AAOS Now

Published 11/1/2017

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
Warfarin dosing—
Findings published in The Journal of the American Medical Association (online) suggest that, compared to clinically guided dosing, genotype-guided warfarin dosing may reduce the risk of adverse events for joint arthroplasty patients. The authors conducted a multicenter, randomized, clinical trial of 1,597 patients aged 65 years or older who underwent hip or knee arthroplasty, and of whom 808 were assigned to genotype-guided warfarin dosing. They found that adverse events (major bleeding, international normalized ratio of 4 or greater, or venous thromboembolism [VTE]) occurred in 87 patients (10.8 percent) in the genotype-guided group and 116 patients (14.7 percent) in the clinically guided warfarin dosing group. There were no deaths in either cohort.

Contrast agent warning—Medpage Today reports that the U.S. Food and Drug Administration (FDA) Medical Imaging Drugs Advisory Committee has voted in favor of a new warning for gadolinium-based contrast agents (GBCAs) used in magnetic resonance imaging (MRI). 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. Committee members voted 13-1, with one abstention, to recommend that FDA issue a new warning for GBCAs, and unanimously voted to recommend that the agency consider requiring industry to conduct more research to help determine if regulatory action may be necessary. The advisory committee findings are currently under consideration, and the FDA has not yet issued a formal warning.

Thermoregulating devices—The FDA Center for Devices and Radiological Health has issued a letter to healthcare providers, stating that use of thermoregulating devices during surgery—including forced air thermoregulating systems—has been demonstrated to result in less bleeding, faster recovery times, and decreased risk of infection for patients. The agency notes that some clinicians have elected not to use such systems during surgical procedures, including joint arthroplasty, due to concerns of increased risk of surgical site infection (SSI). "After a thorough review of available data," the letter states, "the FDA has been unable to identify a consistently reported association between the use of forced air thermal regulating systems and [SSI]. Therefore, the FDA continues to recommend the use of thermoregulating devices, including forced air thermal regulating systems, for surgical procedures when clinically warranted."

Preadmission frailty score—Data from a study in the Journal of the American College of Surgeons (online) suggest that preadmission frailty is independently associated with adverse discharge destination (death or discharge to a long-term, chronic, or acute care facility). The authors conducted a 4-year retrospective cohort study of 260 patients 65 years and older admitted to a Level I trauma center. They used the Canadian Study of Health and Aging Clinical Frailty Scale (CFS) and the laboratory Frailty Index (FI-lab) to determine preadmission frailty and on-admission frailty, respectively. They found that patients with a preadmission frailty as per CFS (CFS 6 or 7) experienced adverse discharge, and that severe frailty on admission as determined by FI lab (FI-lab > 0.4) was not associated with such outcomes. The authors conclude CFS may be used to triage hospital resources to alleviate adverse events in geriatric trauma patients, while FI-lab determined on admission may not be useful.

Opioids
Opioid prescribing—
A study published in JAMA Surgery (online) attempts to identify optimal ranges of initial durations of opioid prescriptions among opioid-naïve surgical patients. The researchers conducted a cohort study of 215,140 opioid-naïve patients who had undergone one of eight common surgical procedures, including anterior cruciate ligament repair, rotator cuff repair, or diskectomy. They observed that the median prescription lengths were 4 days for general surgery procedures, 4 days for women's health procedures, and 6 days for musculoskeletal procedures. However, the initial prescription lengths associated with the lowest requirements for refills were 9 days for general surgery, 13 days for women's health, and 15 days for musculoskeletal procedures. The researchers write that the data suggest an optimal length of opioid prescription of 6 to 15 days for the musculoskeletal procedures studied.

Risk of continued opioid use—Findings presented at the annual meeting of the American Academy of Pediatrics suggest that postoperative opioid pain medications prescribed after common procedures may become a pathway to continued, nonmedical opioid use by teens and young adults. Members of the research team reviewed data on nearly 90,000 privately insured opioid-naïve patients aged 13 to 21 years, who underwent one of 13 common surgeries for their age group, along with a control group. Following surgery, they found that the incidence of new persistent opioid use ranged from 2.7 percent to 15.2 percent across procedures (overall 4.8 percent), compared to 0.1 percent in the control group.

VTE
Factor Xa-inhibitors—
Data published in The Journal of Arthroplasty (online) suggest that the use of Factor Xa-inhibitors for prevention of VTE after joint arthroplasty procedures may be associated with an increased likelihood of bleeding and complication. The authors retrospectively reviewed information on 59 consecutive patients (31 knees, 28 hips) at a single center, who had no previous history of VTE, bilateral procedures, or medical conditions already requiring VTE chemoprophylaxis. Overall, 27 patients (46 percent) were given aspirin for VTE prophylaxis and 32 patients (54 percent) received a factor-Xa inhibitor. There were no new VTE complications in either cohort. However, 6 patients (18.7 percent) in the Xa-inhibitor group had a postoperative bleeding/wound complication (4 delayed healing/blistering, 1 hematoma/excessive ecchymosis, 1 readmission for cellulitis), compared to zero bleeding/wound complications in the aspirin group.

VTE and patient height—Data from a study published in Circulation: Cardiovascular Genetics (online) suggest that VTE may occur more frequently in taller persons. The researchers used a co-sibling design to rule out any genetic or environmental factors in their study of more than 2.7 million people. They observed male soldiers without previous VTE from enlistment (1969–2010) until 2012 and first-time pregnant women without previous VTE beginning from first pregnancy (1982–2012) until 2012. They found there was a graded decreased risk by lower height for both men and women; the risk of VTE was lowest in men shorter than 160 cm (5 feet, 3 inches) and women shorter than 155 cm (5 feet 1 inch).

Spine
Lumbar diskectomy revision—
A study published in Clinical Orthopaedics and Related Research (online) examines rates for revision diskectomy. The researchers reviewed data on 7,520 primary lumbar diskectomy patients from two national insurance databases in the United States. At 7-year follow-up, they found that revision rates ranged from 5.6 percent to 6.2 percent, with a total of 452 patients having undergone revision diskectomy. The researchers noted survivorship was lower for patients younger than 65 years, even when nondiskectomy lumbar surgeries were included. They found no difference in revision diskectomy rates or additional nondiskectomy lumbar surgery rates across geographic regions.

Osteoporotic spine fracture—According to a study conducted in the United Kingdom and published in Archives of Osteoporosis (online), osteoporotic vertebral fragility fracture (VFF) may be underreported, particularly by nonmusculoskeletal radiologists. The researchers reviewed information on 157 hip fracture patients aged 50 years or older who had undergone a radiological procedure involving the spine in the previous 6 years. They found VFF in 65 patients (41 percent), although only 30 VFFs (46 percent) had been reported. Of 35 unreported VFFs, 32 (91 percent) were from imaging reported by nonmusculoskeletal radiologists. Overall, only 16 VFF patients (25 percent) were documented as undergoing osteoporosis therapy at the time of hip fracture.

Hip
MOM adverse reactions—
A study conducted in Europe and published in The Journal of Bone & Joint Surgery (Sept. 20, 2017) suggests that implant-specific blood metal ion thresholds may be more effective in identifying metal-on-metal (MOM) hip arthroplasty patients who may be at risk of adverse reactions to metal debris (ARMD). The authors performed a validation study of 710 patients (803 MOM arthroplasties), divided into two cohorts: those with ARMD (n = 75) and those without (n = 635). They found that predictive values for implant-specific thresholds to distinguish between patients with and without ARMD ranged from 89.4 percent to 97.1 percent. Overall, implant-specific thresholds missed 20 patients with ARMD (2.8 percent), compared to 21 (3.0 percent) based on a fixed threshold of 3 µg/L for both cobalt and chromium, and 46 (6.5 percent) based on a fixed threshold of 10 µg/L for both cobalt and chromium.

Mortality after hip fracture—Findings from a study conducted in Australia and published in Archives of Osteoporosis (online) suggest that older patients with hip fractures are more likely to die within 12 months of hospital admission compared to noninjured individuals. The research team conducted a population-based, matched cohort study of 9,748 patients 65 years and older who had a hospital admission with a primary diagnosis of hip fracture as well as 9,748 noninjured individuals selected from the electoral roll. The team found that those in the hip fracture cohort were 3.62 times more likely to die within 12 months. The research team writes that hip fracture was likely a contributing factor in 72 percent of mortality and notes that mortality risk was higher in males than in females and in the 65- to 74-year age group.

Physical strain and hip OA—Data published in Deutsches Ärzteblatt International (Sept. 4) suggests an association between heavy lifting or long-term physical strain and risk of hip osteoarthritis (OA). The researchers performed a meta-analysis of five cohort studies and 18 case control studies conducted primarily in Europe. They found that regular lifting of heavy loads at work increased the risk of hip OA or total hip arthroplasty (THA) by more than 100 percent in men and by approximately 40 percent in women. In addition, physically demanding work consisting of a combination of activities such as dealing with heavy loads, heavy manual work, or prolonged walking and standing increased the risk of hip OA or THA by roughly 150 percent in men and 40 percent in women.

Knee
Meniscal risk after ACL reconstruction—
Findings published in The American Journal of Sports Medicine (AJSM; online) suggests that, for patients who undergo anterior cruciate ligament (ACL) reconstruction, risk of subsequent meniscal surgery may be higher in the index knee compared to the contralateral knee. The research team conducted a cohort study of 4,087 patients, 32 (0.78 percent) of whom underwent subsequent meniscal surgery in the index knee and 9 (0.22 percent) of whom underwent such surgery in the contralateral knee. They noted a 3.73 relative risk of subsequent meniscal surgery in the index knee compared with the contralateral knee, or a 0.57 percent absolute risk difference. After adjustment, the research team found that compared with bone–patellar tendon–bone (BPTB) autograft, allograft and hamstring autograft were risk factors for subsequent meniscal surgery in the index knee.

TKA failure—A study published in The Journal of Arthroplasty (JOA; online) examines reasons for failure of primary total knee arthroplasty (TKA). The authors retrospectively reviewed information on 18,065 primary TKAs to identify cause of failure and determine risk of revision surgery. Members of the research team found that hazard ratios for failure were 4.68 for patients with reported drug abuse, 3.52 for preoperative deformity and mechanical diagnosis, 1.99 for patients with a constrained condylar knee implant compared with a posterior stabilized implant, and 1.78 for preoperative posttraumatic and trauma diagnosis. Finally, they noted that advancing age was protective for failure, with a 0.61 hazard ratio.

Infected TKA device removal—A study published in JOA (online) looks at trends following removal of an infected TKA with spacer placement. The authors reviewed data on 18,533 Medicare beneficiaries who underwent removal of an infected TKA and placement of an antibiotic spacer for periprosthetic infection (PJI). At 1-year follow-up, they found that 691 patients (3.7 percent) had died in a hospital setting, 852 (4.5 percent) had undergone knee arthrodesis, 574 (3.1 percent) had undergone amputation, 2,683 (14.5 percent) had undergone a repeat débridement procedure without being reimplanted, 2,323 (12.5 percent) retained their spacer, and 11,420 (61.6 percent) had undergone spacer removal and reimplantation. The authors note a variety of outcomes following prosthesis removal and antibiotic spacer placement, and state that identification of independent risk factors for such outcomes may help develop and improve existing treatment strategies for such patients.

Shoulder and elbow
Distal biceps tendon rupture—
Findings presented in AJSM (online) compare single- and double-incision approaches for patients who undergo surgical management of distal biceps tendon rupture. The researchers analyzed 784 repairs, of which the single-incision technique was performed in 639 (81.5 percent) and the double-incision technique was performed in 145 (18.5 percent). They found that the double-incision approach was associated with a higher rate of posterior interosseous nerve palsy, heterotopic bone formation, and revision rate, while the single-incision approach was associated with increased risk of lateral antebrachial cutaneous nerve palsy. The researchers state that surgeons' years in practice, case volume, and fellowship training did not significantly affect complication rates.

Shoulder arthroscopy procedure time—According to a study in Arthroscopy (online), increased shoulder arthroscopy procedure time may be associated with increased likelihood of adverse short-term outcomes. Members of the research team conducted a retrospective, cohort study of 33,095 shoulder arthroscopy procedures, of which 7,027 (21.2 percent) were shorter than 45 minutes, 16,610 (50.2 percent) were between 45 and 90 minutes, and 9,458 (28.6 percent) were longer than 90 minutes. Compared to procedures of less than 45 minutes, they found increased risk of superficial SSI and overnight stay for procedures lasting between 45 and 90 minutes and for procedures of longer than 90 minutes. In addition, the research team notes that body mass index > 30 kg/m2 was an independent predictor of both overnight hospital stay and superficial SSI, while age > 60 years, female sex, American Society of Anesthesiologists class ≥ 3, and a history of diabetes mellitus, hypertension, or chronic obstructive pulmonary disease were additional predictors of overnight hospital stay.

Barbotage for rotator cuff calcific tendinitis—Data published in AJSM (online) suggest no significant difference in mid-term outcomes between barbotage combined with corticosteroid injection in the subacromial bursa (SAIC) compared to isolated SAIC for treatment of calcific tendinitis of the rotator cuff. The researchers conducted a randomized, controlled trial of 48 patients. At mean 5.1-year follow-up, they found no significant difference in outcomes across cohorts in Constant score, Western Ontario Rotator Cuff Index, or Disabilities of the Arm, Shoulder and Hand score, nor significant difference in calcification location and size, and Gärtner classification. The researchers found no significant complications in either cohort, but note that four patients in the barbotage group and 16 patients in the no-barbotage group underwent additional treatment during the follow-up period. However, a previous study based on the same patient population reported superior clinical and radiological outcomes in the barbotage cohort at 1-year follow-up.