Transfixation of the DIP joint can be used for internal splinting of bony and fully ligamentous dorsal avulsions.
It is an easier alternative to extensor block pinning.
Operative treatment: caveat
Inexperienced handling of this area may harm the germinative matrix of the nail and cause permanent deformity. Consider that nonoperative treatment is almost always a viable alternative in these fractures, often with comparable results. Operative treatment should only be attempted by experienced hand surgeons in selected cases.
Indications for surgical intervention are:
Palmar subluxation of the DIP joint
Surgical management of these fractures is difficult and has many potential complications. The soft tissues are only precariously vascularized, and the fragments are very small and prone to further comminution. Healing can often be slow.
Potential risks of percutaneous pinning
The commonest risk of percutaneous K-wire immobilization is infection.
Breakage of the K-wire at the level of the DIP joint can be avoided by using a wire of 1.6 or 1.8 mm diameter and counseling the patient to avoid stresses at the DIP joint.
To avoid unnecessary radiation from image intensification, mark the planned track of the K-wire on the distal phalanx in both the AP and the lateral aspects.
Insert the K-wire through the tip of the distal phalanx up to the DIP.
Carefully reduce the fracture by extending the DIP joint and shifting the distal fragment.
The K-wire may be used as a reduction tool.
Confirm DIP joint reduction with an image intensifier in the lateral view.
5. Joint transfixation
Advance the K-wire across the DIP joint into the middle phalanx as far as its base. Be careful not to penetrate the PIP joint.
Cutting the K-wire
Cut the K-wire so that it protrudes through the skin. Bend its end to form an L-configuration to prevent catching on clothing, etc. The tip of the bent wire can be rotated towards the ulnar side to avoid interfering with pinch grip, which involves the radial side of the pulp.
Leaving the K-wire to protrude through the skin in this way has the advantage of its being easy to remove. The disadvantages are patient discomfort and risk of pin-track infection.
Make sure that the bent end does not irritate or compress the skin.
Usually, immobilization is not necessary.
Sometimes, a splint leaving the PIP joint mobile may be an option.
Hand therapy is recommended to prevent soft-tissue atrophy and joint contracture (typically extension of MCP joint and flexion of PIP joint), which leads to a poor outcome, and subsequent treatment is difficult.
Functional exercises of the nonimmobilized joints should be started immediately to keep uninjured joints mobile.
Active motion of the DIP joint is permitted after removal of the K-wire. Passive motion should be postponed for 8–10 weeks to avoid the risk of recurrent mallet deformity.
Depending on the injury, the K-wire may be removed, usually after 4–6 weeks for bony injuries and after 6–8 for purely tendinous injuries.
At this stage, X-rays should be taken to confirm healing.