Early Research Shows Most Patellar Instability Patients Don't Need Advanced Bony Surgery

A first-of-its-kind study led by physician-scientists from Cincinnati Children’s and the Hospital for Special Surgery (HSS) could eventually transform treatment protocols for children, teens and young adults with patellofemoral instability.

The researchers are part of a national collaborative called JUPITER, or Justifying Patellar Instability Treatment by Results. In this latest phase of their research, they aim to identify whether certain patients with a first-time patella dislocation would benefit from early surgical intervention. They also hope to develop a scoring model that helps providers determine what type of surgery each patient with patellar instability needs.

Initial Data Will Pave the Way for Additional Insights

JUPITER is a multicenter, multi-arm prospective cohort study comprised of nearly 30 orthopaedic surgeons at more than a dozen pediatric and adult medical centers. Since 2017, participating surgeons have worked to better understand the risk factors that cause some people to have recurrent patellar instability. They’re also investigating when and how to treat patellar instability to achieve the best long-term outcomes.

“Over the last two decades or so, especially as more kids have begun specializing in single sports at younger ages, we’ve seen an increase in patella dislocations,” says Shital Parikh, MD, FACS, a Cincinnati Children’s orthopaedic surgeon and co-principal investigator of the JUPITER study. “About a third of patients who dislocate their patella experience recurrent instability, and with each recurrence there is an increased risk of cartilage damage that can lead to early osteoarthritis. So it’s very important that we intervene with the right treatment, at the right time.”

Parikh and co-principal investigator Beth Shubin Stein, MD, an HSS orthopaedic surgeon, created the JUPITER study to help address a lack of evidence related to patellar instability treatments and outcomes. Between 2017–2021 alone, investigators enrolled more than 2,000 patients with patellar instability who will be followed at intervals for 10 years.

During that first phase of research, patients were divided into two overall groups: those with first-time dislocations and those with recurrent instability.

Then, they were further divided into one of three treatment arms, chosen by their physician:

• A nonoperative treatment arm
• A surgical treatment arm where patients received isolated medial patellofemoral ligament (MPFL) reconstruction
• A surgical treatment arm where patients received MPFL reconstruction plus additional bony surgery

“One of the key takeaways from that five-year study is that soft tissue surgery alone was sufficient for most patients, even for those who had bony problems,” Parikh says.

In their newest phase of research, called JUPITER 4.0, Parikh and his colleagues will build upon these findings. Given that advanced bony surgery requires a much longer rehabilitation and recovery period—and comes with an increased risk of postoperative complications—they hope to distinguish which patients truly need it.

Predicting Who Needs Early Surgery or Advanced Surgery

JUPITER 4.0 launched in 2023 and is partially funded by a $400,000 grant from the American Orthopaedic Society for Sports Medicine. For this study, investigators plan to enroll an additional 850 patients who need treatment for patellar instability. Each patient will undergo MPFL reconstruction only.

“Because we’re following these patients, we can see if any develop recurrent instability after having soft tissue surgery,” Parikh says. “Among those patients, we can see if they share any characteristics that may contribute to MPFL reconstruction failure. And this may help us create a treatment algorithm that identifies which patients truly need the additional bony surgery.”

The team’s collective data also could be used to refine treatment protocols for people with first-time patella dislocations.

“Today the standard treatments for a first-time dislocation are nonoperative; surgery is reserved for those with recurrent instability,” Parikh explains. “We’re hoping we also can pinpoint the factors that increase the risk of recurrent instability. If we can identify those who would benefit from early surgery, and prevent the subsequent dislocations that can lead to long-term damage, it would be a significant shift in how we treat that specific population.”

(Published November 2024)

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