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Eschew the “Quick Fix” Approach to Early Knee OA

OrthoBuzz occasionally receives posts from guest bloggers. In response to a recent study in Arthritis Care & Researchthe following commentary comes from Jeffrey B. Stambough, MD.

As orthopaedic surgeons, we share a collective objective to help patients improve function while minimizing pain. When patients come to our office for a new clinical visit for knee osteoarthritis (OA), we spend time getting to know them and gathering information about their activities, limitations, and functional goals. We balance this patient-reported information with discrete data points, such as weight, range-of-motion restrictions, and radiographic disease classification. Based on the symptom duration and other factors, most patients are not candidates for a knee replacement at this first visit. However, despite the publication of clinical practice guidelines for the nonoperative management of knee OA in 2008, with an update in 2013, significant variation exists in how orthopaedists treat these patients.

This guideline–practice disconnect is emphasized in findings from a recent study in Arthritis Care & Research that examined nonoperative knee OA management practices during clinic visits between 2007 and 2015. The authors found that the overall prescription of NSAID and opioid medications increased 2- and 3-fold, respectively, over that time, while recommendations for lifestyle interventions, self-directed activity, and physical therapy decreased by about 50%.

To me, the most troubling finding from this study is the sharp increase in narcotic prescriptions, because recent evidence demonstrates that narcotics do not effectively treat arthritis pain. Moreover, for patients who go on to arthroplasty, recent studies have found that preoperative opioid use portends worse postsurgical outcomes in terms of higher revision rates,  worse function scores, and decreased knee motion.

The findings from this study also speak to a larger societal issue for doctors and patients alike: the desire for a “quick fix.”  Despite the time pressure from increasing EHR documentation burdens, dwindling reimbursements, or lack of local resources, we owe it to our patients to counsel them on lifestyle modifications and self-management strategies to help them stay mobile, lose weight (if necessary), and take charge of their joint health. As orthopaedic surgeons, we must continue to strive to de-emphasize opioid pain medication when treating knee OA patients and support them in a holistic manner to ensure their overall health and the function and longevity of their native knee joint.

Jeffrey B. Stambough, MD is an orthopaedic hip and knee surgeon, an assistant professor of orthopaedic surgery at University of Arkansas for Medical Sciences, and a member of the JBJS Social Media Advisory Board.

MRI for Detecting Rapidly Progressive Knee OA: No Crystal Ball

This post comes from Fred Nelson, MD, an orthopaedic surgeon in the Department of Orthopedics at Henry Ford Hospital and a clinical associate professor at Wayne State Medical School. Some of Dr. Nelson’s tips go out weekly to more than 3,000 members of the Orthopaedic Research Society (ORS), and all are distributed to more than 30 orthopaedic residency programs. Those not sent to the ORS are periodically reposted in OrthoBuzz with the permission of Dr. Nelson.

Knee osteoarthritis (KOA) typically develops over a decade or more. However, 1 in 5 people with KOA have more pain and disability at onset, have accelerated radiographic knee osteoarthritis (AKOA), and experience end-stage disease within 4 years. The use of demographics and clinical findings has resulted in only a 40% rate of correctly classifying patients who will develop AKOA instead of longer-term KOA.

Investigators recently conducted a case–control study using data from the OsteoArthritis Initiative (OAI), including demographic, clinical, and biochemical data, along with radiographic and magnetic resonance (MR) imaging data.1 The researchers hypothesized that the addition of an MR imaging-based scoring system would more accurately identify patients at risk for AKOA. They used classification and regression tree (CART) models to assess the ability of baseline MR features to classify participants who will develop AKOA and whether adding baseline MR features to an existing model improved classification of adults who will develop AKOA.

The existing model consisted of clinical data that included pain, function, physical exam findings, and quality-of-life measures. Demographic data included age, sex, and BMI collected at baseline. Biochemical data included high-sensitivity C-reactive protein and serum blood sugar. Data obtained from MR imaging scores included bone marrow lesion volume, effusion-synovitis volume, cartilage damage index, meniscal extrusion and degeneration, cruciate ligament degeneration, and patellar fat pad changes.

Contrary to the hypothesis, the CART models with and without MR features each explained approximately 40% of the variability. Adding MR-based features to the model improved specificity (0.90 vs. 0.82), but lowered sensitivity (0.62 vs. 0.70). Interestingly, the authors found that serum glucose, effusion-synovitis volume, and cruciate ligament degeneration were statistically important variables in classifying individuals who are likely to develop AKOA.

The clinical take home is that early MR data may be useful in sorting out mechanical complaints, but not in determining who will develop AKOA. In contrast, in later stages of KOA, MR images may reveal far greater damage than can be detected on radiographs.

Reference

  1. Price LL, Harkey MS, Ward RJ, MacKay JW, Zhang M, Pang J, Davis JE, McAlindon TE, Lo GH, Amin M, Eaton CB, Lu B, Duryea J, Barbe MF, Driban JB. Role of Magnetic Resonance Imaging in Classifying Individuals Who Will Develop Accelerated Radiographic Knee Osteoarthritis. J Orthop Res. 2019 Nov;37(11):2420-2428. doi: 10.1002/jor.24413. Epub 2019 Jul 29. PMID: 31297900

Association ≠ Causation: Are Steroid Injections for OA Risky?

A recent report in Radiology citing possible complications from injecting steroids into painful joints with osteoarthritis (OA) has received lots of attention in the mainstream media. Radiologists from Boston, Germany, and France reviewed the existing literature and found an association between intra-articular steroid injections and a small increased risk of four adverse joint findings: accelerated OA progression, subchondral insufficiency fracture, complications from osteonecrosis, and bone loss. However, the study did not include a control group that did not receive injections, and therefore it cannot be used to assess whether injections are associated causally with the adverse joint findings.

In an interview with Boston radio station WBUR, lead author Ali Guermazi, MD stressed the point that readers should not conclude from this report that steroid injections cause these complications, adding that additional research in this area is “urgently needed.” In the same radio coverage, Jeffrey Katz, MD, a professor of orthopaedic surgery at Boston’s Brigham & Women’s Hospital and a Deputy Editor at JBJS, said patients who have received such injections or plan to should not be overly worried. However, he added that “for clinicians and patients who’ve been doing injections for several years, it’s worth it to pause and say, ‘Do we want to discuss [again] what we think are the benefits and risks of this.’”

ACL Grafts: Diameter Does Matter, Sort Of

Clinical failure of anterior cruciate ligament (ACL) reconstructions continues to be a too-common scenario. The increasing incidence of ACL revision is due to a variety of factors, including greater intensity of postsurgical physical activity, technical issues, and anatomical influences of the proximal tibia and distal femur. Registries are important sources of data for ACL-related investigations, but I think they are most useful in clarifying experimental designs for more sophisticated clinical research.

In a cohort study in the October 16, 2019 issue of The Journal, Snaebjornsson et al. examined the influence of ACL graft diameter on the risk of revision surgery over 2 years in >18,000 subjects whose data resided in the national knee ligament registries of Sweden and Norway. The vast majority of those patients (92.8%) received a hamstring autograft, with 7.2% receiving a patellar tendon autograft. Overall, the 2-year rate of ACL revision was 2.63% for patellar tendon autografts and 2.08% for hamstring autografts, a statistically nonsignificant difference in relative risk.

However, the authors found an important correlation between graft diameter in the hamstring tendon cohort, with autografts <8 mm in diameter being associated with a higher risk of revision, compared with larger-diameter hamstring autografts. Additionally, patients treated with hamstring graft diameters of ≥9 mm or ≥10 mm had a lower risk of ACL revision surgery than those treated with patellar tendon grafts of any size.

One key limitation that should influence our interpretation of this study is a lack of detail regarding how compliant surgeons were intraoperatively with the use of the measurement device that is depicted in the manuscript and shown above. In addition, the limitations of registry data did not permit the authors to adjust for postsurgical exposures, such as return to sport, the increasing intensity of which makes rerupture more likely. Additional relevant information that would have aided interpretation of the findings includes the relative size of the tibia and femur, lateral condyle size and shape, and proximal tibial slope.

Despite these limitations, this study should prompt further research that uses robust clinical designs to more fully investigate the impact of graft diameter on ACL rerupture rates.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Surgeon Volume Matters for TKA Alignment

The retrospective multicenter study of 1,570 primary total knee arthroplasties (TKAs) by Kazarian et al. in the October 2, 2019 issue of JBJS focused on evaluating the impact of surgeon volume and training status on implant alignment. But the most surprising (and concerning) finding was that even among high-volume attendings—the best-performing of the three surgeon cohorts studied—the proportion of TKA alignment “outliers” was still high.

The authors radiographically measured 3 postoperative TKA alignment parameters: medial distal femoral angle (DFA), medial proximal tibial angle (PTA), and posterior tibial slope angle (PSA). Using established thresholds for “outliers” and “far outliers” for those 3 measurements, the authors compared the radiographic findings among surgeries performed by high-volume attendings (≥50 TKAs/year), low-volume attendings (<50 TKAs/year), and trainees (supervised residents or fellows).

As has been shown in similar studies of total hip arthroplasty (THA), the group of high-volume attendings outperformed the low-volume attendings and the trainee group on nearly all measurements assessed in this study. Interestingly, in terms of TKA alignment, the low-volume attending group and the trainee group performed similarly.

Kazarian et al. express concern that “even the most accurate cohort in our study, [the high-volume attendings], placed only 69.0% of knees in optimal alignment for all 3 measurements.” While the authors admit that implant alignment is not a perfect proxy for clinical outcomes, they argue that “gross alignment outliers are likely to have an impact on knee function, kinematics, and wear characteristics.” Citing literature suggesting that the use of robotic-arm assistance may improve TKA alignment, the authors surmise that employing such technology to assist low-volume surgeons or trainees might optimize alignment and improve outcomes, despite the added up-front cost of the technology.

Expanded Indications for Medial UKA?

Along with recently renewed interest in unicompartmental knee arthroplasty (UKA) has come debate as to whether the preoperative presence of patellofemoral osteoarthritis (OA) and/or abnormal patellofemoral alignment should be considered UKA contraindications. Findings from a retrospective review of 639 knees by Burger et al. in the September 18, 2019 issue of The Journal of Bone & Joint Surgery strongly suggest that the answer is “no.”

After examining preoperative radiographic OA and alignment characteristics and postoperative patient-reported outcomes among patients who underwent fixed-bearing medial UKA, the authors concluded that “neither the [radiographic] presence of preoperative mild to moderate [patellofemoral] osteoarthritis nor abnormal patellar tilt or congruence compromised [patient-reported knee and patellofemoral-specific] outcomes at intermediate-term follow-up [mean of 4.3 ±1.6 years].”

Expanding the surgical inclusion criteria for UKA based on these findings could increase the number of patients eligible for UKA by 20% to 40%, estimated Burger et al. In the practice of the senior author (Andrew D. Pearle, MD), patients with symptoms of patellofemoral OA (such as anterior knee pain with prolonged sitting or stair-climbing) are considered ineligible for UKA, prompting the authors to suggest that “the presence of such symptoms may be better than radiographic criteria for determining which patients are eligible for medial [UKA].”

Morbidly Obese Patients Should Lose ≥20 Pounds Prior to TKA

The obesity epidemic continues throughout much of the developed world. Among the morbidly obese (BMI ≥40 kg/m2), we have a group of patients in whom arthritis is very likely to develop due to excessive loading of articular cartilage, chronic inflammation, and alignment problems. At the same time, many arthroplasty surgeons are wary of treating morbidly obese patients with surgery because of the increased perioperative risks. Although many of these patients still benefit greatly from joint replacement, in today’s “value-based care” environment, some institutions have implemented BMI cutoff thresholds for performing knee or hip arthroplasty. Others have set weight-loss requirements before they will schedule lower-extremity arthroplasty for morbidly obese patients. One still-unanswered question along these lines is: how much weight does a morbidly obese patient need to lose preoperatively in order to improve the outcome after a knee replacement?

Keeney et al. address that question in the August 21, 2019 issue of The Journal. In a retrospective cohort study, the authors evaluated outcomes among 203 morbidly obese patients who underwent a total knee arthroplasty (TKA). They found that a loss of 20 pounds preoperatively was associated with a shorter length of stay and a lower chance of being discharged to a rehab or skilled nursing facility rather than home. However, a 20-pound weight loss had no impact on surgical time or functional outcomes, as measured with the PROMIS-10 physical component score. Of note, only 14% of the evaluated patients lost at least 20 pounds preoperatively (highlighting the difficulty of losing weight in general and among this patient population in particular). There were no benefits of any kind in patients who lost only 5 or 10 pounds preoperatively.

While this study’s sample size is small, the findings provide evidence surgeons can use to encourage (or insist upon) larger amounts of weight loss before arthroplasty procedures in morbidly obese patients. In this study, the patients who lost at least 20 pounds remained morbidly or severely obese, and all the patients eventually regained most or all of the weight they lost. Still, the conclusion that at least 20 pounds of weight loss is beneficial for morbidly obese patients prior to a TKA remains sound. Because of the magnitude of this public health issue, we need more high-quality outcomes research (preferably using more knee-specific functional measures) on preoperative management of morbidly obese patients who are considering lower-extremity arthroplasty.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Good Outcomes and Savings with Preferred-Vendor Program

It has been said that outcomes of total joint arthroplasty are 90% related to surgeon factors (such as prosthetic alignment and fit and soft-tissue management), and only 10% to the implant itself. Historically, surgeon choices of implants for primary total hip and total knee arthroplasty have been based on influences such as the prostheses used during training, prior vendor relationships, specific patient characteristics, and findings in published literature. Absent evidence that the selection of prosthesis vendor affects patient outcomes to any significant degree, and with the universal focus on lowering health care costs, surgeon implant/vendor preferences have come under close scrutiny.

In the August 7, 2019 issue of The Journal, Boylan et al. study the impact of a voluntary preferred single-vendor program at a large, high-volume, urban orthopaedic hospital with >40 (mostly hospital-employed) arthroplasty surgeons. The hospital’s use of hip and knee arthroplasty implants from the preferred vendor rose from 50% to 69% during the program’s first year. In addition, the mean cost per case of cases in which implants from the preferred vendor were used were 23% lower than the mean cost-per-case numbers from the previous year (p<0.001). Boylan et al. noted that low-volume surgeons adopted the initiative at a higher rate than high-volume surgeons, and that surgeons were more compliant with using the preferred vendor for total knee implants than for total hip implants.

Why is it that some higher-volume surgeons seem resistant to change? It is not clear from the data presented in this study whether the answer is familiarity with an instrument system, loyalty to local representatives, or relationships with manufacturers based on financial or personal connections. The authors observed that “collaboration between surgeons and administrators” was a critical success factor in their program, and interestingly, the 3 highest-volume surgeons in this study (who performed an average of ≥20 qualifying cases per month) all used total knee implants from the preferred vendor prior to the initiation of this program.

The provocative findings from this and similar studies lead to many questions ripe for further research. Because hospitals are highly motivated to reduce implant costs in the bundled-payment environment, preferred-vendor programs are gathering steam. We need to better understand how they work (or don’t) for specific surgeons, within surgical departments, and within hospital/insurance systems in order to evaluate their effects on patient outcomes and maximize any cost benefits.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

What’s New in Musculoskeletal Infection 2019

Every month, JBJS publishes a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of all OrthoBuzz Specialty Update summaries.

This month, Thomas K. Fehring, MD, co-author of the July 17, 2019 What’s New in Musculoskeletal Infection,” selected the five most clinically compelling findings—all focused on periprosthetic joint infection (PJI)—from among the more than 90 noteworthy studies summarized in the article.

Preventive Irrigation Solutions
–An in vitro study by Campbell et al.1 found that the chlorine-based Dakin solution forms potentially toxic precipitates when mixed with hydrogen peroxide and chlorhexidine. The authors recommend that surgeons not mix irrigation solutions in wounds during surgery.

PJI Diagnosis
–A clinical evaluation by Stone et al. showed that alpha-defensin levels in combination with synovial C-reactive protein had high sensitivity for PJI diagnosis, but the alpha-defensin biomarker can lead to false-positive results in the presence of metallosis and false-negative results in the presence of low-virulence organisms.

–In an investigation of next-generation molecular sequencing for diagnosis of PJI in synovial fluid and tissue, Tarabichi et al. found that in 28 revision cases considered to be infected, cultures were positive in only 61%, while next-generation sequencing was positive in 89%. However, next-generation sequencing also identified microbes in 25% of aseptic revisions that had negative cultures and in 35% of primary total joint arthroplasties. Identification of pathogens in cases considered to be aseptic is concerning and requires further research.

Treating PJI
–A multicenter study found that irrigation and debridement with component retention to treat PJI after total knee arthroplasty had a failure rate of 57% at 4 years.2

–Findings from an 80-patient study by Ford et al.3 challenge the assumption that 2-stage exchanges are highly successful. Fourteen (17.5%) of the patients in the study never underwent reimplantation, 30% had a serious complication, and of the 66 patients with a successful reimplantation, only 73% remained infection-free. Additionally 11% of the patients required a spacer exchange for persistent infection.

References

  1. Campbell ST, Goodnough LH, Bennett CG, Giori NJ. Antiseptics commonly used in total joint arthroplasty interact and may form toxic products. J Arthroplasty.2018 Mar;33(3):844-6. Epub 2017 Nov 11.
  2. Urish KL, Bullock AG, Kreger AM, Shah NB, Jeong K, Rothenberger SD; Infected Implant Consortium. A multicenter study of irrigation and debridement in total knee arthroplasty periprosthetic joint infection: treatment failure is high. J Arthroplasty.2018 Apr;33(4):1154-9. Epub 2017 Nov 21.
  3. Ford AN, Holzmeister AM, Rees HW, Belich PD. Characterization of outcomes of 2-stage exchange arthroplasty in the treatment of prosthetic joint infections. J Arthroplasty.2018 Jul;33(7S):S224-7. Epub 2018 Feb 17.

Delaying Knee Replacement: Driven to Distraction?

This post comes from Fred Nelson, MD, an orthopaedic surgeon in the Department of Orthopedics at Henry Ford Hospital and a clinical associate professor at Wayne State Medical School. Some of Dr. Nelson’s tips go out weekly to more than 3,000 members of the Orthopaedic Research Society (ORS), and all are distributed to more than 30 orthopaedic residency programs. Those not sent to the ORS are periodically reposted in OrthoBuzz with the permission of Dr. Nelson.

Some symptomatic patients with knee osteoarthritis (OA) present relatively early in the radiographic disease process, while others present after serious articular cartilage loss has occurred. In either case, young knee OA patients are often looking for ways to get relief while postponing a total knee arthroplasty (TKA).

One such recently introduced alternative is knee joint distraction (KJD), a joint-preserving surgery used for bicompartmental tibiofemoral knee osteoarthritis or unilateral OA with limited malalignment. Significant long-term clinical benefit as well as durable cartilage tissue repair have been reported in an open prospective study with 5 years of follow-up.1 A more recent study of distraction2 presents 2-year follow-up results of a 2-pronged trial that measured patient-reported outcomes, joint-space width (JSW), and systemic changes in biomarkers for collagen type-II synthesis and breakdown.

In one arm, end-stage knee OA patients who were candidates for TKA were randomized to KJD (n=20) or TKA (n=40). In the second arm, earlier-stage patients with medial compartment OA and a varus angle <10° were randomized to KJD (n=23) or high tibial osteotomy (HTO; n=46). In the distraction patients, the knee was distracted 5 mm for 6 weeks using external fixators with built-in springs, placed laterally and medially, and weight-bearing was encouraged. WOMAC scores and VAS pain scores were assessed at baseline and at 3, 6, 12, 18, and 24 months.

At 24 months, researchers found no significant differences between the KJD and HTO groups in that part of the trial. In the KJD/TKA arm, there was no difference in WOMAC scores between the two groups, but VAS scores were lower in the TKA group. The improvement in mean joint space width seen at one year in the KJD group of the KJD/TKA arm decreased by two years, though the values were still improved compared to baseline. However, the joint space width improvement seen at 1 year for both groups in the KJD/HTO arm persisted for two years. For all KJD patients, the ratio of biomarkers of synthesis over breakdown of collagen type-II was significantly decreased at 3 months but reversed to an increase between 9 and 24 months.

It is hard to believe that 6 weeks of joint distraction could trigger a process that yields such positive and long-lasting results. While much more research with longer follow-up is needed, KJD may prove particularly useful in younger knee OA patients trying to delay joint replacement.

References

  1. van der Woude, JAD, Wiegant, K, van Roermund, PM, Intema, F, Custers, RJH, Eckstein, F. Five-year follow-up of knee joint distraction: clinical benefit and cartilaginous tissue repair in an open uncontrolled prospective study. Cartilage. 2017;8:263-71.
  2. Jansen MP, Besselink NJ, van Heerwaarden RJ, Roel J.H. Custers1, Jan-Ton A.D. Van der Woude J-TAD, Wiegant K, Spruijt S, Emans PJ, van Roermund PM, Mastbergen SC, Lafeber FP. Knee joint distraction compared with high tibial osteotomy and total knee arthroplasty: two-year clinical, structural, and biomarker outcomes. ORS 2019 Annual Meeting Paper No. 0026 (Cartilage. 2019 Feb 13:1947603519828432. doi: 10.1177/1947603519828432. [Epub ahead of print])