4.4 Immediate Post-Operative Complications

Superficial infection following arthroscopic ACJ intervention is described as one of the more common complications occurring in the short-term following surgery. It has been reported to occur in 3.8% of patients, based on a pooled analysis of multiple studies, and may be successfully treated with a short course of oral antibiotics [10]. There are limited reports of superficial infections not resolving with medical management alone, requiring operative removal of hardware and irrigation and debridement of the intra-articular space [19]. Deep infection of the joint is a risk of surgery, however it has not been frequently reported in the literature. Removal of foreign material and debridement of the joint is indicated in all cases of deep infection. General complications of arthroscopy and instrumentations and are covered in other chapters.

4.5 Middle-Term Complications

Loss of fixation following ACJ repair is seen in 26.8% of cases [10]. Complications resulting in poor AC joint reduction on radiographic imaging are more commonly seen following procedures using allograft or autograft tendon alone for chronic ACJ injuries [12]. The average time to loss of reduction on pooled analysis of several studies is 7 weeks, and this loss is more commonly due to suture rupture than to failure of the fixative hardware [10, 20]. While radiographic findings of loss of reduction do not always coincide with clinically poor outcomes, it has been shown that this complication is related to lower scores in the pain and activities subsets of the Constant score assessed post-operatively [11]. Loss of fixation due to rupture of graft or suture allows revision surgery to be performed with a similar technique. When loss of fixation is secondary to button migration through bone, revision options require assessment of the quality of remaining bone (Fig. 4.2). Bone failure or fixation pullout can generally be traced to tunnel malposition and can be avoided by proper adherence to surgical technique. One challenge of arthroscopic ACJ stabilization is that the joint is reduced with a drill guide and the clavicle and coracoid tunnels are drilled together. Proper hole placement with this common technique can be challenging [21]. Use of smaller drill holes or drilling the coracoid and clavicle independently can reduce malposition.

Pain following operative fixation of the AC joint is one of the most commonly reported complications in the literature. There are varying etiologies and underlying factors leading to pain in these patients. Most commonly, local irritation secondary to prominent implants or sutures is bothersome to patients and reported to occur in 25–39% of cases [11, 19, 22]. Pain may also be secondary to inadequate restoration of anatomy during repair. Over, under, or loss of reduction of the ACJ is common. With improper placement of suture or graft, either during non-anatomic reconstruction or with poor placement of bone tunnels, vertical stability may be restored while anterior-posterior instability remains [23] (Fig. 4.3).

Calcification of the CC ligament remnants is another frequently observed complication following surgical repair of AC joint injuries. It occurs in 31.6% of cases [10], presenting within 6 months of the procedure and remaining stable following this time point. For calcification incidentally noted on radiographic exams, no intervention is required. Although infrequent, calcification causing pain or limiting motion may require excision. Care must be taken not to disrupt the repair of the index procedure during excision of the calcified ligaments.

4.6 Long-Term Complications

Literature reporting on the long-term complications following arthroscopic repair and reconstruction of the ACJ is very limited. The most common complications seen several years removed from surgery are loss of reduction and hardware failure. Distal clavicle osteolysis or ACJ arthritis can be seen as a long-term consequences of these injuries and surgical procedures. These conditions arise from repetitive micromotion at the AC joint and generate pain for the patient. Treatment includes activity modifications, NSAIDs, injections, and distal clavicle excision.

Perhaps the most challenging and poorly understood complication is horizontal instability. Most described techniques for ACJ repair involve only CC stabilization. These procedures may not reliably restore horizontal stability. At minimum, to prevent horizontal instability the distal clavicle should be preserved and not routinely removed [24]. Additionally, the ACJ ligaments should be repaired. In the failed or chronically unstable ACJ with horizontal instability, the surgeon should consider direct repair, device stabilization, or graft augmentation of the ACJ ligaments [25].

4.7 Conclusion

As we gain better understanding of complications, the surgeon can better avoid these potential issues with proper mastering of the technical aspects of surgical reconstruction. Pre-operative assessment and planning is a crucial stage in the treatment of complications arising from arthroscopic repair and reconstruction of the ACJ. Identification of the mode of failure is essential as it allows for a strategic approach to address both the original injury and the complicating factors surrounding the unsuccessful index procedure. The restoration of a stable, functional, pain-free shoulder remains the overall goal of surgical intervention at the ACJ. Developing a good working knowledge and skill set of the techniques described in this chapter will aid the surgeon managing these difficult injuries.