Modified ulnar lengthening for correction of the Masada type 2 forearm deformity in hereditary multiple exostosis.

Few articles have reported on the treatment of Masada type 2 forearm deformities in hereditary multiple exostosis, possibly because of the high redislocation rate and other complications. This study precisely declares the use of modified ulnar lengthening by an Ilizarov external fixation with tumour excision for the treatment of Masada type 2 forearm deformities. 20 children with Masada type 2 forearm deformities were admitted for surgical treatment at our hospital from February 2014 to February 2021. There were 13 girls and 7 boys, ranging in age from 3.5 to 15 years (mean: 9 years) at the time of operation. We removed the prominent osteochondromas of the distal ulna and the proximal radius, positioned a classic Ilizarov external fixator on the forearm and then performed ulnar transverse one-third proximal diaphyseal subperiosteal osteotomy. We adopted modified ulnar lengthening postoperatively. The effects of surgical correction of deformity and functional improvement of the limb were assessed via regular follow-up and X-ray. The patients were followed up for 36 months, and the ulna was lengthened 26.99 mm on average; all radial heads remained relocated. The radiographic evaluations, including relative ulnar shortening, radial articular angle, and carpal slip, were improved. The functions of the elbow and forearm were all improved after surgery. Modified ulnar lengthening by an Ilizarov external fixation with tumour excision for the treatment of Masada type 2 forearm deformities in hereditary multiple exostoses has been proven to be an effective and reliable technique in the early stage.

[The effect of different intensity exercise on skeletal muscle fiber MHC subtype transformation and CaN/NFATc1 signaling pathways].

OBJECTIVE: To study the effect of different intensity exercise on skeletal muscle fiber myosin heavy chain(MHC) subtype transformation and CaN/NFATc1 signaling pathways. METHODS: Twenty-four Male SD rats (2-month old) were randomly divided into normal control group (NC), moderate intensity exercise group (ME, grade 5°, speed 18 m/min), heavy intensity exercise group (HE, grade 10°, 26.8 m/min). The rats in exercise groups were treated with treadmill training for eight weeks. The type I and type Ⅱ muscle fibers were determined by ATPase staining method. MHC subtype was separated by SDS-PAGE. The activity of CaN was determined by colorimetric method. The content of NFATc1 protein in skeletal muscle was detected by immune imprinting technology. RESULTS: ①Skeletal muscle fiber density changes:the type I and Ⅱ fiber number density of quadriceps in ME group were increased significantly (P<0.05), but in HE group, only the type Ⅱ fiber surface density was increased significantly (P<0.05). The type I fiber number density of soleus in ME and HE group was increased significantly (P<0.05). ②The changes of fibers MHC subtype percentage in skeletal muscle:the percentages of MHC I and type Ⅱa of quadriceps in ME group were increased (P<0.05), while the percentage of MHC Ⅱb was decrease (P<0.05). The percentage of MHC I in soleus was increased, while the percentages of MHCⅡa and Ⅱb were decreased. ③The activity of CaN and the content of NFATc1 protein in ME group were increased significantly (P<0.05). CONCLUSIONS: The heavy and moderate intensity exercise may induce skeletal muscle MHC type transforming from fast to slow. At the same time, the activity of CaN and the expression of NFATc1 protein are increased accompanying the changes of skeletal muscle fibers subtype.