Neurological Injury

Neurological injury is an uncommon complication of anterior stabilization, but with potentially devastating outcomes to the patient. It has been reported to occur among candidates for the American Board of Orthopaedic Surgery (ABOS) certification examination in 0.3% of arthroscopic anterior labral repairs, significantly lower than a 2.2% rate for open anterior stabilization procedures. The axillary nerve is at greatest risk of neurologic injury during arthroscopic anterior labral repair. It passes adjacent the inferior glenohumeral capsule, closest to the glenoid rim at the 6-o’clock position at an average distance of 1.2 cm. This places the axillary nerve at greatest risk during inferior labral mobilization, anchor placement, and suture passage near the 6-o’clock position. Accessory portal placement with 7-o’clock and 5-o’clock portals requires careful attention to surrounding neurovascular structures, with the axillary nerve reported to be 15 mm inferomedial to the 5-o’clock portal and 39 mm from the 7-o’clock portal. The suprascapular nerve was also 29 mm from the 7-o’clock portal.

Transient traction–related neuropraxia has been reported for 10% to 30% of lateral decubitus shoulder arthroscopies, thought to be because of traction on the brachial plexus and upper extremity nerves. Fortunately persistent neuropraxia is only encountered in very rare situations involving the musculocutaneous and ulnar nerves. Avoiding excessive traction weight and time during surgery is the primary method to avoid this complication, and our experience has been that efficient, reproducible surgical technique allows arthroscopic anterior labral repair to be performed without traction-related neuropraxia in the vast majority of cases. In addition, positioning of the patient’s contralateral arm, neck, and lower extremities must involve careful padding of prominences and placement in comfortable positions to avoid iatrogenic neuropraxia to other parts of the body.

Management of nerve injury involves careful postoperative assessment of neurological function, which is often not possible immediately after surgery because of interscalene block. Particular attention is paid to the axillary nerve. Most cases are neuropraxias that resolve spontaneously. If symptoms do not improve, electromyography (EMG) is obtained at 4 to 6 weeks postoperatively. Symptoms are monitored for 3 to 6 months to evaluate for signs of improvement. In some cases, repeat EMG may be performed to evaluate for signs of nerve recovery. If symptoms fail to resolve, open surgical exploration of the involved nerve can be considered, with possible nerve grafting or tendon transfers depending on the exact nerve injury; however, this is a salvage option with a poor prognosis in our experience.

Anchor-Related Complications

Perhaps the most common complication after arthroscopic anterior labral repair is iatrogenic anchor-related damage to the glenohumeral joint, although the exact incidence is difficult to quantify owing to underreporting. The ABOS data suggest that intraoperative implant failure occurs in 0.3% of cases, although other anchor-related complications are not reported. Early techniques of arthroscopic anterior labral repair with staples or bioabsorbable tacks included up to a 30% rate of implant-related complications. Anchor-related complications include pain, loss of range of motion, implant loosening or failure, glenoid osteolysis, chondrolysis, and synovitis. Poly-L-lactic acid implants were associated with macroscopic intraarticular debris in over half of patients, giant cell reaction in 84% of patients, and high-grade chondral damage in 70% of patients. Advances in surgical technique, as well as meticulous anchor insertion and avoiding prominent anchors, has helped to reduce these complications significantly with modern techniques and implants.

Anchor drilling at or near the 6-o’clock position can result in far cortex perforation, which can result in weaker anchor fixation and compromised labral repair, failure of anchor placement or anchor pull-out attributed to poor fixation, the need for additional drilling to achieve anchor fixation, or potential damage to structures beyond the opposite cortex. Several cadaveric studies have reported that accessory portals including the 5-o’clock transsubscapularis portal enable anchor placement at the inferior glenoid with a lower risk of opposite cortex perforation.

Proper visualization and portal placement are paramount to preventing iatrogenic damage during labral and glenoid preparation, anchor drilling, and anchor placement. We prefer the lateral decubitus position for improved glenohumeral joint distraction by way of balanced suspension that affords better visualization and instrumentation to the inferior glenoid compared with the beach chair position. ^, In addition, we use the accessory 7-o’clock posterolateral and 5-o’clock transsubscapularis portals to facilitate anchor placement and suture passage at the inferior glenoid, allowing a stable repair without perforation of the opposite cortex or iatrogenic damage. ^,

Anesthesia-Related Complications

Anesthesia-related complications have been reported to occur in 0.38% of arthroscopic anterior labral repairs based on ABOS data. Appropriate preoperative patient evaluation can help to medically risk stratify and optimize patients before they undergo elective surgery, which may help to reduce anesthesia-related complications. Hypotensive anesthesia and beach chair positioning have been proposed as potential factors associated with hypotensive episodes and potential decreased cerebral oxygenation. These techniques can be used safely for the vast majority of patients, and evidence suggests that intraoperative cerebrovascular events are extremely uncommon and not clearly associated with patient positioning in the beach chair versus lateral position. ^, Finally, regional anesthesia with interscalene block is effective and safe for pain control during and after arthroscopic anterior labral repair, but there are rare cases of neurologic injury, hematoma, or other complications.

Infection

As with other shoulder arthroscopic procedures, infection following arthroscopic anterior labral repair is uncommon, with ABOS data indicating a rate of 0.22%. Most infections are superficial portal-site infections and resolve with oral antibiotics. Patient risk factors for infection after shoulder arthroscopy include intraoperative steroid injection, revision surgery, obesity, male sex, anemia, malnutrition, depression, diabetes, and alcohol use. Risk factors should be discussed before surgery with the patient during a detailed conversation of risks and benefits of surgery. When possible, risk factors should be modified before elective surgery to reduce risk of infection. Standard surgical principles of infection prevention apply, including skin preparation and sterile draping, as well as preoperative antibiotics. Evidence suggests that ChloraPrep may more effectively eliminate skin bacteria than alternative skin preparations for the shoulder, including Propionibacterium acnes . Emerging research of the usefulness of other topical agents in reducing P. acnes colonization suggests that administration of agents such as benzoyl peroxide and topical clindamycin in the days before surgery may reduce skin colonization, although the effect on postoperative infection rates remains unclear.

For superficial infections, oral antibiotics are used for treatment. Deep infection is suspected when patients experience persistent pain, erythema, drainage, or systemic symptoms such as fever and chills. Laboratory evaluation is undertaken with complete blood count, erythrocyte sedimentation rate, C-reactive protein, and a synovial fluid sample is taken for cell count and culture. Laboratory workup is often negative, and cultures should be held for 14 to 21 days for possible P. acnes . If deep infection is confirmed or suspected, treatment is with arthroscopic irrigation and debridement. Tissue samples are taken for culture to guide antibiotic therapy postoperatively, in consultation with infectious disease specialists. Anchors and sutures are generally retained at the time of irrigation and debridement to protect the labral repair unless the anchor clearly appears to be a source of infection.

General Medical Complications

General medical complications are uncommon but can occur after arthroscopic anterior labral repair, primarily related to patient preoperative comorbidities as well as longer surgical time. Among 15,015 patients undergoing shoulder arthroscopy, Hill et al. found a 30-day readmission rate of 0.98% associated with operative time over 1.5 hours, age over 40, American Society of Anesthesiologists class 3 or 4, the presence of chronic obstructive pulmonary disease, and chronic steroid use. Significant medical complications were uncommon, with pulmonary embolism occurring in 0.13% of patients, myocardial infarction in 0.02%, acute renal failure in 0.01%, stroke in 0.03%, cardiac arrest in 0.01%, deep vein thrombosis in 0.14%, and mortality in 0.01%. Patients undergoing arthroscopic anterior labral repair are younger and healthier than the average shoulder arthroscopy patient undergoing other procedures such as rotator cuff repair, and therefore the rates of general medical complications and readmission following arthroscopic anterior labral repair are likely to be much lower than the rates of Hill et al.’s series, in which only 7% of cases were arthroscopic capsulorrhaphy (29806 CPT Code).

Stiffness

Stiffness can occur after arthroscopic anterior labral repair, although less commonly than it does after other shoulder procedures such as rotator cuff repair. Ahmed et al. reported postoperative stiffness in only 5 of the 302 patients in their series (1.7%), all of which resolved with physical therapy. In cases where remplissage is performed, there may be a slight loss of external rotation, generally 5 degrees or less in recent series. ^, Management of postoperative stiffness involves physical therapy and a home exercise program, which is successful in resolving stiffness in the vast majority of cases. In cases where the patient has significant postoperative pain and stiffness not responding to physical therapy alone, we may use oral or injected corticosteroid. In rare cases where stiffness does not resolve after 6 months of conservative treatment, arthroscopic capsular release could be performed, although we have not had to do this in practice.

Chondrolysis

Chondrolysis of the glenohumeral joint involves rapid cartilage destruction with joint space narrowing, which has been associated with thermal capsulorrhaphy during surgery and intraarticular pain pump postoperatively. Good et al. reported eight cases of glenohumeral chondrolysis, of which five had a history of thermal capsulorrhaphy for diagnosis of instability. Matsen et al. systematically reviewed the published literature on glenohumeral chondrolysis, finding that the “preponderance of cases of glenohumeral chondrolysis can be prevented by the avoidance of the intra articular infusion of local anesthetic via a pain pump.”

Osteoarthritis

Osteoarthritis has been reported to occur in 26% of patients at a mean of 11 years’ follow-up based on a systematic review of 1781 patients and 26 studies. Kavaja et al. reported outcomes of 74 patients at 13 years’ follow-up after arthroscopic anterior labral repair, finding 68% radiographic diagnosis of glenohumeral osteoarthritis, although 80% of those with osteoarthritis were classified as mild, and functional outcomes remained relatively good.

The literature suggests that patient age and the extent of damage from recurrent instability events, rather than surgical treatment, are associated with development of secondary dislocation arthropathy. One study found that risk factors for the development of osteoarthritis were older age at first dislocation and at surgery, increased length of time from first dislocation to surgery, increased number of preoperative dislocations, increased number of anchors used in the repair, and degenerated labrum at time of surgery. Two other studies with 6.5 and 13 years’ follow-up similarly found that osteoarthritis was associated with the number of preoperative dislocations and older age at initial dislocation. ^,

Management of osteoarthritis secondary to shoulder instability involves similar modalities to primary osteoarthritis, including activity modification, physical therapy and home exercise, oral antiinflammatories, periodic cortisone injections, and shoulder arthroplasty if all other measures fail.

Recurrent Instability

Recurrent instability is one of the most significant complications following arthroscopic anterior labral repair. Recurrence rates have been reported to range from 8% to 24% depending on technique, with a rate of 8.5% reported for arthroscopic suture anchor technique. This rate is a significant risk, because recurrent instability often will require a significant modification of activities or a revision surgery, often with an open procedure. In addition, there has been significant interest in recurrence rate of arthroscopic anterior labral repair in high-risk patients, including young contact and collision athletes, who are reported to have rates of failure of 20% or higher.

The instability shoulder index score (ISIS) was proposed as an attempt to predict patients with unacceptable risk of recurrence after arthroscopic stabilization, incorporating patient age, level of sporting participation, contact or overhead sports, shoulder hyperlaxity, and glenoid and humeral bone loss on anteroposterior radiograph. ^, Phadnis et al. suggest that, for an ISIS score of 4 or higher, patients had a 70% risk of failure with arthroscopic stabilization. By contrast, others have suggested that, with modern techniques and careful analysis of copathology including anterior glenoid bone, arthroscopic stabilization can be highly effective. Dickens et al. have reported that, in a group of collegiate American football players who would be considered at high risk of failure, arthroscopic stabilization resulted in no recurrent instability for patients with less than 13.5% anterior glenoid bone loss (47 patients). In contrast, three players had recurrent instability, all of whom had “subcritical” glenoid bone loss ranging from 13.5% to 20%. This has led these authors and others to suggest a lower “critical” threshold of anterior glenoid bone loss closer to 13.5% to 15%, above which there are high recurrence rates after arthroscopic stabilization. ^,

In preoperative planning, we consider patient factors including activity level and contact sports, but also use CT scan with three-dimensional reconstruction to fully evaluate bone loss before proceeding with arthroscopic anterior labral repair. In patients with bone loss identified during preoperative planning, we would consider adjunctive procedures such as remplissage or Latarjet depending on the pattern and degree of bone loss and the glenoid track measurement. ^,

In addition, there is evidence that certain technical pearls may reduce the risk of recurrent instability after arthroscopic anterior labral repair. A metaanalysis by Frank et al. found that arthroscopic anterior labral repair in the lateral decubitus position resulted in lower recurrent instability rates compared with the beach chair position (14.7% vs. 8.5%). Another systematic review from Leroux et al. found that, among 779 contact and collision athletes with a mean age of 19.9 years undergoing arthroscopic anterior labral repair, there was an overall recurrence rate of 17.8%. When they limited results to patients without significant bone loss, repairs using a minimum of three suture anchors, and procedures performed in the lateral decubitus position, the failure rate was significantly improved at 7.9%. Based on these findings and our clinical experience, management of the inferior component of instability pathology is critical to avoiding recurrent instability and is facilitated by the use of lateral decubitus positioning and 7-o’clock and 5-o’clock accessory portals to achieve placement of multiple suture anchors near the inferior glenoid.