Prediction of normal bone anatomy for the planning of corrective osteotomies of malunited forearm bones using a three‐dimensional statistical shape model

Abstract

Corrective osteotomies of the forearm based on 3D computer simulation using contralateral anatomy as a reconstruction template is an approved method. Limitations are existing considerable differences between left and right forearms, and that a healthy contralateral anatomy is required. We evaluated if a computer model, not relying on the contralateral anatomy, may replace the current method by predicting the pre-traumatic healthy shape. A statistical shape model (SSM) was generated from a set of 59 CT scans of healthy forearms, encoding the normal anatomical variations. Three different configurations were simulated to predict the pre-traumatic shape with the SSM (cross-validation). In the first two, only the distal or proximal 50% of the radius were considered as pathological. In a third configuration, the entire radius was assumed to be pathological, only the ulna being intact. Corresponding experiments were performed with the ulna. Accuracy of the prediction was assessed by comparing the predicted bone with the healthy model. For the radius, mean rotation accuracy of the prediction between 2.9 ± 2.2° and 4.0 ± 3.1° in pronation/supination, 0.4 ± 0.3° and 0.6 ± 0.5° in flexion/extension, between 0.5 ± 0.3° and 0.5 ± 0.4° in radial-/ulnarduction. Mean translation accuracy along the same axes between 0.8 ± 0.7 and 1.0 ± 0.8 mm, 0.5 ± 0.4 and 0.6 ± 0.4 mm, 0.6 ± 0.4 and 0.6 ± 0.5 mm, respectively. For the ulna, mean rotation accuracy between 2.4 ± 1.9° and 4.7 ± 3.8° in pronation/supination, 0.3 ± 0.3° and 0.8 ± 0.6° in flexion/extension, 0.3 ± 0.2° and 0.7 ± 0.6° in radial-/ulnarduction. Mean translation accuracy between 0.6 ± 0.4 mm and 1.3 ± 0.9 mm, 0.4 ± 0.4 mm and 0.7 ± 0.5 mm, 0.5 ± 0.4 mm and 0.8 ± 0.6 mm, respectively. This technique provided high accuracy, and may replace the current method, if validated in clinical studies. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2630-2636, 2017.

Restoration of the Patient-Specific Anatomy of the Proximal and Distal Parts of the Humerus

“…The contralateral anatomy has been proposed as the best available reconstruction template 4,7,[27][28][29] . Furthermore, recent studies have highlighted the potential of SSMs for predicting the normal bone anatomy 5,30 . We evaluated whether an SSM has the potential to accurately predict the pretraumatic anatomy of the proximal and distal parts of the humerus.…”

Evaluation of Statistical Shape Modeling in Quantifying Femoral Morphologic Differences Between Symptomatic and Nonsymptomatic Hips in Patients with Unilateral Femoroacetabular Impingement Syndrome

“…10 In orthopedics, SSM has been used to better understand pathoanatomy and create de novo 3D renderings for reconstructing the mandible, spine, wrist, forearm, knee, and shoulder. [8][9][10]12,13,[15][16][17] With respect to the proximal femur, SSM has been used to characterize changes seen with slipped capital femoral epiphysis and Legg-Calve-Perthes disease as well as to characterize hip fracture risk in the elderly. 9,13 The utility of SSM has also been applied to cam lesions and to normal and pathologic hips.…”

Towards Automated Ligamentous Injury Evaluation in Syndesmotic Ankle Lesions

“…Acclaimed for their ability to reduce data dimensionality, statistical shape models (SSM) are well-suited for 3D shape correlation to predict patient-specific missing anatomical information (19). In this context, SSM has already been efficiently utilized for computerassisted Anterior Cruciate Ligament (ACL) reconstruction (20), virtual reconstruction of acetabular bone defects (21) and planning of corrective osteotomies for malunited forearm bones (22).…”