Hospital for Special Surgery (HSS), the world’s leading academic medical center focused on musculoskeletal health, today announced the results of a retrospective study analyzing the results of the “Quiet Knee” protocol after total knee arthroplasty (TKA), also known as knee replacement surgery. The study results were shared at the American Association of Hip and Knee Surgeons (AAHKS) annual meeting.

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HSS Research Shows “Quiet Knee” Protocol Could Redefine Knee Replacement Recovery

The Quiet Knee protocol, which some HSS surgeons began implementing several years ago, takes a more conservative approach to knee replacement recovery than traditional clinical protocols. This new technique focuses on controlling inflammation and swelling postoperatively through restricted mobility and passive range of motion (ROM) and aggressive cryotherapy (icing) for the first 10 days immediately following surgery. This contrasts with standard protocols, which often emphasize early and aggressive movement that can cause inflammation in surgical tissue that is healing.

All HSS total knee replacement patients from 2020 to 2024 were retrospectively reviewed as part of the study. A Quiet Knee group consisting of 271 patients received structured postoperative care and monitored telerehabilitation. One comparison group was given Quiet Knee guidance verbally, while a second cohort followed traditional early motion postoperative therapy.

“Patients are told they have to work really hard to get motion back after surgery—the no pain, no gain type of mentality,” said Brian P. Chalmers, MD, a hip and knee surgeon at HSS and one of the authors of the study. “The problem with that is that the more patients do in the early period of recovery—the more they bend, the more they are up and walking—the more the knee will swell.”

Every person undergoing TKA experiences pain and swelling after surgery, but the intensity differs, making the patient’s recovery process more challenging and often more painful than most other surgeries.

“It’s not uncommon to see a counterproductive early physical therapy program that is too aggressive,” Dr. Chalmers said. “In these cases, the knee becomes very swollen, which causes patients to have more pain. As the knee becomes more inflamed and patients are able to bend it less, it just becomes a cycle.”

Under the Quiet Knee protocol, patients avoid intensive physical therapy immediately after surgery, allowing the body time to heal before progressing to motion and other strength work. Early results suggest this approach helps set the stage for a smoother long-term recovery. The study also showed that the protocol significantly reduced 90-day opioid exposure by more than 25%.

“This isn't a surgeon-driven protocol or a research-driven protocol. It's a physiology-driven protocol,” said Michael P. Ast, MD, Chief of the Knee Service and Chief Medical Innovation Officer at HSS and co-author of the study. “It is a recognition of what the human body goes through in recovery from surgery. It is a very logical way of respecting the body's inflammatory response to trauma. Early on after surgery, less really is more. That is really the guiding principle of this protocol.”

Study Details

A Retrospective Cohort-Based Analysis of the “Quiet Knee” Protocol After Primary Total Knee Arthroplasty

Pravjit Bhatti, Lauren Moeller, Michael P Ast, Tony Sicheng Shen, Peter Keyes Sculco, David Jacob Mayman, Brian Chalmers

About HSS

HSS is the world’s leading academic medical center focused on musculoskeletal health. At its core is Hospital for Special Surgery, nationally ranked No. 1 in orthopedics (for the 16th consecutive year), No. 3 in rheumatology by U.S. News & World Report (2025-2026), and the best pediatric orthopedic hospital in NY, NJ and CT by U.S. News & World Report “Best Children’s Hospitals” list (2025-2026). In a survey of medical professionals in more than 20 countries by Newsweek, HSS is ranked world #1 in orthopedics for a fifth consecutive year (2025). Founded in 1863, the Hospital has the lowest readmission rates in the nation for orthopedics, and among the lowest infection and complication rates. HSS was the first in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center five consecutive times. An affiliate of Weill Cornell Medical College, HSS has a main campus in New York City and facilities in New Jersey, Connecticut and in the Long Island and Westchester County regions of New York State, as well as in Florida. In addition to patient care, HSS leads the field in research, innovation and education. The HSS Research Institute comprises 20 laboratories and 300 staff members focused on leading the advancement of musculoskeletal health through prevention of degeneration, tissue repair and tissue regeneration. In addition, more than 200 HSS clinical investigators are working to improve patient outcomes through better ways to prevent, diagnose, and treat orthopedic, rheumatic and musculoskeletal diseases. The HSS Innovation Institute works to realize the potential of new drugs, therapeutics and devices. The HSS Education Institute is a trusted leader in advancing musculoskeletal knowledge and research for physicians, nurses, allied health professionals, academic trainees, and consumers in more than 165 countries. The institution is collaborating with medical centers and other organizations to advance the quality and value of musculoskeletal care and to make world-class HSS care more widely accessible nationally and internationally. www.hss.edu.

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