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Biomedical subjects

Thomas W Wright

Publications and source records attributed to Thomas W Wright.

At least 19 recordsLinked to original sources
PubMed2006

Loading of the index metacarpal after trapezial and partial versus complete trapezoid resection.

PURPOSE: To examine the effects of partial or complete trapezoidectomy in conjunction with trapezium resection on proximal migration of the index metacarpal during axial loading. METHODS: Five specimens from below the elbow were obtained from fresh-frozen cadavers. A customized vise was used to position the wrist in 20 degrees extension and 5 degrees ulnar deviation, simulating a power grip. The index metacarpal was instrumented to allow axial loading at 125 N and 250 N. Specimens were tested under 4 experimental conditions: (1) in the intact state, (2) after trapezial resection, (3) after partial trapezoid resection, and (4) after complete trapezoid resection. Specimens were tested 5 times under each experimental condition, displacement was measured with a linear variable differential transformer, and stiffness was calculated. RESULTS: There was no difference in stiffness between the different treatments at either 125 N or 250 N. Displacement was not significantly different between treatments for loads of 125 N. For loads of 250 N the displacement was approximately 1 mm greater with complete trapezoid resection than with any of the other treatment conditions. Displacement did not differ significantly between the other 3 treatments. CONCLUSIONS: The addition of a partial trapezoid resection performed at the time of trapezial resection does not affect proximal migration of the second metacarpal. When a complete trapezoidectomy is performed at the time of trapezial excision, however, the loading characteristics of the index metacarpal do change statistically significantly, although the magnitude of that change is only approximately 1 mm. Further testing will be necessary to elucidate the biomechanical effects of a partial trapezoid resection in conjunction with a trapezial resection on the second metacarpal in other planes.

Cadaver↗
PubMed2006

Ambulatory continuous interscalene nerve blocks decrease the time to discharge readiness after total shoulder arthroplasty: a randomized, triple-masked, placebo-controlled study.

BACKGROUND: A continuous interscalene nerve block (CISB) may be used to provide analgesia after shoulder arthroplasty. Therefore, inpatient stays may be shortened if CISB (1) provides adequate analgesia without intravenous opioids and (2) improves shoulder mobilization. This study investigated the relationship between ambulatory CISB and the time to reach three discharge criteria after shoulder arthroplasty. METHODS: Preoperatively, patients received a CISB. All patients received a perineural 0.2% ropivacaine infusion from surgery until 06:00 the following morning, at which time they were randomly assigned either to continue perineural ropivacaine or to switch to normal saline. The primary endpoint was the time from the end of surgery until three discharge criteria were attained (adequate analgesia, independence from intravenous analgesics, and tolerance to 50% of shoulder motion targets). Patients were discharged home as early as the afternoon after surgery with their CISB using a portable infusion pump. RESULTS: Patients receiving perineural ropivacaine (n = 16) attained all three discharge criteria in a median (10th-90th percentiles) of 21 (16-41) h, compared with 51 (37-90) h for those receiving perineural normal saline (n = 13, P < 0.001). Unlike patients receiving perineural ropivacaine, patients receiving perineural normal saline often required intravenous morphine, but still experienced a higher degree of pain and tolerated less external rotation. CONCLUSIONS: An ambulatory CISB considerably decreases the time until readiness for discharge after shoulder arthroplasty, primarily by providing potent analgesia that permits greater passive shoulder movement and the avoidance of intravenous opioids. Additional research is required to define the appropriate subset of patients and assess the incidence of complications associated with earlier discharge.

Aged↗
PubMed2005

Functional outcome of unstable distal radius fractures: ORIF with a volar fixed-angle tine plate versus external fixation.

PURPOSE: The purpose of this study was to compare the outcomes of 2 treatments for unstable distal radius fractures: open reduction internal fixation (ORIF) through a volar approach with a fixed-angle implant and a standard external fixation (EF) method. METHODS: This study included patients with comminuted unstable intra-articular and extra-articular distal radius fractures treated by a single surgeon. Data were gathered retrospectively on 11 patients treated with EF who had been followed up for an average of 47 months (range, 12-84 mo). Prospective data were gathered on 21 patients who were treated with ORIF through a volar approach with a fixed-angle implant. Follow-up evaluation for this group averaged 17 months (range, 12-24 mo). The 2 groups were compared for range of motion (ROM), strength, and functional outcome as measured by the Patient Rated Wrist Evaluation (PRWE) and the Disability of the Arm, Shoulder, and Hand Questionnaire (DASH). Fracture reduction was evaluated from radiographs taken at the last follow-up visit and compared between groups. RESULTS: The mean passive wrist ROM at the final follow-up evaluation in EF patients was 59 degrees extension and 57 degrees flexion, compared with 63 degrees extension and 64 degrees flexion in patients treated with ORIF. Passive pronation/supination arc of motion was similar for the 2 groups, as were the DASH and PRWE scores. Grip strength as a percentage of the opposite wrist was significantly greater in the external fixation group, a possible consequence of longer follow-up evaluation. Final radiographic measurements for the EF group averaged 5 degrees volar tilt and 25 degrees radial inclination, with 2.2-mm ulnar-positive variance. The ORIF with volar plating group averaged 10 degrees volar tilt and 22 degrees radial inclination, with .5-mm ulnar-negative variance. Radial length and volar tilt were significantly greater for the ORIF group. The average final intra-articular step-off was significantly different, with 1.4-mm step-off in the EF group and .4 mm in the ORIF group. CONCLUSIONS: The use of ORIF with a volar fixed-angle implant resulted in stable fixation of the distal articular fragments, allowing early postsurgical wrist motion. The PRWE and DASH scores for the groups were equivalent, whereas intra-articular step-off, volar tilt, and radial length were better in the ORIF group. There were few complications, implant removal was not necessary, and early postsurgical wrist ROM was initiated without loss of reduction.

Adult↗
PubMed2005

Radial nerve excursion and strain at the elbow and wrist associated with upper-extremity motion.

PURPOSE: This study evaluated the excursion necessary to accommodate common motions of daily living and associated strain on the radial nerve. The radial nerve was evaluated at the wrist and proximal to the elbow before it bifurcated. METHODS: Five fresh-frozen transthoracic cadaver specimens (10 arms) were dissected; the radial nerve was exposed at the elbow and wrist only enough to be marked with a microsuture. Excursion was measured using a laser mounted on a caliper fixed to the bone and aligned in the direction of nerve motion. Strain was measured with a device applied to the nerve at the elbow. Nerve excursion associated with motion of the shoulder, elbow, wrist, and fingers (measured by a goniometer) was assessed at the wrist and elbow. RESULTS: An average of 4.3 mm of radial nerve excursion was required at the wrist to accommodate wrist motion from 15 degrees of radial deviation to 30 degrees of ulnar deviation and 8.8 mm was needed for elbow motion from 10 degrees to 90 degrees . The radial nerve at the elbow experienced a 28% strain associated with the same motion of flexion and extension at the elbow. When all the motions of the wrist, fingers, elbow, and shoulder were combined 9.4 mm of radial nerve excursion was required at the wrist and 14.2 mm at the elbow. CONCLUSIONS: Any factor that limits excursion at these sites could result in repetitive traction of the nerve and possibly could play a role in the pathophysiology of a mechanical neuropathy, which in the case of the radial nerve most often manifests as pain.

Body Weights and Measures↗
PubMed2005

Clonidine added to a continuous interscalene ropivacaine perineural infusion to improve postoperative analgesia: a randomized, double-blind, controlled study.

Although clonidine has been shown to increase the duration of local anesthetic action and prolong postoperative analgesia when included in single-injection nerve blocks, the only controlled investigation of the efficacy of this practice to improve analgesia for continuous perineural local anesthetic infusion failed to discern any clinically relevant benefits. For this study, we used a larger dose of clonidine in an attempt to improve analgesia. Patients (n = 20) undergoing moderately painful orthopedic surgery of the shoulder received an interscalene brachial plexus block (40 mL of mepivacaine 1.5%, epinephrine 2.5 microg/mL, and clonidine 50 microg) and a perineural catheter before surgery. After surgery, ropivacaine 0.2% or ropivacaine 0.2% plus clonidine 2 microg/mL was delivered via the catheter for 3 days (basal rate, 5 mL/h; patient-controlled bolus, 5 mL; lockout, 1 h). Investigators and patients were blind to random group assignment. The primary outcome variable was designated as the most intense pain during the day after surgery. Secondary end-points included additional pain scores, patient-controlled bolus doses, oral analgesic use, sleep quality, and catheter- or infusion-related complications. There were no statistically significant differences between groups for any of the variables investigated. We conclude that adding clonidine 2 microg/mL to a ropivacaine interscalene perineural infusion does not decrease breakthrough pain intensity the day after surgery. For the additional end-points, our negative findings are only suggestive of a lack of effect and require further study for verification.

Adrenergic alpha-Agonists↗
PubMed2005

Total shoulder arthroplasty as an outpatient procedure using ambulatory perineural local anesthetic infusion: a pilot feasibility study.

We investigated the feasibility of converting total shoulder arthroplasty (TSA) into an outpatient procedure using ambulatory interscalene perineural ropivacaine infusion. Of the patients of the first phase (n = 8) who were required to remain hospitalized for at least 1 postoperative night, 5 met discharge criteria in the recovery room. Of the subsequent patients of the second phase (n = 6), all met discharge criteria in the recovery room after surgery, and 5 were discharged directly home. For all patients, postoperative pain was well controlled, oral opioid requirements and sleep disturbances were minimal, range-of-motion consistently reached or exceeded the surgeon's expectations, and patient satisfaction was high. These results suggest that TSA may be performed on an outpatient basis using perineural local anesthetic infusion. Additional research is required to define the appropriate subset of patients and assess the incidence of complications associated with this practice before its mainstream use.

Adult↗
PubMed2005

Dysplasia epiphysealis hemimelica of the carpus.

Dysplasia epiphysealis hemimelica (Trevor's disease) is a rare developmental disorder characterized by unilateral, asymmetrical proliferation of epiphyseal cartilage. Cases involving the upper extremity are unusual. Three cases, the largest series to date, involving dysplasia epiphysealis hemimelica of the carpus, are discussed here. Two of the patients had been treated previously at other institutions where their disorders were not recognized. The purpose of this article is to present a clear description of this disorder and its natural course. A treatment algorithm is also recommended. Needless workup, treatment, and anxiety of the patient and family can be avoided by an early, accurate diagnosis.

Algorithms↗
PubMed2004

Bone-forming tumors of the upper extremity and Ewing's sarcoma.

This article presents an overview of bone-forming tumors that occur in the upper extremity. Osteoid osteoma, osteoblastoma, osteosarcoma, and Ewing's sarcoma are covered. Each tumor type is described, and suggestions are made for diagnostic workup and differential diagnosis. Locations in the upper extremity where each tumor typically occurs are given. Preferred treatment regimens and incidence of recurrence are also presented.

Arm↗
PubMed2004

Late distal biceps repair.

Distal biceps ruptures occur in well-muscled, middle-aged males. A delay in diagnosis can result in significant shortening of the biceps muscle, making late repair very difficult if not impossible. If the distal biceps tendon is not repaired, there will be a significant loss of primarily supination strength. Experience involving the late reconstruction of this muscle tendon unit is increasing. Delayed distal biceps repair requires extensive mobilization of the muscle and repair with the elbow in flexion or the use of a graft to bridge the gap from the distal end of the biceps to the radial tuberosity. Many substances have been used, including autogenous flexor carpi radialis graft, semitendinosus, and fascia lata. More recently, allograft Achilles tendon has been used. Both 1-incision and 2-incision techniques for late distal biceps tendon reconstruction using allograft Achilles tendon are presented in this paper. Late reconstruction of a distal biceps tendon using an allograft yields a good, predictable result with strength of supination returning to near normal.

Journal Article↗
PubMed2003

Anatomy and biomechanics of the acromioclavicular and sternoclavicular joints.

The acromioclavicular and sternoclavicular joints have important soft-tissue static constraints that, based on biomechanical studies, imply a great deal of stability. The infrequency of significant symptoms following dislocations of these joints certainly highlights the fact that the dynamic muscle support is also very important. In performing resections of these joints for degenerative disease, our goal should be to preserve these important ligamentous supports by minimizing the amount of bone excised, as this seems to optimize results [84]. Precise isometric reconstruction of these complex, three-dimensional ligamentous structures merits further investigation in the laboratory and clinical settings.

Acromioclavicular Joint↗
PubMed2003

Shoulder arthroplasty in the young patient.

We reviewed the performance of 22 shoulder implant arthroplasties in 19 patients age 50 or younger at surgery. Patients were evaluated by telephone interview, written questionnaire, and radiographic examination. The average age at surgery was 38.6 years, and the average follow-up was 5.6 years. Patients were grouped by disease process (rheumatoid arthritis [RA], avascular necrosis [AVN], trauma, and hemophilic arthropathy [HA]) and type of prosthesis (total vs. hemiarthroplasty). The highest scores (best shoulder function) were seen in patients with hemiarthroplasty for HA. Patients with hemiarthroplasty for trauma and AVN scored similarly, whereas those with a hemiarthroplasty for RA scored lowest. Patients with RA who had a total shoulder arthroplasty scored higher than patients with hemiarthroplasty. When patients in our population with longer follow-up were compared with those with a shorter follow-up, no downward trends in shoulder function were seen. Accelerated deterioration of function of shoulder arthroplasties was not observed in our young patient population.

Activities of Daily Living↗
PubMed2003

Continuous interscalene brachial plexus block for postoperative pain control at home: a randomized, double-blinded, placebo-controlled study.

UNLABELLED: In this study, we investigated the efficacy of patient-controlled regional analgesia for outpatients undergoing moderately painful orthopedic surgery of the shoulder. Preoperatively, patients (n = 20) received an interscalene nerve block and perineural catheter. Postoperatively, patients were discharged home with both oral opioids and a portable infusion pump delivering either 0.2% ropivacaine or 0.9% saline, determined randomly in a double-blinded manner. Daily end points included pain scores, opioid use and side effects, sleep quality, and technique complications. Ropivacaine (n = 10) infusion significantly reduced pain compared with saline (n = 10) infusion. The average pain at rest (scale: 0-10) on postoperative day 1 (median, 25th-75th percentiles) was 4.8 (4.0-5.0) for the saline group, versus 0.0 (0.0-2.0) for the ropivacaine group (P < 0.001). Oral opioid use and related side effects were also significantly decreased in the ropivacaine group. On postoperative day 1, median tablet consumption was 8.0 (6.5-9.5) and 0.5 (0.0-1.0) for the saline and ropivacaine groups, respectively (P < 0.001). Sleep disturbance scores were nearly threefold greater on the first postoperative night for patients receiving saline (P = 0.013). We conclude that after moderately painful orthopedic surgery of the shoulder, ropivacaine infusion using a portable infusion pump and an interscalene perineural catheter at home decreased pain, opioid use and related side effects, and sleep disturbances. IMPLICATIONS: This randomized, double-blinded, placebo-controlled study demonstrated that ropivacaine, infused with a portable infusion pump via an interscalene perineural catheter for 3 days at home, significantly decreased postoperative pain after orthopedic surgery of the shoulder. In addition to providing potent analgesia and increasing patient satisfaction, perineural infusion decreased opioid requirements and their associated side effects.

Aged↗
PubMedDate not supplied

Total elbow arthroplasty with massive composite allografts.

Total elbow arthroplasty is challenging when there is extensive bone loss. We studied retrospectively the long-term (mean, 6.5 years) clinical and radiographic results of 10 patients in whom 14 massive allograft-prosthetic composites were used in such clinical situations. The mean arc of active flexion/extension was 92 degrees. The Bryan-Morrey and Hospital for Special Surgery elbow scoring systems were used and revealed a modest improvement in pain and stability but a disappointing return of function, with independent self-care possible in only 3 patients, household and employment activities in 2, and recreational pursuits in 2. Three patients claimed that they were unable to use the elbow. Multiple procedures (mean, 2.2) were sometimes required to optimize the result. The 79% rate of allograft-host union is similar to that of hip and knee arthroplasty. The use of massive allografts is a reasonable alternative in salvage situations involving total elbow arthroplasty with massive bone loss.

Aged↗
PubMedDate not supplied

Total elbow arthroplasty failure due to overuse, C-ring failure, and/or bushing wear.

Semiconstrained, linked total elbow arthroplasty gives excellent functional results. However, the complication rate is relatively high, and complications are frequently significant enough to require revision surgery. The purpose of this study is to report on bushing wear and C-ring failure as a mid- to late-term complication of the Coonrad-Morrey total elbow arthroplasty. Two surgeons at different institutions treated 10 patients who had a previous Coonrad-Morrey total elbow arthroplasty and presented with C-ring and/or bushing wear. There were 8 men and 2 women. The mean age at the time of the initial total elbow arthroplasty was 54 years (range, 37-67 years). Time to revision averaged 60 months (range, 9-156 months). Common associated factors were posttraumatic arthritis (3), supracondylar nonunion (5), male sex, young age, and high activity level. A proposed mechanism of failure is postulated.

Activities of Daily Living↗
PubMedDate not supplied

Interscalene perineural ropivacaine infusion:a comparison of two dosing regimens for postoperative analgesia.

UNLABELLED: BACKGROUND AND OBJECTIVS: A continuous interscalene nerve block with a perineural infusion of ropivacaine 0.2% at 8 mL/h has been shown to provide potent analgesia following moderately painful shoulder surgery. However, this high basal rate limits infusion duration for ambulatory patients who must carry the local anesthetic reservoir. We undertook this investigation to determine if the basal rate of an interscalene perineural ropivacaine infusion could be decreased by 50% with a concurrent 200% increase in patient-controlled bolus dose without compromising infusion benefits in ambulatory patients undergoing moderately painful orthopedic shoulder surgery. METHODS: Preoperatively, patients (n = 24) received an interscalene perineural catheter and nerve block. Intraoperatively, patients received a standardized general anesthetic. Postoperatively, patients were discharged home with a portable infusion pump delivering ropivacaine 0.2% (500 mL reservoir) with a basal rate of 8 mL/h and a 2 mL patient-controlled bolus available each hour ("8/2" group, n = 12) or a 4 mL/h basal rate and 6 mL bolus dose ("4/6" group, n = 12), delivered in a randomized, double-blinded manner. RESULTS: Patients in the 4/6 group had higher baseline pain scores only on postoperative day (POD) 2 (P =.011). However, these patients also experienced an increase in breakthrough pain incidence (5.8 boluses/d v 3.2, P =.035) and intensity ("worst" pain = 8/10 v 4/10, P <.05), sleep disturbances (2.0 v 0.0, P <.001), and a decrease in analgesia satisfaction (8 v 10, P =.003). Patients in the 8/2 group exhausted their local anesthetic reservoirs after a median of 61 hours, while the 4/6 group had a median of 131 mL remaining at infusion discontinuation after a median of 75 hours (P <.001). CONCLUSIONS: Following moderately painful ambulatory shoulder surgery, decreasing an interscalene perineural ropivacaine 0.2% basal rate from 8 to 4 mL/h provides similar baseline analgesia and lengthens infusion duration, but compromises other infusion benefits.

Aged↗
PubMedDate not supplied

Joint range of motion after total shoulder arthroplasty with and without a continuous interscalene nerve block: a retrospective, case-control study.

BACKGROUND AND OBJECTIVES: Although a continuous interscalene nerve block (CISB) has been shown to provide potent analgesia after major shoulder surgery, its potential effects on postoperative rehabilitation remain uninvestigated. Therefore, this retrospective case-control study was undertaken to determine the association between CISB and joint range-of-motion after total shoulder arthroplasty (TSA). METHODS: The medical records for patients who underwent TSA at our institution in the previous 3 years were examined. Each patient with a CISB (cases) was matched with a patient without a CISB (controls) for the following variables: age, gender, and TSA type (primary v revision). Data collected included maximum shoulder elevation and external rotation (primary endpoints), along with pre- and postoperative pain scores. RESULTS: Of 134 charts reviewed, 25 cases were matched with an equal number of controls. On postoperative day 1, patients with or without a CISB achieved a median (5th-95th percentiles) of 85% (51-100) and 33% (11-56) of their surgeon-defined goal for elevation (P = .048), respectively, and attained 100% (33-100) and 17% (-81-68) for external rotation (P < .001), respectively. The median numeric rating pain score (NRS) during shoulder movement for patients with CISB was 2.0 (0.0-8.7) versus 8.5 (1.8-10.0) for patients without CISB (P < .001). Least, median, and highest resting NRS for the 24 hours after surgery were 0.0 (0.0-5.8), 1.0 (0.0-6.4), and 3.0 (0.0-9.0) for patients with CISB, respectively, versus 2.0 (0.0-7.7), 6.0 (0.3-9.6), and 8.0 (0.0-10.0) for patients without CISB (P = .030, P < .001, and P < .001 between groups, respectively). CONCLUSIONS: The day after TSA, a CISB is associated with increased shoulder range of motion, most likely resulting from the potent analgesia these nerve blocks provide.

Adult↗
PubMedDate not supplied

Total elbow arthroplasty as an outpatient procedure using a continuous infraclavicular nerve block at home: a prospective case report.

OBJECTIVE: Total elbow arthroplasty (TEA) often results in severe postoperative pain requiring hospitalization to provide potent analgesia. This prospective series investigated the feasibility of converting TEA into an ambulatory procedure using a continuous infraclavicular nerve block provided at home with a portable infusion pump. CASE REPORT: Preoperatively, patients undergoing TEA had an infraclavicular perineural catheter and peripheral nerve block placed. Postoperatively, perineural ropivacaine was delivered through postoperative day (POD) 3 to 6. Patients were discharged home when they met specific, prospectively defined criteria as early as POD 1 for the first phase and directly from the recovery room for the second phase. Of the 2 patients in the first phase who remained hospitalized for at least 1 postoperative night, both met discharge criteria in the recovery room, required no medical interventions during their admission, and were discharged home the following morning. The patient of phase 2 met discharge criteria in the recovery room and was discharged home at that time. Postoperative pain was well controlled, opioid requirements and sleep disturbances were minimal, and patient satisfaction was high for all patients. CONCLUSIONS: These cases suggest that for a subset of patients without major comorbidities, it is feasible to convert total elbow arthroplasty into an ambulatory procedure using a continuous infraclavicular nerve block as part of a multimodal analgesic regimen provided at home. Additional research is required to replicate these results in a controlled trial, define the appropriate subset of patients, and assess the incidence of complications associated with this practice before its mainstream use.

Aged↗