PURPOSE: Limb-length discrepancy occurs in both the upper and lower extremities. Methods of predicting discrepancies at skeletal maturity have generally focused on the lower limbs. Paley et al devised the multiplier method to predict lower-limb-length discrepancy at skeletal maturity. The purpose of this study was to generate a similar methodology applicable for the upper limb. METHODS: Using radiographic, clinical, and anthropologic databases, we divided humeral, radial, and ulnar lengths at skeletal maturity by the humeral, radial, and ulnar lengths at each age and for each percentile given. The multipliers for the radius, the ulna, and the humerus were compared with each other. The multipliers also were compared based on percentile, ethnic and racial group, nationality, and anthropologic data. RESULTS: The multipliers for the humerus, radius, and ulna were equivalent in all percentile groups, varying only by age and gender after 1 year of age. The multipliers of different national and racial groups also were the same. The upper-extremity multipliers calculated from anthropologic data were very similar. CONCLUSIONS: The multiplier method is a quick and easy method of predicting upper-limb growth. It is simpler to use than previous methods and is independent of percentile, generation, ethnicity, nationality, and race. The upper-extremity multiplier can be used to determine timing of epiphysiodesis and predict bone length at skeletal maturity, growth remaining, and congenital and developmental limb-length discrepancy. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.
PURPOSE: Limb-length discrepancy occurs in both the upper and lower extremities. Methods of predicting discrepancies at skeletal maturity have generally focused on the lower limbs. Paley et al devised the multiplier method to predict lower-limb-length discrepancy at skeletal maturity. The purpose of this study was to generate a similar methodology applicable for the upper limb. METHODS: Using radiographic, clinical, and anthropologic databases, we divided humeral, radial, and ulnar lengths at skeletal maturity by the humeral, radial, and ulnar lengths at each age and for each percentile given. The multipliers for the radius, the ulna, and the humerus were compared with each other. The multipliers also were compared based on percentile, ethnic and racial group, nationality, and anthropologic data. RESULTS: The multipliers for the humerus, radius, and ulna were equivalent in all percentile groups, varying only by age and gender after 1 year of age. The multipliers of different national and racial groups also were the same. The upper-extremity multipliers calculated from anthropologic data were very similar. CONCLUSIONS: The multiplier method is a quick and easy method of predicting upper-limb growth. It is simpler to use than previous methods and is independent of percentile, generation, ethnicity, nationality, and race. The upper-extremity multiplier can be used to determine timing of epiphysiodesis and predict bone length at skeletal maturity, growth remaining, and congenital and developmental limb-length discrepancy. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.