Shoulder instability index helps predict athletes' nonoperative treatment outcomes

The NISIS should now be evaluated using longer follow-up

NEW ORLEANS — When used in high school athletes, the nonoperative instability severity index score showed athletes with anterior shoulder instability and certain other factors were more likely to achieve successful outcomes with nonoperative treatment, according to results presented at the American Academy of Orthopaedic Surgeons Annual Meeting.

“Most high school … athletes were successful at returning to complete, not only their current season, but a subsequent season, without surgical intervention and without any time lost due to reinjury of their shoulder,” John M. Tokish, MD, senior associate consultant and professor of orthopedic surgery at Mayo Clinic, Arizona, told Orthopedics Today. “Further, we were able to create a score that would accurately predict which ones of those athletes were at risk for failure with this nonoperative management.”

Validating the NISIS

Tokish and colleagues used the nonoperative instability severity index score (NISIS) to determine the optimal score that would predict failed nonoperative management among 57 scholastic athletes.

“We also defined success fairly critically,” Tokish said at the meeting. “In order to be classified as successful, you had to return and complete the entire season subsequently without surgery or any time lost, either practice or game, due to an injury to the index shoulder.”

Tokish noted age greater than 15 years, bone loss, type of instability, participation in collision sports, male gender and arm dominance was associated with a greater risk of recurrent shoulder instability after nonoperative treatment. When investigators placed these risk factors into the NISIS, they found 79% of athletes had successful nonoperative treatment.

Tokish said 97% of patients with a NISIS score less than 7 points completed a subsequent season without loss of time.

Surgery avoided

“The most surprising part of this paper was that when we applied this to a high school athletic population… almost 80% of them never came to surgery and, in fact, went back and completed their seasons without missing any time, which was much higher than is generally thought of,” Tokish said.

In his presentation, Tokish said there was a 40% failure rate among athletes with a NISIS score greater than or equal to 7 points and a 12.2-times higher risk of failure among athletes with a high vs. low NISIS score. Furthermore, 60% of athletes with a high NISIS score had a successful return to sport, he said, noting bone loss was the major risk factor for failure.

“In patients who had no bone loss or unipolar bone loss, they were able to return even with a high NISIS score,” Tokish said. “But if those patients had bipolar bone loss, 67% failed.”

Further evaluation

A weakness of the study was instability episodes were identified using radiographic evaluations and were “qualitatively defined as either it was present or not present,” which is not a quantitative evaluation, according to Tokish.

“However, this limitation actually improves the external validity of the paper because most high school kids who sustain a first-time instability do not get those sorts of advanced imaging and so most physicians and treating providers are making these decisions based upon X-ray, which in our study we were able to use,” he said.

Tokish noted it is important to now validate the NISIS using MRI or CT scans to more specifically evaluate bone and to do that with longer follow-up.

“We only followed out patients for 1 year. So, it is possible that during the second season afterwards… their results may have not been sustainable,” he said. – by Casey Tingle

Reference:

Tokish JM, et al. Paper #696. Presented at: American Academy of Orthopaedic Surgeons Annual Meeting; March 6-10, 2018; New Orleans.

For more information:

John M. Tokish, MD, can be reached at 13400 E. Shea Blvd., Scottsdale, AZ 85259; email: jtoke95@aol.com.

Disclosure: Tokish reports no relevant financial disclosures.