Variety is Not the Spice of Life: Inconsistent Definitions of Failure After Hip Reconstruction in Cerebral Palsy

Hip displacement (subluxation or dislocation) is common in children with cerebral palsy (CP), especially those who are nonambulatory. If unaddressed, this can cause pain, stiffness, hygiene difficulties, and seating imbalance. Progressive hip subluxation or dislocation often requires surgery, and further displacement after reconstruction may be described as "failure." There is currently no standardized definition of failure after the index procedure. This review aimed to identify published failure definitions and compile reported failure rates after index bony hip reconstruction.

Following PRISMA guidelines, a systematic review was performed using PubMed, SCOPUS, and OVID databases (1990 to 2023). Exclusion criteria included soft tissue-only procedures, gait analysis-based outcomes, adults, non-CP syndromes, salvage or arthroplasty procedures, nonoperative management, unavailable full-text, non-English articles, novel techniques, radiographic or morphologic studies, or procedures without osteotomy. Studies without a definition of "failure" were excluded. Abstract review, full-text screening, and data extraction were performed by 2 authors, with a third adjudicating disagreements. Patient demographics, failure definitions and rates, and study quality were collected. Bias was assessed, and data were considered for pooled analysis.

Of 630 abstracts, 27 studies were included. Failure rates ranged from 1.8% to 74% (mean 26.3%±17.4%). Definitions varied: Reimer Migration Percentage (MP) (63%) and revision surgery (48%) were most common. Other definitions included arthritis/hip pain (18.5%) and lateral center edge angle (18.5%). Significant heterogeneity in definitions, inclusion criteria, and follow-up, plus overlapping patient cohorts, precluded meta-analysis. The lowest rate (1.8%) reflected a single revision for painful instability. The highest (74%) came from a study defining failure as reoperation without MP. Two institutions contributed 6 publications.

There is no consistent definition of failure after bony hip reconstruction in CP, impeding comparison of techniques and outcomes. Children with CP are medically complex, and revision surgeries have significant implications. We advocate for a more uniform definition of failure following hip reconstruction in children with CP.

Level III-systematic review of studies.