Abstract
The purpose of this study was to evaluate the conversion rate of knee arthroscopy
to ipsilateral total knee arthroplasty (TKA) within 2 years in patients aged 50 or
older at the time of arthroscopy. The administrative database from a large, physician-owned
orthopaedic practice (>100 surgeons) was queried to identify patients over the age
of 50 who had undergone arthroscopic knee surgery between January 1, 2006 and January
2, 2015. The subset of patients who converted to TKA within 2 years after knee arthroscopy
was identified and matched by age and sex to a control population that did not convert
to TKA. Rates of conversion to TKA were calculated. Prearthroscopic digital radiographs
were reviewed and Kellgren–Lawrence (KL) grades were compared among case and control
populations. Univariable analyses and multivariable regression analysis were performed.
Eight hundred seven of 16,061 (5.02%) patients aged 50 or older were converted to
TKA within 2 years following ipsilateral knee arthroscopy. In univariable analysis,
the rate of conversion to TKA in patients aged between 50 and 54 was 2.94%, compared
with 4.44% in patients aged between 55 and 64, and 8.32% in patients 65 or older (p < 0.0001). Female sex was associated with a higher rate of conversion to TKA in univariable
analysis (5.93 vs. 4.02% in males, p < 0.0001). KL grades were higher among patients who converted to TKA compared with
those who did not (p < 0.0001). In a multivariable regression model controlling for age, sex, and KL grade,
only increased KL grade was associated with increased odds of conversion to TKA. In
the appropriately selected older patient, the risk of conversion to TKA within 2 years
of knee arthroscopy is low (∼5%). Patients with KL grade 2 or higher at the time of
arthroscopy should be counseled on the increased odds of early conversion to TKA.
Keywords
knee osteoarthritis - knee arthroplasty - knee arthroscopy
