Example of the on/off track scenario
5.2.7 Instability Severity Index Score (ISIS)
Prognostic factors | Points |
|---|---|
20 years old or younger | 2 |
Competitive sports | 2 |
Contact or forced overhead sports | 1 |
Shoulder hyperlaxity (anterior or inferior) | 1 |
Hill-Sachs lesion on AP radiograph visible in external rotation | 2 |
Glenoid loss of contour on AP radiograph | 2 |
Total (points) | 10 |
5.3 Per-Operative Complications (Surgery)
Once a soft tissue repair for shoulder instability is indicated, several factors have to be considered to safely perform the arthroscopic procedure: What is the optimum positioning of the patient? What implants and instruments should be used? How should the soft tissue repair be done in terms of number and placement of anchors? What is the perfect stitch configuration? Numerous problems can occur, most of them will be easy to address but some may even risk the long term outcome of the patient.
One sort of per operative complication may be that the preoperative diagnosis was wrong and the surgeon is faced with an unexpected situation: either the arthroscopic finding is “too good” for soft tissue repair (Buford complex), or the arthroscopic finding demonstrates a worse condition as expected. This might be if there is no capsulolabral soft tissue to be fixed to the glenoid. Informed consent to be able to convert to bony procedure may be a good advice to be prepared for this case.
The following chapter presents proven concepts in the literature that strive to keep the complication rate low.
5.3.1 Positioning of Patient
The arthroscopic stabilization procedure could be performed either in lateral decubitus or in beach chair position. In both excellent results could be obtained and the decision is based more on surgeon experience and familiarity [20].
5.3.2 Surgical Technique (Cases 1, 3, 4)
Through diagnostic arthroscopy the labrum, capsular tissue, rotator cuff, the biceps pulley, the humeral head (Hill-Sachs lesion) and the cartilage should be evaluated. As diagnostic tool a load-shift or a drive-through sign can be performed. For description, the glenoid is described as a clock face. The most inferior aspect of the glenoid represents the 6 o’clock position [21].
After setting the portals, the lesion should be adequately mobilized using an elevator. Also, the glenoid should be debrided and decorticated sufficiently to ensure tissue healing after repair. For the capsulolabral lesion a soft tissue grasper should be used. Visualization of muscle fibers of the subscapularis indicates a sufficient mobilization [21].
A biomechanical study, comparing the simple stitch, suture anchor with horizontal mattress stitch, double-louded suture anchor with simple stitch, and knotless suture anchors could show, that all four constructs displayed less than 2-mm displacement when 25 N cyclic loading was applied. But the knotless construct showed significantly less force to ultimate failure [22]. Ranawat et al. could furthermore show that both knotted and knotless anchors fail most often at the suture-tissue interface [23].
Through the antero-superior portal an arthroscopic grasper can be inserted, which allows reducing the labral tissue and further suture retrieval. For reduction of the Bankart lesion, the anchors were placed from inferior to superior, starting as inferior as possible at the 5:30 or 6:30 position [24]. In cases visualization is restricted, the scope could be inserted in the antero-lateral portal or alternatively a 70° arthroscope could be used. Using a suture passer through the anterior portal, the suture is passed through the avulsed capsulolabral tissue, taking into consideration to capture at least 1 cm of capsular tissue in addition to the labrum [21].
Concerning number of anchors Shibata et al. could show that using less than four anchors were significantly more likely to fail [25]. Boileau et al described that patients with three or less suture anchors, were at a higher risk to fail [26].
5.3.3 Anchor Composition and Design (Cases 2 and 5)
Implant design and material has improved over years. Metal anchors are associated to loosening and migration, could lead to chondral damage and limit further investigation by MRI [27].
Using bioabsorbable anchors, especially made of poly-L-lactic acid (PLLA), complications like inflammatory reaction, osteolysis, and chondrolysis are a known phenomenon. McCarty et al reported in their study, evaluating their results after arthroscopic revision with index surgery using PLLA anchors, in over 50% anchor debris and in 70% a chondral damage [28]. Kim et al. described a 46.4% rate of cyst formation after using bioabsorbable anchors in rotator cuff tears [29].
After development of biocomposite anchors the rate of osteolysis and synovitis has been lowered [30]. Next to the excellent clinical outcome, Milewski et al. described in their study the prevalence of 6.4% cyst formation and the prevalence of 55% tunnel widening [31].
Nonabsorbable biostable anchors are resistant to degradation and osteolysis. However inappropriate positioning or fracture of the material could lead to chondral damage [32].
More recently, all-soft suture anchors were developed for stabilization surgery. Advantages are decreased removal of bone and decreased glenoid volume occupied. Nonetheless, a recent study published by Tompane et al. demonstrated a significantly tunnel increase in volume 6 and 12 months after shoulder labral surgery. The authors could show low rates of cyst formation [33].
5.4 Immediate Postoperative Complications
5.4.1 Nerve Injury
Nerve injury in arthroscopic shoulder stabilization is not seldom. Nonetheless, Owens et al. described the rate of nerve injury in Bankart repair procedure with 0.3% [34]. Most frequently injured is the axillary nerve, due its course anterior to the subscapularis muscle and on the inferior border of the tendon before passing posteriorly into the quadrilateral space [35]. The closest position between the nerve and the glenoid rim is at the 6 o’clock position on the inferior glenoid rim and could be injured by placing anchors, sutures, or repairing capsular lesions [36]. If a nerve injury is suspected, performing of an electromyography (EMG) is recommended. After a period, which is controversially debated in literature between 3 and 6 months, a surgical procedure should be taken into consideration [37].
5.4.2 Infection
Infection rate in arthroscopic Bankart repair is according to Owens at 0.22% [34]. Superficial infections of related to the arthroscopic portal infection or deep intraarticular glenohumeral infection is possible. Therefore, prevention of infection in general, but especially in patients suffering from diabetes or atopic dermatitis, is mandatory [37].
If an infection is suspected, aspiration of the joint is performed and analyzed to confirm the suspected infection. This procedure is followed by oral or intravenous antibiotics. Penicillin-based or cephalosporin antibiotics as the first choice are recommended. They have to be adapted to the microbiological results as soon as available [38]. If infection cannot be controlled, an arthroscopic approach with synovectomy and drainage is recommended. Matsuki et al. do not recommend removal of the anchors unless peri-anchor infection is apparent [37].
5.5 Middle Term Complications
5.5.1 Postoperative Stiffness
Loss of range of movement is a well known complication after shoulder stabilization surgery. In addition to loss of range of movement, it can cause pain and limit activities of daily living. First treatment in these cases is usually physiotherapy. In cases with severe pain, intraarticular injection of a corticosteroid should be taken into consideration. Most patients respond to the conservative pathway. An arthroscopic intervention should be considered after unsuccessful conservative treatment over 6 months, performing an arthroscopic capsular release.
In cases with an isolated loss of external rotation, Ando et al. described an arthroscopic procedure with removal of scar tissue of the rotator interval and release of the subscapularis tendon from the anterior glenoid neck, called restoration of anterior transverse sliding (RATS) [39].
5.5.2 Persisting Pain
A recent review of the American Academy looked at shoulder arthroscopy specific complications. The overall complication rate in patients undergoing labrum repair was nearly 6%. One of the most common complications was persisting pain [40].
5.5.3 Chondrolysis
Chondrolysis is defined by rapid destruction of articular cartilage. Several reasons for initiation or progression are possible. One possible reason is the use of thermal devices, which have been associated with development of chondrolysis [41]. Several recent studies analyzed causation of glenohumeral chondrolysis by postoperative infusion of local anesthetic. They concluded, that the use of postoperative infusion of intraarticular local anesthetic was strongly associated with chondrolysis [42]. According to Sugaya, postoperative injection of local anesthetic through an intra-articular pain pump should be avoided to prevent chondrolysis of the glenohumeral joint. (Matsuki, Sugaya, 2015) Therefore, the use of single postoperative intraarticular injection or the use of intra-articular pain pumps is fallen out of favour.
5.6 Long Term Complications
5.6.1 Osteoarthritis (Case 6)
Previously published studies following Bankart repair reported postoperative rates of osteoarthritis to be as high as 26% [43]. Hovelius et al. published in their study following primary dislocation with a follow-up of 10 years in 11% mild and in 9% moderate or severe osteoarthritis [44]. Franceschi et al. analyzed the pre- and postoperative radiography of 60 patients with an average follow-up of 8 years. They concluded, that the incidence of degenerative joint disease was associated with an older age at the time of the first dislocation and at surgery, increased length of time from the first episode to surgery, increased number of preoperative dislocations, increased length of time from the initial dislocation until surgery, increased number of anchors used at surgery, and more degenerated labrum at surgery [45].
Case 1: Intraarticular Failure of a Suture Passer
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