Atzei class 1
- isolated peripheral TFCC tear of the distal (styloid) attachment
Atzei class 2
- peripheral TFCC tear of both attachments the styloid and foveal insertion
Atzei class 3
- isolated peripheral TFCC tear of the proximal (foveal) attachment
- avulsion fracture of the TFCC insertion
Atzei class 4
- extensive TFCC tear, which can not be repaired by common capsular repair or foveal fixation
- degenerative or frayed tear edges which do not hold sutures and show poor healing properties
Atzei class 5
- peripheral tear and associated distal radioulnar joint (DRUJ) arthritis or osteochondral injury
Case Discussion
This is an illustration of the Atzei classification for peripheral triangular fibrocartilage complex (TFCC) tears 1-3, which are classically summarized as Palmer 1b lesions.
Due to better vascularization of the peripheral zone of the triangular fibrocartilage complex, peripheral lesions are more amenable to surgical repair than the central mostly avascular zone 4. Different surgical treatment strategies are depending on the exact location and extent of the lesion, which is covered in this classification.
A strength of this classification is that it offers clear therapeutic recommendations for each category:
An Atzei class 1 lesion requires capsular suture class 2 and class 3 tears foveal attachment, class 4 and class 5 lesions require more extensive and sophisticated repair as e.g. tendon graft in case of a class 4 lesion or arthroplasty in case of a class 5 lesion 1-3.
Remarks:
On imaging, it is particularly important to point out isolated lesions of the foveal attachment thus Atzei class 3 lesions, since they also have a normal appearance on arthroscopic inspection. If the hook test is not performed during arthroscopy, they can be missed.