The Performance of MAGEC X Spine Rods: A Comparative Retrieval Study

Study Design: Multicentre comparative analysis of explanted Spine Magnetically Controlled Growing Rods (MCGRs). Objectives: MAGEC X, the latest commercially available generation, was recalled in 2020 due to the risk of post-implantation separation of an actuator end-cap component. Currently, the supply of all MAGEC rods was temporarily suspended in the UK and the EU. Objective of this study is to compare the performance of the MAGEC X MCGR to the earlier MAGEC 1.3 design iteration, by means of retrieval analysis. Methods: Fifteen of both MAGEC X and MAGEC 1.3 rods were consecutively collected from five different hospitals following removal surgery and matched by time to removal. Clinical and implant data was collected for all MCGRs. Analysis comprised visual assessments of external damage, plain radiograph evaluations, force and elongation testing, MAGEC X end-cap torque testing and disassembly. Mann-Whitney U tests were used to statistically compare groups. Results: Rod distraction reached in vivo was significantly higher in the MAGEC 1.3 (P =.002). There was no statistically significant difference in the total external damage score (P =.870), maximum force produced (P =.695) or distraction reached during force test (P =.880). No pin fracture was detected. Elongation of stroke was mildly higher (P =.051) for the MAGEC X implants. One MAGEC X had evident end cap component loosening. Internal damage scores were mildly lower in the MAGEC X group. Conclusion: MAGEC X showed similar performance results than the previous design iteration MAGEC 1.3. End-cap component loosening was observed, with no major consequences on the internal mechanism

Blood titanium levels in patients with large and sliding titanium implants

Background: Titanium, which is known to be a highly biologically inert element, is one of the most commonly used metals in orthopaedic implants. While cobalt and chromium blood metal ion testing is routinely used in the clinical monitoring of patients with metal-on-metal hip implants, much less is known about the levels of titanium in patients with other implant types. The aim of this study was to better understand the normal ranges of blood titanium levels in patients implanted with large and sliding titanium constructs by comparison with reference levels from conventional titanium hips. Methods: This study examined data collected from 136 patients. Over a period of 24 months, whole blood samples were collected from 41 patients implanted with large titanium implants: long (range 15 to 30 cm) spine rods with a sliding mechanism (“spine rods”, n = 18), long bone tumour implants (“tumour implants”, n = 13) and 3D-printed customised massive acetabular defect implants (“massive acetabular implants”, n = 10). This data was compared with standard, uncemented primary titanium hip implants (“standard hips”, 15 cm long) (n = 95). Clinical, imaging and blood titanium levels data were collected for all patients and compared statistically between the different groups. Results: The median (range) of blood titanium levels of the standard hip, spine rods, femoral tumour implants and massive acetabular implants were 1.2 ppb (0.6–4.9), 9.7 ppb (4.0–25.4), 2.6 ppb (0.4–104.4) and 5.7 ppb (1.6–31.5) respectively. Spine rods and massive acetabular implants had significantly greater blood titanium levels compared to the standard hips group (p < 0.001). Conclusion: This study showed that titanium orthopaedic implants that are large and/or have a sliding mechanism have higher blood titanium levels compared to well-functioning, conventionally sized titanium hips. Reassuringly, the increased levels did not appear to induce adverse metal reactions. This study provides useful baseline data for future studies aimed at assessing blood titanium levels as a biomarker for implant function

Pin Fracture in Magnetically Controlled Growing Rods: Influence of the Year of Manufacture

Permissions ORIGINAL ARTICLE Pin Fracture in Magnetically Controlled Growing Rods: Influence of the Year of Manufacture Tognini, Martina BEng, MSc*; Hothi, Harry BEng, MSc, PhD†,‡; Dal Gal, Elisabetta MSc*; Henckel, Johann MBBS, MRCS, PhD‡; Shafafy, Masood MBBS, FRCS, FRCS§; Broomfield, Edel MSc∥; Tucker, Stewart MBBS, FRCS, FRCS∥; Skinner, John MBBS, FRCS, FRCS*,‡; Hart, Alister MA, MD, FRCS*,‡ Author Information Journal of Pediatric Orthopaedics ():10.1097/BPO.0000000000002460, June 19, 2023. | DOI: 10.1097/BPO.0000000000002460 OPEN PAP Metrics Abstract Background: Magnetically controlled growing rods (MCGRs) have a known issue with fracture of the internal locking pin resulting in early revisions. The manufacturer reported that rods manufactured before March 26, 2015, had a 5% risk of locking pin fracture. Locking pins made after this date are thicker in diameter and of a tougher alloy; their rate of pin fracture is not known. The aim of this study was to better understand the impact of the design changes on the performance of MCGRs. Methods: This study involves 46 patients with 76 removed MCGRs. Forty-six rods were manufactured before March 26, 2015, and 30 rods after that date. Clinical and implant data were collected for all MCGRs. Retrieval analysis comprised plain radiographs evaluations, force and elongation testing, and disassembly. Results: The 2 patient groups were statistically comparable. We found that 14 of 27 patients implanted with rods manufactured before March 26, 2015 (group I) had a fracture of their locking pins. Three of the 17 patients with rods manufactured after this date (group II) were also found to have a fractured pin. Conclusions: Retrieved rods collected at our center and made after March 26, 2015, had far fewer locking pin fractures than those made before this date; this may be due to the change in pin design

Bracing Adolescent Idiopathic Scoliosis (BASIS) study - night-time versus full-time bracing in adolescent idiopathic scoliosis: study protocol for a multicentre, randomized controlled trial.

AimsScoliosis is a lateral curvature of the spine with associated rotation, often causing distress due to appearance. For some curves, there is good evidence to support the use of a spinal brace, worn for 20 to 24 hours a day to minimize the curve, making it as straight as possible during growth, preventing progression. Compliance can be poor due to appearance and comfort. A night-time brace, worn for eight to 12 hours, can achieve higher levels of curve correction while patients are supine, and could be preferable for patients, but evidence of efficacy is limited. This is the protocol for a randomized controlled trial of 'full-time bracing' versus 'night-time bracing' in adolescent idiopathic scoliosis (AIS).MethodsUK paediatric spine clinics will recruit 780 participants aged ten to 15 years-old with AIS, Risser stage 0, 1, or 2, and curve size (Cobb angle) 20° to 40° with apex at or below T7. Patients are randomly allocated 1:1, to either full-time or night-time bracing. A qualitative sub-study will explore communication and experiences of families in terms of bracing and research. Patient and Public Involvement & Engagement informed study design and will assist with aspects of trial delivery and dissemination.DiscussionThe primary outcome is 'treatment failure' (Cobb angle progression to 50° or more before skeletal maturity); skeletal maturity is at Risser stage 4 in females and 5 in males, or 'treatment success' (Cobb angle less than 50° at skeletal maturity). The comparison is on a non-inferiority basis (non-inferiority margin 11%). Participants are followed up every six months while in brace, and at one and two years after skeletal maturity. Secondary outcomes include the Scoliosis Research Society 22 questionnaire and measures of quality of life, psychological effects of bracing, adherence, anxiety and depression, sleep, satisfaction, and educational attainment. All data will be collected through the British Spine Registry