How does a person decide when you need surgery? I have a torn ligament in my wrist (the one between the scaphoid bone and lunate bone — I’m learning a lot about anatomy). Can’t get a straight answer out of my doc. Says I can try going with a splint and give it time but surgery is always an option. What would you recommend?

To help answer your question, we turned to an extensive review of treatment for scapholunate injuries recently published by the Department of Hand and Upper Extremity Surgery at the Hospital for Special Surgery in New York City. In this article, orthopedic (hand) surgeons provide an extensive, detailed, and very thorough review of scapholunate instability. They discuss what happens and how to treat this problem.

A little bit of anatomy goes a long way in understanding the complexities of this injury and why treatment isn’t always a cut-and-dried decision. The scapholunate joint describes a place in the first row of carpal (wrist) bones where the scaphoid bone and the lunate bones meet and greet, so-to-speak. The scaphoid is a small bone on the thumb side of the wrist next to the radius bone of the forearm. The lunate is in the middle of the row of carpal bones sandwiched between the scaphoid and the triquetrum on the little finger side of the wrist.

These three bones move together as part of wrist motion. The scaphoid and lunate are held together by the scapholunate interosseous ligament (SLIL). Perhaps this is the area of your injury. This ligament is a tough, C-shaped piece of connective tissue.

When the SLIL is intact, the scaphoid and the lunate move as one unit. Damage or injury to the SLIL can result in these two bones moving separately and independently of each other — a situation referred to as scapholunate instability. Extra, unintended shifting and motion of these bones can cause excruciating wrist pain, weakness, and loss of function. Just lifting a cup of coffee or brushing the teeth can be an agony.

Treatment is important to reduce pain, restore normal wrist and hand motion, and prevent joint loading and degenerative changes that could lead to further disability from arthritis. Treatment ranges from conservative (nonoperative) care to surgery. The decision about what to do and when to do it depends on five key factors.

These factors include 1) condition of the scapholunate interosseous ligament, 2) amount of tissue left for a repair, 3) position and angle of the scaphoid bone, 4) possibility of realigning the carpal bones, and 5) condition of the cartilage lining the involved wrist joints.

It is generally agreed that nonoperative treatment is an acceptable choice for those patients who 1) don’t want surgery, 2) still have good grip strength, 3) activity level of the patient, and 4) level of pain. There’s no doubt that instability at the scapholunate joint will eventually result in degenerative arthritis. But the progression to this stage is unpredictable and could be years for some patients.

That’s why conservative care is offered to patients who could get by with a splint and activity modification. It’s entirely possible to choose nonoperative care for years — even decades and manage just fine. Starting with nonoperative care makes sense because delaying surgery doesn’t necessarily set you back and then surgery is always a next-step alternative.