Bone Abstracts

Objectives: Children with Perthes disease may present with altered walking patterns even at the healed stage of the disease. The aim of the study was to assess the walking endurance, fatiguability and gait changes of children with healed Perthes disease, and to determine if walking endurance is associated with hip function and quality of life.

Methods: Fifty-one children (38 males) aged 8–16 years with >3 years post-diagnosis of Perthes disease completed this cross-sectional study. Normative data was extracted from a contemporary Australian data set (1000 Norms Project) including 152 similarly aged children (76 males). Walking endurance was assessed with the six minute walk test (6MWT) with temporo-spatial gait parameters recorded throughout by the GAITRite system. The Non-arthritic hip score (NAHS) and Global Paediatric Outcomes Data Collection Instrument (PODCI) were also completed.

Results: In comparison to healthy peers, children with healed Perthes disease exhibited significantly reduced walking endurance (6MWT mean difference 181.2 m, 95% CI 152.4 – 210, P<0.01). No fatiguability was seen during the 6MWT with no significant difference observed between the distance covered in the first and last minute (mean difference 0.05 m, 95% CI −6.19 – −6.29 m, P=0.98) or the cumulative distance between the first three and last three minutes (mean difference 1.94 m, 95% CI −12.6 – 16.48 m, P=0.49). Children with unilateral disease (n=43) walked significantly faster (mean difference 0.14 m/s, 95% CI 0.07 – 0.21 m/s, P<0.01) with a higher cadence (mean difference 9.3 steps/min, 95% CI 1.1 – 17.4 steps/min, P<0.01) compared to children with bilateral disease (n=8). Overall, children with Perthes disease reported excellent hip and global function (NAHS mean score 94.4/100; PODCI mean score 90.7/100), with higher scores moderately correlated with greater walking distances (r²=0.46 – 0.49, all P<0.01).

Conclusion: Children with Perthes disease have reduced overall walking endurance in comparison to healthy peers. However, they perceive their hip function to be high. Although gait fatiguability was not established during the 6MWT, children with bilateral involvement demonstrated an altered gait strategy to children with unilateral disease. Walking endurance and quality should be considered in the long term outcome assessment of the management of Perthes disease.

Disclosure: The authors declared no competing interests.