Atraumatic Bucket Handle Abnormality of the Triangular Fibrocartilage Complex in an Adolescent

Abstract

Background  Congenital abnormalities of the triangular fibrocartilage complex (TFCC) are rare and could be mistaken for a traumatic lesion. It is important to recognize these anatomical variations and to realize they do not always require treatment.

Case Description  An incidental finding of an atraumatic bucket handle abnormality of the TFCC in a 15-year-old male, who was treated arthroscopically for dorsal wrist pain. This structure was resected, thus obtaining a normal looking peripheral TFCC.

Literature Review  Literature regarding congenital abnormalities of the TFCC is limited to a meniscoid articular disc or a congenital perforation. To our knowledge, an atraumatic bucket handle abnormality has not been described yet.

Clinical Relevance  This congenital abnormality of the TFCC could be mistaken for a traumatic lesion on MRI, or during wrist arthroscopy; therefore, it is important to realize that this entity may occur and does not require treatment.

Anatomical variants of the triangular fibrocartilage complex (TFCC) described in the literature are limited to a meniscoid articular disc or a congenital perforation. ^{1 2 3} We encountered a different kind of anomaly of the TFCC during wrist arthroscopy.

In this study, we report on a case regarding the incidental finding of an atraumatic bucket handle abnormality of the TFCC, during arthroscopy in a 15-year-old adolescent, who has had persistent left-sided dorsal wrist pain in the past 5 years. He had no history of trauma. Given the age, absence of trauma, and the smooth borders of the bucket handle, we believe this to be an anatomical abnormality, rather than a traumatic or degenerative tear.

This bucket handle could be mistaken for a traumatic lesion. However, it is important to realize that this entity may occur and does not always require treatment.

Case Report

A 15-year-old adolescent presented with left-sided, atraumatic dorsal wrist pain with intermittent swelling in the past 5 years. The pain aggravated during physical activities and writing, causing him to cease most of his recreational activities. Clinical examination showed a normal range of motion and a discrete but tender swelling over the scapholunate interval. There were no signs of ligamentous instability. There was some tenderness over the ulnar snuff box but forced pronation and supination or rotation-compression tests were painless. An MRI scan showed a dorsal multilocular cyst, arising from the scapholunate ligament and intercarpal joints, and a discrete tear in the radial insertion of the TFCC.

Given the severe impact on daily activities, despite bracing and physiotherapy, arthroscopic resection of the ganglion cyst with synovectomy was performed. The scapholunate ligament showed Geissler grade II laxity with mucoid degeneration and severe synovitis in the radiocarpal and midcarpal joint. The tear in the radial insertion of the TFCC was debrided. Peripherally, a bucket handle-like structure with smooth edges was seen, with an intact TFCC underneath. The cartilage on the lunate and triquetrum appeared normal and there was no synovitis in this part of the wrist. The structure did not have any connections to ligaments or the joint capsule ( Fig. 1 ). The smooth edges without fraying, along with the young age of the patient and absence of trauma, raised the suspicion of an anatomic anomaly, rather than a traumatic or degenerative tear. Since it did not seem to have any structural function, but could cause mechanical problems, we resected it, thus, obtaining a normal looking peripheral TFCC ( Fig. 2 ).

Fig. 1.

Arthroscopic views from 3–4 portal, hook through 6R portal. ( A ) The structure mimics a tear, ( B ) but an intact peripheral TFCC can be seen underneath.

Fig. 2.

( A ) Arthroscopic views from 3–4 portal, resection of the structure with a grasper; ( B ) TFCC after resection of the abnormal structure.

In retrospect, this structure could be suspected on the MRI images, as an added structure on the ulnar half of the TFCC ( Fig. 3A and B ).

Fig. 3.

Preoperative T2 weighted ( A ) coronal and ( B ) sagittal MRIs of the wrist. White arrows indicate the additional structure. ( C ) and ( D ) Postoperative images show the changed aspect.

The patient recovered well and was pain free 1-month postoperatively, with only some residual stiffness. The ulnar side of the wrist was not painful on palpation. Seven months after the operation, a new MRI was performed for recurrence of dorsal pain, while the ulnar side remained pain free. This only showed some dorsal synovitis, the structure on the TFCC was no longer visible ( Fig. 3C and D ). The synovitis was treated conservatively with physiotherapy and a corticosteroid injection.

Discussion

Anatomic variability of the ulnar ligamentous complex has been established in embryological research by Hogikyan et al, but the literature regarding anatomical variants in the TFCC is rather limited. ⁴ Three articles reported on congenital atraumatic abnormalities of the TFCC, two of them involved a case report on a meniscoid articular disc, and the third reported on a congenital perforation. ^{1 2 5}

A cadaveric study reported on an incidence of congenital TFCC perforations of 18.8% in infants and 25% in foetuses. ³ We were unable to find any description of an anatomical variation of the TFCC other than a perforation. Bucket handle tears have also been previously described by Theumann and Jose; however, a history of prior trauma is present in these articles. ^{6 7}

We suspect our finding to be a previously undescribed anatomic variation of the TFCC. A traumatic or degenerative TFCC lesion is unlikely in this patient given his age, the absence of trauma and the aspect of the structure on arthroscopy. We encountered it as an incidental finding, during wrist arthroscopy for an occult dorsal ganglion cyst. Since this could be mistaken for a traumatic lesion on MRI, or during wrist arthroscopy, it is important to realize that this entity may occur and does not require treatment.