Mallet Finger Injury

“my finger doesn’t work”
“my finger is bent”
“my finger won’t straighten”
“my finger is drooped”
These are several of the most common things I hear when patients come in with a mallet finger.
A mallet finger is the name for a ruptured (torn) tendon at the tip of the finger. A tendon rupture is where a tendon rips off the bone where it’s normally attached.
This can happen by jamming the finger, by cutting the tendon on top of the finger, or even with a lot of pressure on the fingertip, like if you’re trying to rub paint out of the carpet.
It usually happens in people over 40 years old. Sometimes these injuries hurt, but not too bad at all. That’s why lots of people come into my office several weeks after the injury.
Some mallet fingers cause a huge droop – 45 degrees or more. Others are more subtle and minor; just a small droop. But in every case, the patient can’t extend (straighten) the end joint of the finger.
The extensor tendon normally attaches to the dorsal (top) side of the finger. When your extensor muscle fires, it pulls the tendon, which pulls the bone up into extension.

Your flexor tendon attaches on the volar (bottom) side of the fingertip, and is about 6 times stronger than the extensor on top, so the finger rests in flexion (bent) without the extensor on top to hold it straight.

The extensor tendon isn’t like a solid piece of rubber or plastic that just completely snaps in half every time. It’s made of millions of tiny strands of collagen, kind of like the strands of a rope or a mop. These strands can pull apart completely, partially, or on one side of the tendon or the other.
Splinting
When the tendon tears off the bone, the bone at the end of the finger – the distal phalanx – droops down. If the tendon fibers are to heal, the torn ends need to be brought back closer together. In a mallet finger, we do this by splinting the end joint (DIP joint) straight.
Splinting is the least risky, most effective treatment option for these injuries. The best splints are made by a hand therapist out of thin, moldable plastic.
But even more important than the splint material is the fact that the splint MUST be worn full time. If you remove the splint and let the finger droop ONE TIME, all the healing is torn apart, and you have to start over.
The therapist can teach you some tricks of wearing the splint, but it’s safer not to remove the splint for a full SIX WEEKS.
Even when you do what you’re supposed to do and the splint is made perfectly, EVERY mallet finger injury heals with a slight droop. It may be three degrees or 10 degrees, but it won’t be completely normally straight at the end of the process.
Even surgery doesn’t make this better. Even if I put a pin inside the finger to hold it straight, you’ll still have a droop.
There are some surgeries that can be done for mallet fingers that stay VERY drooped after six or eight weeks, but none of them are very predictable, and all have more risk than the average carpal tunnel or routine hand surgery.
Another reason the splint doesn’t work well is if the constant splinting is started late – a week or more after the injury. There’s just too much scar tissue formed between the ends of the tendon for it to heal correctly.
Setting up your phone for a telemedicine visit
In this video, I’ll show you how to simply set up your phone for a telemedicine visit. Click the Play button in the middle of the video to start watching!
If the video is too small – click the full screen button in the lower right corner of the video.
Surgery For Wrist Arthritis
The most common type of wrist arthritis creates pain at the thumb, or radial side of the wrist. Pain can flare up and down, with good days and bad days. Sometimes a wrist brace, anti-inflammatory pills, heat or ice can help. Hand surgeons can help with occasional cortisone (steroid) shots in the joint.
When all these treatments fail (or when you’re just sick of them), surgery is a good option. All these other treatments just deal with the symptoms.
Surgery is the only way to get rid of the arthritis forever.
Two surgeries exist for wrist arthritis: proximal row carpectomy (PRC) and partial wrist fusion, also known as four corner wrist fusion.
Both surgeries stop the arthritis pain because the worst and most painful carpal bone, the scaphoid, is completely removed. Unfortunately, just taking out this bone isn’t good enough. Something else has to be done to prevent the rest of the wrist from becoming arthritic.
In the PRC procedure, the scaphoid, lunate, and triquetrum bones are removed. These three bones form the “proximal carpal row”, basically a row of three bones close to the radius and ulna (where the forearm bones join with the tiny wrist bones).

This leaves a big space, obviously, but it’s filled in as the distal row of carpal bones sinks into the space, forming a new joint. This surgery takes about six weeks to recover from. You’re in a temporary splint for 10 days, then into a cast for 3 weeks. Then you start some gentle motion and maybe visit the hand therapist a few times.
In the partial wrist fusion surgery, after the scaphoid bone is removed, instead of taking out more bones, I fuse together four of the remaining carpal bones: the lunate, triquetrum, capitate, and hamate. A fusion means forcing the bones to grow together into a solid, stable mass of bone.

A wrist fusion requires hardware – this could be anything from simple stainless steel wires to special staples, to a small plate and screws. Most of the time I use a plate and screws. The fused bones take about six weeks to heal solid. During that time, you’re in a cast with your fingers free, but can’t lift or grip anything. You may need some therapy afterwards to get the wrist moving again.
A “total” wrist fusion means the wrist never bends again. That’s different than the “partial” wrist fusion I’m talking about here.
Deciding which is best
PRC versus partial wrist fusion is controversial. Most of the research that tries to study which one is better tells us that they’re equal. Both are pretty good at stopping pain. Both options let patients function very well after surgery.
My advice is to have the least complicated surgery that stops the pain. For most people, that’s a PRC. No hardware to worry about; no fusion to heal, and a slightly faster recovery time.
The advantage of a partial wrist fusion is mostly theoretical, in my opinion. It leaves more of your natural anatomy in place than a PRC. But with higher risk of complication (the fusion not healing or having to take hardware out later). Some surgeons believe that a PRC weakens the grip, but there’s no good science to tell us that for sure.
Surgery For Thumb Arthritis
Many operations have been designed over the last 100 years to treat this type of arthritis. They all have one thing in common: removing a bone called the trapezium, which is covered with arthritis.
LRTI Surgery
Taking out the trapezium leaves a hole, an empty space with bones, tendon, and muscle all around it. Most of the videos on YouTube show the surgeon taking a tendon from the forearm (usually the FCR – flexor carpi radialis), rolling it up, and putting it in this space to form a cushion for the remaining bones. This is commonly known as an “LRTI” thumb surgery, which stands for ligament reconstruction tendon interposition.
I used to do this operation as well, but after a few years found a simpler way to accomplish the same thing, save the FCR tendon, and with lower risk of complications for patients.
In the current version of this surgery, which I’ve used since about 2011, I only work through the original incision. No extra tendon is harvested or rolled up.
Steps of the Operation
In this drawing, I show the internal anatomy of the thumb from a side view – as if you just rested the back of your left hand on the table in front of you and looked at the thumb from the side, pointing your fingers to your right.
The thumb has three bones. Naming them from the tip toward the wrist, they’re called distal phalanx, proximal phalanx, and metacarpal.
The metacarpal base joins up with the trapezium – that’s where the worst thumb arthritis is in most people. This is where most people see a big bony lump at the base of their thumb. The next bone back towards the wrist is the scaphoid (skay-foid) bone.
I make the incision directly over the trapezium bone, on the top side of the thumb. When I take out the trapezium, as mentioned above, the space that’s left is between the thumb metacarpal bone and the scaphoid bone.
Visualize the space as a room with a ceiling and floor. Strung across the ceiling, or top of the incision (top of the thumb) is a large tendon called the APL (abductor pollicis longus). Deep in the “floor” of the space (toward the palm side of your thumb) is another large tendon called the FCR (mentioned above – same one).
The next step in the surgery is to “pinch” those two tendons closer together with a strong suture. This forms a cushion where the metacarpal can glide smoothly when everything is healed up. It also pulls the base of the metacarpal down from its “kicked up” position (reducing the big bony lump most people have).
This is the part that has to heal for a solid four weeks after the surgery. That’s why you can’t use your thumb for a month afterwards.
Recovery From Thumb Arthritis Surgery
The surgery takes about 45 minutes from start to finish. Afterwards you’re in a bulky, well-padded dressing and splint from the tip of the thumb all the way up the forearm for ten days. Your elbow and all other fingers are free.
After ten days, you come back to the office and get sutures out, then you’re fitted for a custom thumb splint, which will protect the surgery for another two and a half weeks. Then you’ll finally start getting the thumb loosened up by doing therapy exercises – mostly at home.
Most patients are pinching and gripping by three months on average. Some move faster, some move slower. You should be free of the splint by six weeks after surgery.
For a detailed description of the recovery process and how to prepare for it, click here. This was written by one of my patients who thoughtfully took notes on her experience.
On The Beach – March 2017
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