Published 12/1/2017

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
Perioperative morbidity—Data published in JAMA Surgery (online) suggest that frailty may be independently associated with perioperative morbidity in patients undergoing common ambulatory general surgery. The authors conducted a retrospective, cohort study of 140,828 patients aged older than 40 years, who underwent one of four ambulatory general surgeries. Of those, 2,457 (1.7 percent) experienced a perioperative complication and 971 (0.7 percent) experienced a serious perioperative complication. The authors note that an increasing modified frailty index was associated with a stepwise increase in the occurrence of complications.

Biofilms—A study published in the Journal of Orthopaedic Research (online) suggests that use of a flash autoclave may not remove the presence of biofilms from titanium surfaces. The researchers grew monomicrobial and polymicrobial biofilms on the surface of orthopaedic-relevant titanium materials and exposed them to flash autoclave settings of varying times and temperatures. The authors found that when the sterilization and control temperatures of an autoclave were the same, biofilms could survive a short duration of flash autoclaving. Although higher temperature and increased duration rendered biofilms nonviable, none of the autoclave settings demonstrated the ability to disperse the presence of biofilms from surfaces.

MOM cardiotoxicity—A study published in The Journal of Bone & Joint Surgery (JBJS; Nov. 1) suggests that high (but not extreme) blood cobalt and chromium levels may not be associated with a significant cardiotoxic effect on patients with a metal-on-metal (MOM) hip implant. The research team conducted a prospective, blinded study of 90 patients assigned to three age- and sex-matched cohorts: ceramic-on-ceramic, MOM with low whole-blood metal ion levels, and MOM with high whole-blood metal ion levels. Members of the research team noted that blood cobalt levels differed significantly across cohorts. However, they found no significant differences across cohorts in left atrial or ventricle size, ejection fraction, T1 or T2 values, extracellular volume, B-type natriuretic peptide level, or troponin level, and all values were within normal ranges. In addition, they observed no relationship between cobalt levels and ejection fraction, even at extremes, suggesting no clinically important association.

SSI—Data published in Clinical Infectious Diseases (online) suggest that patients with a reported penicillin allergy may have a 50 percent increased chance of contracting a surgical site infection (SSI). The researchers conducted a retrospective cohort study of 8,385 patients who had undergone 9,004 surgical procedures, including hip arthroplasty or knee arthroplasty, and found that SSI developed in 241 patients (2.7 percent) of whom 3.5 percent reported a penicillin allergy and 2.6 percent reported no allergy. Patients with a documented penicillin allergy received less- effective antibiotics, including clindamycin, vancomycin, and gentamicin. The authors note that most patients with a documented penicillin allergy may not be allergic.

Racial disparities—Data presented at the annual meeting of the American College of Rheumatology (ACR) suggest racial disparity in outcomes for total hip arthroplasty (THA) patients. The researchers reviewed data on 4,170 patients from an institutional THA registry and found that, at baseline and 2-year follow-up, black patients had worse Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores compared to white patients. They note that disparities were increased in communities with a high percentage of Medicaid patients; among black patients in such communities, 2-year WOMAC function scores were on average 5.54 points lower than among black patients from communities with a low prevalence of Medicaid coverage. Scores for white patients did not differ significantly between communities.

TXA—Two studies in the Journal of Orthopaedic Trauma (October) examine the use of tranexamic acid (TXA) in fracture surgery. In the first, the researchers conducted a prospective, randomized trial of 88 patients who underwent acetabular fracture surgery and who were treated with TXA (n = 42) or placebo (n = 46). They found no significant difference across cohorts in transfusion rate, estimated blood loss, or incidence of venous thromboembolism. The researchers suggest that the benefits of TXA may be "overwhelmed by other factors, specifically preoperative anemia and surgical time, which are highly variable in trauma surgery."

In the second study, members of the research team conducted a meta-analysis of seven studies and 559 patients who underwent surgical fracture repair. Compared with placebo, they found that use of TXA in fracture surgery was associated with significantly reduced total blood loss, reduced transfusion rate, and decreased hemoglobin drop. They found no significant difference in number of thromboembolic events across groups.

PSH model—Use of a perioperative surgical home (PSH) model of care may help improve outcomes for older patients who undergo surgical repair for hip fracture, according to information presented at the annual meeting of the American Society of Anesthesiologists. The researchers compared outcomes for 222 patients treated prior to implementation of a PSH model and 118 patients treated after, and found that 3.2 percent of non-PSH patients died within 30 days of discharge, compared to zero PSH patients. After 90 days, 6.3 percent of non-PSH patients had died, compared to 2.5 percent of PSH patients. In addition, the researchers found that PSH patients were less likely than non-PSH patients to return to the emergency department within 90 days (14.4 percent vs. 23.4 percent), less likely to be readmitted within 90 days (17.8 percent vs. 23.9 percent), and more likely to be discharged to home instead of a nursing facility (40.7 percent vs. 16.2 percent).

Stress injuries—A study in the British Journal of Sports Medicine (online) looks at factors linked to stress injuries among Olympic athletes. The researchers reviewed information on all sports injuries at the Rio de Janeiro 2016 Summer Olympics reported by National Olympic Committee (NOC) medical teams and in the polyclinic and medical venues. Overall, 1,101 injuries were reported across 11,274 athletes from 207 NOCs. Digital radiography and MRI revealed nine stress fractures and 16 stress reactions. The researchers note that stress injuries were most common in the lower extremities (84 percent), particularly tibia (44 percent) and metatarsals (12 percent), with two in the lumbar spine (8 percent). In addition, stress injuries were most common in track and field athletes (44 percent) followed by volleyball players (16 percent), and artistic gymnastics (12 percent). They write that the data demonstrate the importance of early imaging with MRI to detect stress reactions before they can progress to stress fractures.

Bisphosphonates—A study presented at the ACR annual meeting suggests that a bisphosphonate "drug holiday" of more than 2 years may be associated with significantly increased risk of hip fracture among older women treated with bisphosphonates and who were at least 80 percent adherent for 2 or more years. The researchers reviewed Medicare data of 156,236 women with a mean age of 78.5 years. During a median follow up of 2.1 years, 40.1 percent (n = 62,676) of patients stopped bisphosphonate therapy for at least 6 months. Overall, 3,745 hip fractures occurred during follow-up. The researchers noted that hip fracture rates were lowest among women who were current users, and gradually increased as the length of the drug holiday increased, achieving their maximum with a drug holiday of longer than 2 years.

Hip and knee
Arthroscopic labral repair—A study in The American Journal of Sports Medicine (AJSM; online) looks at mid-term outcomes for patients who have undergone primary hip arthroscopic labral repair. The authors conducted a cohort study of 303 patients (mean age 32 years). At mean 5.7-year follow-up, they found overall mean improvement in visual analog scale of 3.5 points, modified Harris Hip Score (mHHS) of 20.1 points, and Hip Outcome Score–Sports-Specific Subscale (HOS-SSS) of 29.3 points. The authors note that preoperative Tönnis grade 2 change, body mass index >30 kg/m2, and age >35 years at time of surgery were associated with significantly decreased mHHS and HOS-SSS scores at final follow-up. Overall, 37 patients (12.2 percent) underwent revision arthroscopic surgery, and 12 (4.0 percent) underwent periacetabular osteotomy, resurfacing, or total hip arthroplasty during the study period.

XLPE liners—According to a study in JBJS (Oct. 18), use of highly cross-linked polyethylene (XLPE) liners may be associated with greater implant survival rates compared to conventional bearing surfaces for THA patients. The authors conducted a prospective, double-blind, randomized, controlled trial of 91 patients who received implants with either conventional ultra-high molecular weight polyethylene (UHMWPE) bearing surfaces or an XLPE liner. At 10-year follow-up, they found that 3-dimensional wear rates were significantly lower in the XLPE cohort compared to the UHMWPE cohort. In addition, prevalence of osteolysis and revision rates were also significantly lower in the XLPE group compared to the UHMWPE. The authors noted no significant difference in the clinical scores across cohorts.

Multimodal analgesia—A study in JBJS (Nov. 1) compares the use of peripheral nerve blockade (PNB) against two variations of periarticular infiltration (PAI) as part of a multimodal analgesia pathway for THA. The authors conducted a randomized clinical trial of 159 patients who underwent THA and who received either PNB (n = 51), PAI with ropivacaine, ketorolac, and epinephrine (PAI-R; n = 54), or PAI with liposomal bupivacaine, ketorolac, and epinephrine (PAI-L; n = 54). They found that opioid consumption was low and did not differ across cohorts at any time interval. However, based on a 1-10 ascending numeric rating scale, median maximum pain on postoperative day 1 was 5.0 in the PNB group, 5.5 in the PAI-R group, and 4.0 in the PAI-L group. On postoperative day 2, median maximum pain was 3.5 for the PNB group, 5.0 for the PAI-R group, and 3.5 for the PAI-L group. The authors write that the PAI-L group was not significantly different from the PNB group with respect to postoperative opioid use, length of stay, hospital adverse events, and 3-month follow-up data including any complication.

Minimal incision THA—Data published in JBJS (Oct 18) suggest that minimal incision THA performed by a high-volume surgeon may offer little long-term benefit over a standard incision approach. The authors reviewed outcome scores (n = 152) and radiographs (n = 126) at 10-year follow-up for patients who participated in a prospective, randomized, controlled trial that compared standard incision THA against minimal incision THA. They found no significant difference in functional status or radiographic outcome across cohorts. The authors note that 10-year implant survival rate was 99.1 percent in the standard incision group and 97.9 percent in the minimal incision group.

TXA—Findings in JBJS (Oct. 4) suggest that epsilon-aminocaproic acid (EACA) may be an acceptable alternative to TXA for blood conservation following total knee arthroplasty (TKA). The authors conducted a prospective, randomized, controlled trial of 194 TKA patients, of whom 96 received EACA and 98 received TXA. They note that, although the estimated blood loss was significantly greater in the EACA cohort, no transfusions were required in either group and no significant differences were noted in change in hemoglobin or serum creatinine level, postoperative complications, or length of hospital stay.

Shoulder and elbow
Rotator cuff tear—According to a study in the Journal of Shoulder and Elbow Surgery (online), negative T-scale value may predict poorer clinical outcomes and higher retear rates for certain patients with full-thickness rotator cuff tears. The researchers reviewed data on 120 consecutive patients undergoing primary rotator cuff repair and found that preoperative T-scale correlated significantly with postoperative forward elevation and clinical scores for patients with large to massive tears but not among patients with small to medium tears. Overall, the relative risk of retear was 2.0 to 7.9 times greater for patients with negative T-scale values.

Medial elbow injury—Data presented in AJSM (online) suggest that use of an exercise program to improve physical function can help reduce the likelihood of medial elbow injury in youth baseball players. The researchers conducted a cohort study of 305 baseball players, aged 8 to 11 years, with no history of elbow or shoulder pain. Overall, 136 were assigned to an intervention cohort and 169 received no intervention. Intervention consisted of nine strengthening and nine stretching exercises, performed during warm-up or at home, with high compliance defined as completion of the program one or more times per week. At 1-year follow-up, the researchers found that the incidence rate of medial elbow injury was significantly lower in the intervention group compared to the control group. In addition, the intervention program was associated with improved total range of shoulder rotation (dominant side), hip internal rotation (nondominant side), shoulder internal rotation deficit (bilaterally), lower trapezius muscle strength (dominant side), and the thoracic kyphosis angle.

VTE prophylaxis—Data from a study in The Spine Journal (online) suggest that pharmacologic prophylaxis may not significantly reduce venous thromboembolism (VTE) following spine surgery, but may increase other risks. The authors conducted a retrospective, cohort study of elective spine surgery patients that included 109,609 participants in the National Surgical Quality Improvement Program database and 2,855 patients treated at a single institution. They found that independent risk factors for VTE included increasing age, male sex, increasing body mass index, dependent functional status, lumbar spine surgery, longer surgical time, perioperative blood transfusion, longer length of stay, and other postoperative complications. Among the institutional patients, 56.3 percent received pharmacologic VTE prophylaxis and of those, 97.1 percent received unfractionated heparin. The authors found no significant reduction in VTE across cohorts but noted a significant increase in postoperative hematoma requiring reoperation among patients receiving prophylaxis.

Foot and ankle
Achilles tendon rupture—Data published in Foot & Ankle International (online) suggest no significant difference in Achilles tendon total rupture score (ATRS) for patients treated surgically or nonsurgically. The researchers analyzed 132 patients (62 surgical, 70 nonsurgical) with minimum 2-year follow-up. They found no significant difference in ATRS between the surgical and nonsurgical management cohorts (mean 84.8 and 85.3, median 90 and 91, respectively) with identical rehabilitation programs of functional bracing. They also noted no significant difference in ATRS across treatment cohorts based on patient sex or age at time of injury.

Pain relief—Data published in the Canadian Medical Association Journal (October) suggest that ibuprofen may be preferred to morphine for pain relief in pediatric patients who have undergone minor outpatient orthopaedic surgery. The authors conducted a randomized controlled trial of 132 children aged 5 to 17 years, of whom 65 received morphine and 67 received ibuprofen. They found no significant difference in pain score across cohorts. However, they noted adverse events in 45 (69 percent) of patients given morphine and 26 (39 percent) of patients given ibuprofen.

Acute knee injury—A study in the Orthopaedic Journal of Sports Medicine (online) suggests that clinicians who evaluate younger athletes with acute knee injury should be careful not to overlook possible intra-articular physeal fracture. The authors conducted a retrospective review of 49 patients aged 7 to 17 years who presented with intra-articular physeal fracture at one of three high-volume pediatric centers. They found that the initial diagnosis was missed in 39 percent of cases. The authors note that football was responsible for 50 percent of all injuries. Overall, 84 percent of fractures were Salter-Harris type III fractures, and of those, 88 percent involved the medial femoral condyle.