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With OCA, Don’t Fret About Condyle Matching

OCA for OBuzz

Osteochondral allograft transplantations (OCAs) are becoming a mainstay of treatment for knee-cartilage injuries. To help ensure that the allograft plug is transplanted with <1 mm of step-off from the surrounding recipient cartilage, many surgeons restrict themselves to orthotopic OCAs—matching the graft-recipient condyles in a lateral-to-lateral or medial-to-medial fashion.

However, in the October 4, 2017 issue of The Journal of Bone & Joint Surgery, Wang et al. demonstrated that both orthotopic and non-orthotopic (e.g., lateral condyle-to-medial condyle) OCA resulted in significantly improved outcomes in 77 cases followed for a mean of 4.3 years. The authors found that reoperation rates and pre- and postoperative scores in physical functioning and pain did not differ significantly between the orthotopic (n=50) and non-orthotopic (n=27) groups. These results suggest that condyle-specific matching may not be necessary.

One problem with orthotopic OCA is that 75% of the available allograft is supplied in the form of lateral condyles, while most full-thickness cartilage lesions presenting for treatment occur in the medial condyle. Consequently, surgeon preferences for orthotopic OCA limit the number of available matches and lead to an estimated 13% of available grafts being discarded.

Noting that many factors contribute to successful resurfacing of cartilage defects in the knee, the authors say that “it may be overly simplistic to assume that a conventionally matched orthotopic allograft will ensure a smooth surface contour at the recipient site.” They go on to conclude that “if surgeons forewent condyle-specific matching, more allografts would be readily available, which would shorten wait times, provide fresher grafts with increased chondrocyte viability, and lower procedure costs.”

New Level-I Data on TKA Blood Conservation

TXAMinimizing perioperative blood loss during total knee arthroplasty (TKA) helps curtail the risks and costs of allogeneic blood transfusions. Currently, the most popular pharmacological approach to blood conservation is the antifibrinolytic agent tranexamic acid (TXA). But in a randomized trial published in the October 4, 2017 edition of The Journal of Bone & Joint Surgery, Boese et al. found that a similar and much less expensive compound, epsilon-aminocaproic acid (EACA), performed almost as effectively and just as safely as TXA in patients undergoing unilateral knee replacement.

Although the 98 patients in the study who received TXA averaged less estimated blood loss than the 96 patients who received EACA, no transfusions were required in either group, and there were no statistically significant or clinically relevant between-group differences in the change in hemoglobin levels. On the safety/complication side, there were no statistically significant between-group differences in any measured parameter, including postoperative serum creatinine levels or renal, bleeding, or thrombotic complications. However, there were 3 pulmonary emboli in the EACA group compared with only 1 in the TXA group. While that was not a statistically significant difference, “an observed difference of this magnitude could limit the usefulness of EACA in TKA,” the authors caution.

This study did not compare the current cost of the two compounds, but back in 2012, when the authors’ institution added antifibrinolytics to their blood management program, TXA cost $43/g, compared with $0.20/g for EACA. The cost differential is striking, even when you consider that TXA is at least 7 times more potent than EACA on a molar basis, so less of the former drug is required.

Boese et al. conclude that “TXA does not have superior blood conservation effects or safety profile compared with EACA in TKA,” but they cite a need for future equivalence, superiority, and noninferiority trials with these drugs.

D-Dimer Levels May Help with PJI Diagnoses

D-dimer for OBuzzThe percentage of periprosthetic joint infections (PJIs) among patients requiring revision arthroplasty of the hip and knee is increasing. PJIs have important clinical implications both for revision surgical procedures as well as pre- and postoperative management. Any extra help we can get making a PJI diagnosis outside of the obvious (where the patient presents with a draining wound) would be most welcome.

In the September 6, 2017 issue of The Journal, Shahi et al. present compelling data from a prospective study suggesting that serum D-dimer levels may help diagnose PJI—and thereby help determine the optimal timing of component reimplantation. The authors determined that 850 ng/mL was the optimal threshold value for D-dimer in diagnosing PJI. Moreover, with sensitivity of 89% and specificity of 93%, this test outperformed the widely used ESR and CRP tests, which until now have proven to be the “best” tools we have at our disposal.

Ideally, after these results are confirmed in larger populations of patients undergoing revision arthroplasty, the serum D-dimer test—inexpensive and almost universally available—will be used in all high-volume joint replacement centers. The continued pursuit of diagnostic and treatment methodologies for patients with suspected PJI is definitely warranted, given the increasing number of patients requiring arthroplasty and combined lifetime knee- and hip-replacement revision rates hovering around 10% to 12%. The identification of D-Dimer elevation as a potentially more accurate diagnostic tool than our currently available tests is a welcome contribution.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Longer Surgeries, Lengths of Stay Associated with More Adverse Events

Trauma Image for OBuzzThe phrase “adverse event” has been defined variably in the orthopaedic literature, which is one reason identifying the factors associated with such events can be tricky. In the August 16, 2017 edition of The Journal of Bone & Joint Surgery, Millstone et al. go a long way toward pinpointing modifiable factors that boost the risk of adverse events.

Using an institution-wide adverse-event reporting system called OrthoSAVES, the authors analyzed adverse events among 2,146 patients who underwent one of three elective orthopaedic procedures: knee replacement, hip replacement, or spinal fusion. They found an overall adverse event rate of 27%, broken down by surgical site as follows:

  • 29% for spine
  • 27% for knee
  • 25% for hip

The most common adverse events had a low severity grade (1 or 2); the authors suggest that including events typically not viewed as severe (such as urinary retention) is one reason the overall adverse event rate in this study was higher than most previously reported.

The unique finding from this study was that two modifiable factors—length of stay and increasing operative duration—were independently associated with a greater risk of an adverse event. More specifically, the authors found that, regardless of surgical site, each additional 30 minutes of surgery increased the adjusted odds for an adverse event by 13%.

The authors were quick to point out that their findings should not be interpreted as an admonition for surgeons to hurry up. “While operative duration may be a modifiable factor, operating more quickly for spinal or any other procedures may, itself, lead to increased complications,” they wrote. Rather, Millstone et al. suggest that the multiple factors comprising “procedural efficiency” during a surgical hospitalization warrant further investigation.

For TKA Pain Relief, Motor-Sparing Blocks Last Longer than Periarticular Infiltration

Adductor Canal Block for OBuzz
Analgesia after total knee arthroplasty (TKA) is a multimodal affair these days. Main goals include maintaining adequate patient comfort while limiting opiate use and permitting early mobilization.

In the August 2, 2017 issue of JBJS, Sogbein et al. report on a blinded randomized study comparing the performance of two types of analgesia often used in multimodal TKA pain-management protocols: preoperative motor-sparing knee blocks and intraoperative periarticular infiltrations.

Prior to surgery, the 35 patients in the motor-sparing block group received a midthigh adductor canal block under ultrasound guidance, combined with posterior pericapsular and lateral femoral cutaneous injections. The 35 patients in the periarticular infiltration group received study-labeled local anesthetics intraoperatively, just prior to component implantation.

Defining the “end of analgesia” as the point at which patient-reported pain at rest or activity rated ≥6 on the numerical rating scale and rescue analgesia was administered, the authors found that the duration of analgesia was significantly longer for the motor-sparing-block group compared with the periarticular-infiltration group. The infiltration group had significantly higher scores for pain at rest for the first 2 postoperative hours and for pain with knee movement at 2 and 4 hours. There were no between-group differences in time to mobilization, length of hospital stay, opiate consumption, or functional recovery.

August 2017 Article Exchange with JOSPT

JOSPT_Article_Exchange_LogoIn 2015, JBJS launched an “article exchange” collaboration with the Journal of Orthopaedic & Sports Physical Therapy (JOSPT) to support multidisciplinary integration, continuity of care, and excellent patient outcomes in orthopaedics and sports medicine.

During the month of August 2017, JBJS and OrthoBuzz readers will have open access to the JOSPT article titled “Clinical Prediction Models for Patients With Nontraumatic Knee Pain in Primary Care: A Systematic Review and Internal Validation Study.”

This systematic review yielded two new prognostic models for function and recovery in patients with nontraumatic knee pain. A longer duration of complaints predicted poorer function.

Let Unstable Chondral Lesions Be During Partial Meniscectomy

Chondral Debridement Graph for OBuzzMore than 900,000 patients every year undergo knee arthroscopy in the US. Many of those procedures involve a partial meniscectomy to address symptomatic meniscal tears. Surgeons “scoping” knees under these circumstances often encounter a chondral lesion—and most proceed to debride it.

However, in the July 5, 2017 issue of JBJS, Bisson et al. report on a randomized controlled trial that suggests there is no benefit to arthroscopic debridement of most unstable chondral lesions when they are encountered during partial meniscectomy. With about 100 patients ≥30 years old in each group, the authors found no significant differences in function and pain outcomes between the debridement and observation groups at the 1-year follow-up. In fact, relative to the debridement group, the observation group had more improvement in WOMAC and KOOS pain scores at 6 weeks, better SF-36 physical function scores at 3 months, and increased quadriceps circumference at 6 months.

The authors conclude that these findings “challenge the current standards” of typically debriding chondral lesions in the setting of arthroscopic partial meniscectomy. They also surmise that, in conjunction with declining Medicare reimbursements for meniscectomies with chondral debridement, these results “may lead to a reduction in the rate of arthroscopic debridement.”

Remove or Retain the PCL in TKA?

Posterior Stabilized Knee for OBuzz.jpegIn the world of total knee arthroplasty (TKA), the arguments about retaining the posterior cruciate ligament (PCL) versus stabilizing the knee with posterior-stabilized components have raged for more than 30 years. The number of cohort studies and controlled trials attempting to clarify the issue have been too high to count. In the July 5, 2017 issue of The Journal, Vertullo et al. use the power of the Australian national joint registry to add additional important clinical information to the debate.

More than 62,000 TKA cases formed the substrate of this analysis. In a study-design twist, the revision-related outcomes were analyzed on the basis of the preference surgeons had for the two different design options, not on the basis of which prostheses were actually used. Consequently, there was a likelihood that the cohort of patients treated by surgeons who had a preference for posterior-stabilized designs would include some PCL-retained cases, and vice-versa. The authors claim that this “instrumental variable analysis” has “the capacity to remove the confounding by indication or disease severity against posterior-stabilized total knee replacements.” However, as with any registry study, there were still many confounding variables that could have influenced the revision rate, not the least of which is surgeon skill in component alignment and ligament tensioning.

Nevertheless, with selection bias minimized, Vertullo et al. found a real difference in revision rates favoring retention of the PCL. That finding does make biomechanical sense to this non-arthroplasty surgeon, who would expect less stress on the tibial component-bone interface at the extremes of knee motion with the PCL-retaining procedure.

Biomechanics notwithstanding, I think this very large registry-based arthroplasty study will influence the debate going forward, but I doubt it will end the debate or that it will change the TKA practices of many surgeons worldwide. For a more definitive and potentially practice-changing resolution to this clinical conundrum, we’ll need a very large (2,000 to 3,000 patients in each arm) international trial where surgeons and patients accept randomization between these two choices.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

Chondroitin Sulfate Similar to Celecoxib in Easing Pain of Knee OA

Rich Yoon Headshot.jpgOrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Richard Yoon, MD, in response to a recent study in Annals of the Rheumatic Diseases.

European investigators recently reported on a trial comparing the efficacy of pharmaceutical-grade chondroitin sulfate (CS) (800 mg/day) with the NSAID celecoxib (CX) (200 mg/day) and placebo in more than 600 patients with painful knee osteoarthritis (OA).

In this well-designed, well-executed, double-blinded, 3-armed trial, investigators tracked patient pain scores at baseline and at 1-month, 3-month and 6-month intervals. This trial was characterized by strict adherence to blinded protocols, high levels of patient adherence, and meticulous review of patient diaries and adverse-event reports.

Patients in both the CS and CX groups experienced significantly greater pain relief when compared to those in the placebo group at every follow-up time point. In addition to tracking pain via the visual analogue scale (VAS), the investigators included the Lequesene index (LI)—which integrates both pain and function—along with the Minimal-Clinically Important Improvement (MCII) scale. While CX and CS were not superior/inferior to one another, both active treatments provided significant pain improvements relative to placebo according to all three measurements at all time points.

These findings showing the efficacy of pharmaceutical-grade CS are important for orthopaedic surgeons, rheumatologists, and general practitioners. Nonoperative management of knee OA remains an important modality that requires a multimodal approach, typically including NSAIDs and/or acetaminophen. These results suggest that there’s another safe medication that may prove especially helpful for OA patients who cannot tolerate NSAIDs or acetaminophen due to kidney, gastrointestinal, cardiovascular, and/or liver issues.

Richard Yoon, MD is a fellow in orthopaedic traumatology and complex adult reconstruction at Orlando Regional Medical Center.

Can Only 4 Questions Yield Meaningful Patient Outcome Measures?

Guy and Computer for PROMIS O'Buzz.jpgIn today’s data-driven, evidence-based world of orthopaedics, capturing accurate information about a patient’s physical function can require patients to answer dozens of separate questions. In the June 7, 2017 edition of JBJS, Hancock et al. investigate whether the computer-based tool called PROMIS (Patient-Reported Outcomes Measurement Information System) PF CAT is more efficient than and just as reliable as the more burdensome function-evaluation instruments.

In short, the answer is yes. Among a group of otherwise healthy patients scheduled to undergo meniscal surgery, the PROMIS PF CAT scores were generally highly correlated with traditional patient-reported physical-function measures, such as the SF-36 Physical Function instrument and the KOOS Sport and Quality-of-Life scores.

In contrast to the more traditional fixed-length questionnaires, the PROMIS PF CAT presents an initial item to the patient, and uses the response to that to select the most informative next item. That process continues only until a predefined level of precision is reached, at which point the test ends. The vast majority (89%) of the patients in this study completed the PROMIS PF CAT after answering only four items.

Considering its strong correlation with other widely accepted measurement tools and its efficiency, the authors conclude that PROMIS PF CAT “may be a good alternative for evaluating physical function in meniscal injury populations,” and that it could help “reduce burnout and maintain high response rates” in a time-constrained health care environment.