AAOS Now

Published 6/1/2016

Second Look – Clinical News and Views

Hand and wrist
Dupuytren disease—
Data from a study published in The Journal of Hand Surgery (online) suggest high satisfaction for patients with Dupuytren disease who are treated with collagenase clostridium histolyticum (CCH) injection. The research team conducted a cross-sectional study of 213 patients who had been treated for Dupuytren disease with CCH. They found that 73 percent of patients were very satisfied or satisfied, and 21 percent were dissatisfied. Overall, 75 percent said they would probably or definitely undergo CCH treatment again, and 17 percent probably or definitely would not. The research team found that satisfaction and willingness to undergo a second treatment decreased over time, and had a negative relationship with recurrence.

Hip and knee
Metal-on-metal—Findings published in The Journal of Bone & Joint Surgery (JBJS; April 20) suggest that a blood test may help identify patients who may be at risk of adverse reactions to metal debris associated with metal-on-metal (MOM) hip implants. The authors conducted a prospective study of 598 patients with unilateral hip implants that use one of two common designs. All patients underwent whole blood metal ion sampling at mean 6.9-year follow-up. Overall, 46 patients had adverse reactions to metal debris. All ion parameters were significantly higher in patients who had adverse reactions to metal debris.

UKA—According to a study published in JBJS (April 20), use of a robotic surgical arm may be associated with improved accuracy of implant positioning compared to conventional techniques for patients undergoing unicompartmental knee arthroplasty (UKA). The authors conducted a prospective, randomized, single-blind, controlled trial of 120 patients, 62 of whom underwent robotic-assisted UKA and 58 of whom underwent conventional UKA. At 3-month follow-up with computed tomography, they found that use of the robotic surgical arm was associated with improved component positioning accuracy, with lower root mean square errors and significantly lower median errors in all component parameters. Overall, the proportion of patients with component implantation within 2° of the target position was significantly greater in the robotic cohort compared to the conventional cohort, with regard to femoral component sagittal position, femoral component coronal position, femoral component axial position, tibial component sagittal position, and tibial component axial position.

Hip dysplasia—According to a study published in Clinical Orthopaedics and Related Research (CORR; online), cephalic presentation at birth and history of swaddling are risk factors for late-presenting developmental dysplasia of the hip (DDH) in infants. The researchers retrospectively reviewed prospectively collected data from a multicenter database on 392 infants aged 18 months or younger with DDH. Only infants with fully dislocated hips were included in the study. Patients were divided into two groups: early-presenting (< 3 months of age; n = 259) and late-presenting (3–18 months of age; n = 133). The researchers used univariate/multivariate analysis to compare baseline demographics between the groups. Late-presenting patients were more likely to have had a cephalic presentation than early-presenting patients (88 percent versus 65 percent). Late-presenting patients were also more likely than early-presenting patients to have had a history of swaddling (40 percent versus 25 percent).

Shoulder and elbow
Distal radius fixation—Pain control during the immediate perioperative period in patients undergoing surgical fixation for distal radius fracture was not significantly different in those receiving brachial plexus blockade versus those receiving general anesthesia, according to a study in CORR (May). However, the patients who received a brachial plexus blockade did experience an increase in pain 12 to 24 hours after surgery. The authors of the randomized control trial involving a final group of 36 patients write that "acknowledging 'rebound pain' after the use of regional anesthesia coupled with patient counseling regarding early narcotic administration may allow patients to have more effective postoperative pain control."

Proximal humeral fracture—Findings published in the Journal of Shoulder and Elbow Surgery (May) suggest that use of locking plates or locking intramedullary nails yields similar outcomes in patients with proximal humeral fracture (PHF), although nails may be associated with increased complication rates. The research team conducted a prospective, randomized, controlled trial of 72 patients with 2- or 3-part surgical neck PHFs who underwent fixation with locking intramedullary nails or locking plates. At 12-month follow-up, they found no significant mean difference between cohorts according to patients' Constant-Murley scores. In addition, there were no differences in the 3-, 6- and 12-month Disabilities of the Arm, Shoulder and Hand scores, visual analog scale scores, as well as range of motion, except for medial rotation at 6 months. In addition, neck-shaft angle was equivalent between the groups at 12 months. However, the research team found that total complication rate and reoperation rate were significantly greater in the nail cohort. There were no significant differences between cohorts in rotator cuff tear rate.

Radial head replacement—Patients who underwent treatment for radial head fractures with modular metallic radial head replacement had outcomes at a mean 8-year follow-up, with no evidence of functional deterioration, that were comparable to those previously reported in shorter-term studies, an article in JBJS (April 6) reports. The study's authors retrospectively reviewed the cases of 55 patients with unreconstructible radial head fractures who received the implants. The authors note that in the time since a longer-term outcomes study (mean of 12 years) for radial head replacement appeared in 2001, "important advances have been made in implant sizing, surgical technique, and our understanding of elbow biomechanics." They note that "radial head arthroplasty with a smooth-stemmed metallic modular implant is a good treatment option for patients with acute unreconstructible radial head fractures, and sustained clinical outcomes may be expected beyond 5 years of follow-up."

Spine
Spinal cord injury—Data from a study published online in the journal Nature suggest that, contrary to prevailing understanding, astrocyte scar formation may aid central nervous system axon regeneration. The authors conducted a mouse study to investigate the effects of treatment with growth factors on severe spinal cord injuries. They found that the treatment stimulated robust, laminin-dependent sensory axon regrowth. However, preventing astrocytic scar formation significantly reduced the stimulated axon regrowth.

Lumbar spinal stenosis—A study conducted in Sweden and published in The New England Journal of Medicine (April 14) suggests that, compared to decompression surgery alone, decompression with fusion did not result in superior clinical outcomes in patients with lumbar spinal stenosis, with or without degenerative spondylolisthesis. The researchers conducted a randomized, controlled trial of 228 patients between the ages of 50 and 80 years with lumbar spinal stenosis at one or two adjacent vertebral levels. Patients had been randomly assigned to receive either decompression surgery alone (n = 117) or decompression with fusion (n = 111). The primary outcome was the Oswestry Disability Index (ODI) score. The researchers found no significant difference in the mean ODI score between the two groups at 2-year follow-up. In addition, decompression plus fusion was associated with longer surgical times, more blood loss, and higher costs, compared to decompression alone.

Fracture
Fracture after TKA—Preliminary findings from a study conducted in Sweden and presented at the World Congress on Osteoporosis, Osteoarthritis and Musculoskeletal Diseases suggest that patients who undergo total knee arthroplasty (TKA) may be at increased risk for hip and vertebral fracture in the following decade. The research team reviewed medical records from the entire Swedish population born between 1902 and 1952. At 10-year follow-up after TKA, they found that risk of hip fracture increased 4 percent and risk of vertebral fracture increased 19 percent compared to members of the general population who did not undergo TKA. Risk of fracture was also increased for TKA patients compared to the 10-year period prior to undergoing TKA.

Osteoporotic fracture—According to research conducted in Iceland and presented at the World Congress on Osteoporosis, Osteoarthritis and Musculoskeletal Diseases, patients who experience a major osteoporotic fracture may be at greatest risk of a second major osteoporotic fracture immediately following the first fracture. The researchers reviewed data on 118,872 participants in the Reykjavik Study. They found that 5,039 patients experienced at least one major osteoporotic fracture, and of those, 1,919 experienced a second. The researchers found that risk of a second fracture remained elevated compared to the general population, but decreased over time, and was highest immediately after the first fracture.

Trabecular bone score—Findings published in the Journal of Bone and Mineral Research (online) suggest that trabecular bone score (TBS) may be a significant predictor of fracture risk independent of the Fracture Risk Assessment Tool (FRAX). The researchers conducted a meta-analysis of 17,809 people in 14 prospective, population-based cohorts. At mean 6.7-year follow-up, they found that the gradient of risk of TBS for major osteoporotic fracture was 1.44. When additionally adjusted for FRAX 10-year probability of major osteoporotic fracture, they found that TBS remained a significant, independent predictor for fracture. The researchers state that their findings support the use of TBS as a potential adjustment for FRAX probability, although "the impact of the adjustment remains to be determined in the context of clinical assessment guidelines."

Tibial fracture—According to a study published in CORR (online), use of a nonunion prediction model may potentially help determine which patients may be at increased risk of tibial fracture nonunion. The authors retrospectively reviewed data on 382 patients treated with intramedullary nails for tibial shaft fracture. Based on 35 factors theorized to contribute to delayed bone healing, they developed the Nonunion Risk Determination (NURD) score, which assigns 5 points for flaps, 4 points for compartment syndrome, 3 points for chronic condition(s), 2 points for open fractures, 1 point for male gender, and 1 point per grade of American Society of Anesthesiologists Physical Status and percent cortical contact. One point each is subtracted for spiral fractures and for low-energy injuries, which were found to be predictive of union. The authors found that a NURD score of 0 to 5 had a 2 percent chance of nonunion; 6 to 8, 22 percent; 9 to 11, 42 percent; and >12, 61 percent. They state that further work must be done to prospectively validate and enhance the model.

Concussion
TBI in the NFL—A paper to be presented at the annual meeting of the American Academy of Neurology finds that more than 40 percent of retired National Football League (NFL) players involved in the study displayed signs of traumatic brain injury (TBI) based on results of diffusion tensor imaging scans. The scans measure damage to the brain's white matter, based on the movement of water molecules in the brain tissue. Overall, 17 players (43 percent of participants), had levels of movement 2.5 standard deviations below those of healthy people of the same age. The researchers state that study participants played an average of 7 years in the NFL, and reported an average of 8.1 concussions per player.

Pediatric concussion—A study conducted in Canada and presented at the annual meeting of the Pediatric Academic Societies suggests that among children who have sustained a concussion, early resumption of exercise may be associated with faster recovery. The research team tallied survey responses from children regarding their physical activity 7, 14, and 21 days after injury and found that of the children still experiencing concussion symptoms, 58 percent resumed exercising a week after being injured, and more than three-quarters (76 percent) were physically active 2 weeks later—both contrary to recommendations. Exercise within 7 days of injury was associated with nearly half the rate of persistent post-concussive symptoms. The researchers state that the findings do not support fast return to contact drills or games but may point to a benefit from light aerobic activity such as walking, swimming, or stationary cycling, and indicate need for further research.

Basic science
Risks for RA patients—According to a study conducted in Australia and published in Arthritis Research & Therapy (online), compared to the general population, patients with rheumatoid arthritis (RA) who undergo joint surgery may be at increased risk of death at 6 weeks and 12 months. The research team conducted a retrospective cohort study of 240,571 patients (308,589 joint surgeries), 3,654 of whom (1.2 percent) had RA. At 6-week and 12-month follow-up, the investigators found that patients with RA were at increased risk for myocardial infarction (MI), all-cause death, and cardiovascular death. In an analysis of joint surgeries other than hip or knee arthroplasty, the research team noted that patients with RA were at increased risk of MI within 6 weeks and 12 months after surgery compared to those without RA, but found no difference in likelihood of short-term mortality.

Calcium and cardiovascular disease—A study conducted in the United Kingdom and presented at the World Congress on Osteoporosis, Osteoarthritis and Musculoskeletal Diseases finds no link between use of calcium supplements or vitamin D and heart disease or cardiovascular events. The research team drew data from the UK Biobank—a study of 502,663 men and women aged 40 to 69 years. Overall, 34,890 individuals (6.94 percent) reported taking calcium supplements, 20,004 individuals (3.98 percent) reported taking vitamin D supplements, and 10,406 individuals (2.1 percent) reported taking both. The researchers found no associations between the use of calcium supplements or vitamin D and increased hospital admissions related to ischaemic heart disease, any cardiovascular event, or death following admission for either category.

Hand recolonization—Findings from a pilot study published in CORR (online) suggest that it may be beneficial for surgeons to rescrub between the fourth and fifth hours of an operation. The researchers assessed data on 20 spine procedures of 3 hours or more duration, performed by three surgeons using the same scrubbing technique. They found that a longer duration of surgery was associated with more colony-forming units recovered from gloved hands at the end of surgery. The researchers write that the receiver-operating characteristic curve suggested 5 hours as the cutoff point for hand recolonization; at 5 hours, contamination reached or exceeded prescrub levels, whereas before 5 hours, there was no contamination detected at the end of surgery.

Gout and OA—A study published in BMC Musculoskeletal Disorders (online) finds no statistically significant association between gout and hand, knee, and foot osteoarthritis (OA). The study does suggest, however, that people with gout may be more likely to have OA involvement of small joints in the hand and foot, but less likely to have large joint OA at the knee, compared to those without gout. The cross-sectional analysis involved three observational cohorts of patients aged 50 years or younger with hand, knee, and foot pain. Patients were divided into two groups: those with gout (n = 53) and those without gout (n= 211). Each of the gout patients was matched by age and gender to patients without gout. After adjusting for body mass index, diuretic use, and site of joint pain, regression analysis found no statistically significant associations between gout and the presence, frequency, and severity of radiographic hand, knee, or foot OA. However, individuals with gout had increased odds of having nodal hand OA and foot OA, but decreased odds of tibiofemoral or patellofemoral OA in either knee.

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)