Is visual estimation of passive range of motion in the pediatric lower limb valid and reliable

Background: Visual estimation (VE) is an essential tool for evaluation of range of motion. Few papers discussed its validity in children orthopedics' practice. The purpose of our study was to assess validity and reliability of VE for passive range of motions (PROMs) of children's lower limbs. Methods: Fifty typically developing children (100 lower limbs) were examined. Visual estimations for PROMs of hip (flexion, adduction, abduction, internal and external rotations), knee (flexion and popliteal angle) and ankle (dorsiflexion and plantarflexion) were made by a pediatric orthopaedic surgeon (POS) and a 5(th) year resident in orthopaedics. A last year medical student did goniometric measurements. Three weeks later, same measurements were performed to assess reliability of visual estimation for each examiner. Results: Visual estimations of the POS were highly reliable for hip flexion, hip rotations and popliteal angle (rho(c) >= 0.8). Reliability was good for hip abduction, knee flexion, ankle dorsiflexion and plantarflexion (rho(c) >= 0.7) but poor for hip adduction (rho(c) = 0.5). Reproducibility for all PROMs was verified. Resident's VE showed high reliability (rho(c) >= 0.8) for hip flexion and popliteal angle. Good correlation was found for hip rotations and knee flexion (rho(c) >= 0.7). Poor results were obtained for ankle PROMs (rho(c) < 0.6) as well as hip adduction and abduction, the results of which not being reproducible. Influence of experience was clearly demonstrated for PROMs of hip rotations, adduction and abduction as well as ankle plantarflexion. Conclusion: Accuracy of VE of passive hip flexion and knee PROMs is high regardless of the examiner's experience. Same accuracy can be found for hip rotations and abduction whenever VE is performed by an experienced examiner. Goniometric evaluation is recommended for passive hip adduction and for ankle PROMs.