Percutaneously Assisted Posterior Capsulorrhaphy for Persistent Posterior Humeral Subluxation in Shoulder Arthroplasty

Soft tissue balancing in arthritic shoulders with fixed posterior subluxation is a significant challenge when performing anatomic total shoulder arthroplasty (TSA) or hemiarthroplasty. In these cases, chronic posterior subluxation of the humeral head on the glenoid is associated with significant soft tissue derangement and predisposes patients to continued decentering.1 When this is left unaddressed, persistent humeral head subluxation and decentering may increase the risk of glenoid component failure through eccentric edge-loading, rocking horse micromotion, and accelerated polyethylene wear.1,2 Several approaches to soft tissue balancing during anatomic total shoulder arthroplasty have been described, including the use of augmented glenoid components, anterior eccentric heads, thicker humeral head components, glenoid bone grafting, rotator interval plication, modified postoperative restrictions, and even reverse shoulder arthroplasty (RSA).3,4 One additional technique is posterior capsulorrhaphy, which relies on tightening the posterior capsule to restore humeral head centering within the glenoid to enhance the overall stability and function of anatomic total shoulder arthroplasty or shoulder hemiarthroplasty.2 Various open and arthroscopic techniques for posterior capsulorrhaphy in the setting of native shoulder instability have been described, such as plication of the capsule, infraspinatus splitting approach, anterior approach, or single portal capsulorrhaphy using suture anchors or metal staples. In the present report, we describe a novel, easily reproducible method of conducting a posterior capsulorrhaphy during shoulder arthroplasty with the use of an accessory percutaneous portal in combination with the traditional open delto-pectoral approach. TECHNIQUE Indications and Contraindications Posterior capsulorrhaphy is indicated for patients with persistent intraoperative posterior capsule laxity, inadequate humeral head centering, or difficulty seating the glenoid component during implant trialing. This technique is ideally applied in cases of mild-to-moderate posterior humeral head decentering, which is persistent during intraoperative soft tissue balancing. Anatomic constraints, including small glenoid vaults or compromised bone quality, may also prompt capsulorrhaphy. If head recentering is insufficient, anterior eccentric humeral heads or RSA may be considered. Preoperative imaging can be used to assess the severity of posterior humeral head subluxation and glenoid retroversion (Fig. 1).FIGURE 1: (A-C) Preoperative radiographic imaging (anterior-posterior, scapular-Y, and axillary views) demonstrates severe glenohumeral joint osteoarthritis, Walsh B2 glenoid, and posterior humeral head subluxation in the setting of a healed displaced posterior glenoid fracture. (D) Axial views on preoperative computer tomography scans show ∼28 degrees of retroversion and roughly 67% posterior humeral head subluxation. Humeral head subluxation is measured in relation to the glenoid articular surface as described by Matsen and Hsu.1 (E) A T1 sagittal cut on magnetic resonance imaging (MRI) demonstrates healthy rotator cuff muscles. (F) A proton density fat-saturated axial MRI cut demonstrates chronic degeneration of the posterior labrumRelative contraindications include severe glenoid retroversion, extensive posterior bone loss requiring osseous correction, irreparable rotator cuff tears, and significant posterior capsule stiffness. In the setting of revision TSA or conversion of failed fracture surgeries, RSA may be a more reliable option as posterior capsulorrhaphy has been associated with high failure rates during these procedures.3,5 Ultimately, the decision to perform posterior capsulorrhaphy is made intraoperatively when persistent posterior translation or inadequate humeral head centering is observed despite standard component positioning and trialing. Patient Positioning and Anesthesia Following an interscalene block and sedation, the patient is positioned in a beach chair, and bony landmarks are padded. The arm is prepped and draped in the usual sterile fashion. Initial Approach, Glenoid Preparation, and Humeral Trialing The procedure is performed through a standard deltopectoral approach, taking care to preserve the coracoacromial ligament, which acts as a secondary restraint to humeral head decentering in the coronal and sagittal planes. The subscapularis can be managed through a lesser tuberosity osteotomy (senior author’s preference), peel, or tenotomy. After humeral capsular release and humeral head osteotomy, glenoid preparation includes excision of the labrum and superior biceps, except in hemiarthroplasty cases. In patients with posterior subluxation, 360-degree glenoid release may exacerbate posterior laxity, and anterior capsulotomy or capsulectomy may be performed instead. Standard glenoid sizing and instrumentation are completed. During humeral trialing, anatomic head sizing, soft tissue-based techniques, or head eccentricity are prioritized to avoid overstuffing with thicker humeral head components. Patients with persistent intraoperative humeral head subluxation are indicated for posterior capsulorrhaphy. Posterior Portal Creation After humeral head osteotomy, a posterior portal is created using an inside-out technique. An arthroscopic switching stick is passed posteriorly through the capsule and deltoid muscle and visualized subcutaneously over the posterior shoulder. A small skin incision is made directly over its position. Care is taken to ensure the switching stick level is superior to the axillary nerve. A dilator and arthroscopic cannula (Twist-In Cannula, Arthrex, Naples, FL) are inserted over the switching stick to establish portal access (Fig. 2).FIGURE 2: (A) An arthroscopic switching stick is inserted from the inside of the shoulder joint, passing through the posterior capsule and deltoid muscle. The tip of the switching stick is visualized posteriorly, and a small skin incision is made directly over its position. (B) A dilator and then an arthroscopic cannula are inserted over the switching stick into the joint to provide stability for the portal during the procedure. (C) A lamina spreader is placed against the humeral head and glenoid face to aid in visualization of the posterior capsule. (D) The anchor guide is passed into the joint through the posterior cannula. (E) The anchor can then be placed onto the posterior glenoid rim. (F) One limb of the suture from the anchor is retrieved through the anterior aspect of the joint using a grasper. A suture lasso is introduced through the posterior cannula, and the posterior capsule is pierced with the suture lasso. The lasso is then retrieved through the front of the shoulder joint. (G) The retrieved limb of the anchor suture is shuttled through the posterior capsule with the suture anchor and passed through the loop of the shuttle stitch. The knotless system is tightened, pulling the capsule taut against the glenoid rim.Anchor Placement Under indirect visualization from the anterior deltopectoral incision, the anchor guide is passed into the joint through the posterior cannula, and the anchor is placed onto the posterior glenoid rim. A Hintermann retractor or laminar spreader may be used to assist in capsule visualization (Fig. 2). Anchor selection is surgeon-dependent and unlikely to impact outcomes. The senior author prefers all 1.8 mm knotless suture anchors (Arthrex, Naples, FL). Knotless Anchor Suture Management and Posterior Capsule Tightening A single repair suture from the anchor is retrieved through the anterior aspect of the joint. Under direct visualization through the deltopectoral approach, a suture lasso, introduced through the posterior cannula, is pierced through the posterior capsule and retrieved anteriorly. The retrieved limb of the anchor suture is shuttled through the posterior capsule with the suture lasso and passed through the loop of the shuttle stitch. The knotless system is then tightened, pulling the capsule taut against the glenoid rim (Fig. 2). Tension on the posterior capsule is carefully adjusted to center the humeral head within the glenoid without restricting motion. Knotless anchors can be sequentially tightened and retightened as needed. Additional anchors may be placed as needed along the posterior capsule. It is crucial to avoid drilling into glenoid component pegs. In addition, when creating the portal, it is important to envision the approach of the drill guide and anchors to the glenoid rim. A portal that forces the drill guide and anchors into an acute angle may lead to slippage on the glenoid edge. A curved drill guide can be used to mitigate a suboptimal portal trajectory. Completion of the Shoulder Arthroplasty Final implants are carefully placed, avoiding excessive internal rotation. The shoulder joint is assessed using the “40-50-60” rule (40-degree external rotation, 50% posterior translation, 60-degree internal rotation at 90-degree abduction). Intraoperative fluoroscopy is used to confirm adequate component positioning and humeral head centering throughout motion (Fig. 3). If necessary, an anteriorly eccentric humeral head, final capsulorrhaphy tightening, or a rotator interval plication may be performed to further balance persistent posterior laxity.FIGURE 3: Intraoperative anterior-posterior and axillary views are used to confirm adequate component positioning (Tornier Perform, Bloomington, MN) and humeral head centering throughout motion.A FiberTape (Arthrex, Naples, FL) is wrapped around the humeral head/taper junction, and the head (Tornier, Bloomington, MN) is impacted onto the taper in an anterior eccentric fashion. The joint is thoroughly irrigated, any loose tissue is removed, and the subscapularis is repaired incorporating the wrapped FiberTape. Postoperative Care Postoperatively, the shoulder is immobilized in slight external rotation and neutral abduction using a gunslinger brace or an abduction pillow. After initial immobilization, gentle range-of-motion exercises are begun, focusing on motion in the scapular plane, with gradual progression to strengthening exercises. Regular follow-ups are scheduled to monitor posterior capsule healing and shoulder joint stability. Expected Outcomes We hypothesize that percutaneously assisted posterior capsulorrhaphy is an effective adjunct for recentering the humeral head and improving posterior stability in patients with posterior humeral head subluxation undergoing TSA and hemiarthroplasty. By restoring humeral head centering, this technique may reduce eccentric loading on the glenoid component and improve functional outcomes. A similar alternative technique, posterior plication, during anatomic total shoulder arthroplasty demonstrated that 90% of patients treated achieved satisfactory outcomes, though 30% experienced recurrent subluxation.4 Findings from posterior plication highlight the potential of soft tissue interventions, including posterior capsulorrhaphy, to address instability while preserving the range of motion. In our technique, suture anchors can be easily placed through a percutaneous portal and easily used to secure the posterior capsule directly to the glenoid rim to address posterior capsular laxity. This technique leverages a percutaneous posterior portal, knotless anchors, and tensioning under direct visualization through a standard deltopectoral approach. It can be performed with commonly available tools and may serve as a soft-tissue–based alternative to bony correction or reverse shoulder arthroplasty in select cases. In the correct patient, posterior capsulorrhaphy can be a valuable technique to achieve humeral head centering. Proper execution of this technique may result in a more stable anatomic shoulder reconstruction, contributing to improved long-term functional results and patient satisfaction. In revision or complex cases with significant bone loss or fixed deformity, reverse shoulder arthroplasty or augmented glenoid implantation remains the more reliable solution. However, in primary anatomic arthroplasty where instability is primarily soft-tissue–driven, the described percutaneous technique provides a less invasive and reproducible option for restoring humeral head centering. While our personal experience has demonstrated reliable humeral head recentering and stable motion with this technique, formal clinical outcome data is not yet available. One limitation of this report is the lack of clinical outcome data and future work is needed to evaluate the durability and long-term outcomes of this approach. Complications Posterior capsulorrhaphy during anatomic total shoulder arthroplasty and hemiarthroplasty is a careful balance between restoring centering of the humeral head over the glenoid, posterior stability, and preserving glenohumeral range of motion. Intraoperatively, it is essential to assess and adjusted to avoid excessive capsular tensioning that could impede joint motion. If humeral head centering is not achieved after capsulorrhaphy, additional measures such as using an anterior eccentric head using a high offset humeral head, rotator interval plication, or conversion to RSA may be considered.3,5 Adjustments to capsular tension should be performed with the guideline of the “40-50-60 rule” and the use of intraoperative fluoroscopy to confirm adequate humeral and glenoid component positioning and that the humeral head is centered throughout motion. Portal placement is also critical, as a suboptimal portal trajectory can force the drill guide and anchors into an acute angle, leading to slippage on the glenoid edge and compromise anchor fixation or capsular tensioning. The posterior working portal should be established within the well-described safe zone beneath the posterolateral acromion, taking care to maintain a trajectory that stays superior to the course of the axillary nerve and lateral to the suprascapular nerve.6 During switching-stick passage, direct visualization and tactile feedback should be used to confirm that the instrument remains above the expected course of the axillary nerve. If optimal alignment with the posterior glenoid rim is difficult to achieve, a curved or offset drill guide can improve anchor trajectory. Care should also be taken to avoid drilling into the glenoid component pegs, particularly in smaller glenoids or those with posterior bone loss. Lastly, posterior capsulorrhaphy may be less effective in cases of severe glenoid retroversion or extensive posterior bone loss requiring osseous correction, irreparable rotator cuff tears, and significant scarring or stiffness of the posterior capsule. In addition, correction of posterior instability with posterior capsulorrhaphy during revision anatomic total shoulder arthroplasty or conversion of failed fracture surgeries has been associated with high failure rates. In these cases, RSA may be a more reliable option.3,5