Slideshow
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Figure 1. Anteroposterior radiograph of thumb without signs of arthritic changes. Credit: Dagan Cloutier, MPAS, PA-C
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Figure 2. Lateral view of the thumb. Dagan Cloutier, MPAS, PA-C
A 34-year-old woman presents with left thumb pain and instability that has been present for over 4 years. The patient notes that she fell 4 years ago and landed on the thumb, which then became painful. She has ignored the injury and has never sought treatment. The initial pain improved after 4 weeks but the thumb has never really felt stable since (Figures 1 and 2). She reports increased pain with grasping objects such as turning a doorknob and picking up her young child, which may indicate ulnar collateral ligament (UCL) instability. On physical examination, she has significant laxity to the UCL of the thumb (>30-degree difference with valgus stress compared with the right thumb).
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The ulnar collateral ligament (UCL) provides stability at the metacarpophalangeal (MCP) joint during tasks like grasping or pinching objects with the thumb. This patient presents with chronic UCL instability with no evidence of arthritic changes on radiographs. The original injury should have been treated with a thumb spica cast for 6 weeks to allow for UCL healing. Ligament tears are generally considered chronic if they present more than 6 weeks out from injury.1,2
In the case of a chronic UCL tear, direct repair is not a viable treatment choice as the quality of the torn UCL tissue deteriorates over time. Ligament reconstruction with a tendon graft is the most common procedure to restore MCP joint stability for chronic UCL tears. Patients typically return to normal activities 3 months postoperatively from ligament reconstruction with an equal grip strength expected. Arthritis in the MCP joint is a contraindication for a ligament reconstruction procedure. Joint fusion is a last resort option for patients who have developed arthritis in the joint and continue to have pain and instability.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopedics for Physician Assistants.
References
1. Pulos N, Shin AY. Treatment of ulnar collateral ligament injuries of the thumb: a critical analysis review. JBJS Rev. 2017;5(2):e3. doi:10.2106/JBJS.RVW.16.00051
2. Poggi DS, Massarella M, Piccirilli E. The treatment of chronic ulnar collateral ligament of the thumb injury using extensor pollicis brevis: surgical technique. J Hand Surg Glob Online. 2020;3(1):56-60. doi:10.1016/j.jhsg.2020.10.002
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