Review Question - QID 219960

The patient has traumatic anterior shoulder instability with minimal anterior glenoid bone loss (<7%) and an "on-track" Hill-Sachs lesion that has a low chance of engaging [HSI = 19mm < glenoid track (GT) = 22.07 mm], making an isolated arthroscopic Bankart procedure the most appropriate procedure for this patient at this time to reduce the risk of recurrence while also minimizing the risk of associated treatment complications (Answer 4).

Traumatic Anterior Shoulder Instability, also referred to as TUBS (Traumatic Unilateral dislocations with a Bankart lesion requiring Surgery), results from traumatic shoulder injuries that generally occur as a result of an anterior force sustained to the shoulder while the arm is in an abducted and externally rotated position. Importantly, an associated Hill-Sachs lesion, which represents a chondral impaction injury to the posterosuperior humeral head secondary to contact with the glenoid rim, occurs in 80-100% of traumatic anterior shoulder dislocations. When this lesion engages the glenoid, also known as an "off-track" lesion, it becomes a clinically significant risk factor for recurrence. Specifically, this occurs when the Hill-Sachs interval (HSI) exceeds that of the glenoid track (Illustration A), which can be calculated from the following equation: Glenoid Track (GT) = 0.83D-d (D = diameter of inferior glenoid, d = width of anterior glenoid bone loss). An "off-track" lesion should be treated at the time of arthroscopic Bankart repair with the addition of a remplissage procedure in order to reduce the HSI to a level that is smaller than the glenoid track.

Yang et al. reviewed the use of remplissage versus modified Latarjet for off-track Hill-Sachs lesions with subcritical glenoid bone loss. The authors looked at 189 patients with recurrent anterior shoulder instability, off-track Hill-Sachs lesion, and less than 25% glenoid bone loss, and found that both arthroscopic Bankart repair with remplissage and modified Latarjet can achieve satisfactory results with the initial surgical intervention in the general population, but that a higher complication rate was observed in the Latarjet group. Despite this, they concluded that Latarjet appears to be a better choice in patients with revision instability surgery, collision and contact athletes, and those with >10% glenoid bone loss.

Cho et al. reviewed the management of engaging Hill-Sachs lesions, comparing the results of arthroscopic remplissage with Bankart repair to those of the Latarjet procedure. The authors compared the results of 72 shoulders and found at final follow-up that postoperative pain, shoulder mobility, muscle strength, Rowe score, and UCLA score revealed no significant difference between the two groups. They concluded that for recurrent anterior shoulder instability with a large engaging Hill-Sachs lesion, both arthroscopic remplissage with Bankart repair and the Latarjet procedure were safe and reliable techniques with a low recurrence rate; however, the Latarjet group had a significantly higher post-operative-complication-rate.

Figure A is an axial STIR MRI sequence showing a Bankart lesion of the anterior labrum, as well as edema and bone loss on the posterosuperior humeral head consistent with a Hill-Sachs lesion. Figures B and C are axial and sagittal T1-weighted MRI sequences showing the Hill-Sachs interval (HSI) measuring 19mm and the glenoid track measuring [(0.83 x 29) - 2 = 22.07 mm], respectively.

Incorrect Answers:
Answer 1: Given that the patient has an "on-track" lesion (HSI < GT; 19mm < 22.07 mm), the lesion is unlikely to engage. The addition of a remplissage in this instance would increase his risk for complications including loss of external rotation associated with the remplissage procedure compared to arthroscopic Bankart alone.
Answers 2 and 3: The patient has sub-critical bone loss (2mm/29mm = 6.89%), thus neither a Latarjet procedure nor distal tibial allograft (DTA) augmentation of the glenoid are indicated as first-line treatments in this scenario. In addition, the surgical risks of both open and arthroscopic Latarjet or DTA far exceed those of arthroscopic Bankart alone.
Answer 5: Though large "off-track" Hill-Sachs lesions can be grafted, this patient has an "on-track," non-engaging lesion that would not require the addition of this extra procedure that comes with a subset of additional possible complications compared to arthroscopic Bankart alone.