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Capsulolabral augmentation is one of the most used arthroscopic techniques to address multidirectional instability of the shoulder. Given the thin and weak capsule seen in the affected patients, reconstruction in this subset of patients can be particularly challenging. This arthroscopic technique aims to reduce the capsular volume and deepen the glenoid socket through the creation of a particularly voluminous “bumper” along the glenoid bone. Increasing the depth of the glenoid facilitates a concavity-compression stabilizing effect and, therefore, shoulder stability, especially midrange stability. This technique aims to augment the bump of the standard capsulolabral reconstruction by using a resorbable surgical mesh derived from porcine skin.
Technique Video
See video under supplementary data.
Multidirectional shoulder instability represents an ongoing challenge for orthopaedic surgeons.
Surgical treatment should be considered for patients showing debilitating or invalidating symptomatology despite proper rehabilitation.
Among the most common surgical procedures, capsuloligamentous techniques—which include open inferior capsular shift, arthroscopic plication, and thermal capsulorrhaphy—are the most frequently used
Yet, this approach can prove inadequate in case of poor-quality capsuloligamentous structures caused by constitutional hyperlaxity or due to one or more surgical procedures.
The surgical technique we recommend consists of a glenoid labrum reconstruction performed with a resorbable surgical mesh derived from porcine skin able to increase glenoid height and surface. This technique is an additional step in traditional capsuloplasty procedures and it is not an alternative to them. We think that increasing the glenoid depth could reduce the frequency and extent of tensile solicitation of the humeral head on the ligamentous structures.
This methodology is particularly recommended in cases in which traditional procedures are burdened with a substantial rate of recurrences:
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Atraumatic instability, even voluntary, in symptomatic patients
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Multidirectional recurrent atraumatic instability in patients with constitutional laxity
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Surgical revision, even following a Latarjet procedure, in patients with constitutional laxity, fragile capsule, and no bone deficiency
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When capsule weakness is an unexpected intraoperative evaluation finding
A dislocation caused by a low-energy trauma showing no bone deficiency points toward labrum augmentation using grafts.
Surgical Technique
Physical features of the glenoid bone have been reported as 39 ± 3 mm in the superior-inferior dimension, 29 ± 3 mm in the anteroposterior dimension of the lower half, and 23 ± 3 mm in the anteroposterior dimension of the upper half. The space available for graft placement is 45 ± 5 mm long. This value corresponds to the lower half of the circumference inscribed in the subequatorial portion of the glenoid, and it is calculated as follows: (diameter × pi)/2, so that (29 + 3 × pi)/2. The glenoid labrum increases joint depth by up to 50%.
Anatomical studies showed that glenoid cavity depth measures 9 mm in the superior-inferior direction, and 5 mm in the anteroposterior dimension. A greater depth of the glenoid cavity provides better stability to the shoulder. Therefore, the graft should be more than 45 mm long (perimeter of the inferior glenoid bone) and 2.5 mm thick (regular glenoid labrum).
Arthroscopic Technique
Video 1 is a case description of our technique in a left shoulder. The patient is placed in a lateral decubitus position and 3 to 4 kg traction is applied with the upper limb at 50° of abduction and 20° of anterior flexion. We open 3 to 4 arthroscopic portals: 3 standard (posterior, anterosuperior, midglenoid), held by a cannula (Fig 1); the accessory (posterolateral) (Fig 2) one can be useful to insert the most distal anchor at the 6 o'clock position. For the midglenoid portal, we recommend the use of a cannula with the removable cannula cap (Clera-Trac, Smith & Nephew, Hull, UK), which facilitates graft insertion. For the other portals, we use standard cannulas (Threaded Clear Cannula with Obturator 8.5 mm × 75 mm, DePuy Mitek, Raynham, MA).
Fig 1Patient in lateral decubitus, left shoulder. The 3 portals held by a cannula are visible: posterior, anterosuperior, and midglenoid. The anterosuperior portal is mainly used for intra-articular viewing during the procedure.
Fig 2Patient in lateral decubitus, left shoulder, posterior viewing of the left shoulder. A posterolateral portal (dermographic pen) can be used for a better anchor placement in the inferior portion of the glenoid bone (6 o'clock). A red arrow marks the standard posterior portal.
The glenoid labrum (thin, when present) and the capsule are detached from the 3 to 9 o'clock position (Fig 3), the scapular neck is decorticated, and then the capsulolabral reconstruction is performed according to the surgeon's preferred method (Figs 4 and 5).
Fig 3Patient in lateral decubitus, left shoulder, camera in the anterosuperior portal. Capsuloligamentous structures already detached from the subequatorial portion of the glenoid bone. The tool lifts the disconnected medial margin of the capsule and shows the decorticated glenoid neck.
Fig 4Patient in lateral decubitus, left shoulder, camera in the anterosuperior portal. Capsulolabroplasty is performed using double-loaded all-suture anchors. Anchor threads at the 6 o'clock position already passed through the capsular tissue; using a shuttle technique, we are working in the posteroinferior quadrant, with the second anchor seated at the 4.30 position. In this phase, a South-North shift of the capsular tissue needs to be obtained; therefore, the tool must emerge distally from the anchor.
Fig 5Patient in lateral decubitus, left shoulder, camera in the anterosuperior portal. The capsulolabroplasty is finished, the capsuloligamentous structures are retensioned, and a new glenoid labrum (called “bumper”) is reconstructed.
The graft length needed can vary; 5 cm is sufficient for all cases in which the prevalent direction of the instability is the inferior one. The maximum available graft length is 10 cm. We use a 5- to 10-mm-thick graft—at least twice the size of the regular glenoid labrum—that is added to the new labrum obtained by capsular plication. The excess membrane is cut out. The membrane (DX Reinforcement Matrix, Arthrex, Naples, FL) is folded, and then sutured by the “SpeedWhip” technique. We use a resorbable suture Vicryl No. 1 (Ethicon, Somerville, NJ) that makes the membrane stiff and keep its shape until it is inserted into the joint. The 2 free limbs of the suture are tied to form a loop that is armed on an eyed needle. Straight 18-gauge needles (Fig 6) ease the needle suture passage through the folded membrane, which is particularly rigid: they pass through the membrane, carrying on their tips that transport the suture; by retreating, these straight needles allow a smooth needle and thread passage through the membrane (Fig 7).
Fig 6The membrane is folded to assume a cylindrical shape. Two surgical clamps fix the membrane at the extremities. To keep the shape during suturing and ease the needle passage, straight 18-gauge needles pass through the folded graft. All needles have to be inserted in the same direction.
Fig 7The Vicryl No.1 (Ethicon, Somerville, NJ), tied to form a loop, is inserted in an eyed needle. Passing through the straight needles, the eyed needle pierces the graft and the suture thread along with it. The same procedure is to be performed with further needles, managing the suture with a SpeedWhip technique.
Both limbs of 3 more sutures, LabralTapes (Arthrex), are passed through the graft: in its middle, anterior, and posterior part. Each LabralTape passes through the graft to shape a “U” with its free limbs coming out of the same side of the graft itself. These 3 LabralTapes are then used to secure the graft to the glenoid bone. The temporary tying of the limbs of each suture and the use of different color sutures can ease suture management (Fig 8). In this case we color the central FiberTabe blue.
Fig 8A resorbable thread keeps the cylindrical shape of the graft. Three LabralTapes (Arhtrex, Naples, FL) pass through the graft at both ends and in the center. The free limbs of each LabralTape come out of the same side of the graft to shape a “U.” The central LabralTape has a different color to ease suture management within the articulation. We recommend tying together the loose ends of each LabralTape. The 2 LabralTapes at the extremities are used to anchor the graft to the anterior and to the posterior margins of the glenoid. The central LabralTape is used to anchor the graft at the 6 o'clock position. The posterior LabralTape is used to pull the graft inside the joint.
After the removal of the cannula cap from the midglenoid portal, the LabralTape of one end of the graft is inserted into the joint through the midglenoid portal, and pulled out from the posterior portal (Fig 9) until the graft enters into the joint. At this point, the 2 limbs of the posterior LabralTape come out from the posterior portal, whereas the limbs of the other 2 LabralTapes (the middle and the anterior ones) are still located in the midglenoid portal; the graft is in place into the joint.
Fig 9One of the LabralTapes at the extremity of the graft is inserted into the articulation through the midglenoid portal and retrieved from the posterior one. Applying traction to this LabralTape, the graft is pulled into the joint through the midglenoid portal.
The graft fixation point to the glenoid starts as inferior as possible: the central LabralTape of the graft (Fig 10) is secured at the 6 o'clock position by a knotless suture-anchor (PEEK PushLock 2.9 mm × 15.5 mm, Arthrex); it comes through the posterolateral portal or the midglenoid one. Two further knotless suture anchors complete the fixation: one anteriorly and one posteriorly (Fig 11). Variable amount of additional single-suture implants stabilize the graft that is finally placed around the whole perimeter of the subequatorial portion of the glenoid (Fig 12). The fixation could be extended proximally to the anterior, posterior, or both sides, depending on the prevalent instability direction.
Fig 10Patient in lateral decubitus, left shoulder, camera in the anteroposterior portal. Once a hole has been made at the 6 o'clock position, the central LabralTape (the one differently colored) is anchored to the glenoid with a knotless anchor through the midglenoid portal.
Fig 11Patient in lateral decubitus, left shoulder, camera in the anteroposterior portal. The graft is anchored to the posterior margin of the glenoid with a knotless anchor (red arrow) through the posterior portal.
Fig 12Patient in lateral decubitus, left shoulder, camera in the anteroposterior portal. The graft made of resorbable surgical mesh derived from porcine skin is anchored to the glenoid rim along the entire subequatorial region.
A shoulder sling should keep the affected shoulder immobilized for 6 weeks, followed by nightly use of the sling for the subsequent month.
Scapulothoracic proprioceptive recovery starts before the surgical procedure, and immediately resumes during the first postoperative period.
Once the support is removed, glenohumeral joint range of motion recovery can start: initially only through active exercise to avoid stressing the capsule. To avoid muscle atrophy, a mild isometric strengthening exercise can be started when the sling is removed. After 2 to 3 months, a rotator cuff and scapular stabilizer isotonic reinforcing program can begin to improve dynamic stability and neuromuscular control. Sport-related training should not begin before 6 to 9 months after surgery, and full articular recovery (especially in abduction and extra rotation) should not be made before 1 year after the procedure.
Discussion
The labrum not only provides an attachment area for the glenohumeral ligaments, but it also increases the joint surface area and deepens the glenoid cavity; it generates negative intra-articular pressure and produces a “wedge-like blocking effect.”
Active coaptation of the humeral head against the glenoid bone seems to be a more relevant element of stability than negative intra-articular pressure or ligament tension.
An increase of the concave joint depth—and therefore of the “stability ratio”—helps active compression forces in maintaining joint stability. Active stabilization is important when ligaments, which stretch only at maximum grades of articolarity, are not tensioned. If active stabilization is insufficient, it determines midrange instability.
proved that the resection of the glenoid labrum in 10 anatomical specimens resulted in a stability decrease in all directions, calculating that the labrum contributes to shoulder stability by approximately 20%; the highest value (37%) was detected in the posteroinferior direction compared with others (18%). A following study
downsized the average contribution of the labrum to shoulder stability to 10%. In the inferior region of the glenoid bone, contrary to the superior one, the labrum still plays a relevant role, and its resection produces an increase of humeral head translation. Older studies probably overestimate glenoid labrum contribution, because their authors, while producing the experimental lesion, also damaged the capsule and the glenohumeral ligament insertion. Pouliart and Gagey,
who conducted a study on the sequential arthroscopic resection of the glenoid labrum without damaging the capsuloligamentous structures, determined an inferior labrum contribution to shoulder stability compared with the results of previous studies; the resection of the anterior labrum increases humeral translation in 50% of the specimens, whereas the resection of the inferior labrum increases inferior translation in just 20% of samples.
Cadaveric experiments are often conducted using specimens derived by elderly individuals, whose glenoid labrum suffered age-related deterioration. A reduction of the glenoid-labrum contact surface due to aging—as long as the glenoid surface remains unchanged—is caused by the deteriorating of the glenoid labrum, that becomes thinner.
These studies likely underestimated the effective role played by the glenoid labrum.
In any case, although capsuloligamentous structures have a major role in ensuring shoulder stability in healthy subjects if compared with the glenoid labrum, when these structures are of poor quality and their biomechanical functioning is not optimal, glenoid labrum contribution to shoulder stability becomes crucial. In patients with these features, it is important to combine capsuloligamentous reconstruction with labrum augmentation, as a means to provide additional stabilization, taking advantage from the “wedge-like blocking effect” and increasing the glenoid cavity depth.
Capsuloplasty surgical techniques, open or arthroscopic, are used to treat multidirectional instabilities, but they might not be conclusive when the capsular tissue is weak or excessively elastic.
Recurrence rate in these patients is similar (7.5% to 10%) both after arthroscopic capsulolabral reconstruction and open capsular shift,
because these procedures operate through the same biomechanical principle by retensioning capsuloligamentous structures. Moreover, elastic tissues are at risk to fray due to continuous solicitations by the humeral head, thus explaining results deterioration in time.
With such thin tissues, the new labrum, obtained through capsular plication, is too soft and cannot apply an efficient mechanical effect. In a cadaver study, Yamamoto
proved how a new labrum just reconstructed (thus made up of fresh and compressible tissue) does not increase shoulder instability. This technique adds the stabilizing effect of a stiff and high bumper to the biomechanical benefits of standard capsuloplasty techniques.
Published techniques foreseeing the use of a graft for anatomical structure augmentation aim to reconstruct the anterior shoulder capsule,
and eventually the anterior glenoid labrum only. No technique currently takes into consideration the importance of performing a complete subequatorial, anterior, inferior, and posterior augmentation of the glenoid labrum to reduce tension on the capsuloligamentous repair and improve active centering of the humeral head (concavity compression). We believe, in fact, that the augmentation of a barrier (new labrum) at the periphery of the glenoid rim can reduce the frequency and intensity of humeral head solicitation on the ligaments, protecting them from further plastic deformation. The graft acts as a barrier by reducing the energy of the humerus translation. This technique can increase the “wedge-like blocking effect” of the newly reconstructed bump, thus reducing the humeral head slipping toward to the bottom during abduction by hastening its rotation.
We suggest labrum augmentation also for patients with laxity showing postsurgical recurrences with no bone defect.
Glenoid labrum augmentation is added to capsulolabral plasty, and it thus increases either operating time or costs (devices and membrane). This is a reproducible and standardizable technique involving portals and setups commonly used during shoulder arthroscopy, without requiring specific surgical tools. Finally, the used membrane can be stored in package and be available, when needed, in the operating room (Tables 1 and 2).
Table 1Pearls and Pitfalls of Arthroscopic Labral Augmentation
Pearls:
1. Use a LabralTape that has a different color at the center of the graft
2. Tie together the free limbs of each LabralTape to ease suture management
3. For the midglenoid portal, use a cannula through which the graft can pass
4. Once inside the articulation, push the graft into the axillary pouch to increase the maneuvering area in inserting the anchor at the 6 o'clock position
Pitfall:
1. If the graft rotates around its own axis when pulled into the articulation, suture management can be difficult
Arthroscopic capsuloplasty with labrum augmentation can be a very useful and reproducible technique in patients with constitutional laxity or weak capsuloligamentous tissue; it should be considered in cases of multidirectional instability without relevant bone defect.
Left shoulder. The patient is placed in a lateral decubitus position; 3 arthroscopic portals held by a cannula are in place: posterior, anterosuperior, and midglenoid. Proper visualization is obtained through the anterosuperior portal, using a 45° arthroscope. A motorized tool is used to debride the damaged glenoid labrum. With radio frequencies and/or a shaver, the capsule is detached from the glenoid neck in the subequatorial portion, and the bone surface is decorticated. The spinal needle guides the opening and inclination of the posterolateral portal, through which a double-loaded anchor (Suturefix Ultra 1, Smith & Nephew) is inserted at the 6 o'clock position. Other anchors are subsequently inserted, through the anterior and/or the posterior portal, to perform capsulolabroplasty. In this case, because the prevalent direction of the instability is the posteroinferior one, 2 further anchors are inserted in the corresponding quadrant. Using a shuttle technique, nonresorbable sutures are passed through the capsuloligamentous complex; by tying the knots, a South/North shift is obtained. In those patients with hyperlaxity, the reconstructed labrum is not sufficiently rigid. Our goal is to obtain a thick and rigid bumper that would deepen the glenoid cavity and facilitate concavity compression. We use an acellular matrix membrane derived from porcine skin (in this case DX Matrix, Arthex) by cutting it to the required length (at least 5 cm) and folding it in a cigarette shape. Because the rigid membrane is difficult to be passed through with regular curved needles, we rely on straight 18-gauge needles. The 2 loose ends of a 90-cm-long resorbable suture (Vycril No. 1) are tied to form a loop used to prepare the graft with a SpeedWhip technique. The graft we obtain is 5 cm long, at least, and 1 cm thick. Three nonresorbable sutures or LabralTapes (Arthex) have to be placed on the graft—in the center and on the 2 loose ends—to secure it to the glenoid bone with knotless anchors. The loose ends of each suture have to pass through the graft in the same direction to shape a “U.” The LabralTape on one end of the graft is introduced through the midglenoid portal, and then is moved to the posterior one and pulled to drag the graft inside the joint. The new labrum is secured to the glenoid cavity with knotless anchors, starting from a 6 o'clock position and using the midglenoid portal; it is then secured with LabralTape at the posterior and anterior ends through the posterior and the midglenoid portals. Securing is completed, if necessary, with a shuttle technique and nonresorbable sutures by anchoring the graft to the capsule. The new glenoid labrum thus obtained is stable and it is able to increase the depth of the glenoid cavity.
References
Gaskill T.R.
Taylor D.C.
Millet P.J.
Management of multidirectional instability of the shoulder.
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