Reza Abdi - Orthopedic Research Center, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
Omid Shahpari - Orthopedic Research Center, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
Farshid Bagheri - Orthopedic Research Center, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
Ramin Zargarbashi - Orthopedic Research Center, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran

Objectives: The most critical step in the calculation of final limb length discrepancy (LLD) is estimatingthe length of the short limb after skeletal maturity(Sm). Paley's multiplier method is a fast, convenientmethod for calculating Sm and LLD after skeletal maturity; nonetheless, the calculation of the processof Sm and LLD in acquired type cases is complex in contrast to congenital type in this method.Notwithstanding. The multiplier method uses a variable called "growth inhibition" for the calculationprocess in acquired type LLD; however, its mathematical proof has not been published yet. The presentstudy aims to find out whether there is an alternative way to estimate the length of Sm and LLD inskeletal maturity without using growth inhibition (GI) and its com plex calculation process in acquiredtype LLD.Methods: We used trigonometric equations to prove the GI concept and conducted proportionality analysis tocalculate the length of short limbs and LLD in skeletal maturity without using GI.Results: Based on the results, the following proportionality can estimate the length of the short limb in skeletalmaturity. (ΔLm/ΔL = ΔSm/ΔS)Conclusion: The GI concept can be proved trigonometrically; nonetheless, its numerical value is not necessary forestimating the length of the short limb in skeletal maturity. Instead, a simple proportionality analysis serves thepurpose of calculation. Level of evidence: II

Limb length discrepancy, Method skeletal maturity, Paley's multiplier