Patellar clunk syndrome more common with high-flex bearing than fixed-bearing TKA

Patients who underwent total knee arthroplasty with a rotating high-flex bearing had higher rates of patellar clunk syndrome than patients who underwent the procedure with a fixed bearing. However, all patients reported satisfaction with outcomes overall, according to study results.

Researchers assessed 188 high-flex mobile-bearing and 223 fixed-bearing total knee arthroplasties (TKAs) between February 2005 and November 2007 for complications, incidence of patellar clunk, treatment, rates of recurrence, range of motion and patient satisfaction. Mean follow-up duration from index TKA was 8.2 years for the mobile-bearing group and 7.2 years for the fixed-bearing group. No statistically significant demographic differences between the mobile and fixed bearing groups were noted.

The researchers found 22 cases of patellar clunk developed in the mobile-bearing knees, compared with four cases of in fixed-bearing knees. Regardless of group, all patients who developed patellar clunk syndrome underwent 3 months of consecutive treatment followed by arthroscopic surgery. Of the 26 cases, 23 were resolved with only one procedure, and two cases required a second procedure.

All patients but one were reported to be satisfied with the overall results of the index procedure, according to the researchers.

Mean postoperative range of motion did not differ significantly between the groups, according to the researchers. Patients with resolved cases of patellar clunk syndrome had a mean flexion range of 124°, whereas patients without patellar clunk had a flexion range of 123.7°.

Disclosure: See the study for a full list of all authors’ relevant financial disclosures.

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Source:

Snir N. J Arthroplasty. 2014. doi:10.1016/j.arth.2014.05.011.