Arthrodesis of the Distal Interphalangeal (DIP) Joint of the Right Ring Finger for Arthritis

CHAPTER 1

Distal interphalangeal joint arthritis, or DIP joint arthritis, is second only to thumb basal joint arthritis in terms of the most symptomatic arthritis of the hand often necessitating surgical intervention. The technique being demonstrated here is an arthrodesis of the distal interphalangeal joint. The indication for this technique is pain, deformity, and dysfunction. The technique being demonstrated here is being performed under just local anesthesia in a wide-awake hand surgery fashion.

CHAPTER 2

You'll notice the patient here has advanced arthritic changes of the ring finger DIP joint and has previously undergone index and middle finger DIP arthrodesis. Now the ring finger will be performed today. The technique requires the use of a headless compression screw. Here a 2.4 headless compression screw will be used.

Because the anesthesia being used is only a digital block with minimal lidocaine and epinephrine in the surgical site directly, a finger tourniquet is also being applied.

CHAPTER 3

The exposure is achieved entirely dorsally, so the incision is placed directly across the DIP joint dorsally. The incision is placed full thickness through the skin, tendon, and the dorsal joint capsule.

CHAPTER 4

The joint is then opened, and the collaterals are also taken down to fully expose the joint. Care is taken not to injure the flexor tendon deep to the joint on the volar side.

CHAPTER 5

With the DIP joint fully exposed and the articular surface of the middle phalanx's head and the distal phalanx space exposed, a rongeur is used to debride off the articular cartilage down to subchondral bone. I find it as easier to debride the middle phalanx's head first before progressing to the distal phalanx space, because once the middle phalanx has been debrided the distal phalanx space is better exposed. Generally, that distal side is harder to debride of articular cartilage. It is often helpful to elevate the soft tissue off of the dorsum of the distal phalanx space as shown here, even extending the flap distally around the nail may also be helpful to fully expose the base to get the articular cartilage off.

CHAPTER 6

Once debrided, the fluoroscopy machine can be brought in to confirm adequate debridement down to subchondral bone as well as to make sure adequate alignment has been restored and any deformity corrected. This should be checked on both the PA and lateral views. Extra osteophytes that have been left behind can also be assessed now and debrided away.

CHAPTER 7

Once satisfied with the joint debridement and alignment of the arthrodesis site, the guidewire for the headless compression screw is prepared to be inserted. I recommend using an inside-out technique where the guidewire is first placed across the distal phalanx in the desired center, center position and then reversed into the middle phalanx. The inside-out technique is being shown here. Once happy with the alignment of the guidewire, that guidewire is then removed, flipped around, so that the blunt end is then directed into the distal phalanx until only a bit of the sharp end is showing within the arthrodesis site. This will then allow the sharp end to be then placed retrograde into the middle phalanx under direct visualization. Here, reversal of the pin and alignment of the arthrodesis site is demonstrated on fluoroscopy. Once satisfied with the alignment, the pin can then be advanced into the middle phalanx. Here the pin can be seen being advanced retrograde back into middle phalanx and then confirmed on fluoroscopy.

CHAPTER 8

Next, the screw length is measured. I generally find the available cannulated depth gauges to be unhelpful, because the length of the screws should be such that it is countersunk below the head of the distal phalanx and should end within the isthmus of the middle phalanx. So oftentimes, what is more helpful is simply measuring a screw on fluoroscopy to fit that desired length.

CHAPTER 9

Next, the cannulated drill is placed across the guidewire to create the path for the headless compression screw, and finally, the screw is placed across the guidewire and advance into the distal phalanx in a retrograde fashion. To achieve maximal compression across the arthrodesis site, I recommend compressing the arthrodesis site externally to achieve what I refer to as macro-compression and then allow the headless compression screw to achieve a micro-compression.

CHAPTER 10

Here, final position of the screw is confirmed making sure that the screw head is adequately countersunk within the distal phalanx, and that there is good contact and compression without gapping across the arthrodesis site. Also, prior to washing the wound and closure, restoration of normal rotation of the finger should also be confirmed with active flexion of the finger by the patient to make sure that the alignment is appropriate.

CHAPTER 11

If there is excessive redundancy of the skin, the proximal aspect of the skin can be excised to improve the closure. Also, I find it helpful to repair the skin in a tenodermodesis technique. That involves repairing the skin and the underlying extensor tendon in one throw. That helps bulk up the closure dorsally and cover the arthrodesis site. I use simple 4-0 nylon sutures as demonstrated here. Once closed, a soft dressing is applied. The patient is allowed to move the finger immediately. Obviously, the the DIP joint will not move, but early motion overall is encouraged. The dressing can be removed in two days, and the sutures can be removed in two weeks.

CHAPTER 12

I typically check radiographs again at two weeks and 12 weeks postoperatively to confirm healing of the arthrodesis site. The patient is allowed to return to activities as tolerated immediately. The last thing to discuss is a word of warning. Sometimes fingers can be larger, and a larger screw can be used. In this case, a 2.4 screw was used. More commonly and more troublesome is that some fingers are smaller and have difficulty accepting a headless screw. I would refer you to a study published by one of our former fellows who looked at the diameter of screws and found that some fingers require smaller screws such as closer to 2.0 to meet the diameter of the canal of the distal phalanx and middle phalanx.