Growth factors in human serum during operative tibial lengthening with the Ilizarov method

The Ilizarov technique in treating denervated ankle-foot deformities

Background:

Neurological injuries or diseases may cause ankle-foot deformities that seriously affect patients’ quality of life.

Objective:

This study aimed to explore the feasibility of the Ilizarov technique for treating complex ankle-foot deformity with neurotrophic disorders.

Methods:

In this retrospective study, 10 patients, including 6 males and 4 females, with complex ankle-foot deformities with nerve injury were treated from January 2014 to May 2019. The age of the patients ranged from 13 to 57 years with an average of 27.9 years. The reasons of nerve injury were as follows: sequelae of spina bifida in five patients, post-traumatic injury of the common peroneal nerve and tibial nerve in four patients, and subacute degeneration of the spinal cord in one patient. Minimally invasive surgery was used for osteotomy, muscle strength balance, and external ring frame fixation, and various deformities were gradually corrected after the operation. The ankle- foot function was evaluated using the American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score before surgery and at long-term follow-up after surgery.

Results

: All 10 patients were followed up for 12 months to 3 years, with an average of 1.9 years. The deformities of all 10 patients were corrected; and of the 10 patients, three partially recovered their nerve function. A significant difference (p < 0.001) between the AOFAS score (81.6 ± 10.45) evaluated in the long-term follow-up and that evaluated preoperatively (31.1 ± 14.69). The AOFAS comprehensive score was excellent in two patients, good in six patients, and fair in two patients.

Conclusion:

The Ilizarov technique combined with minimally invasive osteotomy and muscle strength balance could safely correct complex ankle-foot deformities with neurotrophic disorders.

MiR-503 Promotes Bone Formation in Distraction Osteogenesis through Suppressing Smurf1 Expression

Distraction osteogenesis (DO) is a unique technique for promoting bone formation in clinical practice. However the underlying mechanism remains elusive. As epigenetic mediators, microRNAs have been reported to play important roles in regulating osteogenesis. In this study, after successfully established the DO model of rats, a microRNA microarray was performed to find molecular targets for DO. Total 100 microRNAs were identified as differently expressed, with miR-503 being one of the most significantly up-regulated miRNAs in DO. The further investigation also showed that miR-503 was upregulated during osteogenesis in mesenchymal stem cells of rats, and overexpression of miR-503 significantly promoted osteogenesis in vitro and accelerated mineralization in DO process in vivo. By using bioinformatic investigations and luciferase activities, we successfully demonstrated that Smurf1, a negative regulator of osteogenesis, was a real target of miR-503. Furthermore, Smurf1 knockdown promoted osteogenesis and antagomir-503 abolished the promotive effect, suggesting that miR-503 mediated osteogenic differentiation via suppressing Smurf1 expression. To sum up, these findings indicated that miR-503 promoted osteogenesis and accelerated bone formation, which may shed light on the development for a potential therapeutic target for bone repair.