Ultrasound-Guided Percutaneous Cryoneurolysis for Perioperative Analgesia Following Major Lower Extremity Amputation: A Randomized, Participant- and Observer-Masked, Sham-Controlled Pilot Study

BACKGROUND

Extremity amputations are associated with pain in both the residual limb and the phantom limb. This pain, which is often debilitating, may be prevented by excellent perioperative pain control. Ultrasound-guided percutaneous cryoneurolysis is an analgesic modality offering pain control for weeks or months following surgery. This treatment has not been compared to the sham procedure for large nerves (e.g., femoral and sciatic) to provide preoperative analgesia. We therefore conducted a randomized, controlled pilot study to evaluate the use of this modality for the treatment of pain following amputation to (1) determine the feasibility of and optimize the study protocol for a subsequent definitive clinical trial; and (2) estimate analgesia and opioid reduction within the first postoperative weeks.

METHODS

A convenience sample of seven patients undergoing lower extremity amputation were randomized to receive either active cryoneurolysis or a sham procedure targeting the sciatic and femoral nerves in a participant-masked fashion. This was a pilot study with a relatively small number of participants, and therefore the resulting data were not analyzed statistically.

RESULTS

Compared to the participants who received sham treatment (n=3), those who underwent active cryoneurolysis (n=4) reported lower pain scores and decreased opioid consumption at nearly all time points between days one and 21 following amputation.

CONCLUSIONS

Ultrasound-guided percutaneous cryoneurolysis of the femoral and sciatic nerves prior to lower extremity amputation appears feasible and potentially effective. The data from this pilot study may be used to power a definitive randomized clinical trial.

Fracture blisters: predictors for time to definitive fixation in pilon fractures

PURPOSE

Fracture blisters, a common soft-tissue complication of pilon fractures, are associated with post-operative wound infections, delays in definitive fixation, and alterations in surgical plan. The purpose of this study was to (1) identify the delay in surgery attributable to the presence fracture blisters and (2) investigate the relationship of fracture blisters to comorbidities and fracture severity.

METHODS

Patients with pilon fractures at an urban level 1 Trauma center from 2010 to 2021 were identified. The presence or absence of fracture blisters was noted, along with location. Demographic information, time from injury to external fixator placement, and time to definitive open reduction internal fixation (ORIF) were collected. Pilon fractures were classified according to AO/OTA guidelines using CT imaging and plain radiographs.

RESULTS

314 patients with pilon fractures were available for analysis, eighty (25%) of whom were found to have fracture blisters. Patients with fracture blisters had longer time to surgery compared to those without fracture blisters (14.2 days vs 7.9 days, p < 0.001). A greater proportion of patients with fracture blisters had AO/OTA 43C fracture patterns, compared with those without fracture blisters (71.3% vs 53.8%, p = 0.03). Fractures blisters were less likely to be localized over the posterior ankle (12%, p = 0.007).

CONCLUSION

The presence of fracture blisters in pilon fractures are associated with significant delays in time to definitive fixation and higher energy fracture patterns. Fracture blisters are less commonly located over the posterior ankle which may support the implementation of a staged posterolateral approach when managing these injures.

Characterization of electric scooter injuries over 27 months at an urban level 1 trauma center

BACKGROUND

Electric scooters (e-scooters) have become a widespread method of transportation. The purpose of this study is to provide risk stratification tools for modifiable risk factors associated with e-scooter injury morbidity.

METHODS

Patients at an urban Level 1 Trauma center sustaining e-scooter injuries between November 2017 through March 2020 were identified. Primary outcomes of interest were major trauma, as defined by an Injury Severity Score (ISS) >15, or hospital admission.

RESULTS

A total of 442 patients sustained orthopaedic (51%), facial (31%), cranial (13%), and chest/abdominal injuries (4.5%). Rate of helmet use was 2.5%, hospital admission was 40.7%, and intensive care was 3%. Patients with facial injuries were half as likely to sustain major trauma as compared to orthopaedic injuries (p < 0.05). Factors with higher likelihood of hospital admission included age > 40 years (OR 4.20, p < 0.01), alcohol or other substance intoxication (OR 4.14 and 9.87, p < 0.001), loss of consciousness (OR 2.72, p < 0.003), or transport to the hospital by ambulance (OR 4.47, p < 0.001).

CONCLUSIONS

There is a substantial proportion of major trauma within e-scooter injuries. Modifiable risk factors for hospital admission include use of head protection and substance use while riding e-scooters.

Financial impact of electric scooters: a review of injuries over 27 months at an urban level 1 trauma center (cost of e-scooter injuries at an urban level 1 trauma center)

BACKGROUND

Electric scooters (e-scooters) have become a widespread method of transportation due to convenience and affordability. However, the financial impact of medical care for sustained injuries is currently unknown. The purpose of this study is to characterize total billing charges associated with medical care of e-scooter injuries.

METHODS

A retrospective review of patients with e-scooter injuries presenting to the trauma bay, emergency department or outpatient clinics at an urban level 1 trauma center was conducted from November 2017 to March 2020. Demographic and clinical data were collected. Primary outcomes of interest were total billing charges and billing to insurance (hospital and professional). Multivariable models were used to identify preventable risk factors associated with higher total billing charges.

RESULTS

A total of 63 patients were identified consisting of 42 (66.7%) males, average age 40.19 (SD 13.29) years and 3.2% rate of helmet use. Patients sustained orthopedic (29%, n=18), facial (48%, n=30) and cranial (23%, n=15) injuries. The average total billing charges for e-scooter clinical encounters was $95 710 (SD $138 215). Average billing to insurance was $86 376 (SD $125 438) for hospital charges and $9 334 (SD $14 711) for professional charges. There were no significant differences in charges between injury categories. On multivariable regression, modifiable risk factors independently associated with higher total billing charges included any intoxication prior to injury ($231 377 increase, p=0.02), intracranial bleeds ($75 528, p=0.04) and TBI ($360 898, p=0.006).

DISCUSSION

Many patients sustain high-energy injuries during e-scooter accidents with significant medical and financial consequences. Further studies may continue expanding the financial impact of e-scooter injuries on both patients and the healthcare system.

LEVEL OF EVIDENCE

III.

Antibiotic-Impregnated Intramedullary Cement Nail-Induced Acute Generalized Exanthematous Pustulosis and Septic Shock: A Case Report

CASE

A 28-year-old woman with an infected proximal femur nonunion was treated with an antibiotic-coated intramedullary nail. Shortly after discharge, the patient presented to the emergency department and was readmitted with a morbilliform rash sparing the left lower extremity. She became hemodynamically unstable, despite cessation of intravenous antibiotics, requiring transfer to the intensive care unit and urgent removal of her antibiotic nail. She improved after surgery, and biopsy results from the rash confirmed acute generalized examthematous pustulosis.

CONCLUSION

Acute generalized exanthematous pustulosis is a rare, dermatologic crisis that can be precipitated by antibiotics, even in the form of antibiotic cement.

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.

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

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 30m) 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.

Comparative efficacy of ultrasound-guided and stimulating popliteal-sciatic perineural catheters for postoperative analgesia

PURPOSE

Perineural catheter insertion using ultrasound guidance alone is a relatively new approach. Previous studies have shown that ultrasound-guided catheters take less time to place with high placement success rates, but the analgesic efficacy compared with the established stimulating catheter technique remains unknown. We tested the hypothesis that popliteal-sciatic perineural catheter insertion relying exclusively on ultrasound guidance results in superior postoperative analgesia compared with stimulating catheters.

METHODS

Preoperatively, subjects receiving a popliteal-sciatic perineural catheter for foot or ankle surgery were assigned randomly to either ultrasound guidance (bolus via needle with non-stimulating catheter insertion) or electrical stimulation (bolus via catheter). We used 1.5% mepivacaine 40 mL for the primary surgical nerve block and 0.2% ropivacaine (basal 8 mL·hr(-1); bolus 4 mL; 30 min lockout) was infused postoperatively. The primary outcome was average surgical pain on postoperative day one.

RESULTS

Forty of the 80 subjects enrolled were randomized to each treatment group. One of 40 subjects (2.5%) in the ultrasound group failed catheter placement per protocol vs nine of 40 (22.5%) in the stimulating catheter group (P = 0.014). The difference in procedural duration (mean [95% confidence interval (CI)]) was -6.48 (-9.90 - -3.05) min, with ultrasound requiring 7.0 (4.0-14.1) min vs stimulation requiring 11.0 (5.0-30.0) min (P < 0.001). The average pain scores of subjects who provided data on postoperative day one were somewhat higher for the 33 ultrasound subjects than for the 26 stimulation subjects (5.0 [1.0-7.8] vs 3.0 [0.0-6.5], respectively; P = 0.032), a difference (mean [95%CI]) of 1.37 (0.03-2.71).

CONCLUSION

For popliteal-sciatic perineural catheters, ultrasound guidance takes less time and results in fewer placement failures compared with stimulating catheters. However, analgesia may be mildly improved with successfully placed stimulating catheters. Clinical trial registration number NCT00876681.

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.

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.

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.