Comparative Study of the Pain, Function, and Biomarkers of Joint Disease in the Transition to Adulthood in Individuals With and Without Cerebral Palsy

Background: Biomarkers have potential to identify early signs of joint disease. This study compared joint pain and function in adolescents and young adults with cerebral palsy compared with individuals without.Methods: This cross-sectional study compared individuals with cerebral palsy (n = 20), aged 13-30 yrs with Gross Motor Function Classification System I-III and age-matched individuals without cerebral palsy (n = 20). Knee and hip joint pain measured using Numeric Pain Rating Scale and Knee injury and Osteoarthritis Outcome Score and Hip dysfunction and Osteoarthritis Outcome Score surveys. Objective strength and function were also measured. Biomarkers for tissue turnover (serum cartilage oligomeric matrix protein, urinary C-terminal crosslinked telopeptide of type II collagen) and cartilage degradation (serum matrix metalloproteinase 1, matrix metalloproteinase 3) were measured in blood and urinary samples.Findings: Individuals with cerebral palsy had increased knee and hip joint pain, reduced leg strength, reduced walking and standing speeds, and ability to carry out activities of daily living (P < 0.005) compared with controls. They also had higher serum matrix metalloproteinase 1 (P < 0.001) and urinary C-terminal crosslinked telopeptide of type II collagen levels (P < 0.05). Individuals with cerebral palsy who were Gross Motor Function Classification System I and II demonstrated reduced hip joint pain (P = 0.02) and higher matrix metalloproteinase 1 levels (P = 0.02) compared with Gross Motor Function Classification System III.Interpretation: Individuals with cerebral palsy with less severe mobility deficits had higher matrix metalloproteinase 1 levels likely due to more prolonged exposure to abnormal joint loading forces but experienced less joint pain.