Biomedical subjects

R A Balderston

Publications and source records attributed to R A Balderston.

At least 55 records · Page 3Linked to original sources

PubMed1992

Pulmonary embolism. Incidence in primary cemented and uncemented total hip arthroplasty using low-dose sodium warfarin prophylaxis.

During a 5 1/2-year period from January 1984 to July 1989, 736 patients between the ages of 50 and 75 with a diagnosis of osteoarthritis had either cemented or uncemented primary total hip arthroplasty. Patients were treated with low-dose sodium warfarin for prophylaxis against pulmonary embolism and had preoperative and postoperative serial lung scanning. The overall incidence of pulmonary embolism was not statistically different between the cemented and uncemented groups (3.87% and 6.19%, respectively; P > .05). Eighty-one percent of the pulmonary emboli were asymptomatic. The incidence of pulmonary embolism was higher in men than in women (7.3% and 2.93%, respectively; P < .05) but did not differ within each individual sex for the cemented and uncemented groups. Of greater significance, when the two initial groups were matched to control for sex and weight differences (564 patients), the incidence of pulmonary embolism narrowed to 4.3% and 5.3% in the cemented and uncemented groups, respectively (P > .55). These data indicate that the use of uncemented total hip arthroplasty does not offer any additional protective value against pulmonary embolism when using low-dose sodium warfarin prophylaxis.

Aged↗

PubMed1992

Noncontiguous injuries of the spine.

A total of 372 consecutive spinal injury patients were evaluated at the Regional Spinal Cord Injury Center of Delaware Valley. Of these, 39 patients (10.5%) were found to have noncontiguous spinal column injuries. Fewer than half of the patients in our series could be classified into previous classification systems (Calenoff, Gupta) of noncontiguous spinal fractures. Fifteen fractures in 12 patients were missed on presentation on admission and 25% of these patients had a progressive neurologic deficit as a result of improper initial immobilization. The location of missed fractures were found to be primarily at the extremes or junctures of the spine (i.e., cervicothoracic, thoracolumbar). Complete spinal roentgenographic evaluation is recommended in the workup of suspected spinal column injury patients, and additional imaging modalities (i.e., tomograms, computed tomography scans, and magnetic resonance imaging) may be necessary in those areas of the spine difficult to visualize.

Adolescent↗

PubMed1992

Pulmonary embolism in total hip and knee arthroplasty. Risk factors in patients on warfarin prophylaxis and analysis of the prothrombin time as an indicator of warfarin's prophylactic effect.

This study was designed to identify those total arthroplasty patients at high risk for embolism even while on a proven warfarin prophylactic regimen and to identify the measure of anticoagulation that would be most efficacious in the prevention of pulmonary embolism (PE). A series of 2348 total arthroplasty patients had a preoperative perfusion scan and a postoperative ventilation/perfusion scan. All patients were placed on a low-dose warfarin protocol. Eighty-one patients were identified as having a PE by pulmonary arteriography (incidence of 3.4%). Of these, 89% were asymptomatic and no case was fatal. A control group of 159 patients without PE was used for comparison. Patients older than 65 years of age with a history of genitourinary infection were identified as being at higher risk of PE while on a proven warfarin prophylactic program. These patients may need additional prophylactic measures to reduce the risk of PE. In contrast, patients with a history of phlebitis, PE, obesity, or varicosities were not at excess risk for PE while on warfarin prophylaxis; therefore, no additional prophylactic measures are required. All prothrombin time profiles were within the prophylactic range. Therefore, the actual prothrombin time may not be the critical determinant of the level of anticoagulation or prophylaxis achieved.

Analysis of Variance↗

PubMed1992

Primary total knee arthroplasty for displaced, acute intraarticular knee fractures. A report of four cases.

Primary total knee arthroplasty was performed in four patients with acute intraarticular fractures. All four were at high risk of failure for standard operative and nonoperative treatment because of severe osteopenia, preexisting intraarticular pathology, or a limited life expectancy. All benefited by early pain relief, functional range of motion, and early ambulation, with no early perioperative morbidity.

Acute Disease↗

PubMed1992

Posterior dislocation of total knee arthroplasty.

Posterior dislocation of the prosthesis after total knee arthroplasty is an infrequent but serious complication. Seven patients with this complication were treated from January 1985 until October 1989. Five of the seven dislocations occurred in primary total knee arthroplasties and two occurred after revision arthroplasty. Limb alignment before arthroplasty, when it could be determined, was valgus in all patients, averaging 25 degrees. In each case there was an identifiable problem with the knee extensor mechanism: five had patellar dislocations, one a patellar tendon rupture, and one a patellar fracture. In three of the posterior dislocations, there was also an imbalance of the flexion and extension gaps with excessive laxity of the ligaments in flexion. Treatment was individualized. In two patients, the knee was reduced closed and the patella subsequently tracked so that no reoperation was necessary. One ruptured patellar tendon could not be repaired in a 94-year-old patient with cardiac disease. A cylinder cast was applied with poor results. Operative intervention was required in four patients, one of whom required only a patellar realignment procedure. The three other patients required component revision procedures, however, in addition to patellar realignment procedures. In these three patients, laxity of the knee in flexion was so severe that posterior instability could not be corrected merely by patellar relocation. At a follow-up examination (average, 21 months postoperatively), all six patients who were treated as recommended had good results with no further dislocations, with the exception of the one patient with a patellar tendon rupture.

Aged↗

PubMed1991

Evaluation of the painful prosthetic joint. Relative value of bone scan, sedimentation rate, and joint aspiration.

Seventy-two joint arthroplasties undergoing total hip or total knee surgery were studied prospectively with plain radiographs, three-phase bone imaging (3PBI), erythrocyte sedimentation rate (ESR), aspiration of the joint for culture, and multiple intraoperative cultures at the time of revision. Intraoperative cultures and the operative appearance were used to form a diagnosis of definite infection (unequivocal microbiology and gross sepsis), possible infection (positive microbiology or gross sepsis), or no infection (neither positive microbiology nor gross sepsis). For the preoperative diagnosis of infection, as opposed to aseptic loosening, 3PBI alone had a sensitivity of 33% and a specificity of 86%. In conjunction with plain radiographs, minimal improvement in accuracy was seen. A preoperative ESR greater than 30 had low sensitivity (60%) and a specificity of (65%). However, the ESR was statistically significantly higher in the joints with definite infection as compared to those joints without infection. The preoperative joint aspiration had a sensitivity of 67% and a specificity of 96% and, therefore, appears to be the most useful single test in the workup of a painful total joint arthroplasty.

Aged↗

PubMed1991

Intervertebral disc injury complicating cervical spine trauma.

The incidence of acute herniated nucleus pulposus was determined in 55 patients with cervical spine trauma. A standardized protocol and a 1.5-T magnetic resonance image scanner was used to document a 42% incidence of acute herniated nucleus pulposus in patients studied within 72 hours of injury. The incidence of herniated nucleus pulposus was correlated with the patients' presenting neurologic status and mechanism of injury. The incidence of herniated nucleus pulposus was highest in patients with bilateral facet dislocations (80%) and anterior cord syndromes (100%). There was no statistically significant correlation between the incidence of herniated nucleus pulposus and patients' age or sex.

Adult↗

PubMed1991

Gastrointestinal complications in spinal cord injury.

Fifty-nine patients were identified with 70 gastrointestinal tract complications from a review of 950 spinal cord injury patients admitted during a 10-year period (prevalence 6.2%). When compared to a random spinal-cord-injured noncomplication control group (N = 31 patients), there was no difference in the percentage of low-dose steroids (dexamethasone 40 mg/day) given or in the percentage of patients receiving ulcer prophylaxis. All but two patients in the complication group received ulcer prophylaxis. Although an increase in the percentage of cervical and complete lesions was seen in the bleeding complications group, this increase was not statistically significant. The low complication rate (6.2%) seen in this study probably reflects the global use of ulcer prophylaxis and heightened awareness at a regional spinal cord injury center.

Female↗

PubMed1991

Total hip arthroplasty for osteonecrosis.

The success of Charnley cemented total hip arthroplasty for osteonecrosis of the femoral head was assessed using survival analysis. Eighty-seven total hip arthroplasties were followed up for an average of 5.7 years (range, 1.4-13.0 years). There were 59 women and 28 men. The average age was 60 years (range, 30-84 years). Using Charnley hip scores, all patients showed significant progress. The survival analysis showed that using femoral loosening, revision, and pain scores less than 5 as end points, survival was 0.61, 0.94, and 0.81, respectively. With revision as an end point, there were no differences between patients in groups less than 50 and greater than or equal to 50 years of age, weighing less than 185 and greater than =185 lb, and men versus women. There was an 11.5% overall revision rate. Charnley cemented total hip arthroplasty is a viable alternative for patients with painful osteonecrosis.

Adult↗

PubMed1991

Femoral neuropathy following total hip arthroplasty. Anatomic study, case reports, and literature review.

Femoral neuropathy is an uncommon yet debilitating complication of total hip arthroplasty (THA). Over a 1-year period, in 440 consecutive THAs performed at Pennsylvania Hospital, 10 (2.3%) femoral neuropathies occurred. Among primary arthroplasties, all neuropathies were associated with the Hardinge anterolateral approach. A retrospective case review as well as a detailed anatomic cadaveric study highlighted the characteristics of the femoral nerve that make it susceptible to injury. In addition, a review of the existing literature on this subject was performed. Placement and management of acetabular retractors were the factors most commonly associated with injury of the femoral nerve. All affected patients had significant initial disability. However, full femoral nerve. All affected patients had significant initial disability. However, full functional recovery occurred within 1 postoperative year. Clear understanding and awareness of the anatomy of the femoral triangle as well as accurate placement of anterior acetabular retractors can minimize the incidence of this complication.

Female↗

PubMed1991

Differentiation between spinal tumors and infections with magnetic resonance imaging.

Distinction between spinal tumors and infections is a frequent clinical dilemma. To assess the accuracy of magnetic resonance imaging in distinguishing between spinal tumors and spinal infections, 30 patients with proven spinal tumors or infections were studied. Magnetic resonance imaging correctly diagnosed spinal tumors and infections in 29 of 30 cases (97%): 21 of 22 tumors were correctly diagnosed, and 8 of 8 infections were correctly diagnosed. The following points were learned: 1) The most consistent finding of vertebral osteomyelitis was the involvement of the disc space and adjacent vertebral body with decreased signal intensity on the T1-weighted images and increased signal intensity on the T2-weighted images. On the contrary, the disc spaces in tumor cases were uninvolved and demonstrated normal intensities on both T1- and T2-weighted images. 2) Loss of definition of the vertebral endplate was more common with infection than with tumor. 3) Contiguous vertebral involvement was seen more frequently in infections than in tumors. 4) Soft tissue changes were quite helpful: fat planes were obscured diffusely due to edema in infection, whereas fat planes were frequently intact, or obscured only focally, in tumors. 5) Cord compression was accurately diagnosed by magnetic resonance imaging in both tumors and infections. Magnetic resonance imaging was found to be superior to other imaging modalities in its ability to detect tumors or infections early and in providing information on the bone, disc, soft tissue, and neural structures.

Adult↗

PubMed1991

The treatment of lumbar disc herniation: simple fragment excision versus disc space curettage.

The purpose of this study was to determine whether there was any difference in the clinical outcome between groups of patients treated with lumbar discectomy and vertebral endplate curettage as compared with disc fragment excision without endplate curettage. Eighty-three patients requiring lumbar disc excision for herniated nucleus pulposus were evaluated retrospectively at minimum 2-year follow-up. Forty-three patients had undergone fragment excision and disc space curettage at one center, whereas 40 patients underwent fragment excision without curettage at two other centers. There was no increased rate of reherniation or reoperation in the excision-only group. Vertebral endplate curettage carries a risk of annular penetration and damage to the great vessels. This study shows that this potentially dangerous step of the operation is unwarranted. In addition, patients who underwent endplate curettage had a higher incidence of low-back pain on follow-up.

Adult↗

PubMed1990

Survivorship analysis of 1,041 Charnley total hip arthroplasties.

Survivorship analysis of 1,041 cemented Charnley total hip arthroplasties performed as a primary procedure revealed a probability of component survival at 10 years of 92%; the probability of acetabular cup survival was 99% and of femoral component survival was 96%. Three-zone acetabular demarcation was present in 16% of cases, as was migration of the cup greater than 5 mm. However, the acetabular revision rate was 1.65%, confirming the long-term clinical durability of the 22-mm internal diameter cup. Radiographic evidence of definite femoral component loosening was present in 9.6% and high-grade femoral bone-cement demarcation was present in 3.5%. The isolated femoral revision rate was 1.8%. Based on detailed survivorship analysis, a high-risk group of patients was identified for component failure and for femoral component loosening (radiographic). These patients were male, young (less than 50 years), heavy (greater than 170 pounds), and active (not Charnley class C). Given these findings, it is difficult to justify the widespread use of noncemented total hip systems, except in identifiable high-risk patients.

Age Factors↗

PubMed1990

Radiographic demarcation of the acetabular bone-cement interface. The effect of femoral head size.

Between 1983 and 1988, 182 total hip arthroplasties were inserted using modern cement techniques including metal-backed acetabular components. Femoral head size was 32 mm in 84, 22 mm in 98. Radiographic analysis revealed three-zone demarcation of acetabular bone-cement interface in 56% of the 32 mm group as compared to 5% of the 22 mm group at 19 and 24 months mean follow-up period, respectively. When a subgroup of women under 60 years of age was created to control variables, the high-grade demarcation rates were 67% and 18%, respectively. Although Charnley hip scores remain similar between the two groups, these results emphasize the adverse effects of large femoral head prostheses on cement-bone interface and underline the need for alternative methods of fixation.

Aged↗

PubMed1990

Immediate closed reduction of cervical spine dislocations using traction.

Cervical facet dislocations may be reduced rapidly and effectively using axial traction with weights applied at over the traditional 45-pound limit. Fifty-three sequential patients with cervical facet dislocations were reviewed. Thirty-nine patients required more than 50 pounds of traction to achieve rapid reduction. Sixty-eight percent of the entire series showed significant improvement in neurologic function. There were no cases of significant loss of function. A cadaver study confirmed that the cranial tongs could support over 100 pounds of traction. Careful application of up to 100 pounds seems to be associated with a low risk of neurologic compromise or tong failure, but results in effective reduction of dislocations.

Aged↗

PubMed1990

Technique for occipito-cervical fusion in osteopenic patients.

A technique for occipito-cervical fusion in patients with upper cervical spine abnormalities and osteopenia is described and illustrated. This technique combines the use of autogenous bone graft and a polymethylmethacrylate (PMMA)-wire construct.

Aged↗

PubMed1990

Herniated lumbar disc in patients over the age of fifty.

Fifty patients ranging in age between 50-78 years (mean, 56) underwent surgery for a herniated lumbar disc between January 1986 and July 1988. All had objective clinical and radiographic evidence of a herniated disc. All had had failure during an appropriate period of conservative treatment. Far lateral herniation occurred in 8%, and 28% had disc herniations at L2 or L3. Surgical results were 64% excellent, 28% good, 6% fair, and 2% poor. Complications including urinary tract infection, wound infection, myocardial infarction, and pulmonary embolism were observed in 8% of patients. Lumbar disc herniation in the elderly is common. After thorough evaluation to exclude neoplasm or infection, decompression of neural structures can lead to 90% good to excellent results. Spinal stenosis must be carefully considered both preoperatively and intraoperatively. Also, a higher incidence of more cephalad lumbar herniations and far lateral herniations was observed in older patients.

Age Factors↗

PubMed1989

The prevention of pulmonary embolism in total hip arthroplasty. Evaluation of low-dose warfarin therapy.

The efficacy of low-dose warfarin therapy for prophylaxis of venous thromboembolic disease was studied prospectively in a group of 1,392 patients undergoing cemented total hip arthroplasty between 1978 and 1985. The incidence of both symptomatic and asymptomatic pulmonary emboli was determined after surgery in all patients using ventilation-perfusion lung scanning as the diagnostic endpoint. The total incidence of postoperative pulmonary embolus was 3.2%, with two-thirds asymptomatic and one-third symptomatic pulmonary emboli. There were no fatalities due to pulmonary embolism in the entire patient population. Bleeding complications requiring surgical intervention developed in 2.4% of patients. The authors conclude that low-dose warfarin therapy is a safe and easily administered form of inpatient treatment for prophylaxis of venous thromboembolic disease in all total hip arthroplasty patients and has demonstrated complete protection against fatal pulmonary embolism in this population.

Aged↗