The patient’s wrist is positioned, traction applied, and arthroscopic access established as described in Chap. 1. Initial evaluation is typically performed with the arthroscope placed in the 3,4 portal and instrumentation in the 6-R portal. Inflow pressure should be minimized in order to allow the TFCC to assume a more normal position within the ulnocarpal joint and minimize blanching, which allows for easier identification of inflamed soft tissue. Visual examination for obvious signs of injury or tears is performed, and associated synovitis or chondromalacia is also noted (Fig. 5.2a). Pronation and supination may aid in visualization of the entire TFCC, and stability of the DRUJ can be assessed with manual stress testing. If necessary, the arthroscope may also be moved to the 6-R portal to better view the radial and ulnar attachments of the disc. A probe is used to assess the integrity of the fibrocartilage by palpating the disc for intrasubstance tears, and when depressed it should readily spring back into its normal position (Fig. 5.2b). Loss of this so-called trampoline effect can indicate either peripheral or foveal detachment [41]. The hook and drag tests use the probe to apply traction along the periphery of the TFCC, and displacement vertically or in the direction of traction similarly indicates either a peripheral tear or foveal injury [6]. If a reparable tear is identified, its full extension must be explored in order to determine whether the repair should be to the subsheath only or, in the case of deep fiber involvement, directly to the ulna [15].

Once the diagnosis of a Type 1A tear is made, arthroscopic debridement is the treatment of choice given the central disc’s poor vascularity and inability to heal. Detailed management of tears amenable to repair will be covered in subsequent chapters. The goal of the procedure is to debride unstable flaps of the central fibrocartilage that are likely to catch on surrounding tissue back to a stable rim. Biomechanical studies demonstrate that up to 2/3 of the central region can safely be resected without destabilizing the DRUJ; more important is to avoid damage to the peripheral 2 mm of the TFCC as this tissue contains the dorsal and volar radioulnar ligaments [14, 42] (Video 5.1). Debridement techniques have been described with multiple instruments including scalpels, banana blades, shavers, radiofrequency probes, and lasers [43–45]. Each has its own advantages and disadvantages, and the ideal instrument is ultimately the surgeon’s preference. Ours is to use a banana blade or arthroscopic shaver to perform the bulk of resection followed by radiofrequency ablation, if necessary, to stabilize the borders of the resection (Fig. 5.2c, d). As with arthroscopic evaluation, debridement is started with the arthroscope in the 3,4 portal and instrumentation is introduced via the 6-R portal. The radial side of the torn fibrocartilaginous disc is outlined and resected with the blade, then removed with an arthroscopic grasper. The arthroscope is then moved to the 6-R portal, and with instrumentation through the 3,4 portal the same procedure is performed on the ulnar side of the tear. The TFCC is then reexamined to ensure the absence of any further unstable tissue and the integrity of the peripheral ligaments (Fig. 5.2e). The LT ligament and articular surfaces should also be examined and repair or debridement performed as indicated. In most cases, acute IA tears should not have significant carpal chondromalacia or LT ligament insufficiency as these are more often seen with chronic Type II patterns.

In the case of a patient with a Type 1A tear and concomitant positive ulnar variance, most authors argue for the addition of a primary ulnocarpal decompression along with TFCC debridement [8, 22, 28, 29, 46, 47]. The ulnar-shortening osteotomy [46] and ulnar wafer procedure [47] have both been proposed as treatment options that can be combined with arthroscopic debridement. In an early report of arthroscopic TFCC debridement Osterman noted some patients with positive ulnar variance to have degenerative chondromalacia of the ulnar head despite traumatic mechanisms, suggesting some tears may be acute-on-chronic injuries [48]. Minami subsequently reported that patients with positive ulnar variance have inferior outcomes compared to those with neutral or negative variance after debridement alone, and argued for primary ulnar-shortening osteotomy for these patients [46, 49]. Ulnar-shortening osteotomy is also a successful secondary procedure for persistent pain after primary debridement regardless of preoperative ulnar variance [50], suggesting dynamic positive ulnar variance may contribute to failure even if routine X-rays are normal [51]. In comparing primary ulnar wafer resection to ulnar-shortening osteotomy, when combined with debridement both show equivalent postoperative pain relief and function. Higher rates of tendinitis and reoperation (for hardware removal) have been reported with ulnar-shortening osteotomy, however [28, 52].

As previously discussed, if only the central region of the TFCC is debrided and the periphery remains intact, the biomechanics and stability of the wrist will not be affected. Further, as there is no repair to protect, postoperative immobilization is unnecessary and patients are able to begin rehabilitation immediately, including unrestricted active and passive motion and light progressive strengthening once pain is diminished [42]. If an ulnar-shortening osteotomy or ulnar wafer resection is performed a splint is used for 6 weeks to protect the osteotomy or allow a clot (and subsequently fibrocartilage) to form over the distal ulna, respectively. Strengthening exercises are delayed until the osteotomy is healed radiographically in the setting of an ulnar shortening (typically 6–8 weeks)

Arthroscopic debridement has become the treatment of choice and standard of care for Type 1A TFCC tears, offering superior visualization of the TFCC with a less invasive approach and superior outcomes when compared to open procedures. In separate studies, Osterman and Roth both described the initial technique of arthroscopic TFCC debridement [48, 53]. Osterman also reported on 52 patients prospectively followed after arthroscopic debridement with either a motorized shaver or pituitary rongeur for traumatic or degenerative TFCC tears. At an average follow-up of 23 months, 73 % were pain-free and 12 % further were improved; amongst the five patients who failed treatment no relationship to ulnar variance was identified [48]. Subsequent studies have found similar results. Comparing arthroscopic debridement in 11 posttraumatic vs. 5 degenerative cases, Minami found a posttraumatic etiology to be associated in all cases with an excellent recovery based on superior patient satisfaction, pain relief, and function [49]. Using Minami’s criteria, Miwa also found good or excellent results in 9/10 patients undergoing debridement for Type 1A tears [54]. Using the modified Mayo Wrist Score, Husby and Haugstvedt reviewed 32 patients at a median of 39 months after arthroscopic debridement and found 27 good or excellent results vs. 4 fair and 1 poor result; all but 2 patients in their study would have had surgery performed again [55].

Amongst patients failing debridement alone, Hulsizer found a subsequent ulnar shortening osteotomy resulted in complete relief of pain for 12/13 patients regardless of preoperative ulnar variance [50]. In cases of positive ulnar variance, failure rates of up to 25 % have been described for debridement alone [49], and primary procedures to decompress the ulnocarpal joint should be considered in addition. Outcomes after debridement with ulnar-shortening osteotomy or an ulnar wafer procedure are equal or superior to those published for debridement alone. However, rates of reoperation, most commonly removal of osteotomy hardware, as well as ulnar-sided tendinitis are higher with ulnar-shortening osteotomy, leading some authors to favor the wafer procedure [28, 52]. Animal models also suggest that the clot formed by bleeding from the distal ulna may allow for fibrous reconstitution of the debrided central TFCC, but this has yet to be shown in humans [56].