Fixation of Unstable Osteochondritis Dissecans Lesions and Displaced Osteochondral Fragments Using New Biodegradable Magnesium Pins in Adolescents.

OBJECTIVE: Fixation of unstable osteochondritis dissecans (OCD) lesions and displaced osteochondral fragments are frequently performed procedures in pediatric orthopedic surgery. Since 2018, CE-certified MAGNEZIX pins are used in our institution in these cases. The aim of this study was (1) to analyze safety, efficiency, and limitations of magnesium-pin-based fixation of unstable OCD lesions and displaced osteochondral fragments and (2) to report clinical and radiological outcomes at short-term follow-up (FU). DESIGN: In this prospective cohort study, 19 patients (10 girls and 9 boys) were included. Inclusion criteria were (1) magnetic resonance imaging-confirmed unstable OCD lesion or displaced osteochondral fragment, (2) fixation with magnesium-based pins, and (3) minimum FU of 6 months. X-rays were taken 6 weeks and 6 months after operation and magnetic resonance imaging scans every 4 to 6 months to assess the healing progress. RESULTS: In total 67 pins were used, with a mean of 3.6 ± 1.4 per patient. Average age at surgery was 13.7 years (11-17 years). Mean time of operation was 56 ± 31 minutes, including arthroscopy, fixation, and patellar realignment (n = 6). No intraoperative complications occurred. Average FU was 11.3 ± 4.2 months (6-20 months). No redislocation or new dislocation occurred. Until now a complete radiographic healing occurred in 12 cases. Due to an implant failure in one case 11 weeks after the index surgery a revision became necessary. CONCLUSIONS: In short-term FU of 11 ± 4 months MAGNEZIX pins provide high stability after fixation of unstable OCDs and displaced osteochondral fragments leading to uncomplicated and timely healing.

The Use of Bovine Xenogeneic Bone Graft for Dega Pelvic Osteotomy in Children with Hip Dysplasia: A Retrospective Study of 147 Treated Hips.

BACKGROUNDS: Dega pelvic osteotomy is commonly used to correct acetabular dysplasia in children with open triradiate cartilage. The use of bovine xenogeneic bone graft (Tutobone®) for Dega osteotomy has not been reported so far. This study aimed to determine the clinical and radiological outcome in a large series of children with hip dysplasia who were treated by Dega osteotomy using a bovine xenogeneic block for stabilisation. METHODS: A retrospective, single-centre study was conducted including 101 patients (147 hips) with different underlying diseases. The acetabular angle of Hilgenreiner (AA) and the lateral center-edge angle (LCA) were analysed to quantify the correction of acetabular indices. Graft incorporation was assessed using the Goldberg scoring system. RESULTS: the mean preoperative AA improved from 28.1 (SD: 6.7) to 14.7 (SD: 5.1) after surgery (p < 0.001). The mean preoperative LCA improved from 9.9 (SD: 6.7) to 21.8 (SD: 6.8) postoperatively (p < 0.001). Both indices remained stable at the one-year follow-up examination. Graft incorporation was excellent with a mean Goldberg score of 6.6. Heterotopic ossification occurred in one hip without clinical relevance. Graft-related complications were not noted. CONCLUSIONS: Dega osteotomy using Tutobone® is safe and effective in the treatment of acetabular dysplasia in children independent of the underlying disease.

Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up.

OBJECTIVE: Neuromuscular scoliosis (NMS) is often associated with rapid progressive spinal deformities. Indications, when to extend the instrumentation to the pelvis for pelvic obliquity are not generally accepted at this time. This study reports on the indications, surgical technique and results using pedicle screw instrumentation exclusively with or without pelvic fixation for spine fusion in patients with NMS. PATIENTS AND METHODS: Thirty-seven NMS patients were treated with pedicle screw instrumentation (PSI) between 2007 and 2013 with a minimum follow-up of 24 months. The mean age at the time of operation was 14.91 ± 2.03 years (range, 11.17-18.58). Posterior spine fusion (PSF) was conducted in 33 patients; 4 patients underwent a combined anterior spinal release followed by PSF during one-stage surgery. Pelvic fixation was achieved by ilium screws combined with S-1 screws in 4 cases and by sacral-alar-iliac (SAI) technique by Sponseller in 9 cases, respectively. RESULTS: The mean primary Cobb angle was 65.5° (range, 14-103°) and improved significantly to 19.8° (range, 1-50°, p < 0.001) after surgery and 20.5° (range, 3-57, p = 0.47) at 2 years FU, respectively. Besides, an improvement of pelvic obliquity and T1 tilt angle could be detected. Major complications occurred in 19% and minor complications in 32%. CONCLUSION: Pedicle screw fixation only for spine fusion in patients with NMS can be applied safely with reasonable complication rates. An excellent correction in all planes, a significant improvement of the pelvic obliquity and almost no loss of correction at 2 years FU were observed.

Serial casting in early onset scoliosis: syndromic scoliosis is no contraindication.

BACKGROUND: Serial casting is a treatment for early onset scoliosis (EOS) in young children to achieve curve correction before bracing or to postpone initial surgical treatment until the patient is older. Good results have been reported for patients with idiopathic early onset scoliosis (IS). However, there are few reports of results in non-idiopathic cases, and the benefits of non-surgical methods in the syndromic-associated early onset scoliosis subgroup are unknown. METHODS: Retrospective single-institution study of patient charts and X-rays of all cases of sustained serial casting for EOS. Staged correction was obtained by applying three consecutive casts under general anaesthesia. These were changed every 4 weeks, followed by the implementation of a custom-made full-time Chêneau brace. Correction was measured by Cobb angle (CA) and rib-vertebra angle difference (RVAD) on whole spine anterior-posterior radiographs. Statistical analysis was performed via ANOVA. RESULTS: The study group consisted of 6 patiens with IS and 10 with non-idiopathic scoliosis (NIS) - exclusively syndromic-associated. The mean age at onset of treatment was 35 months (±15). The mean follow up was 21 months (±15). In IS patients average CA/RVAD before treatment was 46°(±8)/20°(±12). In NIS patients average CA/RVAD before treatment was 55°(±15)/24°(±14). After application of the third cast, the CA/RVAD was reduced to 20°(±11)/11°(±10) in IS patients. Whereas in NIS patients average CA/RVAD after the thrid cast was 28°(±12)/18°(±13). At latest follow-up the CA/RVAD was 16°(±7)/9°(±8) in IS patients and 31°(±11)/17° (±15) in NIS patients. CONCLUSION: Syndromic etiology is not a contraindication for serial casting in EOS. Our results show a curve correction, measured in CA, of 65% in IS patients and 44% in NIS patients. Significant reduction in the morphologic deformity, measured in RVAD, was achieved in the IS cohort, but not in the NIS cohort. In all cases surgical treatment could be delayed.

Incorporation and Remodeling of Structural Allografts in Acetabular Reconstruction: Multiscale, Micro-Morphological Analysis of 13 Pelvic Explants.

BACKGROUND: Total hip arthroplasty (THA) is frequently accompanied by acetabular bone loss, which constitutes a major challenge in revision procedures. Structural allografts can be implanted to restore a stable osseous foundation for the acetabular prosthesis. As previous studies were limited to clinical data or included very few cases, the extent to which the graft bone is incorporated over time has remained unclear. METHODS: Thirteen acetabula were retrieved post mortem, and the incorporation properties of the bone allografts were analyzed using a hierarchical approach of imaging techniques including contact radiography, high-resolution peripheral quantitative computed tomography (HR-pQCT), histological analysis of undecalcified specimens, and quantitative backscattered electron imaging (qBEI). The distance between the current allograft bone and host bone borders (i.e., current overlap) as well as the distance between the original allograft bone and host bone borders (i.e., total ingrowth) were assessed. RESULTS: In 10 of 13 cases, the complete interface (100%) was characterized by direct contact and additional overlap of the allograft bone and host bone, while the remaining 3 cases demonstrated direct contact along 25% to 80% of the interface. The allograft bone showed an intact trabecular structure and significantly higher mineralization compared with the host bone. The mean current overlap (and standard deviation) was 2.3 ± 1.0 mm, with a maximum of 5.3 ± 2.4 mm. Importantly, the total ingrowth reached much further, to a mean of 7.2 ± 2.3 mm (maximum, 10.5 ± 4.0 mm). Neither the time that the allograft was in situ nor the degree of contact between the host and allograft bone correlated with the current overlap and the time in situ did not correlate with total ingrowth. CONCLUSIONS: This study showed bone remodeling with subsequent interconnection of the host and allograft bone along the majority of the interface, leading to adequate incorporation of the allograft. The lack of complete incorporation of the graft did not lead to graft collapse up to 22 years after revision surgery. CLINICAL RELEVANCE: Our study provides the first systematic multiscale evaluation of successfully implanted structural allografts and forms the scientific basis for their clinical use in revision THA.