Effect of Displacement Degree of Distal Chevron Osteotomy on Metatarsal Stress: A Finite Element Method

Background: The stress of foot bone can effectively evaluate the functional damage caused by foot deformity and the results of operation. In this study, the finite element method was used to investigate the degree of displacement of distal chevron osteotomy on metatarsal stress and metatarsophalangeal joint load; Methods: Four finite element models of displacement were established by using the CT images of a patient with moderate hallux valgus (hallux valgus angle and intermetatarsal angle were 26.74° and 14.09°, respectively), and the validity of the model was verified. Each finite element model consisted of bones and various cartilage structures, ligaments, and plantar fascia, as well as encapsulated soft tissue. Except for soft tissue, the material properties of other parts were isotropic linear elastic material, and the encapsulated soft tissue was set as nonlinear hyperelastic material. The mesh was tetrahedral mesh. Link elements were used in ligament and plantar fascia. A ground reaction force with a half-body weight was applied at the bottom of the floor to simulate the ground reaction when standing. The upper surfaces of the encapsulated soft tissue, distal tibia, and distal fibula were fixed. The stress distribution of metatarsals and the stress of cartilage of the first metatarsophalangeal joint were compared and analyzed; Results: Compared with the hallux valgus without osteotomy, the stress of the first metatarsals and second metatarsals of 2–4 mm decreased, and the stress of the interarticular cartilage of the first metatarsophalangeal joint with 4 mm was reduced. In the case of 6 mm, the stress value between the first metatarsal and the first metatarsophalangeal joint increased, and 4 mm was the most suitable distance; Conclusions: Compared with the hallux valgus without osteotomy, the stress of the first metatarsals and second metatarsals of 2–4 mm decreased, and the stress of the interarticular cartilage of the first metatarsophalangeal joint with 4 mm was reduced. In the case of 6 mm, the stress value between the first metatarsal and the first metatarsophalangeal joint increased, and 4 mm was the most suitable distance. For the degree of displacement of the distal chevron osteotomy, the postoperative stability and the stress distribution of metatarsal bone should be considered. Factors such as hallux valgus angle, intermetatarsal angle, patient’s age, body weight, and metatarsal width should be considered comprehensively. The factors affecting osteotomy need to be further explored. The degree of displacement of osteotomy can be evaluated by FE method before the operation, and the most suitable distance can be obtained.

The effect of a modified chevron osteotomy for hallux valgus patients: A five-year follow-up study

Purpose This study aimed to detect the effect of a modified chevron osteotomy on hallux valgus (HV) deformity at five-year follow up. Methods Twenty patients with symptomatic HV who underwent modified chevron osteotomy between June 2014 and January 2016 were included in the present study. The follow-up duration was more than five years. Each patient was evaluated preoperatively, six weeks postoperatively and five years postoperatively using the visual analog scale (VAS) pain score, the American Orthopaedic Foot & Ankle Society (AOFAS) score and cosmetic and radiological outcomes. Results The AOFAS score improved from 54.40 (± 4.58) preoperatively to 94.30 (± 2.15) six weeks postoperatively (p < 0.001) and 96.95 (± 1.54) five years postoperatively (p < 0.001). The VAS scores decreased from 6.30 (± 1.17)preoperatively to 0.15 (± 0.37) five years postoperatively (p < 0.001). The mean intermetatarsal angle improved from 16.00° (± 2.20°) preoperatively to 4.15° (± 1.22°) six weeks postoperatively (p < 0.001) and 4.40° (± 1.39°) five years postoperatively (p < 0.001). The mean HV angle also improved, from 32.70° (± 5.34°) preoperatively to 4.80° (± 1.40°) six weeks postoperatively (p < 0.001) and 5.20° (± 1.32°) five years postoperatively (p < 0.001). The cosmetic results were either excellent or good in 19 patients (95%). There was no recurrence in this study during the five postoperative years. Conclusion A modified chevron osteotomy can achieve successful correction of moderate-to-severe HV, with excellent outcomes at five-year follow up.

Is the magnesium screw as stable as the titanium screw in the fixation of first metatarsal distal chevron osteotomy? A comparative biomechanical study on sawbones models

Background: Distal chevron osteotomy (DCO) is commonly performed in hallux valgus surgery. The fixation of the osteotomy is provided by various implants. The usage of biodegradable implants such as magnesium is gradually increasing due to the advantages they provide. In this study, we aimed to compare the fixation of DCO with magnesium or titanium screw biomechanically. Methods: Twenty sawbones were used. The samples were divided into two equal groups, including ten sawbones for fixation with single headless titanium (group-1) or magnesium screw (group-2). DCO and screw fixations were performed on all samples using the same technique. Biomechanical testing was applied to five samples in each group in cantilever and the other five in a physiological configuration using a computer connected to the electromechanical test machine. The obtained data were evaluated using the Shapiro–Wilk test, Student’s t-test and Mann–Whitney U test on the IBM® SPSS (Statistical Package for the Social Sciences) V22.0 software. Significance was accepted at the p < 0.05 level. Results: There was no statistically significant difference between the magnesium screw and the titanium screw in terms of maximum force, maximum displacement and stiffness measurements in cantilever and physiological loadings ( p > 0.05 for all). Conclusion: This study found no significant difference in biomechanical stability between the magnesium and titanium screws in DCO fixation on sawbones. Further studies with real bones are needed.

Clinico-radiological Results of Distal Chevron Osteotomy without Lateral Soft Tissue Release in Mild to Moderate Hallux Valgus Deformity

Background. The study was done to evaluate short term clinico-radiological results of distal chevron oste­otomy without lateral soft tissue release in mild to moderate hallux valgus. Materials and methods. This was a prospective study consisting of a total of 35 cases with mild to moderate hallux valgus deformity. All these patients were treated by distal chevron osteotomy without lateral soft tissue release. Results. In our study, the average value of hallux angle preoperatively was 32° (range, 24°-40°) and at final follow-up it was 14° (range, 8°-31°). The average reduction was 18°. The average intermetatarsal angle showed mean reduction of 5.3° at the final follow-up. Average range of motion of the first metatarsophalyngeal joint preoperatively and at final follow-up showed a small reduction of 5 degrees. The average preoperative AOFAS score was 49, which improved by 35 points to 84 at the final follow-up. 11.42% of the patients in the study group had a recurrence. Conclusions. 1. Based on our experience with distal chevron osteotomy without lateral soft tissue release, we found the procedure easy to perform with good procedural outcomes. 2. The possible complications of lateral soft tissue release are avoided.

First clinical experience of a new surgical technique including correction of bony alignment of first foot ray combined with reconstruction of muscle balance in case of adolescent hallux valgus

BACKGROUND: Hallux valgus deformity of the big toe in adolescents accounts for 22%44% of all relevant cases. Despite a relatively large number of surgical treatment methods proposed to correct this deformity, treatment results are not always satisfactory. The problem of imbalance between the external traction of the abductor hallucis muscle and the contracted adductor muscle in hallux valgus remains controversial and is not covered in the literature. AIM: This study aimed to examine the results of hallux valgus deformity treatment, following the suggested combined technique. MATERIALS AND METHODS: Eight teenage patients (10 feet), aged 15 years on average, were assessed. Patients were undergoing treatment in the department of pediatric orthopedics of the Dana Hospital, Tel Aviv, within the period from 2015 to 2019. The average postoperative observation period was 30 months. This study suggested a new combined technique, including (1) modified oblique Chevron osteotomy with a V-shaped cut in the distal aspect of the first metatarsal with the dorsal wedge excision performed at the apex of its angulation, (2) valgus osteotomy of the medial cuneiform bone with the insertion of the V-shaped bone allograft, and (3) transfer of the dorsal portion of the pre-split tendon of abductor hallucis muscle to the base of the triangular medial capsular flap of the first metatarsophalangeal joint (MPJ). The tendon received optimal tension to restore the muscular balance. RESULTS: This surgical technique provided safe and stable correction of the hallux valgus deformity, restored muscular balance, avoided movement restriction of the first MPJ, and restored the function and strength of the abductor halluces muscle that prevented the recurrence of the deformity. The number of good and excellent results was much greater than those in published reports. CONCLUSIONS: Despite a relatively small group of patients, the suggested technique has shown improvements in hallux valgus deformity in adolescents.

Association of Visual Appearance on Outcomes After Hallux Valgus Surgery

Background: In this study, our aim was to determine the effect of cosmetic improvement on patient satisfaction and functional scores in hallux valgus (HV) surgery. Methods: Preoperative foot photographs of 105 patients who had undergone chevron osteotomy for HV between 2016 and 2018 were taken. The patients were divided into 2 groups. Twenty-four months after surgery, the preoperative foot photographs were shown to patients in group 1 (n = 52) but not to patients in group 2 (n = 53). The groups were then compared using the visual analog scale (VAS), the American Orthopaedic Foot & Ankle Society Hallux Metatarsophalangeal-Interphalangeal (AOFAS Hallux MTP-IP), and the 36-Item Short Form Health Survey (SF-36) scores. Both groups were evaluated radiologically with preoperative and postoperative hallux valgus angles and intermetatarsal angles. Results: There was no difference between the 2 groups in terms of radiologic parameters either pre- or postoperatively, or AOFAS Hallux MTP-IP scores postoperatively. However, for group 1, the VAS was lower (0.4±0.8 vs 1.8±1.6, P = .003) and both the SF-36 physical functioning (88.3±18.1 vs 79.1±23.2, P = .017) and SF-36 mental health scores were higher (78.8±19 vs 69.2±16.3, P = .022). Conclusion: Visualizing improvement in the cosmetic appearance of the foot appears associated with patients’ perception of subjective pain and functional improvement. We recommend that preoperative foot photographs be taken and recorded. Level of Evidence: Level III, case-control study.