A hyperextension injury of thumb can result in an ulnar collateral ligament (UCL) injury. The UCL is a stout, thick and strong ligament on the inside of the thumb at the level of the metacarpophalangeal joint. It is essential for the stability and patients who have completely ruptured this will notice instability on key grip pinch. It can be quite debilitating and depending on the degree of rupture surgery may be advised.
If the UCL is partially sprained or damaged, it may be successfully treated with splint immobilisation. However a completely ruptured UCL may well required surgical repair. The anatomy is such that is possible for the ligament to rupture and each end of the ligament end up on either side of a covering fascial structure known as the adductor aponeurosis resulting in what is called a Stena lesion – in this situation , the UCL will never heal well and surgery is usually recommended.
Sometimes the UCL is avulsed taking a bony fragment with it. If the bony fragment is displaced away form it’s origin then the bony fragment is fixed back onto it’ s origin.
After surgical repair, splintage and hand therapy is often required
UCL Reconstruction using Free Tendon graft
In the unusual situation of a delay in treatment for an ulnar collateral ligament rupture (beyond weeks/months), direct repair may not be possible and sometimes a reconstruction of the ligament using a tendon free graft is performed.