Based on available data, it appears that most arthroplasty surgeons in the United States (myself included) usually resurface the patella during total knee arthroplasties (TKAs). This strategy is supported by much of the orthopaedic literature, but there is no universal consensus on which approach is best. Internationally, surgeons in some countries resurface the patella <20% of the time.
Amid this debate, the March 6, 2019 JBJS study by Maney et al. utilizes the New Zealand Joint Registry to shine a little more light on the issue. After analyzing close to 60,000 primary TKAs performed by 203 surgeons, the authors found that patients who underwent knee arthroplasty by surgeons who “usually” (>90% of the time) resurfaced the patella had significantly higher patient-reported Oxford Knee Scores at both 6 months and 5 years postoperatively, compared to those who had their knee replacements performed by surgeons who “selectively” (≥10% to ≤90% of the time) or “rarely” (<10% of the time) resurfaced the patella. However, only 7% of the surgeons in the study fell into the usually-resurface category. That fact, along with the authors’ inability to account for possible confounding patient or surgeon factors, imparts some fragility to the study’s data. Just as (or even more) importantly, the authors did not find any differences in revision rates per 100 component years between the three resurfacing strategies, with >92% survival for all implants at 15 years postoperatively.
This study seems to support previously published data suggesting that resurfacing the patella yields functional outcomes that are at least as good as, if not slightly better than, those with not resurfacing the patella. Still, added costs and potential complications are associated with patellar resurfacing, and these results could also be used to support the strategy of surgeons who do not routinely perform that part of a total knee arthroplasty.
While we still don’t know the “best” strategy, this study adds further credence to the notion that there is not a “wrong” technique when it comes to resurfacing the patella, and surgeons should continue to use whichever technique they feel is best for individual patients.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
A randomized study of 80 postmenopausal women with mild knee osteoarthritis found that those assigned to a supervised progressive-impact exercise program (including jumping and change-of-movement exercises) thrice weekly for a year experienced more biochemical improvements in their patellar cartilage, as determined by MRI T2 relaxation time, than those in a non-intervention control group. The exercise group also saw greater improvement in muscle strength and aerobic capacity, while patient-reported KOOS-score changes were similar in both groups.
Although many clinicians deem high-impact activity to be contraindicated in this population, this study suggests that postmenopausal women with mild knee OA can, under the supervision of a physical therapist, be encouraged to include high-impact exercises in their fitness regimen.