Archive | June 2019

New Minute-Commentary Video

Here’s what JBJS Deputy Editor for Social Media Chad Krueger, MD concludes after reading a prospective cohort study from the Cleveland Clinic Orthopaedic Arthroplasty Group examining the main predictors of length of hospital stay after knee replacement:

Severe Congenital Scoliosis Lowers Exercise Capacity

The etiology and pathogenesis of adolescent idiopathic scoliosis (AIS) and congenital scoliosis are markedly different. Among the differences, progressive congenital scoliosis has the potential to cause much more severe impairment of pulmonary function than does AIS.

In an observational study in the June 19, 2019 issue of The Journal of Bone & Joint Surgery, Lin et al. investigate the precise extent to which pulmonary function and exercise capacity are affected by congenital scoliosis of varying severity. Sixty patients with congenital scoliosis (ranging from 10 to 39 years old) underwent spinal radiography, static pulmonary function testing (PFT), and dynamic cardiopulmonary exercise testing (CPET). From that data the researchers determined the impact of thoracic spinal deformity and rib anomalies on pulmonary function and exercise capacity.

Not surprisingly, PFT results, including total lung capacity, decreased as the severity of thoracic curves increased. In addition, patients with moderate or severe static pulmonary dysfunction had lower exercise tolerance than those with no or mild pulmonary dysfunction. CPET also revealed reduced ventilation capacity, faster respiratory rate, and smaller tidal volume in patients with more complex rib anomalies, although overall exercise tolerance did not differ among patients based on the severity of rib anomalies.

The authors observe that “although patients with thoracic deformities have the potential to compensate during increasing exercise,…exercise capacity (represented by work rate and maximal heart rate) declined greatly in patients with a thoracic curve exceeding 100°.” Because of the connection between congenital scoliosis with pronounced thoracic curves and loss of exercise capacity, Lin et al. recommend “early diagnosis, close follow-up, and timely treatment” for patients with this condition.

Stemming the Tide of Stem Cell Hype

Stem Cells for OBuzzThis 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.

Despite the absence of research-based guidance, the use of stem cell therapies in musculoskeletal medicine has gained popularity and stimulated patient interest. Consequently, an international consensus was  recently established to develop strategies to improve standardization and transparency when describing cell therapies, and to develop a consensus on the contents of a standardized tool for describing cell therapies.1 The tool, dubbed DOSES, was an outgrowth of a call for improvement in communicating about cell-based therapies made during the American Academy of Orthopaedic Surgeons/National Institutes of Health Optimizing Clinical Use of Biologics Symposium in 2018.

The international experts used an iterative Delphi methodology to develop DOSES. The five components of the DOSES tool are Donor (i.e., autologous, allogeneic, xenogeneic), Origin of tissue (fat, bone marrow, etc.), Separation from other cell types/preparation method, Exhibited cell characteristics, and the Site of delivery. The tool should help clinicians, researchers, regulators, and industry professionals describe and communicate about any given stem cell treatment clearly and transparently.

In a commentary on the DOSES article, Scott Rodeo, MD notes that efforts are under way to clarify and classify stem cells by genomics, proteomics, metabolomics, and other approaches.2 Dr. Rodeo believes that the most important component of DOSES is the “E” category, information that will ultimately characterize the biologic activity of the cell preparation. He concludes by encouraging “clinicians, industry, and authors of both laboratory and clinical studies to begin the use of the DOSES tool, and possibly other algorithms, when communicating the results of cell therapy investigations.” This admonition carries over to journal editors, who, Dr. Rodeo says, should “consider adopting such reporting standards as mandatory for publication” of stem cell studies.

For stem cell therapy to progress clinically in the future, researchers and clinicians must apply a consistent nomenclature to describe cell therapies and actual cell formulations.3 This is lacking in today’s applications.

References

  1. Murray IR, Chahla J, Safran MR, Krych AJ, Saris DBF, Caplan AI, LaPrade RF. International Expert Consensus on a Cell Therapy Communication Tool: DOSES. J Bone Joint Surg Am. 2019 May 15;101(10):904-911. doi: 10.2106/JBJS.18.00915. PMID: 31094982
  2. Rodeo SA. A Call for Standardization in Cell Therapy Studies: Commentary on an article by Iain R. Murray, BMedSci(Hons), MRCS, MFSEM, PhD, et al.: “International Expert Consensus on a Cell Therapy Communication Tool: DOSES”. J Bone Joint Surg Am. 2019 May 15;101(10):e47. doi: 10.2106/JBJS.19.00189. PMID: 31094994.
  3. Jones IA, Chen X, Evseenko D, Vangsness CT Jr. Nomenclature Inconsistency and Selective Outcome Reporting Hinder Understanding of Stem Cell Therapy for the Knee. J Bone Joint Surg Am. 2019 Jan 16;101(2):186-195. doi: 10.2106/JBJS.17.01474. PMID: 30653050

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