An analysis of blood management in patients having a total hip or knee arthroplasty.

Three hundred and thirty orthopaedic surgeons in the United States participated in a study of transfusion requirements associated with total joint arthroplasty. A total of 9482 patients (3920 patients who had a total hip replacement and 5562 patients who had a total knee replacement) were evaluated prospectively from September 1996 through June 1997. Of those patients, 4409 (46 percent [57 percent of the patients who had a hip replacement and 39 percent of the patients who had a knee replacement]) had a blood transfusion. Two thousand eight hundred and ninety patients (66 percent) received autologous blood, and 1519 patients (34 percent) received allogenic blood. Ordered logistic regression analysis showed the most important predictors of the transfusion of allogenic blood to be a low baseline hemoglobin level and a lack of predonated autologous blood. Preoperative donation of autologous blood decreases the risk of transfusion of allogenic blood; however, inefficiencies in the procedures for obtaining autologous blood were identified. Sixty-one percent (5741) of the patients had predonated blood for autologous transfusion, but 4464 (45 percent) of the 9920 units of the predonated autologous blood were not used. Primary procedures and revision total knee arthroplasty were associated with the greatest number of wasted autologous units. Of the 5741 patients who had predonated blood, 503 (9 percent) needed a transfusion of allogenic blood. The frequency of allogenic blood transfusion varied with respect to the type of operative procedure (revision total hip arthroplasty and bilateral total knee arthroplasty were associated with the highest prevalence of such transfusions) and with a baseline hemoglobin level of 130 grams per liter or less. Transfusion of allogenic blood was also associated with infection (p < or = 0.001), fluid overload (p < or = 0.001), and increased duration of hospitalization (p < or = 0.01). These latter findings warrant further evaluation in controlled studies.

A case of germinal center formation by CD45RO T and CD20 B lymphocytes in rheumatoid arthritic subchondral bone: proposal for a two-compartment model of immune-mediated disease with implications for immunotherapeutic strategies.

In rheumatoid arthritis (RA) disease activity occurring as joint destruction of cartilage and bone is thought to be driven by inflammatory reactions which are initiated by exogenous microbial mechanisms and perpetuated by endogenous autoimmune mechanisms. According to the synovial model of RA, these reactions originate in the adjacent synovial tissues. The following set of observations is presented herein to suggest an alternate model involving subchondral bone. Lymphocytic infiltrates accompanied by immunoglobulin deposits were identified in rheumatoid subchondral bone near areas of cartilage undergoing destruction by local subchondral inflammation. CD45RO T lymphocytes also were identified with these infiltrates as well as with CD20 B lymphocytes in an area of subchondral bone containing a well-organized germinal center. Analysis of extracts of rheumatoid subchondral bone revealed a high incidence of autoantibodies directed against type II collagen, the major protein constituent of cartilaginous tissue. Analysis of IgG subclass and cyanogen bromide peptide specificity revealed a pathogenic subset of these autoantibodies. A passive transfer study utilizing similar antibodies from collagen arthritic animals confirmed that such autoantibodies would have the potential of contributing directly to disease activity observed in rheumatoid subchondral bone. These studies suggest that (i) subchondral bone may be playing an active role in RA as a local site of immune-mediated disease activity and (ii) basic and therapeutic studies aimed at understanding and eventually controlling RA should be diversified to include the study of not only synovial tissue, but also subchondral bone as a local source of the antigenic, cellular, and humoral immune components of joint destruction.

Eccentric and concentric muscle performance in patients with spastic paresis secondary to motor neuron disease. A preliminary report.

This study investigated the potential value of eccentric (ECC) and concentric (CONC) isokinetic testing for quantifying motor deficit in patients with spastic paresis secondary to motor neuron disease. We hypothesized that, at a moderately fast (120 degrees s-1) angular velocity, spastic patients would demonstrate different ECC-CONC torque relationships from healthy controls or patients with non-spastic neuromuscular disorders. Eleven patients with motor neuron disease having clinical evidence of spasticity, and 11 disease-control patients (with non-spastic disorders, e.g. lower motor neuron disease or myopathy) underwent isokinetic testing. One healthy subject was matched to each of the 22 patients. The average torque generated during maximal voluntary ECC and CONC knee flexion (KF) and extension (KE) was measured using an isokinetic dynamometer (Kin-Com). Reliability was established (all ICC > or = 0.97) for patient torque measurements. Relative strength (% of control subject torque) in spastic patients was significantly higher for ECC than for CONC actions in both KF and KE; conversely, in non-spastic disease-control patients relative strength was not affected by the type of muscle action. The ECC/CONC average torque ratios for KE and KF at 120 degrees s-1 were significantly greater in spastic patients than controls, but did not differ from controls in non-spastic patients. In spastic patients the ECC-CONC imbalances were related to ambulatory dysfunction. In four spastic patients followed with serial testing, the disproportion between ECC and CONC voluntary capacity persisted over time.(ABSTRACT TRUNCATED AT 250 WORDS)

Enoxaparin: the low-molecular-weight heparin for prevention of postoperative thromboembolic complications.

OBJECTIVE: To introduce readers to a new low-molecular-weight heparin (LMWH) product, enoxaparin. The chemistry, pharmacology, pharmacodynamics, clinical efficacy in thromboembolic prophylaxis following surgery, and adverse effects are reviewed. DATA SOURCES: A MEDLINE search of the English-language literature was used to identify relevant literature. STUDY SELECTION: A focus was placed on human clinical studies with well-accepted measures of antithrombotic efficacy endpoints, i.e., venography and ultrasonography. Emphasis was on pharmacologic and pharmacokinetic studies conducted in humans. DATA EXTRACTION: Most data were extracted from double-blind, controlled clinical studies. Other study designs were accepted if the results were believed to be significant. Pharmacology and pharmacokinetic data were selected from studies with exceptional design conducted in humans. DATA SYNTHESIS: Enoxaparin is a polysaccharide chain produced by the depolymerization of heparin. In comparison with heparin, which has an average molecular weight of 12,000-15,000 daltons, the average molecular weight of enoxaparin is approximately 4500 daltons. Enoxaparin does not form a complex with antithrombin III and thrombin as extensively as does heparin; however, the anti-Xa activity of enoxaparin is similar. The significance of this fact is an enhancement of antithrombotic activity and clinical efficacy. Trials comparing enoxaparin with other thromboembolic prophylaxis techniques are ongoing. CONCLUSIONS: Thromboembolism remains one of the major complications of all surgical procedures. Attempts have been made throughout the last century to develop the most effective means to prevent this complication. Clinical studies performed throughout the world have shown that enoxaparin is superior or equivalent to other antithrombotic agents, including heparin, in preventing the formation of venous thromboembolism. In addition, enoxaparin appears to possess an equivalent or lower incidence of bleeding complications when compared with heparin prophylaxis. Enoxaparin is expected to be joined by other LMWH products in the future. As a result, the methods of providing effective prophylaxis against thromboembolic complications is expected to change in the coming years.

Eccentric muscle performance of elbow and knee muscle groups in untrained men and women.

Maximal voluntary eccentric (ECC) and concentric (CON) capacity of knee and elbow muscle groups was investigated in healthy untrained men (N = 40) and women (N = 50), 21-67 yr of age. Purposes of the study were to describe torque-velocity and ECC-CON relationships, and to compare these relationships among muscle groups and between genders. Average torque was measured at angular velocities of 30 degrees and 120 degrees.s-1 from knee flexor (KF), knee extensor (KE), and elbow flexor (EF) muscle groups unilaterally, using an isokinetic protocol including gravity compensation. Data were analyzed using ANOVA procedures, and a significance level of 0.01 was used for all hypothesis testing. Torque-velocity relationships were similar for each muscle group and gender; i.e., ECC average torque did not change as a function of velocity and CONC torque decreased as angular velocity increased. Women generated greater ECC relative to CONC torque than men in upper and lower extremity muscle groups. Muscle groups differed in ECC relative to CONC capacity in both men and women, with ECC/CONC ratios being greater for KE and EF than KF. In all muscle groups, the magnitude of ECC-CONC differences increased as angular velocity increased. Genders differed in relative strength balance between muscle groups, with men exhibiting greater KF/KE and EF/KF torque ratios than women for both ECC and CONC actions. Results of this study contribute to the body of women.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of photographic and transparency-based methods for measuring wound surface area.

BACKGROUND AND PURPOSE: The purposes of this study were to compare test-retest reliability of measurements obtained by the use of a photographic method and those obtained by the use of a transparency method and to compare wound surface area (WSA) measurements obtained by these two methods. SUBJECTS: Twenty inpatients (18 male, 2 female), aged 31 +/- 16 years (mean +/- SD), participated in the study. METHODS: Tracings of ulcer borders generated by the photographic and transparency methods were digitized to obtain WSA measurements. To assess intrarater reliability for each method, 5 ulcers were measured on two occasions. The magnitude of WSA measurements obtained by the photographic and transparency methods was compared in 22 ulcers measured on one occasion and in 16 ulcers measured at 5-day intervals for 20 days. RESULTS: Intraclass correlation coefficients (ICCs) were high (ICC = .99) for each method, indicating reliability of measurements. The WSA measurements did not differ between photographic and transparency methods, either at one occasion or over a 20-day period. CONCLUSION AND DISCUSSION: We concluded that the photographic and transparency methods, as applied in this study of ulcers, provided equivalently reliable measurements and that WSA measurements obtained by the two methods were equivalent. The transparency method was more economical than the photographic method in terms of time and equipment requirements.

Seated lumbar/pelvic alignment. A comparison between spinal cord-injured and noninjured groups.

It has been postulated that loss of voluntary trunk stability, combined with the posture imposed by the configuration of the wheelchair seat, biomechanically necessitates that a person with diminished trunk control assume an abnormal sitting posture. This posture is characterized by a long, "C"-shaped kyphotic thoracolumbar spine, an extended cervical spine, a flattened lumbar spine, and a posteriorly tilted pelvis. If lateral trunk deformities are present, trunk imbalance and pelvic deformities in the coronal (frontal) plane can exist. This study has investigated the spinal/pelvic postural alignment of a limited sample of seated spinal cord-injured people and compared the results to a similar sample of able-bodied individuals seated in the same standardized positions. The results suggests that there are distinct differences in the spinal/pelvic alignment between the two study groups. These differences and the movements that take place in the pelvic structures during active wheelchair sitting have implications relative to pressure sore prevention and postural management.

Failure of centralization of the fibula for congenital longitudinal deficiency of the tibia.

Between 1962 and 1983, fourteen patients (twenty knees) had centralization of the fibula for congenital longitudinal deficiency: tibial, complete. Eleven of the twenty index procedures were performed on patients who were one year old or less. A progressive flexion deformity of the knee developed after all twenty index procedures. Twenty-six secondary procedures were needed, including disarticulation at the knee, posterior release, extension osteotomy, femorofibular arthrodesis, and biceps-to-quadriceps transfer, and one patient had a second attempt at centralization of the fibula. The duration of follow-up after the initial centralization of the fibula ranged from four years to twenty-two years and seven months (average, twelve years and four months). Seven patients (eight limbs) in whom the index procedure resulted in failure had a satisfactory result after disarticulation at the knee. The patients who did not have secondary disarticulation at the knee are also considered to have had a failed index procedure because they had a flexion deformity at the latest follow-up. Attempts to reconstruct the knee joint by centralization of the fibula are not warranted for patients who have congenital longitudinal deficiency: tibial, complete. Early disarticulation at the knee and fitting with a prosthesis, with close follow-up, is the treatment of choice.

Efficacy of high voltage pulsed current for healing of pressure ulcers in patients with spinal cord injury.

The purpose of this study was to assess the efficacy of high voltage pulsed direct current (HVPC) for healing of pressure ulcers in patients with spinal cord injury. Seventeen patients having pressure ulcers in the pelvic region were randomly assigned to either an HVPC group or a placebo HVPC group. Treatments were given for 1 hour a day for 20 consecutive days. The HVPC protocol consisted of an aluminum-foil electrode placed over the ulcer and set at negative polarity in reference to the dispersive electrode placed on the thigh. Stimulator frequency was set at 100 pps, and an intensity of 200 V was used. Measurements of ulcer surface area were conducted before treatment and after treatment days 5, 10, 15, and 20. To measure ulcer area (in square millimeters), slides taken at each measurement time were projected at actual size, traced, and digitized. Percentage of change compared with pretreatment ulcer size was calculated for each measurement time. Ulcers in the HVPC group demonstrated significantly greater percentage-of-change decreases from their pretreatment size than did ulcers in the placebo group at days 5, 15, and 20. The results suggest that HVPC, in conjunction with good nursing care, can significantly increase the healing rate of pelvic ulcers in patients with spinal cord injury.

Measurement of pressure ulcer volume using dental impression materials: suggestion from the field.

Understanding of the healing rates of deep pressure ulcers may be enhanced in future studies by relating changes in wound volume to changes in WSA. In this report, a type of dental impression material, vinyl polysiloxane, was used to produce a model of the internal topography of a pressure ulcer. This model was used to obtain volumetric measurements of the wound cavity. A permanent replica (cast) of the wound was also fabricated. Further clinical trials investigating the reliability of this method for measuring the volume of deep pressure ulcers are indicated.

Effect of viscoelastic insoles on pain.

The purpose of this study was to assess the effect of viscoelastic shoe inserts on pain in nursing students. Students (N = 100) were randomly assigned to control and viscoelastic groups. The viscoelastic group used viscoelastic insoles in their work shoes for five weeks. A pain questionnaire was used to measure location and intensity of post-work pain. The questionnaire was administered as a pre-test and after five weeks. Post-test comparisons between groups indicated significant differences which were not present at pre-test. The viscoelastic group reported a significant peripheral shift in pain location from back to lower extremity; the viscoelastic group also showed significant changes in duration of post-work pain and frequency of pain during the workday. The clinical efficacy of viscoelastic shoe inserts for modifying weight bearing-induced back pain is supported. Further clinical research into the therapeutic and prophylactic value of shock-attenuating shoe inserts for healthy as well as patient populations is advocated.

Compression-plate fixation in acute diaphyseal fractures of the radius and ulna.

At the Campbell Clinic and City of Memphis Hospital from 1960 to 1970, 244 patients (216 with closed and twenty-eight with open fractures) had 330 acute diaphyseal fractures of the radius and ulna which were treated with ASIF compression plates and followed for from four months to nine years. One hundred and twelve patients had fractures of both bones of the forearm; fifty, single fractures of the ulna; and eighty-two, single fractures of the radius. In all, 193 fractures of the radius and 137 fractures of the ulna were treated by compression plating. Sixty-three patients (25.9 per cent) with severely comminuted fractures also had iliac-bone grafts. The over-all rate of union for the radius was 97.9 per cent and for the ulna, 96.3 per cent. ASIF compression plates, therefore, provided a successful method for obtaining union and restoring optimum function after acute diaphyseal fractures of the forearm.