Failure Factors after 1-Stage Exchange TKA

Prior to performing a primary total joint arthroplasty, patient optimization is both possible and recommended. However, when a patient with a periprosthetic joint infection (PJI) comes in to your office, opportunities for patient optimization are limited. At that point, the patient’s BMI, kidney/liver values, and HgbA1c/fructosamine levels are not going to be dramatically improved prior to any procedure to eradicate the infection and/or salvage the implant. Still, for the purposes of care optimization and prognostic guidance, it is important to identify specific patient or wound characteristics that may help us flag patients who are at increased risk for failure after treatment of a PJI.

That was the goal of the case-control study by Citak et al. in the June 19, 2019 edition of The Journal. The authors compared 91 patients who experienced a failed 1-stage revision total knee arthroplasty that was performed to treat a PJI to a matched cohort who had a successful 1-stage revision to treat a PJI. (The authors defined “failure” as any subsequent surgical procedure regardless of reason.)

A bivariate logistic analysis revealed that patients who had a history of a previous 1-stage (OR 29.3; p< 0.001) or 2-stage (OR 5.8; p <0.001) exchange due to PJI, or who had Streptococcus (OR 6.0; p = 0.013) or Enterococcus (OR 17.3; p = 0.023) isolated from their wound were at increased risk of reinfection compared to the control group. Just as important, the authors found that patient body weight of 100 kg or above and history of deep vein thrombosis (DVT) were the only patient comorbidities related to an increased risk of a failed revision.

While these findings may not be surprising in light of previous data on this topic, they are important in aggregate. Patients whose wounds contain isolated enterococci or streptococci may not be ideal candidates for 1-stage PJI revision surgery. Additionally, the authors highlight that patients who have failed two or more attempts at a 1-stage revision should be considered for a 2-stage protocol.

While many of the patients in this study who failed the 1-stage revision may have also failed a 2-stage revision, ongoing research comparing the two protocols should help further clarify whether certain infections are more amenable to successful treatment with one protocol or the other. In the meantime, studies such as this add valuable data that surgeons can use to guide patient care and provide meaningful patient education for shared decision-making about how to treat these difficult infections.

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

What’s New in Spine Surgery 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, Jacob M. Buchowski, MD, MS, coauthor of the June 19, 2019 What’s New in Spine Surgery,” selected the five most clinically compelling findings from among the 47 noteworthy studies summarized in the article.

Predictive Analytics for Deformity Conditions
–A validated model for predicting outcomes after lumbar spine surgery1 found that patients with lower preoperative disability scores, those covered by Medicaid or Workers’ Compensation, and current and previous smokers were less likely to improve with lumbar fusion surgery. Invasiveness of surgery and surgeon and hospital type had lower predictive value.

Early-Onset Scoliosis (EOS)
–A 5-year direct-cost estimate2 comparing magnetic growing rods and conventional growing rods for the treatment of EOS found the total cost for magnetic growing rods to be £34,741 compared with £52,293 for conventional growing rods.

Pediatric Neuromuscular Scoliosis
–A Level-II study investigated patient factors associated with postoperative pulmonary complications among patients with neuromuscular scoliosis who underwent posterior spinal fusion.3 Patients with a history of pneumonia or gastrotomy tube at the time of surgery had an elevated risk of postoperative respiratory infections.

Opioid Consumption
–Findings from a retrospective study of >27,000 patients who underwent lumbar decompression with or without fusion revealed that the majority of patients using prescription opioids discontinued those medications postoperatively. However, among the patients with opioid use >90 days after surgery, the duration of preoperative opioid use was the most important predictor of postoperative opioid use.

Neurological Decline after Adult Spinal Deformity Surgery
–In a retrospective analysis of 265 patients who underwent corrective surgery for adult spinal deformity,4 23% of patients experienced a neurological injury; among those, 33% experienced a major neurological decline. Among the patients with major decline, full recovery was observed in 24% at 6 weeks and 65% at 6 months, but one-third of those patients experienced persistent neurological deficits at 24 months postoperatively. Among patients who experienced a minor neurological injury, 49% reported full recovery at 6 weeks and 70% reported full recovery at 6 months. About one-quarter of those patients showed no improvement at 24 months.

References

  1. Khor S, Lavallee D, Cizik AM, Bellabarba C, Chapman JR, Howe CR, Lu D, Mohit AA, Oskouian RJ, Roh JR, Shonnard N,Dagal A, Flum DR. Development and validation of a prediction model for pain and functional outcomes after lumbar spine surgery. JAMA Surg.2018 Jul 1;153(7):634-42.
  2. Harshavardhana NS, Noordeen MHH, Dormans JP. Cost analysis of magnet-driven growing rods for early-onset scoliosis at 5 years. Spine (Phila Pa 1976).2019 Jan 1;44(1):60-7.
  3. Luhmann SJ, Furdock R. Preoperative variables associated with respiratory complications after pediatric neuromuscular spine deformity surgery. Spine Deform.2019 Jan;7(1):107-11.
  4. Kato S, Fehlings MG, Lewis SJ, Lenke LG, Shaffrey CI, Cheung KMC, Carreon LY, Dekutoski MB, Schwab FJ, Boachie-Adjei O, Kebaish KM, Ames CP, Qiu Y, Matsuyama Y, Dahl BT, Mehdian H, Pellisé F, Berven SH. An analysis of the incidence and outcomes of major versus minor neurological decline after complex adult spinal deformity surgery: a subanalysis of Scoli-RISK-1 study. Spine (Phila Pa 1976).2018 Jul 1;43(13):905-12.

Why Are Some Patients Unhappy after “Successful” Repair of Shoulder Instability?

It has been estimated that 13% to 16% of patients who undergo arthroscopic stabilization procedures for recurrent shoulder instability are dissatisfied with their outcome, despite a technically “successful” operation. Similarly high rates of patient dissatisfaction in the face of an objectively “well-done” surgery are pervasive in most orthopaedic subspecialties and often leave both surgeon and patient frustrated and perplexed. Prior research has suggested that patient expectations, psychological characteristics, and socioeconomic factors play a major role in these cases of patient dissatisfaction. But identifying precise patient or injury factors that can alert surgeons as to which patients may be unsatisfied after their procedure has remained elusive for many common injuries.

In the June 19, 2019 issue of The Journal, Park et al. examine the bases for patient dissatisfaction after arthroscopic Bankart repair (with or without remplissage) for recurrent shoulder instability. Not surprisingly, patient age, size of the glenoid bone defect, and the number of patient postoperative instability events correlated with an objective failure of the operation (i.e., instability requiring a repeat operation). However, the study found that the number of instability events and the preoperative width of the Hill-Sachs lesion correlated with the subjective failure of the operation (i.e., the patient was dissatisfied based on response to a single question about “overall function” 2 years after surgery). For the 14 out of 180 patients who were dissatisfied despite not experiencing a revision, intermittent pain plus psychological characteristics such as apprehension and anxiety about recurrent instability were common reasons for dissatisfaction.

It is becoming clearer with each passing year that simply correcting anatomic pathologies does not always result in happy patients. Orthopaedic surgeons need to employ patient interviewing techniques to identify issues such as anxiety, depression, pain-perception concerns, and substance abuse—all of which can negatively influence the degree of patient satisfaction with the result and are somewhat modifiable preoperatively.

Marc Swiontkowski, MD
JBJS Editor-in-Chief

June 2019 Article Exchange with JOSPT

In 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 June 2019, JBJS and OrthoBuzz readers will have open access to the JOSPT article titled “Hybrid Approach to Treatment Tailoring for Low Back Pain: A Proposed Model of Care.”

The authors of this clinical commentary propose a hybrid, prognosis-based approach to low back pain management that includes psychologically informed treatments for those with medium risk and a predominantly central pain mechanism and motor-control approaches to exercise for individuals with medium risk and a nociceptive pain mechanism.

Sarcopenia’s Role in Knee OA Progression

OrthoBuzz occasionally receives posts from guest bloggers. This guest post comes from Jeffrey Stambough, MD, in response to a recent study in Arthritis & Rheumatology.

The incidence of total knee arthroplasty to treat end-stage knee osteoarthritis (OA) continues to rise even in the face of patient risk-stratification tools and alternative payment models. Consequently, payers, patients, and their doctors are placing a premium on methods to prolong the native knee joint and delay or avoid surgery. This partly explains the explosion of interest in biologics and the subsequent checkreins being put in place regarding their use.

As the AAOS clinical practice guidelines for the management of knee arthritis clearly state, the best management for symptoms of knee arthritis remains weight loss and self-directed physical activity. However, there is uncertainty regarding which subtypes of patients are likely to achieve OA symptom benefits with different weight-loss strategies.

A recent large, multicenter cohort study published in Arthritis & Rheumatology attempted to further characterize patient body composition and its association with knee OA.  Using whole-body dual x-ray absorptiometry (DXA) measures of fat and muscle mass, researchers classified patients into one of four categories: nonobese nonsarcopenic, sarcopenenic nonobese, nonsarcopenic obese, or sarcopenic obese. Sarcopenia is the general loss of muscle mass associated with aging. If orthopaedic surgeons better understand how fat and muscle metabolism change with time and affect inflammation and chronic disease, they may be able to provide patients with additional insight into preventive measures.

Using DXA-derived calculations, the authors observed that among older adults, the relative risk of developing clinically significant knee osteoarthritis (Kellgren-Lawrence grade ≥2) at 5 years was about 2 times greater in both sarcopenic and nonsarcopenic obese male and female patients compared to nonobese, nonsarcopenic patients.  Sarcopenia alone was not associated with risk of knee OA in women or men. In a sensitivity analysis focusing on BMI, men showed a 3-fold greater risk of knee OA if they were sarcopenic and obese, relative to nonobese nonsarcopenic patients.

The takeaway from this study is that focusing solely on fat/weight loss may overlook a valuable opportunity to slow the progression of knee arthritis in some patients.  Further studies are needed to validate the contribution of low muscle mass to the development and progression of symptomatic knee arthritis.

Read this related OrthoBuzz post about sarcopenia’s relationship to mortality in elderly patients with acetabular fractures.

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.

Subacromial Balloon May Benefit Irreparable Cuff Tears

The surgical options for treating irreparable tears of the supraspinatus—cuff reconstruction, tendon transfers, and shoulder replacement—are limited and complicated. But biomechanical results from a cadaveric study of 14 shoulders by Lobao et al., published in the June 5, 2019 issue of JBJS, suggest that a biodegradable balloon spacer inserted subacromially could effectively treat such insufficiencies, possibly postponing the need for more aggressive procedures.

Using an irreparable supraspinatus tear model and sophisticated instruments, the authors determined that, at postoperative time 0, the saline-inflated balloon:

  • Restored intact-state glenohumeral contact pressures at most abduction angles
  • Moved the humeral head inferiorly by a mean of 6.2 mm at 0° of abduction and 3.0 mm at 60°
  • Increased deltoid load by 8.2% at 0° and by 11.1% at 60°.

The balloon, however, did not restore glenohumeral contact area to that of an intact shoulder.

Although the authors cite a previous clinical case series using this approach,1 they are quick to point out that “it is not possible to correlate our findings with clinical scenarios.” Nevertheless, they say that the biomechanical data obtained from this cadaveric study “suggest that the balloon may be of benefit clinically, at least in the immediate postoperative setting.”

Reference

  1. Deranlot J, Herisson O, Nourissat G, Zbili D, Werthel JD, Vigan M, Bruchou F. Arthroscopic subacromial spacer implantation in patients with massive irreparable rotator cuff tears: clinical and radiographic results of 39 retrospectives cases. Arthroscopy. 2017 Sep;33(9):1639-44. Epub 2017 Jun 8

Diagnosing Infection in “Dry” Prosthetic Joints

Despite a bevy of research and intense clinical focus, definitively diagnosing periprosthetic joint infections (PJIs) remains a major challenge in many patients. There is no single test that can confirm a PJI diagnosis with absolute accuracy, and surgeons often encounter clinical factors that make the diagnostic challenge even more complex. One such scenario is when a surgeon cannot aspirate enough fluid for culture from the affected joint of a patient who may have a PJI. In such situations, important microbiological data that would come from culturing synovial fluid are unavailable, leaving treating surgeons information-poor.

In the June 5, 2019 issue of The Journal, Li et al. provide surgeons with data about a controversial solution to this so-called “dry-tap” problem. The lead author performed aspirations on nearly 300 joints that were suspicious for periprosthetic infection. Eighty-two of those aspirations (29%) yielded ≤1.0 mL of synovial fluid. In those “dry-tap” cases, 10 mL of saline solution was injected into the joint, which was then reaspirated.

When comparing cultures from the aspirates that were the result of a saline lavage to those in which no lavage was performed, the authors found overlapping 95% confidence intervals in sensitivity, specificity, positive predictive value (PPV), and negative predictive value. However, the specificity (0.991 vs 0.857) and PPV (0.987 vs 0.889) were higher in the nonlavage cohort, even if those differences did not reach statistical significance. In addition, no significant differences were found between the groups in terms of relative frequencies of specific pathogen types.

Although the authors conclude that this lavage-and-reaspiration technique “is not necessarily inappropriate,” it is important to note that no post-hoc power analysis was performed, and therefore type II error needs to be considered because the study was probably underpowered. In addition, the International Consensus Meeting (ICM) recommends against lavaging a “dry” joint to obtain fluid for culture, largely because the injected saline will dilute results if a leukocyte esterase strip test or cell count is subsequently performed as part of the PJI-diagnosis process. Still, the authors point out that the data supporting the ICM’s recommendations against this practice are relatively weak, and the specificity and sensitivity data from this study are quite satisfactory.

So does this give us another option for determining whether a periprosthetic joint infection is present in patients from whom little or no synovial fluid can be obtained? Maybe. But this technique requires further investigation before it becomes widely implemented in practice. Without validation, it risks becoming just one more variable that could reinforce our own confirmation biases in these challenging cases. With further validation, however, it could allow pre-revision collection of valuable and accurate culture information from “dry” joints.

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

Marian Frauenthal Sloane, MD: Ahead of Her Time

In 2016, only 6.5% of practicing orthopaedic surgeons in the US were women. By contrast, 49% of all medical students in the US are women. That apparent discrepancy has sparked concern, conversations, and action in the orthopaedic community.

The current gender imbalance in orthopaedics would be even more stark were it not for two trailblazing women who lived during the early part of the 20th century. One of them, Ruth  Jackson, MD, is the well-known namesake of today’s professional society of female orthopaedic surgeons. The other, New York City orthopaedist Marian Frauenthal Sloane, MD, has endured relative obscurity, until now.

The “What’s Important” essay by Hooper at al. in the June 5, 2019 issue of The Journal of Bone & Joint Surgery profiles Dr. Frauenthal Sloane’s short but influential career as orthopaedic surgeon, researcher, author (she coauthored 2 JBJS articles in the 1930s), and teacher. Despite the long way we still have to go to achieve gender diversity in orthopaedics, the authors of this fascinating sketch conclude by saying that “without [Dr. Frauenthal Sloane’s] brief but profound influence, women orthopaedists would probably be in a very different place today.”

Read related OrthoBuzz post about diversity in orthopaedic surgery.

New Minute-Commentary Video

See what JBJS Deputy Editor for Social Media Chad Krueger, MD thinks about the just-published Level-I trial comparing nonoperative treatment to volar locking plate fixation among 140 elderly patients with dorsally displaced distal radial fractures.

Pelvic Fracture Classification Will Benefit Elderly Patients

The orthopaedic community began to move away from individual fracture classifications in the mid-1980s. The basis for that shift was the need for wider recognition that fractures represent a “continuous variable,” with infinite varieties of orientations and combinations of fracture lines. Trying to fit fractures into a narrow classification system can lead to confusion and misinformation. Furthermore, surgeons often disagree when determining a fracture’s classification and, therefore, which treatment is best.

To move away from individual classification systems, orthopaedic journals have generally moved toward the compendium of fracture classifications approved by the OTA and AO. Still, there are times when a new fracture classification seems appropriate, and in the June 5, 2019 issue of The Journal, Pieroh et al. have provided us with an example that classifies fragility fractures of the pelvis (FFP). The 4-group FFP classification is based on fracture morphology with different degrees of instability and includes treatment recommendations.

The authors collected the CT scans of 60 patients from 6 different hospitals who were ≥60 years old and had sustained a pelvic fracture from low-energy trauma. These CT scans were shown to 6 experienced surgeons, 6 inexperienced surgeons, and 1 surgeon who had direct experience/training with the FFP system. Each surgeon was asked to classify the pelvic fractures according to the FFP classification. Inter- and intra-rater reliabilities for the fracture classifications were calculated from these readings, and the overall inter-rater Kappa coefficient was found to be 0.53, while the overall intra-rater Kappa coefficient was 0.46 (Kappa coefficients of 0.61 to 0.41 constitute “moderate” reliability). In terms of percent agreement, there was greater agreement between surgeons when it came to classifying FFP Group 1 fractures than for FFP Group 2 and 3 fractures. This is noteworthy because Group 3 fractures are thought to require surgical treatment, while primary treatment for Group 2 fractures is usually nonoperative.

Pelvic fractures that are associated with low bone density and low-energy trauma are becoming increasingly frequent as our population continues to skew older. Having a validated, relatively straightforward classification system like the FFP to assist us in managing these patients will be of great assistance. The sound methodology used to develop the FFP classification system and its decent reliability, face validity, and construct and criterion validity can assure all of us about the usefulness of the FFP classification as the basis for future clinical investigations and to advance the care of these patients.

Marc Swiontkowski, MD
JBJS Editor-in-Chief