Presidential address. "Some of the king's horses...".
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Adult↗
Biomedical subjects
D G Murray
Publications and source records attributed to D G Murray.
Early failure of the femoral component in unicompartmental knee arthroplasty.
Unicompartmental knee arthroplasty has been proposed as treatment for unicompartmental arthritis. Overall, results have been satisfactory, with occasional failures of tibial component fixation. Short-term loosening of the femoral components in unicompartmental knee arthroplasty that required revision to total knee arthroplasty is reported. All patients presented with pain and instability of the knee, with loosening confirmed radiographically and at revision surgery. The Porous-Coated Anatomic femoral component (Howmedica, Rutherford, NJ) was biomechanically tested after being implanted in cadaver limbs. Cyclic loading in flexion and extension under physiologic loads resulted in implant failure. The mode of failure was rocking in the sagittal plane, which corresponds to the clinical findings. The femoral implant design consists of an angled bone-implant interface with straight arms, which causes shear at the bone-prosthesis interface did not loosen under identical biomechanical testing in paired knees. It was concluded that the Porous-Coated Anatomic femoral component has an unacceptably high early clinical loosening rate, confirmed by comparative biomechanical testing.
Aged↗
Blood salvage after total hip arthroplasty.
We performed a prospective, randomized study to determine the effect of postoperative collection and reinfusion of unwashed, filtered, salvaged blood on the transfusion requirements of 232 patients managed with a total hip replacement. Patients who were scheduled to have a primary or revision procedure were advised to predeposit two or four units of autologous blood, respectively, before the operation. In addition, intraoperative blood salvage was performed for all patients who had a revision procedure. The patients were randomly assigned to one of two groups: the first group was managed with postoperative blood salvage with use of the Autovac Postoperative Orthopaedic Autotransfusion Canister and the second, with closed suction drainage with use of the Hemovac system. In the first group, blood was collected from wound drains for four hours postoperatively; if at least 300 milliliters of blood was collected, the unwashed blood was reinfused through a microaggregate filter during a two-hour period. A maximum of 1000 milliliters of salvaged blood was reinfused; any blood that had not been reinfused within six hours after the beginning of collection was discarded. No complications or episodes of hypotension, confusion, cardiac or pulmonary compromise, febrile reaction, or coagulopathy were observed during or after the reinfusion of the unwashed, filtered, salvaged blood. No reinfusions were interrupted or discontinued. We found that postoperative reinfusion of unwashed, filtered, salvaged blood was associated with a decreased prevalence of homologous transfusion after a total hip replacement among patients for whom preoperatively donated autologous blood was not available.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Symposium: options in transfusion therapy.
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Adult↗
A gene associated with cell division and drug resistance in Giardia duodenalis.
A 3000 bp cDNA insert (G6/1) from Giardia duodenalis, cloned into Escherichia coli is located on chromosome 3 of Giardia stocks which have 3 chromosomes detectable by field-inversion gel electrophoresis in the range 650-800 kb and on chromosome 3 and/or 4 of stocks with 4 chromosomes in this size range. The loss of this sequence from chromosome 4 but not chromosome 3 was associated with the induction of drug resistance in a previously sensitive laboratory stock. G6/1 appears to represent a single copy gene in Giardia as determined by hybridization of the probe to cleaved genomic DNA. Furthermore, the sequences flanking at least 12 kb of G6/1 are the same when G6/1 appears on both chromosomes 3 and 4. The cDNA encodes a protein associated with the nuclei of trophozoites during some stages of growth of the parasite. In a non-dividing culture, the antigen is associated with the nuclei of about 30% of trophozoites and fewer in a dividing culture. Three Giardia stocks with obvious chromosome rearrangements, which grow poorly and fail to divide normally, apparently lack the DNA sequence G6/1.
Animals↗
Knee extensor mechanics after subtotal excision of the patella.
Two sets of six fresh frozen autopsy specimens were used to test the quadriceps force requirements for knee extension after sequential distal-to-proximal and proximal-to-distal excisions of the patella. The quadriceps force as a function of knee flexion angle was recorded for varying amounts of excision and compared with the results for total patellectomy. Excision of the proximal one half or less resulted in lower force requirements when compared with total patellectomy. The effects of removal of the proximal three-fourths length of patella were inconsistent and actually increased the force requirements in three knees. The effects of distal to proximal excisions indicate a biomechanical advantage to maintaining a fragment equal to at least three fourths the length of the proximal patella. Retaining a fragment of adequate size preserves at least some of the mechanical advantage provided by the intact patella.
Aged↗
Blood products: optimal use, conservation, and safety.
A review of our experience in total joint arthroplasty revealed that the cell saver was not cost-effective in the case of routine primary hip or knee replacement. Its use should be restricted to cases of revision hip and knee surgery in which infection has been ruled out. Preoperative aspiration remains the most reliable method for accomplishing this. However, if the aspiration is negative and the intra-articular fluid obtained at the time of surgery is suspicious for infection, either in appearance or on Gram stain or cell count, it is best to abandon use of the cell saver. Predonation should be routine for all hip replacement cases unless there are specific contraindications. In general, there is good acceptance of this program by patients, although a few have specifically indicated they would prefer to run the risk of homologous transfusion. Two units available for primary replacement are more than ample. In cases of revisions, a first revision justifies a minimum of 3 units. For complex revision cases involving patients with three or more previous procedures on the hip, or those requiring significant bone resection or large segment grafting, the maximum possible number of units should be obtained. Autologous blood reinfusion should be done for essentially the same indications as homologous transfusion even though risks are sharply reduced. The local source for autologous collection will then follow its own specific protocol for the disposition of remaining units. In every case, the surgical technique should be careful and directed toward limiting intraoperative blood loss.
Blood Transfusion, Autologous↗
Aircraft management, OR management, and the surgical safety window.
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Accident Prevention↗
Mechanical factors in electrode-induced osteogenesis.
Previous experiments have suggested that mechanical activity of electrode implants may contribute to the observed bone formation that has been attributed to the electrical currents. This was tested by implanting movable and stationary wires in the medullary canal of the rabbit femora or tibiae. The moving implants uniformly showed significant medullary bone formation at the wire, whereas the stationary ones did not. This bone persisted for as long as 8 weeks and was mostly resorbed by 12 weeks as the implants became fixed. The new trabecular bone closely resembled that typically seen at electrically active implants. Implant motion may have a more important role in electrically induced osteogenesis than previously thought.
Animals↗
In vivo construction of a metal-backed, high-molecular-weight polyethylene cup during McKee-Farrar revision total joint arthroplasty. A case report.
The need for revision total hip arthroplasty after metal-to-metal articulating prostheses is well known. An alternative to conventional acetabular revision in the clinical circumstance of isolated femoral component loosening is in vivo construction of a metal-backed, high-molecular-weight polyethylene (HMWPE) acetabular component. This surgical approach reduces the likelihood of intraoperative acetabular bone loss, should minimize subsequent loosening, and virtually eliminates the source of metallic wear debris. Follow-up evaluation after 3 years revealed maintenance of the acetabular component position and a satisfactory clinical result. In vivo construction of a metal-backed HMWPE acetabular component is an effective alternative in the management of this potentially difficult orthopedic problem.
Acetabulum↗
Experience with the variable axis knee prosthesis.
In an evaluation of 245 variable axis total knee arthroplasties, no significant deterioration of results were found five to nine years after implantation. The patellar problems originally reported diminished with the use of a patellar button, widening of the flange on the femoral component and the increased use of lateral retinacular release. The local complications were: severe patellar problems, 6.9%; ligamentous laxity, 2.9%; aseptic loosening, 1.2%; deep infections, 2.0%; supracondylar fractures, 1.2%; peroneal nerve palsy, 1.6%.
Aged↗
Complications of Variable Axis total knee arthroplasty.
Three hundred seventy-six patients were treated by a Variable Axis total knee arthroplasty between 1974 and 1980 and were reviewed for mechanical and orthopedic complications of their surgery. Sixty-five patients had significant complications. Twenty-eight (7.4%) patients developed significant problems with their patellae, 13 (3.4%) patients required reoperation for patellar realignment, and four (1.0%) patients had a patellar resurfacing for retropatellar pain. Two (0.5%) cases of aseptic loosening of the femoral component required revision surgery. There was no aseptic loosening of the tibial component. Other complications included a ligamentous instability (2.9%), postoperative joint stiffness (1.6%), peroneal nerve palsy (1.3%), supracondylar fractures (1.0%), and postoperative joint infection (1.8%).
Femoral Fractures↗
Total knee replacement with a variable axis knee prosthesis.
The Variable Axis Knee Prosthesis was designed to accommodate a wide range of problems in the knee and to minimize the complication of loosening. The results of the series, which now spans over seven years at this institution, have confirmed the effectiveness of the prosthesis in providing stability and firm fixation. Patellar alignment remains critical for optimum results. A wide variety of abnormalities, including failed prostheses, severe flexion contractures, arthrodesed knees, and severely osteoporotic bone, can be effectively managed utilizing this device. As with any other total knee prosthesis, the use of this prosthesis should be restricted to those knees with definite radiographic evidence of joint impairment in addition to significant symptoms. Relative contraindications include previous sepsis, neuropathic joint disease, and gross ligamentous incompetency. If these indications and limitations are adhered to, the results from knee replacement can be expected to equal or exceed those from total hip replacement over the long term.
Arthritis, Rheumatoid↗
Twisted trees and tempests.
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Education, Medical, Continuing↗
The relationship between tourniquet pressure and underlying soft-tissue pressure in the thigh.
UNLABELLED: Soft-tissue pressures in specimens of the lower extremities of cadavera, obtained following hip disarticulation, were measured directly beneath a pneumatic thigh tourniquet to establish the relationship between the tourniquet pressure and underlying soft-tissue pressure. It was found that the tissue pressure was consistently lower than the tourniquet pressure and that the percentage of tourniquet pressure reflected in the underlying tissue varied inversely with the circumference of the thigh. It was also found that the pressure decreased with increasing depth of the soft tissue. CLINICAL RELEVANCE: the use of a pneumatic tourniquet is potentially associated with injury to underlying muscles, vessels, and nerves if excessive pressure occurs beneath the tourniquet. In order to minimize the risk of soft-tissue injury, the lowest tourniquet pressure that maintains a bloodless field should be used. A nomogram based on data generated in this experiment is provided as a guide to determining appropriate tourniquet pressures.
Anthropometry↗
Mechanisms of arterial injuries associated with total hip replacement.
Five cases of arterial complications of total hip replacement, all of which can be explained on the basis of intraoperative injury, are reported, with diagrammatic analysis of the intraoperative mechanisms of injury involved. The injuries were manifested as hemorrhage, ischemia, or development of a pulsatile mass. Vascular structures affected include the external iliac, common femoral, medial femoral circumflex, and lateral femoral circumflex arteries. Arterial damage may result from retractor injury, thermal injury from methylmethacrylate, or direct penetration from polymer or gouging during acetabular preparation. An understanding of the mechanisms and location of arterial injury following hip replacement will aid the vascular surgeon in diagnosis, exposure, and repair of these injuries.
Aged↗
Chronic bladder herniation associated with pubic diastasis.
We present a case report of chronic bladder herniation following a vertical abdominal incision in a patient with a long-standing post-traumatic pubic diastasis. Fascial repair was successful after the defect was bridged with a cortical bone graft to supply anchorage for the repair. A successful fascial repair seemed to be contingent upon reestablishment of a competent anterior pelvic ring.
Aged↗
The variable-axis knee prosthesis. Two-year follow-up study.
This study reports the clinical results following knee replacement with the variable-axis knee prosthesis. All patients have been followed for a minimum of two years. The first consecutive fifty-two patients, comprising a total of fifty-five knee replacements, were personally reviewed by an independent evaluator. The results on a subjective basis consisted of 79 per cent good to excellent results, 15 per cent fair results, and 6 per cent failures. Failures were related to infection or continued pain. Fair results reflected some patellar discomfort or instability. There was no detectable clinical loosening of the components in any patient. To date, the design of the variable-axis prosthesis appears to offer promise in the control of the complication of prosthetic loosening.
Adult↗