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AAOS Now

Published 3/1/2018

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).

Knee
Minority access—According to a study published in Arthritis Care & Research, disparities in total knee arthroplasty (TKA) utilization and complication rates may negatively impact racial minorities in the United States. The authors used the Osteoarthritis Policy Model to estimate quality-adjusted life years (QALYs) lost for black patients with knee osteoarthritis due to differences in TKA offer, acceptance, and complication rates. They found that black men and women gain 64,100 QALYs from current TKA use. If offer and complications rates matched those of white patients, they would gain an additional 72,000 QALYs. "Because these additional gains are unrealized," the authors write, "we call this a loss of 72,000 QALYs." They estimate that black Americans lose 67,500 QALYs due to lower offers, 15,800 QALYs due to lower acceptance, and 2,600 QALYs due to increased complication rates.

bDMARDs—Data from a study conducted in Denmark and published in The BMJ (online) suggest that introduction of biological disease-modifying anti-rheumatic drugs (bDMARDs) may have been linked to a decrease in incidence of TKA. The authors reviewed data on 30,404 patients with incident rheumatoid arthritis (RA) and 297,916 matched control participants. They found that among patients with RA, the incidence rate of TKA increased from 1996 to 2001. After the introduction of bDMARDs in 2003, the rate of TKA steadily decreased. Among the general population, the incidence of TKA increased overall from 1996 to 2016. The authors note that the incidence of total hip arthroplasty had already started to decrease prior to bDMARD introduction.

Subtubercle tibial osteotomy—A study published in The Journal of Bone & Joint Surgery (JBJS; Jan. 3) suggests that subtubercle tibial osteotomy (STO) procedures using the Ilizarov technique for symptomatic varus knee deformity may be associated with high knee survival rates without arthroplasty and significant improvement in clinical status. The authors reviewed information on 72 STO procedures (61 patients) treated with STO using the Ilizarov technique to correct a varus deformity of the proximal part of the tibia. They found that radiographic measurements, including mechanical axis deviation, medial proximal tibial angle, and joint line congruence angle, significantly improved after deformity correction. In addition, among patients with a preoperative flexion contracture, proximal posterior tibial angle significantly increased toward normal values. A survival analysis demonstrated a rate of native knee-joint survival without conversion to arthroplasty of 94.2 percent at 5 years, 84.0 percent at 10 years, and 51.3 percent at 15 years.

Synovial fluid markers—Data published in The American Journal of Sports Medicine (online) suggest that synovial fluid profile may help predict articular cartilage degeneration following anterior cruciate ligament (ACL) repair. The authors conducted a longitudinal cohort study of 26 patients who underwent ACL repair at a mean 8.5 weeks after injury and who had synovial fluid aspirated at the time of surgery. They found that higher synovial fluid sulfated glycosaminoglycan concentrations at the time of surgery were associated with worse cartilage composition during the first 3 years after surgery, based on T1ρ and T2 quantitative magnetic resonance imaging.

Hip
Radiography—A research study published in the Journal of the AAOS (Jan. 1) compares radiation exposure to radiosensitive organs for patients undergoing radiography with native hips and total hip arthroplasty (THA) implants. The authors conducted a cadaver study with detection probes placed at six locations: stomach, sigmoid colon, right pelvic wall, left pelvic wall, pubic symphysis, and anterior pubic skin. Compared to native hip, they found that THA was associated with up to 3 times the radiation exposure to radiosensitive organs when using automatic exposure control and up to approximately 1.5 times with a manual protocol.

Crosslinked polyethylene—According to a study in Clinical Orthopaedics and Related Research (CORR; online), crosslinked polyethylene (XLPE) may be associated with reduced wear, osteolysis, and revision rates compared with conventional polyethylene (CPE) for THA patients. Members of the research team conducted a randomized, controlled trial of 236 primary THAs (226 patients) at a single institution. Of 85 unrevised THAs available at minimum 14-year follow-up, they found that the mean steady-state linear wear rate for THAs with XLPE liners was lower than the mean linear wear rate for the THAs with CPE liners. In addition, at 15-year follow-up, the researchers note that the cumulative incidence of revision was lower in the XLPE group than in the CPE group. Overall, 9 percent (four of 46) of hips in the XLPE group and 46 percent (18 of 39) of hips in the CPE group displayed osteolysis of any size.

Shoulder and elbow
Unplanned ED visits—A study published in the Journal of Shoulder and Elbow Surgery (online) looks at unplanned visits to the emergency department (ED) following elective outpatient rotator cuff repair (RCR). The researchers reviewed data on 1,306 outpatient RCRs performed at a single healthcare system. They found that 90 RCR patients returned to the ED or an urgent care center within 7 days, 34 of them for avoidable diagnoses. The researchers found that pain was the most common avoidable diagnosis, but also noted that return visits for urinary retention were significantly more common among RCR patients compared to a control cohort of 5,825 nonRCR patients.

Spine
AIS screening recommendation—The U.S. Preventive Services Task Force has released a final recommendation on screening for adolescent idiopathic scoliosis (AIS). The group reports insufficient evidence to recommend for or against screening for idiopathic scoliosis in children and adolescents aged 10 to 18 years who do not have any signs or symptoms. The task force reviewed data on 448,276 patients across 14 studies and found that screening can detect AIS, and that bracing and possibly exercise treatment can interrupt or slow progression of curvature in adolescence. "However," the authors write, "there is little or no evidence on long-term outcomes for AIS treated in adolescence, the association between curvature at skeletal maturity and adult health outcomes, the harms of AIS screening or treatment, or the effect of AIS screening on adult health outcomes."

Patient safety
Discharge to home—Data published in JBJS (Jan. 17) suggest that it may be safe for total joint arthroplasty (TJA) patients to be discharged directly home, even if they live alone. The authors conducted a prospective study of 769 patients who underwent primary, unilateral THA or TKA, 138 of whom lived alone. They found that patients living alone more commonly stayed an additional night in the hospital and used more home health services. However, the authors found no significant difference across cohorts in complications, unplanned clinical events, functional outcomes, pain relief, or 90-day satisfaction scores.

PJI—Findings published in JBJS (Jan. 17) suggest that next-generation DNA sequencing may be used to help identify causative organisms associated with periprosthetic joint infection (PJI). The authors collected samples from 65 revision arthroplasties (39 knees and 26 hips) and 17 primary arthroplasties (eight knees and nine hips). They found that among 28 revisions considered to be infected, cultures were positive in 17 cases and next-generation sequencing was positive in 25 cases, with concordance across both methods in 15 cases. The authors note that next-generation sequencing identified microbes in nine of 36 aseptic revisions with negative cultures and in six of 17 primary TJAs.

Postoperative complications—A study published in BMC Medicine (online) examines geriatric factors linked to complication after elective surgery. The researchers conducted a meta-analysis of 44 studies covering 12,281 patients and found that the pooled incidence of postoperative complications was 25.17 percent. They found that frailty, cognitive impairment, depressive symptoms, and smoking were associated with increased risk of postoperative complication. However, traditionally assessed prognostic factors such as age and American Society of Anesthesiologists status were not.

Preoperative PT intervention—According to a study published in CORR (January), a one-on-one preoperative physical therapy (PT) education session along with web-based information may help reduce time to PT discharge for patients undergoing unilateral THA or TKA. Members of the research team conducted a prospective study of 126 typical arthroplasty patients, 63 of whom received a one-time, one-on-one session with a physical therapist and were given access to a lateralized, joint-specific microsite with detailed information on exercises, transfers, ambulation, and activities of daily living, and 63 of whom received no additional information. Compared to patients in the control cohort, patients in the intervention cohort had fewer postoperative inpatient PT visits and achieved readiness to discharge from PT more quickly. However, the researchers note that there was no significant difference in length of stay or Western Ontario and McMaster Universities Osteoarthritis Index scores at 6-week follow-up.

Fracture
Mortality predictors—A study published in the Journal of Orthopaedic Trauma (JOT; January) examines predictive models for mortality after hip fracture surgery. Researchers reviewed data on 535,475 hip fracture patients older than 50 years of age from the National Inpatient Sample database, and identified the following eight essential predictors for mortality: age, timing of surgery, male sex, congestive heart failure, pulmonary circulation disease, renal failure, weight loss, and fluid and electrolyte disorders.

In a second study published in JOT (January), the authors reviewed data on 1,050 consecutive patients who underwent hip fracture surgery and identified the following nine predictors for 30-day mortality: age ≥ 85 years, in-hospital fracture, signs of malnutrition, myocardial infarction, congestive heart failure, current pneumonia, renal failure, malignancy, and serum urea > 9 mmol/L.

Supplements—Data published in The Journal of the American Medical Association (Dec. 26) suggest that use of calcium or vitamin D supplements may not be associated with a reduction in risk of fracture for older adults. The researchers conducted a meta-analysis and systematic review of 33 randomized trials covering 51,145 adults aged 50 years or older. Compared with placebo or no treatment, they found that calcium or vitamin D supplementation had no significant association with risk of hip fracture or with incidences of nonvertebral fracture, vertebral fracture, or total fractures. In subgroup analyses, the researchers noted generally consistent similar results regardless of calcium or vitamin D dose, sex, fracture history, dietary calcium intake, and baseline serum 25-hydroxyvitamin D concentration.