Published 2/1/2018

Second Look – Clinical News and Views

These items originally appeared in AAOS Headline News Now, a thrice-weekly enewsletter that keeps AAOS members up to date on clinical, socioeconomic, and political issues, with links to more detailed information. Subscribe at www.aaos.org/news/news.asp (member login required).

Patient safety
OA prevalence—A study in the American Journal of Public Health (online) examining trends in arthritis finds that prevalence of osteoarthritis (OA) has more than doubled in the United States from 1999 to 2014. The researchers analyzed data on 43,706 community-dwelling adults aged 20 years and older who participated in the 1999–2014 National Health and Nutrition Examination Surveys. They found that the age-adjusted prevalence of arthritis was 24.7 percent. Overall prevalence of OA increased from 6.6 percent to 14.3 percent, while prevalence of rheumatoid arthritis decreased from 5.9 percent to 3.8 percent.

Ambulatory TJA—Data from a study in The Journal of Arthroplasty (January) suggest that patient selection is an important factor for maintaining patient safety for TJA performed in an ambulatory surgery center (ASC). The authors reviewed charts of 3,444 TJA patients and assigned ASC eligibility based on American Society of Anesthesiologists (ASA) status, exclusion criteria, and existing comorbidities. They found that 70.3 percent of all patients were eligible for TJA performed in an ASC. Among ASA III patients who did not meet any exclusion criteria but had systemic disease, the researchers deemed 53.69 percent ASC-eligible due to sufficiently low severity of comorbidities. The most frequent reasons for ineligibility were body mass index >40 kg/m 2, severity of comorbidities, and untreated obstructive sleep apnea.

Bone density—According to a study in The Journal of Bone and Mineral Research (online), the timing of puberty may affect areal bone mineral density (aBMD) in a skeletal site- and sex-specific manner that tracks throughout life. Members of the research team constructed sex-specific polygenic risk scores (GRS) of 333 genetic variants linked to later puberty in European-descent children participating in the Bone Mineral Density in Childhood Study. In a Mendelian randomization framework, they noted that the puberty-delaying GRS supported a causal association with lower lumber spine and femoral neck aBMD in adults of both sexes.

Cigarette smoking—Data published in Medicine & Science in Sports & Exercise (November) suggest that cigarette smoking may increase risk of musculoskeletal injury. The researchers conducted a meta-analysis of 18 studies that looked at musculoskeletal injuries and cigarette smoking among military populations. They found smoking to be a moderate risk factor for musculoskeletal injury. In addition, they note that although enlistees are not allowed to smoke during basic training, their risk of injury remains high, suggesting that smokers may remain at increased risk for some time after quitting.

Gadolinium-based contrast agents—The U.S. Food and Drug Administration (FDA) is requiring a new class warning and other safety measures for all gadolinium-based contrast agents (GBCAs) for magnetic resonance imaging. Published research has suggested evidence of a link between GBCAs and nephrogenic systemic fibrosis in kidney patients, and recent studies have found that patients without impaired renal function may also show deposits of gadolinium. The FDA issued a MedWatch safety alert regarding gadolinium retention on May 22, 2017. After additional review and consultation, the agency is requiring manufacturers of GBCAs to conduct human and animal studies to further assess the safety of the contrast agents. It is also requiring a new medication guide be made available to patients prior to receiving a GBCA.

Hip and knee
CoC vs. CoP bearings—Findings published in The Journal of Arthroplasty (online) suggest similar long-term survivorship and function for total hip arthroplasty (THA) patients treated with either ceramic on ceramic (CoC) or ceramic on polyethylene (CoP) bearings. The authors conducted a prospective study of 57 patients (58 hips) with a mean age of 42 years. At minimum 15-year follow-up, they found that three patients died, but had not been revised, and seven patients had been lost to follow-up. Among the remaining patients, they found that five cases from the CoP cohort were revised (four for polyethylene wear and osteolysis), while four from the CoC cohort were revised (one each for head fracture, instability, infection, and trunnionosis). Patients in both groups displayed similar statistically significant improvement in Harris Hip Score and St. Michael's Score.

Tourniquet vs. TXA—Data from a study conducted in China and published in The Journal of Bone & Joint Surgery (Dec. 20) suggest that tourniquet use may not be necessary when tranexamic acid (TXA) is available to reduce blood loss during primary total knee arthroplasty (TKA). The authors conducted a prospective, randomized, controlled trial of 150 patients who were treated with either tourniquet as well as multiple doses of intravenous TXA and one dose of topical TXA (n = 50), intravenous and topical TXA (n = 50), or tourniquet with no TXA (n = 50). They found that total intraoperative blood loss was similar across all cohorts. However, patients in the TXA-only group saw significantly less hidden blood loss, reduced postoperative swelling and levels of inflammatory biomarkers, and improved visual analog scale pain score, range of motion at discharge, Hospital for Special Surgery score, and patient satisfaction.

Patient demographics—According to a study in Arthritis Care & Research (online), higher patient education level may be associated with improved outcomes for TKA patients living in poorer communities. Members of the research team reviewed institutional registry and U.S. Census Bureau data on 3,970 TKA patients, 2,438 (61 percent) of whom reported having received at least some college education. They found that the lack of any college education was associated with worse Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function at baseline and 2-year follow-up, while living in a poor neighborhood (defined as >20 percent below poverty) was associated with worse WOMAC pain and function at 2 years. Furthermore, the researchers noted that patients without a college education living in poor communities had pain scores approximately 10 points worse than those with some college education; in wealthy communities, college education was associated with a difference in pain of only 1 point.

Fracture screening—Data from a study conducted in the United Kingdom and published in The Lancet (online) suggest that implementation of a community-based fracture risk screening program could help reduce incidence of hip fracture among older women. The authors conducted a randomized, controlled trial of 12,483 women aged 70 to 85 years, 6,233 of whom were randomly assigned to a screening program using the Fracture Risk Assessment Tool. They found that treatment was recommended for 898 (14 percent) of screened participants. At 1-year follow-up, use of osteoporosis medication was significantly higher in the screening group compared with those in the control group. The authors found that screening was not associated with a reduction in incidence of all osteoporosis-related fractures, nor the overall incidence of all clinical fractures. However, screening was associated with a reduction in incidence of hip fracture.

Shoulder and elbow
Patient demographics—A study conducted in Australia and Canada and published in the Journal of Shoulder and Elbow Surgery (online) attempts to identify normative patient-reported outcome measure (PROM) values for healthy patients. The researchers surveyed 653 individuals without dominant shoulder pathology for the American Shoulder and Elbow Surgeons shoulder score; Constant-Murley Shoulder Score; Oxford Shoulder Score; University of California, Los Angeles shoulder score; Shoulder Pain and Disability Index; and Stanmore Percentage of Normal Shoulder Assessment. They found that differences in sex, age, and geographical location may affect PROM shoulder scores in pathology-free individuals. The researchers recommend that demographic factors be taken into consideration when PROMs are used to compare patient outcomes.

Protein variation—A study conducted in China and published in Anesthesiology (online) suggests that genetic variation of brain-derived neurotrophic factor (BDNF) may be linked with an increased risk of chronic postsurgical pain. Members of the research team genotyped 638 polymorphisms within 54 pain-related genes across 1,152 surgical patients enrolled in the Persistent Pain after Surgery Study. At 12-month follow-up, they found that 21.4 percent (n = 246) of patients reported chronic postsurgical pain. Overall, 42 polymorphisms were associated with chronic postsurgical pain—19 decreased the risk of pain and 23 increased the risk of pain. In both the discovery cohort and matched validation cohorts of 103 patients each, researchers found that patients carrying allele A of rs6265 polymorphism in BDNF had a lower risk of chronic postsurgical pain.

Perioperative gabapentin—Findings published in JAMA Surgery (online) suggest that perioperative administration of gabapentin may have a modest effect on promoting opioid cessation following surgery. The authors conducted a randomized, double-blind, placebo-controlled trial of 410 surgery patients who received either 1200 mg of gabapentin preoperatively followed by 600 mg of gabapentin three times a day postoperatively (n = 208) or active placebo (n = 202). In an intention-to-treat analysis, they found that perioperative gabapentin did not affect time to pain cessation. However, patients in the gabapentin cohort saw a 24 percent increase in the rate of opioid cessation after surgery. The authors found no significant difference across cohorts in number of adverse events or rate of medication discontinuation due to sedation or dizziness.

Postdischarge prescribing—Data from a study in the Journal of the American College of Surgeons (online) suggest that surgical patients' postdischarge opioid use may be predicted by usage the day prior to discharge. The authors reviewed information on 33 opioid naïve inpatients discharged to home following various surgical procedures. They found that, among patients discharged after postoperative day 1, the number of opioid pills used at home was associated with the number taken the day before discharge and patient age, but not type of surgery. The authors write that 85 percent of patients' home opioid requirements would be satisfied using the following guideline: If no opioid pills are taken the day before discharge, no prescription is needed; if 1 to 3 opioid pills are taken the day before discharge, a prescription for 15 opioid pills should be given at discharge; if 4 or more pills are taken the day before discharge, then a prescription for 30 opioid pills should be given at discharge. They estimate that adoption of such guidelines would reduce by 40 percent the number of opioid pills prescribed.