Various surgical techniques have been devised for four- corner fusion. Previously, four-corner arthrodesis has been attempted using staples or K-wires for fixation, but a less reliable fixation sometimes resulted in risk of failure of fusion.⁷ More recently, implants such as spider plate and differential pitch cannulated screws have been used to achieve rigid fixation, with variable results.^8,9 In a recent study, a high rate of non-union was reported using the spider plate, with fusion being achieved in only 16.67% of the cases.⁹

The average time between injury and presentation was 3.27 years (1.2 to 4.82 years). The average duration of follow-up was 5.8 years (range 2.8 years-10 years) [Table 1].

Each patient was evaluated clinically pre-operatively and assigned a ‘pain rating’ and ‘activity rating’, as per the rating scale described by Bach¹⁰ [Table 2].

The mean grip-strength calculated as a percentage of the uninvolved side was 47% pre-operatively, and 74% postoperatively at final follow-up.

The pre-operative and postoperative Bach scores for the study population are listed in Table 4, with the mean pre-operative pain rating being 5.66, and the mean postoperative pain rating being 2.16. The mean preoperative activity rating was 5, while the mean postoperative activity rating was 2.2.

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.⁸ 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.¹⁴ 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.