Lateral Patient Positioning for Shoulder Arthroscopy

Abstract

Diagnostic shoulder arthroscopy or arthroscopic shoulder stabilization procedures can be performed with the patient in the beach chair (BC) or lateral decubitus (LD) position. Patient positioning may be dictated by surgeon preference or the specific intended procedure; however, LD setup has been found to result in lower rates of recurrent instability in cases of anterior arthroscopic stabilization procedures. The lateral and axial traction provided by the LD setup allows for lower suture anchor placement on the anterior-inferior aspect of the glenoid, as the surgeon has increased visualization and working room within the glenohumeral joint. Prior to placing the patient in the LD position, meticulous care must be taken to properly position the beanbag device and set up the lateral traction device. Next, a coordinated team approach should be used to roll the patient into the LD position and to ensure that all bony prominences are adequately padded. The shoulder is then placed in 40° of abduction, 20° of forward flexion, with 10-15 pounds of balanced traction. Finally, the shoulder is prepped and draped in the usual sterile fashion and the surgeon is then able to proceed with the necessary arthroscopic procedure.

Case Overview

Background

Anterior glenohumeral joint instability remains a challenging pathology to address, namely in the young and highly active patient population. In most cases of anterior instability, avulsion of the anteroinferior labrum and the capsular attachments from the glenoid rim (Bankart tear) is present in the 3-6 o’clock position, which commonly results from an impaction force with the shoulder in a hyperabducted and externally rotated position.^1,2 Bankart tears can be repaired through a variety of operative techniques, and although open repairs have long been the gold standard for anterior shoulder stabilization, recent reports in the literature demonstrate no significant difference in patient outcomes between open and arthroscopic techniques.^3-7 However, it is important to note that despite considerable advancements in surgical techniques and instrumentation, rates of recurrent instability following Bankart repair remain relatively high, ranging from 10% to 30% and worse in patients returning to overhead, contact or collision sports.^8-10

Focused History of Patient

The patient is an active 18-year-old female, who denies acute injury, but has had chronic anterior shoulder pain of her right shoulder over the past 2 years and has attempted physical therapy for close to 1 year without any signs of improvement. Relevant to this patient’s history is that she has been a high-caliber volleyball player since a young age, which suggests that her chronic glenohumeral joint pain and recurrent anterior instability are most likely due to the repetitive microtrauma experienced in the hitting shoulder by overhead-hitting athletes. The patient is otherwise healthy and has had no prior injuries to the shoulder, nor did she report any incidents of instability in her contralateral shoulder.

Focused Physical Exam

Upon primary physical examination, the patient is a well-appearing female and is neurovascularly intact with no findings of diminished strength of the deltoid and rotator cuff muscles in her right shoulder. She reports 3 dislocation/subluxation events as well as significant apprehension and physical limitations due to these recurrent instability events. She has symptoms consistent with grade II instability (greater than 50% translation with spontaneous reduction) as well as a positive inferior sulcus sign (grade II) and positive relocation test. Physical examinations such as the anterior apprehension test, sulcus sign, relocation test, and load and shift test have demonstrated high sensitivity and specificity in the assessment of anterior shoulder instability, which can significantly aid a surgeon’s preoperative assessment and treatment algorithm.¹¹

Imaging

A standard radiographic shoulder series (AP/Grashey/Axillary/Scapular Y) is obtained, which upon review demonstrates a well-reduced glenohumeral joint with a well-defined sclerotic line of the anterior glenoid and a normal acromiohumeral distance. There is no discernable anterior glenoid bone loss nor is there an obvious Hill-Sachs lesion present. An MRI without contrast of her right shoulder demonstrates a significant anterior labral tear from the 2 o’clock to 6 o’clock position with no evidence of damage to the biceps tendon or rotator cuff.

Natural History

Bankart tears develop as a result of anterior glenohumeral dislocation or subluxation and therefore it is imperative to understand the relevant risk factors that may predispose patients to experiencing these instability events. Young male athletes participating in contact or collision sports (football, rugby, wrestling) have been identified to be at the greatest risk of traumatic glenohumeral instability as they are more susceptible to high-velocity impacts and repetitive movements/positions compared to non-contact athletes.¹² When reviewing the history of a patient presenting with complaints of anterior instability, it is important to note the underlying pathomechanics of their respective injury, the number of instability events following initial dislocation/subluxation, the time between dislocation and reduction (if applicable), and to identify any pre-existing hyperlaxity. These clinical findings can greatly aid the development of a surgeon’s treatment algorithm and preoperative planning strategies for the management of anterior instability and associated Bankart tears.

Options for Treatment

When a patient’s focused history, physical exam findings, and imaging findings indicate the need for an arthroscopic Bankart repair to be performed, the surgeon’s preoperative planning and treatment algorithm must address optimal patient positioning based on the extent and location of the Bankart tear. Although positive clinical outcomes have been reported following arthroscopic Bankart repair in both the Beach Chair (BC) and Lateral Decubitus (LD) setups, repairs performed with the patient positioned in a Lateral setup have demonstrated significantly lower rates of recurrent instability following operative treatment.²

Rationale for Treatment

When performing arthroscopic shoulder stabilization in the LD position, one of the most significant benefits over the BC position is that the surgeon has increased working space as well as visualization within the glenohumeral joint due to the traction provided by the LD positioner.¹³ Moreover, the surgeon will have enhanced access to the 6 o’clock position of the glenoid as well as to the inferior and posterior labrum, inferior capsule, subacromial space, and articular side of the rotator cuff.¹⁴

Discussion

Diagnostic shoulder arthroscopy or arthroscopic shoulder stabilization procedures can be performed with the patient in the BC or LD position. Patient positioning may be dictated by surgeon preference or the specific intended procedure and each position carries its inherent advantages and disadvantages. The BC position allows for easy anatomical orientation of the shoulder, provides excellent visualization of the subacromial space and requires minimal equipment and setup time; however, positioning the patient requires multiple team members, and the BC position does not provide optimal access to the inferior and posteroinferior aspect of the glenoid.^13,15-17 Although the LD setup requires additional equipment and more intensive training to perform arthroscopic procedures, it avoids many of the complications associated with the BC position, as it allows for greater anterior, inferior and posterior glenoid access and visualization, as well as increased working space within the glenohumeral joint.^13,18

Although there is limited available literature that directly compares patient outcomes in the LC versus BC positions for arthroscopic shoulder stabilization, multiple studies have reported outcomes for each separately.^2,19-24 A recent systematic review of 64 studies by Frank et al.² revealed that the BC position has associated rates of recurrent instability of 14.65 ± 8.4% (range, 0% to 38%) following arthroscopic anterior stabilization compared to 8.5% ± 7.1% range, 0% to 30% in the LD position (p = 0.002). However, there were no significant differences reported between the two positions in regard to postoperative loss of range of motion. One explanation for the discrepancies in rates of recurrence between the 2 patient positions is that operative success depends on the surgeon’s ability to place an adequate number of anchors on the anterior inferior glenoid rim in order to provide capsular tensioning. As the most common zone of injury in cases of anterior instability is in the anterior-inferior portion of the glenoid and labrum, the surgeon and overall outcomes of the procedure may benefit from the increased 3 to 6 o’clock access provided by the LD position.²⁵ Further studies that directly compare outcomes in either the LD or the BC position are required in order to decisively determine optimal patient positioning for arthroscopic anterior stabilization.

Equpiment

• Arthrex Shoulder Suspension System
• 1015 U-Drapes, Ioban Drapes, and rectangular drapes
• Circular head pad, axillary roll and bean bags
• Standard shoulder arthroscopy set

Disclosures

Matthew T. Provencher has the following disclosures to report: Is a paid consultant for Arthrex and the Joint Restoration Foundation (Allosource); receives intellectual property royalties from Arthrex; receives publishing royalties from SLACK Inc; is an editorial or governing board member for Arthroscopy, Knee, Orthopedics, and SLACK Inc; and is a board or committee member for AANA, AAOS, AOSSM, ASES, ISAKOS, the San Diego Shoulder Institute, and the Society of Military Orthopaedic Surgeons.

All other authors (L.A.P. and Z.S.A.) have no disclosures to report.

Statement of Consent

The patient referred to in this video article has given their informed consent to be filmed and is aware that information and images will be published online.