1 Introduction

After primary traumatic shoulder dislocation and conservative treatment, the risk of redislocation is very high in patients younger than 35 years. With age the risk of redislocation after traumatic shoulder dislocation and conservative treatment decreases. Surgical treatment via either open or arthroscopic stabilization minimizes the risk of redislocation.^1–4

Today, anterior shoulder stabilization by arthroscopic refixation of the labroligamentous complex with suture anchors is becoming the standard therapeutic procedure, if there is no severe chronic bony defect at the glenoid site.¹,⁵ Lafosse et al. described the so-called „Lasso-loop stitch“.^6–9 This technique allows positioning of the knot away from the joint and at the same time it establishes the sought labral bump.

With the “Oblique mattress lasso-loop stitch” Parnes et al. published a resembling arthroscopic technique, but without giving clinical results.¹⁰

The surgical principle and aim consist of refixation of the anterior labrum-capsule-ligament complex to the glenoid with positioning of the knot at distance to the joint as well as bulging up the labrum. This is supposed to lead to stabilization of the shoulder joint and should avoid further dislocation and associated pathologies.

Using lasso-loop stitches probably leads to more bulging up of the labrum than with other stitching techniques as for example single interrupted stitch or mattress stitch. The lasso-loop stitch can enhance the physiological bumper effect of the glenoid labrum and can therefore avoid redislocation.

Indications for this operation are shoulder instabilities with reconstructable damage to the labrum: Bankart lesion, bony Bankart lesion, ALPSA, Perthes lesion, and reversed (posterior) Bankart lesions as well as injuries to the long head biceps tendon anchor (SLAP).

Contraindications are arbitrary shoulder dislocations during growth period without damage to the labrum and chronic bony glenoid defects >20% of the joint surface.^11–13 HAGL lesions acquire a humeral refixation.¹⁴

Patient consent should contain the following issues apart from the standard operation risks: cartilage damage, lesion to the axillary nerve, suture rupture, switching to open surgical procedure in case of larger bony defects, standardized postoperative treatment, restriction of motion (especially external rotation), redislocation, anchor dislocation, osteolysis in case of resorbable anchors, posttraumatic arthritis, pain, hospitalization for 1–2 days, day surgery possible, work leave dependent on job and arm dominance 2 days to 16 weeks.

While recording the patient history it is critical to differentiate between traumatic and habitual cause and evaluate the main symptom, either pain or instability. It is followed by a standardized clinical examination including apprehension sign and determination of the instability direction as well as evaluating an existing hyperlaxity. X-rays of the shoulder in three planes (true a.p., y-view, axial) and MRI (Fig. 1) are performed.¹⁵,¹⁶ The surgical site should be shaved if strongly covered by hair. An examination under anaesthesia is performed to record the passive glenohumeral range of motion following the neutral-zero method as well as evaluation of glenohumeral stability and translation according to the modified Hawkins classification⁶ and exclusion of multidirectional instability. In case of larger glenoid defects, a CT scan is necessary.¹⁷

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Fig. 1 MRI of the right shoulder of a 21-year-old male after primary traumatic anterior-inferior shoulder dislocation. The transverse image shows a classic Bankart lesion (arrow).

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The aim of this work is to give an illustrated instruction of the operative technique of arthroscopic Bankart repair using the lasso-loop stitch and to analyze the clinical outcome of this surgical procedure.

Based on our experience with this technical modification to the classic arthroscopic Bankart repair, we hypothesize very good clinical results and high patient satisfaction.

2 Materials and methods

We identified all 30 consecutive patients (3 females, 27 males), who had been treated for shoulder dislocation with anterior-inferior damage to the glenoid labrum by arthroscopic refixation of the anterior capsulolabral complex with suture anchors in lasso-loop technique in one single orthopaedic center between January and December 2014.

Five patients were either not available or not prepared to take part in the follow up. 25 of 30 patients could be followed up. One patient had to be excluded for a recent ipsilateral elbow fracture dislocation. In this case, no shoulder redislocation occurred.

We operated all patients under full anaesthesia (ENT). Preoperatively a prophylactic antibiotic single-shot dose of 2g Ampicillin and 1g Sulbactam i.v. were given. Dependent on preference the operation can be done in beach-chair-position or lateral decubitus position with lateral tension, which increases the intraarticular space by putting traction on the arm. Alternatively, a special arm holder with free positioning of the arm in slight abduction and external rotation can be used. We routinely used the latter option in all cases.

After diagnostic arthroscopy fixation of the anterior capsulolabral complex with suture anchors in lasso-loop technique was done. Table 1 shows the used instruments.

2.1

2.1 Surgical technique

Figs. 2–4 illustrate the surgical technique.

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Fig. 2 The lasso-loop stitch (a–d). The Birdpeak is pushed through the capsulolabral complex from anterior (a). Then one suture end of the anchor is grasped (b), pullled through the capsulolabral complex anteriorly and formed into an intraarticular loop (c). The Birdpeak is pushed through the loop and the same suture end is grasped again (d). Now the Birdpeak is kept closed and the suture end is pulled out of the shoulder joint through the working cannula. During this procedure, the other suture end outside of the shoulder joint is secured by a clamp.

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Fig. 3 Tying of the knot (a) and shortening of both FibreWire ends with arthroscopic scissors (b).

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Fig. 4 Right shoulder at the end of surgery.

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Incision for posterior arthroscopy portal 2 cm caudal and 2 cm medial of the posterolateral corner of the acromion. Entering the glenohumeral joint with a changing rod, then the arthroscopy sheath, filling the joint up with water and insertion of the arthroscope.

Diagnostic round and incision for the anterior inferior working portal in outside-in technique just above the subscapular tendon and insertion of a working cannula (8.25 mm).

Examination with a hook probe, mobilisation of the labrum with the Bankart raspatory and debridement of the glenoid neck with the Bankart rasp.

Incision for an anterior superior portal and insertion of a working cannula (5.5 mm).

Trial cranialisation of the capsulolabral complex is performed via a grasper through the anterior superior portal followed by insertion of a hold-suture (PDS no. 0).

Positioning of the first single armed resorbable suture anchor through the anterior inferior portal onto the anterior glenoid rim as caudal as possible at the anterior cartilage border. Insertion of the anchor at about 135° to the glenoid plane. Not too steep and not too flat. The anchor should not be inserted too deep either; under no circumstances should the end of the anchor stick out, as this can lead to cartilage damage and cause anchor dislocation.

Cranialisation of the labrum via the hold-suture and refixation of the capsulolabral complex in lasso-loop technique. Also, the second suture end is stitched through and behind the labrum, so the knot comes to lie away from the joint. This suture end represents the drawstring. Seven singular knots are made.

Then the clamp is switched and with the birdpeak the second suture end is pulled anteriorly through the labrum and outside of the joint through the anteroinferior working cannula.

Now the hold-suture can be removed as it is no longer needed after tying of the first anteroinferior suture anchor.

Slightly further cranial labral refixation is undertaken in the same way with the second anchor. A further hold-suture is not needed after the first anchor is sutured.

In most cases an additional third anchor is necessary further cranial for secure labral refixation using the same technique. Enough distance has to be kept from the long head biceps tendon origin not to compromise this tendon mobility.

Final examination of labrum stability with a hook probe and careful clinical verification of joint stability.

Removal of instruments, skin disinfection, closure of the arthroscopic portals via interrupted single Donati backstitches, and sterile wound dressing as well as immobilization with Gilchrist bandage.

2.1.1

2.1.1 Tips and tricks

Only if the second suture end is also positioned behind the labrum, the knot will come to lie away from the joint surface.

Pulling on the one suture end without the loop reattaches the capsulolabral ligament complex to the glenoid. Strain to the other suture end – the one creating the loop – would pull the tissue away from the glenoid. Therefore, the singular stitched suture end has to be the drawstring while tying the knot.

When using the lasso-loop technique only one of the anchor dependent suture ends can slide through the tissue. Therefore, no arthroscopic slip knots can be made. Seven half hitches come into use. Alternating half hitches lead to a secure blocking of the knot.

3 Results

In total, we followed up three female and 21 male patients completely. The mean age was 27.8 years (17–49 years). The average follow up took place 30.4 months (25–36 months) postoperatively.

In 96% of all cases there was an excellent subjective and objective outcome. The average Rowe Score was 96.3 points (80–100 points; SD = 3.9). The mean QuickDash was 2.8 points (0–14 points; SD = 3.9). The Constant Score had an average of 93.7 points (65–100 points; SD = 8.8). The average pain level on the numeric analogue pain scale (NAS 0–10) was very low with reported 0.4 points (0-3 points; SD = 1.0).

The average passive and active range of motion of the operated glenohumeral joint was Ext/Flex 30/0/170°, Abd/Add 70/0/20°, and Ero/Iro 60/0/95°. There was no restriction of movement greater than 10° compared to the other side. No significant difference in passive or active range of motion in comparison to the healthy side could be seen. The rotator cuff tests were negative. The anterior apprehension sign was negative in all cases; in one case accompanied by slight pain. Apart from one traumatic redislocation at handball there were no further complications.

4 Discussion

An anatomic reconstruction of the capsulolabral complex is one of the advantages of the described surgical technique. It is possible to address SLAP lesions (Superior labrum anterior to posterior) and rotator cuff tears at the same time. The subscapular muscle or its insertion are not compromised as in an open surgical procedure.

As shown, the arthroscopic Bankart repair using the lasso-loop stitch leads to very good results, which are comparable to other studies of arthroscopic shoulder stabilization with good clinical outcomes.^16–18

Possible disadvantages of the lasso-loop stitch compared to arthroscopic single interrupted or mattress sutures are a relatively demanding and slightly more time-consuming technique, and not being able to use slip knots.

Iatrogenic cartilage damage, misplacement of anchors, or lesions to the axillary nerve can occur intraoperatively; the latter when too much tissue is taken while performing a capsular shift in the anterior inferior recessus.

Malcompliance by the patient with risk to the healing process of the anterior capsulolabral complex with strong tensile forces during external rotation require extensive patient consent and education.

In the event of redislocation a detailed investigation of causes in the patient history and further diagnostics including MRI should take place before possibly attempting renewed stabilization.¹⁹

Postoperative infection requires arthroscopic irrigation and systemic antibiotics, beginning with Ampicillin/Sulbactam and possibly changing to the antibiogram.

If a bony Bankart fragment is big enough to allow screw fixation, this should be undertaken either openly or arthroscopically. If the labrum remains partially unstable, a further labrum reconstruction following screw fixation may be necessary.

The arthroscopic refixation of the capsulolabral complex with suture anchors using the lasso-loop stitch is slightly more elaborate due to the suturing technique than single interrupted sutures or mattress sutures. But this technique leads to a stronger bulging of the glenoid labrum and might therefore increase the physiological bumper effect of the labrum. At the same time the knot can be positioned away from the joint to avoid irritation without cutting through the tissue like it is possible with mattress sutures for glenoid labrum refixation.

For further clarification of possible advantages and disadvantages of this technical modification, prospective studies comparing the described procedure with other stitching techniques are recommended.

In conclusion, using the lasso-loop stitch in arthroscopic Bankart repair is safe and results in very good clinical outcomes. It leads to an accentuated labral bump and enables secure knot tying with positioning of the knot away from the articular cartilage while avoiding the suture cutting through the tissue. Further follow-up is needed to evaluate long-term outcome and possible development of osteoarthritis.

Conflict ofinterest

The authors declare that they have no conflict of interest.