ALPSA lesions
ALPSA is an abbreviation of:
Anterior labroligamentous periosteal sleeve avulsion lesion or Anterior Labral Periosteal Sleeve Avulsion.
Definition and pathology of ALPSA
ALPSA lesion is an injury at the front of the shoulder associated with shoulder dislocation. The anterior labrum and the periosteum are both avulsed. They are folded in a sleeve-like fashion. The anterior labrum is absent on the glenoid rim.
The anterior labrum and periosteum are both medially and inferiorly displaced. They heal in such a non-functional position on the glenoid.
What is the common thing between ALPSA and Bankart lesions?
Both lesions are usually due to anterior shoulder dislocation and they involve the anterior inferior labrum.
The main difference between ALPSA and the antero-inferior labral tear
is that ALPSA consists of a tear of the anteroinferior labrum with associated non disrupted periosteal stripping.
With each time of anterior dislocation, the anteroinferior labrum retracts medially and becomes adherent to the glenoid neck with scarring of the tissue. ALPSA can originate from a Perthes lesion. Traction transmitted along the anterior band of the inferior gleno-humeral ligament strips the periosteum that remains attached to the labrum medially along the glenoid neck.
Why is ALPSA a difficult problem?
ALPSA lesions usually represent a diagnostic and treatment challenge. They are associated with a higher number of preoperative dislocations, as well as longer chronicity, and commonly result in a scarred and medialized labrum and periosteal sleeve complex.
In chronic ALPSA lesions, the torn and medially displaced antero-inferior labrum is seen along the glenoid neck as a low signal mass in MRI. It represents the scarred down labrum held by the periosteal sleeve. It is often rotated inferiorly. It appears larger on axial images, with abnormal thickening and flattening that results from healing with synovial fibrous tissue between the labrum and glenoid margin. Usually a small separation can be observed between the glenoid margin and the labrum. The anterio-rinferior glenoid rim is bare or deficient.
Which one has a higher risk of redislocation ALPSA or Bankart lesion?
ALPSA lesions probably have a higher risk of redislocation than nondisplaced Bankart tears, as the normal tissue and capsule that stabilise the front of the shoulder are displaced and the anterior glenoid is deficient of a capsule and labrum. ALPSA lesions should be repaired early, before they heal into a poor position. Because later repairs require moving the poorly healed labrum back to it's correct position.
Epidemiology
It is usually the result of chronic injury rather than acute dislocation. The incidence increases in patients with multiple dislocations.
Natural history
If ALPSA not treated acutely, it will heal in a non functional medialized position on the glenoid neck, leading to chronic incompetence of the labrum and inferior glenohumeral ligament.
If ALAPSA is not treated, shoulder instability persists and often leads to cartilage damage, glenoid bone loss, and Hill-Sachs lesions.
Clinical picture
the patient may report a history of a traumatic dislocation several months or even years ago. The patient describes that his shoulder has dropped out of its socket . It may occur several times in the last few months.
The manifestations of chronic glenohumeral instability may occur several times. Affected individuals may develop shoulder pain and recurrent shoulder dislocations following the initial one. MRI allows lesion characterisation for the purpose of treatment planning, with the primary goal of stabilisation.
Clinical examination
Physical exam revealed the unstable humeral head in the glenoid labrum with passive range of motion. Also a popping sensation was appreciated by the examiner.
Radiography
X ray
Usually unremarkable, showing no evidence of prior traumatic osseous injury.
MRI
The anteroinferior labrum is displaced medially and still attached to the scapular periosteum.
The anterior glenoid rim is bare, with the detached and medially displaced anterior labrum seen as a low-signal mass attached to the scapular neck by the periosteal sleeve.
The clue to identifying an ALPSA lesion is the medial displacement and inferior shifting of the inferior glenohumeral ligament (IGHL) complex. A Hill-Sachs defect may be seen in association.
MR Arthrography
May show the contrast entering a cleft between the antero-inferior glenoid and the labrum. The labral tissue is detached with the periosteal attachment stripped without tearing. It may reveal avulsion and displacement of the anteroinferior labrum medially from its site of attachment at the glenoid rim with an intact sleeve of periosteum attaching the labrum to the medial scapula .
Treatment
Does ALPSA lesion require surgery?
If required, the labrum and periosteum should be reattached, recreating the bumper effect. That aids shoulder stability and hopefully prevents further dislocation. It can be done by Arthroscopic techniques or with open surgery. Sometimes, the injury cannot be repaired.
Why is ALAPSA difficult to treat?
Because of its associated larger Hill-Sachs lesions. It is also associated with alarger amount of glenoid bone loss. Also there is usually difficulty in restoring the anatomic footprint of the labrum in these medialized and scarred lesions.
The aim of treatment of ALPSA
To achieve complete mobilization of the labral-periosteal complex and restore it to the anatomic location using anchors.
Treatment of ALPSA
Treatment of an ALPSA lesion involves mobilization of the labrum which remains attached to the periosteum overlying the glenoid. As a result, an ALPSA lesion may heal as opposed to a Bankart lesion which does not. Healing occurs in an abnormal position requiring identification and early surgical repair.
Surgical Technique
-The patient is placed in the beach-chair position.
-Diagnostic arthroscopy is done.
-Attention should always be drawn down the glenoid neck if the anteroinferior labrum appears to be absent.
-To better visualize the anterior rim of the glenoid and the ALPSA lesion, a 70° arthroscope
Prognosis of ALPSA
It is worse than the Bankart lesion. The complexity of the injury pattern has been often associated with double the failure rate of standard Bankart lesions after arthroscopic repair.
Differential diagnosis
D. D. shoulder instability
Bankarts lesion
Perthes lesion
Fibrous vs osseous Perthes lesion
SLAP tears
GLAD lesion
Kim lesions
Difference between ALPSA lesion and Bankarts lesion?
Recurrent anterior shoulder instability is not usually associated with a classic Bankart lesion, which is an avulsion of the anterior labroligamentous structures from the anterior glenoid rim. ALPSA lesion differs from the Bankart lesion because the anterior scapular periosteum does not rupture, thereby allowing the labroligamentous structures to displace medially and rotate inferiorly on the scapular neck. These lesions eventually heal, and lead to recurrent anterior dislocations because of the subsequent incompetence of the anterior inferior glenohumeral ligament.
Conversion of the ALPSA lesion to a Bankart lesion
There is an arthroscopic technique that converts the ALPSA lesion to a Bankart lesion
and subsequently reconstructs the supporting anterior inferior structures of the shoulder.
https://www.arthroscopyjournal.org/article/S0749-8063(05)80338-X/pdf
Kim lesions
Kim lesions are superficial tears at the junction between the posteroinferior glenoid cartilage and the labrum It has no complete labral detachment. They are uncommon injuries seen in active adults in association with overhead activities such as volleyball.
Perthes lesion
Perthes lesion of the shoulder is one of the types of the anterior shoulder injury in which the anterior inferior labrum is torn and lifted from the edge of the glenoid but still attached to the intact lifted periosteum.
Although the labrum might be normally positioned, functionally it does not provide stability to the humeral head, mainly as a result of impairment of the normal stabilizing effect of the inferior glenohumeral ligament.
ALAPSA lesions associations
ALPSA may be associated with a higher number of preoperative shoulder dislocations, larger Hill-Sachs lesions and larger amounts of glenoid bone loss in comparison to isolated Bankart lesions.