAMBDA, Azienda USL-IRCCS di Reggio Emilia. The same assessor evaluated all participants.

Age and the level of Gross Motor Function Classification System (GMFCS) were collected before surgery.

The analyses will be conducted by the Statistics and Clinical Studies Office of the USL IRCCS in Reggio Emilia using SAS System, R, or SPSS software, depending on availability at the time. Quantitative and qualitative data will be analyzed and presented using mean, standard deviation (SD), median, interquartile range (IQR), and relative frequencies. Central tendency measures and percentages will be accompanied by 95% confidence intervals (CI). Normality of quantitative data will be assessed with the Shapiro-Wilk test. Appropriate statistical tests will be applied to compare measures between the two time points, T0 and T1.

To assess gait efficiency, the mean maximum extension values will be compared between T0 and T1 in the SEMLS surgery group using the paired Student's t-test or Wilcoxon test, depending on the normality assumption. Without aiming for comparison, the same measurements will also be described for the non-surgical group to observe trends.

For quantitative variable comparisons between the two time points, the paired Student's t-test or Wilcoxon test will be applied based on normality.

• Study Type: Observational
• Enrollment (Actual): 78

Contacts and Locations

Study Locations

• Italy
  • Reggio Emilia, Italy
    • Azienda Unità Sanitaria Locale Reggio Emilia
  • Reggio Emilia, Italy, 42122
    • AziendaUSL IRCCS Reggio Emilia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population will include patients who attended the Children Rehabilitation Unit of Local Health Authority of Reggio Emilia from 2011 to 2021. The study will focus on patients diagnosed with cerebral palsy who underwent lower limb SEMLS (single-event multilevel surgery) and 3D Gait Analysis before and after surgery.

Description

Inclusion Criteria:

• diagnosis of diplegic or hemiplegic CP;
• GMFCS levels I, II, or III;
• aged between 4 and 20 years;
• Lower limb Single Event Multilevel Surgery (SEMLS)
• 3D gait analysis before and after surgery

Exclusion Criteria:

• more than one lower limb surgery event between the two gait assessments
• one single gait evaluation

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
SEMLS group; The study population will include patients who attended the Children Rehabilitation Unit of Local Health Authority of Reggio Emilia from 2011 to 2021. The study will focus on patients diagnosed with cerebral palsy who underwent lower limb SEMLS (single-event multilevel surgery) and 3D Gait Analysis before and after surgery.	Procedure: single-event multilevel surgery; surgical orthopedic approach where multiple deformities are corrected in one solution, often involving both lower limbs, to improve walking performance

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean maximum knee extension in the gait cycle	It is an indirect measure of walking efficiency. Greater knee extension leads to lower energy consumption. The measurement is calculated using 3D Gait Analysis. It has already been used to assess gait efficiency in children with CP (Noorkoiv, 2019), but never to evaluate the effects of surgery. These measures are useful when dynamic data are not available, such as when the stride length is short or the patient has low endurance, making it difficult to collect such data	T0 (before SEML) and T1 (8-38 months after SEMLS)
change from baseline in maximum knee extension	It is an indirect measure of walking efficiency. Greater knee extension leads to lower energy consumption. The measurement is calculated using 3D Gait Analysis. It has already been used to assess gait efficiency in children with CP (Noorkoiv, 2019), but never to evaluate the effects of surgery. These measures are useful when dynamic data are not available, such as when the stride length is short or the patient has low endurance, making it difficult to collect such data.	T0 (before SEML) and T1 (8-38 months after SEMLS)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation between the effect of surgery and the level of impairment	Pearson's correlation will assess the relationship between age and surgical effect, measured as the difference in maximum knee extension. Additional correlation measures will be calculated to evaluate the relationship between surgical effect and the degree of impairment in patients.	at T1( 8-38 months after SEMLS )
Correlation between the effect of surgery and the age of participants	Pearson's correlation will assess the relationship between age and surgical effect, measured as the difference in maximum knee extension. Additional correlation measures will be calculated to evaluate the relationship between surgical effect and the degree of impairment in patients	at T1( 8-38 months after SEMLS )
change from baseline in maximum hip extension	It is an indirect measure of walking efficiency. Greater knee extension leads to lower energy consumption. The measurement is calculated using 3D Gait Analysis. It has already been used to assess gait efficiency in children with CP (Noorkoiv, 2019), but never to evaluate the effects of surgery. These measures are useful when dynamic data are not available, such as when the stride length is short or the patient has low endurance, making it difficult to collect such data.	T0 (before SEML) and T1 (8-38 months after SEMLS)
change from baseline in power produced by the ankle during push-off phase	This parameter was chosen to assess efficiency because research shows that having adequate push-off strength is important for efficient walking (Jonkers et al., 2009). Keeping good propulsion ability after surgery is therefore a priority. Some authors have noted the risk of over-correction (Dietz et al., 2006; Sclavor et al., 2022), which can lead to iatrogenic weakness in the triceps and reduced walking efficiency (J. Lorentzen et al., 2020).	at T1( 8-38 months after SEMLS )
change from baseline in energy produced and absorbed	This parameter was chosen to assess efficiency because research shows that having adequate push-off strength is important for efficient walking (Jonkers et al., 2009). Keeping good propulsion ability after surgery is therefore a priority. Some authors have noted the risk of over-correction (Dietz et al., 2006; Sclavor et al., 2022), which can lead to iatrogenic weakness in the triceps and reduced walking efficiency (J. Lorentzen et al., 2020).	T0 (before SEML) and T1 (8-38 months after SEMLS)
Change from baseline in Biomechanical Efficiency Quotient (BEQ)	To evaluate walking efficiency, the Biomechanical Efficiency Quotient (BEQ) (Kerrigan et al., 1996) was also included, obtained from three parameters: average step length, vertical displacement of the trunk during walking and height of the sacrum during standing. Kerrigan et al., show that this summary index is useful for evaluating the impact of physical therapy interventions, such as the use of Ankle Foot Orthosis (AFO), on biomechanical efficiency. From reviewing the literature, it appears that this measure has never been used to assess the effect of surgery.	T0 (before SEML) and T1 (8-38 months after SEMLS)
Change from baseline in Gait Profile Score (GPS)	As a measure to evaluate gait quality, the Gait Profile Score (GPS) (Baker et al., 2009) was chosen. It is a general index that summarizes the overall deviation of kinematic gait data from reference data (Moreira de Freitas Guardini K. et al., 2021). The GPS can be broken down into the Gait Variable Score (GVS), which is based on nine kinematic variables: pelvic tilt, pelvic rotation, pelvic obliquity, hip and knee flexion/extension, ankle dorsiflexion/plantarflexion, hip abduction/adduction, hip rotation, and foot progression angle (Speciali DS et al., 2014). A decrease in the GPS score is considered an improvement. In the 2012 study, Baker et al. also defined the Minimal Clinical Important Difference (MCID), which is the smallest clinically relevant difference for this parameter. For the GPS, the MCID is 1.6°	T0 (before SEML) and T1 (8-38 months after SEMLS)
Change from baseline in speed, Stride length, ratio frequency/stride lenght, stance time and double support	The spatiotemporal kinematic parameters will be used to compare overall walking performance, as done by other authors like Pierz et al. in 2022.	T0 (before SEML) and T1 (8-38 months after SEMLS)

Collaborators and Investigators

• Sponsor: Azienda Unita Sanitaria Locale Reggio Emilia
• Investigators: Principal Investigator: Silvia Sassi, MD, Azienda USL IRCCS of Reggio Emilia

Publications and helpful links

General Publications

• Graham HK, Rosenbaum P, Paneth N, Dan B, Lin JP, Damiano DL, Becher JG, Gaebler-Spira D, Colver A, Reddihough DS, Crompton KE, Lieber RL. Cerebral palsy. Nat Rev Dis Primers. 2016 Jan 7;2:15082. doi: 10.1038/nrdp.2015.82.
• Palisano R, Rosenbaum P, Walter S, Russell D, Wood E, Galuppi B. Development and reliability of a system to classify gross motor function in children with cerebral palsy. Dev Med Child Neurol. 1997 Apr;39(4):214-23. doi: 10.1111/j.1469-8749.1997.tb07414.x.
• Visscher R, Hasler N, Freslier M, Singh NB, Taylor WR, Brunner R, Rutz E. Long-term follow-up after multilevel surgery in cerebral palsy. Arch Orthop Trauma Surg. 2022 Sep;142(9):2131-2138. doi: 10.1007/s00402-021-03797-0. Epub 2021 Feb 23.
• Vermuyten L, Desloovere K, Molenaers G, Van Campenhout A. Proximal femoral derotation osteotomy in children with CP : long term outcome and the role of age at time of surgery. Acta Orthop Belg. 2021 Mar;87(1):167-173.
• Van de Walle P, Hallemans A, Schwartz M, Truijen S, Gosselink R, Desloovere K. Mechanical energy estimation during walking: validity and sensitivity in typical gait and in children with cerebral palsy. Gait Posture. 2012 Feb;35(2):231-7. doi: 10.1016/j.gaitpost.2011.09.012. Epub 2011 Oct 2.
• van den Hecke A, Malghem C, Renders A, Detrembleur C, Palumbo S, Lejeune TM. Mechanical work, energetic cost, and gait efficiency in children with cerebral palsy. J Pediatr Orthop. 2007 Sep;27(6):643-7. doi: 10.1097/BPO.0b013e318093f4c3.
• Schwartz MH, Rozumalski A, Novacheck TF. Femoral derotational osteotomy: surgical indications and outcomes in children with cerebral palsy. Gait Posture. 2014 Feb;39(2):778-83. doi: 10.1016/j.gaitpost.2013.10.016. Epub 2013 Oct 27.
• Saglam Y, Ekin Akalan N, Temelli Y, Kuchimov S. Femoral derotation osteotomy with multi-level soft tissue procedures in children with cerebral palsy: Does it improve gait quality? J Child Orthop. 2016 Feb;10(1):41-8. doi: 10.1007/s11832-015-0706-4. Epub 2015 Nov 23.
• Ries AJ, Schwartz MH. Low gait efficiency is the primary reason for the increased metabolic demand during gait in children with cerebral palsy. Hum Mov Sci. 2018 Feb;57:426-433. doi: 10.1016/j.humov.2017.10.004. Epub 2017 Oct 21.
• Pierz K, Brimacombe M, Ounpuu S. Percutaneous hamstring lengthening in cerebral palsy: Technique and gait outcomes based on GMFCS level. Gait Posture. 2022 Jan;91:318-325. doi: 10.1016/j.gaitpost.2021.10.035. Epub 2021 Oct 29.
• Noorkoiv M, Lavelle G, Theis N, Korff T, Kilbride C, Baltzopoulos V, Shortland A, Levin W, Ryan JM. Predictors of Walking Efficiency in Children With Cerebral Palsy: Lower-Body Joint Angles, Moments, and Power. Phys Ther. 2019 Jun 1;99(6):711-720. doi: 10.1093/ptj/pzz041.
• de Freitas Guardini KM, Kawamura CM, Lopes JAF, Fujino MH, Blumetti FC, de Morais Filho MC. Factors related to better outcomes after single-event multilevel surgery (SEMLS) in patients with cerebral palsy. Gait Posture. 2021 May;86:260-265. doi: 10.1016/j.gaitpost.2021.03.032. Epub 2021 Mar 27.
• Moisan G, Bonnefoy-Mazure A, De Coulon G, Tabard-Fougere A, Armand S, Turcot K. Assessment of gait quality and efficiency after undergoing a single-event multilevel surgery in children with cerebral palsy presenting an intoeing gait pattern. Childs Nerv Syst. 2022 Aug;38(8):1523-1530. doi: 10.1007/s00381-022-05548-x. Epub 2022 May 12.
• Marconi V, Hachez H, Renders A, Docquier PL, Detrembleur C. Mechanical work and energy consumption in children with cerebral palsy after single-event multilevel surgery. Gait Posture. 2014 Sep;40(4):633-9. doi: 10.1016/j.gaitpost.2014.07.014. Epub 2014 Jul 24.
• Kruger KM, Constantino CS, Graf A, Flanagan A, Smith PA, Krzak JJ. What are the long-term outcomes of lateral column lengthening for pes planovalgus in cerebral palsy? J Clin Orthop Trauma. 2021 Nov 26;24:101717. doi: 10.1016/j.jcot.2021.101717. eCollection 2022 Jan.
• Kerrigan DC, Thirunarayan MA, Sheffler LR, Ribaudo TA, Corcoran PJ. A tool to assess biomechanical gait efficiency; a preliminary clinical study. Am J Phys Med Rehabil. 1996 Jan-Feb;75(1):3-8. doi: 10.1097/00002060-199601000-00003.
• Kadhim M, Miller F. Crouch gait changes after planovalgus foot deformity correction in ambulatory children with cerebral palsy. Gait Posture. 2014 Feb;39(2):793-8. doi: 10.1016/j.gaitpost.2013.10.020. Epub 2013 Nov 2.
• Almoajil H, Dawes H, Hopewell S, Toye F, Jenkinson C, Theologis T. Development of a core outcome set for lower limb orthopaedic surgical interventions in ambulant children and young people with cerebral palsy: a study protocol. BMJ Open. 2020 Mar 4;10(3):e034744. doi: 10.1136/bmjopen-2019-034744.
• Dohin B, Haddad E, Zagorda-Pallandre B, Zemour M. Outcomes of isolated soft tissue surgery for in-toeing gait in patients with ambulatory cerebral palsy. Orthop Traumatol Surg Res. 2020 Nov;106(7):1367-1371. doi: 10.1016/j.otsr.2020.06.008. Epub 2020 Sep 29.

Study record dates

Study Major Dates

• Study Start (Actual): February 20, 2024
• Primary Completion (Actual): September 12, 2024
• Study Completion (Actual): September 12, 2024

Study Registration Dates

• First Submitted: September 20, 2024
• First Submitted That Met QC Criteria: October 1, 2024
• First Posted (Actual): October 2, 2024

Study Record Updates

• Last Update Posted (Actual): October 2, 2024
• Last Update Submitted That Met QC Criteria: October 1, 2024
• Last Verified: October 1, 2024

More Information

Terms related to this study

• Keywords: Adolescent; Rehabilitation; Child; Cerebral palsy; Gait Analysis; Orthopedics; Physically Challenged
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neurologic Manifestations; Brain Damage, Chronic; Cerebral Palsy; Paralysis
• Other Study ID Numbers: 134/2023/OSS/AUSLRE

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: To protect participant privacy the IPD will not be shared, unless upon reasonable request.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No