Published 2/1/2016

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)

Basic science
MSC therapy
—A lab animal study published in Molecular Therapy (online) suggests that parathyroid hormone (PTH) injections may complement intravenous mesenchymal stem cell (MSC) therapy in inducing fracture repair. The researchers used a rat model of osteoporotic vertebral bone defects to evaluate the efficacy of combination intravenous MSC and PTH therapy versus monotherapy and untreated controls. At 2-week follow-up, they found that the combination therapy was associated with significantly increased new bone formation versus monotherapy and control cohorts. The researchers noted that PTH significantly enhanced MSC migration to the lumbar region, where MSCs differentiated into bone-forming cells.

PRP—Data from a study published online in the journal Foot & Ankle International (online) suggest that intraoperative application of platelet-rich plasma (PRP) may not reduce the likelihood of postoperative infection or delayed wound healing (DWH). The authors conducted a prospective, randomized trial of 500 patients undergoing foot or ankle surgery; patients were randomized to receive intraoperative PRP (applied to operative field) and platelet-poor plasma at closing (PPP, on the sutured skin) or to serve as controls. Of the 250 patients in the control group, 70 had blood drawn and PRP prepared for later assay of growth factors. Deep surgical site infections were noted in two patients in the experimental cohort and in one patient in the control cohort, while DWH was noted in 17 patients in the experimental group and in 17 patients in the control group.

Débridement—Data from a study published in the Journal of Orthopaedic Trauma (JOT, January) suggest that the so-called "4 Cs" (muscle color, consistency, contractility, and capacity to bleed) may not correlate with histologic findings regarding muscle viability when débridement is performed. The authors collected 36 biopsies from 20 patients who had undergone débridement for open fracture (81 percent), compartment syndrome (11 percent), infection (5 percent), or crush injury (3 percent). Surgeons graded the biopsies using the 4 Cs and provided their overall impression as healthy, borderline, or dead, and a blinded pathologic analysis was performed on each specimen. The authors note that surgeons evaluated dead muscle in 25 specimens, borderline in 10, and healthy in 1. However, a pathologic analysis of the 35 specimens considered by surgeons to be dead or borderline muscle demonstrated normal muscle or mild interstitial inflammation in 21 specimens (60 percent). In 72 percent of specimens, the treating surgeon's gross assessment differed from the histopathologic appearance. The authors write that, although the fate of the débrided muscle remained unclear if left in situ, the results suggest that surgeons may sometimes débride potentially viable muscle.

Tibial shaft fracture—
According to data published in JOT (online), reaming may not affect functional outcomes following intramedullary (IM) nailing for tibial shaft fractures. The researchers conducted a prospective, randomized, controlled trial of 1,319 skeletally mature patients with closed and open diaphyseal tibia fractures who were randomized to treatment with either reamed or unreamed nails. At 12-month follow-up, they found no difference between cohorts in SF-36 Physical Component Score (PCS) or Short Musculoskeletal Function Assessment (SFMA) Dysfunction Index. The researchers also noted that at 12-months, neither cohort had achieved baseline function on the SF-36 PCS, SMFA Dysfunction Index, or SMFA Bothersome Index.

Vitamin D—Data published in The Journal of Foot & Ankle Surgery (online) suggest that reduced levels of vitamin D may be associated with an increased risk of stress fracture for active individuals. The researchers conducted a retrospective, cohort study of 53 patients who had vitamin D levels measured within 3 months of a confirmed diagnosis of stress fracture. They found that 83 percent (n = 44) had a serum 25-hydroxyvitamin D level of less than 40 ng/mL. Based on standards recommended by the Vitamin D Council, the researchers note that more than 80 percent of the patients would be classified as having insufficient or deficient vitamin D levels. Based on standards set by the Endocrine Society, more than 50 percent had insufficient levels.

Body pain—According to a study conducted in the United Kingdom and published in Archives of Osteoporosis (online), previous fracture may be associated with an increased likelihood of chronic widespread bodily pain (CWBP). The authors drew data on 501,733 participants (mean age 56.5 years) in the UK Biobank cohort. Overall, 7,130 individuals reported CWBP and 23,177 had a history of fracture affecting the upper limb, lower limb, spine, or hip. The authors found that those with prior fracture were significantly more likely to report CWBP than those without. After adjustment, they found that risk ratios were attenuated but still statistically significant, with a risk ratio of 2.67 for CWBP with spine fractures in men and 2.13 for CWBP with spine fractures in women, and a risk ratio of 2.19 for CWBP with hip fractures in women.

ACL repair—
Findings published in The American Journal of Sports Medicine (online) suggest that age at the time of anterior cruciate ligament reconstruction (ACLR) may be a strong risk factor for revision. The researchers conducted a case-control study of 21,304 patients who underwent primary ACLR, with patients stratified by age into four groups: < 21, 21-30, 31-40, and > 40 years. They found that the 5-year revision probability was highest among patients in the < 21 years cohort and lowest in the > 40 years old cohort. Among patients age younger than 21 years, the researchers noted a lower risk of revision in female patients, patients with increased body mass index (BMI), and black patients compared to white patients. Sex, BMI, and race were not associated with the risk of revision in older patients. Among patients ≤ 40 years old, those with allografts had a higher risk of revision than those with bone-patellar tendon-bone (BPTB) autografts. However, patients < 21 years old with hamstring autografts had a higher risk of revision than did patients with BPTB autografts.

Hyaluronic acid—Data published in the Dec. 16 issue of The Journal of Bone & Joint Surgery (JBJS, Dec. 16) suggest that when only the best-quality evidence is considered, viscosupplementation with hyaluronic acid (HA) injection may offer little clinical benefit compared to placebo for patients with knee osteoarthritis (OA). The researchers conducted a "best-evidence" systematic review and meta-analysis of 19 trials. In a meta-analysis of only double-blinded, sham-controlled trials of at least 60 patients, the researchers found no clinically important differences of HA treatment over placebo. When all literature was added to the analysis, the overall effect was greater, but biased toward stronger treatment effects due to the influence of nonblinded or improperly blinded trials.

Surgeon case loads—Findings from a study conducted in the United Kingdom and published in JBJS (Jan. 6) suggest that surgeons who perform higher caseloads of unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) procedures may be associated with reduced rates of revision. The research team reviewed 459,280 patient records (37,131 UKAs and 422,149 TKAs) from the National Joint Registry for England and Wales. They found that, for surgeons who performed fewer than 10 UKAs per year, the mean 8-year rate of implant survival was 87.9 percent, compared with 92.4 percent for those who performed 30 or more UKAs per year. The research team did note that surgeons who performed a lower volume of UKAs tended to operate on younger and healthier patients, and were more likely to perform revisions to treat loosening and pain. In addition, an analysis of TKAs displayed a linear decrease in revision rate as caseload increased.

MCL repair—Data published in JBJS (Jan. 6) suggest that intraoperative medial collateral ligament (MCL) injury can be treated with primary repair followed by hinged knee bracing without the need for increased prosthetic constraint. The authors conducted a retrospective review of 3,922 TKAs, of which 48 (1.2 percent) were associated with intraoperative MCL injury, of which 45 were available for study. Midsubstance lacerations were treated with end-to-end suture repair, and a screw-and-washer construct, suture, and/or suture anchors were used for reattachment of avulsions. In addition, all patients were instructed to wear an unlocked hinged knee brace for 6 weeks postoperatively. Overall, there were 24 midsubstance lacerations and 21 avulsions, 35 of which occurred during a cruciate-retaining TKA and 10 of which occurred during a posterior-stabilized TKA. At mean 99-month follow-up, the authors found no symptoms or physical examination findings of instability, and the mean Hospital for Special Surgery knee score had increased from 47 preoperatively to 85. However, five knees required intervention for stiffness and two required revision for aseptic loosening.

Findings from a study published in JBJS (Dec. 2) suggest that patients who have undergone percutaneous in situ fixation for stable slipped capital femoral epiphysis (SCFE) may self-report their health as poor compared to the general population. The research team conducted a retrospective study of 64 patients (91 hips) with SCFE. At mean 19.6-year follow-up, they found that the cohort reported higher rates of diabetes, obesity, and hypertension than the general U.S. population. In addition, mean BMI had increased by 10.2 kg/m2, with 72 percent of patients meeting the criteria for obesity at the time of follow-up.

FAI—A study published in JBJS (Dec. 16) finds that administration of naproxen following arthroscopic surgery for femoroacetabular impingement (FAI) was effective in reducing the prevalence of heterotopic ossification (HO) without medication-related morbidity. Patients in the study were randomized preoperatively on the day of their surgery to take either naproxen (500 mg) or a placebo twice daily for 3 weeks following surgery. The final prevalence of HO in FAI patients randomized to the naproxen group was 4 percent (2 of 48) versus 46 percent (22 of 48) in the patients randomized to the placebo group. Although the authors concluded that prophylactic naproxen therapy significantly reduces the prevalence of HO after hip arthroscopy, they noted, "It still remains to be determined which NSAID and dosing schedule are ideal for HO prophylaxis in this patient population."

Bearing surfaces—According to findings published in Clinical Orthopaedics and Related Research (CORR, December), ceramic bearing surfaces may be linked to lower likelihood of dislocation after revision total hip arthroplasty (THA) compared to polyethylene bearing surfaces. The authors reviewed information on 240 patients (240 hips) who had a THA revision and a normal contralateral hip. They found that 18 percent (29 of 160) of polyethylene liners at the time of index arthroplasty dislocated after revision, compared to 1 percent (1 of 80) of ceramic liners. Among the 80 hips with ceramic-on-ceramic surfaces, no osteolysis was detected before revision, and no muscle fatty degeneration of the gluteus muscles was noted on computed tomography (CT) scan or histology. However, the authors observed osteolytic lesions on the acetabulum and femur in 100 percent of hips with polyethylene liners. They noted that increased atrophy of the gluteus muscles observed on CT scan correlated with an increase of osteolysis.

Alternative bearings—Findings from a study published in CORR (December) suggest that use of alternative bearings or modularity have not resulted in decreased revision rates for THA after 5 years. The researchers conducted a systematic review of 32 studies and 5 registry reports on metal-on-metal implants, 19 studies and 5 registry reports on ceramic-on-ceramic implants, and 20 studies and 1 registry report on modular stem designs. They excluded metal-on-ceramic and ceramic-on-metal implants from evaluation due to insufficient data, and did not evaluate monoblock acetabular designs due to their inclusion in another recent systematic review. The researchers found no published evidence that alternative bearings (either metal-on-metal or ceramic-on-ceramic) were associated with decreased revision rates after THA. However, they noted that registry data demonstrate that large head metal-on-metal implants had lower 7- to 10-year survivorship compared to standard bearings, and that modular exchangeable femoral neck implants had a lower 10-year survival rate in both literature reviews and in registry data compared with combined registry primary THA implant survivorship.

The authors of a review study published in the European Journal of Endocrinology (online) argue that, because onset of type 1 diabetes mellitus (T1DM) often occurs during childhood, the bone health of at-risk children should be assessed and managed. They note that patients with T1DM often have impaired osteoblastic bone formation, with insulin/IGF-1 deficiency, glucose toxicity, marrow adiposity, inflammation, adipokine and other metabolic alterations being pathogenetic mechanisms. Among other things, they write that "increasing physical activity in children with diabetes as well as good glycemic control appear to provide some improvement of bone parameters, although robust clinical studies are still lacking. In this context, the role of osteoporosis drugs remains unknown."

Radial neck fracture—According to a study published in the Journal of Pediatric Orthopaedics (January), older children are more likely than younger children to have more severely displaced radial neck fractures that require open surgical management, placing them at greater risk of fair or poor outcomes. The authors evaluated data on 193 consecutive children with a radial neck fracture who were seen at a single level 1 trauma center and who had satisfactory initial treatment data and follow-up range-of-motion (ROM) data. Patients treated nonsurgically were of a younger average age than those in the surgical group. Overall, 13 percent of patients required surgical treatment (average age 9.1 years). Those who required open management were an average of 10 years old and had a significantly greater risk of a fair or poor ROM outcome than those treated with closed techniques. Patients treated surgically were more likely to experience complications, but the authors found that presence of a complication was not predictive of fair or poor outcomes in either the surgical or nonsurgical groups.

Adolescent idiopathic scoliosis—Study data published in JBJS (Dec. 16) indicate that ScoliScore values do not differ among patients with adolescent idiopathic scoliosis (AIS) patients regardless of curve progression. When administered in the early stages of AIS development, the ScoliScore saliva test is designed to predict the potential for curve progression in AIS patients. Researchers administered ScolioScore tests to 126 skeletally immature AIS patients (89 percent female; mean age = 12 years) at two institutions between Jan. 1, 2009, and June 21, 2012, and followed the patients until they reached skeletal maturity. The researchers identified two outcome groups: progression and nonprogression. Patients in the progression group either had a Cobb angle > 40° or had undergone surgical fusion; patients in the nonprogression group had reached skeletal maturity without curve progression to > 40°. The researchers found no significant difference in the mean ScoliScore between patients with and without curve progression. They also found no significant difference in curve progression between patients with high-risk ScoliScore values and those with low-risk values.

Compliance—Data from a study published in JBJS (Jan. 6) suggest that providing compliance feedback regarding brace wear may improve compliance for patients who undergo bracing for adolescent idiopathic scoliosis. The research team conducted a prospective study of 171 patients who were counseled with the use of compliance data (n = 93) or not counseled (n = 78). They found that patients in the counseled group wore their orthoses an average of 13.8 hours per day throughout their management, while noncounseled patients wore their braces an average of 10.8 hours per day. Of patients in the counseling cohort who finished brace treatment, 59 percent did not have curve progression of ≥ 6° and 25 percent had progression to ≥ 50° or to surgery. Among patients in the noncounseled cohort, 46 percent did not have curve progression of ≥ 6° and 36 percent had progression to ≥ 50° or to surgery. There was a nonsignificant difference in average curve magnitude between cohorts at initiation of bracing.

Rotator cuff—
Findings from a study published in the Journal of Shoulder and Elbow Surgery (online) suggest that questionnaires regarding patient function and isokinetic strength evaluation may offer little efficacy in determining early postoperative repair status after rotator cuff repair. The authors prospectively evaluated 60 patients who had undergone arthroscopic supraspinatus repair. At 16-week follow-up, they found no significant correlation between clinical or strength measures in predicting intact repairs (Sugaya grade 1) or partial-thickness retears (Sugaya grades 2 and 3). The authors note that discriminant analysis revealed the 11-item version of the Disabilities of the Arm, Shoulder and Hand produced a 97 percent true-positive rate for predicting partial thickness retears, but also produced a 90 percent false-positive rate, predicting retear in 90 percent of patients whose repair was intact. Further, they state that the ability to discriminate between groups was enhanced with up to 5 variables entered, yet only 87 percent of the partial-retear group and 36 percent of the intact-repair group were correctly classified.

Data from a study conducted in Thailand and published in Spine (December) suggest that treatment with two effective doses of tranexamic acid (TXA) may reduce blood loss and transfusions for low-risk adults who undergo complex spine surgery. The research team conducted a prospective, double-blind, randomized controlled study of 78 adult patients at a single center. One cohort (n = 39) received saline or placebo, while a second cohort (n = 39) received two doses (15 mg/kg) of TXA—one prior to anesthesia induction and the second after 3 hours. They found that blood loss was higher in the control group than in the TXA group. In addition, patients in the control group received more crystalloid, colloid, and packed red blood cell transfusions. There were no serious thromboembolic complications.

Injury patterns—
A report published in the U.S. Centers for Disease Control and Prevention (CDC) Morbidity and Mortality Weekly Report looks at patterns in college sports-related injuries over a 5-year period. Across 25 collegiate sports, the report finds an estimated 28,860,299 practice athlete-exposures and 6,472,952 competition athlete-exposures occurred each year. The 1,053,370 injuries estimated from the 2009–2010 through 2013–2014 academic years represented an average of 210,674 total injuries per year, of which 134,498 (63.8 percent) occurred during practices. The report finds that approximately half of all injuries were diagnosed as sprains or strains, which also accounted for the largest proportions of injuries in competition and practice requiring 7 or more days before return to full participation, and the largest proportion of injuries requiring surgery. The report also notes that during competition, the largest proportions of injuries requiring emergency transport were fractures, stress fractures, dislocations, subluxations, and concussions.