SEATTLE – Arthroscopic Bankart lesion repairs don’t seem to work well in patients who have lost more than 13.5% of their glenoid fossa after dislocating their shoulders; an open inferior capsular shift or Latarjet procedure is likely to be a better bet, according to a review of 72 consecutive soldiers at Tripler Army Medical Center in Honolulu, who had an arthroscopic Bankart repair after shoulder dislocation.
Seven of the 29 patients (24%) who went into the operation with greater levels of bone loss redislocated over an average of about 4 years of follow-up, versus 2 of 37 (5%) who had less than 13.5% of their glenoid fossa missing. When patients who redislocated were excluded, the mean Western Ontario Shoulder Instability (WOSI) score was 43% of normal in the 13.5% or more bone loss group, but about 80% of normal in those who had lost less bone.
In short, bone loss of 13.5% led to "unacceptable clinical outcomes. Patients with bone loss beyond this threshold should be counseled accordingly with consideration for alternative surgical procedures," the investigators concluded.
Surgeons "have to pay a lot more attention to how much bone loss is there. We have traditionally defined the level of bone loss" that triggers an open procedure at 20%. "In today’s world, everybody agrees that 20% is too high, but the" question has been by how much. At 13.5% – judged by preoperative MRI or CT – "two things become clear. They redislocate at too high a level, and they" report too much instability on the WOSI," said lead investigator Dr. John Tokish, now an orthopedic surgeon at the Greenville (S.C.) Health System.
"If you are just evaluating your results based on whether or not the person redislocates, you missed the point. When we evaluate function in these patients with well below 20% bone loss, they have pain and apprehension. Even if their shoulders don’t come out again, these patients are self-limiting," he said.
When arthroscopic Bankart repair is ruled out, Dr. Tokish cautioned, it "doesn’t necessarily mean we should jump right away to a Latarjet," in which the tip of the coracoid process is repositioned to increase glenoid surface area. "Some would argue that a Latarjet is too big a step. An open inferior capsular shift" may be enough, or even superior.
There were 73 operated shoulders in the 72 patients, 68 of whom were men. The average age at surgery was 26.3 years. Glenoid bone loss was calculated by overlaying a circle onto preop images of the fossa. Patients were excluded if they had a previous shoulder operation.
Dr. Tokish had no disclosures. The work was funded internally.