Tag Archive | Oxford Knee Score

Validity of Non-English PROMs to Assess TKA

Patient-reported outcome measures (PROMs) have become increasingly important tools in the 30 years since the orthopaedic community began embracing the movement toward the “patient perspective.” Clinical findings such as range of motion and imaging results remain important, but we have come to understand that pain and function–as reported by the patient–are the most crucial data points. And we are not alone. Insurance companies, registries, scholarly publications, and research review panels now often require PROMs as part of their core evaluations.

But not all PROMs are created equal. For clinicians to trust the output from these instruments, validation of the measures is required. This entails reliability testing and assessment of face, construct, and criterion validity. Furthermore, translating PROMs validated in English into other languages involves not only linguistic translation, but also cultural components in order to capture the full patient perspective.

In the August 5, 2020 issue of The Journal, Bin Sheeha et al. report their work in evaluating the responsiveness, reliability, and validity of the Arabic-language version of the Oxford Knee Score (OKS-Ar). After painstaking statistical analysis of OKS-Ar questionnaires completed by 100 Arabic-speaking patients (80 of whom were female) before and after total knee arthroplasty (TKA), the authors concluded that the OKS-Ar is a valid, sensitive, and easy-to-use instrument to assess pain and function in TKA-treated individuals whose main language is Arabic.

To be truthful, this is not very glamorous research to conduct or very exciting to read about. However, it is absolutely fundamental to ensuring the validity of multicenter, international trials and registry studies. In essence, Bin Sheeha et al. have dug a conduit that facilitates the flow of reliable data and that will help improve future patient care worldwide. As such, it deserves our attention, understanding, and appreciation.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Does Computer-Assisted Surgery Drive Better TKA Outcomes?

Computer-assisted surgery (CAS) for total knee arthroplasty (TKA) has become popular largely based on claims that the technology improves accuracy of component positioning and alignment. Theoretically, that leads to superior patient-reported outcomes. However, the use of CSA has not reliably yielded improvements in implant survival or clinical outcomes. A large registry study by Roberts et al. in the April 1, 2020 issue of The Journal sheds additional light on this perplexing question.

An earlier study by the same author group used data from the same New Zealand Joint Registry and showed no difference in functional outcomes or implant survival between TKAs performed with and without CAS.1 However, that study did not account for the potential bias introduced by surgeons who use CAS only for complex cases.

In this study, Roberts et al. analyzed data from 2 carefully selected groups of surgeons: those who used CAS in 90% of their TKAs (“routine CAS” surgeons) and those who used CAS in <10% of their TKAs (“routine conventional” surgeons). Further limiting their analysis to surgeons with >50 TKAs recorded in the registry between 2006 and 2018, Roberts et al. identified 25 “routine CAS” surgeons and 22 “routine conventional” surgeons. This allowed a comparison between 9,501 TKAs performed by routine CAS surgeons and 7,672 TKAs performed by routine conventional surgeons.  While analyzing revision rates and Oxford Knee Scores (OKS) at 6 months, 5 years, and 10 years, the authors also controlled for confounding variables such as age, body-mass index, and implant type.

With a mean follow-up of 4.5 years, the authors found a revision rate per 100 component-years of 0.437 in the group operated on by routine CAS surgeons, compared to a mean 4.9-year revision rate of 0.440 in the group operated on by routine conventional surgeons (p=0.724).  When stratifying outcomes of patients <65 years old, the authors again found no statistical difference in revision rates. They also found no between-group differences in OKS within the full and <65 cohorts at 6 months, 5 years, or 10 years.

The findings prompt the authors (and I) to wonder whether continually improving design and durability of modern implants make it difficult to discern any advantage from computer assistance in implant positioning.

Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media

Reference

  1. Roberts TD, Clatworthy MG, Frampton CM, Young SW. Does computer assisted navigation improve functional outcomes and implant survivability after total knee arthroplasty? J Arthroplasty. 2015 Sep; 30(9)Suppl: 59-63.

Patellar Resurfacing in TKA: Is There a ‘Right’ Answer?

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