Combined Palmer Type 1A and 1B Traumatic Lesions of the Triangular Fibrocartilage Complex A New Category.

We present a series of eight patients who underwent wrist arthroscopy for presumed solitary tears of the triangular fibrocartilage (TFC) and were, instead, found to have combined 1A (central tear) and 1B (ulnar avulsion) tears. The Palmer Classification does not currently categorize this combined pattern. All but one patient had a traumatic injury. Each subject had preoperative radiographs and MRI scans. TFC tears were evident on all MRI scans, though only one was suggestive of a combined tear pat - tern. Surgical management included arthroscopic central tear debridement and ulnar peripheral repair. Average follow-up was 22 months. Grip strength in the affected hand improved from 16% deficit as compared to the unaffected side, to 3.5% deficit postoperatively (p = 0.003), and visual analog scores (VAS) decreased from an average of 7.1/10 preoperatively to 2.3/10 postoperatively (p < 0.001). There was no statistically significant change in wrist range of motion (ROM), however. Arthroscopic debridement of the central perforation (1A lesion) with concomitant repair of the ulnar detachment (1B lesion) resulted in functional and symptomatic improvement. This combined 1A/1B TFC injury is not reliably diagnosed preoperatively and should be considered a new subset in the Palmer classification, as this will raise awareness of its presence and assist in preoperative planning of such lesions.