Surgical infection rates differ with anesthesia type
Rates of surgical site infection (SSI) after total hip or knee replacement surgery are lower when epidural or spinal anesthesia is used instead of general anesthesia, according to new study results. Researchers write that their results support the developing concept that general anesthesia has long-term consequences.
In a retrospective analysis, researchers evaluated the relationship between the method of anesthesia and SSI within 30 days postoperatively. The study group comprised 3081 patients who underwent primary total hip or knee replacement surgery. In all, 56 patients had an SSI in the 30 days after surgery. Of those, 33 had received general anesthesia, and 23 had received spinal or epidural anesthesia. Of patients who received general anesthesia, 2.8% developed an SSI. In comparison, 1.2% of patients who received spinal or epidural anesthesia developed an SSI.
After adjusting for confounding variables, investigators found that patients who had general anesthesia were 2.2 times more likely to develop an SSI than were those who had spinal or epidural anesthesia.
An accompanying editorial offers three possible explanations for the lower incidence of SSI with spinal or epidural anesthesia. First, spinal/epidural anesthesia modulates the inflammatory response to surgery and may allow the immune system to fight bacteria more effectively. Second, this method of anesthesia may improve the blood's ability to carry oxygen to tissue. Third, it may also provide excellent analgesia even after surgery.
Sources: Chang CC, Lin HC, Lin HW, Lin HC. Anesthetic management and surgical site infections in total hip or knee replacement: a population-based study. Anesthesiology. 2010 Aug;113(2):279-284. Sessler DI. Neuraxial anesthesia and surgical site infection. Anesthesiology. 2010 Aug;113(2):265-267.
ACL tears: OK not to rush to surgery?
Some patients with a torn anterior cruciate ligament (ACL) can delay or forgo surgical repair and suffer no adverse effects, new study results suggest. In the study, a Danish team of investigators randomly assigned 121 active, young adults with ACL injuries to early ACL reconstructive surgery plus rehabilitation or rehabilitation with surgery conducted later on, if necessary.
Among the 59 patients randomized to rehabilitation, 23 underwent reconstruction surgery later. The other 36 patients did not. In pain, function, and "knee-related quality of life," the investigators found no differences 2 years after injury among patients who underwent early knee reconstruction, those who had rehabilitation plus delayed reconstruction, and those who only underwent rehabilitation.
"A strategy of initial supervised rehabilitation-only was associated with a reduction of the surgery rate by 60%," reported study co-author Ewa Roos, PhD, professor and head of the Research Unit for Musculoskeletal Function and Physiotherapy at the University of Southern Denmark, Odense.
The results suggest that treatment for active young adults with acute ACL injury should begin with structured rehabilitation rather than early ACL reconstruction, said coauthor Richard B. Frobell, PhD, of the department of orthopedics at Lund University in Sweden. "By doing so, the number of patients in need of reconstructive surgery could be reduced to less than 50% without compromising the results," he said.
In an editorial that accompanied the study, Bruce A. Levy, MD, of the department of orthopedic surgery at the Mayo Clinic in Rochester, MN, recommends evaluating patients on a case-by-case basis because waiting to reconstruct an ACL injury isn't always a clinically sound choice. For instance, if an ACL injury is combined with another knee injury, such as a repairable rip in the meniscus, surgery to repair both is needed or the meniscus repair will fail.
Sources: Frobell RB, Roos EM, Roos HP, Ranstam J, Lohmander LS. A randomized trial of treatment for acute anterior cruciate ligament tears. N Engl J Med. 2010;363(4):331-342. Levy BA. Is early reconstruction necessary for all anterior cruciate ligament tears? N Engl J Med. 2010;363(4):386-388.
Plates vs. nails for midshaft clavicular fractures
Is it better to use plates and screws or intramedullary nails to stabilize displaced midclavicular fractures? Turns out both methods work equally well, according to new research.
Investigators performed a retrospective comparison of a sample of 110 patients (ages 16 to 65 years) who had received either plates or nails for completely displaced midshaft clavicular fractures. There were 59 plate-fixed and 51 nail-fixed patients. The two groups were not significantly different in age, sex, height, dominant arm, fracture angulation, fracture shortening, total fracture displacement, or mechanism of injury.
Outcomes were significantly better in the plate group compared with the nail group for length of hospital stay (4.6 days +/- 2.1 days vs. 5.9 days +/- 2.6 days), operative blood loss (67.5 mL +/- 36.2 mL vs. 127.9 mL +/- 48.8 mL), and size of surgical wound (11.9 cm +/- 4.4 cm vs. 22.3 cm +/- 4.5 cm).
There were no significant differences between the two groups in various other factors: operative time; time to union; restoration of mobility (forward flexion, abduction, external rotation, and internal rotation); number of nonunions; number of malunions; infection rate; need for hardware removal; early mechanical failure; time to return to work; Constant Shoulder scores; and Disabilities of the Arm, Shoulder, and Hand functional scores.
Source: Liu HH, Chang CH, Chia WT, Chen CH, Tarng YW, Wong CY. Comparison of plates versus intramedullary nails for fixation of displaced midshaft clavicular fractures. J Trauma. 2010 Jul 20. [Epub ahead of print]
Articulating spacers abrade with time
Articulating spacers used in two-stage revision surgery of infected hip and knee prostheses can abrade and cause third-body wear of the new prosthesis. Can the particulate material abraded from spacers be detected in the synovial membrane? Researchers tested for its presence by removing patients' synovial membranes 6 weeks after implantation, when the spacers were removed for the second stage of the revision.
The study involved 16 hip spacers (cemented prosthesis stem articulating with a cement cup) and four knee spacers (customized mobile cement spacers). The removed membranes were analyzed for the presence of abraded particles originating from the spacer material.
In all membranes, researchers found zirconium dioxide in substantial amounts. In the specimens of hip synovial lining, they documented particles that originated from the metal heads of the spacers. On histologic analysis, zirconium oxide particles were in the synovial membrane of every spacer, and bone cement particles were present in one knee and two hip spacers.
Because cement spacers seem to abrade within 6 weeks of placement, and they leave debris in the synovial membrane, researchers recommend total synovectomy and extensive lavage during second-stage reimplantation surgery. These steps should reduce the number of abraded particles and the amount of bacteria.
Source: Fink B, Rechtenbach A, Büchner H, Vogt S, Hahn M. Articulating spacers used in two-stage revision of infected hip and knee prostheses abrade with time. Clin Orthop Relat Res. 2010 Jul 28. [Epub ahead of print]
Correcting claw toe deformity with a modified technique
Is modified plantar plate tenodesis safe and effective for correction of claw toe deformity? In a recent study, researchers performed modified plantar plate tenodesis in 10 fresh-frozen cadaver feet with claw toe deformity of the second toe. A figure-eight suture anchored the plantar plate of the second metatarsophalangeal joint to the extensor digitorum longus tendon. The investigators evaluated the figure-eight construct and the relationship of the digital nerve and the suture.
In a separate clinical study, researchers also analyzed the operative time, degree of correction, and improvement in the American Orthopaedic Foot and Ankle Society (AOFAS) score between two groups. Group 1 had the original plantar plate tenodesis, and Group 2 underwent the modified technique. The authors noted any neural injury.
In the cadaveric study, the claw toe deformity was corrected, and no nerve injury occurred in any specimen. Flexor tendon tethering by the suture occurred in two specimens. In the clinical study, the average operative time was 51 minutes for Group 1 and 31 minutes for Group 2. AOFAS score improved an average of 44 in Group 1 and 43 in Group 2. The corrective power of the sagittal plane deformity at the metatarsophalangeal joint averaged 25 degrees in Group 1 and 23 degrees in Group 2.
Plantar plate tenodesis was effective in correcting flexible claw second-toe deformity by stabilization of the attenuated plantar plate. The modified technique offered easier suture retrieval and shorter operative time, but it may tether the flexor tendon.
Source: Lui TH, Chan LK, Chan KB. Modified plantar plate tenodesis for correction of claw toe deformity. Foot Ankle Int. 2010;31(7):584-591.
Does surgical technique during TKA affect gait?
Researchers compared gait in patients who had total knee arthroplasty (TKA) performed in one of three ways: conventional technique, computer-assisted navigation, or minimally invasive technique combined with computer-assisted navigation.
Each surgical technique was performed in a group of 15 patients: group 1 had the conventional technique, group 2 had computer-assisted surgery, and group 3 underwent the minimally invasive technique and computer-assisted surgery. The Zebris gait analysis system was used to obtain numeric data for kinetic and kinematic gait parameters.
Researchers analyzed gait preoperatively and 3, 6, 9, and 12 months after surgery. They measured range of motion of the pelvis, hip, and knee during walking and the step width and stride length.
Investigators compared results with parameters measured in a group of healthy people of the same age. Parameter values in groups 1 and 2 reached the value of the control group 6 months after surgery. Group 3 reached the control group value 3 months after surgery. The researchers concluded that navigation does not greatly influence the length of rehabilitation, but rehabilitation may be faster with minimally invasive surgery.
Source: Bejek Z, Paróczai R, Szendrői M, Kiss RM. Gait analysis following TKA: comparison of conventional technique, computer-assisted navigation and minimally invasive technique combined with computer-assisted navigation. Knee Surg Sports Traumatol Arthrosc. 2010 Jul 22. [Epub ahead of print]
Link between fast-track TKA and THA and readmission rates?
With fast-track surgery, the postoperative convalescent period is shorter; patients reach functional milestones earlier; and their length of stay (LOS) decreases. But, is decreased LOS triggering increased rates of readmission, risk of dislocation after total hip arthroplasty (THA), or risk of manipulation after total knee arthroplasty (TKA)?
To find out, researchers conducted a study involving 1731 patients who underwent primary THA or TKA from 2004 to 2008 in a well-designed fast-track setup. All readmissions and deaths within 90 days were analyzed using the Danish national health register.
During the study period, average LOS decreased from 6.3 to 3.1 days. Within 90 days, 15.6% of patients who underwent TKA were readmitted compared with 10.9% who had THA. Three deaths (0.17%) were associated with clotting episodes.
Half of the readmissions were attributable to suspected deep venous thrombosis (not found) or infection. Readmissions in general and for thromboembolic events, dislocations, and manipulations did not increase with decreasing LOS. LOS had no effect on annual readmission rates among patients who underwent TKA or THA; however, the risk of dislocation decreased significantly along with decreased LOS.
Researchers conclude that fast-track TKA and THA do not increase readmission rates. Readmissions, in general, are more frequent after TKA than THA. Rates of dislocation after THA and manipulation after TKA do not increase as LOS decreases.
Source: Husted H, Otte KS, Kristensen BB, Orsnes T, Kehlet H. Readmissions after fast-track hip and knee arthroplasty. Arch Orthop Trauma Surg. 2010 Jun 10. [Epub ahead of print]
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