2015 ISAKOS Biennial Congress ePoster #1429

Arthroscopic Treatment of Patella Clunk and Crepitus Syndromes After Posterior Stabilized TKA

Takao Kodama, MD, PhD, Tokyo JAPAN
Hiroshi Shimosawa, MD, Tokyo JAPAN
Shu Kobayashi, MD, PhD, Tokyo JAPAN
Hiroya Kanagawa, MD, Tokyo JAPAN
Toshie Sasaki, MD, Tokyo JAPAN

JCHO Saitama Medical Center, Saitama, Saitama, JAPAN

FDA Status Cleared

Summary: Patella clunk and crepitus syndrome (PCS) is one of the major complications of posterior stabilized TKAs. The implant design has a strong influence on the incidence of the PCS. We have been treating PCS arthroscopically and having successful results. Arthroscopic debridement of fibrous nodules which are seen in PCS are easy and secure method.




Patella clunk and crepitus syndromes (PCS) are one of the major complications of posterior stabilized TKAs. They are caused by fibrous nodule tissues developed at the junction of proximal pole of patella and quadriceps tendon, which impinge against the anterior corner of the box of the femoral component. It may sometimes be painful when standing up from chair, or going up and down the stairs.


The objective of this study is to find the incidence of PCS with PFC sigma RPF, and review the results of our treatment.


Of 414 TKAs done by PFC sigma RPF, there were 11 patella clunk syndrome and 16 patella crepitus syndrome, and overall incidence of PCS was 6.5%. PCS occurred between a month and 6years after TKA with average of 12.8 months. 16 patients needed arthroscopic debridement. The average operation time was 9.3 minutes. 11 patients were treated conservatively because they only had clunk or crepitus without any pain. Out of 11 patients who were treated conservatively, PCS disappeared spontaneously in 7 patients with in 7 months. No patella component was revised in my series. There was no case of recurrence.


PFC sigma RPF has edgy box, which extend more proximally than any other implants. This implant design may be one of the reasons for the fibrous tissue to be impinged against, and the scars may grow larger and cause crepitus and finally start to clunk with popping noise. The operation of PCS is to remove this fibrous nodule existing at proximal part of patella arthroscopically. The arthroscopic operation is very easy, and arthrotomy is not necessary. The symptom immediately disappears after the operation. In 7 patients who were treated conservatively PCS disappeared spontaneously, however this mechanism is uncertain.
To prevent PCS, coagulation and careful removal of soft tissues in proximal part of patella including synovia is necessary during the operation.
Patients with rheumatoid arthritis, PCS tend to occur later (mean, 24.8 months), and patients with osteoarthritis, PCS tend to occur earlier (mean, 11.5months). In rheumatoid arthritis patients, control of disease itself is essential because poor control of the disease may easily cause synovitis that will impinge against femoral box.


PCS is depended on implant design but arthroscopic debridement is effective when the symptom doesn’t disappear within 6 months.