Philadelphia 76ers

Expert medical analysis on 76ers' All-Star Ben Simmons' reported knee injury and procedure

According to multiple reports, Philadelphia 76ers All-Star Ben Simmons has undergone surgery on his left knee after sustaining an injury against the Washington Wizards during the seeding game schedule.

ESPN's Adrian Wojnarowski reported that Simmons returned to Philadelphia for the procedure and is expected to miss the rest of the season.

With a number of questions surrounding the nature of Simmons' injury and reported procedure, we reached out to our medical expert, orthopedic surgeon Dr. Michael S. George of the KSF Orthopaedic Center in Houston, Texas, to learn more.

On the injury itself and the anatomy of the knee

"Ben Simmons of the 76ers will have arthroscopic surgery on his left knee to remove a loose body caused by a patella - or kneecap - subluxation suffered in the game against the Wizards. The patella normally rides in the groove of the femur called the trochlea and is stabilized by the quadriceps muscles, primarily the vastus medialis (VMO) and the deep ligaments, primarily the medial patellofemoral ligament (MPFL)."

"A subluxation meant the patella went partially out of the groove and went back in on its own, which is different than a dislocation, where the patella goes completely out of the groove and has to be pushed back in. A patella subluxation or dislocation almost always results in an injury to the MPFL. The majority of the time, the MPFL scars-in adequately to the point that recurrent instability does not occur."

On the rehabilitation process

"Rehab after an instability episode typically involves restoring knee range of motion and strengthening of the quadriceps muscles. While not typically the case in NBA players, in some patients, the scar tissue and rehab do not stabilize the patella and recurrent instability can ensue, which then requires surgical reconstruction."

What is a 'loose body'? And what will the procedure entail?

"Unfortunately, in Simmons' case, the patella subluxation was forceful enough that a piece of cartilage - with or without bone - was knocked off and needs to be removed. The arthroscopic loose body removal procedure is an outpatient procedure, after which he will most likely be able to weight bear right away with gradual increase in activity."

"This is, of course, unless his doctors find additional damage that needs to be addressed during surgery. Recovery is usually in the four-to-six week range. He would be expected to have a very good short-term recovery."

Is there cause for bigger picture concern?

"The biggest question mark is what will be the long-term consequences of the injury to the joint cartilage? If the loose body is small, then there may be minimal long-term consequences but if the loose body is large, then it may have a greater impact. His game is so dependent on his athleticism and he will need to have his explosiveness and agility for the long-term."

The views on this page do not necessarily reflect the views of the NBA or its clubs.

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