Study IDs risk factors for THA revision after infection
Danish researchers have identified several categories of patients at higher risk of revision surgery because of infection after total hip arthroplasty (THA). To determine the rates of revision (defined as extraction or exchange of any component) and the relative risk of revision done because of infection, investigators analyzed the records of more than 80,000 patients who had primary THA during a 14-year period. The median follow-up time was 5 years.
During the study period, 597 primary THAs (0.7%) were revised because of infection. The following groups had the greatest relative risk of revision surgery because of infection:
- patients with any comorbidity;
- patients operated on for nontraumatic femoral head osteonecrosis; and
- patients with long duration of initial THA surgery.
Patients who had either cemented THA without antibiotics or hybrid THA tended to have an increased risk of revision compared with patients with cementless implants. Hip diagnosis and fixation technique were not associated with risk of revision after infection within 1 year of surgery.
The investigators called for further research to explain the mechanism underlying the increased risk. They also asked that clinicians devote more attention to infection prevention strategies in patients who undergo THA, particularly those at increased risk for infection.
Source: Pedersen AB, Svendsson JE, Johnsen SP, Riis A, Overgaard S. Risk factors for revision due to infection after primary total hip arthroplasty. Acta Orthop. 2010 Sep 22. [Epub ahead of print]
Hip surgery soon after fracture reduces mortality
Geriatric patients who have surgery soon after fracturing a hip have a 19% lower mortality risk compared with patients whose surgery is delayed, new research shows. Current guidelines recommend surgery within 24 hours after a hip fracture; however, some doctors delay surgery to decrease the risk of perioperative complications.
In the study, Canadian researchers conducted a systematic review and meta-analysis to determine the effect of early surgery on the risk of death and common postoperative complications among elderly patients with hip fractures. The review involved 16 studies that included a total of 13,478 patients age 60 years and older.
They found that surgery performed within 72 hours after hip fracture greatly reduces mortality risk and may lower the risk of postoperative pneumonia and pressure sores. Hip fractures are associated with a 14 to 36% mortality rate in the year after fracture.
Source: Simunovic N, Devereaux PJ, Sprague S, Guyatt GH, Schemitsch E,et al. Effect of early surgery after hip fracture on mortality and complications: systematic review and meta-analysis. CMAJ. 2010 Sep 13. [Epub ahead of print]
Short or extended thromboprophylaxis after TKA?
In a randomized, open trial, French researchers compared outcomes in 842 patients who underwent total knee arthroplasty (TKA) and were treated with either "short" (10-day) or "extended"(35-day) thromboprophylaxis. Because the investigators documented that the risk of clinically significant venous thromboembolic events persists longer than 7 days after TKA, they concluded that extending prophylaxis with anticoagulant drugs for a further 3 to 4 weeks after TKA reduces the risk of delayed venous thromboembolism without compromising safety.
Extended prophylaxis was not associated with an increased risk of bleeding; regardless of prophylaxis duration, bleeding risk was low (0.7%). Asymptomatic distal deep vein thrombosis (DVT) detected 7 days after surgery seemed to predict more severe subsequent thromboembolic events.
Investigators suggest screening for asymptomatic distal DVT to identify patients whose level of risk justifies a longer duration of prophylaxis. In patients who have a lower risk of DVT, short-term prophylaxis may be sufficient. Until further proof of this recommendation is obtained, however, the authors conclude that the most appropriate strategy for most patients with TKA is systematic extended prophylaxis.
Source: Barrellier MT, Lebel B, Parienti JJ, Mismetti P, Dutheil JJ, et al. Short versus extended thromboprophylaxis after total knee arthroplasty: a randomized comparison. Thromb Res. 2010;126(4):e298-304.
Tallying complications after RTSA
Earlier research indicates that reverse total shoulder arthroplasty (RTSA) has a complication rate 4 times that of conventional total shoulder arthroplasty. In a new study, investigators performed a systematic review and meta-analysis to identify the most common and serious complications of RTSA and to review current methods of prevention and treatment.
Although the methodology of collecting and reporting data from previous research limited the study, a definitive ranking of most common to least common complications after RTSA emerged.
The most common complication is scapular notching. The most clinically relevant complications are infection, instability, and acromial fractures. Hematoma was common in the past but can now be prevented. Glenoid component loosening, however, is rare when compared with conventional total shoulder replacement.
Investigators concluded that RTSA is associated with a high rate of complications, but their incidence and the results of treatment for complications are inconsistently reported. Documentation and prevention of complications would require a standardized monitoring tool with clear definitions and assessment instructions.
Source: Farshad M, Gerber C. Reverse total shoulder arthroplasty--from the most to the least common complication. Int Orthop. 2010 Sep 25. [Epub ahead of print]
How common is failure with Birmingham hip resurfacing?
Despite increasing interest in and published reports of hip resurfacing arthroplasty, little is known regarding the prevalence of complications or the less common modes of failure. From a multi-surgeon series (141 surgeons) of 5000 Birmingham hip resurfacings, investigators analyzed the mode, prevalence, gender difference, and time to failure of hips requiring revision.
During the study, 182 hips were revised (3.6%). The most common cause for revision was a fracture of the neck of the femur (54 hips, prevalence 1.1%); followed by loosening of the acetabular component (32 hips, 0.6%); collapse of the femoral head/avascular necrosis (30 hips, 0.6%); loosening of the femoral component (19 hips, 0.4%); infection (17 hips, 0.3%); pain with aseptic lymphocytic vascular and associated lesions (ALVAL)/metallosis (15 hips, 0.3%); loosening of both components (5 hips, 0.1%); dislocation (5 hips, 0.1%); and malposition of the acetabular component (3 hips, 0.1%). The cause of failure was unknown in 2 cases.
The prevalence of revision is significantly higher in women than in men (women, 5.7%; men, 2.6%). Compared with men, women had significantly more revisions for loosening of the acetabular component, dislocation, infection and pain/ALVAL/metallosis.
The average time to failure was 2.9 years for all causes, with revision for fracture of the neck of the femur occurring earlier than revision for other causes (average, 1.5 years). There was a significantly shorter time to failure in men (average, 2.1 years) compared with women (average, 3.6 years).
Source: Carrothers AD, Gilbert RE, Jaiswal A, MBBS, Richardson JB. Birmingham hip resurfacing: the prevalence of failure. J Bone Joint Surg Br. 2010; 92-B(10):1344-1350.
How common are fractures after lumbar spinal fusion?
Postmenopausal women who have lumbar spinal instrumentation surgery are at risk for subsequent vertebral fractures within 2 years after surgery, new research suggests. Also, the greater the number of spinal segments between the fracture and the instrumentation, the longer the period between surgery and subsequent fracture.
Investigators performed a retrospective analysis of 100 consecutive patients, 55 years of age or older, who had spinal fusion for degenerative diseases between L1 and S1 and instrumentation of fewer than 4 segments. Patients were excluded if they had prevalent vertebral fractures at the time of surgery; secondary causes of osteoporosis (e.g., corticosteroids, endocrine disorders, neoplastic disease, GI disorder); bone mineral density of less than 80% of normal; or were taking medication for osteoporosis. The average follow-up period was 10.2 years (range, 7-14 years).
Using MRI and lateral spine radiographs, the authors identified acute vertebral fractures in 20 vertebrae among 14 (24%) of the 59 women in the study, compared with a vertebral fracture in 1 (2%) of the 41 men. Eighteen of the 21 fractures occurred within 2 years of the spinal instrumentation operation. Adjacent-level fractures occurred within 8 months of surgery, and remote level fractures occurred between 8 and 22 months after surgery.
Source: Toyone T, Ozawa T, Kamikawa K, Watanabe A, Matsuki K, et al. Subsequent vertebral fractures following spinal fusion surgery for degenerative lumbar disease: a mean ten-year follow-up. Spine. 2010;35(21):1915-1918.
Comparing treatments for adolescent idiopathic thoracic scoliosis
Bracing is effective for preventing curve progression in the coronal plane in patients with mild or moderate adolescent idiopathic scoliosis (AIS), but a few studies have found a hypokyphotic effect on the sagittal plane. An increasing number of patients with AIS wear a new kind of elastic orthotic belt to treat scoliosis without doctors' instructions. Researchers compared the effects of the elastic orthotic belt and the Milwaukee brace on sagittal alignment in patients with AIS.
Twenty-eight female patients with mild or moderate thoracic curves were included in this study. Standing, full-length, lateral radiographs were obtained with the patients in natural standing posture without any treatment; with the elastic orthotic belt; and with the Milwaukee brace. Investigators compared patients' thoracic kyphosis, lumber lordosis, and pelvic incidence among these 3 conditions.
Both the elastic orthotic belt and the Milwaukee brace produced a significant decrease in thoracic kyphosis. The decrease in kyphosis observed after patients wore the elastic orthotic belt was significantly greater than that achieved after they wore the Milwaukee brace. Compared with no treatment, lumbar lordosis was significantly decreased after use of the Milwaukee brace, but not after use of the elastic orthotic belt. No significant changes were observed in pelvic incidence among the 3 conditions.
The authors concluded that the elastic orthotic belt could lead to more severe thoracic hypokyphosis than the Milwaukee brace, and that the elastic orthotic belt may not be a suitable conservative method for treating mild and moderate AIS.
Source: Jiang J, Qiu Y, Mao S, Zhao Q, Qian B, et al. The influence of elastic orthotic belt on sagittal profile in adolescent idiopathic thoracic scoliosis: a comparative radiographic study with Milwaukee brace. BMC Musculoskelet Disord. 2010 Sep 23;11(1):219. [Epub ahead of print]
Pedicle screw insertion accuracy with various assisted methods
Navigation systems that provide intraoperative assistance might improve the accuracy of pedicle screw insertion, according to previous research. And, different systems may offer varying degrees of pedicle screw insertion accuracy.
Investigators conducted a systematic review and meta-analysis to determine pedicle screw insertion accuracy with or without the use of an image-guided system as well as the variance among the different systems. In all, 43 papers were included in the study.
The incidence of pedicle violation among computed tomography-based navigation methods was significantly less than that observed with the conventional methods. A 2-dimensional fluoroscopy-based navigation system and a 3-dimensional fluoroscopy-based navigation system also were associated with significantly reduced screw deviation rates compared with traditional methods.
A pooled estimate of in vitro studies showed that computed tomography-based and 3-dimensional fluoroscopy-based navigation systems provide more accurate pedicle screw insertion than a 2-dimensional fluoroscopy-based navigation system.
Researchers concluded that navigation provides higher accuracy in the placement of pedicle screws than conventional methods. The superiority of navigation systems was obvious when they were applied to abnormal spinal structures. Although no strong in vivo evidence has detected significantly different pedicle screw placement accuracy, meta-analysis revealed variance in pedicle screw insertion accuracy among the 3 major navigation systems.
Source: Tian NF, Huang QS, Zhou P, Zhou Y, Wu RK, et al. Pedicle screw insertion accuracy with different assisted methods: a systematic review and meta-analysis of comparative studies. Eur Spine J. 2010 Sep 23. [Epub ahead of print]
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