Purpose: Since 1966 silicone implant arthroplasty has been used to treat arthritis of the PIP joint as an alternative to fusion. The volar approach to expose this joint spares the extensor mechanism at the cost of increased risk to neurovascular structures. In the dorsal approach, the extensor mechanism must be carefully handled, reattached and then protected during rehabilitation. Several surgical techniques have been used to handle the extensor mechanism. Swanson et al. recommended midline incision of the central tendon followed by release of the lateral insertion on the middle phalanx and then reattachment to the base of the middle phalanx. Our clinical experience led us to a new surgical technique; splitting then repairing the extensor mechanism without bone reattachment as recommended by Swanson. The purpose of this study was to biomechanically compare the strength and function of this proposed technique with that of Swanson.

Method: Four pairs of fresh-frozen cadaveric hands were used. The index, long and ring finger were harvested for testing. Twelve digits (3 digits × 4 hands) were designated as control and were used to measure the fixation strength of Swanson’s procedure. The other 12 digits of the paired hands were designated as experimental and were used to measure the fixation strength of the proposed new technique.

Results: The fixation strength mean ± SD were, respectively, 4.74 ± 0.46 N/mm for the control group and 4.62 ± 0.30 for the experimental group. The results were not statistically different, p=0.45.

Conclusion: The simple repair of the central slip without the bone reattachment preserves the function of the extensor mechanism on the PIP joint. In our clinical cases we haven’t noticed any increase in the incidence of extensor lag or boutonnière deformity as a result of that. This technique can also be applied for fracture fixation in the area.