The important finding of this study is that the arthro-Broström procedure combined with endoscopic retinaculum augmentation using all-inside lasso-loop techniques is reliable and safe. The goal of the ligament reattachment should be focused on the durable biomechanical stability and improving ligament-bone interfaced healing. Even though the modified Broström-Gould repair technique was considered the gold standard, there is still controversy on the augmentation of the inferior extensor retinaculum (IER) [5, 6, 20, 21]. Behrens reported that there is no significant biomechanical difference between traditional Broström repair and the modified Broström-Gould repair; reinforcement of the IER may be a marginal procedure at the time of surgery . However, according to another classic biomechanics research, the augmentation of the IER provided protection to the primary ATFL repair within ankle inversion conditions . Moreover, elongation of the repaired ATFL was significantly higher with unprotected motion of the ankle . In a long-term clinical study of arthroscopic-assisted Broström-Gould repair, arthroscopic ATFL repair with IER augmentation can provide similar results as the gold standard ATFL and CFL repair. At the last appointments, 86.7% of active patients practiced normal sports activities at the same preoperative level without major complications . Cordier et al. described the all-arthroscopic Broström-Gould technique using an automatic suture passer, excellent clinical results were observed with a median follow-up time of 28 months while only one case required a revision surgery . According to previous studies, type-1 and most type-2 ATFL lesions only reattachment surgery was required without IER augmentation [9, 25, 26]. Actually, for type-3 ATFL lesions and some high-level athletes with type-2 ATFL lesions could be reinforced with IER. For those type-4 ATFL lesions, the ligament reconstruction, in my opinion, is the good choice.
In most series with percutaneous or arthroscopic Broström-Gould techniques, once passed through the IER, the sutures are then tied in a horizontal mattress configuration [1, 13–15]. These procedures are most vulnerable, depending on the location and quality of the IER . Actually, the stitch method may have influenced the durability of the repaired ligament. According to Takao et al’s recent study, weight bearing was safe, after day one, using the modified lasso-loop technique for arthroscopic ATFL repair . In our series, all-inside lasso-loop stitch techniques were used to improve tissue reattachment of the ATFL remnant and the IER. At the final follow-up, the mean Cumberland Ankle Instability Tool (CAIT) scores, The Karlsson-Peterson scores were 86.63 ± 6.69 and 90.17 ± 4.64, respectively. Moreover, the results of stress fluoroscopic tests were improved significantly after surgery. According to the patients’ survey, all patients returned to their previous level of sport activities. Fortunately, no recurrent ankle instability was encountered at the final follow-up.
Furthermore, the stem of the IER could be accurately identified and separated under endoscopic visualization in the present study. According to Jeong’s previous report, the IER reinforcement wasn’t feasible in some cases (n = 10, 24.4%) due to the distance being too far between the tip of the fibular and the IER, moreover, the IER wasn’t found in 6 cases. In his study, the average distance between the IER and the tip of the fibular was 9.8 mm (range, 5–22 mm); when this distance was longer than 18 mm, reinforcement of the IER was not possible . Actually, the structure used to reinforce the ATFL repair in most cases is the sural fascia, not the stem of the IER. The sural fascia is probably easy to tear during early rehabilitation. Dalmau-Pastor et al. reported that the stem of the IER, the only part that could be used in the augmentation of an ATFL repair, is often difficult to identify and reattach through a limited small incision or percutaneous procedure . In our cases, the average distance between the proximal margin of the IER and anterior margin of the lateral malleolus is 8.8 ± 2.58 mm (range, 5–15 mm). This distance was longer than 10 mm only in 6 cases. Performing the sufficient augmentation of the IER was obtained due to accurate separation of the IER under endoscopic visualization, even though two cases with a thin stem of the IER were observed during surgery. In addition, the released IER was attached to the anterior margin of the lateral malleolus (the footprint of the ATFL) not the tip of the fibular. Appropriate tension of the augmentation, not only protects the repaired ATFL remnant, but also avoids the avulsion of the reinforced IER during postoperative rehabilitation (Fig. 6C).
When arthroscopic assisted repaired techniques were applied, the entrapment of the superficial peroneal nerve or sural nerve is another important issue. The concept of a “safe zone” includes the distal fibula, the superior margin of the peroneal tendons and the intermediate branch of the superficial peroneal nerve was recommended to prevent this problem . In a recent study, however, some small collateral branches of the cutaneous nerves were found crossing into the “safe” zone . The close relationship of the IER with surrounding nerves is still a critical point to consider when performing a modified Broström-Gould procedure . According to Guelfi et al’s study, compared with arthroscopic all-inside repair techniques, a higher rate of neuritis was encountered in the arthroscopic-assisted technique . So, the key point for avoiding nerve injuries is performing all procedures under direct visualization. In the present study, the absence of nerve injuries could also be explained by the all-inside procedures.
Finally, tightness of the subtalar joint after reinforcement of the IER to the lateral malleolus is still a concerning issue . Recent anatomical and biomechanical researches have noted that the augmentation of the IER can provide a similar outcome to that of the calcaneofibular ligament (CFL) in stabilizing the subtalar joint [4, 31]. According to long-term research of arthroscopic-assisted Broström-Gould repair, no obvious limitation of eversion, inversion and degeneration of the subtalar joint was encountered . In the present study, only 3 female cases complained about irritation around the released site of the IER at the early stage due to the keloid formation. Fortunately, after six months postoperative without a second intervention, this problem was noticeably relieved. Also, no recorded stiffness and degeneration of the subtalar joint was encountered in our cases at the final follow-up (Fig. 6D). As mentioned previously, the appropriate tension of the attached IER could avoid tightness of the subtalar joint.
There are several limitations in this study. First, the sample size is relatively small. Second, it remains to be expounded due to the lack of a control group. Third, this is a preliminary report because of a relatively short follow-up time. Clinical trials are needed to further confirm the results in a long-term postoperative period. Additionally, it is difficult to ask every patient to have the stress radiograph in the department of radiology at each follow-up. So, the stress test was performed and evaluated in the department of orthopedics using fluoroscopy. Finally, those special cases with an absent ATFL remnant (Type-4) were not included in this present study. This study still provides useful insight into the clinical efficacy of the all-inside arthroscopic Broström-Gould procedure.