Forearm Length – A New Tool to Standardize Bone Parameters of the Forearm Measured with Peripheral Quantitative Computed Tomography in Individuals with Disproportional Growth of Forearm Length and Body Height

Abstract

Aim: To investigate the relationship of forearm length (FL) or height to bone parameters of the forearm of a normal pediatric population in comparison to individuals with osteogenesis imperfecta (OI). Methods: Data on FL, height and peripheral quantitative computed tomography measurements of the forearm were collected from participants of the DONALD study (140 males and 156 females; age 5–19 years) and from 73 patients with OI (53 males; mean age ± SD: 11.7 ± 3.3 years). Bone mineral content (BMC) was transformed into standard deviation score (SDS) according to height or FL. Results: Height and Tanner stages significantly predicted FL in males (R²_adjusted = 0.960) and females (R²_adjusted = 0.934). Height was a stronger predictor of FL than Tanner stages. Compared to controls, patients with OI were characterized by lower BMC-SDS_FL and lower BMC-SDS_height (–0.37 ± 1.77 vs. 0.00 ± 0.97, p = 0.002, and –0.15 ± 5.0 vs. –0.02 ± 1.01, p = 0.011, respectively). BMC-SDS_FL was not significantly lower than BMC-SDS_height in controls, and also not lower in patients with OI (p = 0.865 and p = 0.809). The height/FL ratio was significantly decreased in patients with OI (mean ± SD: 6.34 ± 0.38 vs. 6.45 ± 0.21, p = 0.001) compared with controls. Conclusion: Because of disproportional growth, BMC may be overestimated in OI patients.

Analysis of limb segments length and body proportion of southern Chinese children and adolescents

“…For example, a high sitting height to height ratio (or low upper/lower segment ratio) is suggestive of skeletal dysplasia and an excessively high extremities to trunk ratio implies disproportionately short trunk, such as spina epiphyseal dysplasia . A low arm span and short forearms are suggestive of a defect in the SHOX gene . Interestingly, the difference in height among different socio‐economic classes are primarily because of increase in leg length and not an increase in sitting height and prior studies have found a strong correlation between lower segment measurements and height …”

Pilot Study for Reconstruction of Soft Tissues: Muscle Cross‐Sectional Area of the Forearm Estimated from Cortical Bone for a Neolithic Sample

“…Data on the individual professions of the participants are not available. For more information on the study please see http://www.fke-do.de and the publications of Schoenau et al, (; see also Rauch et al, ; Fricke et al, ). Due to study design, only the radius and the muscle cross‐sectional area of the nondominant forearm were measured.…”

“…Even though it is today common to standardize cortical bone properties of the lower limbs by the product of body mass and bone length (following Ruff, ), the most appropriate method of standardization is still under debate (Trinkaus and Ruff, ). However, while there is strong evidence that for weight bearing limbs standardization by body mass is the best method so far (Ruff et al, ), it has been demonstrated that muscle and bone properties of the radius are not significantly influenced by weight (Fricke et al, ). In medicine, pQCT values are often standardized by forearm length (see, e.g., Fricke et al, ) or stature (see, e.g., Schoenau, ; Schoenau and Fricke, ).…”

“…Muscle cross‐sectional area alone may not be mistaken as a direct equivalent for the “strength” of an individual. In the forearm, “strength” in terms of grip or tensile force is the result of both muscle cross‐sectional area and forearm length (Fricke et al, ). Due to the leverage effect an individual with longer limbs is provided with a biomechanical advantage and needs a smaller muscle cross‐sectional area for generating equal forces than an individual with shorter limbs.…”

“…Due to the leverage effect an individual with longer limbs is provided with a biomechanical advantage and needs a smaller muscle cross‐sectional area for generating equal forces than an individual with shorter limbs. Therefore, estimations of muscle cross‐sectional area have to be standardized by forearm length to provide information on the physical capabilities of the forearm and on the stresses placed on the individual during lifetime (Ruff et al, ; Churchill, ; Trinkaus and Churchill, ; Schoenau et al, ; Schoenau, ; Fricke et al, ). Muscle cross‐sectional area of the forearm standardized by radius length provides us with a surrogate for forearm force production capability and tells us about the stresses placed on the forearm of the individual during lifetime.…”