Yunan Lu1, Federico Canavese2, Ran Lin1, Yuling Huang1, Xinwu Wu1, Binbin Lin1, Shunyou Chen3,4. 1. Department of Paediatric Orthopaedics, Fuzhou Second Hospital, The Third Clinical Medical College, Fujian Medical University, Fuzhou Second Hospital of Xiamen University, School of Medicine, Xiamen University, 47th Shangteng Road of Cangshan District, Fuzhou, 350007, Fujian Province, China. 2. Department of Paediatric Orthopaedic Surgery, Lille University Centre, Jeanne de Flandre Hospital, Rue Eugène Avinée, 59000, Lille, France. 3. Department of Paediatric Orthopaedics, Fuzhou Second Hospital, The Third Clinical Medical College, Fujian Medical University, Fuzhou Second Hospital of Xiamen University, School of Medicine, Xiamen University, 47th Shangteng Road of Cangshan District, Fuzhou, 350007, Fujian Province, China. csy508@163.com. 4. Fujian Provincial Clinical Medical Research Center for First Aid and Rehabilitation in Orthopaedic Trauma (2020Y2014), Fuzhou, 350007, China. csy508@163.com.
Abstract
BACKGROUND: Ulna distraction by monolateral external fixator (MEFix) is a good option for the treatment of Masada type I and IIb deformities in children with hereditary multiple exostoses (HMEs). However, there is no consensus regarding where to perform ulnar osteotomy. Our hypothesis is that osteotomy at the proximal third of the ulna and progressive distraction with MEFix can simultaneously correct elbow and wrist deformities in patients with HME. METHODS: We retrospectively reviewed patients with HME who underwent ulna distraction osteogenesis from June 2014 to March 2019. The carrying angle (CA), radial articular angle (RAA), ulnar variance (UV), radial variance (RV) and range of motion (ROM) of the affected forearm and elbow were clinically assessed before lengthening and at the last follow-up visit. The total ulna lengthening distance (LD) and radiographic outcome were also recorded. RESULTS: Nineteen patients (20 forearms) with HME aged 9.1 ± 2.4 years at the time of surgery were retrospectively reviewed. The mean follow-up period was 26.1 ± 5.6 months. There were 11 patients (12 forearms) with Masada type I deformities and eight patients (8 forearms) with Masada type IIb deformities. Patients with type IIb deformity had higher RV, lower CA values, less elbow flexion and forearm pronosupination than those with type I deformity (p < 0.05); RV was an independent risk factor for radial head dislocation, with the cut off at RV > 15.5 mm. The mean LDs in patients with type I and type IIb deformities were 33.6 ± 6.6 mm and 41.4 ± 5.4 mm, respectively. The mean CA, UV, RV, forearm pronation and ulna deviation at the wrist improved significantly following surgery in all patients. In particular, five of eight patients (62.5%) with type IIb deformities had concentric reduction of the radiocapitellar joint, while no radial head subluxation was detected in patients with type I deformities at the last follow-up. Three complications were recorded: two pin-track infections and one delayed union. CONCLUSIONS: Distraction osteogenesis at the proximal third of the ulna provides satisfactory clinical and radiological outcomes in patients with Masada type I and IIb deformities. Early treatment of Masada type I deformities is indicated before progression to more complex type IIb deformities.
BACKGROUND: Ulna distraction by monolateral external fixator (MEFix) is a good option for the treatment of Masada type I and IIb deformities in children with hereditary multiple exostoses (HMEs). However, there is no consensus regarding where to perform ulnar osteotomy. Our hypothesis is that osteotomy at the proximal third of the ulna and progressive distraction with MEFix can simultaneously correct elbow and wrist deformities in patients with HME. METHODS: We retrospectively reviewed patients with HME who underwent ulna distraction osteogenesis from June 2014 to March 2019. The carrying angle (CA), radial articular angle (RAA), ulnar variance (UV), radial variance (RV) and range of motion (ROM) of the affected forearm and elbow were clinically assessed before lengthening and at the last follow-up visit. The total ulna lengthening distance (LD) and radiographic outcome were also recorded. RESULTS: Nineteen patients (20 forearms) with HME aged 9.1 ± 2.4 years at the time of surgery were retrospectively reviewed. The mean follow-up period was 26.1 ± 5.6 months. There were 11 patients (12 forearms) with Masada type I deformities and eight patients (8 forearms) with Masada type IIb deformities. Patients with type IIb deformity had higher RV, lower CA values, less elbow flexion and forearm pronosupination than those with type I deformity (p < 0.05); RV was an independent risk factor for radial head dislocation, with the cut off at RV > 15.5 mm. The mean LDs in patients with type I and type IIb deformities were 33.6 ± 6.6 mm and 41.4 ± 5.4 mm, respectively. The mean CA, UV, RV, forearm pronation and ulna deviation at the wrist improved significantly following surgery in all patients. In particular, five of eight patients (62.5%) with type IIb deformities had concentric reduction of the radiocapitellar joint, while no radial head subluxation was detected in patients with type I deformities at the last follow-up. Three complications were recorded: two pin-track infections and one delayed union. CONCLUSIONS: Distraction osteogenesis at the proximal third of the ulna provides satisfactory clinical and radiological outcomes in patients with Masada type I and IIb deformities. Early treatment of Masada type I deformities is indicated before progression to more complex type IIb deformities.