Published 8/1/2016

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).

Continuing usage—Data from a study published in Pain (June) suggest that many patients continue to use opioids for months after undergoing an arthroplasty procedure. The authors conducted a prospective study of 574 total knee arthroplasty (TKA) and total hip arthroplasty (THA) patients who completed validated, self-reported measures of pain, functioning, and mood and who were longitudinally assessed for 6 months following surgery. They found that 53.3 percent of TKA patients and 34.7 percent of THA patients who reported opioid use on the day of surgery continued to use opioids at 6 months. Additionally, among patients who were opioid naïve on the day of surgery, 8.2 percent of TKA patients and 4.3 percent of THA patients were using opioids at 6-month follow-up. For opioid-naïve patients, day of surgery predictors for 6-month opioid use included greater overall body pain, greater affected joint pain, and greater catastrophizing. For both patient cohorts, decreases in overall body pain from baseline to 6 months were associated with decreased likelihood of being on opioids at 6 months. However, the authors note that change in affected joint pain was not predictive of opioid use at 6 months.

Nonmedical use—A study from the National Institute on Alcohol Abuse and Alcoholism (NIAAA) and reported in the Journal of Clinical Psychiatry (June) finds that nonmedical use of prescription opioids more than doubled among adults in the United States from 2001–2002 to 2012–2013. The researchers analyzed data from the NIAAA's National Epidemiologic Survey on Alcohol and Related Conditions-III and found that more than 11 percent of Americans report nonmedical use of prescription opioids at some point in their lives—up from 4.7 percent 10 years earlier. In addition, the number of people who meet the criteria for prescription opioid addiction has substantially increased during this time frame, with 2.1 million adults reporting signs and symptoms of "nonmedical prescription opioid use disorder" as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition.

Monitoring programs—Findings from a study published in the journal Health Affairs (online) suggest that implementation of state-level prescription drug monitoring programs to detect high-risk prescribing and patient behaviors may be linked to an average reduction of 1.12 opioid-related overdose deaths per 100,000 population in the year following implementation. In addition, states whose programs had robust characteristics—including monitoring greater numbers of drugs with abuse potential and updating their data at least weekly—saw greater reductions in deaths, compared to states whose programs lacked such characteristics.

Biofilms—Data from a study published in Clinical Orthopaedics and Related Research (CORR; July) suggest that antibiotic-tolerant biofilm may be a factor in poor results following irrigation and débridement for acute periprosthetic joint infection in TKA patients. The research team cultured methicillin-sensitive biofilm on TKA materials and exposed the biofilm to increasing doses of cefazolin. Although live biofilm mass was reduced by exposure to cefazolin when compared with biofilm mass in controls, the researchers found no further reduction after higher doses. They note that at the highest concentration tested, residual viable biofilm remained, and there were no differences in percent biofilm survival among cobalt-chromium, polymethylmethacrylate, and polyethylene materials. The research team writes that tolerance was a phenotypic phenomenon, as increasing cefazolin exposure did not result in changes in minimum inhibitory concentration compared with controls.

Disinfection protocol—Two studies published in CORR (July) suggest that use of a preoperative chlorhexidine gluconate disinfection protocol may reduce the risk of periprosthetic infections after THA and TKA. In the first study, researchers looked at data on 998 THA patients who used chlorhexidine cloths prior to surgery and 2,846 THA patients who underwent standard perioperative disinfection only. They found that patients in the intervention group were at reduced risk of infection compared to those in the control group. The researchers state that no differences were detected across cohorts when patients were stratified based on risk category, but note that the findings were underpowered.

In a related study, the research team reviewed data on 991 TKA patients who used chlorhexidine cloths before surgery and 2,726 TKA patients who did not. They found that use of the preoperative chlorhexidine cloth skin preparation protocol was associated with reduced relative risk of periprosthetic infection after TKA. However, when stratified by risk category, periprosthetic infection risk reduction was seen in the medium-risk category, but there was no significant difference across the low- and medium-risk groups. "Although future multicenter randomized trials will need to confirm these preliminary findings," the research team writes, "the intervention is inexpensive and is unlikely to be risky and therefore might be considered on the basis of this retrospective, comparative study."

Lumbar fusion—Findings from a study published in The Spine Journal (online) suggest that obesity may not contraindicate lumbar fusion surgery for appropriate obese and overweight patients. The researchers conducted a propensity-matched case control study of 246 patients who underwent posterior instrumented lumbar spinal fusion at a single center. There were 82 matched cases across three cohorts: body mass index (BMI) ≥ 20 to 25 kg/m2 (normal); BMI ≥ 25 to < 30 kg/m2 (overweight); and BMI ≥ 30 to 40 kg/m2 (obese). The researchers found that estimated blood loss and surgical time were significantly greater among overweight and obese patients. However, improvements in Oswestry Disability Index, Short Form-36 Physical Composite Summary scores, and back pain and leg pain scores were similar across cohorts, as were revision rates and time between index and revision surgery.

CSM—A study conducted in Canada and published in Neurosurgery (July) examines predictors of perioperative complication for patients with cervical spondylotic myelopathy (CSM). The authors reviewed prospectively collected data on 479 surgical CSM patients and found that 78 experienced a total of 89 perioperative complications. On univariate analysis, they found that major clinical risk factors included ossification of the posterior longitudinal ligament (OPLL), number of comorbidities, comorbidity score, diabetes mellitus, and coexisting gastrointestinal and cardiovascular disorders. In addition, patients who underwent a 2-stage surgery and/or procedure of longer operative duration were at greater risk of perioperative complications. The authors state that their final prediction model consisted of diabetes mellitus, number of comorbidities, surgical duration, and OPLL.

CLBP— A study conducted in Sweden and published in The Spine Journal (May) examines long-term outcomes for patients who undergo spinal fusion for the treatment of chronic low back pain (CLBP). The research team conducted a prospective, randomized trial of 294 patients who had at least 2 years' duration of CLBP. At mean 12.8-year follow-up, 85 percent of patients were available. With the exception of an intention-to-treat model, scores obtained using the primary outcome measure (Global Assessment of back pain) were significantly better for fusion patients. However, the research team notes that Oswestry Disability Index, visual analogue scale, work status, pain medication, and pain frequency were similar across cohorts. The researchers state that the "discrepancy between primary and secondary outcome measures prevents a strong conclusion on whether to recommend fusion in nonspecific low back pain."

Hip and knee
Computer-assisted TKA—Data from a study conducted in Germany and published in Orthopedics (May/June supplement) suggest that computer-assisted navigation of TKA may be associated with a reduced rate of revision, compared to conventional procedures. The authors reviewed 10-year follow-up data on 96 TKA procedures (50 navigated and 46 conventional), and found that eight TKAs had been revised for aseptic loosening—one in the navigated cohort and seven in the conventional cohort. The authors state that after conclusion of the follow-up, 9.8 percent of the navigated TKAs and 17 percent of the conventional TKAs were found to have undergone aseptic loosening.

Triamcinolone acetonide and hyaluronic acid—According to a study published in The Journal of Bone & Joint Surgery (JBJS; June 1), triamcinolone acetonide and hyaluronic acid may offer similar improvement in pain and function for patients with knee osteoarthritis (OA). The research team conducted a prospective, randomized, double-blind trial of 99 patients with knee OA who were treated with a single-shot, intra-articular injection of either 6 mL of hylan G-F 20 (hyaluronic acid) or 6 mL of a solution comprising 1 mL of 40-mg triamcinolone acetonide and 5 mL of 1 percent lidocaine with epinephrine. At 6-month follow-up, the research team noted similar improvements in knee pain, knee function, and range of motion across both cohorts. However, patients in the triamcinolone acetonide cohort displayed better pain improvement from 24 hours until 1 week after injection, and 2 weeks after injection, patients who took triamcinolone acetonide also had better knee functional improvement.

Outpatient THA—Data from a study published in CORR (online) suggest that outpatient THA may be safe and effective for certain patients. The authors conducted a prospective, randomized study of 220 patients younger than 75 years who underwent THA at one of two centers. Of 112 patients randomized to outpatient surgery, 85 (76 percent) were discharged as planned. Of the remaining 27 patients, 26 were discharged after one night in the hospital and one was discharged after two nights. Of 108 patients randomized to inpatient surgery with an overnight hospital stay, 81 (75 percent) were discharged as planned. Of the remaining 27, 18 met discharge criteria on the day of their surgery and elected to leave the same day, and nine patients stayed 2 or more nights. The authors note that, on the first day following surgery, outpatients had more pain (at home) as measured by the visual analog scale than inpatients. However, at 4-week follow-up, they found no difference across cohorts in the number of phone calls and emails with the surgeon's office. As 24 percent of patients planning to have outpatient surgery were unable to be discharged the same day, the authors recommend that facilities that can accommodate an overnight stay should be available.

Foot and ankle
Achilles tendon rupture—A study published in The American Journal of Sports Medicine (AJSM; online) compares outcomes of surgical and nonsurgical treatment of acute Achilles tendon rupture. The authors conducted a randomized, controlled trial of 60 patients with acute Achilles tendon rupture treated nonsurgically with 1 week of cast immobilization, followed by a functional orthosis for 6 weeks, with full weight bearing after 1 week and active plantar flexion after 5 weeks; or treated surgically, via simple end-to-end open repair, followed by a postoperative regimen identical to nonsurgical treatment. At 18-month follow-up, they found that the mean Leppilahti score was 79.5 in the surgical cohort and 75.7 in the nonsurgical cohort. Overall, angle-specific peak torque results of affected legs demonstrated that surgery was associated with faster and better recovery of calf muscle strength over the entire range of motion of the ankle joint compared to nonsurgical treatment. In addition, the RAND 36-Item Health Survey indicated better results in the domains of physical functioning and bodily pain for surgical patients.

Idiopathic scoliosis—According to findings published in Science (June 10), irregular fluid flow through the spinal column linked to gene mutations may be associated with the development of idiopathic scoliosis (IS). The research team demonstrated that ptk7 mutant zebrafish exhibited defects in ependymal cell cilia development and cerebrospinal fluid (CSF) flow. However, transgenic reintroduction of ptk7 in motile ciliated lineages restored cerebrospinal fluid flow and prevented scoliosis in ptk7 mutants. "Together, our results indicate a critical role for cilia-driven CSF flow in spine development, implicate irregularities in CSF flow as an underlying biological cause of IS, and suggest that noninvasive therapeutic intervention may prevent severe scoliosis," the research team writes.

Physical activity—A study published in The Journal of Bone and Mineral Research (online) finds that physical activity (PA) may have a beneficial effect on bone in children, even when the child may be genetically predisposed to lower adult bone mineral density (BMD). The research team surveyed 918 children of European ancestry to estimate hours per day spent in total, high-, and low-impact PA. They found that BMD genetic score (based on percent of BMD-lowering alleles) was negatively associated with bone mineral content Z-score. However, total PA was positively associated with bone Z-scores, with the associations observed even for children with lower than average bone Z-scores. The research team writes that some of its findings are exploratory, and that independent verification is warranted.

Sports medicine
PRP—Evidence published in AJSM (online) supports the use of a single injection of leukocyte-rich platelet-rich plasma (LR-PRP) in the treatment of tendinopathy. The authors conducted a meta-analysis of 18 randomized controlled trials covering 1,066 participants who were treated for tendinopathy using autologous blood, PRP, platelet-poor plasma, or autologous conditioned plasma. At minimum 3-month follow-up, they found that the most significant outcomes in the PRP groups were seen in those treated with highly cellular (LR-PRP) preparations. In addition, when the LR-PRP system types were grouped, the authors noted a strong positive effect when compared with leukocyte-poor PRP. Regarding control groups, the authors found no clear difference in different types of control injections: saline, local anesthetic, corticosteroid, or dry needling.

ACL injury—According to a study published in JBJS (June 15), increased lateral tibial slope may be associated with increased risk of anterior cruciate ligament (ACL) injury in male college football players. The research team reviewed data on 90 male U.S. National Collegiate Athletic Association Division I college football players who underwent magnetic resonance imaging for a knee injury. A univariable analysis found that increased medial tibial plateau slope, increased lateral tibial plateau slope, and narrower lateral femoral condyle were significantly associated with ACL injury. However, multivariable analysis revealed that increased lateral tibial slope was the sole independent predictor of ACL injury.

Heat stroke—Data from a study presented at the annual meeting of the National Athletic Trainers' Association finds that adoption of heat acclimatization protocols has been associated with a reduction in the number of deaths related to heat stroke among high school football players. The researchers reviewed information on 48 high school football preseasons across 14 states that had adopted heat stroke prevention guidelines since 2011. They found only one exertional heat stroke death during the preseasons, and the incident was associated with violations of school policy. The guidelines were developed in association with the American Academy of Pediatrics, the American College of Sports Medicine, and the U.S. Centers for Disease Control and Prevention.