Arthroscopic Latarjet

latarjet

Introduction

The Arthroscopic Latarjet Procedure has successfully treated anterior shoulder instability over the last 9 years and the technique continues to evolve. Although it is associated with a rather steep learning curve, the relatively recent introduction of a customized instrumentation kit has further simplified the crucial steps to make the procedure more reliable and reproducible.
There are, however, still many pitfalls to avoid and the operation remains one for skilled arthroscopic surgeons. We present the indications for this procedure, our current technique in 7 steps and highlight the pearls and pitfalls of this procedure.

Indications

After a detailed history, clinical examination and radiologic investigations are performed, we have found a Latarjet procedure is appropriate in the following clinical scenarios:

1]   Instability with glenoid bone loss

This common cause for recurrent instability can be manifested by an avulsion type bony Bankart lesion or a true fracture of the anterior or inferior glenoid rim. Standard
Antero-posterior x-ray images may show a fracture or a more subtle loss of contour of the Antero-inferior glenoid rim. A decrease in the apparent density of the inferior glenoid line often signifies an erosion of the glenoid rim between 3 and 6 o’clock. An axillary or Bernageau view may show flattening of this area of the glenoid when bone loss has occurred.

Computed tomography (CT) provides a more detailed image, which is essential to be able to quantify the bone loss preoperatively.1 CT reconstructions provide a more robust static measurement than those afforded by the arthroscopic view. To evaluate glenoid bone loss arthroscopically, the distance from the glenoid rim to the bare spot can be measured. This can assist the surgeon in identifying an inverted pear glenoid, confirming substantial bone loss and the likely failure of an isolated soft-tissue repair.2 Even when the bony fragment is present, replacing it is not always sufficient to restore the bony glenoid articular arc, especially where recurrent episodes of instability have further eroded the remaining glenoid edge.3 There are also issues regarding healing in this potentially necrotic bone.4 In these cases, a bony reconstruction should be considered.

2]   Instability with humeral bone loss

The location and size of the Hill-Sachs lesion determines whether the articular arc is reduced and whether this will engage on the glenoid. A dynamic arthroscopy with the shoulder in abduction and external rotation will demonstrate whether the lesion is engaging during an athletic overhead range of movement. A bone-block procedure will increase the arc of the anterior glenoid, thereby increasing the degree of external rotation that can be achieved before the lesion approaches the glenoid rim. An alternative to this would be the infraspinatus and posterior capsule remplissage (French for ‘‘to fill in’’) procedure, as described by Purchase et al.5 We consider that by enlarging the glenoid articular arc with a bone graft, there is no increased joint contact pressure during external rotation. A remplissage can lead to a decrease in the external rotation and give rise to increased contact forces on the articular cartilage during external rotation.

3]   Combinations of glenoid and humeral bone loss

These two lesions usually occur in tandem with varying degrees of severity. Preoperative x-ray images and CT scans usually detect the lesions, but arthroscopic dynamic evaluation of stability is necessary to determine the likely clinical effects of this combination.

4]   Complex soft-tissue injury

HAGL lesions can be diagnosed on preoperative CT, arthrograms or MRI; however, these injuries are often not discovered until the initial arthroscopic evaluation.
Numerous techniques are described for the arthroscopic repair of HAGL lesions, but most case series are small with only short follow-up periods. Our experience using an all-arthroscopic soft-tissue repair technique with anchors has been disappointing due to the postoperative stiffness experienced by some patients. Furthermore, the intrinsic structure of the glenohumeral ligaments is usually deranged in patients with multiple dislocations, although this may not be evident macroscopically. Simply repairing this damaged tissue to the glenoid does not restore stability to the shoulder. This has been likened to rehanging a baggy or incompetent hammock.

5]   Revision of a Bankart repair

This initial procedure may fail acutely for any of the previously mentioned reasons; however, we also have found a second group of patients in whom the Bankart repairs appeared successful but who presented with recurrent instability 5 to 7 years postoperatively. In this subgroup, the joint was not sufficiently stabilized initially, but it does allow for functioning of a more sedentary lifestyle without overt symptoms of instability. This can partly explain the excellent results seen in series with a short follow-up. Although the initial operations were considered successful in these patients, the pathologic lesions were never truly corrected and the glenoid subsequently becomes increasingly eroded. These patients can be effectively managed with a bone-block ligamentoplasty.

6]   Patient activity

Patients engaged in high-risk sports (climbing, rugby) or occupations (carpentry), or who have a high risk of recurrence due to the intensity and action of their activity (throwers), are ideal candidates for the Latarjet procedure. The advantages of this technique include the ability to recreate a stable shoulder with a reduced rehabilitation time to return to full activity.

7]   Current Technique

The current technique involves 7 steps of the operation, which will be highlighted following the patient preparation.

8]   Patient Preparation

General anesthesia with inter-scalene block, alternatively an intra-operative plexus block can be applied.Patient placement in beach chair position without traction Cerebral blood flow measurement during the entire procedure Skin marks including marking the joint axis for later M portal placement

The seven steps of the arthroscopic Latarjet procedure  [ ALP ]  are:

  • Joint evaluation & final decision-making
  • Shoulder exposure & preparation
  • Coracoid preparation & osteotomy
  • Subscapularis split
  • Graft harvest
  • Coracoid transfer & scapula positioning
  • Graft fixation