Session I - Combined Session (International Society for Fracture Repair)

Fri., 10/11/02 Combined Session, Paper #5, 8:47 AM

A Validated Classification System for Distraction Osteogenesis and Its Correlation with Outcome in Adolescent and Adult Limb Lengthening

Ru Li; M. Saleh; Les Coulton, MD; Orthopaedic and Traumatic Surgery Research Group; University of Sheffield, Sheffield, United Kingdom

Purpose: We designed and validated a new classification system of distraction osteogenesis and correlated the classification with healing.

Methods: A series of radiographs, taken throughout the process >from osteotomy to fixator removal, were investigated to define callus appearance and morphology. The study involved 92 patients with a mean age of 24.7 years (range, 14 to 56) and approximately 6200 radiographs (54 femoral, 71 tibial). The patients had completed limb lengthening with use of monolateral, circular, or hybrid external fixators. The mean distraction consolidation index (DCI) was 72 days/cm (SD ±42). The mean percentage length gained was 23% (SD ±19). The mean length gained was 6.5 cm (SD ±3.3). The radiographic features of the distraction osteogenesis were classified into 5 shapes and 10 classification types which reflected the density of callus in the distraction phase, early and late consolidation phase, and the callus distribution (sparse, homogenous, heterogeneous, and lucent).

Results: The classification was validated by inter- and intraobserver studies. The interobserver agreement (Kappa value) between four observers for shape was 0.51 (P<0.001), and classification type was 0.6 (P<0.001). Outcome was defined by the DCI; two groups were identified: good outcome, DCI <80 days/cm, and poor outcome, DCI >80 days/cm. The occurrence of classification type in the healing process was analyzed by use of the odds ratio and indicated the likelihood of a poor versus a good outcome. Classification types 2, 6, and 9 were indicative of a good outcome, and types 5 and 7 were indicative of a poor outcome (P<0.05).

Conclusion: This classification system is a convenient abbreviated way of describing distraction osteogenesis that can be used in clinical orthopedics to monitor progress, guide the treatment process, estimate prognosis, and predict complications.