Clinical validation of a structural porous tantalum biomaterial for adult reconstruction.
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Adult↗
Biomedical subjects
D G Lewallen
Publications and source records attributed to D G Lewallen.
The kinematic rotating hinge prosthesis for complex knee arthroplasty.
Fifty-eight patients (69 knees) treated with the Kinematic Rotating Hinged knee prosthesis for complex primary and salvage revision total knee arthroplasty were followed up for an average of 75.2 months (range, 24-199 months). The indications for use of the Kinematic Rotating Hinged knee prosthesis included severe bone loss combined with ligamentous instability (30 knees), nonunion of a periprosthetic fracture (10 knees), an acute periprosthetic fracture (nine knees), severe collateral ligamentous instability (five knees), reimplantation for infection (six knees), nonunion of a supracondylar femoral fracture (four knees), congenital dislocation of the knee (three knees), and treatment of a severely comminuted distal femur (two knees). At the time of surgery, the average patient age was 72 years (range, 46-92 years). Preoperatively, knee extension averaged 4.94 degrees (range, 0 degrees-40 degrees) and flexion averaged 81 degrees (range, 15 degrees-125 degrees). At final followup, knee extension averaged 1.25 degrees (range, -5 degrees-25 degrees) and flexion averaged 94.2 degrees (range, 5 degrees-125 degrees). The preoperative Knee Society Knee score averaged 40.3 points (range, 2-93 points) and improved to 77 points (range, 33-99 points) at final followup. Complications were numerous: 23 (32%) patients experienced at least one complication and 12 (17%) patients had two or more complications. Deep periprosthetic infection was the most common complication (14.5%), followed by patellar complications (13%), and prosthetic component breakage (10%). During the period of this study, there were 15,798 primary and 2673 revision total knee arthroplasties done at the authors' institution. The patients receiving a Kinematic Rotating Hinged knee prosthesis represent a highly complex and small subset (0.37%) of the overall population having knee arthroplasty. Although the use of the Kinematic Rotating Hinged knee prosthesis for these limited indications has been useful for the authors, the incidence of complications and the poor outcome of these complications is disconcerting. Hinged total knee arthroplasty should be reserved for the final salvage option of the treatment options available when doing complex primary and salvage revision knee arthroplasties.
Aged↗
Thirty-day mortality after total knee arthroplasty.
BACKGROUND: There have been sporadic reports on perioperative mortality associated with total knee arthroplasty. The purpose of this study was to determine risk factors for such mortality. METHODS: A computer-assisted review of the records of 22,540 consecutive patients who had undergone total knee arthroplasty between 1969 and 1997 was performed to identify all patients who had died within thirty days after the procedure. A detailed analysis of the medical, surgical, anesthetic, and pathological records of the patients was performed, and the mortality was determined according to age, gender, diagnosis, and fixation method. RESULTS: The rate of mortality within thirty days after the operation was 0.21% (forty-seven of 22,540). All deaths occurred in the group of 18,810 patients who had received a cemented implant, and no deaths occurred among the 3730 patients who had received an uncemented implant (p < 0.0001). The mortality rate was 0.24% (forty-three of 18,165) after primary arthroplasty and 0.09% (four of 4375) after revision arthroplasty (p < 0.0003). Three patients (0.01%) died during the operation. Forty-three of the forty-seven patients who died had a history of preexisting cardiovascular and/or pulmonary disease. Simultaneous bilateral total knee arthroplasty was associated with a significantly higher rate of perioperative mortality (p < 0.002). CONCLUSIONS: Factors that were associated with a significantly increased mortality after total knee arthroplasty included an age of more than seventy years, primary (as compared with revision) knee surgery, use of a cemented prosthesis, preexisting cardiopulmonary disease, and simultaneous bilateral arthroplasty.
Aged↗
Thirty-day mortality after elective total hip arthroplasty.
BACKGROUND: Previous reports on perioperative mortality associated with hip arthroplasty have not documented, to our knowledge, patient characteristics and surgical factors that increase the likelihood of death. The purpose of this study was to determine the prevalence of and associated risk factors for perioperative death after elective hip arthroplasty. METHODS: The records of 30,714 consecutive patients who had undergone elective hip arthroplasty at our institution from 1969 to 1997 were retrospectively reviewed to identify patients who had died within thirty days after the procedure. Mortality rates were determined according to age, gender, diagnosis, implant type, and fixation mode. RESULTS: Ninety deaths occurred within thirty days after elective total hip arthroplasty, for an overall mortality rate of 0.29% (ninety of 30,714). The thirty-day mortality rate was significantly higher for patients with preexisting cardiovascular disease (p < 0.0001), male patients (p < 0.0001), and patients who were seventy years of age or older (p < 0.0002). The mortality rate was slightly, but not significantly, higher for patients with an underlying diagnosis of rheumatoid arthritis (p < 0.36) and those receiving cemented implants (p < 0.57). There was no difference in the thirty-day mortality rate for revision as compared with primary hip arthroplasty (p < 0.92). CONCLUSIONS: Factors that are associated with an increased risk of mortality within thirty days after elective hip arthroplasty include an older age, male gender, and a history of cardiorespiratory disease. There has been a significant decline in the thirty-day mortality rate after elective hip arthroplasty in the last decade (p < 0.0002); during the 1990s, the overall rate at our institution was 0.15% (twenty-three of 14,989).
Aged↗
Vertebral osteomyelitis and prosthetic joint infection due to Staphylococcus simulans.
Staphylococcus simulans, a coagulase-negative staphylococcus, is a common animal pathogen that is rarely encountered in human infections. We describe a 70-year-old man who developed multifocal vertebral osteomyelitis and late prosthetic joint infection caused by this pathogen. The patient was a farmer who had daily contact with cows and drank unpasteurized milk, although the portal of the pathogen's entry remains speculative. Culture of the vertebral disk biopsy specimen and cultures during resection arthroplasty yielded S. simulans. A review of the literature suggests that S. simulans may be more virulent than other species of coagulase-negative staphylococci. Accurate identification of S. simulans isolates would facilitate studies to further define its pathogenic role in human infections.
Agriculture↗
Low-intensity ultrasound stimulates proteoglycan synthesis in rat chondrocytes by increasing aggrecan gene expression.
We evaluated the effect of low intensity-pulsed ultrasound stimulation on rat chondrocytes in vitro using two different 1.0-MHz ultrasound signals with spatial and temporal average intensities of 50 or 120 mW/cm2. The pulses had a duration of 200 microseconds and were repeated every millisecond, with corresponding average peak-pressure amplitudes of 230 or 360 kPa, respectively. Cells were stimulated one, three, or five times for 10 minutes each day starting the third day after plating. One group of cells was exposed to sham ultrasound as a control. The cultures were evaluated for cell proliferation (by [3H]thymidine incorporation and DNA measurement), steady-state mRNA levels of alpha1(I) and alpha1(II) procollagens and aggrecan (by Northern blotting), and proteoglycan synthesis (by [35S]sulfate incorporation). The results revealed that ultrasound causes increases in the level of aggrecan mRNA (p < 0.05) and in proteoglycan synthesis (p < 0.03) after three and five treatments. Expression of mRNA for alpha1(II) procollagen increased over time, but ultrasound had no stimulatory effect. Expression of mRNA for alpha1(I) procollagen was initially low and remained unchanged with time. Although cell proliferation increased with time in both groups, there was no statistically significant difference between the cultures treated with ultrasound and the controls (p = 0.1). The in vitro results support our previous in vivo findings that low-intensity ultrasound stimulates aggrecan mRNA expression and proteoglycan synthesis by chondrocytes, which may explain the role of ultrasound in advancing endochondral ossification, increasing the mechanical strength of fractures, and facilitating fracture repair.
Aggrecans↗
The Frank Stinchfield Award. Sudden death during primary hip arthroplasty.
The records of 23 patients who died intraoperatively during hip arthroplasty at the authors' institution were reviewed. Of the 38,488 hip arthroplasties in 29,431 patients performed between 1969 and 1997, there were 23 deaths during surgery. There were 15 women and eight men with a mean age of 80.9 years. Preoperative diagnoses were acute hip fracture (13 patients), pathologic fracture (four patients), femoral neck nonunion (one patient), osteoarthritis (four patients), and rheumatoid arthritis (one patient). Eleven patients undergoing cemented total hip arthroplasty died and 12 patients undergoing cemented hemiarthroplasty died. All deaths occurred because of irreversible cardiorespiratory disturbances that were initiated during cementing. There were no deaths among 12,551 patients receiving 15,411 uncemented hip arthroplasties during the 28-year period under review. Autopsy was performed in 13 patients. Bone marrow microemboli were seen in the lungs of 11 of 13 patients in whom an autopsy was performed and methylmethacrylate particles were seen in the lungs of three of 13 patients. These data suggest that elderly patients with preexisting cardiovascular conditions undergoing cemented arthroplasty, especially for fracture diagnosis, are at increased risk for intraoperative death compared with patients undergoing elective hip arthroplasty. In the latter years of the current study, modifications of the operative techniques designed to minimize intramedullary hypertension were associated with a reduction greater than three-fold in overall intraoperative mortality rate. These changes in surgical technique should be considered when cement fixation is used in patients thought to be at risk for having cardiopulmonary disturbances develop from venous embolization of marrow contents.
Age Distribution↗
Hip arthroplasty in patients with Paget's disease.
In individuals with Paget's disease, the pelvis and upper femur are the areas of the skeleton most frequently involved. Associated deformities and alterations in bone quality can complicate total hip arthroplasty when required for degenerative joint changes, and can compromise outcome. A review of reported series shows that patients with Paget's disease may present unique problems during the preoperative assessment, intraoperative treatment, and postoperative followup. Preoperative determination of disease activity and assessment of the cause of hip symptoms is important. Intraoperatively, deformity such as coxa vara, femoral bowing, acetabular protrusio, and bony enlargement may cause alterations in implant choice or fixation method used and the patient may even require corrective osteotomy. Excessive bleeding and bone quality changes may complicate these efforts additionally. Postoperative problems include heterotopic bone formation, and in those patients in whom the underlying disease is highly active or poorly controlled, rapid postoperative bone resorption is possible. Results of cemented arthroplasty in patients with Paget's disease have been reported as comparable with but slightly worse than the results reported for unselected patients who underwent hip arthroplasty. The long-term results of uncemented implants in patients with Paget's disease remains to be established.
Arthroplasty, Replacement, Hip↗
Nonunion after periprosthetic femoral fracture associated with total hip arthroplasty.
BACKGROUND: Nonunion after a periprosthetic femoral fracture associated with total hip arthroplasty occurs rarely. There is little information, to our knowledge, regarding the prevalence of this complication, its treatment, and the functional outcomes of treatment. The purpose of this study was to identify the patterns and frequency of nonunions of femoral fractures around total hip prostheses and to evaluate the results and problems associated with treatment of this complication in a consecutive series of patients. METHODS: The study included twenty-three nonunions of periprosthetic femoral fractures in twenty-three patients with an average age of fifty-five years (range, twenty-two to eighty-five years) at the time of the initiation of treatment of the nonunion. Thirteen of the fractures occurred during or after a primary total hip arthroplasty, and ten occurred during or after a revision total hip arthroplasty. According to the classification system of Duncan and Masri, there were six B1 fractures (associated with a well fixed prosthesis), seven B2 fractures (associated with a loose stem), and ten B3 fractures (associated with very poor proximal bone). Ten patients were managed with revision to a long-stem prosthesis. Six patients had revision to a proximal femoral replacement prosthesis. A two-stage technique consisting of removal of the prosthesis and open reduction and internal fixation of the nonunion followed by reimplantation of the prosthesis was used in two patients. Two patients were managed initially with bone-grafting alone, and two patients were managed nonoperatively. One patient who had an infection at the site of the nonunion was managed definitively with resection arthroplasty. RESULTS: The duration of clinical follow-up averaged 8.3 years (range, three months to twenty-three years), and that of radiographic surveillance averaged 7.0 years (range, eight months to seventeen years). Of the thirteen patients in whom an attempt to achieve union was made and for whom radiographs were available, nine eventually had bone-healing. Five of the twenty-three femora became infected and were treated with resection arthroplasty. Of the seventeen patients who had not had a resection arthroplasty for infection and for whom radiographs were available at the time of the most recent follow-up, eleven had a stable and well fixed implant and six had a loose implant as seen radiographically or had had a revision because of aseptic loosening. Seventeen patients had no or mild pain at the time of the most recent follow-up, but ten required two-handed support to walk. The overall complication rate was 52 percent (twelve of twenty-three patients). CONCLUSIONS: Nonunion of a femoral fracture associated with a total hip prosthesis is an infrequent problem. Treatment is difficult, with a high rate of complications and relatively poor functional outcomes. The data from this series must be interpreted with caution, as patients were managed over a period of three decades and many did not have the advantage of modern techniques of revision hip arthroplasty. Prevention of nonunion by optimum treatment of the initial fracture is most important. Treatment of a femoral nonunion about a total hip implant should be implemented on the basis of the status of the fixation of the prosthesis and the quality of the surrounding bone.
Adult↗
Pelvic discontinuity in revision total hip arthroplasty.
BACKGROUND: Pelvic discontinuity is a distinct form of bone loss, occurring in association with total hip arthroplasty, in which the superior aspect of the pelvis is separated from the inferior aspect because of bone loss or a fracture through the acetabulum. The purpose of this study was to describe the population of patients who are at risk for this condition, to identify the characteristic radiographic features associated with it, and to report the results of revision total hip arthroplasty for the treatment of pelvic discontinuity. METHODS: The cases of all twenty-seven patients (thirty-one hips) who were identified as having a pelvic discontinuity at the time of a reoperation for a failed hip arthroplasty at one institution were reviewed retrospectively, and demographic information was collected. The preoperative radiographs and the operative notes were reviewed, and the postoperative results and complications were recorded. RESULTS: Pelvic discontinuity was identified in association with thirty-one (0.9 percent) of 3505 acetabular revisions. The mean age of the patients was sixty-one years (range, thirty-eight to eighty years). Twenty-eight hips were in women, and three were in men. Women (p < 0.001) and patients who had rheumatoid arthritis (p = 0.003) had a significantly increased risk of pelvic discontinuity. The radiographic findings included a visible fracture line through the anterior and posterior columns, medial translation of the inferior aspect of the hemipelvis relative to the superior aspect (seen as a break in Kohler's line), and rotation of the inferior aspect of the hemipelvis relative to the superior aspect (seen as asymmetry of the obturator rings) on a true anteroposterior radiograph. Two patients died within two years after the revision, and two had a resection arthroplasty for the treatment of the pelvic discontinuity; thus, twenty-seven hips were reconstructed and were eligible for follow-up at least two years after the operation. A number of different methods were used for reconstruction, but the results were best in patients who did not have severe segmental acetabular bone loss (type IVa [a satisfactory result in three of three hips]) and poorer in those who had severe segmental or combined segmental and cavitary bone loss (type IVb [a satisfactory result in ten of nineteen hips]) and in those who previously had been treated with irradiation to the pelvis (type IVc [a satisfactory result in three of five hips]). Nine of the twenty-seven hips needed another operation: four, because of aseptic loosening of the acetabular component; four, because of recurrent dislocation; and one, because of deep infection. Excluding three hips that were revised early because of infection or dislocation, a mechanically stable construct (that is, a stable socket and a possibly or definitely healed discontinuity) was obtained in seventeen of twenty-four hips. CONCLUSIONS: Pelvic discontinuity is uncommon, and treatment is associated with a high rate of complications. For hips with type-IVa bone loss and selected hips with type-IVb defects, in which a socket inserted without cement can be satisfactorily supported by native bone, we prefer to use a posterior column plate to stabilize the pelvis and a porous-coated socket inserted without cement. For most hips with type-IVb and type-IVc bone loss, we prefer to use particulate bone graft or a single structural bone graft protected with an antiprotrusion cage.
Acetabulum↗
The role of methylmethacrylate monomer in the formation and haemodynamic outcome of pulmonary fat emboli.
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Animals↗
Flexion instability after primary posterior cruciate retaining total knee arthroplasty.
Between 1990 and 1995, 25 painful primary posterior cruciate ligament retaining total knee arthroplasties were revised for flexion instability. These patients shared typical clinical presentations that included a sense of instability without frank giving way, recurrent knee joint effusion, soft tissue tenderness involving the pes anserine tendons and the retinacular tissue, posterior instability of 2+ or 3+ with a posterior drawer or a posterior sag sign at 90 degrees flexion, and above average motion of their total knee arthroplasty. The primary total knee arthroplasty was performed for osteoarthritis in 23 patients and rheumatoid arthritis in two patients. There were 13 male and 12 female patients and their mean age was 65 years (range, 35-77 years). Before the revision operation, Knee Society knee scores averaged 45 points (range, 17-68 points) and function scores averaged 42 points (range, 0-60 points). Twenty-two of the knee replacements were revised to posterior stabilized implants and three underwent tibial polyethylene liner exchange only. Nineteen of the 22 knee replacements revised to a posterior stabilized implant were improved markedly after the revision surgery. Only one of three knee replacements that underwent tibial polyethylene exchange was improved. After the revision for flexion instability, Knee Society knee scores averaged 90 points (range, 82-99 points) and function scores averaged 75 points (range, 45-100 points) for the 20 knees with a successful outcome. This study suggests that flexion instability can be a cause of persistent pain and functional impairment after posterior cruciate ligament retaining total knee arthroplasty. A revision operation that focuses on balancing the flexion and extension spaces, in conjunction with a posterior stabilized knee implant, seems to be a reliable treatment for symptomatic flexion instability after posterior cruciate retaining total knee arthroplasty.
Adult↗
Periprosthetic fracture of the femur after total hip arthroplasty: treatment and results to date.
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Arthroplasty, Replacement, Hip↗
Neurovascular injury associated with hip arthroplasty.
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Arthroplasty, Replacement, Hip↗
Exposure to low-intensity ultrasound increases aggrecan gene expression in a rat femur fracture model.
The effects of ultrasound stimulation on various parameters of bone repair after diaphyseal injury were assessed in a standard rat femur fracture model. Bilateral closed femoral fractures were made in 79 skeletally mature male Long-Evans rats. An ultrasound signal consisting of a 200 microsecond burst sine wave of 0.5 MHz repeating at 1 kHz, with an intensity of 50 or 100 mW/cm2 spatial and temporal average, was applied to one fracture in each animal. The contralateral fracture was not exposed to ultrasound and served as a control. Mechanical testing of the healing fracture was performed 3 weeks after injury. In fractures treated with a 50 mW/cm2 ultrasound signal, the average maximum torque (223.5 +/- 50.5 Nmm compared with 172.6 +/- 54.9 Nmm, p = 0.022, paired t test) and average torsional stiffness (13.0 +/- 3.4 Nmm/degree compared with 9.5 +/- 2.9 Nmm/degree, p = 0.017) were significantly greater in treated than in control fractures. In animals treated with a 100 mW/cm2 ultrasound signal, the average maximum torque and torsional stiffness were greater in treated than in control fractures, but this trend did not reach statistical significance. Biochemical analysis of callus in ultrasound-treated and control fractures failed to demonstrate significant differences in cell number, collagen content, or calcium content. Evaluation of gene expression in fractures treated with 50 mW/cm2 ultrasound demonstrated a shift in the expression of genes associated with cartilage formation; aggrecan gene expression was significantly higher on day 7 after fracture and significantly lower on day 21 (p = 0.033 and 0.035, respectively). alpha 1(II) procollagen gene expression was similarly modified, but this trend did not reach statistical significance. Expression of genes coding for bone-related proteins, including alpha 1(I) procollagen, bone gamma-carboxyglutamic acid protein, alkaline phosphatase, and transforming growth factor-beta 1, did not differ between ultrasound-treated and control fractures. These data suggest that ultrasound stimulation increased the mechanical properties of the healing fracture callus by stimulating earlier synthesis of extracellular matrix proteins in cartilage, possibly altering chondrocyte maturation and endochondral bone formation.
Aggrecans↗
Femoral component revision using an uncemented, proximally coated, long-stem prosthesis.
Sixty-nine femoral component revisions with uncemented, metaphyseal-filling, proximally coated, chrome-cobalt, long-stem, curved prostheses were retrospectively reviewed 2 to 5 years after operation. The mean age of the patients was 62 years. The mean clinical follow-up period was 3 years, and the mean radiographic follow-up period was 2.8 years. Sixty-two hips underwent revision secondary to aseptic loosening after previous cemented total hip arthroplasty. Average preoperative Harris hip score was 51 points, which improved to 82 points. Complications included an intraoperative fracture in 45.9%. Repeat revision or component removal had been necessary in 6 patients (8.7%). An additional 14 patients (20%) had pain and radiographic evidence of subsidence. Overall 5-year survivorship free of moderate pain or revision was 82% for the entire group, but was 58% for the fracture subgroup at 4 years.
Adult↗
Total hip arthroplasty with femoral osteotomy for proximal femoral deformity.
Thirty-one total hip arthroplasties, 20 primary and 11 revision, combined with femoral osteotomy in 28 patients for a major proximal femoral deformity were reviewed an average of 4.6 years after surgery. The type of femoral osteotomy used was a uniplanar wedge in 19 cases, biplanar in 4, and step cut in 8. The Harris hip rating score improved from an average of 51 to 77 points in primary cases and from an average of 35 to 73 points in revision case. The average time until union of the osteotomy was 35 weeks. Complications included intraoperative femoral fracture in 7 cases, osteotomy nonunion in 4, instability in 4, aseptic femoral loosening in 4, osteolysis in 1, and deep infection in 1. Ten reoperations (32%) were performed in 8 patients. Total hip arthroplasty with concurrent femoral osteotomy is a technically demanding procedure. Stable initial fixation of the osteotomy is recommended to avoid osteotomy nonunion and failure.
Adult↗
Open fractures of the patella.
We retrospectively reviewed 57 open patella fractures treated at our institution between 1976 and 1989. Forty-four patients with 47 fractures (cases) were available for follow-up a mean of 9.4 years after injury (range 2.2-15.7). High-energy vehicular trauma was the cause of injury in > 90% of cases. Treatment included osteosynthesis in 50% of cases and patellectomy (partial or total) in the remainder. At follow-up evaluation, results were excellent in 17% of cases, good in 60%, fair in 17%, and poor in 6%. Nonunion occurred in two cases in which nonrigid internal fixation was used. The incidence of deep infection was 10.7%, and the infection rate correlated with the magnitude of soft-tissue injury. Two of the seven fractures (29%) treated with cerclage wiring became infected. None of the open type I and II fractures treated with immediate internal fixation or primary wound closure (or both) became infected. Therefore, we recommend immediate rigid internal fixation (other than cerclage wiring) of types I and II open patella fractures. Partial patellectomy of highly comminuted fractures provided results similar to those of internal fixation of less comminuted fractures. Thus, when comminution precludes fixation, partial patellectomy can be performed without hesitation. The timing of wound closure should be individualized.
Adolescent↗