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AAOS Now

Published 9/1/2018

Second Look—Clinical

Hip and knee

THA and QALY—A study published in the Journal of Arthroplasty (online) found that total hip arthroplasty (THA) may improve pain, quality of life, and function. Researchers assessed 100 patients in Switzerland older than 83 years of age who underwent THA for severe osteoarthritis (OA) at a single institution between January 2009 and December 2016. They observed an overall complication rate of 12 percent. Thirty-day and one-year mortality rates were 3 percent and 6 percent, respectively. The average Harris hip score (HHS) increased from 50 points to 93 points following THA. Most patients (98 percent) had a minimally significant improvement in HHS, whereas 75 percent had moderate improvement. The average quality-adjusted life-year (QALY) was four years.

Robotic arm TKA—Robotic arm–assisted total knee arthroplasty (TKA) may be associated with better outcomes compared to conventional jig-based TKA, according to the results of a prospective cohort study published in The Bone & Joint Journal (online). The study included 80 consecutive patients undergoing primary TKA at a single institution between January 2016 and September 2017. Among them, 40 underwent conventional jig-based TKA and 40 underwent robotic arm–assisted TKA. A single surgeon performed all surgical procedures using the medial parapatellar approach with identical implant designs and standardized postoperative inpatient rehabilitation. Robotic arm–assisted TKA was associated with reduced postoperative pain, decreased analgesia requirements, decreased reduction in postoperative hemoglobin levels, shorter time to straight leg raise, decreased number of physiotherapy sessions, and improved maximum knee flexion at discharge. The median time to hospital discharge was 77 hours for the robotic arm–
assisted TKA cohort compared to 105 hours for the conventional jig-based TKA group.

Bikini incision for THA—Use of a short oblique “bikini” skin crease incision appears to be a safe direct anterior approach for THA, according to a study published in The Bone & Joint Journal (online). Researchers administered a follow-up questionnaire to 964 patients two to four years after they underwent THA. Among them, 59 percent received a longitudinal incision, and 41 percent received a bikini incision. The questionnaire included the Oxford Hip Score (OHS) and the University of North Carolina “4P” scar scale (UNC4P), as well as two items assessing aesthetics and scar numbness. OHS scores were similar, but the mean UNC4P score was slightly better in the bikini incision group, with more patients reporting aesthetic satisfaction. Reported numbness was higher in the longitudinal incision group. Researchers observed no difference in revision rates, abduction angle of the acetabular component, position of the stem, or rates of heterotopic ossification. However, they noted that the bikini method should be used by surgeons only after they have gained experience with the classic longitudinal incision.

Glucose variation in THA/TKA—Higher postoperative glucose variability may be associated with increased rates of infection, longer hospital stays, and mortality following THA and TKA, according to a study published in The Journal of Bone & Joint Surgery (JBJS; July 5).

Researchers assessed 2,360 patients who underwent THA and 2,698 who underwent TKA between 2001 and 2017 at a single center; 1,007 patients (19.9 percent) had diabetes. Each patient had a minimum of two postoperative glucose measurements per day or more than three overall values. Study results indicated that for every 10 percentage-point increase in the coefficient of glycemic variability, the length of stay increased by 6.1 percent, the risk of mortality increased by 26 percent, and the risks of periprosthetic joint infection and surgical site infection increased by 20 percent and 14 percent, respectively.

Hip replacement revision—A study published in The Lancet Infectious Diseases (online) found several modifiable factors associated with risk of revision for prosthetic joint infection (PJI) after primary hip replacement.

The prospective, observational cohort study included 623,253 hip procedures conducted between April 1, 2003, and Dec. 31, 2013, in England and Wales. During that time, 2,705 primary procedures were subsequently revised for an indication of PJI after a median follow-up of 4.6 years (interquartile range, 2.6–7.0 years). Factors associated with increased revision because of PJI were male sex, younger age (< 60 years), elevated body mass index, diabetes, dementia, previous septic arthritis, fractured femur, and lateral surgical approach. Ceramic bearings were associated with a lower risk of revision due to PJI than metal bearings.

ACL injury—According to research presented at the American Orthopaedic Society for Sports Medicine’s annual meeting, young athletes may be more predisposed to anterior cruciate ligament (ACL) injury if they are fatigued. Eleven professional health observers reviewed drop-jump and vertical-jump video in 85 track and field, basketball, volleyball, and soccer athletes (mean age, 15.4 years). They found that 44.7 percent had an increased risk of injury after intense aerobic exercise. Injury risk also was associated with the athletes’ level of fatigue: 14 of 22 athletes who demonstrated more than 20 percent fatigue showed an increased risk of ACL injury. Female athletes and athletes older than 15 years of age also demonstrated an increased risk of injury.

Patient satisfaction after TKA—A retrospective cohort study published in The Bone & Joint Journal (online) found that the overall rate of satisfaction following TKA did not change from one year to five years (91.7 percent versus 90.1 percent, respectively). Researchers identified 1,369 patients from an arthroplasty database who had undergone primary TKA but not revision TKA for OA.

Approximately half of patients (n = 53/114) who were dissatisfied with their outcomes at one-year post-TKA had become satisfied at five years. Among those who were satisfied at one year, just 6 percent (n = 74/1,255) became dissatisfied at five years. Patients with lung disease, depression, and back pain, and those who had undergone unilateral TKA or had a worse preoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score were more likely to be dissatisfied at one year following TKA. Patients with gastric ulceration and a worse WOMAC stiffness score were more likely to be persistently dissatisfied at five years following TKA. The researchers noted that acknowledging and addressing these patient factors may improve outcomes and satisfaction.

Atypical femoral fractures—Among hip and femoral fractures, the incidence of atypical femoral fractures (AFFs) was 2.95 percent, according to a retrospective study published in Osteoporosis International (online).

Researchers assessed medical records and radiographs of 6,644 hip and femoral fractures of patients from eight tertiary referral hospitals. Of the AFFs, 90 were subtrochanteric and 106 were femoral shaft fractures. Independent risk factors for AFFs included osteopenia or osteoporosis, use of bisphosphonates (BPs), rheumatoid arthritis, increased anterior and lateral femoral curvatures, and thicker lateral femoral cortex. Patients with AFFs who received treatment with BPs were more likely to have problematic fracture healing than those who did not receive BPs.

Reimbursement methods for hip fracture—Beneficiaries of Medicare Advantage (MA) may experience a shorter course of rehabilitation, be more likely to be discharged to the community successfully, and be less likely to experience a 30-day hospital readmission compared to those covered by Medicare fee-for-service (FFS), according to a retrospective cohort study published in PLOS Medicine (online).

Researchers assessed differences in health service utilization and outcomes in 211,296 FFS-covered patients and 75,554 MA-covered patients in skilled nursing facilities (SNFs) following hip fracture hospitalization between Jan. 1, 2011, and June 30, 2015. The MA population spent 5.1 fewer days in an SNF and received 463 fewer minutes of total rehabilitation therapy during the first 40 days of admission compared to the FFS population.

In addition, MA-covered patients had a 1.2 percentage point lower 30-day readmission rate, 0.6 percentage point lower rate of becoming a long-stay resident, and a 3.2 percentage point higher rate of successful discharge to the community.

Shoulder and elbow

Arthroscopic subacromial decompression—Arthroscopic subacromial decompression (ASD) was shown to provide no benefit over diagnostic arthroscopy at 24 months in patients with shoulder impingement, according to a study published in The BMJ (online).

Researchers for the Finnish Subacromial Impingement Arthroscopy Controlled Trial (FIMPACT) enrolled 210 patients with symptoms consistent with shoulder impingement and randomly assigned them to ASD, diagnostic arthroscopy (placebo control), or exercise therapy. Primary outcome measures were shoulder pain at rest and with arm activity at 24 months. In the primary intent-to-treat analysis (ASD compared to diagnostic arthroscopy), the researchers found no clinically relevant between-group differences in the two primary outcomes.

Trauma and surgery

Microfracture surgery—Twenty years ago, many NBA players underwent microfracture surgery, a procedure that involves drilling small holes through the articular cartilage and into the subchondral bone, with the goal of causing stem-cell growth. Articular cartilage is necessary for NBA players, as they can put up to 10 times their body weight on their knees during play. Although the early results of this procedure were promising, many doctors are trending away from the surgery.

A study recently published online in the journal Cartilage found that the failure rate of microfracture surgery was 66 percent compared to 51 percent for osteochondral autograft transfer surgery; time to failure for the two procedures was four years and 8.4 years, respectively. An article published in the Chicago Tribune discussed the “rise and fall” of microfracture in the NBA.

Risk of nonunion—Fracture type and morphology appear to significantly influence nonunion risk and time to union following intramedullary nailing for tibial fracture, according to a retrospective review published in the Journal of Orthopaedic Trauma (July).

Researchers used data from a Scottish trauma center to identify 1,003 adult tibial fractures treated via intramedullary nailing between 1985 and 2007. They assessed risk factors such as observed nonunion, final union time, age, fracture type, American Orthopaedic Trauma Association/Arbeitsgemeinschaft für Osteosynthesefragen (OTA/AO) classification, and smoking status.

The overall nonunion rate was 12 percent, with a median healing time of 18 weeks. Age had a significant influence on nonunion, with the highest risk found in middle-aged adults. Fracture type and OTA/AO classification had a strong influence on nonunion rate and time to union, with OTA/AO type B having a nonunion rate of 15 percent in closed injuries and type C having a rate of 61 percent in open injuries. Compartment syndrome and smoking status significantly extended time to union.

Prescribing considerations

Overprescribing opioids—A study published in JBJS (online) found that opioids may be commonly overprescribed after nonoperative fracture and dislocation treatments. Researchers analyzed 1,513 consecutive patients in China who underwent nonsurgical fracture and/or dislocation treatment and were prescribed opioids. Over three months, they observed opioid use, alcohol consumption, smoking status, injury location, volume of prescriptions, and consumption patterns. The mean number of pills prescribed was 14.7, and patients reported using an average of 7.2 pills. Ten percent of patients (n = 152) used no opioids, whereas 61.1 percent (n = 923) did not finish their opioid prescriptions. Location of injury, alcohol consumption, and type of injury were significantly associated with opioid use. Patients with injuries to the wrist, forearm, ankle, tibia, fibula, elbow, and humerus consumed more opioids, on average, than those with other injuries. Opioid use was higher among those with increased alcohol consumption and displaced fractures. The researchers recommend that surgeons avoid prescribing opioids to this patient population.

DMARDs for OA—Disease-modifying antirheumatic drugs (DMARDs) did not offer clinically significant pain relief compared to placebo for patients with OA, according to a study published in the journal Rheumatology (online). Researchers reviewed Medline, Embase, Allied and Complementary Medicine Database, Web of Science, and Cochrane Library, as well as conference abstracts and ClinicalTrials.gov information, to identify randomized, controlled trials (RCTs) of DMARDs and placebo for symptomatic OA published through November 2017. They included 11 RCTs with 1,205 participants, including six with conventional DMARDs (n = 757) and five with biologics (n = 448). DMARDs were statistically superior to placebo but not clinically significant. The researchers did not observe statistically significant differences in subanalysis of high-quality trials, biologics, or conventional DMARDs.

Perioperative ketorolac—Perioperative use of ketorolac may yield high rates of fracture union, according to a retrospective study published in Foot & Ankle International (online). Researchers assessed patients who received perioperative ketorolac for lateral malleolar, bimalleolar, and trimalleolar open reduction and internal fixation (ORIF) by the same surgeon between 2010 and 2016, with a minimum follow-up of four months. Patients were given 20 tabs of 10 mg ketorolac every six hours. Two orthopaedic foot and ankle surgeons assessed radiographs for healing. Of the 281 patients, 94 percent (n = 265) were deemed clinically healed within 12 weeks, and 92 percent (n = 261) were deemed radiographically healed. Among patients who did not heal by 12 weeks, the mean time to clinical healing was 16.9 weeks, whereas the mean time to radiographic healing was 17.1 weeks. In patients who received ketorolac, no cases of nonunion occurred and no significant difference was found between fracture patterns and healing or complications. The researchers said, “Additional studies are necessary to determine whether ketorolac helps reduce opioid consumption and improves pain following ORIF of ankle fractures.”

Underdosing prophylactic antibiotics—A study published in the Journal of Orthopaedic Trauma (July) found that a third of patients with open tibial fractures (n = 21) were underdosed with cefazolin at the time of initial presentation, and that this underdosing may lead to infection. Researchers included 63 adult patients from a Level I trauma center who had high-grade open extra-articular tibial fractures. Among the 20 patients who subsequently developed deep infection, 55 percent were appropriately dosed with cefazolin. Of the patients who did not develop deep infection, 72 percent received an appropriate antibiotic dose. Appropriate weight-based dosing (defined as at least 1 g for patients < 80 kg, 2 g for patients 80–120 kg, and 3 g for patients > 120 kg) of cefazolin for prophylaxis in high-grade open tibial fractures reduces the frequency of infection due to cefazolin-sensitive organisms.

Adalimumab for axial spondyloarthritis—Patients with non­radiographic axial spondyloarthritis who maintained remission with adalimumab may benefit from continued therapy, according to a study published in The Lancet (online). The multicenter, randomized, double-blind, two-period study was conducted at 107 sites in 20 countries between June 27, 2013, and Oct. 22, 2015. Researchers enrolled 673 adult patients with nonradiographic axial spondyloarthritis who met Assessment of SpondyloArthritis International Society classification material but not modified New York radiologic criterion. Patients showed active inflammation, disease, and no response to at least two nonsteroidal anti-inflammatory drugs. Patients who received adalimumab 40 mg every other week for 28 weeks and had inactive disease (n = 305, 45 percent) were randomized 1:1 to either continue adalimumab (n = 152) or receive placebo (n = 153). A greater proportion of patients who continued adalimumab did not experience a flare up to and including week 68. Among all patients who received adalimumab at any time, 516 (77 percent) reported an adverse event (AE). The most common AEs in both the adalimumab and placebo groups were nasopharyngitis, upper respiratory tract infection, and worsening of axial spondyloarthritis.

Spine

Repeat MRIs—According to a study published in The Spine Journal (online), repeated preoperative MRI may not show significant differences in cases of lumbar stenosis. The retrospective chart review examined stenosis patients who underwent lumbar decompression without fusion at a single institution between 2011 and 2015. Patients had at least two lumbar MRIs prior to surgery. At each pathologic disk level, researchers calculated the absolute value of the change in grade for central/lateral recess stenosis, right foraminal stenosis, and left foraminal stenosis from preoperative to repeated MRI. Of the 103 patients included, 37 had more than one lumbar level surgically addressed; 161 lumbar levels were reviewed. Among those who had any change in stenosis grade, most were mild changes of one (36 of 42 patients, 85.7 percent). Two patients displayed a moderate grade change of two, and one patient showed a severe grade change of three.

Surgically treated idiopathic scoliosis—Implant density does not always impact patient-reported outcomes when surgically treating idiopathic scoliosis, according to a retrospective study published in The Bone & Joint Journal (online). Researchers identified 328 patients aged 10–20 years at the time of surgery from the Swedish spine register (Swespine). Patients were classified as low density (mean number of implants per operated vertebra = 1.36), medium density (1.65), and high density (1.91). Reoperation and curve correction rates and the Scoliosis Research Society (SRS) 22r total score did not differ significantly among the groups. Researchers noted marginal differences in the SRS 22r domains: The medium-density group reported a higher level of self-image and the high-density group had a greater satisfaction rate. They concluded there was no advantage in using a high number of implants per operated vertebra in this patient population.

Bone health

BMD screening—A new genetic screening process may determine the risk for bone fracture and osteoporosis, according to a study published in PLOS One (online). Researchers used data from the U.K. Biobank to create an algorithm that identified 1,362 independent single nucleotide polymorphisms that clustered into 899 loci associated with low bone mineral density (BMD), 613 of which had not been identified previously. The algorithm also was capable of assigning each of the participants a score indicating risk for low BMD. Patients at high risk (2.2 percent of those tested) were 17 times more likely to develop osteoporosis and almost twice as likely to sustain a bone fracture. The researchers noted that early identification of those with an increased genetic risk for osteoporosis could help prevent or reduce the incidence of bone fracture.

Grafts from bone segments—A new technique developed by scientists from the New York Stem Cell Foundation enables researchers to combine bone segments made with stem cells to create personalized grafts for patients with bone disease or injury, according to a paper published in Scientific Reports (online). The technique, called Segmental Additive Tissue Engineering (SATE), was used to reconstruct a femoral defect in a rabbit via transverse partitioning to the longitudinal axis to allow effective tissue formation in vitro. A digital model of the rabbit femur was created and used to isolate 14 segments with a thickness of 0.5 cm that were patched to create 3D-printed inserts. The SATE technique allows for reproducible and effective segmental bone graft engineering for personalized reconstructive procedures, according to the researchers.