RESUMO
BACKGROUND: The incidence of radial head fractures is increasing, and radial head arthroplasty (RHA) is being more frequently utilized as treatment for irreparable fractures. Our objective was to compare radiocapitellar pressure between the native joint and two radial head prosthesis conditions - (1) a prosthetic head that was aligned to the forearm axis of rotation and (2) the same prosthesis with an axisymmetric nonaligned head. METHODS: Ten cadaveric specimens received a pressfit radial head prosthesis (Align, Skeletal Dynamics, Miami, FL) for both prosthetic testing conditions. Anatomic alignment (AL) was defined as the prosthetic head aligned to the forearm axis of rotation. Axisymmetric alignment (NA) was defined as the prosthetic radial head aligned to the axis of the prosthetic stem. Axial load was applied with the elbow in extension and the forearm pronated. Data was collected using a Tekscan 4000 sensor. RESULTS: The mean pressure in the AL and AX groups were significantly higher than the mean pressure in the native joint. Compared to the native joint, the mean pressure was 19% higher in the AL group and 56% higher in the AX group. Peak pressure beyond 5 MPa occurred in zero specimens in the native joint group, in one specimen (10%) in the AL group, and in five specimens (50%) in the AX group. DISCUSSION: Our results demonstrated that a pressfit radial head prosthesis aligned with the forearm axis of rotation yields capitellar pressures that were more similar to the native condition than a non-aligned pressfit prosthesis. These findings suggest that anatomic alignment may optimize capitellar wear properties, improving the long-term durability of radial head arthroplasty.
RESUMO
Aim: The aim of the study is to demonstrate the safety and efficacy of the use of magnetically controlled intramedullary nails in patient with programmable implantable devices. Background: Magnetically driven intramedullary limb lengthening devices have revolutionised the field of limb reconstruction. Because the system is powered by strong magnets, there are warnings to avoid the use of the device in patients with implanted programmable devices, such as cardiac pacemakers. Materials and methods: Four patients with three different types of programmable implanted devices presented to two centres for limb lengthening and limb reconstruction. Each patient had a limb length discrepancy and desired correction using an intramedullary lengthening device. After thorough counselling about the potential risks and benefits of the procedure as well as discussions with each patient's medical team, the decision to proceed with surgery was made. Results: All four patients underwent osteoplasty with insertion of a magnetically driven intramedullary lengthening nail. Goal length was achieved with successful consolidation and subsequent nail removal in all patients. There were no malfunctions of the implantable devices during the distraction phase in any of the patients. Conclusion: With proper precautions, intramedullary lengthening can be performed safely and successfully using a magnetically driven nail in patients with previously implanted programmable devices. Clinical significance: This initial experience suggests use of magnetically controlled intramedullary nails in patient with programmable implantable devices can be undertaken safely within constraints of precautions. How to cite this article: Iobst CA, Hatfield DN, Forro SD, et al. Magnetically Driven Intramedullary Limb Lengthening in Patients with Pre-existing Implanted Programmable Devices: A Case Series. Strategies Trauma Limb Reconstr 2023;18(2):111-116.
