Surgical Management of Skier's Thumb
To you it's a sprained thumb. To the hand surgeon, it's an injury of the ulnar collateral ligament of the metacarpophalangeal joint of the thumb. In the old days it was called a gamekeeper's thumb. Today, it's more likely to be a sports injury, sometimes referred to as skier's thumb. Jamming the web of the thumb into the ski pole tears the ulnar collateral ligament (UCL). It's a common problem that orthopedic surgeons and primary care physicians deal with routinely.
This review article will bring us all up-to-date on the anatomy, mechanism of injury, diagnosis, and treatment of this injury. Rupture of the ligament away from the bone usually means the ligament won't heal without surgery. So a careful examination and accurate diagnosis is important before a plan of care can be established.
The ulnar collateral ligament of the thumb is a strong band of tissue attached to the middle joint of the thumb, the joint next to the web space of the thumb. The joint that is affected is called the metacarpophalangeal joint, or MCP joint.
Any hard force on the thumb that pulls the thumb away from the palm of the hand (called a valgus force) can cause damage to the ulnar collateral ligament. The most common way for this to happen is to fall on your hand with your thumb stretched out. If the force is too strong, the ligaments can tear. They may even tear completely. A complete tear is also called a rupture.
When the collateral ligaments actually tear, the MCP joint becomes very unstable. It is especially unstable when the thumb is bent back. If one of the ligaments pulls away from the bone and folds backwards, it won't be able to heal in the correct position. When this happens, surgery is needed to fix the ligament.
After taking a patient history, the physician checks the patient's thumb range-of-motion. This is a telltale sign because too much motion can be an indication of joint instability. But further testing is needed to identify whether the muscles, tendons, ligaments, and/or joint capsule are involved. With a severe enough trauma, the ligament can pull away a small piece of bone with it when it ruptures. Such an injury is called an avulsion fracture.
Any palpable or visible deformities should be noted. X-rays help reveal any fractures. Stress testing is done by placing the thumb in various positions and having the patient try to hold it there while the examiner pushes against the thumb trying to move it. The role of other advanced imaging studies such as MRIs, arthrography, or ultrasound has been debated. These are not always accurate enough to warrant the cost.
Partial tears can be treated nonoperatively with conservative care. Complete ruptures of the ulnar collateral ligament often require surgical repair. The surgery can be done on an outpatient basis under a regional or general anesthesia. The authors provide a step-by-step description of the surgical repair from incision to restoration of the anatomy.
Sometimes the ligament can be repaired by reattaching it to the bone. Small avulsion fractures can also be repaired this way with special sutures used to anchor the bone fragment in place. Any damage to the other soft tissues or joint capsule can be repaired at the same time. If the damage is too great to repair the problem, then a tendon graft may be needed to reconstruct the joint. No matter whether it's a surgical repair or reconstruction, the goal is to return everything to as normal an anatomical orientation as possible. This will ensure a return of normal joint kinematics (movement).
The patient is put in a cast and immobilized for six weeks after surgery. When the cast is taken off, the pins and wires holding everything together can be removed. A hand therapist helps the patient get started with range-of-motion exercises. The therapist progresses the rehab program through strengthening and return to full activities without restrictions. All of this takes at least three months for a safe and effective result.
Studies show that this approach is quite successful. The earlier the repair is made, the better the results. Returning to activities when the thumb is unstable can cause further damage that could have been avoided with early diagnosis and treatment. Ninety per cent of the time, the results are good-to-excellent with surgical repair.
In a small number of cases problems can occur following surgery such as a nerve palsy affecting motion, joint stiffness, and chronic instability. There is some evidence that these poor results are more likely when treatment was delayed or the diagnosis was missed. Studies to determine the best surgical technique to use for optimal outcomes are underway.
When the surgery is unsuccessful and joint instability persists, it may be necessary to fuse the joint. This procedure is called an arthrodesis. Arthrodesis works well for patients who have developed post-traumatic arthritis. But the hope is to avoid such long-term complications with early and appropriate intervention.
Michael A. Baskies, MD, and Steve K. Lee, MD. Evaluation and Treatment of Injuries of the Ulnar Collateral Ligament of the Thumb Metacarpophalangeal Joint. In Bulletin of the NYU Hospital for Joint Diseases. March 2009. Vol. 67. No. 1. Pp. 68-74.
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