One special use of the plate is in an extensively comminuted neck/shaft fracture of the humerus in which the head fragment can be adequately controlled and the comminution bridged. This usually provides better control of the proximal segment than a nail and can cover longer spans than the locking plates currently available (Figures 1 and 2). It does however require a large incision.
A blade plate can be fashioned from a dynamic compression plate bent at 90 or 95 degrees and inserted into a pre-drilled channel. The blade fixation can be augmented by forming a delta in the articular fragment with a screw angled from the shaft portion of the plate into a hole in the blade portion.
Another type of plate used in the humerus is the paediatric blade plate. A variation on the rigid, fixed angle blade plate has been used in numerous centers and was part of a scientific programme presentation at the American Academy of Orthopaedic Surgeons in 1999 by Dr. D. Kevin Scheid1,2. This device consists of single or stacked seven-hole, semitubular plates bent between 110 and 140 degrees. The fixation can be augmented by a tension band type suture to convert the pull of the rotator cuff into a compression force. It works best in unstable surgical neck fractures with minimal comminution (Figure 3).
Some of the disadvantages of the blade include the fact that it cannot be utilized percutaneously and insertion can be technically demanding.
One of the greatest advantages of its use is that it provides a rigid and fixed angle of fixation which resists varus deformation; the most common mode of failure. This allows early mobilization of the shoulder especially when combined with tension sutures in the rotator cuff. The plate does not violate the rotator cuff, removes no bone, and leaves a relatively small footprint on the proximal humerus.
The development of the proximal humeral locking plate has reduced the use of the blade plate and is technically easier to use. Some disadvantages of the locking plate include the fact that it is expensive, leaves a relatively large footprint on the proximal humerus, and has a limited available length.
In summary, the blade plate in the proximal humerus can be used in various forms: rigid, semi-tubular, and custom made. It has some distinct advantages in select cases when applied with appropriate attention to detail.
References
- D. Kevin Scheid, M.D., Director Orthopaedic Education Methodist Hospital., Orthopaedics Indianapolis. AAOS 1999: Scientific Program Presentation.
- Instrum, K., M.D.: Semitubular Blade Plate Fixation in Proximal Humeral Fractures: A Biomechanical Study in Cadaveric Model., Journal of Shoulder and Elbow Surgery, Vol. 7, #5, September, 1998.
- Jupiter, J.B.; Mullaji, A.B.: Blade Plate Fixation of Proximal Humeral Nonunions., Injury 25: 301-3, 1994.
Figure 1 Comminuted Humeral Fracture.
Figure 2 Healed fracture. (Six months).
Figure 3 Semirigid Blade Fixation.
