Rockwood Adults CH34

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CHAPTER 34 • Glenohumeral Instability

Arthroscopic or open repair is recommended with < 20 degrees of glenoid retroversion and < 20% of glenoid bone loss. In patients with > 20 degrees of retroversion and > 20% of bone loss, a posterior bone block procedure in addition to posterior labral repair is recommended which can be done arthroscopically or open. In the subset of patients with > 20 degrees of retroversion and < 20% of glenoid bone loss, both arthroscopic or open repair with and with- out block procedure should be considered based on the patient’s activity level, presenting symptoms, and expecta- tions. There is paucity of high-quality literature available Postoperative Care The patient is placed in an external rotator immobilizer to pro- tect the posterior repair for 6 weeks. Avoid forward flexion with the arm adducted across the midline in the acute phase after surgery. In phase I between 2 and 6 weeks, the patient stays in the ER immobilizer with elbow and wrist ROM and pendulums. In phase II between weeks 6 and 12, the patient will start pas- sive ROM and progress to active ROM. The authors recommend starting the passive ROM in the supine position without pain. Limit internal rotation and adduction of the arm. Mild strength- ening program is started around 10 to 12 weeks after surgery. In phase III between weeks 12 and 18, the patient progresses to full ROM and isokinetic strengthening. An activity-specific plyometrics program is also started along with sport-specific related programs. Return to sports or high-demand labor jobs typically takes 6 to 9 months after surgery. Potential Pitfalls and Preventive Measures

to direct management of posterior shoulder instability, especially when deciding between arthroscopic and bone block procedures. The authors do prefer the arthroscopic technique over the open technique for posterior stabiliza- tion in the subset of patients with < 20 degrees of retrover- sion and < 20% of bone loss. In the patients with > 20% of glenoid bone loss and > 20 degrees of retroversion, the authors prefer open posterior glenoid bone grafting with iliac crest autograft and capsular labral repair with either arthroscopic technique or open technique depending on the patient, anatomy, and exposure. Outcomes Historically, posterior shoulder instability was treated with open repair, but with the advent of improved arthroscopic tech- niques, implants, and instrumentation, arthroscopic posterior capsulolabral repairs are increasingly common. The difficulty and added surgical morbidity of open repair further diminish its popularity in favor of arthroscopic techniques. A meta-analysis comparison of open versus arthroscopic posterior labral repairs found a 19% recurrence rate of posterior instability while the arthroscopic repair recurrence rate was 8%. 59 The largest series published includes 200 arthroscopic posterior labral repairs on athletes whom experienced a 90% return to play. 29 While glenoid dysplasia and increased glenoid retroversion have been identified as risk factors for the development of posterior shoul- der instability, 69,174 the effect of increased retroversion and gle- noid dysplasia does not appear to have an effect on outcomes. 28 Kim et al. 119 evaluated the outcome after arthroscopic labral repair and posterior capsular shift in 27 patients with traumatic unidirectional recurrent posterior subluxation and reported that all patients were able to return to preinjury sport activities with little or no limitations. Shoulder function was graded as > 90% of the preinjury level in 24/27 (89%) patients. The average pain score decreased from 4.5 points to 0.2 points postoperatively with no operative complications. Wil- liams et al. 265 reported similar outcomes in 27 patients after arthroscopic posterior repair in patients with traumatic pos- terior shoulder instability. At a mean follow-up of 5.1 years, no patients demonstrated a ROM deficit. Symptoms of pain and instability were eliminated in 24/27 patients (89%) with two patients (8%) requiring additional surgery for recurrence of symptoms. In the athletic patient population, Bradley et al. 28 reported 89% of their patients were able to return to sports after arthroscopic posterior labral repair while only 67% of the patients were able to return to their preinjury sport levels. Despite the overall excellent functional outcomes and low fail- ure rates reported in the literature, Radkowski et al. 186 found that throwing athletes were less likely to return to their prein- jury level of sport (55%) compared with nonthrowing athletes (71%). DeLong et al. 59 in a systematic review and meta-analy- sis of clinical outcomes of posterior shoulder instability found that arthroscopic repair is shown to be an effective and reliable treatment for unidirectional posterior shoulder instability with respect to the outcome scores, patient satisfaction, and return

Posterior Glenohumeral Instability: SURGICAL PITFALLS AND PREVENTIONS Pitfall Prevention

• Aberrant portal placement

• Use a standard posterior lateral accessory arthroscopic portal established parallel to glenoid articular

surface. The drill guide should be parallel to the spine of the scapula

• Poor angle for anchor insertion • Inability to visualize posterior-inferior labrum and capsule in beach chair position

• Use percutaneous technique and independent posterolateral portal

• Use lateral position with axillary roll/ bump • External rotation of the arm will help open the posterior capsule to allow space to work in the back to repair the labrum • If the posterior working portal is above the labral tear, use the curved guide that is opposite of the operative extremity (right curve for left shoulder and vice versa). If the posterior working portal is at the level of the labral tear, then use the 90-degree passer to assist in the shuttling of the sutures

• Difficulty with

passing the suture