Archive | September 2018

Primary TJA Volume Growth from 2014 to 2030: Not So Fast?

TJA Volume for OBuzzAnnual volume projections for total joint arthroplasty (TJA) have been cited frequently and applied broadly, often to estimate future costs. But with a slowdown in the growth of the annual incidence of total knee arthroplasty (TKA), updated projections are needed, and that’s what Sloan et al. provide in the September 5, 2018 issue of JBJS.

Using the National Inpatient Sample to obtain TJA incidence data, the authors first analyzed the volume of primary TJA procedures performed from 2000 to 2014. They then performed regression analyses to project future volumes of TJA procedures. Here are the numbers based on the 2000-to-2014 data:

  • Primary total hip arthroplasty (THA) is projected to grow 71%, to 635,000 annual procedures by 2030.
  • Primary TKA is projected to grow 85%, to 1.26 million annual procedures by 2030.

However, the TKA procedure growth rate has slowed in recent years, and models based on 2008-to-2014 data project growth to only 935,000 annual TKAs by 2030—325,000 fewer procedures relative to the 2000-to-2014 models.

Earlier studies, notably one by Kurtz et al. in 2007, obviously could not account for the reduced growth rate in TKA after 2008. A 2008 analysis by Wilson et al., based on the Kurtz et al. data, estimated that annual Medicare expenditures on TJA procedures would climb  from $5 billion in 2006 to $50 billion in 2030. “Using our projections,” say Sloan et al., “we predict that Medicare expenditures on these procedures in 2030 will be less than half of that predicted by Wilson et al.”

These findings lend credence to the authors’ observation that “it is imperative that projections of orthopaedic procedures be regularly evaluated and updated to reflect current rates.”

Use Data, Guidelines, and Intuition to Manage Infection after Toe/Forefoot Amputation

Osteomyelitis for OBuzzThe number of articles published each year in orthopaedics that evaluate infections seems to approach, if not exceed, 1,000. Yet, despite all of these publications, consensus statements, and guidelines, we seem to have very few concrete recommendations about which every surgeon will say, “This is what needs to be done.” So we send out samples, run cultures, sonicate implants, and sometimes even perform DNA sequencing, and then we mix the data with selected recommendations and intuition to make our final treatment decisions. Foolproof? No, but it is the best we can do in many situations.

The article by Mijuskovic et al. in the September 5, 2018 edition of The Journal helps simplify this type of decision making in the setting of residual osteomyelitis after toe or forefoot amputation. The authors evaluated 51 consecutive patients with gangrene and/or infection who underwent either digit or partial foot amputations. They found that, after surgery, 41% of the patients without histological evidence of osteomyelitis (which the authors considered the reference, “true positive” analysis) had a positive culture from the same sample.  In addition, only 12 patients (24%) had both positive histological findings and positive cultures, the criteria set forth by the Infectious Disease Society of America for the definitive diagnosis of osteomyelitis.

As interesting as the main findings of the study are, some of the “minor” results are even more curious.  The decision regarding which patients received antibiotics after amputation seemed largely arbitrary, with 10 of the 14 patients who had a positive histological result not receiving any postoperative antibiotics. (Five of those patients ended up needing a secondary procedure.) In addition, because of the need for decalcification prior to analysis, the median time to receiving histological results was almost a week. Based on the findings in this study, in many instances patients are sent home or to a rehabilitation facility with antibiotics based only on the results of a potentially “false-positive” culture.

The authors conclude that their results “cast doubt on the strategy of relying solely on culture of bone biopsy specimens when deciding whether antibiotic treatment for osteomyelitis is necessary after toe or forefoot amputation.” But this paper also highlights the fact that we are still looking for definitive answers about which data to use and which to disregard when it comes to the detection and treatment of post-amputation osteomyelitis. We surgeons decide on which side to err, and we need to appreciate all three facets—data, guidelines, and patient factors—when discussing treatment options with patients.

Chad A. Krueger, MD
JBJS Deputy Editor for Social Media

Helpful Hint for Managing Femoral Neck Stress Fractures

Hip Effusion for OBuzzThe incidence of patients presenting with proximal thigh and groin pain is increasing along with increased interest in recreational athletic activity. When it is associated with a history of increased physical activity, this pain profile often prompts the ordering of a hip MRI if presenting radiographs are unremarkable. However, surgeons often find it difficult to make accurate prognoses and treatment recommendations when the MRI findings suggest a femoral neck stress fracture.

In the September 5, 2018 issue of The Journal, Steele et al. provide us with helpful hints for determining when to proceed with surgical stabilization of the femoral neck in this clinical scenario. Of the femoral neck stress fracture patients in this study who progressed to a surgical procedure, >85% had an effusion on the initial MRI, compared with only 26% of those whose condition resolved with nonoperative treatment. In statistical terms, those who had a hip effusion had an 8-fold increased risk of progression to surgery compared to those without a hip effusion. Meanwhile, the overall fracture-line percentage on the initial MRI turned out to be a poor metric for predicting progression.

Stabilization of a femoral neck stress fracture with percutaneous implants usually improves pain and predictably prevents displacement of the fracture and the attendant risk of nonunion and osteonecrosis of the femoral head. Further clinical research should help validate the seemingly reliable MRI-based predictor identified by these authors.

Marc Swiontkowski, MD
JBJS Editor-in-Chief