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Published 8/1/2017

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
Frameless stereotaxic navigation systems—The U.S. Food and Drug Administration (FDA) has issued a safety communication regarding navigational accuracy errors associated with frameless stereotaxic navigation systems. The agency states that navigational accuracy errors may occur when using such navigation systems, and offers recommendations for surgeons to consider to mitigate associated risks to patients, including repeatedly assessing the navigational accuracy throughout a procedure when using a frameless surgical navigation system. Based on current information, the FDA states that overall benefits of using frameless stereotaxic navigation systems continue to outweigh the risks, and the agency has not determined that any particular system carries greater risk than others.

Diabetic patients with osteoporosis—A study in The Journal of Clinical Endocrinology & Metabolism (online) examines treatment options for patients with both type 2 diabetes and osteoporosis. The research team analyzed data from multiple human studies and recommended that metformin, sulfonylureas, DPP-4i, and GLP1-RA are preferred for the treatment of type 2 diabetes among osteoporotic patients. The investigators stated that insulin should be used with caution and with careful measures to avoid hypoglycemia, while thiazolidinediones and canagliflozin should be avoided. "Insulin therapy is the preferred method for achieving glycemic control in hospitalized patients with [type 2 diabetes] and fracture(s)," they wrote. "The treatment and monitoring of osteoporosis should be continued without important amendments because of the presence of [type 2 diabetes]."

Resistant bacteria—Findings published in the American Journal of Infection Control (May) suggest that many nursing home residents may be colonized with multidrug-resistant gram-negative bacteria (MDR-GNB). The researchers conducted a meta-analysis of eight studies covering 2,720 nursing home residents. They found that reported MDR-GNB colonization ranged from 11.2 percent to 59.1 percent, with a pooled prevalence of 27 percent.

Body fat assessment—Data from a study published in the journal PLoS ONE (online) suggest that waist-to-height ratio (WHtR) may offer a more accurate assessment of body fat than body mass index (BMI). The researchers calculated BMI, WHtR, waist circumference, waist-to-hip ratio, and waist/height0.5 for 81 adults, and compared the measurements to whole-body fat percentage (%FM) and visceral adipose tissue (VAT) mass, as quantified by dual energy X-ray absorptiometry. They found that the best predictor of both %FM and VAT mass was WHtR. "In the absence of more objective measures of central obesity and adiposity," the researchers write, "WHtR is a suitable proxy measure in both women and men." However, they note that the obesity cut points derived from the data will require validation in larger studies.

Mortality after hip fracture—Data published in the American Journal of Roentgenology (June) suggest that, among older adults with hip fracture, decreased thoracic paravertebral muscle size and attenuation as measured on routine computed tomography scans may be linked to increased mortality risk. The researchers reviewed data on 274 patients with a mean age of 81.3 years. After adjustment for demographic variables, American Society of Anesthesiologists classification, and Charlson comorbidity index, they found that increased likelihood of mortality within 10 years was significantly associated with decreased thoracic muscle size and a nonsignificant trend toward decreased lumbar muscle size and attenuation.

Displaced midshaft clavicular fractureFindings published in The Journal of Bone & Joint Surgery (JBJS; June 21) suggest that plate fixation for displaced midshaft clavicular fracture may reduce risk of nonunion compared to nonsurgical treatment. The research team conducted a meta-analysis of six randomized, controlled trials covering 614 patients. The investigators found that surgical treatment was associated with reduced likelihood of nonunion and that secondary operations for adverse events were performed less often among surgically treated patients. When plate removal was included, a secondary operation was performed in 17.6 percent of patients in the surgical cohort and 16.6 percent of patients in the nonsurgical cohort. At 1-year follow-up, the research team noted that mean Constant and Disabilities of Arm, Shoulder and Hand scores were somewhat better overall in the surgical cohort compared to the nonsurgical cohort.

Hip-fracture surgery—According to a study published in JBJS (June), the hour at which a hip fracture surgical procedure is performed (normal, after hours, overnight) may not affect the quality of the procedure or increase the probability of a postoperative adverse event. The authors reviewed the outcomes of 87,647 patients treated surgically for hip fracture, of which 68 percent underwent surgery after hours (5:00 p.m. to 12:00 a.m. or over the weekend), 31.1 percent underwent surgery during normal hours (7:00 a.m. to 5:00 p.m.), and 1 percent underwent surgery overnight (12:00 a.m. to 7:00 a.m.). At up to 6-month follow-up, they found that adverse outcomes were similar across all cohorts.

Joint arthroplasty

Obesity—A study in Clinical Orthopaedics and Related Research (CORR; July) finds that an increase in the number of obese patients undergoing total joint arthroplasty (TJA) may be related to growing trends of revision and infection following TJA. The research team reviewed data from the Nationwide Inpatient Sample database and other public sources. They found that 39 percent of total hip arthroplasty (THA) patients were obese in 1998, compared to 52 percent of THA patients in 2011. Similarly, 57 percent of total knee arthroplasty (TKA) patients were obese in 1998, compared to 70 percent of TKA patients in 2011. Over the same period, the research team identified increasing prevalence of obesity with rates of THA and TKA revision and rates of THA and TKA infection.

ED presentation—A study published in JBJS (June 21) looks at trends in emergency department (ED) visits following major joint arthroplasty surgery. The authors reviewed records on 152,783 patients from three states and found that 5,229 (3.42 percent) returned to the inpatient setting and 8,883 (5.81 percent) presented to the ED for care within 30 days. Of those who presented to the ED, 17.94 percent had a primary diagnosis of pain and 25.75 percent had both a primary and/or a secondary diagnosis of pain. Overall, patients who presented to the ED had more comorbidities and were more frequently nonwhite with public insurance compared to those who did not present to the ED.

Intermittent cervical traction—Data from a study in Spine (July 1) suggests that intermittent cervical traction (ICT) may offer short-term relief of neck pain. The researchers conducted a meta-analysis of seven randomized, controlled trials and found that treatment with ICT was associated with significantly lower pain scores immediately after treatment compared to placebo. They also noted that pain scores during the follow-up period and the neck disability index scores immediately after treatment as well as during the follow-up period did not differ significantly. However, they highlighted some risks of bias in the included studies and argued that additional high-quality trials are needed to clarify the long-term effects of ICT on neck pain.

Nonspecific cLBP—A study in the Annals of Internal Medicine (online) suggests that a manualized yoga program may not be inferior to physical therapy (PT) for patients with nonspecific chronic low back pain (cLBP). The researchers conducted a 12-week, single-blind, 3-group randomized noninferiority trial with subsequent 40-week maintenance phase for 320 racially diverse adults with cLBP. Participants received either 12 weekly yoga classes, 15 PT visits, or an educational book and newsletters. At 12-week follow-up, they found that patients in the yoga and PT cohorts were 21 and 22 percentage points less likely, respectively, than education participants to use pain medication at 12 weeks. At 1-year follow-up, the researchers noted that improvements in yoga and PT groups were maintained, with no differences between maintenance strategies. In addition, frequency of adverse events did not significantly differ between yoga and PT groups.

Hip and knee

THA instability—According to a study in The Journal of Arthroplasty (June), concomitant spinal deformity may be linked to THA instability. The researchers used standing stereoradiography to evaluate spinopelvic parameters, acetabular cup anteversion, and inclination of 139 THAs among 107 patients with sagittal spinal deformity. They found that the rate of THA dislocation was 8.0 percent, with a revision rate of 5.8 percent for instability. Overall, patients who sustained dislocations had significantly higher spinopelvic tilt, T1-pelvic angle, and mismatch of lumbar lordosis and pelvic incidence. The researchers note that among patients with dislocating THAs, 80 percent had safe anteversion, 80 percent had safe inclination, and 60 percent had both parameters within the safe zone.

Heparin—A study conducted in Norway and published in CORR (online) suggests that risk of postoperative complication may be comparable whether low-molecular-weight heparin (LMWH) prophylaxis is initiated prior to or following THA. The authors reviewed data on 25,163 patients undergoing THA who were included in the Norwegian Arthroplasty Register and the Norwegian National Patient Register. Overall, 9,977 patients (40 percent) received preoperative LMWH and 15,186 patients (60 percent) received postoperative LMWH. After adjustment for age, sex, operation time, year of surgery, and American Society of Anesthesiologists class, the authors found no major differences across cohorts in bleeding events, thromboembolic episodes, other postoperative clinical complications, 6-month mortality, or readmission rates. The authors noted that the postoperative approach reduced costs, decreased risks related to neuraxial anesthesia, and facilitated same-day admissions.
Single or double bundle ACL reconstruction—Data from a study in CORR (online) suggest similar risk of revision following anterior cruciate ligament (ACL) reconstruction using a single- or double-bundle hamstring tendon technique. The authors reviewed data on 60,775 patients from three national registers in Denmark, Norway, and Sweden. They found that the ACLs in 994 patients were reconstructed with double-bundle hamstring tendon grafts, 51,991 with single-bundle hamstring tendon grafts, and 7,790 with single-bundle bone-patellar tendon-bone grafts. At 5-year follow-up, they found that survival was 96.0 percent for the double-bundle group, 95.4 percent for the single bundle hamstring tendon group, and 97.0 percent for the single-bundle bone-patellar tendon-bone group.

ACL in adolescent females—A research letter published in JAMA Pediatrics (online) notes a strong increase in the rate of ACL reconstruction among adolescent females. The researchers reviewed data on 283,810 ACL reconstructions performed in the United States from 2002 through 2014. They found that ACL reconstruction rates per 100,000 person-years rose 22 percent overall, from 61.4 in 2002 to 74.6 in 2014. Overall, males were more likely than females to undergo ACL reconstruction. However, the rate of ACL reconstruction for females grew 34 percent over the study period, compared to 13 percent for males. In addition, females and males aged 13 to 17 years saw the highest absolute increases in ACL reconstruction rates. The researchers write that the rise in rates among adolescent female patients was so steep that, "by the end of the study period in 2014, they had a higher rate of ACL reconstruction than any other age-sex strata."

Shoulder and elbow
Radial extracorporeal shock wave therapy—According to a study in The American Journal of Sports Medicine (online), radial extracorporeal shock wave therapy (rESWT) may offer little additional benefit to patients treated with supervised exercise for subacromial shoulder pain. The authors conducted a randomized, controlled trial of 143 patients with subacromial shoulder pain who were treated with supervised exercise and either rESWT or sham rESWT. At 24-week follow-up, they found that patients in both cohorts displayed similar improvement in Shoulder Pain and Disability Index (SPADI) scores compared with baseline. However, patients with calcification in the rotator cuff who were treated with rESWT displayed a greater improvement in SPADI scores compared to sham rESWT patients at 24 weeks.