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Biomedical subjects

T R C Davis

Publications and source records attributed to T R C Davis.

At least 19 recordsLinked to original sources
PubMed2006

The effect of short-term dependency and immobility on skin temperature and colour in the hand.

The effects of short-term dependency and immobility on skin temperature were assessed in two experiments. In the first study, ten volunteers hung their left arm dependent and motionless while using their right hand for light office work. After 30 minutes, the dependent left hands were cooler (mean=0.9 degrees C: 95% CI=0.7-1.1) than the active right hands and exhibited a deeper colour with significantly increased green intensity (P=0.03) as assessed on digital images. In the second study, seven volunteers submerged both their hands in water at 15 degrees C for 15 minutes. The left arm was then left dependent and motionless while the right hand was placed on the table and its fingers were flexed and extended every 10 seconds. The left hands remained cooler than the right and were a median of 3.6 (range 2.9-4.5) degrees C cooler after 60 minutes. These studies demonstrate that skin temperature and colour differences between the hands, which are sometimes used to support the diagnosis of CRPS-1, can be produced and maintained by short-term immobility and dependency of the hand.

Adult↗
PubMed2006

Changes in scaphoid bone density after acute fracture.

The radiographic density of the proximal fragments of 16 scaphoid fractures was assessed on scaphoid series radiographs taken at 6 to 12 weeks. In addition, dual energy X-ray absorptiometry measurements of bone mineral density in the distal radius and proximal and distal fracture fragments were performed at 1 to 2 weeks and 6 to 12 weeks. Median reductions of 9% and 10% were observed in bone mineral density in the proximal fracture fragment and the distal radius respectively, but these did not correlate with the radiographic density of the proximal fragment. A greater median reduction in bone mineral density (27%) was observed in the distal fracture fragment and more bone loss occurred at this site when there was an apparent increase in the radiographic density of the proximal fragment (median fall of 0.23 g/cm2 versus 0.14 g/cm2). Thus, apparent increased radiographic density of the proximal fragment may be due to increased bone loss from the distal fragment.

Absorptiometry, Photon↗
PubMed2006

Intramedullary fixation of unstable metacarpal fractures.

Intramedullary stabilization of metacarpal shaft and neck fractures is a relatively simple, cost-effective, and safe technique with good published outcomes (Fig. 9); however definite advantages over other techniques of fracture stabilization, or indeed simple early mobilization in some instances, have not been clearly demonstrated. A recent publication does suggest that the technique is comparable to percutaneous transverse fixation in the context of fifth metacarpal neck fractures.

Bone Wires↗
PubMed2006

Preservation of the ulnar bursa within the carpal tunnel: does it improve the outcome of carpal tunnel surgery? A randomized, controlled trial.

BACKGROUND: It was hypothesized that preserving a layer of gliding tissue, the parietal layer of the ulnar bursa, between the contents of the carpal tunnel and the soft tissues incised during carpal tunnel surgery might reduce scar pain and improve grip strength and function following open carpal tunnel decompression. METHODS: Patients consented to randomization to treatment with either preservation of the parietal layer of the ulnar bursa beneath the flexor retinaculum at the time of open carpal tunnel decompression (fifty-seven patients) or division of this gliding layer as part of a standard open carpal tunnel decompression (sixty-one patients). Grip strength was measured, scar pain was rated, and the validated Patient Evaluation Measure questionnaire was used to assess symptoms and disability preoperatively and at eight to nine weeks following the surgery in seventy-seven women and thirty-four men; the remaining seven patients were lost to follow-up. RESULTS: There was no difference between the groups with respect to age, sex, hand dominance, or side of surgery. Grip strength, scar pain, and the Patient Evaluation Measure score were not significantly different between the two groups, although there was a trend toward a poorer subjective outcome as demonstrated by the questionnaire in the group in which the ulnar bursa within the carpal tunnel had been preserved. Preserving the ulnar bursa within the carpal tunnel did, however, result in a lower prevalence of suspected wound infection or inflammation (p = 0.04). CONCLUSIONS: In this group of patients, preservation of the ulnar bursa around the median nerve during open carpal tunnel release produced no significant difference in grip strength or self-rated symptoms. We recommend incision of the ulnar bursa during open carpal tunnel decompression to allow complete visualization of the median nerve and carpal tunnel contents.

Bursa, Synovial↗
PubMed2005

An assessment of the tensile properties and technical difficulties of two- and four-strand flexor tendon repairs.

This study compares the mechanical properties of locking Kessler and four-strand flexor tendon repairs and examines for difficulties related to technical ability. Two trainee surgeons each carried out 10 locking Kessler and 10 four-strand single-cross flexor tendon repairs on an in vitro porcine model. Outcome measures included gap formation and ultimate forces, operative time and repair bulk. Ultimate force was 81% greater for the four-strand repair compared to the Kessler (52 N, SD 5, versus 29 N, SD 6). Operating times were similar between the two techniques (Kessler 10.0 minutes, four strand 10.1 minutes). Rupture force and operating times improved slightly during the study for the Kessler repairs, but in the four strand repairs results remained stable throughout the study. We conclude that the single-cross four-strand repair tolerates superior loads yet is no more technically demanding than the modified Kessler, and can be reliably performed without additional operating time.

Animals↗
PubMed2005

Dual energy X-ray absorptiometry (DXA): can it detect acute scaphoid fractures?

This prospective study investigated whether dual energy X-ray absorptiometry (DXA) could detect acute scaphoid fractures. We blindly compared 10 normal and 10 fractured scaphoid images produced with a new technique of DXA scan analysis. This measured and plotted the density of the scaphoid throughout its length, producing a linear graph of the scaphoids' density instead of a single area (g/cm2) measurement of bone density. These new plots only detected six of the 10 fractures and suggested that four of the normal controls were fractured. Thus, this technique of DXA scan analysis is neither sensitive nor specific for the detection of acute scaphoid fractures.

Absorptiometry, Photon↗
PubMed2005

Dorsal fracture-dislocation of the proximal interphalangeal joint: a comparative study of percutaneous Kirschner wire fixation versus open reduction and internal fixation.

Nineteen patients with a dorsal fracture-dislocation of the proximal interphalangeal joint of a finger were treated with either closed reduction and transarticular Kirschner wire fixation (eight cases) or open reduction and internal fixation, using either one or two lag screws (six cases) or a cerclage wire (five cases). At a mean follow-up of 7 (range 6-9) years, most patients reported satisfactory finger function, even though some of the injuries healed with proximal interphalangeal joint incongruency (seven cases) or subluxation (four cases). Those treated by open reduction complained of more "loss of feeling" in the affected finger and those specifically treated by cerclage wire fixation reported more cold intolerance and had a significantly larger fixed flexion deformity (median, 30 degrees : range 18-38 degrees ) and a smaller arc of motion (median, 48 degrees : range 45-60 degrees ) at the proximal interphalangeal joint, despite having the best radiological outcomes. Closed reduction and transarticular Kirschner wire fixation produced satisfactory results, with none of the eight patients experiencing significant persistent symptoms despite a reduced arc of proximal interphalangeal joint flexion (median=75 degrees ; range 60-108 degrees ). The results of this relatively simple treatment appear at least as satisfactory as those obtained by the two techniques of open reduction and internal fixation, both of which were technically demanding.

Adult↗
PubMed2005

Partial union of acute scaphoid fractures.

Sixty-six patients with acute scaphoid fractures were treated non-operatively in a below elbow plaster for 8 to 12 weeks and underwent CT scans along the longitudinal axis of the scaphoid at 12 to 18 weeks. These scans showed that 14 fractures had not united and that 30 had united throughout the whole cross-section of the scaphoid. The other 22 had partially united with bridging trabeculae in some areas of the cross-section. These 22 partial unions were graded as 0% to 24% union (0 cases), 25% to 49% union (5 cases), 50% to 74% union (7 cases), and 75% to 99% union (10 cases). The 12 patients who had less than 75% fracture union were followed-up further and nine underwent another CT scan at 23 to 40 weeks after the initial injury. These showed union across the whole of the cross-section of the fracture in seven cases and 75% to 99% union in the other two cases, who had full and painless wrist function. We conclude that partial union of the scaphoid is a common occurrence but, in most cases, it progresses to full union without the need for prolonged plaster immobilization.

Adult↗
PubMed2004

Work practices and histopathological changes in the tenosynovium in carpal tunnel syndrome in men.

The aim of this prospective study was to assess whether the fibrous thickening of the carpal tunnel tenosynovium is influenced by working practices. We did this by investigating 50 men (58 hands) with idiopathic carpal tunnel syndrome, who were undergoing carpal tunnel decompression. Occupational history, including vibration tool exposure, and presence of callosities and/or ingrained dirt on hands was recorded at the time of surgery. The flexor tenosynovium was biopsied, and assessed histologically by an observer blinded to occupational history. Occupational group, age, weight and smoking showed no significant association with fibrous tenosynovial thickening. There was also no significant association between fibrous tenosynovial thickening and the presence of hand callosities/in-grained dirt or regular use of vibration tools. Thus no association was found between heavy occupational hand usage and the development of fibrous tenosynovial thickening around tendons within the carpal tunnel.

Adult↗
PubMed2004

A prospective study of the treatment of fractures of the little finger metacarpal shaft with a short hand cast.

This prospective study describes the use of a short hand cast, which leaves the finger metacarpophalangeal and wrist joint free, for angularly displaced little finger metacarpal shaft fractures which require reduction. Twenty-seven patients with a mean age of 25 (range, 16-39) years with little finger or combined ring and little finger displaced metacarpal shaft fractures were prospectively recruited. All were treated by closed fracture reduction and immobilization in the cast. Patients were followed up at 1 week, 4 weeks, and between 6 and 12 months. At each of these follow-up visits posteroanterior and lateral radiographs of the metacarpals were performed to assess angulation of the fracture. The mean initial angulation of the 17 little finger metacarpal fractures with complete follow up was 40 degrees (range, 20-60 degrees ). Their mean final angulation at 6 to 12 months was 8 degrees. The fracture reduction was lost in three patients in whom the final angular deformities were 15 degrees (one patient) and 20 degrees (two patients). Journal of Hand Surgery (British and European volume, 2004)

Adolescent↗
PubMed2004

Gadolinium enhanced MR assessment of proximal fragment vascularity in nonunions after scaphoid fracture: does it predict the outcome of reconstructive surgery?

This study investigated whether the outcome of bone graft and internal fixation surgery for nonunion of scaphoid fractures could be predicted by gadolinium-enhanced MR assessments of proximal fragment vascularity. Sixteen established scaphoid fracture nonunions underwent gadolinium-enhanced MR scanning before surgical treatment with bone grafting and internal fixation. No relationship was found between MR enhancement and the outcome of surgery. Union was achieved in eight of the 12 nonunions with more than 50% enhancement, and three of the four with less than 50% enhancement, of the proximal pole. Furthermore, union was achieved in both of the nonunions which had less than 25% enhancement of the proximal pole. We conclude that enhanced MR assessments of the vascularity of the proximal fragment of a scaphoid fracture nonunion do not accurately predict the outcome of reconstructive surgery.

Adult↗
PubMed2004

The Consolidated Standards of Reporting Trials (CONSORT): better presentation of surgical trials in the Journal of Hand Surgery.

To assure readers that study results are scientifically valid, the methods of a clinical trial should be described adequately. Since randomization, blinding, and intention-to-treat-analysis are major bias-reducing techniques, these aspects should be reported most accurately. The Consolidated standards of reporting trials (CONSORT) are recommendations to improve the reporting of trials. CONSORT requires that trial authors describe basic methodological aspects that readers need to appraise the strengths of reported clinical trials. This article presents the CONSORT recommendations and explains some of their main aspects. From now on, the Journal of Hand Surgery will use CONSORT to assist authors of randomized controlled trials in improving the description of their studies. We believe that this decision increases the scientific validity of study reports and helps readers when critically appraising articles.

Data Interpretation, Statistical↗
PubMed2004

MRI and plain radiography in the assessment of displaced fractures of the waist of the carpal scaphoid.

We treated 50 patients with fractures of the waist of the scaphoid in a below-elbow plaster cast for up to 13 weeks. Displacement of the fragments was assessed independently by two observers using MRI and radiographs performed within two weeks of injury. The MRI assessments showed that only the measurement of sagittal translation of the fragments and an overall assessment of displacement had satisfactory inter- and intra-observer reproducibility and revealed that nine of the 50 fractures were displaced. Only three of the 49 fractures with adequate follow-up failed to unite, and all were displaced with more than 1 mm of translation in the sagittal plane. If the MRI assessment of displacement of the fracture was used as the measurement of choice, assessment of displacement on the initial scaphoid series of radiographs showed a sensitivity of between 33% and 47% and a positive predictive value of between 27% and 86%. Neither observer was able correctly to identify more than 33% to 47% of the displaced fractures from the plain radiographs. Although the overall assessment of displacement and gapping and translation in the coronal plane on the plain radiographs influenced the rate of union, none of these parameters identified all three fractures which failed to unite. We conclude that the assessment of displacement of scaphoid fractures on MRI can probably be used to assess the likelihood of union although the small number of nonunions limits the power of the study. In contrast, the assessment of displacement on routine radiography is inaccurate and of less value in predicting union.

Casts, Surgical↗
PubMed2003

A prospective randomized controlled study of fixation of long oblique and spiral shaft fractures of the proximal phalanx: closed reduction and percutaneous Kirschner wiring versus open reduction and lag screw fixation.

Patients with an isolated spiral or long oblique fracture of the proximal phalanx were randomized into two groups. One was treated by closed reduction and Kirschner wire fixation and the second treated by open reduction and lag screw fixation. An independent observer assessed function, pain, movement, grip strength and intrinsic muscle function. X-rays were assessed for malunion. Thirty-two patients were entered the study and 15 in the Kirschner wire and 13 in the lag screw group were reviewed at a mean follow-up of 40 months. There was no significant difference in the functional recovery rates or in the pain scores for the two groups. X-rays showed similar rates of malunion and there were no statistically significant differences in range of movement or grip strength.

Adolescent↗
PubMed2002

The rapid exchange grip strength test and the detection of submaximal grip effort.

This study assessed the reliability of the rapid exchange grip test for detecting submaximal grip effort, particularly evaluating its performance with motivated subjects with genuine hand weakness secondary to pain. Fifty normal participants performing with maximum effort then feigning hand weakness and 50 patients recovering from carpal tunnel surgery were studied. The results showed that the dynamic measure of grip strength equaled or exceeded the static measure in 28% of maximally performing participants (72% specificity), 58% of the carpal tunnel decompression patients (42% specificity), and 74% of participants giving submaximal grip effort (74% sensitivity). Sensitivities and specificities for other criteria of a positive test were also determined. Our findings suggest that the rapid exchange grip strength test cannot reliably detect voluntary submaximal effort.

Adult↗
PubMed2002

Scaphoid nonunion: treatment with a pedicled vascularized bone graft based on the 1,2 intercompartmental supraretinacular branch of the radial artery.

Pedicled vascularized bone grafts (Zaidemberg's technique) were used to treat 22 established scaphoid fracture nonunions, 16 of which were found to have avascular proximal poles at surgery. After a follow-up of 1-3 years, only six (27%) of the 22 fracture nonunions had united. Only two of the 16 nonunions with avascular proximal poles united, compared with four of the six nonunions with vascular proximal poles. We conclude that this technique of pedicled vascularized bone grafting may not improve the union rate for scaphoid fracture nonunions with avascular proximal pole fragments.

Adult↗