Functional Outcome of Varus Derotation Osteotomy in Legg-Calve-Perthes Disease: Can It Be Justified in Late-Presenting Disease?

Background: Legg-Calve-Perthes disease (LCPD) in children older than seven years has often been associated with accelerated progress and poor outcome. The results of varus derotation osteotomy (VDRO) of the proximal femur in this cohort are not consistently predictable. This study was aimed at assessing the functional outcome of VDRO for hip containment in children with late-presenting LCPD.Materials and methods: A quasi-prospective observational study was conducted to determine the functional outcomes of children with late-presenting unilateral LCPD who underwent VDRO between 2016 and 2021, with a minimum follow-up of two years. A retrospective chart review followed by a patient/parent-reported outcome measure using the Paediatric Outcome Data Collection Instrument (PODCI) was utilised.Results: Thirteen children were included in this study, with a mean age of 8.30 years (range: 7-12 years; SD:-1.493). Three children were in the early stages of the disease, modified Elizabethtown I and IIA (1 and 2, respectively). The majority of the children were in Stage IIB of the modified Elizabethtown staging (n=6), followed by Stage IIIA (n=4). The two children presenting in Stage IV of the disease were excluded from the analysis. The mean standardised and normative PODCI scores for transfer and mobility were 98.23 and 48.03, respectively. The mean standardised and normative PODCI scores for sports and physical were 93.15 and 49.76, respectively. Neither of the scores showed a statistically significant difference between the late and early stages of the disease (Transfer and Basic Mobility Scale: Standardised (p=0.273), Normative (p=0.268); Sports and Physical Functioning Scale: Standardised (p=0.618), Normative (p=0.631)). However, a higher mean PODCI score was noted for the early stages. There was no statistically significant difference between the median score and the duration since surgery. However, there was a moderate negative correlation between the time scores and the times since surgery for the late stages of the disease, viz. Stage IIB and IIIA (Transfer and Basic Mobility Scale: Standardised (-0.445), Normative (-0.450); Sports and Physical Functioning Scale: Standardised (-0.228), Normative (-0.228)). This correlation, however, did not reach a statistical significance.Conclusion: VDRO can be regarded as a functionally rewarding option for femoral head containment in late presenting LCPD across the evolutionary stages of the disease.