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Arthroscopic TFCC Ulnar Bone Tunnel Foveal Repair in Adult Patients

Triangular fibrocartilage complex (TFCC) tears may cause persistent ulnar-sided wrist pain, loss of grip strength, and associated loss of function. Although the majority of TFCC tears can be treated nonoperatively, surgical repair is considered when conservative measures fail. TFCC tears with foveal disruption and instability of the distal radioulnar joint (DRUJ) require direct repair of the TFCC to the ulnar fovea. The traditional method of foveal TFCC repair involves an open surgical approach through the floor of the 5th dorsal compartment. However, this open approach causes disruption of structures such as the dorsal ulnocarpal capsule, the extensor retinaculum, and, potentially, the distal radioulnar ligament (DRUL). This article describes, in detail, the recently developed arthroscopic assisted ulnar foveal bone tunnel repair. This method spares dorsal structures that may be disrupted during an open surgical approach and creates a robust repair of the TFCC deep fibers with restoration of DRUJ stability.


Introduction
A cute or chronic triangular fibrocartilage complex (TFCC) tears may result in persistent ulnar-sided wrist pain, loss of grip strength, and loss of function for patients. Although diagnosis and nonoperative management of TFCC tears are well defined, there remains ongoing discussion about the optimal surgical technique: open vs. arthroscopic.
Surgical management is recommended for acute injuries in high-demand patients, chronic degenerative tears with ulnar impingement, as well as persistent distal radioulnar joint (DRUJ) instability. 1 Although the majority of TFCC tears are treated nonoperatively, one study indicated that over 40% of patients with a TFCC injury may eventually require surgical management. 2 Contraindications to operative intervention include patients who have degenerative changes about the DRUJ or radio-carpal joints, mild symptoms even in the setting of radiographic changes, as well as the lowdemand, medically unfit elderly population. 3 If the patient is ulnar positive (2 mm or greater), then strong consideration should be given to ulnar shortening osteotomy rather than TFCC debridement or repair. These patients are more likely to fail surgical treatment that only addresses the TFCC, and they frequently require subsequent ulnar shortening osteotomy. 1,4 Peripheral TFCC tears without foveal disruption may be treated with the capsular repair technique described by Wysocki et al. 5 However, TFCC tears with foveal disruption and associated DRUJ instability require direct foveal repair. 6,7 Traditionally, foveal TFCC repair

Surgical Technique
Video 1 demonstrates the step-by-step procedures of TFCC ulnar bone tunnel foveal repair. Special instruments used in this procedure are detailed in Table 1.  For foveal repairs, the patient is placed in a supine position with the arm on a hand table , and 10-15 lbs of longitudinal traction is applied with the elbow at 90 . Traction with the wrist in slight flexion allows for ideal visualization and portal placement. Standard diagnostic wrist arthroscopy portals are then placed: 3-4, 6R, and 6U, if necessary. Diagnostic arthroscopy is completed to confirm TFCC injury and identify any other associated wrist ligamentous injuries (lunotriquetral tears, split tears of the ulnolunate, or ulnotriquetral ligaments) that could also require treatment.
The 6R portal allows for instrumentation to debride poor quality tissue about the TFCC and improve visualization. A subcutaneous incision is made along the ulna w2 cm proximal to the joint (Fig 1). A 1.1-mm guidewire (K-wire; Arthrex, Naples, FL) is advanced with approximately 45 of obliquity from the subcutaneous border of the ulna into the wrist joint at the foveal insertion of the TFCC. An intraarticular guide (SLAM Guide; Arthrex) is used to localize the central aspect of the TFCC (Fig 2) to assist with guidewire placement (Fig 3). Once appropriate positioning of the guidewire is confirmed, the guidewire is over drilled with a 3.5-mm cannulated drill (Arthrex) to create the "ulnar bone tunnel" from the subcutaneous border of the ulna to the fovea (Fig 4).
Using the outside-in technique, a fiber stick needle (Micro SutureLasso; Arthrex) loaded with 2-0 nonabsorbable suture (FiberWire; Arthrex) is passed through the ulnar bone tunnel into the volar portion of the triangular fibrocartilage (TFC) (Fig 5). The needle is initially turned clockwise with multiple revolutions, causing the suture to wrap around it. Then, the needle is turned counterclockwise, while  slowly removing it from the joint (Fig 6). This technique allows the suture to stay within the ulnocarpal joint for later retrieval. The arthroscopic probe is used to move the suture dorsally. Subsequently, the fiber stick needle (Micro SutureLasso; Arthrex) is then loaded with nitinol wire (Arthrex) and is placed through the ulnar bone tunnel through the dorsal portion of the TFC (Fig 7). The nitinol wire is then  Application of suture through the triangular fibrocartilage (TFC) using the fiber stick needle. After deploying the loaded 2-0 nonabsorbable suture (FiberWire; Arthrex, Naples FL), the needle (Micro SutureLasso; Arthrex) is initially turned clockwise multiple times as the suture wraps around it. The needle is then turned counterclockwise while slowly removing it from the joint. This technique allows the suture to stay within the ulnocarpal joint for later retrieval. An arthroscopic probe is then used to move the suture dorsally to position it for later retrieval. TFCC, triangular fibrocartilage complex. deployed, and a hemostat is used to bring the suture, in conjunction with the nitinol wire, out of the 6R portal (Fig 8). Once outside of the joint, exterior to the skin, the suture is brought through the nitinol wire. The suture is then brought back into the joint using the nitinol wire, which is still present in the ulnar bone tunnel (Fig 9). This action results in a mattress repair, restoring tension to the TFC.  This suture is then secured to the ulnar shaft with a 2.5-mm knotless suture anchor (PEEK Mini PushLock; Arthrex) through a second drill hole 1 cm proximal to the ulnar bone tunnel (Figs 10, 11, and 12). The TFC may then be probed through the 6R portal to assess for appropriate restoration of tension via the trampoline, hook, and suction tests (Video 1). 6,9,10 Table 2.

Postoperative Rehabilitation
After arthroscopic TFCC foveal repair, patients are initially placed in a sugar tong splint in neutral forearm rotation. At 2 weeks postoperatively, the incisions are examined, and sutures are removed. The patient is transitioned to a removable muenster splint in neutral forearm rotation. At 6 weeks postoperatively, the splint is discontinued. Active/passive wrist motion (flexion and extension) and forearm rotation (supination and pronation) are initiated with skilled occupational therapy. Gradual light strengthening is started at the 10week mark. Return to sport and all other activities are allowed 3 months postoperatively.

Discussion
TFCC tears with foveal disruption can result in persistent ulnar-sided wrist pain with associated loss of grip strength, function, and DRUJ instability. Historically, TFCC tears with foveal disruption have been repaired using open surgical techniques with a surgical   an open approach, protection of the distal radioulnar ligaments, and visualization of other ulnar-sided wrist pathologies, such as tears of the lunotriquetral ligament (LTL), ulnolunate ligament (ULL), and ulnotriquetral ligament (UTL) that may require treatment. One disadvantage of this procedure is the initial learning curve for the surgeon, which may increase operative duration. Advantages and disadvantages of this procedure are presented in Table 3.
In conclusion, arthroscopic ulnar foveal bone tunnel repair is an efficient, minimally invasive surgical technique that produces a robust repair of the TFCC deep  Pearls Use of the 3-4 and 6R portals primarily to allow for adequate working space and visualization of the TFC repair Use of the intraarticular guide to precisely identify the TFC foveal insertion Ensuring that the drill is centered on the subcutaneous border of the ulna Twirling the fiber stick needle clockwise, and subsequently, counterclockwise, allowing for the suture to stay within the joint

Pitfalls
Inadequate traction resulting in poor visualization of the ulnocarpal joint Inadequate spread between the passage of the suture in the volar direction through the TFC and the nitinol wire dorsally through the TFC, which could result in suture cutout Failure to exteriorize the nitinol wire and suture in a single pass through the 6R portal, which could result in a tissue bridge that interferes with repair completion Adequate distance (1 cm) between the ulnar bone tunnel and the drill hole for the knotless anchor, mitigating the risk of fracture TFC, triangular fibrocartilage; TFCC, triangular fibrocartilage complex. e1760 fibers and results in improved grip strength, patient outcome scores, and DRUJ stability.