Safety of orthopedic implants in magnetic resonance imaging: an experimental verification.

Magnetic resonance imaging (MRI) is an indispensable tool for musculoskeletal imaging. The presence of metal, however, raises concerns. The potential risks are loosening and migration of the implant, heating of the metal with surrounding tissue, causing thermal damage, and artifactual distortion which compromise the diagnostic value of the procedure. The aim of this study was to test experimentally the nature and extent of the first two of these effects in orthopedic implants. The degree of ferromagnetism was evaluated by deflection studies at the portals of a 0.25 Tesla permanent magnet and 1.0 Tesla clinical MRI scanner. None of the orthopedic implants exhibited any attraction. External fixator clamps, however, showed significant ferromagnetism. The heating of implants by "worst-case" scenario imaging sequences was insignificant. Many contemporary nonferromagnetic orthopedic implants can be imaged safely. It is prudent, however, to perform ex vivo deflection studies on a duplicate implant to confirm MR compatibility. With external fixator devices exhibiting strong ferromagnetism, MRI should be avoided. With expanding indications for MRI, orthopedic implants are unlikely to limit the potential of this powerful tool.

Surgical management of the severely displaced supracondylar fracture of the humerus in children.

We reviewed 44 children with a widely displaced supracondylar fracture of the humerus (Gartland grade III) treated with primary open reduction and cross pinning. The average age was 8 years and the mean delay in presentation was 34 h. Comminution of the medial supracondylar pillar was seen in 57% of the cases. After treatment, the range of the elbow motion was restricted in eight patients. Cubitus varus was not seen. There was no deep infection or myositis ossificans. Post-operatively, five children had a temporary nerve palsy. According to Flynns' criteria, 42 patients had a satisfactory outcome.

A study of vascular injuries in pediatric supracondylar humeral fractures.

194 children with supracondylar fractures of the humerus were reviewed. Of the 49 children with Gartland grade III displacement, signs of vascular compromise were clinically suspected in 5 cases. Immediate open reduction, internal fixation and exploration were performed. Four children had a satisfactory outcome. One child required amputation. A careful clinical evaluation for vascular injury and an aggressive surgical approach is suggested, when indicated.

The Hoffa fracture: Three case reports.

Unicondylar fractures of the lower end of the femur are uncommon injuries that usually occur in the saggital plane 2. Coronal (tangential) plane fractures, first described by Hoffa in 1904, are unusual.(1,2, 3,4) We report our experience with three cases and the mechanism of injury is discussed. Open reduction and internal fixation is mandatory for good long-term results.

Medial approach for operative treatment of the widely displaced supracondylar fractures of the humerus in childre.

Twenty-seven widely displaced supracondylar fractures of the humerus in children were treated by open reduction and cross K-wire fixation by the medial approach over a 30-month period. The mean follow-up was 14 months, average age 8 years and the mean delay in presentation 49 hours. Medial approach provided an excellent view of the medial bone pathology via an internervous plane and enabled an anatomical reduction in all cases. Cross K-wire fixation obviated the need to immobilize the elbow at 90 degrees or more flexion. No postoperative neurovascular complication was noted. Most patients regained full range of motion within 6 weeks of pin removal and no change in the carrying angle was noted. Delayed presentation, repeated manipulations and massage were responsible for loss of motion. Superficial pin tract infection was noted in 5 patients and resolved with dressings and antibiotics. No deep infection occurred. Medial approach for open reduction and internal fixation of the widely-displaced supracondylar fracture of the humerus is safe and straightforward, ensuring anatomical reduction and excellent function.