Mechanical stability of the AO internal spinal fixation system compared with that of the Hartshill rectangle and sublaminar wiring in the management of unstable burst fractures of the thoracic and lumbar spine.

STUDY DESIGN: A radiographic comparison of the mechanical efficacy of the Hartshill rectangle and that of the AO internal spinal skeletal fixation systems in the management of unstable burst fractures of the thoracic and lumbar spine. OBJECTIVES: To study the restoration and maintenance of normal spinal anatomy after open reduction and internal fixation of unstable burst fractures of the thoracic and lumbar spine. SUMMARY OF BACKGROUND DATA: There are laboratory studies documenting the biomechanical advantages of the AO internal spinal skeletal fixation systems. There have been no previous comparisons of the internal spinal skeletal fixation system with the Hartshill rectangle and sublaminar wiring in matched patient groups. METHODS: Radiographs obtained before surgery, immediately after surgery, and at 2 years after surgery were used to assess the restoration and maintenance of normal spinal anatomy in 14 patients who had undergone stabilization with the Hartshill System and in 12 patients who had undergone internal fixation using the AO internal spinal skeletal fixation system. RESULTS: The initial restoration of normal spinal anatomy was good using both systems. However, on examination 2 years after surgery, it was found that the AO system provided significantly superior maintenance of both middle (P < 0.01) and anterior column anatomy (P < 0.001). CONCLUSION: The AO internal spinal skeletal fixation systems is associated with significantly superior maintenance of spinal anatomy 2 years after surgery.

The effects of an Electronic Medical Record on patient care: clinician attitudes in a large HMO.

OBJECTIVE: The purpose of this study is to examine the attitudes of clinicians in a large HMO toward the effect of an outpatient Electronic Medical Record system on the quality of patient care. Attitudes toward a Results Reporting system and an online charting and ordering system are also compared. DESIGN: A cross-sectional study was performed using a survey of Kaiser Permanente Northwest clinicians. In addition, interviews were conducted with the physician leaders of the clinical departments at Kaiser Permanente Northwest. MEASUREMENTS: Clinician attitudes are measured regarding the effects of a Results Reporting system and an online charting and ordering system on the overall quality of patient care and other care-related indices. RESULTS: Most clinicians feel that the outpatient Electronic Medical Record has improved the overall quality of patient care, with 72% reporting an improvement with the use of the Results Reporting system, and 60% reporting an improvement with the use of the online charting and ordering system. On average, clinicians feel that the EMR has also improved the quality of the patient-clinician interaction, the ability to coordinate the care of patients with other departments, the ability to detect medication errors, the timeliness of referrals, and the ability to act on test results in a timely fashion. CONCLUSION: Clinicians perceive an improvement in patient care as a result of using an outpatient Electronic Medical Record system. Clinicians have higher opinions, however, of the effects of a Results Reporting system compared to an online charting and ordering system.

Surgical release of knee flexion contractures in myelomeningocele.

We report the results of a prospective study of the surgical release of 45 knee flexion contractures in 28 patients with myelomeningocele. The neurosegmental level was thoracic in ten patients, L1/2 in one, L3/4 in 11, and L5/S1 in six. In walkers the indication for surgery was a fixed flexion contracture impeding walking, and in non-walking patients it was a flexion contracture impeding transfers or sitting balance, or likely to do so with increasing deformity. The mean age at surgery was 6.4 years (3 to 21) and the mean period of follow-up 13 years (4 to 20). The mean knee flexion contracture before surgery was 39 (25 to 70) which improved to 5 degrees at maximum correction and to 13 degrees at latest follow-up. We conclude that surgical release of knee flexion contractures in myelomeningocele improves gait in all children who walk, particularly those with low lumbar lesions. Recurrence of knee flexion contractures after surgical release is most common in those with thoracic lesions who do not achieve independent walking.

Radiologic study of the accuracy of a tibial intramedullary cutting guide for knee arthroplasty.

Twenty-one caucasian, adult cadaveric tibiae were prepared as for knee arthroplasty using an intramedullary cutting guide. The instrumentation was used to produce slots in the proximal tibia into which Kirschner wires were placed as radio-opaque markers for subsequent anteroposterior and lateral radiographs. The anatomic axis of the tibia and lines perpendicular to the wire markers were drawn on the radiographs and the angle between the two lines was measured to assess the accuracy of the cuts. Seventy-one percent of the tibial cuts were found to be within 2 degrees of the anatomic axis on the anteroposterior radiograph (mean, 2.1 degrees), while on the lateral radiograph, 81% of the cuts were within 2 degrees (mean, 1.8 degrees). There was a significant tendency to position the bone cuts in varus (P < .05), although this did not correlate with varus or valgus deformity of the bones. There was no consistent tendency to anterior or posterior tilt on the lateral radiograph (P > .05). The results compare favorably with those obtained from a specialist unit using an extramedullary alignment system. The authors conclude that the tibial intramedullary guide can lead to preparation of the proximal tibia for knee arthroplasty as accurately as the conventional extramedullary system.

The perceived relationship between neck symptoms and precedent injury.

A questionnaire survey of 328 hospital employees was used to establish the general prevalence of neck symptoms related to everyday activities in a representative population of working society. The response rate was 92 per cent. Of the study population of 302, 54 had suffered neck injury, and of this group, 43 (80 per cent) had some neck discomfort during or after performing normal everyday tasks. Of the symptomatic cases, only seven (16 per cent) admitted that they had suffered from some neck symptoms before the injury, whilst 36 (84 per cent) attributed all of their neck symptoms to the injury sustained. Of the total population, 248 had not suffered a neck injury and of this group 84 (34 per cent) suffered some neck discomfort during or after performing normal everyday tasks. The chi 2 test was used to test the null hypothesis that the sub-group attributing their symptoms to injury, in whom only 16 per cent acknowledged pre-existent neck symptoms, was derived from the same population as the group who had not suffered any definite neck injury, and yet were still troubled with some neck symptoms in 34 per cent of cases. This hypothesis was rejected (P < 0.01), indicating that there was a significant difference between these two groups. We conclude that some individuals who suffer a neck injury do not recall that they suffered some minor neck symptoms before injury. The statistical analysis and alternative possible explanations are discussed. Our conclusions may be of medico-legal importance in cases where compensation is being sought.

Should Esmarch bandages be used for exsanguination in knee arthroscopy and knee replacement surgery? A prospective trial of Esmarch exsanguination versus simple elevation.

In order to compare the adequacy of exsanguination produced by Esmarch bandages with that produced by simple elevation for 2 min, a blind randomized prospective trial was undertaken in 50 patients undergoing total knee replacement surgery and 50 patients undergoing knee arthroscopy surgery. The mean blood loss during total knee replacement was significantly greater in the group exsanguinated by elevation (P < 0.01). The haematocrit of samples of the arthroscopy drainage fluid was consistently less than 1%, irrespective of the method of exsanguination used. None of the operating surgeons reported that they considered that either knee replacement surgery or arthroscopic knee surgery had been made any more difficult by the use of elevation as a means of exsanguination. In view of the established risks of using Esmarch bandages, we would suggest that the use of this method of exsanguination in these fields of orthopaedic surgery is not justified.

Avoiding nerve damage during elbow arthroscopy.

To define the anatomical relationships of the nerves to the common arthroscopy portals at the elbow an arthroscope was introduced into 20 cadaver elbows and the positions of the nerves were then determined by dissection. In all cases the posterior interosseous nerve lay close to the radiohumeral joint and to the anterolateral portal. Pronation of the forearm displaced the nerve away from the arthroscope. The median nerve passed consistently within 14 mm of the arthroscope when it was introduced through the anteromedial portal. The branches supplying the superficial forearm flexor muscles were at risk.

Laboratory comparison of the cannulated Herbert bone screw with ASIF cancellous lag screws.

The compression produced by and the resistance to pullout of the 6.5 mm cannulated Herbert screw were compared with those of ASIF headed screws. The latter were tested with and without washers and in the following sizes: 4.5 mm cortical, 6.5 mm cancellous with a 16 mm threaded segment, and 6.5 mm cancellous with a 32 mm threaded segment. Polyurethane foam was used as a substitute for cancellous bone and ASIF artificial bone for corticocancellous bone. The compression produced by a cancellous lag screw with a washer was significantly greater than that produced by a Herbert screw of equivalent size (p < 0.05). When the screws were tested using the corticocancellous composite the ASIF cancellous screw without a washer produced significantly greater compression (p < 0.05); when used with a washer the difference was highly significant (p < 0.001). The dual pitch Herbert screw is not appropriate for the management of fractures in which compression is of greater importance than the need to avoid prominence of the screw head.

Hip fracture patients may be vitamin B6 deficient. Controlled study of serum pyridoxal-5'-phosphate.

Deficiency of vitamin B6 in rats may result in defective bone formation, possibly due to decreased activity of the enzyme ornithine decarboxylase which requires pyridoxal-5'-phosphate (PLP) as a co-factor and is responsible for production of intracellular putrescine, a metabolic regulator. We studied 3 groups of patients (62 fit ambulant out-patients, 21 elective arthroplasty patients, and 20 hip fracture patients) and assayed their PLP status by high performance liquid chromatography. The reference range derived from the out-patients was 13-106 nmol/L. 3 of the arthroplasty group and 10 of the fracture group had serum PLP concentrations less than 13 nmol/L (P < 0.01). We conclude that PLP may be an etiologic factor in hip fracture by virtue of its role in the activity of a key regulatory protein.

A safe, reliable method of carpal tunnel injection.

The injection of steroid preparations into the carpal canal is a recognized practice in the management of carpal tunnel syndrome. This procedure is associated with a risk of temporary or permanent damage to the median nerve. We present a new method of carpal tunnel injection based on anatomic dissections. We have used this technique successfully for more than 10 years, and there have been no cases of median nerve injury.

The Sheffield splint for controlled early mobilisation after rupture of the calcaneal tendon. A prospective, randomised comparison with plaster treatment.

Forty patients with acute complete rupture of the calcaneal tendon were managed conservatively and randomly allocated to treatment groups using either cast immobilisation for eight weeks, or cast immobilisation for three weeks, followed by controlled early mobilisation in a Sheffield splint. The splint is an ankle-foot orthosis which holds the ankle in 15 degrees of plantar flexion, but allows some movement at the metatarsophalangeal joints. It is removed to allow controlled movement during physiotherapy. Patients treated with the splint regained mobility significantly more quickly (p less than 0.001) and preferred the splint to the plaster cast. The range of dorsiflexion at the ankle improved more rapidly after treatment in the splint (p less than 0.001), and patients were able to return to normal activities sooner. Recovery of the power of plantar flexion was similar in the two treatment groups, and no patient had excessive lengthening of the tendon. One re-rupture occurred in each group.

When should a synthetic casting material be used in preference to plaster-of-Paris? A cost analysis and guidance for casting departments.

An accurate cost analysis of the use of one of the new synthetic casting materials (Cellacast) compared with plaster-of-Paris (Gypsona) was undertaken over a 3-month period in the fracture clinic of Cardiff Royal Infirmary. The mean duration of usage before failure for synthetic forearm, scaphoid and below-knee casts was found to be approximately twice that of plaster casts. The use of synthetic casting materials was found to be cost-effective in situations where there was thought to be a high probability that structural failure of the cast would occur. Guidelines for the use of plaster-of-Paris and synthetic casting materials are presented.

Risk of deep infection with intramedullary nailing following the use of external fixators.

A retrospective review was carried out to assess the incidence of deep infection occurring when intramedullary nailing was performed following the use of an external fixator. Three groups of patients were identified: group 1 in which the external fixator was used in initial fracture management (ten cases, nine patients), group 2 in which the external fixator was used in the management of established non-union (seven cases, seven patients), and group 3 in which the external fixator was used in limb lengthening procedures (eight cases, eight patients). All the 25 cases reviewed had clinical evidence of pin track infection before removal of the external fixator. After removal of the fixator it is our normal policy to wait for the pin sites to become dry before performing intramedullary nailing. In only one case, where there was a history of preceding recrudescent osteomyelitis, was there evidence of deep infection being reactivated following intramedullary nailing. We therefore conclude that pin track infection does not seem to be a contraindication to the subsequent use of an intramedullary nail, providing that underlying active osteomyelitis is not present. A delay of 7 to 14 days after removal of the fixator is recommended. Some problems experienced during nailing are highlighted, and solutions proposed.

Fatal pulmonary fat embolism during total hip replacement due to high-pressure cementing techniques in an osteoporotic femur.

High-pressure cementing techniques, involving the use of a cement gun and cement restrictor, placed within the femoral medullary cavity, are commonly used to secure the femoral component of hip arthroplasties. Such techniques have been shown to be important in maintaining the integrity of the bone-cement interface and also the integrity of the cement itself. This case report illustrates that such techniques are not without complications.

Autoantibodies to GBM and neutrophil cytoplasm in rapidly progressive glomerulonephritis.

The incidence of autoantibodies to glomerular basement membrane (AGBMA) and neutrophil cytoplasmic antigens (ANCA) in the initial sera of 889 consecutive patients with a suspected diagnosis of rapidly progressive glomerulonephritis, was determined by prospective study. Forty-seven (5%) were positive for AGBMA alone, 246 (28%) were positive for ANCA alone, 576 (65%) had neither autoantibodies while 20 (2%) had both. Clinical and pathological data collected from patients with both autoantibodies suggested the coexistence of anti-glomerular basement membrane disease and systemic vasculitis. Together, assays for AGBMA and ANCA are important in the diagnosis and management of rapidly progressive glomerulonephritis and may help its further classification.

Problems and pitfalls in assessing human T-lymphocyte mutant frequencies.

The measurement of 6-thioguanine-resistant frequencies in human T-lymphocytes has been used to quantitate the in vivo HPRT mutant frequency. The data so far indicate a large variability in normal healthy individuals. The reliability with which wells are identified for clonal growth in the assay was investigated using 5 different methods of scoring: visual scoring, uptake of [3H]thymidine (either by cut off point or by statistical analysis), cell count and cytogenetic analysis. None of these methods presented a viable means of scoring the assay. An examination of the statistical precision of the assay under the limitations imposed by the experimental conditions leads to the conclusion that there is a large inherent error associated with the estimated mutant frequencies. Analysis of the T-lymphocyte subpopulations by cell surface monoclonal antibodies also leads us to believe that the observed mutant frequencies may not be representative of the true in vivo mutant frequencies. If the assay is to be used as a sensitive screen for individual or population exposure to possible mutagens, a closer understanding of the biology of the assay is indicated, and a comprehensive reevaluation of the methodology required. The utility of the system for studying qualitative aspects of human mutagenesis is not in doubt.

Prospective study of radioimmunoassay for antibodies against neutrophil cytoplasm in diagnosis of systemic vasculitis.

The diagnosis and management of Wegener's granulomatosis and microscopic polyarteritis are complicated by the lack of specific diagnostic tests. The diagnostic performance of a solid-phase radioimmunoassay, which detects the autoantibodies against neutrophil cytoplasm present in these disorders, was assessed in a prospective study of patients with suspected vasculitis and/or rapidly progressive nephritis. The assay had a sensitivity and specificity of 96% when carried out in combination with a specific inhibition stage and indirect immunofluorescence staining of alcohol-fixed normal neutrophils.