Cervical H-plate is universally available implant. Being a relatively rigid method of fixation, it ensures fusion more reliably as compared to staples and K-wires, and the spider plate. In our series satisfactory fusion and pain relief was achieved in all the patients. The amount of wrist motion (total arc) obtained (42% of the uninvolved side) and grip strength (more than 70% of the uninvolved side) was acceptable to the patients.
A number of authors have shown satisfactory results of four-corner fusion performed as a salvage of non union scaphoid.4,5,11,12
Our results are comparable to those studies corroborating the fact that, with proper indication, the procedure of four corner fusion gives optimum results.
El-Mowafi et al
. successfully achieved the four-corner fusion by using K wires with further immobilization of the wrist with cast.12
Garcia-López et al
. achieved four-corner fusion by using the screw fixation.13
In order to prevent the collapse of the fused bones, however, they filled the void of the excised scaphoid by using the anchovy of extensor carpi radialis longus tendon.13
Chung et al
used a spider web plate for stabilization and concluded that four-corner fusion using the first-generation Spider plate technique had the advantage of earlier mobility and more patient comfort from absence of protruding Kirschner wires; however, patients continued to have disabling pain, functional limitations, work impairment, and low satisfaction scores postoperatively. Commenting on the failures seen in 3 of the 11 of their patients, they also felt the need for a better implant designed to avoid implant failure. In a comparative study of using traditional implants (K wires, screws and staples) and the circular plate, Vance et al
observed 26% nonunion with loose hardware in the plate group compared with 3% in the traditional group and 22% hardware impingement in the plate group compared with 3% in the traditional group. They concluded that the increased complication and dissatisfaction rates associated with plate fixation was attributable to possible biomechanical imperfections or increased technical demands with the circular plates.
The procedure of four-corner fusion results in loss of motion at the wrist almost to the tune of 50%, which is significant. However, the other options of proximal row carpectomy and total wrist fusion are relatively inferior options as compared to the four corner fusion with the former one having a long term risk of wrist arthritis and the latter one with disadvantage of total loss of motion.2,5
The usual complications of donor site morbidity in case of harvesting of graft from the iliac crest were not seen in any of our patients probably due to a small amount of graft required for the procedure. We feel ‘H’ plate, originally designed for the stabilization of cervical vertebral bodies is able to tolerate significant loads. We did not find any of the problems related to tendon impingement, due to the low profile design of the plate. Further, as per our per- operative observations, the four holes in the four limbs of the ‘H’ have almost exact fit onto the bodies of the four bones constituting four corners (lunate, capitate, hamate, triquetrum). The central hole in the ‘H’ can be additionally used for passing an additional screw into the dowel graft placed in the center of the four corners; however, we have not used it in any of our patients.
All the patients in our series successfully achieved fusion without any failure of the implant. The functional scores seen in all of our patients were also satisfactory, thus implying that ‘H’ plate may prove to be a reasonable alternative to the traditional implants like K wires, screws or spider plate.
The low cost stainless steel indigenously produced ‘H’ plate is likely to make it a favored implant for the surgeons working in developing countries. However, the sample size of our study being small, further larger and controlled multicentric studies are required to know the more detailed results of this technique.