Our study showed that incorporating augmented DCI in TFCC repair for patients with an intraoperative positive intraoperative ballottement led to satisfactory postoperative clinical and functional results and could be considered as an indication for DCI augmentation. Such an augmentation led to significantly lower reoperation rates with patients having significantly higher grip strength. However, patients undergoing DCI might experience a brief period of decreased wrist ROM. According to the Atzei classification, TFCC fovea tear (class II, III) required foveal TFCC repair [4, 32]. The neglected TFCC fovea tear might contribute to chronic DRUJ instability [5] resulting in decreased grip strength or limited wrist ROM [33]. Despite the favorable outcomes reported for “transosseous repair [6–8]” “fovea repair with suture anchors [4, 9, 10]”, re-operation rates have been documented in the range of 6.7–30% [8, 34–37]. Discrepancies in clinical results and reduced efficacy of fovea repair may be attributed to (1) the poor quality or irreparable remnants of TFCC fovea tears that cannot stabilize DRUJ, (2) insufficient coverage area for sutures or knots, increasing the risk of TFCC cut-through during knot tying, and (3) inadequate foveal debridement or improper positioning of bony tunnels, leading to limited bone-to-ligament regeneration capacity.
Recent studies comparing DRUJ stability after capsular repair and transosseous repair have produced varying results: Ruch et al. [38] demonstrated no significant difference, while Johnson et al.[39] indicated greater stability with transosseous repair. However, the critical factor for successful TFCC repair lies in the healing potential of the contact surface, which is notably poor in ligament-to-bone repair (fovea repair): 1. Ulna fovea has a “band shaped”-like footprint [40], whereas “suture anchor repair” and “transosseous tunnel repair” only provide a point contact area between the TFCC remnant and the ulna fovea; 2. “ Enthesis” refers to the insertion site of a tendon, ligament or joint capsule into bone [41]. Fovea repair, “transooseous repair” or “suture anchor repair,” requires the reattachment of TFCC remnant parts into the ulna fovea. Few vessels penetrate the enthesis due to a calcified barrier [42]. In contrast, capsular repair may be more effective in enhancing the healing potential of the TFCC through ligament-to-capsule repair compared to [43] ligament-to-bone repair. However, a comprehensive review involving 825 cases across 30 studies revealed post-operative distal radioulnar joint (DRUJ) instability rates of 12.1% for capsular repair and 10.1% for fovea transosseous repair. Regarding re-operation rates, they were 7.9% for capsular repair and 5.5% for fovea transosseous repair [16]. These results indicate that intraoperative instability of the DRUJ can be a concern in both primary methods of TFCC repair. Therefore, employing an intraoperative DRUJ stability test could be essential for identifying potential postoperative instability and the failure of TFCC repair. Augmentation with DCI can help prevent postoperative DRUJ instability and the need for subsequent reoperation.
The intra-operative ballottement test is a simple method for evaluating DRUJ stability after arthroscopic TFCC repair. A positive result suggests that the strength of the repaired TFCC alone may be insufficient to maintain DRUJ stability. DCI can be employed as a supplementary method to enhance DRUJ stability. Using DCI as a sole treatment for patients with DRUJ instability has been successful in restoring DRUJ stability in 97.8% of cases, with 93.6% of patients experiencing pain relief through this approach [17–25]. In a long-term study spanning 10 years, it was observed that DCI effectively restored wrist function to levels comparable to the contralateral hand. DCI can also function as a secondary stabilizer, following a similar bridging concept to that of the internal brace used in anterior talofibular ligament [44] or knee medial collateral ligament repair [45]. When combined with the suture tap and bone anchors, it can reinforce ligament strength and prevent injury recurrence during the rehabilitation process [44]. Similarly, DCI can restore intact DRUJ kinematics and radioulnar ligament reconstructions in chronic DRUJ instability [46]. In the present study, recurrent DRUJ instability was found to be significantly lower in patients with the augmentation of DCI, compared to 3.7% and 1.1% in CR group 1 and “DCI group 2, with a significant difference. Thus, we believe that DCI could be an effective method for addressing intraoperative DRUJ instability following TFCC capsular repair.
In this treatment protocol, we aim to outline the procedures necessary to restore the integrity of TFCC and DRUJ capsules: (1) “TFCC capsular repair” combines the benefits of the inside-out and outside-in techniques, reducing the cut-through rate, purchasing the wide contact area between the ulna fovea and adhering TFCC remnant part with the surrounding tissue to reinforce the DRUJ stability. The crux of transcapsular repair is the ligament-to-soft tissue healing process. Therefore, non-absorbable suture 2 − 0 ethibond was selected to provide reliable tension support. (2) Intraoperative ballottement test could be used to check for integrity of the DRUJ stability, grade 0 indicates that “TFCC transcapsular repair” was sufficient to maintain DRUJ stability, while grade I, II or III suggests that DRUJ laxity or subluxation existed after transcapsular repair, and the subsequent augmentation for DRUJ stability was needed. (3) Dorsal DRUJ capsular imbrication worked by tightening the redundant laxity of dorsal DRUJ capsule, thereby reducing the subluxation of ulna head and reattaching the DRUL to the tightened DRUJ capsule under wrist full-pronation position. Tension of the imbricated capsule can be optimized to stabilize DRUJ with the utilization of two suture anchors over the dorsal cortex of the radius sigmoid notch. Our results indicated a slightly higher rate of postoperative distal radioulnar joint (DRUJ) instability in Group 1, which underwent only TFCC capsular repair, compared to Group 2, which received both TFCC capsular repair and dorsal DRUJ capsular imbrication. This implies that late DRUJ instability may manifest in patients who initially tested negative in the intraoperative ballottement test but only underwent TFCC repair. It also implies that DCI is a reliable procedure to build up the DRUJ stability.
A major concern about our methods was that wrist stiffness was found approximately postoperative 6 months in the DCI group. However, wrist ROM were comparable to the CR group after midterm follow-ups. Furthermore, grip strength of DCI was not affected even with decreased wrist ROM. Another issue to consider was that tying knots during the transcapsular repair may lead to transient dorsal ulnar sensory nerve irritation due to intra-operative retraction; however, symptoms were noted to subside within 2 weeks postoperatively. This study has its own limitations. Firstly, it focused solely on surgical outcomes and functional measures, lacking postoperative axial MRI to verify the repositioned DRUJ. Secondly, being a retrospective comparative study with midterm follow-up, a longer-term investigation is needed to validate the observed clinical outcomes. Third, the intraoperative ballottement test employed in this study remains subjective. Future studies should consider standardizing pull strength and translation distance measurements to enhance the accuracy of identifying subtle cases of DRUJ instability following TFCC repair. Finally, we did not include a control group comprising patients with persistent instability after TFCC repair who did not receive additional augmentation treatment to enhance DRUJ stability. However, establishing such a control group presented ethical and clinical challenges, as leaving untreated cases of persistent DRUJ instability were not considered feasible.