Adult Spastic Cerebral Palsy: A Case Study with Anterior Knee Pain

Original Editor - Tessah MacDowall

Top Contributors - Larry Burcher, Meagan Milton, Mackenzie Peters, Gillian Plummer, Erynne Rowe

Abstract

The purpose of this fictional case study is to outline the out-patient management of a 38-year-old female with CP whose primary complaint is of bilateral anterior knee pain. Early on in her CP diagnosis, she was given a level II rank on the Gross Motor Function Classification System (GMFCS) indicating that she can ambulate but has difficulties with uneven surfaces. Upon objective assessment, it was found that she has some indications of spasticity within the hamstrings and quadriceps according to the Modified Ashworth Scale. She also demonstrated a crouch gait pattern and reduced strength bilaterally in hip extensors, knee extensors, and ankle plantar flexors. Since quality of life has been shown to increase following improvements in walking, the focus of the program implemented in this case study is on gait training. Taken together, the information outlined in this fictional case can provide some evidence to guide decision-makers in the future and to highlight the importance of further research in adults that have CP.  

Introduction

Cerebral palsy (CP) is an umbrella term used to describe a group of non-progressive motor impairment disorders (Amankwah et al., 2020; van Gorp et al., 2020). It is the result of neurodevelopmental disturbances, such as premature birth or stroke, that occurred at any time from conception to when the child was two years of age (Amankwah et al., 2020; Physiopedia, 2022). It is one of the most common causes of motor disability in children, with approximately 2 to 2.5 in 1000 Canadian children meeting the criteria for diagnosis (Amankwah et al., 2020; Physiopedia, 2022; van Gorp et al., 2020). The disease’s severity is classified using the Gross Motor Function Classification System (GMFCS)(Palisano et al., 2007; Physiopedia, 2022).  

Despite occurring in early childhood, approximately 75 percent of individuals currently living with CP are older than 18 years of age (van Gorp et al., 2020). This number is expected to significantly increase by 2031 (Amankwah et al., 2020). As individuals with CP age, the clinical presentation of the condition changes. Adults with CP are roughly 7 to 10 times more likely than the general population to have a musculoskeletal morbidity (French et al., 2019; Whitney et al., 2018; van Gorp et al., 2020). Furthermore, nearly one-third of adults with CP report musculoskeletal pain that is associated with deteriorating physical function, such as inability to ambulate, and reduced participation in daily life (Booth et al., 2018; Ganjwala & Shah, 2019; O’Connell et al., 2019; Rethlefsen et al., 2015).  

Musculoskeletal impairments and pain may be caused by altered gait patterns (Ganjwala & Shah, 2019; Miller, 2020; Rethlefsen et al., 2015). Specifically, the crouch (i.e., knee flexion) gait pattern commonly seen in individuals with CP has been significantly associated with knee pain (Ganjwala & Shah, 2019; Rethlefsen et al., 2015). Crouch gait is used to describe the two common knee patterns seen in CP gait: (1) increased knee flexion during the stance phase and (2) reduced knee flexion during the swing phase (Ganjwala & Shah, 2019). Increased knee flexion during stance may be caused by hamstring spasticity, quadriceps weakness, soleus weakness, and/or lever-arm dysfunction, whereas decreased knee flexion during swing may be due to rectus spasticity (Ganjwala & Shah, 2019). As a result of the crouch gait pattern, there is also an increase in patellofemoral forces in individuals with CP (Pelrine et al., 2020; Rethlefsen et al., 2015). Furthermore, in a CP patient population, the patella is often located proximally to its typical anatomical location (i.e., patella alta) and is therefore more susceptible to dysfunction or subluxation that contributes to knee pain (Miller, 2020). Improvements in independence, participation in activities of daily living, and overall quality of life can be seen following improvements in gait patterns (Booth et al., 2018).  

Client Characteristics

The patient is a 38-year-old female diagnosed with bilateral spastic CP. She was diagnosed at the age of 5 due to observable mild developmental delays, abnormal posture and high muscle tone. It was later discovered that she fell into the Level II category of the GMFCS (Palisano et al., 2007). The patient reports that their forearm crutches are used during ambulation and provide increased stability and support. The patient presents with several health complications including type II diabetes, epilepsy, obesity (BMI of 32), chronic pain, and fatigue. The patient is seeking outpatient physiotherapy care for her bilateral anterior knee pain as a result of spasticity and altered gait (Yi et al., 2019). The patient explains that the pain has progressively gotten worse over the last three months, rating it 7/10 on the numeric pain rating scale when walking and reports that it takes over an hour for her pain to come down to 3/10 when resting. The patient lives in a single -level community home where she has her own bedroom and bathroom. She reports being independent in most activities of daily living (ADLs) but relies on the support personnel for her meals and medication.  

Discussion

This fictional case followed a 38-year-old female, who presented to physiotherapy with bilateral anterior knee pain secondary to her diagnosis of spastic CP, through 12 weeks of treatment. Upon arrival, she mentioned that her knee pain was worsening and had limited her participation in many of her hobbies (ie., swimming). An objective assessment found indications of spasticity within the hamstrings and quadriceps and reduced strength bilaterally in hip extensors, knee extensors, and ankle plantar flexors contributing to a crouch gait pattern. As anterior knee pain can result from all of  these findings, our treatment intervention focused on targeting these issues. Prior to discharge, after 12 weeks, the patient displayed marked improvements in gait, walking endurance, lower extremity strength and pain. At the time of discharge, she was starting to increase her participation in hobbies that she previously had issues with and met all her outpatient physiotherapy goals. She was encouraged to continue working on strengthening her hip extensors, knee extensors, and ankle plantar flexors.  

In general, the interventions described throughout this fictional case would be applicable to other patients with similar conditions. First, the characteristics of this fictional case are similar to the typical presentation of CP. Specifically, 80 to 90 percent of individuals with CP have spastic CP (Physiopedia, 2022) and approximately 21 percent of individuals with CP experience anterior knee pain (Rethlefsen et al., 2015). It is important to note that the chance of knee pain also increases significantly (73.2 percent) with the presence of patella alta (Pelrine et al., 2020). It is therefore more likely that an individual with CP, who is coming to physiotherapy, will display one or multiple characteristics that are similar to this fictional case.  

Secondly, despite representing 75 percent of all individuals living with CP, there is limited research surrounding its management in an adult population. This means that there are no validated outcome measures for this population making it difficult to objectively determine whether your patient is making progress or not. The current case study uses evidence-based literature to provide potential options, such as the TUG or 6MWT, to mitigate this issue. While the TUG and 6MWT are not specific to the CP population, they do provide meaningful information about the patient’s locomotor function and walking endurance. For example, previous research has found that it is possible to increase the speed that a child with crouch gait walks by 30 percent if you increase the amount of knee extension during the stance phase (Cherni et al., 2019). Since the interventions of this case study targeted increasing knee extension, measuring gait speed using the TUG or 6MWT, where a shorter time indicates a faster pace, will provide the physical therapist with an objective outcome measure.

In conclusion, research in management of CP in adults is limited. This fictional case used available literature to devise a treatment plan to resolve bilateral anterior knee pain, in an adult patient with CP, that would target the objective findings of spasticity and weakness of the lower extremities and an altered gait pattern.