Modified Dynamic Anterior Stabilization (DAS) and Hill-Sachs Remplissage for the Treatment of Recurrent Anterior Shoulder Dislocation.

The optimal treatment for recurrent glenohumeral instability is a subject under debate. The recently described arthroscopic technique for dynamic anterior stabilization (DAS) fills the treatment indication gap between reconstructive bony procedures and soft tissue stabilization. However, indications for DAS are considered limited or not appropriate for patients with recurrent shoulder dislocations caused by severe bone defects. In this Technical Note, we present a modified all-arthroscopic DAS technique with added infraspinatus and posterior capsule remplissage to correct the extra-articular Hill-Sachs defect in a patient with recurrent dislocations and off-track bony lesions. The patient requested an alternative treatment option, other than the complication-prone Latarjet procedure.

Introduction

The management of recurrent anterior glenohumeral instability is still a matter of scientific debate.1, 2, 3, 4 The recently described dynamic anterior stabilization (DAS) is a promising technique. A report of three cases, supported by a biomechanical study and three Technical Notes,,, have demonstrated the efficacy of transferring the long head of the biceps through a subscapularis split onto the anterior glenoid rim. The obtained anterior sling effect dynamically stabilizes the shoulder joint while preventing anterior dislocation. Indications for DAS were clearly stated, although previous authors advised not to use this technique in shoulders with severe bone defects.,, However, the consequences and complications after glenoid augmentation procedures are concerning patients and surgeons.10, 11, 12 Therefore, we present the following alternative technique: modified all-arthroscopic dnamic anterior stabilization combined with Hill-Sachs remplissage (Video 1).

Surgical Technique (With Video Illustration)

Patient Installation and Arthroscopic Portals

The patient is installed in the beach chair position under total anesthesia with interscalene block. After surgical draping, a traction cable holding the forearm keeps the shoulder 30° of anterior elevation, 10° of abduction, and in a neutral rotation. Classic arthroscopic portals are used:

A portal, known as the soft spot, 2 cm medial and 2 cm inferior from the posterolateral corner of the acromion,

B portal at 2 cm inferior and lateral to the posterolateral corner of the acromion,

D portal at 2 cm underneath the anterolateral corner of the acromion right above the long head of the biceps tendon (LHBT),

E portal in front of the rotator interval so that any instrument enters tangent to the subscapularis upper margin.

First Step: Diagnostic Arthroscopy and Preparation

A 4-mm arthroscope is placed in the A portal, and a standard arthroscopic round diagnostic of the shoulder is performed. The engaging bipolar bony lesion is documented: a deep and wide Hill-Sachs lesion that dislocates over the anterior margin of the glenoid in passive external rotation at more than 30° of abduction, a sclerotic anterior glenoid rim, as well as the absence of the anterior labral tissue. An arthroscopic rasp is placed through the D portal, and the anterior margin of the glenoid is released of scar tissue, and the bone is decorticated, from 4 to 5 o’clock position. The presubscapular bursa and the lateral part of the clavipectoral fascia are removed with the shaver through the E and D portals, until the anterior surface of the subscapularis is well observed.

Second Step: Suture Management

A free FiberWire suture (Arthrex, Naples, FL) is introduced through the E portal and placed underneath the LHBT. Through the D portal, a perforating suture grasper, e.g., a Clever Hook (DePuy Synthes, Raynham, MA), is passed into the LHBT, grabs the free suture in the middle, and retrieves only 1.5 cm of it, creating a simple loop above the tendon. Through the same D portal, a suture grasper is forwarded into the loop and pushed posterior to the LHBT to grab one free limb of the suture, which is then retrieved, through the loop, outside the shoulder. The same step is performed, but this time the instrument grabs the remaining suture limb anterior to the LHBT through the loop. A 360° double lasso, similar to a pretzel form, is performed into and around the biceps (Fig 1). Both suture ends are then pulled outside the shoulder through the E portal, while the “pretzel loop” is tightened.

Fig 1

Initial suture management for the “pretzel loop”. Right shoulder arthroscopic view with the camera in the posterior portal: (A) A free suture is introduced above the subscapularis tendon (SSCAP) and humeral head (HH) right underneath the long head of the biceps tendon (LHBT). (B) The suture is passed through the LHBT using a piercing instrument, creating a simple loop above the tendon. (C) One suture end is passed posterior to the tendon and then retrieved through the loop then outside the shoulder. (D and E) The remaining suture limb is passed anterior to the LHBT and retrieved through the loop. (F) View from underneath the LHBT. (G) View from above the LHBT.

Third Step: Releasing the LHBT From the Intertubercular Groove and Proximal Tenotomy

The LHBT is released from its intertubercular tunnel by cutting the posterior pulley and the transverse ligament with the radiofrequency ablation probe (ArthroCare Corporation, Austin, TX) facing the lateral crista humeri through the D portal.

Fourth Step: Subscapularis Split

The arthroscope is placed into the D portal, and a Wirsinger rod (switching stick) is inserted into the A portal. The rod is advanced from posterior to anterior, parallel to the glenoid surface, until it pierces the subscapularis tendon, until its tip is visualized posterior to the conjoint tendon. The height of the subscapularis split is at one-third inferiorly and two-thirds superiorly, considering the height of the tendon. While performing gentle internal-external rotation, the subscapularis split is enlarged and prepared to receive the transtendinous transfer of the LHBT.

Fifth Step: Transferring the LHBT and Tenodesis

The switching stick is replaced by a suture grasper that pulls the LHBT sutures through the subscapularis split and then outside the A portal. Once the sutures are positioned for the coming transfer (Fig 2), a simple tenotomy is performed at the level of the LHBT root without injuring the superior labrum. The transsubscapular transfer of the LHBT is performed by gentle pulling of both suture limbs from the A portal, while simultaneously pushing the tendon with a tissue grasper from the E portal. Once the biceps is observed intraarticularly, its suture limbs are passed over the superior subscapularis margin and then retrieved outside the E portal.

Fig 2

Suture management preceding the trans-subscapular transfer of the long head of the biceps tendon (LHBT). Arthroscopic view from the anterolateral portal in a right shoulder with ➡ demonstrating the direction of the transfer. (A) “Pretzel loop” seen above LHBT and suture limbs descending extraarticulary towards anterior surface of the subscapularis (SSCAP). (B) view of the glenoid (G), the SSCAP, and the sutures passing through a SSCAP split. (C) Suture ends reentering the glenohumeral joint through the SSCAP split and retrieved outside the posterior portal. HH, humeral head.

The LHBT tenodesis is performed using a knotless 3.5-mm Pushlock anchor (Arthrex, Naples, FL) onto the anterior glenoid margin between 4 and 5 o’clock position, using the E portal. The sling effect is observed in the presubscapular space and intra-articularly (“outside and inside the box”) having the scope in the D portal. The suture ends are cut flush to the bone surface.

Sixth Step: Hill-Sachs Remplissage (Capsulotenodesis)

The surface of the Hill-Sachs defect is debrided with a burr through the A portal, while holding the shoulder in slight external rotation and increased anterior elevation. The arthroscope is brought back into the A portal, now pointed toward the Hill-Sachs defect. Keeping the shoulder in a neutral rotation, a 4.5 Helicoil anchor (Smith & Nephew, Andover, MA) is placed in a transtendinous fashion right into the Hill-Sachs defect. Anchor suture limbs are picked one by one using a Clever Hook and passed through the infraspinatus tendon and capsule in a mattress suture construct. Finally, the scope is pushed subacromially, all 4 suture limbs are retrieved together through the same B portal and then knotted down and cut.

Seventh Step: Final Arthroscopic Evaluation

The LHBT transfer is visualized through the D portal, while bringing the scope in the front and on the back of the subscapularis, “outside and inside the box”. Pointing the scope downward visualizes the correct release from the intertubercular groove with no kinking of the LHBT at that level. The effectiveness of the remplissage is observed when pointing the scope posteriorly and pushing the humeral head anteriorly like in an anterior drawer movement. Finally, gentle glenohumeral external-internal rotation is performed to observe the anterior sling effect and the coverage of the Hill-Sachs defect.

Postoperative Care

We recommend shoulder immobilization in a sling with abduction pillow and neutral rotation for the first 4 weeks, and then gradually passive mobilization and active assisted range-of-motion exercises. Active shoulder rehabilitation and physiotherapy can be initiated at 6 weeks but with active resistant elbow flexion limited to a maximum of 3 kg for another 2 months. Additional tips and tricks to this surgical technique (Video 1) are listed in Table 1.

Table 1

Tips and Tricks

- No cannulas are needed: Debride each portal on its undersurface to avoid bursal tissue or fascia interposition. - Clean thoroughly the presubscapular bursa until a complete view of the posterior surface of the conjoint tendon is seen, and you have a good view over the transverse ligament. - Through the E portal, bring the FiberWire suture underneath the long head of the biceps tendon (LHBT), exactly where the Clever Hook will exit after piercing the tendon; it facilitates catching the suture. - Perform the LHBT release from its groove always with the probe facing laterally, so as not to injure the subscapularis insertion. - Double check the complete release of the LHBT from its groove by changing the scope position into the D portal and pointing it inferiorly. Dissect and release further inferiorly if needed. - Make sure to have a good view of the subscapularis, on its posterior and anterior surface (“inside and outside the box”), so that you can observe the correct position of the split and to avoid advancing the Wirsinger rod way too anteriorly, through the conjoint tendon, for example. - Depending on the patient’s anatomy, it might be necessary to locate and dissect the axillary nerve in order to protect it, while performing the subscapularis split. - Rather, push the LHBT into the split through the E portal rather than pulling it by the sutures from the A portal, or at least perform both simultaneously - Perform site preparation and suture management first, and LHBT tenotomy and tenodesis at the end.

Institutional Review Board Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study, formal consent is not required. The patient signed a specific consent accepting that anonymized medical data, including video recording of the surgery, can be used for scientific and educational purposes as long the patient identity and personal data are protected.

Discussion

When confronted with recurrent anterior shoulder instability, treatment options depend on the defect size of the glenoid and of the humeral head.,, So far, soft tissue stabilization procedures (labral reinsertion, remplissage techniques) and bone augmentation techniques (Latarjet, Eden-Hybinette) have been shown to be effective if their indication respects the demonstrated threshold related to off-track/on-track measurements of the bipolar lesion.,,, However, each technique has specific limitations. Shoulder instability is a dynamic condition, and as previous research demonstrates, the recommendation to opt out of soft tissue stabilization in favor of bone augmentation, or vice versa, is constantly changing.,

The newly introduced DAS technique can fill the treatment indication gap, at least in selected cases, as in the case presented here, however, not alone, because of the large engaging Hill-Sachs defect.,

Latarjet and Eden-Hybinette procedures are technically demanding, with a long learning curve, and have associated risks of neurovascular injuries, among other significant complications. Graft complications are well known, similar to the postinterventional risk of developing arthrosis due to the increased pressure created by the graft on the humeral cartilage., The Latarjet procedure contains an additional risk of consequent superior instability by damaging the coracoacromial ligament and may create scapular dyskinesis because of the mandatory pectoralis minor tenotomy. Furthermore, it may be insufficient in persistent off-track cases caused by big Hill-Sachs defects, in which case a combined procedure should be performed.

The DAS technique creates the desired stabilizing anterior “sling and hammock effect,” and the remplissage renders the Hill-Sachs defect extra-articular. The combination of the two treatment options is an alternative to the more complicated trans-subscapular transfer of the coracoid process but without the neurovascular or graft risk. Moreover, it can be performed with minimal invasion, without the need of complex dissection or graft preparation, using only 4 standard arthroscopic portals.

Advantages and limitations of the presented combined technique of arthroscopic DAS and remplissage are listed in Table 2. Surgical risks are considered to be lower than in the arthroscopic Latarjet technique, but they are all related to the quality of the arthroscopic dissection and proper visualization:

Table 2

Advantages and Limitations

Advantages	Limitations
Simple and straightforward technique, safer than the arthroscopic Latarjet	No long-term follow-up
All arthroscopic procedure with excellent visualization and control	Revision options and complications management are still under research.
Implies standard arthroscopic equipment, instruments, and implants	Routine experience in shoulder arthroscopy is required.
The “pretzel loop” is a simple 360° suture fixation construct that does not slide even when longitudinal raisers of the tendon occur, and it contains less suture material than the Krakow stitches	The concomitant remplissage can limit the external rotation.
General advantages of the dynamic anterior stabilization (DAS) technique5 strengthened by the added Hill-Sachs remplissage:- hammock effect in lower abduction, sling effect in high abduction and external rotation	General disadvantages of the DAS technique:5- weaker sling and hammock effect than after the Latarjet procedure - no glenoid surface augmentation- can modify arm shape and create biceps pain

risk of damaging the axillary vessels and nerve or the nerve branches for subscapularis muscle,

risk of insufficient liberation of the LHBT from its groove, causing recalcitrant postoperative pain or range of motion limitation,

risk of longitudinal tearing the LHBT during the suture management, and

risk of improper tenodesis on the antero-inferior glenoid border if the tension in the transferred LHBT is too high.

One of the drawbacks of this procedure is that there are no known long-term follow-up results. Until these become available, it is recommended that the surgeon have revision options in mind, which will certainly inform future biomechanical studies in the evolving field of shoulder instability.