Introduction
When Bankart originally described anterior glenohumeral instability, he described the labral tear as the essential lesion which was present in over 90% of cases. More recently, however, we have recognized the increasing role of bony anatomy in shoulder stability. Defects, such as glenoid bone loss or a Hill–Sachs lesion of the humeral head, can significantly compromise stability and may compromise the results of labral repair procedures.
Consequently, there has been recently been renewed interest in glenoid-restoring procedures, such as the Latarjet procedure. Originally described by French thoracic surgeon Michel Latarjet in 1954, this involves transfer of the coracoid process to the anterior margin of the glenoid via screw fixation. Later modified by Didier Patte and Gilles Walch, the modern-day Latarjet procedure consists of a 2-cm long coracoid osteotomy, transfixion of the coracoid to the anteroinferior glenoid with two screws, and subsequent repair of the coracoacromial ligament to the glenohumeral capsulolabral complex. Patte proposed that the mechanism of action of the Latarjet procedure only partially owed its success to the bony augmentation of the anteroinferior glenoid. He termed this the triple effect:
- 1)
The dynamic sling of the conjoint tendon that acts upon the anteroinferior capsule and subscapularis, particularly in abduction and external rotation
- 2)
The bony effect of increasing glenoid surface area
- 3)
The ligamentous effect of the repaired anterior capsule to the stump of the coracoacromial ligament
Yamamoto and colleagues recently confirmed this and found that the dynamic sling is the main stabilizing mechanism of the Latarjet procedure.
Several further variations of this basic technique have been published recently, including rotating the coracoid process onto the glenoid, termed the “congruent-arc” technique, intra- versus extraarticular placement of the coracoid, as well as several arthroscopic techniques. Currently, the Latarjet procedure is being performed for a wide variety of indications, including symptomatic primary instability with or without bone loss, recurrent instability with bone loss, and revision surgery.
Regardless of technique variation, there are several principles to the procedure that, if not followed, may result in complications. This includes poor patient selection with inadequate surgical indication, technique-based complications, and issues with postoperative rehabilitation. Although the Latarjet procedure is usually successful, the overall complication rate based on a recent systematic review is approximately 15%. Reported complications include neurological complications, infection, hematoma formation, fracture or nonunion of the coracoid graft, arthritis, and recurrence of instability.
Of particular note are complications regarding the coracoid bone block, as this can significantly impact the outcome of the surgery. Risk of recurrence and long-term outcomes depend strongly on the correct handling and positioning of the graft. Positioning the graft too medially will result in increased rates of postoperative instability, whilst positioning it too laterally will increase the risk of postoperative osteoarthritis. Intraoperative fracture of the bone block is also a significant concern, as this can jeopardize the ability to complete the procedure.
The purpose of this chapter will be to review the potential complications of the Latarjet procedure, including preoperative and patient factors, intraoperative technical issues, and postoperative events.
Preoperative Factors
The Latarjet procedure is not a panacea for all shoulder instability problems. Careful patient selection is paramount to success, and contraindications to the procedure do exist:
- 1)
Anterior instability in the setting of a massive irreparable rotator cuff tear
- 2)
Age greater than 50 years
- 3)
Voluntary anterior dislocators
- 4)
Uncontrolled seizure disorder
- 5)
Chronic locked anterior dislocation
Anterior Instability in the Setting of a Massive Irreparable Rotator Cuff Tear
This clinical scenario is typically encountered in the older patient who presents with a chronically unstable or frankly dislocated glenohumeral joint. It is absolutely critical to evaluate the reparability of the rotator cuff with preoperative imaging, including determining the size and retraction of the tear and degree of rotator cuff muscle fatty infiltration.
It is possible to manage patients with combined Latarjet and rotator cuff tear when the tear is repairable. Walch and colleagues have reported successful combined open rotator cuff tear repair of the supraspinatus and Latarjet using the same surgical incision.
When the rotator cuff is not reparable, particularly the subscapularis, the Latarjet procedure is contraindicated. In this setting, Walch has recommended isolated stabilization with the Trillat procedure. The Trillat procedure is done by performing a closing wedge osteotomy at the base of the coracoid, rotating it laterally, and then screwing the tip of the coracoid to the inferior glenoid. Although it has restored stability in 86% of patients, rotational coracoid osteotomy has been associated with a 65% rate of osteoarthritis. , Should this fail, reverse shoulder arthroplasty is the only possible surgical intervention.
Age Greater Than 50 Years
Age-related bone loss and soft tissue stiffness may contribute to difficulties in performing the Latarjet procedure in patients above 50 years old. Although there is little evidence to support these claims, some authors have observed several types of complications. Primarily, owing to poor bone quality, there may be increased risk of bone block fracture or nonunion. Static anterior instability of the humeral head has been described because of anteroinferior subluxation and progressive osteonecrosis of the head in contact with the graft ( Fig. 26.1 ). Additionally, there may be postoperative irreducible inferior subluxation of the humeral head ( Fig. 26.2 ). This is thought to occur via the nonelastic portion of the subscapularis that is pulled down by the transferred coracoid process and conjoint tendon that results in permanent humeral head subluxation.
Voluntary Anterior Dislocators or Subluxators
Capsular laxity will not be corrected by the Latarjet procedure. Published results are limited but are generally considered unsatisfactory. This is considered a strong contraindication.
Uncontrolled Seizure Disorder
The transferred coracoid process with two screws is insufficiently strong to withstand the strong and violent contraction of the subscapularis during a seizure. Typically, postoperative seizures can result in fracture of the coracoid bone block and 90-degree bending of the screws ( Fig. 26.3 ). Redislocation rates have been reported to be as high as 45%. Revision surgery in these redislocators includes iliac crest bone block transfer. It has been recommended that the primary treatment of instability in these patients is control of their epilepsy. Only once their neurological condition is well controlled should surgery be considered and only in the setting of symptomatic instability with activities of daily living.
Chronic Locked Anterior Dislocation
Typically, a locked, chronic anterior dislocation results from trauma, seizure, or massive rotator cuff tear. A multitude of surgical options have been described, including arthroscopic Bankart repair, Latarjet procedure, bone-grafting, and arthroplasty. Given that this is a rare condition, most studies are case reports or small case series. In our experience, chronic anterior dislocations should not be treated with a Latarjet procedure, owing to the difficulty with achieving stability and the risk of redislocation, humeral head osteonecrosis, and late-onset osteoarthritis. Reverse shoulder arthroplasty is recommended in the elderly patient.
Intraoperative Complications
Coracoid Graft Malposition
Correct positioning of the coracoid bone graft cannot be overemphasized. Ideally, the coracoid bone block should be placed just below the equator of the glenoid and flush with the articular surface. Given this, it is possible that the graft may be placed too medial, too lateral, too inferior, or too superior to this ideal position ( Fig. 26.4 ).
The high incidence of malpositioned grafts has been recognized since the early 1980s, when Hovelius and colleagues reported a rate of 63%. Walch and colleagues found inaccurate graft position in 20% of procedures performed by a single expert surgeon. A more lateralized position was found in 13% of these patients, and in 7% the graft was placed too medially. Medialization greater than 10 mm from the glenoid rim is a critical error that can result in rates of recurrent instability beyond 80%, owing to loss of the bone block function. Grafts placed too laterally significantly increase the risk of osteoarthritis. More recently, Barth et al. considered that the graft position was “medially placed” when it was greater than 4 mm medial and laterally placed when it was greater than 1 mm lateral to the joint line in the axial plane of a computed tomography (CT) scan.
Grafts placed too superiorly can result in both recurrent instability and suprascapular nerve (SSN) injury by the drill or screws ( Fig. 26.5 ). Grafts placed too inferiorly can result in fibrous union owing to a lack of bony contact and likely poor purchase of the inferior screw causing a rotationally unstable graft.
There are likely several causes for malpositioning of the graft. The exposure is relatively small, and it is difficult to completely visualize the glenoid. Additionally, it is technically difficult to grasp, then prepare a relatively small bone fragment and achieve precise positioning. Consequently, parallel drill guides have been developed (Arthrex, Naples FL) that simultaneously hold the graft and allow for drilling of pins to provisionally position the graft onto the glenoid. Barth and colleagues have recently evaluated the use of this guide in a cohort study and compared it to the freehand technique, both performed by expert surgeons. The freehand technique was found to be significantly worse, resulting in more superiorly and laterally placed grafts compared with the parallel drill guide technique. When using the drill guide, it is vitally important to use it appropriately in a perfectly perpendicular fashion. It is possible to become rotationally disoriented and cause the graft to be obliquely oriented. Other available guides with offsets were designed for use with the congruent-arc modification.
Alternatively, Walch has coined the 7-mm rule, where the inferior drill hole should be placed 7 mm medial to the glenoid margin at the 5-o’clock position. In a clinical study, he demonstrated that following the 7 mm rule is anatomically accurate and can prevent lateral graft placement.
Coracoid Graft Fracture
Graft fracture has been reported to occur in 1.5% of cases. There are several causes for intraoperative graft fracture ( Fig. 26.6 ):
- 1)
Overtightening of the screws and failure to use the “two- finger” screw tightening technique with a screwdriver.
- 2)
Excessive decortication of the undersurface of the coracoid causing weakness of the graft. The average thickness of the coracoid is approximately 9 mm.
- 3)
Failure to maintain an adequate bone bridge between the two screws. Some authors find the parallel drill guide (Arthrex, Naples FL) significantly aids in preventing this complication.
