Placing Knotless Suture Anchor through Mid-Glenoid Portal

Abstract

Optimal portal placement for arthroscopic shoulder stabilization procedures can significantly aid a surgeon’s visualization during the repair as well as suture anchor placement. A percutaneous knotless anchor insertion kit used through a mid-glenoid portal allows the surgeon to access positions on the glenoid rim that are commonly difficult to reach. Moreover, the knotless kit has the ability to save valuable time during arthroscopic stabilization procedures and also eliminates the risk of postoperative knot impingement. The mid-glenoid portal should be made approximately 1 cm lateral from the joint line of the humeral head and 2 to 3 cm inferior and 1 to 2 cm medial from the posterolateral acromial angle. This portal placement avoids injury to the labrum and should be determined after assessing both the thickness of the local soft tissues and the size of the relevant bony architecture. A hole for the knotless anchor should be drilled approximately 1-2 mm onto the face of the glenoid, and the labral tape is then passed a short distance through the eyelet of the knotless fixation device before the construct is inserted into the glenoid. A hemostat is used to hold the tape as it is placed into the drill hole, and a mallet is used to drive the interference portion of the plastic implant to a marked depth. Finally, once the suture anchor is securely affixed, the insertion device is unloaded and pulled out of the portal with 6 counter-clockwise turns.

Case Overview

Background

Traumatic anterior shoulder instability often results in the compromise of both the anterior labrum and the anterior capsule, causing a traditional Bankart lesion. Bankart lesions have a prevalence of 97% in all first-time dislocators, which can predispose the patient to recurrent instability.¹ Other risk factors that predispose the patient to recurrent instability are young age at the time of the initial event (less than 20 years of age), participation in a competitive sport, playing a sport that is overhead or includes impact, preoperative shoulder laxity and signs on plain radiographs significant for instability (Hill-Sachs and loss of glenoid contour).² Multi-center trials have shown that patients who receive treatment earlier in their course of instability (i.e. the first-time dislocator) are more likely to undergo an arthroscopic Bankart repair and are less likely to have bone loss or other biceps pathology.³ With a thorough preoperative workup and careful patient selection, arthroscopic Bankart repairs have shown recurrence rates of 8% at 2-year follow up and 22% at mean follow-up of 6.3 years.^4-5

Focused History

A 16-year-old competitive male skier presented to the orthopedic clinic after having sustained a fall and dislocation of the right shoulder. The patient is otherwise healthy and has had no prior injuries to the shoulder nor has he had any dislocation of the left shoulder. The injury happened 1 week prior to presenting to clinic and the patient has been using a sling for comfort since that time. His chief complaint at this time is instability of the shoulder as well as a lack of confidence throughout range of motion.

Focused Physical Exam

The patient is a well-appearing male without signs of abrasions or ecchymosis to the shoulder. The patient is neurovascularly intact to include endorsing normal sensation to the axillary dermatome and full strength of the deltoid and rotator cuff muscles. He reports apprehension when his arm is abducted and externally rotated and has relief of symptoms when a posterior force is applied to the proximal humerus. He has grade I instability (humerus to the glenoid rim) with an anterior load and shift test. He has no pain with the Kim and jerk tests and does not have a sulcus.

Imaging

A standard shoulder series (AP/Grashey/Axillary/Scapular Y) is obtained and demonstrates a well-reduced glenohumeral joint without superior humeral migration and a normal acromiohumeral distance. There is no obvious Hill-Sachs nor is there loss of glenoid contour/signs of anterior bone loss. Furthermore, no bony-Bankart or signs of fracture can be identified. An MRI of the right shoulder without contrast demonstrates undermining of the anterior labrum without a periosteal avulsion or medialization of the labrum along the glenoid neck. The biceps is intact without signs of a SLAP lesion.

Natural History

Young male patients under the age of 20 have recurrent rates ranging from 66-100%.⁶ Recurrent shoulder instability not only predisposes to bone loss, but Hovelius et al. have shown higher rates of instability arthropathy at 25 years after dislocation (40% with recurrence versus 18% without recurrence).⁷

Treatment Options

Non-operative management with the use of a sling and shoulder rest has been discussed by various authors. Although clinical evidence is controversial, Itoi et al. have shown a decrease in relative risk of recurrence by 46% if the patient is immobilized in external rotation.⁸ Furthermore, long-term studies have shown that at 2, 5, 10 and 25 years, 50% of patients have recurrent instability events if treated non-operatively, with the majority recurring within the first 2 years after the seminal event.⁹

Treatment Rationale

A thorough discussion of risks, benefits and expected outcomes were discussed at length with the patient. An 18-year-old equivalent male through predictive modeling has been shown to have a 77% risk of recurrence at 1 year, which decreased to a 17% risk at 1 year with surgical stabilization.¹⁰ The patient and his family felt that the risk of recurrence was unacceptably high and they elected to proceed with arthroscopic Bankart repair after the first-time dislocation.

Discussion

Arthroscopic Bankart repair in the setting of traumatic anterior shoulder instability has been shown to decrease risk of recurrence.^3-5,10 Surgical techniques continue to advance in terms of utilization of accessory portals and technological advances with anchor types.

Wolf et al. described the first arthroscopic Bankart repair with the use of a posterior viewing portal and 2 anterior working portal Mitek anchors that required knot tying.¹¹ Techniques continue to utilize 2 anterior working portals in varied positions (i.e. high anterior rotator interval, mid-glenoid, and 5:30 trans-subscapularis portal) with good to excellent results and highly dependent on the operator.¹² Furthermore, recent techniques have described utilizing a single anterior portal with the benefit of reduced pain, shorter surgical time and shorter learning curve, all with the same results compared to historical controls.^13-15 Surgeons should be aware of possible shortcomings of portal placement and utilize new curved guides when appropriate to avoid posterior cortex perforation.¹⁶ The senior author advocates for the use of an accessory rotator interval portal as well as a mid-glenoid working portal.

Knotless anchors have been shown to have equivalent clinical outcomes when compared to the gold standard Bankart repair with traditional suture anchors that require knot tying.^17-19 Furthermore, knotless anchors have many purported benefits. A successful Bankart repair with knot tying solely relies upon knot security and maintained tissue tension, which can be operator-dependent and variable. As a result, knotless anchors offer a solution to avoid the weakness in traditional Bankart repair techniques.²⁰ Furthermore, a known complication of knot tying in a traditional Bankart repair is knot arthropathy, where the suture can actually abrade the cartilage surface of the glenoid and humeral head.^21-22 As a result, a knotless Bankart repair construct offers an alternative option for the surgeon to produce reliable results without the possible complications associated with knot tying.

Equipment

• 3.0 mm Arthrex Knotless SuturTac Anchors
• Standard orthopedic operative table
• Bean bag for lateral position
• Arthrex Shoulder Suspension System

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 T.J.D.) 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.