Challenging Current Hip Reconstruction Practices in Patients with Cerebral Palsy

Abstract

In April 2006, an international working group revised Bax’s widely used modern definition of Cerebral Palsy (CP), characterizing it as: “A group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain. The motor disorders of CP are often accompanied by disturbances of sensation, perception, cognition, communication and behavior, by epilepsy, and by secondary musculoskeletal problems”. CP remains the most common cause of chronic childhood disability, with a prevalence of 2-2.5 per 1000 live births in developed countries. This thesis will address two intertwined and critical aspects of CP, aligned with its contemporary holistic definition. First, due to the non-progressive but permanent nature of the primary brain lesion in CP, many acquired clinical manifestations such as musculoskeletal pathology progress over time in the setting of growth and spasticity. Hip displacement, second only to Achilles contracture in prevalence, effects approximately 35% of all children with CP, and is positively correlated with the severity of functional impairment as defined by the Gross Motor Function Classification System (GMFCS). This is a five-level ordinal rating scale based on the assessment of self-initiated movement with emphasis on function with regard to sitting and walking. Incidence of hip displacement in non-ambulatory patients (GMFCS IV and V) ranges from 60% up to 90%. The adverse natural history of CP hip displacement necessitates surgery in the majority of children, which aims to obtain a pain-free, mobile, and concentrically reduced hip with symmetric range of motion, prior to the onset of painful arthritis. Hip reconstruction surgery typically involves soft tissue releases, femoral varus derotation osteotomy (VDRO), pelvic osteotomy (PO), or a combination thereof. In the literature, clear surgical indications for performing an additional acetabuloplasty after VDRO are elusive, and in practice the decision remains driven by surgeons’ experience and training. While combining VDRO and PO generally lowers resubluxation rates, some patients can safely undergo VDRO alone, thus avoiding additional surgical risk and morbidity. The first part of this thesis evaluates the effect of intraoperative hip arthrography – successfully used in Developmental Dysplasia of the Hip - as a tool for acetabuloplasty decision-making in neuromuscular hip reconstruction. Second, the revised CP definition emphasizes a holistic approach; shifting from the historical musculoskeletal focus towards incorporating comorbidities that influence patients’ health-related quality of life (HRQoL). Hip reconstruction surgery and spinal fusion aim to alleviate pain, ease caregiving, and improve HRQoL, yet their effect has been debated due to surgical complexity, postoperative risk of morbidity and patient mortality. Today, orthopedic surgeons recognize that HRQoL improvements are more meaningful to patients and caregivers than radiographic outcomes, underscoring the importance of HRQoL outcome measures. The Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD) questionnaire, validated for assessing HRQoL and caregiver burden in GMFCS levels IV and V CP patients, is increasingly used to evaluate the impact of hip and spine surgery. However, before becoming a gold standard, effective outcome instruments must also demonstrate responsiveness - the tools’ ability to detect change and remain constant across diverse cohorts. The second part of thesis assesses the responsiveness of the CPCHILD questionnaire in children with severe non-ambulatory CP undergoing hip reconstruction surgery and spinal fusion.