Thumb UCL injury Info
Last reviewed
What you're feeling
You will likely feel pain right at the base of your thumb where it meets your hand. This pain comes from the ulnar collateral ligament, a key band of tissue that keeps your thumb stable. As the ligament tears, the joint becomes progressively unstable. You might notice that simple movements feel loose or wobbly.
Daily tasks can become difficult or painful. Reaching behind your back to fasten a bra may hurt. Tucking in a shirt or lifting a heavy object can trigger sharp discomfort. The pain often flares up after you use your hand or at night when you try to sleep on your side. You may find that gripping things feels weak or awkward.
Your surgeon will check these symptoms carefully. If you have a displaced fleck sign on an X-ray, it suggests the ligament is trapped in a way that often requires surgery. While you wait for treatment, a thumb spica cast may protect the area. This helps the ligament heal but can sometimes stress nearby joints. Most people see their pain and function improve significantly three months after repair, with continued gains by twelve months.
What's actually happening
When you injure your thumb, the ulnar collateral ligament tears in a sequence. This ligament is a strong rope of tendon fibres that holds your thumb joint together. As these fibres tear, the joint loses its stability and begins to wobble. This progressive instability is what causes the pain and weakness you feel.
The joint itself is protected by a sleeve called the joint capsule. In some cases, a piece of bone may pull away with the ligament, creating a small fragment. If this fragment is displaced, it can get trapped in the joint, acting like a stone in a gear. This specific blockage often requires surgery to fix. While the shape of your thumb bone does not cause the tear, the surrounding muscles play a role. If your forearm muscles do not contract strongly enough, they place extra stress on this ligament, making it more likely to give way.
Your surgeon may repair this rope using a special tape or replace it with a tendon graft from your own body. These methods help restore the normal movement of your thumb without making the joint too stiff. Even with treatment, no repair using your own tissue matches the original strength of the ligament perfectly. However, most patients see their pain and function improve significantly at three and 12 months after surgery.
What we can do about it
You can start by protecting your thumb and working with a physiotherapist. A thumb spica cast or a stabilizing brace helps keep your joint from moving too much while it heals. This approach aims to reduce pain and improve how your thumb feels and functions. You may need to give this non-surgical care several months to see if it works. Some patients find that individual muscle contractions in their fingers help stabilize the joint during this time.
Your surgeon may suggest pain medication or anti-inflammatories to manage discomfort. While the evidence does not specify exact drug types or durations for injections like cortisone, hyaluronic acid, or PRP, these treatments are sometimes used to reduce swelling and pain. The goal is to make daily activities more comfortable while your ligament recovers. If you have a displaced bone fragment on your X-ray, your surgeon will discuss whether this changes the treatment plan.
Surgery is considered when conservative care does not stop the joint from becoming unstable. If you have a displaced bone fragment, there is a high chance the ligament has become trapped, which usually requires an operation to fix. Your surgeon may offer a repair to restore normal movement or a reconstruction using your own tendon if the ligament is too damaged. These procedures aim to return stability to your thumb so you can play sports and perform daily tasks without pain.
When to see someone
See your GP if you have persistent pain that does not improve with rest. Ask for a specialist review if you feel weakness or instability in your thumb. Seek help if your thumb locks or gives way. Contact your surgeon if symptoms interfere with sleep or work. Sudden worsening of pain also requires attention. Your doctor will use a physical exam and X-rays to check for underlying issues. They may look for a displaced bone fragment, which often means the ligament is trapped and needs surgery. Early assessment helps prevent long-term joint instability.
