Biomechanical Comparison between Rotational Scarf Osteotomy and Translational Scarf Osteotomy: A Finite Element Analysis

ObjectiveRotational Scarf osteotomy has its unique advantages in treating hallux valgus, but it also has certain drawbacks. The biomechanical differences between rotational Scarf and translational Scarf osteotomy are not clear evaluates the correction ability and biomechanical difference of two surgical methods for hallux valgus by finite element analysis.MethodsThe computerized tomography data of a hallux valgus patient were selected to establish a finite element model. The standard Scarf osteotomy was simulated based on the model, and the rotation and translation were performed, respectively. The size of the intermetatarsal angle, contact area, distal metatarsal articular angle and the absolute length of the first metatarsal was compared between the two groups. We completed the cartilage, ligament and other tissues on the bone model to establish a full foot model. We analyzed the troughing, plantar aponeurosis tension, plantar soft tissue, and ground stress and also observed the stability of the fracture site by a three-point bending test.ResultsBoth surgical methods may effectively correct the intermetatarsal angle. After rotational osteotomy, the contact area increased, and the length of the first metatarsal bone initially increased and then decreased compared to that in the translational group. Furthermore, rotational Scarf significantly increased the distal metatarsal articular angle. Mechanical analysis showed that the cancellous bone in the contact part of the fracture site in the translation group had greater stress, which was the reason for the occurrence of the troughing. Stress distribution of plantar aponeurosis, plantar soft tissue, and the ground showed no significant difference. The three-point bending test showed that the separation of the broken ends of the rotational Scarf osteotomy model (0.133 mm) was slightly smaller than the translational group (0.147 mm).ConclusionBoth surgical methods can successfully correct intermetatarsal angle (IMA). Compared to traditional translational Scarf osteotomy, rotational Scarf osteotomy is more conducive to postoperative stability and healing, but it also has certain drawbacks. In clinical practice, individualized surgical methods still need to be selected for different types of patients with hallux valgus. This study aimed to elucidate the biomechanical differences between traditional translational Scarf osteotomy and a newly proposed rotational Scarf osteotomy for the treatment of hallux valgus (HV). Using finite element analysis, we developed an HV model with a Z-shaped bone cut to simulate rotational Scarf and translational Scarf osteotomy. We believe that our study makes a significant contribution to the literature because we have elucidated some of the biomechanical differences between rotational Scarf and translational Scarf and have clarified the efficacy of this procedure for HV patients.image