Acute traumatic avulsion or rupture of the ulnar collateral ligament (UCL) of the thumb metacarpophalangeal (TMP) joint is a frequent sports-related injury. If not diagnosed and treated early, it may lead to chronic instability, pain, and loss of pinch and grip strength and possibly osteoarthritis. UCL insufficiency may be treated by various techniques, such as bone anchors, transosseous sutures with or without a pull-out button, tendon grafts, or with TMP joint fusion in neglected cases with arthrosis. A simple technique of internal fixation of an avulsion fracture of the distal attachment of the UCL on the proximal phalanx of the thumb using transosseous sutures is described.
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Described as early as 1939, acute ulnar collateral ligament (UCL) insufficiency was originally considered a wintersports-related injury of the thumb metacarpophalangeal joint (TMP), and hence the synonym “skier’s thumb” [
The incidence of UCL insufficiency in the USA is estimated at 200,000 patients per year. It is the most frequent injury of the base of the thumb (86%) [
Surgical treatment within four weeks after injury is recommended in dislocated or unstable injuries [
The aim of this report is to describe an easily applied, low-cost surgical technique for the anatomic fixation of the distally avulsed bony attachment of UCL, using transosseous sutures.
A 15-year-old boy presented at the emergency department with a painful, swollen hand after a fall from his bicycle. On x-rays, a displaced avulsion fracture at the distal attachment of the UCL was diagnosed. The fracture was displaced more than 1 mm and malrotated. The size of the avulsed fracture was more than one-third of the joint surface (Figure
The yellow arrow indicates the avulsion fracture of the attachment of the ulnar collateral ligament of the thumb metacarpophalangeal joint.
Surgical treatment was decided. Instability was confirmed under general anesthesia. The TMP joint angulated 34 degrees when a valgus stress was applied. Further displacement of the fracture was evident with valgus stress (Figure
Valgus laxity of 34 degrees at the TMP joint and further displacement of the avulsed fracture fragment are evident (yellow arrow).
TMP: thumb metacarpophalangeal joint.
A curved dorsomedial skin incision over the TMP joint was performed. The dorsal cutaneous branch of the radial nerve was identified and protected. The aponeurosis of the adductor pollicis muscle was cut transversely, and the UCL was inspected. The fracture gap at the base of the proximal phalanx of the thumb was cleared of debris and clots. The avulsed bony attachment of the UCL was reduced. Under image intensification and gentle oscillating movements (free-hand), two 16-gauge needles were inserted through this fragment. The needles were further advanced into the proximal phalanx of the thumb. They converged and penetrated the radial cortex of the proximal phalanx and the skin. A very small (1-2 mm) incision was made to connect the exit points of the two needles (Figure
(A) Image intensification. (B) Intraoperative view.
UCL: ulnar collateral ligament
One non-absorbable, size 1, nylon suture was passed from proximal to distal through the one needle and returned through the other. The needles were removed. Blunt dissection with a small mosquito clamp from the radial skin incision to the radial cortex of the proximal phalanx was carried out, in order to allow direct contact of the suture loop with the radial cortex. The free ends of the suture were pulled and tied. Internal fixation of the bony avulsion of the UCL with the base of the proximal phalanx of the thumb by means of transosseous sutures was completed (Figures
The yellow arrow indicates the loop of the suture, which will be in contact with the lateral cortex. The blue arrow indicates the free ends of the transosseous suture after removing the transosseous needles.
Anatomic reduction of the avulsed attachment of the UCL is seen on the anteroposterior (A) and lateral (B) x-ray views of the operated thumb. The arrows indicate the location of the fracture.
UCL: ulnar collateral ligament
The TMP joint was stable on valgus in extension and in 30 degrees of flexion. The wound was closed with 3.0 nylon mattress sutures. A short-arm splint with a thumb spica was placed, protecting the thumb from abduction and valgus. Stitches were removed after two weeks. The splint was removed after one month. A removable splint with a thumb spica was placed, and the patient started physical therapy. Rehabilitation was uneventful. Unrestricted return to previous activities was accomplished at three months postoperatively.
The aim of any surgical treatment of unstable complete ruptures of the UCL is to restore stability of the TMP joint, and hence to restore pinch strength, grip strength, and hand function [
Various surgical techniques are available, such as direct primary repair, suture anchors, interference screws, transosseous sutures with or without a pull-out technique, arthroscopic-assisted reduction of the avulsed fragment, and reconstruction using autografts or allografts. In case of chronic degenerative arthritis, fusion of the TMP joint is the only option to deal with chronic pain and hand malfunction [
A pull-out technique using a button in direct contact with the skin on the radial side of the thumb was widely used in the past for the treatment of acute injuries of UCL [
In the presented case, the avulsed bony fragment comprised almost one-third of the joint surface. Thus, anatomic reduction and stable internal fixation was decided. Rein et al. described a similar technique, but the suture was passed only through the proximal phalanx of the thumb. In fact, it was used like a suture of a bony anchor to fix the avulsed stump of UCL to its anatomic attachment. Small size avulsion fractures were treated as non-osseous avulsions. For large bony avulsions, Rein et al. recommended additional fixation either with K-wires or with a small 1.1-1.3 mm screw, but such cases were not presented in their study [
In case of a large bony avulsion of the UCL, anatomic fixation of the fracture will automatically restore TMP joint stability. The presented surgical technique is an internal fixation technique of the bony avulsion of UCL using transosseous sutures.
A simple surgical technique for the internal fixation of a bony avulsion of the distal attachment of the UCL of the TMP joint using transosseous sutures is presented. Early anatomic restoration of the bony avulsion leads to rapid healing of UCL, and hence to early restoration of normal function. Furthermore, the presented surgical technique avoids the complications of a pull-out button technique and the high cost of suture anchors.
The authors have declared that no competing interests exist.
Consent was obtained by all participants in this study