This review covers the diagnosis and management of acute traumatic posterior shoulder dislocation. It addresses why the injury is so often missed and how reverse Hill-Sachs lesion size guides treatment. It also details the associated injuries and the surgical algorithm from closed reduction to arthroplasty.
When you see a shoulder that will not externally rotate after a seizure, electrocution, or high-energy fall, think posterior dislocation until proven otherwise. The injury is missed in up to 79% of patients because the AP film can look nearly normal. The single most useful step is ordering an axillary or Velpeau view, and looking for the lightbulb sign, trough line, and loss of the half-moon sign.
Once reduced, the reverse Hill-Sachs lesion size becomes your decision engine. Under 20% may tolerate closed or open reduction. From 20% to 40% consider a McLaughlin or modified McLaughlin transfer or bone grafting. Over 40% in a younger patient often needs hemiarthroplasty.
Always image before any reduction maneuver, because reducing an unrecognized neck fracture or forcing an engaged lesion can fracture the head and precipitate osteonecrosis. Finally, if CT shows no fracture, the odds of a rotator cuff tear jump 4.6-fold, so get an MRI.
This review covers the diagnosis and management of acute traumatic posterior shoulder dislocation. It addresses why the injury is so often missed and how reverse Hill-Sachs lesion size guides treatment. It also details the associated injuries and the surgical algorithm from closed reduction to arthroplasty.
When you see a shoulder that will not externally rotate after a seizure, electrocution, or high-energy fall, think posterior dislocation until proven otherwise. The injury is missed in up to 79% of patients because the AP film can look nearly normal. The single most useful step is ordering an axillary or Velpeau view, and looking for the lightbulb sign, trough line, and loss of the half-moon sign.
Once reduced, the reverse Hill-Sachs lesion size becomes your decision engine. Under 20% may tolerate closed or open reduction. From 20% to 40% consider a McLaughlin or modified McLaughlin transfer or bone grafting. Over 40% in a younger patient often needs hemiarthroplasty.
Always image before any reduction maneuver, because reducing an unrecognized neck fracture or forcing an engaged lesion can fracture the head and precipitate osteonecrosis. Finally, if CT shows no fracture, the odds of a rotator cuff tear jump 4.6-fold, so get an MRI.