Paul J. Girard

A Multicenter, Randomized, Triple-Masked, Placebo-Controlled Trial of The Effect of Ambulatory Continuous Femoral Nerve Blocks on Discharge-Readiness Following Total Knee Arthroplasty In Patients on General Orthopaedic Wards

&NA; A continuous femoral nerve block (cFNB) involves the percutaneous insertion of a catheter adjacent to the femoral nerve, followed by a local anesthetic infusion, improving analgesia following total knee arthroplasty (TKA). Portable infusion pumps allow infusion continuation following hospital discharge, raising the possibility of decreasing hospitalization duration. We therefore used a multicenter, randomized, triple‐masked, placebo‐controlled study design to test the primary hypothesis that a 4‐day ambulatory cFNB decreases the time until each of three predefined readiness‐for‐discharge criteria (adequate analgesia, independence from intravenous opioids, and ambulation ≥30 m) are met following TKA compared with an overnight inpatient‐only cFNB. Preoperatively, all patients received a cFNB with perineural ropivacaine 0.2% from surgery until the following morning, at which time they were randomized to either continue perineural ropivacaine (n = 39) or switch to normal saline (n = 38). Patients were discharged with their cFNB and portable infusion pump as early as postoperative day 3. Patients who were given 4 days of perineural ropivacaine attained all three criteria in a median (25th–75th percentiles) of 47 (29–69) h, compared with 62 (45–79) h for those of the control group (Estimated ratio = 0.80, 95% confidence interval: 0.66–1.00; p = 0.028). Compared with controls, patients randomized to ropivacaine met the discharge criterion for analgesia in 20 (0–38) versus 38 (15–64) h (p = 0.009), and intravenous opioid independence in 21 (0–37) versus 33 (11–50) h (p = 0.061). We conclude that a 4‐day ambulatory cFNB decreases the time to reach three important discharge criteria by an estimated 20% following TKA compared with an overnight cFNB, primarily by improving analgesia.

Continuous peripheral nerve blocks: is local anesthetic dose the only factor, or do concentration and volume influence infusion effects as well?

Background:The main determinant of continuous peripheral nerve block effects—local anesthetic concentration and volume or simply total drug dose—remains unknown. Methods:We compared two different concentrations and basal rates of ropivacaine—but at equivalent total doses—for continuous posterior lumbar plexus blocks after hip arthroplasty. Preoperatively, a psoas compartment perineural catheter was inserted. Postoperatively, patients were randomly assigned to receive perineural ropivacaine of either 0.1% (basal 12 ml/h, bolus 4 ml) or 0.4% (basal 3 ml/h, bolus 1 ml) for at least 48 h. Therefore, both groups received 12 mg of ropivacaine each hour with a possible addition of 4 mg every 30 min via a patient-controlled bolus dose. The primary endpoint was the difference in maximum voluntary isometric contraction (MVIC) of the ipsilateral quadriceps the morning after surgery, compared with the preoperative MVIC, expressed as a percentage of the preoperative MVIC. Secondary endpoints included hip adductor and hip flexor MVIC, sensory levels in the femoral nerve distribution, hip range-of-motion, ambulatory ability, pain scores, and ropivacaine consumption. Results:Quadriceps MVIC for patients receiving 0.1% ropivacaine (n = 26) declined by a mean (SE) of 64.1% (6.4) versus 68.0% (5.4) for patients receiving 0.4% ropivacaine (n = 24) between the preoperative period and the day after surgery (95% CI for group difference: −8.0–14.4%; P = 0.70). Similarly, the groups were found to be equivalent with respect to secondary endpoints. Conclusions:For continuous posterior lumbar plexus blocks, local anesthetic concentration and volume do not influence nerve block characteristics, suggesting that local anesthetic dose (mass) is the primary determinant of perineural infusion effects.

Long-term pain, stiffness, and functional disability after total knee arthroplasty with and without an extended ambulatory continuous femoral nerve block: a prospective, 1-year follow-up of a multicenter, randomized, triple-masked, placebo-controlled trial.

Background: Previously, we have demonstrated that extending a continuous femoral nerve block (cFNB) from overnight to 4 days after total knee arthroplasty (TKA) provides clear benefits during the infusion, but not subsequent to catheter removal. However, there were major limitations in generalizing the results of that investigation, and we subsequently performed a very similar study using a multicenter format, with many health care providers, in patients on general orthopedic wards, thus greatly improving inference of the results to the general population. Not surprisingly, the perioperative/short-term outcomes differed greatly from the first, more limited study. We now present a prospective follow-up study of the previously published, multicenter, randomized controlled clinical trial to investigate the possibility that an extended ambulatory cFNB decreases long-term pain, stiffness, and functional disability after TKA, which greatly improves inference of the results to the general population. Methods: Subjects undergoing TKA received a cFNB with ropivacaine 0.2% from surgery until the following morning, at which time patients were randomized to continue either perineural ropivacaine (n = 28) or normal saline (n = 26). Patients were discharged with their catheter and a portable infusion pump, and catheters were removed on postoperative day 4. Health-related quality of life was measured using the Western Ontario and McMaster Universities Osteoarthritis Index preoperatively and then at 7 days, as well as 1, 2, 3, 6, and 12 months after surgery. This index evaluates pain, stiffness, and physical functional disability. For inclusion in the analysis, we required a minimum of 4 of the 6 time points, including day 7 and at least 2 of months 3, 6, and 12. Results: The 2 treatment groups had similar Western Ontario and McMaster Universities Osteoarthritis scores for the mean area-under-the-curve calculations (point estimate for the difference in mean area under the curve for the 2 groups [overnight infusion group − extended infusion group] = 3.8; 95% confidence interval, −3.8 to +11.3; P = 0.32) and at all individual time points (P > 0.05). Conclusions: This investigation found no evidence that extending an overnight cFNB to 4 days improves (or worsens) subsequent pain, stiffness, or physical function after TKA in patients of multiple centers convalescing on general orthopedic wards.

Stiff muscle fibers in calf muscles of patients with cerebral palsy lead to high passive muscle stiffness

Cerebral palsy (CP), caused by an injury to the developing brain, can lead to alterations in muscle function. Subsequently, increased muscle stiffness and decreased joint range of motion are often seen in patients with CP. We examined mechanical and biochemical properties of the gastrocnemius and soleus muscles, which are involved in equinus muscle contracture. Passive mechanical testing of single muscle fibers from gastrocnemius and soleus muscle of patients with CP undergoing surgery for equinus deformity showed a significant increase in fiber stiffness (p < 0.01). Bundles of fibers that included their surrounding connective tissues showed no stiffness difference (p = 0.28).). When in vivo sarcomere lengths were measured and fiber and bundle stiffness compared at these lengths, both fibers and bundles of patients with CP were predicted to be much stiffer in vivo compared to typically developing (TD) individuals. Interestingly, differences in fiber and bundle stiffness were not explained by typical biochemical measures such as titin molecular weight (a giant protein thought to impact fiber stiffness) or collagen content (a proxy for extracellular matrix amount). We suggest that the passive mechanical properties of fibers and bundles are thus poorly understood.

Effect of Tibial Plateau Fracture on Lubrication Function and Composition of Synovial Fluid

BACKGROUND Intra-articular fractures may hasten posttraumatic arthritis in patients who are typically too active and too young for joint replacement. Current orthopaedic treatment principles, including recreating anatomic alignment and establishing articular congruity, have not eliminated posttraumatic arthritis. Additional biomechanical and biological factors may contribute to the development of arthritis. The objective of the present study was to evaluate human synovial fluid for friction-lowering function and the concentrations of putative lubricant molecules following tibial plateau fractures. METHODS Synovial fluid specimens were obtained from the knees of eight patients (twenty-five to fifty-seven years old) with a tibial plateau fracture, with five specimens from the injured knee as plateau fracture synovial fluid and six specimens from the contralateral knee as control synovial fluid. Each specimen was centrifuged to obtain a fluid sample, separated from a cell pellet, for further analysis. For each fluid sample, the start-up (static) and steady-state (kinetic) friction coefficients in the boundary mode of lubrication were determined from a cartilage-on-cartilage biomechanical test of friction. Also, concentrations of the putative lubricants, hyaluronan and proteoglycan-4, as well as total protein, were determined for fluid samples. RESULTS The group of experimental samples were obtained at a mean (and standard deviation) of 11 ± 9 days after injury from patients with a mean age of 45 ± 13 years. Start-up and kinetic friction coefficients demonstrated similar trends and dependencies. The kinetic friction coefficients for human plateau fracture synovial fluid were approximately 100% higher than those for control human synovial fluid. Hyaluronan concentrations were ninefold lower for plateau fracture synovial fluid compared with the control synovial fluid, whereas proteoglycan-4 concentrations were more than twofold higher in plateau fracture synovial fluid compared with the control synovial fluid. Univariate and multivariate regression analysis indicated that kinetic friction coefficient increased as hyaluronan concentration decreased. CONCLUSIONS Knees afflicted with a tibial plateau fracture have synovial fluid with decreased lubrication properties in association with a decreased concentration of hyaluronan.

Plantar Flexion Influences Radiographic Measurements of the Ankle Mortise

BACKGROUND The treatment of ankle fractures often depends on the integrity of the deltoid ligament. Diagnosis of a deltoid ligament tear depends on the measurement of the medial clear space. We sought to evaluate the impact of ankle plantar flexion on the medial clear space. METHODS Mortise radiographs were made for twenty-five healthy volunteers, with the ankle in four positions of plantar flexion (0 degrees, 15 degrees, 30 degrees, and 45 degrees). Four observers measured the medial clear space and the superior clear space on each radiograph. The mean medial clear space at 0 degrees was defined as the control, and the deviation of the medial clear space from the control value was calculated at 15 degrees, 30 degrees, and 45 degrees of plantar flexion. The ratio of the medial clear space to the superior clear space was determined on all radiographs, and ratios that were false-positive for a deltoid ligament injury were identified. RESULTS Fourteen male and eleven female volunteers were evaluated. The average increase in the medial clear space when ankle plantar flexion was increased from 0 degrees to 45 degrees was 0.38 mm (95% confidence interval, 0.18 to 0.58 mm). This increase was significant (p = 0.005). The average increase in the medial clear space was 0.04 mm when ankle plantar flexion was increased from 0 degrees to 15 degrees and 0.22 mm when it was increased from 0 degrees to 30 degrees. Neither of these changes was significant (p = 0.99 and 0.20). The prevalence of false-positive findings of deltoid injury based on the ratio of the medial clear space to the superior clear space increased as ankle plantar flexion increased, but this increase did not reach significance in our study group (p = 0.18). CONCLUSIONS Plantar flexion of the ankle produces changes in radiographic measurements of the medial clear space. The potential for false-positive findings of deltoid disruption increases with increasing ankle plantar flexion.

Injuries sustained in noncombat motor vehicle accidents during Operation Iraqi Freedom

OBJECTIVE To examine injuries sustained in noncombat motor vehicle accidents (MVAs) during Operation Iraqi Freedom by injury type, site, and severity. METHODS Three hundred and forty-eight military personnel injured in noncombat MVAs from March 2004-June 2007 were identified from clinical records completed near the point of injury. RESULTS On average, personnel suffered two injuries per accident. The most frequent MVA mechanism was non-collision due to loss of control (30%). Overall, 16% were injured in a collision accident and 19% in a rollover accident. Rollovers were associated with more severe injuries. A greater proportion of drivers sustained head/neck/face injuries, whereas gunners and pedestrians had higher percents of extremity injuries. CONCLUSIONS This analysis provides a thorough overview of injuries incurred in nonbattle MVAs in the combat environment. Future research should combine injury data with accident reports to elucidate areas for improvements in vehicle safety.

Anterior Sacroiliac Dislocation

Injuries to the sacroiliac joints are most commonly caused by high-energy trauma. Orthopaedic traumatologists frequently treat sacroiliac dislocations and fracture-dislocations as part of the spectrum of pelvic ring injuries. Typical sacroiliac joint dislocations are posterior; anterior dislocations are extremely rare. As with posterior dislocations, these are high-energy injuries with concomitant visceral, neurologic, and other osseous injuries. We describe a case of anterior sacroiliac dislocation that was treated with a closed reduction and percutaneous fixation in a trauma patient with multiple injuries. The patient was informed that data concerning the case would be submitted for publication, and she provided consent. A twenty-one-year-old unrestrained driver was involved in a head-on collision with a tree at an unknown speed after reportedly attempting to avoid pedestrians in the road. She was initially evaluated in Mexico and was transferred to our level-I trauma center twelve hours after the accident. On admission to the trauma bay, the initial vital signs were blood pressure of 122/70 mm Hg, heart rate of 94 bpm, respiration of 24 bpm, and oxygen saturation of 100% on 2 L per nasal cannula. The initial hemoglobin and hematocrit levels were 10.9 g/dL and 31.6%, respectively. On examination, the patient was alert and oriented with a Glasgow Coma Scale score of 15. The spine was nontender, but she did have tenderness to palpation in the left sacroiliac region with accompanying ecchymosis posteriorly. The pelvis was unstable with lateral and anteroposterior compression. The patient had complete loss of sensation and motor function of the left lower extremity, although she had normal peripheral pulses in all four extremities. Perineal examination revealed no open wounds; however, there was left labial swelling and ecchymosis. A Foley catheter had been placed prior to arrival, and gross blood was identified in the urine. The stool guaiac test was negative, …